Efficacy and Safety of Umbilical Cord-Derived Mesenchymal Stromal Cell Therapy in Preclinical Models of Sepsis: A Systematic Review and Meta-analysis

BACKGROUND

In preclinical studies, mesenchymal stromal cells (MSCs), including umbilical cord-derived MSCs (UC-MSCs), demonstrate the ability to modulate numerous pathophysiological processes related to sepsis; however, a systematic synthesis of the literature is needed to assess the efficacy of UC-MSCs for treating sepsis.

OBJECTIVE

To examine the effects of UC-MSCs on overall mortality (primary outcome) as well as on organ dysfunction, coagulopathy, endothelial permeability, pathogen clearance, and systemic inflammation (secondary outcomes) at prespecified time intervals in preclinical models of sepsis.

METHODS

A systematic search was conducted on Embase, Ovid MEDLINE, and Web of Science up to June 20, 2023. Preclinical controlled studies using in vivo sepsis models with systemic UC-MSC administration were included. Meta-analyses were conducted and expressed as odds ratios (OR) and ratios of the weighted means with 95% CI for categorical and continuous data, respectively. Risk of bias was assessed with the SYRCLE tool.

RESULTS

Twenty-six studies (34 experiments, n = 1258 animals) were included in this review. Overall mortality was significantly reduced with UC-MSC treatment as compared to controls (OR: 0.26, 95% CI: 0.18-0.36). At various prespecified time intervals, UC-MSCs reduced surrogate measures of organ dysfunction related to the kidney, liver, and lung; reduced coagulopathy and endothelial permeability; and enhanced pathogen clearance from multiple sites. UC-MSCs also modulated systemic inflammatory mediators. No studies were rated as low risk across all SYCLE domains.

CONCLUSIONS

These results demonstrate the efficacy of UC-MSC treatment in preclinical sepsis models and highlight their potential as a therapeutic intervention for septic shock.

A phase II dose evaluation pilot feasibility randomized controlled trial of cholecalciferol in critically ill children with vitamin D deficiency (VITdAL-PICU study)

BACKGROUND

Vitamin D deficiency (VDD) is highly prevalent in the pediatric intensive care unit (ICU) and associated with worse clinical course. Trials in adult ICU demonstrate rapid restoration of vitamin D status using an enteral loading dose is safe and may improve outcomes. There have been no published trials of rapid normalization of VDD in the pediatric ICU.

METHODS

We conducted a multicenter placebo-controlled phase II pilot feasibility randomized clinical trial from 2016 to 2017. We randomized 67 critically ill children with VDD from ICUs in Canada, Chile and Austria using a 2:1 randomization ratio to receive a loading dose of enteral cholecalciferol (10,000 IU/kg, maximum of 400,000 IU) or placebo. Participants, care givers, and outcomes assessors were blinded. The primary objective was to determine whether the loading dose normalized vitamin D status (25(OH)D > 75 nmol/L). Secondary objectives were to evaluate for adverse events and assess the feasibility of a phase III trial.

RESULTS

Of 67 randomized participants, one was withdrawn and seven received more than one dose of cholecalciferol before the protocol was amended to a single loading dose, leaving 59 participants in the primary analyses (40 treatment, 19 placebo). Thirty-one/38 (81.6%) participants in the treatment arm achieved a plasma 25(OH)D concentration > 75 nmol/L versus 1/18 (5.6%) the placebo arm. The mean 25(OH)D concentration in the treatment arm was 125.9 nmol/L (SD 63.4). There was no evidence of vitamin D toxicity and no major drug or safety protocol violations. The accrual rate was 3.4 patients/month, supporting feasibility of a larger trial. A day 7 blood sample was collected for 84% of patients. A survey administered to 40 participating families showed that health-related quality of life (HRQL) was the most important outcome for families for the main trial (30, 75%).

CONCLUSIONS

A single 10,000 IU/kg dose can rapidly and safely normalize plasma 25(OH)D concentrations in critically ill children with VDD, but with significant variability in 25(OH)D concentrations. We established that a phase III multicentre trial is feasible. Using an outcome collected after hospital discharge (HRQL) will require strategies to minimize loss-to-follow-up.

TRIAL REGISTRATION

CLINICALTRIALS

gov NCT02452762 Registered 25/05/2015.

Anemia and Red Blood Cell Transfusion in Aneurysmal Subarachnoid Hemorrhage

Anemia is very common in aneurysmal subarachnoid hemorrhage (aSAH), with approximately half of the aSAH patient population developing moderate anemia during their hospital stay. The available evidence (both physiologic and clinical) generally supports an association of anemia with unfavorable outcomes. Although aSAH shares a number of common mechanisms of secondary insult with other forms of acute brain injury, aSAH also has specific features that make it unique: an early phase (in which early brain injury predominates) and a delayed phase (in which delayed cerebral ischemia and vasospasm predominate). The effects of both anemia and transfusion are potentially variable between these phases, which may have unique considerations and possibly different risk-benefit profiles. Data on transfusion in this population are almost exclusively limited to observational studies, which suffer from significant heterogeneity and risk of bias. Overall, the results are conflicting, with the balance of the studies suggesting that transfusion is associated with unfavorable outcomes. The transfusion targets that are well established in other critically ill populations should not be automatically applied to patients with aSAH because of the unique disease characteristics of this population and the limited representation of aSAH in the clinical trials that established these targets. There are two upcoming clinical trials evaluating transfusion in aSAH that should help clarify specific transfusion targets. Until then, it is reasonable to base transfusion decisions on the current guidelines and use an individualized approach incorporating physiologic and clinical data when available.

Association of age with death and withdrawal of life-sustaining therapy after severe traumatic brain injury

BACKGROUND

Compared to younger age, older age (≥ 65 yr) is associated with worse outcomes after severe traumatic brain injury (TBI). We sought to describe the association of older age with in-hospital death and aggressiveness of intervention.

METHODS

We conducted a retrospective cohort study of adult (age ≥ 16 yr) patients with severe TBI admitted to a single academic tertiary care neurotrauma centre between January 2014 and December 2015. We collected data through chart review as well as from our institutional administrative database. We provided descriptive statistics and used multivariable logistic regression to evaluate the independent association of age with the primary outcome, in-hospital death. The secondary outcome was early withdrawal of life-sustaining therapy.

RESULTS

There were 126 adult patients (median age 67 yr [Q1-Q3, 33-80 yr]) with severe TBI during the study period who met our eligibility criteria. The most common mechanism was high-velocity blunt injury (55 patients [43.6%]). The median Marshall score was 4 (Q1-Q3, 2-6), and the median Injury Severity Score was 26 (Q1-Q3, 25-35). After controlling for confounders including clinical frailty, pre-existing comorbidity, injury severity, Marshall score and neurologic examination at admission, we observed that older patients were more likely than younger patients to die in hospital (odds ratio 5.10, 95% confidence interval 1.65-15.78). Older patients were also more likely to experience early withdrawal of life-sustaining therapy and less likely to receive invasive interventions.

CONCLUSION

After controlling for confounding factors relevant to older patients, we observed that age was an important and independent predictor of in-hospital death and early withdrawal of life-sustaining therapy. The mechanism by which age influences clinical decision-making independent of global and neurologic injury severity, clinical frailty and comorbidities remains unclear.

Mesenchymal stem cells induce dynamic immunomodulation of airway and systemic immune cells in vivo but do not improve survival for mice with H1N1 virus-induced acute lung injury

Introduction: Influenza A virus (IAV)-induced acute lung injury (ALI) is characterized by pronounced proinflammatory activation and respiratory lung dysfunction. In this study, we performed deep immune profiling on airway and circulating immune cells to examine the effect of immunomodulation and therapeutic outcomes of mesenchymal stem cells (MSCs) therapy in mice with IAV-induced ALI. Methods: Animals were inoculated intranasally with H1N1 IAV, followed by intravenous administration of vehicle, or human clinical-grade, bone marrow-derived MSCs 24-h later, and monitored for six days to evaluate the survival. In another set of animals, bronchoalveolar lavage (BAL) fluid and whole blood were collected three days after infection for flow or mass cytometry (CyTOF) immune profiling analysis. Results: Immune cell population and phenotypic shifts in blood were mapped by CyTOF. Increases were observed in granulocytes and myeloid-derived cells in blood from vehicle-treated animals. While MSC treatment accentuated changes in these populations, naïve B, antibody-secreting B cells, and T cells were decreased in MSC-treated animals at day 3. Compared to sham animals, IAV infection induced a significant 5.5-fold increase in BAL total cell counts, including CD4⁺ and CD8⁺ T cells, CD19⁺ B cells, CD11b + Ly6G + neutrophils, and CD11b + Ly6C + monocytes. MSC treatment significantly decreased BAL total cell counts in IAV-infected mice, specifically the number of infiltrating CD4⁺ T cells and CD11b + Ly6G + neutrophils. In contrast, there were increases in CD8⁺ T cells, B cells, and monocytes in the alveolar space in MSC-treated animals. Phenotypic immune cell profiling of blood and BAL revealed a significantly higher proportion of the monocyte population with the M2 phenotype (CD206) in MSC-treated animals; however, this failed to confer protective effects in the survival of infected mice or reduce viral titer in the lung. Further investigation revealed that MSCs were susceptible to IAV infection, leading to increased cell death and potentially affecting their efficacy. Conclusion: These findings provided in vivo evidence that MSCs promote the selective recruitment of immune cells to the site of infection during IAV infection, with reductions in proinflammatory phenotypes. However, MSCs offered no survival benefit in IAV-infected animals, possibly due to MSCs' H1N1 IAV susceptibility and subsequent cell death.

Diagnostic accuracy of ancillary tests for death by neurologic criteria: a systematic review and meta-analysis

PURPOSE

Ancillary tests are frequently used in death determination by neurologic criteria (DNC), particularly when the clinical neurologic examination is unreliable. Nevertheless, their diagnostic accuracy has not been extensively studied. Our objective was to synthesize the sensitivity and specificity of commonly used ancillary tests for DNC.

SOURCE

We performed a systematic review and meta-analysis by searching MEDLINE, EMBASE, Cochrane databases, and CINAHL Ebsco from their inception to 4 February 2022. We selected cohort and case-control studies including patients with 1) clinically diagnosed death by neurologic criteria or 2) clinically suspected death by neurologic criteria who underwent ancillary testing for DNC. We excluded studies without a priori diagnostic criteria and studies conducted solely on pediatric patients. Accepted reference standards were clinical examination, four-vessel conventional angiography, and radionuclide imaging. Data were directly extracted from published reports. We assessed the methodological quality of studies with the QUADAS-2 tool and estimated ancillary test sensitivities and specificities using hierarchical Bayesian models with diffuse priors.

PRINCIPAL FINDINGS

Overall, 137 records met the selection criteria. One study (0.7%) had a low risk of bias in all QUADAS-2 domains. Among clinically diagnosed death by neurologic criteria patients (n = 8,891), ancillary tests had similar pooled sensitivities (range, 0.82-0.93). Sensitivity heterogeneity was greater within (σ = 0.10-0.15) than between (σ = 0.04) ancillary test types. Among clinically suspected death by neurologic criteria patients (n = 2,732), pooled ancillary test sensitivities ranged between 0.81 and 1.00 and specificities between 0.87 and 1.00. Most estimates had high statistical uncertainty.

CONCLUSION

Studies assessing ancillary test diagnostic accuracy have an unclear or high risk of bias. High-quality studies are required to thoroughly validate ancillary tests for DNC.

STUDY REGISTRATION

PROSPERO (CRD42013005907); registered 7 October 2013.

Patient Relevance of the Modified Rankin Scale in Subarachnoid Hemorrhage Research: An International Cross-sectional Survey

BACKGROUND AND OBJECTIVES

There is significant heterogeneity in the reporting of outcomes measure in aneurysmal subarachnoid hemorrhage (aSAH) research. The modified Rankin Scale (mRS) is the most commonly reported functional outcome measure. The mRS focuses on physical disability, however many aSAH survivors experience sequalae in other domains, and the mRS may therefore not capture outcomes important to aSAH survivors. The objective of this study was to assess the clinical relevance of the mRS as a research outcome measure to people with lived aSAH.

METHODS

We conducted an international cross-sectional survey of 355 aSAH survivors, family members and caregivers to evaluate patient-perceived outcomes in relation to the mRS. The mRS was assessed using a previously validated web-based tool.

RESULTS

Response rate was 60%; respondents from 7 continents were comprised of 86% aSAH survivors and 14% family members/caregivers. Agreement between self-assessed outcome and the mRS was poor (Kappa 0.26 (CI 0.14-0.39)). Of the 172 respondents who self-assessed as having had a good aSAH outcome, 122 (71%) had a score of 0-2 on the mRS. 19% of respondents with a good outcome, based on a measured mRS score of 0-2, self-assessed as having had a poor aSAH outcome. When the mRS score was dichotomized as 0-3 corresponding to a good outcome, agreement between the score and self-assessed outcome remained poor with a Kappa score of 0.40 (CI 0.20-0.60). Thirty per cent of respondents felt that the mRS should not be used as an outcome measure in future aSAH trials.

DISCUSSION

The findings suggest that there is poor agreement between aSAH survivors' self-assessed outcome, their actual mRS score and the dichotomization of the mRS score into good/poor outcomes. Patient-centered and -informed outcome measurement tools are needed to guide the aSAH research agenda.

Comparison of freshly cultured versus cryopreserved mesenchymal stem cells in animal models of inflammation: A pre-clinical systematic review

Background:

Mesenchymal stem cells (MSCs) are multipotent cells that demonstrate therapeutic potential for the treatment of acute and chronic inflammatory-mediated conditions. Although controversial, some studies suggest that MSCs may lose their functionality with cryopreservation which could render them non-efficacious. Hence, we conducted a systematic review of comparative pre-clinical models of inflammation to determine if there are differences in in vivo measures of pre-clinical efficacy (primary outcomes) and in vitro potency (secondary outcomes) between freshly cultured and cryopreserved MSCs.

Methods:

A systematic search on OvidMEDLINE, EMBASE, BIOSIS, and Web of Science (until January 13, 2022) was conducted. The primary outcome included measures of in vivo pre-clinical efficacy; secondary outcomes included measures of in vitro MSC potency. Risk of bias was assessed by the SYRCLE ‘Risk of Bias’ assessment tool for pre-clinical studies.

Results:

Eighteen studies were included. A total of 257 in vivo pre-clinical efficacy experiments represented 101 distinct outcome measures. Of these outcomes, 2.3% (6/257) were significantly different at the 0.05 level or less; 2 favoured freshly cultured and 4 favoured cryopreserved MSCs. A total of 68 in vitro experiments represented 32 different potency measures; 13% (9/68) of the experiments were significantly different at the 0.05 level or less, with seven experiments favouring freshly cultured MSC and two favouring cryopreserved MSCs.

Conclusions:

The majority of preclinical primary in vivo efficacy and secondary in vitro potency outcomes were not significantly different (p<0.05) between freshly cultured and cryopreserved MSCs. Our systematic summary of the current evidence base may provide MSC basic and clinical research scientists additional rationale for considering a cryopreserved MSC product in their pre-clinical studies and clinical trials as well as help identify research gaps and guide future related research.

Funding:

Ontario Institute for Regenerative Medicine

Poly(I:C) Enhances Mesenchymal Stem Cell Control of Myeloid Cells From COVID-19 Patients

Mesenchymal stem cells (MSCs) are being studied for the treatment of COVID-19-associated critical illness, due to their immunomodulatory properties. Here, we hypothesized that viral mimic-priming improves MSCs’ abilities to rebalance the dysregulated immune responses in COVID-19. Transcriptome analysis of poly(I:C)-primed MSCs (pIC-MSCs) showed upregulation of pathways in antiviral and immunomodulatory responses. Together with increased expression of antiviral proteins such as MX1, IFITM3, and OAS1, these changes translated to greater effector functions in regulating monocytes and granulocytes while further enhancing MSCs’ ability to block SARS-CoV-2 pseudovirus entry into epithelial cells. Most importantly, the addition of pIC-MSCs to COVID-19 patient whole blood significantly reduced inflammatory neutrophils and increased M2 monocytes while enhancing their phagocytic effector function. We reveal for the first time that MSCs can be primed by Toll-like receptor 3 agonist to improve their ability to rebalance the dysregulated immune responses seen in severe SARS-CoV-2 infection.

•

Viral stimuli mimic enhances MSC’s antiviral and immunomodulatory molecular profile

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pIC-primed MSCs inhibit SARS-CoV2 pseudovirus entry into epithelial cells

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pIC-MSCs recalibrate dysregulated cellular response in COVID patient’s whole blood

Clinical evaluation and ancillary testing for the diagnosis of death by neurologic criteria: a cross-sectional survey of Canadian intensivists

PURPOSE

Trust in the deceased organ donation process relies on the expectation that the diagnosis of death by neurologic criteria (DNC) is accurate and reliable. The objective of this study was to assess the perceptions and approaches to DNC diagnosis among Canadian intensivists.

METHODS

We conducted a self-administered, online, cross-sectional survey of Canadian intensivists. Our sampling frame included all intensivists practicing in Canadian institutions. Results are reported using descriptive statistics.

RESULTS

Among 550 identified intensivists, 249 (45%) completed the survey. Respondents indicated they would be comfortable diagnosing DNC based on clinical criteria alone in cases where there is movement in response to stimulation (119/248; 48%); inability to evaluate upper/lower extremity responses (84/249; 34%); spontaneous peripheral movement (76/249; 31%); inability to evaluate both oculocephalic and oculo-caloric reflexes (40/249; 16%); presence of high cervical spinal cord injury (40/249; 16%); and within 24 hr of hypoxemic-ischemic brain injury (38/247; 15%). Most respondents agreed that an ancillary test should always be conducted when a complete clinical evaluation is impossible (225/241; 93%); when there is possibility of a residual sedative effect (216/242; 89%); when the mechanism for brain injury is unclear (172/241; 71%); and if isolated brainstem injury is suspected (142/242; 59%). Sixty-six percent (158/241) believed that ancillary tests are sensitive and 55% (132/241) that they are specific for DNC. Respondents considered the following ancillary tests useful for DNC: four-vessel conventional angiography (211/241; 88%), nuclear imaging (179/240; 75%), computed tomography (CT) angiography (156/240; 65%), and CT perfusion (134/240; 56%).

CONCLUSION

There is variability in perceptions and approaches to DNC diagnosis among Canadian intensivists, and some practices are inconsistent with national recommendations.

Balanced Versus Unbalanced Fluid in Critically Ill Children: Systematic Review and Meta-Analysis

OBJECTIVES

The ideal crystalloid fluid bolus therapy for fluid resuscitation in children remains unclear, but pediatric data are limited. Administration of 0.9% saline has been associated with hyperchloremic metabolic acidosis and acute kidney injury. The primary objective of this systematic review was to compare the effect of balanced versus unbalanced fluid bolus therapy on the mean change in serum bicarbonate or pH within 24 hours in critically ill children.

DATA SOURCES

We searched MEDLINE including Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Embase, CENTRAL Trials Registry of the Cochrane Collaboration, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform.

STUDY SELECTION

Using the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols guidelines, we retrieved all controlled trials and observational cohort studies comparing balanced and unbalanced resuscitative fluids in critically ill children. The primary outcome was the change in serum bicarbonate or blood pH. Secondary outcomes included the prevalence of hyperchloremia, acute kidney injury, renal replacement therapy, and mortality.

DATA EXTRACTION

Study screening, inclusion, data extraction, and risk of bias assessments were performed independently by two authors.

DATA SYNTHESIS

Among 481 references identified, 13 met inclusion criteria. In the meta-analysis of three randomized controlled trials with a population of 162 patients, we found a greater mean change in serum bicarbonate level (pooled estimate 1.60 mmol/L; 95% CI, 0.04-3.16; p = 0.04) and pH level (pooled mean difference 0.03; 95% CI, 0.00-0.06; p = 0.03) after 4-12 hours of rehydration with balanced versus unbalanced fluids. No differences were found in chloride serum level, acute kidney injury, renal replacement therapy, or mortality.

CONCLUSIONS

Our systematic review found some evidence of improvement in blood pH and bicarbonate values in critically ill children after 4-12 hours of fluid bolus therapy with balanced fluid compared with the unbalanced fluid. However, a randomized controlled trial is needed to establish whether these findings have an impact on clinical outcomes before recommendations can be generated.

Intravenous albumin for the prevention of hemodynamic instability during sustained low-efficiency dialysis: a randomized controlled feasibility trial (The SAFER-SLED Study)

Background

Hemodynamic instability is a frequent complication of sustained low-efficiency dialysis (SLED) treatments in the ICU. Intravenous hyperoncotic albumin may prevent hypotension and facilitate ultrafiltration. In this feasibility trial, we sought to determine if a future trial, powered to evaluate clinically relevant outcomes, is feasible.

Methods

This single-center, blinded, placebo-controlled, randomized feasibility trial included patients with acute kidney injury who started SLED in the ICU. Patients were randomized to receive 25% albumin versus 0.9% saline (control) as 100 mL boluses at the start and midway through SLED, for up to 10 sessions. The recruitment rate and other feasibility outcomes were determined. Secondary exploratory outcomes included ultrafiltration volumes and metrics of hemodynamic instability.

Results

Sixty patients (271 SLED sessions) were recruited over 10 months. Age and severity of illness were similar between study groups. Most had septic shock and required vasopressor support at baseline. Protocol adherence occurred for 244 sessions (90%); no patients were lost to follow-up; no study-related adverse events were observed; open label albumin use was 9% and 15% in the albumin and saline arms, respectively. Ultrafiltration volumes were not significantly different. Compared to the saline group, the albumin group experienced less hemodynamic instability across all definitions assessed including a smaller absolute decrease in systolic blood pressure (mean difference 10.0 mmHg, 95% confidence interval 5.2–14.8); however, there were significant baseline differences in the groups with respect to vasopressor use prior to SLED sessions (80% vs 61% for albumin and saline groups, respectively).

Conclusions

The efficacy of using hyperoncotic albumin to prevent hemodynamic instability in critically ill patients receiving SLED remains unclear. A larger trial to evaluate its impact in this setting, including evaluating clinically relevant outcomes, is feasible.

Trial registration ClinicalTrials.gov (NCT03665311); First Posted: Sept 11th, 2018. https://clinicaltrials.gov/ct2/show/NCT03665311?term=NCT03665311&draw=2&rank=1

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-021-00962-x.

Effect of prenotification on the response rate of a postal survey of emergency physicians: a randomised, controlled, assessor-blind trial

OBJECTIVES

Response rates to physician surveys are typically low. The objective of this study was to determine the effect of a prenotification letter on the response rate of a postal survey of emergency physicians.

DESIGN

This was a substudy of a national, cross-sectional postal survey sent to emergency physicians in Canada. We randomised participants to either receive a postal prenotification letter prior to the survey, or to no prenotification letter.

PARTICIPANTS

A random sample of 500 emergency physicians in Canada. Participants were selected from the Canadian Medical Directory, a national medical directory which lists more than 99% of practising physicians in Canada.

INTERVENTIONS

Using computer-generated randomisation, physicians were randomised in a concealed fashion to receive a prenotification letter approximately 1 week prior to the survey, or to not receive a prenotification letter. All physicians received an unconditional incentive of a $3 coffee card with the survey instrument. In both groups, non-respondents were sent reminder surveys approximately every 14 days and a special contact using Xpresspost during the final contact attempt.

OUTCOME

The primary outcome was the survey response rate.

RESULTS

201 of 447 eligible physicians returned the survey (45.0%). Of 231 eligible physicians contacted in the prenotification group, 80 (34.6%) returned the survey and among 237 eligible physicians contacted in the no-prenotification group, 121 (51.1%) returned the survey (absolute difference in proportions 16.5%, 95% CI 2.5 to 30.5, p=0.01).

CONCLUSION

Inclusion of a prenotification letter resulted in a lower response rate in this postal survey of emergency physicians. Given the added costs, time and effort required to send a prenotification letter, this study suggests that it may be more effective to omit the prenotification letter in physician postal surveys.

Effect of Probiotics on Incident Ventilator-Associated Pneumonia in Critically Ill Patients: A Randomized Clinical Trial

IMPORTANCE

Growing interest in microbial dysbiosis during critical illness has raised questions about the therapeutic potential of microbiome modification with probiotics. Prior randomized trials in this population suggest that probiotics reduce infection, particularly ventilator-associated pneumonia (VAP), although probiotic-associated infections have also been reported.

OBJECTIVE

To evaluate the effect of Lactobacillus rhamnosus GG on preventing VAP, additional infections, and other clinically important outcomes in the intensive care unit (ICU).

DESIGN, SETTING, AND PARTICIPANTS

Randomized placebo-controlled trial in 44 ICUs in Canada, the United States, and Saudi Arabia enrolling adults predicted to require mechanical ventilation for at least 72 hours. A total of 2653 patients were enrolled from October 2013 to March 2019 (final follow-up, October 2020).

INTERVENTIONS

Enteral L rhamnosus GG (1 × 1010 colony-forming units) (n = 1321) or placebo (n = 1332) twice daily in the ICU.

MAIN OUTCOMES AND MEASURES

The primary outcome was VAP determined by duplicate blinded central adjudication. Secondary outcomes were other ICU-acquired infections including Clostridioides difficile infection, diarrhea, antimicrobial use, ICU and hospital length of stay, and mortality.

RESULTS

Among 2653 randomized patients (mean age, 59.8 years [SD], 16.5 years), 2650 (99.9%) completed the trial (mean age, 59.8 years [SD], 16.5 years; 1063 women [40.1%.] with a mean Acute Physiology and Chronic Health Evaluation II score of 22.0 (SD, 7.8) and received the study product for a median of 9 days (IQR, 5-15 days). VAP developed among 289 of 1318 patients (21.9%) receiving probiotics vs 284 of 1332 controls (21.3%; hazard ratio [HR], 1.03 (95% CI, 0.87-1.22; P = .73, absolute difference, 0.6%, 95% CI, -2.5% to 3.7%). None of the 20 prespecified secondary outcomes, including other ICU-acquired infections, diarrhea, antimicrobial use, mortality, or length of stay showed a significant difference. Fifteen patients (1.1%) receiving probiotics vs 1 (0.1%) in the control group experienced the adverse event of L rhamnosus in a sterile site or the sole or predominant organism in a nonsterile site (odds ratio, 14.02; 95% CI, 1.79-109.58; P < .001).

CONCLUSIONS AND RELEVANCE

Among critically ill patients requiring mechanical ventilation, administration of the probiotic L rhamnosus GG compared with placebo, resulted in no significant difference in the development of ventilator-associated pneumonia. These findings do not support the use of L rhamnosus GG in critically ill patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02462590.

How well do critical care audit and feedback interventions adhere to best practice? Development and application of the REFLECT-52 evaluation tool

BACKGROUND

Healthcare Audit and Feedback (A&F) interventions have been shown to be an effective means of changing healthcare professional behavior, but work is required to optimize them, as evidence suggests that A&F interventions are not improving over time. Recent published guidance has suggested an initial set of best practices that may help to increase intervention effectiveness, which focus on the "Nature of the desired action," "Nature of the data available for feedback," "Feedback display," and "Delivering the feedback intervention." We aimed to develop a generalizable evaluation tool that can be used to assess whether A&F interventions conform to these suggestions for best practice and conducted initial testing of the tool through application to a sample of critical care A&F interventions.

METHODS

We used a consensus-based approach to develop an evaluation tool from published guidance and subsequently applied the tool to conduct a secondary analysis of A&F interventions. To start, the 15 suggestions for improved feedback interventions published by Brehaut et al. were deconstructed into rateable items. Items were developed through iterative consensus meetings among researchers. These items were then piloted on 12 A&F studies (two reviewers met for consensus each time after independently applying the tool to four A&F intervention studies). After each consensus meeting, items were modified to improve clarity and specificity, and to help increase the reliability between coders. We then assessed the conformity to best practices of 17 critical care A&F interventions, sourced from a systematic review of A&F interventions on provider ordering of laboratory tests and transfusions in the critical care setting. Data for each criteria item was extracted by one coder and confirmed by a second; results were then aggregated and presented graphically or in a table and described narratively.

RESULTS

In total, 52 criteria items were developed (38 ratable items and 14 descriptive items). Eight studies targeted lab test ordering behaviors, and 10 studies targeted blood transfusion ordering. Items focused on specifying the "Nature of the Desired Action" were adhered to most commonly-feedback was often presented in the context of an external priority (13/17), showed or described a discrepancy in performance (14/17), and in all cases it was reasonable for the recipients to be responsible for the change in behavior (17/17). Items focused on the "Nature of the Data Available for Feedback" were adhered to less often-only some interventions provided individual (5/17) or patient-level data (5/17), and few included aspirational comparators (2/17), or justifications for specificity of feedback (4/17), choice of comparator (0/9) or the interval between reports (3/13). Items focused on the "Nature of the Feedback Display" were reported poorly-just under half of interventions reported providing feedback in more than one way (8/17) and interventions rarely included pilot-testing of the feedback (1/17 unclear) or presentation of a visual display and summary message in close proximity of each other (1/13). Items focused on "Delivering the Feedback Intervention" were also poorly reported-feedback rarely reported use of barrier/enabler assessments (0/17), involved target members in the development of the feedback (0/17), or involved explicit design to be received and discussed in a social context (3/17); however, most interventions clearly indicated who was providing the feedback (11/17), involved a facilitator (8/12) or involved engaging in self-assessment around the target behavior prior to receipt of feedback (12/17).

CONCLUSIONS

Many of the theory-informed best practice items were not consistently applied in critical care and can suggest clear ways to improve interventions. Standardized reporting of detailed intervention descriptions and feedback templates may also help to further advance research in this field. The 52-item tool can serve as a basis for reliably assessing concordance with best practice guidance in existing A&F interventions trialed in other healthcare settings, and could be used to inform future A&F intervention development.

TRIAL REGISTRATION

Not applicable.

Surrogate Humane Endpoints in Small Animal Models of Acute Lung Injury: A Modified Delphi Consensus Study of Researchers and Laboratory Animal Veterinarians

OBJECTIVES

In many jurisdictions, ethical concerns require surrogate humane endpoints to replace death in small animal models of acute lung injury. Heterogenous selection and reporting of surrogate endpoints render interpretation and generalizability of findings between studies difficult. We aimed to establish expert-guided consensus among preclinical scientists and laboratory animal veterinarians on selection and reporting of surrogate endpoints, monitoring of these models, and the use of analgesia.

DESIGN

A three-round consensus process, using modified Delphi methodology, with researchers who use small animal models of acute lung injury and laboratory animal veterinarians who provide care for these animals. Statements on the selection and reporting of surrogate endpoints, monitoring, and analgesia were generated through a systematic search of MEDLINE and Embase. Participants were asked to suggest any additional potential statements for evaluation.

SETTING

A web-based survey of participants representing the two stakeholder groups (researchers, laboratory animal veterinarians). Statements were rated on level of evidence and strength of support by participants. A final face-to-face meeting was then held to discuss results.

SUBJECTS

None.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Forty-two statements were evaluated, and 29 were rated as important, with varying strength of evidence. The majority of evidence was based on rodent models of acute lung injury. Endpoints with strong support and evidence included temperature changes and body weight loss. Behavioral signs and respiratory distress also received support but were associated with lower levels of evidence. Participants strongly agreed that analgesia affects outcomes in these models and that none may be necessary following nonsurgical induction of acute lung injury. Finally, participants strongly supported transparent reporting of surrogate endpoints. A prototype composite score was also developed based on participant feedback.

CONCLUSIONS

We provide a preliminary framework that researchers and animal welfare committees may adapt for their needs. We have identified knowledge gaps that future research should address.

Neuromuscular blocking agents in acute respiratory distress syndrome: updated systematic review and meta-analysis of randomized trials

Purpose

Existing clinical practice guidelines support the use of neuromuscular blocking agents (NMBA) in acute respiratory distress syndrome (ARDS); however, a recent large randomized clinical trial (RCT) has questioned this practice. Therefore, we updated a previous systematic review to determine the efficacy and safety of NMBAs in ARDS.

Methods

We searched MEDLINE, EMBASE (October 2012 to July 2019), the Cochrane (Central) database, and clinical trial registries (ClinicalTrials.gov, ISRCTN Register, and WHO ICTRP) for RCTs comparing the effects of NMBA as a continuous infusion versus placebo or no NMBA infusion (but allowing intermittent NMBA boluses) on patient-important outcomes for adults with ARDS. Two independent reviewers assessed the methodologic quality of the primary studies and abstracted data.

Results

Seven RCTs, including four new RCTs, met eligibility criteria for this review. These trials enrolled 1598 patients with moderate to severe ARDS at centers in the USA, France, and China. All trials assessed short-term continuous infusions of cisatracurium or vecuronium. The pooled estimate for mortality outcomes showed significant statistical heterogeneity, which was only explained by a subgroup analysis by depth of sedation in the control arm. A continuous NMBA infusion did not improve mortality when compared to a light sedation strategy with no NMBA infusion (relative risk [RR] 0.99; 95% CI 0.86–1.15; moderate certainty; P = 0.93). On the other hand, continuous NMBA infusion reduced mortality when compared to deep sedation with as needed NMBA boluses (RR 0.71; 95% CI 0.57–0.89; low certainty; P = 0.003). Continuous NMBA infusion reduced the rate of barotrauma (RR 0.55; 95% CI 0.35–0.85, moderate certainty; P = 0.008) across eligible trials, but the effect on ventilator-free days, duration of mechanical ventilation, and ICU-acquired weakness was uncertain.

Conclusions

Inconsistency in study methods and findings precluded the pooling of all trials for mortality. In a pre-planned sensitivity analysis, the impact of NMBA infusion on mortality depends on the strategy used in the control arm, showing reduced mortality when compared to deep sedation, but no effect on mortality when compared to lighter sedation. In both situations, a continuous NMBA infusion may reduce the risk of barotrauma, but the effects on other patient-important outcomes remain unclear. Future research, including an individual patient data meta-analysis, could help clarify some of the observed findings in this updated systematic review.

Prevention of post-cardiac surgery vitamin D deficiency in children with congenital heart disease: a pilot feasibility dose evaluation randomized controlled trial

Background

The vast majority of children undergoing cardiac surgery have low vitamin D levels post-operative, which may contribute to greater illness severity and worse clinical outcomes. Prior to the initiation of a large phase III clinical trial focused on clinical outcomes, studies are required to evaluate the feasibility of the study protocol, including whether the proposed dosing regimen can safely prevent post-operative vitamin D deficiency in this high-risk population.

Methods

We conducted a two-arm, double-blind dose evaluation randomized controlled trial in children requiring cardiopulmonary bypass for congenital heart disease. Pre-operatively, participants were randomized to receive cholecalciferol representing usual care (< 1 year = 400 IU/day, > 1 year = 600 IU/day) or a higher dose approximating the Institute of Medicine tolerable upper intake level (< 1 year = 1600 IU/day, > 1 year = 2400 IU/day). The feasibility outcomes were post-operative vitamin D status (primary), vitamin D-related adverse events, accrual rate, study withdrawal rate, blinding, and protocol non-adherence.

Results

Forty-six children were randomized, and five withdrew prior to surgery, leaving 41 children (21 high dose, 20 usual care) in the final analysis. The high dose group had higher 25-hydroxyvitamin D concentrations both intraoperatively (mean difference + 25.9 nmol/L; 95% CI 8.3–43.5) and post-operatively (mean difference + 17.2 nmol/L; 95% CI 5.5–29.0). Fewer participants receiving high-dose supplementation had post-operative serum 25-hydroxyvitamin D concentrations under 50 nmol/L, compared with usual care (RR 0.31, 95% CI 0.11–0.87). Post-operative vitamin D status was associated with the treatment arm and the number of doses received. There were no cases of hypercalcemia, and no significant adverse events related to vitamin D. While only 75% of the target sample size was recruited (limited funding), the consent rate (83%), accrual rate (1.5 per site month), number of withdrawals (11%), and ability to maintain blinding support feasibility of a larger trial.

Conclusions

Pre-operative daily high-dose supplementation improved vitamin D status pre-operatively and at time of pediatric ICU admission. The protocol for a more definitive trial should limit enrollment of children with at least 30 days between randomization and surgery to allow adequate duration of supplementation or consider a loading dose.

Trial registration

ClinicalTrials.gov, NCT01838447. Registered on April 24, 2013

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial

IMPORTANCE

Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited.

OBJECTIVE

To determine whether hydrocortisone improves outcome for patients with severe COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020.

INTERVENTIONS

The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108).

MAIN OUTCOMES AND MEASURES

The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%).

RESULTS

After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively.

CONCLUSIONS AND RELEVANCE

Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02735707.

Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial

IMPORTANCE

Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited.

OBJECTIVE

To determine whether hydrocortisone improves outcome for patients with severe COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020.

INTERVENTIONS

The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (n = 143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (n = 152), or no hydrocortisone (n = 108).

MAIN OUTCOMES AND MEASURES

The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%).

RESULTS

After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (n = 137), shock-dependent (n = 146), and no (n = 101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively.

CONCLUSIONS AND RELEVANCE

Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02735707.

Survey of Canadian critical care physicians' knowledge and attitudes towards legislative aspects of the deceased organ donation system

PURPOSE

We surveyed Canadian critical care physicians who may care for patients who are potential organ donors to understand their attitudes and knowledge of legislation governing the deceased organ donation system.

METHODS

We used a web-based, self-administered survey that included questions related to opt-out consent and mandatory referral legislation. Potential participants were identified through membership lists of professional societies and manual searches. We designed our survey using standardized methods and administered it in February and March 2018.

RESULTS

Fifty percent (263/529) of potential participants completed the questionnaire. A majority (61%; 144/235) supported a change towards an opt-out consent model, and 77% (181/235) stated they believe it would increase donation rates. Asked if opt-out consent would change their practices, 71% (166/235) stated an opt-out model would not change how or if they approach families to discuss donation. Fifty-six percent (139/249) supported mandatory referral laws, while only 42% (93/219) of those working in provinces with mandatory referral correctly stated that such laws exist in their province. Respondents gave variable responses on who should be accountable when patients are not referred, and 16% (40/249) believed no one should be held accountable.

CONCLUSIONS

While a majority of critical care physicians supported opt-out consent and mandatory referral, many were neutral or against it. Many were unaware of existing laws and had variable opinions on how to ensure accountability. Efforts to increase understanding of how legislative models influence practice are required for any law to achieve its desired effect.

An international comparison of the cost of fluid resuscitation therapies

OBJECTIVE

Fluid resuscitation is a ubiquitous intervention in the management of patients treated in the intensive care unit, which has implications for intensive care unit resourcing and budgets. Our objective was to calculate the relative cost of resuscitation fluids in several countries to inform future economic evaluations.

METHODS

We collected site-level data regarding the availability and cost of fluids as part of an international survey. We normalised costs to net present values using purchasing power parities and published inflation figures. Costs were also adjusted for equi-effective dosing based on intravascular volume expansion effectiveness and expressed as US dollars (USD) per 100 mL crystalloid equivalent.

RESULTS

A total of 187 sites had access to cost data. Between countries, there was an approximate six fold variation in the cost of crystalloids and colloids overall. The average cost for crystalloids overall was less than 1 USD per 100 mL. In contrast, colloid fluids had higher average costs (59 USD per 100 mL). After adjusting for equi-effective dosing, saline was ∼27 times less costly than albumin (saline: 0.6 USD per 100 mL crystalloid equivalent; albumin 4-5%: 16.4 USD; albumin 20-25%: 15.8 USD) and ∼4 times less costly than hydroxyethyl starch solution (saline: 0.6 USD; hydroxyethyl starch solution: 2.5 USD). Buffered salt solutions, such as compound sodium acetate solutions (e.g., Plasmalyte®), had the highest average cost of crystalloid fluids, costing between 3 and 4 USD per 100 mL.

CONCLUSION

The cost of fluid varies substantially between fluid types and between countries, although normal (0.9%) saline is consistently less costly than colloid preparations and some buffered salt solutions. These data can be used to inform future economic evaluations of fluid preparations.

Comparison of freshly cultured versus freshly thawed (cryopreserved) mesenchymal stem cells in preclinical in vivo models of inflammation: a protocol for a preclinical systematic review and meta-analysis

BACKGROUND

Mesenchymal stem cells (MSCs) are multipotent cells that demonstrate therapeutic potential for the treatment of acute and chronic inflammatory-mediated conditions. Especially for acute conditions, it is critical to have a readily available freshly thawed (cryopreserved) MSC product for rapid administration. Although controversial, some studies suggest that MSCs may lose their functionality with cryopreservation which in turn could render them non-efficacious.

OBJECTIVE

In controlled preclinical in vivo models of inflammation, to determine if there are differences in surrogate measures of preclinical efficacy between freshly cultured and freshly thawed MSCs METHODS/DESIGN: A systematic search for pre-clinical in vivo inflammatory model studies will compare freshly cultured to freshly thawed MSCs from any source. The primary outcomes will include measures of in vivo preclinical efficacy; secondary outcomes will include measures of in vitro MSC potency. Electronic searches for MEDLINE and EMBASE will be constructed and reviewed by the Peer Review of Electronic Search Strategies (PRESS) process. If applicable, study outcomes will be meta-analyzed using a random effects model. Risk of bias will be assessed by the SYRCLE "Risk of Bias" assessment tool for preclinical in vivo studies.

DISCUSSION

The results of this systematic review will provide translational scientists, clinical trialists, health regulators, and the clinical and public community with the current pre-clinical evidence base related to the efficacy and potency of freshly cultured versus freshly thawed MSCs, help identify evidence gaps, and guide future related research.

SYSTEMATIC REVIEW REGISTRATION

Protocol is submitted to PROSPERO for registration (pending confirmation) and will be submitted to Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADES) for public posting.

External validation demonstrated the Ottawa SAH prediction models can identify pSAH using health administrative data

OBJECTIVES

The objective of the study is to externally validate three primary subarachnoid hemorrhage (pSAH) identification models.

STUDY DESIGN AND SETTING

We evaluated three models that identify pSAH using recursive partitioning (A), logistic regression (B), and a prevalence-adjusted logistic regression(C), respectively. Blinded chart review and/or linkage to existing registries determined pSAH status. We included all patients aged ≥18 in four participating center registries or whose discharge abstracts contained ≥1 administrative codes of interest between January 1, 2012 and December 31, 2013.

RESULTS

A total of 3,262 of 193,190 admissions underwent chart review (n = 2,493) or registry linkage (n = 769). A total of 657 had pSAH confirmed (20·1% sample, 0·34% admissions). The sensitivity, specificity, and positive predictive value (PPV) were as follows: i) model A: 98·3% (97·0-99·2), 53·5% (51·5-55·4), and 34·8% (32·6-37·0); ii) model B (score ≥6): 98·0% (96·6-98·9), 47·4% (45·5-49·4), and 32·0% (30·0-34·1); and iii) model C (score ≥2): 95·7% (93·9-97·2), 85·5% (84·0-86·8), and 62·3 (59·3-65·3), respectively. Model C scores of 0, 1, 2, 3, or 4 had probabilities of 0·5% (0·2-1·5), 1·5% (1·0-2·2), 24·8% (21·0-29·0), 90·0% (86·8-92·0), and 97·8% (88·7-99·6), without significant difference between centers (P = 0·86). The PPV of the International Classification of Diseases code (I60) was 63·0% (95% confidence interval: 60·0-66·0).

CONCLUSIONS

All three models were highly sensitive for pSAH. Model C could be used to adjust for misclassification bias.

Audit and feedback to improve laboratory test and transfusion ordering in critical care: a systematic review

BACKGROUND

Laboratory tests and transfusions are sometimes ordered inappropriately, particularly in the critical care setting, which sees frequent use of both. Audit and Feedback (A&F) is a potentially useful intervention for modifying healthcare provider behaviors, but its application to the complex, team-based environment of critical care is not well understood. We conducted a systematic review of the literature on A&F interventions for improving test or transfusion ordering in the critical care setting.

METHODS

Five databases, two registries, and the bibliographies of relevant articles were searched. We included critical care studies that assessed the use of A&F targeting healthcare provider behaviors, alone or in combination with other interventions to improve test and transfusion ordering, as compared to historical practice, no intervention, or another healthcare behaviour change intervention. Studies were included only if they reported laboratory test or transfusion orders, or the appropriateness of orders, as outcomes. There were no restrictions based on study design, date of publication, or follow-up time. Intervention characteristics and absolute differences in outcomes were summarized. The quality of individual studies was assessed using a modified version of the Effective Practice and Organisation of Care Cochrane Review Group's criteria.

RESULTS

We identified 16 studies, including 13 uncontrolled before-after studies, one randomized controlled trial, one controlled before-after study, and one controlled clinical trial (quasi-experimental). These studies described 17 interventions, mostly (88%) multifaceted interventions with an A&F component. Feedback was most often provided in a written format only (41%), more than once (53%), and most often only provided data aggregated to the group-level (41%). Most studies saw a change in the hypothesized direction, but not all studies provided statistical analyses to formally test improvement. Overall study quality was low, with studies often lacking a concurrent control group.

CONCLUSIONS

Our review summarizes characteristics of A&F interventions implemented in the critical care context, points to some mechanisms by which A&F might be made more effective in this setting, and provides an overview of how the appropriateness of orders was reported. Our findings suggest that A&F can be effective in the context of critical care; however, further research is required to characterize approaches that optimize the effectiveness in this setting alongside more rigorous evaluation methods.

TRIAL REGISTRATION

PROSPERO CRD42016051941.

Survey of Canadian intensivists on physician non-referral and family override of deceased organ donation

PURPOSE

Intensive care physicians play an important role in the identification and referral of potential organ donors in Canada. Nevertheless, little is known about intensivists' attitudes or behaviours in situations where families override previously expressed consent to donate; nor why physicians elect not to refer patients who are potential donors to provincial organ donation organizations (physician non-referral).

METHODS

We integrated questions regarding family override and physician non-referral into an online, self-administered survey of Canadian intensivists. We report results descriptively.

RESULTS

Fifty percent of targeted respondents (n = 550) participated. Fifty-five percent reported having witnessed family override situations and 44% reported having personally not referred patients who were potential donors. Fifty-six percent of respondents stated they would not pursue donation in the face of family override; 2% stated they would continue with the donation process. Fear of loss of trust in the donation system (81%) and obligation to respect the grief and desires of surrogate decision makers (71%) were frequently reported reasons to respect family override requests. Respondents who chose not to refer patients often did so based on organ dysfunction they assumed would preclude donation (59%), or a perception that the family was too distressed to consider donation (42%). No respondents reported that personally held beliefs against organ donation influenced their decision.

CONCLUSION

Physicians caring for patients who are potential organ donors commonly encounter both family override and physician non-referral situations. Knowledge translation of optimal practices in identification and referral could help ensure that physician practices align with legal requirements and practice recommendations.

Cell therapy with intravascular administration of mesenchymal stromal cells continues to appear safe: An updated systematic review and meta-analysis

BACKGROUND

Characterization of the mesenchymal stromal cell (MSC) safety profile is important as this novel therapy continues to be evaluated in clinical trials for various inflammatory conditions. Due to an increase in published randomized controlled trials (RCTs) from 2012-2019, we performed an updated systematic review to further characterize the MSC safety profile.

METHODS

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and Web of Science (to May 2018) were searched. RCTs that compared intravascular delivery of MSCs to controls in adult populations were included. Pre-specified adverse events were grouped according to: (1) immediate, (2) infection, (3) thrombotic/embolic, and (4) longer-term events (mortality, malignancy). Adverse events were pooled and meta-analyzed by fitting inverse-variance binary random effects models. Primary and secondary clinical efficacy endpoints were summarized descriptively.

FINDINGS

7473 citations were reviewed and 55 studies met inclusion criteria (n = 2696 patients). MSCs as compared to controls were associated with an increased risk of fever (Relative Risk (RR) = 2·48, 95% Confidence Interval (CI) = 1·27-4·86; I2 = 0%), but not non-fever acute infusional toxicity, infection, thrombotic/embolic events, death, or malignancy (RR = 1·16, 0·99, 1·14, 0·78, 0·93; 95% CI = 0·70-1·91, 0·81-1·21, 0·67-1·95, 0·65-0·94, 0·60-1·45; I2 = 0%, 0%, 0%, 0%, 0%). No included trials were ended prematurely due to safety concerns.

INTERPRETATIONS

MSC therapy continues to exhibit a favourable safety profile. Future trials should continue to strengthen study rigor, reporting of MSC characterization, and adverse events.

FUNDING

Stem Cell Network, Ontario Institute for Regenerative Medicine and Ontario Research Fund.

A pilot randomized controlled trial of 7 versus 14 days of antibiotic treatment for bloodstream infection on non-intensive care versus intensive care wards

BACKGROUND

The optimal treatment duration for patients with bloodstream infection is understudied. The Bacteremia Antibiotic Length Actually Needed for Clinical Effectiveness (BALANCE) pilot randomized clinical trial (RCT) determined that it was feasible to enroll and randomize intensive care unit (ICU) patients with bloodstream infection to 7 versus 14 days of treatment, and served as the vanguard for the ongoing BALANCE main RCT. We performed this BALANCE-Ward pilot RCT to examine the feasibility and impact of potentially extending the BALANCE main RCT to include patients hospitalized on non-ICU wards.

METHODS

We conducted an open pilot RCT among a subset of six sites participating in the ongoing BALANCE RCT, randomizing patients with positive non-Staphylococcus aureus blood cultures on non-ICU wards to 7 versus 14 days of antibiotic treatment. The co-primary feasibility outcomes were recruitment rate and adherence to treatment duration protocol. We compared feasibility outcomes, patient/pathogen characteristics, and overall outcomes among those enrolled in this BALANCE-Ward and prior BALANCE-ICU pilot RCTs. We estimated the sample size and non-inferiority margin impacts of expanding the BALANCE main RCT to include non-ICU patients.

RESULTS

A total of 134 patients were recruited over 47 site-months (mean 2.9 patients/site-month, median 1.0, range 0.1-4.4 patients/site-month). The overall recruitment rate exceeded the BALANCE-ICU pilot RCT (mean 1.10 patients/site-month, p < 0.0001). Overall protocol adherence also exceeded the adherence in the BALANCE-ICU pilot RCT (125/134, 93% vs 89/115, 77%, p = 0.0003). BALANCE-Ward patients were older, with lower Sequential Organ Failure Assessment scores, and higher proportions of infections caused by Escherichia coli and genito-urinary sources of bloodstream infection. The BALANCE-Ward pilot RCT patients had an overall 90-day mortality rate of 17/133 (12.8%), which was comparable to the 90-day mortality rate in the ICU pilot RCT (17/115, 14.8%) (p = 0.65). Simulation models indicated there would be minimal sample size and non-inferiority margin implications of expanding enrolment to increasing proportions of non-ICU versus ICU patients.

CONCLUSION

It is feasible to enroll non-ICU patients in a trial of 7 versus 14 days of antibiotics for bloodstream infection, and expanding the BALANCE RCT hospital-wide has the potential to improve the timeliness and generalizability of trial results.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT02917551. Registered on September 28, 2016.

A Systematic Review of the Impact of Surgical Special Care Units on Patient Outcomes and Health Care Resource Utilization

Perioperative intermediate care units (termed surgical special care units) have been widely implemented across health systems because they are believed to improve surveillance and management of high-risk surgical patients. Our objective was to conduct a systematic review to investigate the effects of a 3-level model of perioperative care delivery (ie, ward, surgical special care unit, or intensive care unit) compared to a 2-level model of care (ie, ward, intensive care unit) on postoperative outcomes. Our protocol was registered with PROSPERO, the international prospective register of systematic reviews (CRD42015025155). Randomized controlled studies and nonrandomized comparator studies were included. We performed a systematic search of Medline, Cumulative Index to Nursing and Allied Health Literature, Embase, and the Cochrane library (inception - 11/2017). The primary outcome was mortality; secondary outcomes included length of stay and hospital costs. We identified 1995 citations with our search, and 21 studies met eligibility criteria (2 randomized controlled studies and 19 nonrandomized comparator studies; 44,134 patients in total). Surgical special care units were characterized by continuous monitoring (12 studies), the absence of mechanical ventilation (8 studies), nurse-to-patient ratios (range, 1:2-1:4), and number of beds (median: 5; range: 3-33). Thirteen studies reported on mortality. Notable findings included no observed difference in overall in-hospital mortality, but an apparent increase in intensive care unit mortality in a 3-level model of care. This may reflect a decanting of lower acuity patients from the intensive care unit to the surgical special care unit. No significant difference was found in hospital length of stay; however, 2 studies demonstrated reductions in hospital costs with the implementation of a surgical special care unit. Significant clinical and methodological heterogeneity precluded pooled analysis. Given the prevalence of surgical special care units, the results of our review suggest that additional methodologically rigorous investigations are needed to understand the effect of these units on the surgical population.

Choice of crystalloid fluid in the treatment of hyperglycemic emergencies: a systematic review protocol

BACKGROUND

Diabetic ketoacidosis (DKA) and hyperglycemic hyperosmolar state (HHS) are life-threatening complications of diabetes mellitus which require prompt treatment with large volume crystalloid fluid administration. A variety of crystalloid fluids is currently available for use and differs in their composition and ion concentrations. While there are potential pros and cons for different crystalloid fluids, it remains unknown if any particular fluid confers a clinical outcome benefit over others in the treatment of hyperglycemic emergencies.

METHODS

A systematic search of MEDLINE, Embase, and the Cochrane Library of Systematic Reviews will be conducted to identify eligible studies, which will include observational and interventional studies involving adult and pediatric patients admitted to the hospital with either DKA or HHS. The interventions will include intravenous treatment with 0.9% saline versus other buffered (Ringer's lactate, Hartmann's, etc.), and non-buffered (0.45% saline) crystalloid fluids. The primary outcome is mortality at the latest follow-up time point. Secondary outcomes will include mortality at specific time points, length of hospital stay, development of acute kidney injury, requirement for renal replacement therapy, altered level of consciousness, and the time to normalization of several serum biochemical parameters. Where appropriate, meta-analyses will be performed for the outcomes and conducted separately for adult and pediatric patient populations.

DISCUSSION

DKA and HHS are dangerous complications of diabetes mellitus and account for significant morbidity and mortality. Given the importance of crystalloid fluid administration in the management of these conditions, a systematic synthesis of the existing evidence base will identify potential evidence gaps and may help guide future clinical practice.

Impact of balanced versus unbalanced fluid resuscitation on clinical outcomes in critically ill children: protocol for a systematic review and meta-analysis

BACKGROUND

Isotonic crystalloid fluid bolus therapy is used in critically ill children to restore or maintain hemodynamic stability. However, the ideal choice of crystalloid remains to be determined. The most easily available and most frequently used crystalloid is 0.9% saline, an unbalanced crystalloid, that has been associated with hyperchloremic metabolic acidosis and acute kidney injury (AKI). Balanced fluids such as Ringer's lactate (RL) were developed to be closer to the composition of serum. However, they are more expensive and less readily available than 0.9% saline. Few trials have found RL to be associated with more favorable outcomes, but pediatric data is limited and inconsistent. The objective of the present systematic review is to review existing literature to determine the effect of balanced versus unbalanced fluid bolus therapy on metabolic acidosis in critically ill children.

METHODS

Using the Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) guidelines, we will conduct a systematic review to retrieve all controlled trials and observational studies comparing balanced and unbalanced resuscitative fluids in critically ill children from age 28 days to 18 years old in any resuscitation settings. Search strategy was developed in collaboration with an experienced clinical research librarian. The primary outcome is the incidence and/or time to resolution of metabolic acidosis. Secondary outcomes included the incidence of hyperchloremia, AKI, duration of renal replacement therapy, vasopressors, mechanical ventilation, total volume of rehydration needed per day, extracorporeal membrane oxygenation, and length of stay and mortality. Study screening, inclusion, data extraction, and assessment of risk of bias will be performed independently by two authors. We intend to perform a meta-analysis with studies that are compatible on the basis of population and outcomes.

DISCUSSION

Isotonic crystalloid fluid bolus therapy is a ubiquitous treatment in resuscitation of critically ill pediatric patients and yet there is no clear recommendation to support the choice of balanced versus unbalanced fluid. The present review will summarize current available data in the literature and assess whether recommendations can be generated regarding the choice of crystalloids or otherwise identify knowledge gaps which will open the door to a large-scale randomized controlled trial (RCT).

Saline versus albumin fluid for extracorporeal removal with slow low-efficiency dialysis (SAFER-SLED): study protocol for a pilot trial

Background

Critically ill patients frequently develop acute kidney injury that necessitates renal replacement therapy (RRT). At some centers, critically ill patients who are hemodynamically unstable and require RRT are treated with slow low-efficiency dialysis (SLED). Unfortunately, hypotension is a frequent complication that occurs during SLED treatments and may limit the recovery of kidney function. Hypotension may also limit the amount of fluid that can be removed by ultrafiltration with SLED. Fluid overload can be exacerbated as a consequence, and fluid overload is associated with increased mortality.

Occasionally, intravenous albumin fluid is given to prevent or treat low blood pressure during SLED. The intent of doing so is to increase the colloid oncotic pressure in the circulation to draw in extravascular fluid, increase the blood pressure, and enable more aggressive fluid removal with ultrafiltration. Nonetheless, there is little evidence to support this practice and theoretical reasons why it may not be especially effective at augmenting fluid removal in critically ill patients. At the same time, albumin fluid is expensive.

As such, we present a protocol for a study to assess the feasibility of a randomized controlled trial evaluating the use of albumin fluid versus saline in critically ill patients receiving SLED.

Methods

This study is a single-center, double-blind, and randomized controlled pilot trial with two parallel arms. It involves randomly assigning patients receiving SLED treatment in the ICU to receive either albumin (25%) boluses or normal saline fluid boluses (placebo) to prevent and treat low blood pressure.

Discussion

The results of this pilot trial will help with planning a larger trial comparing the efficacy of the interventions in achieving fluid removal in critically ill patients with AKI on SLED. They will establish whether enough participants would participate in a larger study and accept the study procedures.

Trial registration

This trial is registered on ClinicalTrials.gov Identifier NCT03665311, registered on September 11, 2018.

Electronic supplementary material

The online version of this article (10.1186/s40814-019-0460-3) contains supplementary material, which is available to authorized users.

Regenerative cell therapy for pulmonary arterial hypertension in animal models: a systematic review

Background

Pulmonary arterial hypertension (PAH) is a rare disease characterized by widespread loss of the pulmonary microcirculation and elevated pulmonary arterial pressures leading to pathological right ventricular remodeling and ultimately right heart failure. Regenerative cell therapies could potentially restore the effective lung microcirculation and provide a curative therapy for PAH. The objective of this systematic review was to compare the efficacy of regenerative cell therapies in preclinical models of PAH.

Methods

A systematic search strategy was developed and executed. We included preclinical animal studies using regenerative cell therapy in experimental models of PAH. Primary outcomes were right ventricular systolic pressure (RVSP) and mean pulmonary arterial pressure (mPAP). The secondary outcome was right ventricle/left ventricle + septum weight ratio (RV/LV+S). Pooled effect sizes were undertaken using random effects inverse variance models. Risk of bias and publication bias were assessed.

Results

The systematic search yielded 1285 studies, of which 44 met eligibility criteria. Treatment with regenerative cell therapy was associated with decreased RVSP (SMD − 2.10; 95% CI − 2.59 to − 1.60), mPAP (SMD − 2.16; 95% CI − 2.97 to − 1.35), and RV/LV+S (SMD − 1.31, 95% CI − 1.64 to − 0.97). Subgroup analysis demonstrated that cell modification resulted in greater reduction in RVSP. The effects on RVSP and mPAP remained statistically significant even after adjustment for publication bias. The majority of studies had an unclear risk of bias.

Conclusions

Preclinical studies of regenerative cell therapy demonstrated efficacy in animal models of PAH; however, future studies should consider incorporating design elements to reduce the risk of bias.

Systematic review registration

Suen CM, Zhai A, Lalu MM, Welsh C, Levac BM, Fergusson D, McIntyre L and Stewart DJ. Efficacy and safety of regenerative cell therapy for pulmonary arterial hypertension in animal models: a preclinical systematic review protocol. Syst Rev. 2016;5:89.

Trial registration

CAMARADES-NC3Rs Preclinical Systematic Review & Meta-analysis Facility (SyRF). http://syrf.org.uk/protocols/. Syst Rev 5:89, 2016

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1172-6) contains supplementary material, which is available to authorized users.

Do patient-reported outcome measures for SAH include patient, family, and caregiver priorities? A scoping review

OBJECTIVE

To systematically describe literature that identified patient/family/caregiver priorities for subarachnoid hemorrhage (SAH)-specific patient-reported outcome measures (PROMs), developed novel SAH PROMs by incorporating patient/family/caregiver perspectives, or involved patient/family/caregiver perspectives in evaluating existing SAH PROMs.

METHODS

We conducted a scoping review using Embase and Ovid MEDLINE from inception to February 6, 2018. Study eligibility and data extraction was performed independently and in duplicate. For each eligible citation, we abstracted information about study population, design, type of patient involvement, and outcome measures. We planned a descriptive summary of all included studies.

RESULTS

Our search yielded 4,961 citations, of which 15 met our eligibility criteria. Four of these included duplicate data, so our final sample consisted of 12 articles. There were 879 patients with SAH and 241 carers from the 11/12 articles that reported these data. One additional study involved 70 individuals but did not specify the number of carers or patients. We did not find any studies where SAH survivors or their families were directly involved in the full continuum of PROM outcome conceptualization from development to evaluation. We found 41 measures identified by patients with SAH. We identified only 2 PROMs developed with patients and only one that was a post hoc evaluation by patients. These 3 PROMs are subarachnoid hemorrhage outcome tool, Wessex Patient Carer Questionnaire, and Functional Status Examination, respectively.

CONCLUSION

We identified 3 PROMs that have involved patients in some way, but the extent to which they reflect patient priorities remains unclear. More work is needed to ensure SAH research is not overlooking outcomes that are important to patients.

Stakeholder views regarding ethical issues in the design and conduct of pragmatic trials: study protocol

Background

Randomized controlled trial (RCT) trial designs exist on an explanatory-pragmatic spectrum, depending on the degree to which a study aims to address a question of efficacy or effectiveness. As conceptualized by Schwartz and Lellouch in 1967, an explanatory approach to trial design emphasizes hypothesis testing about the mechanisms of action of treatments under ideal conditions (efficacy), whereas a pragmatic approach emphasizes testing effectiveness of two or more available treatments in real-world conditions. Interest in, and the number of, pragmatic trials has grown substantially in recent years, with increased recognition by funders and stakeholders worldwide of the need for credible evidence to inform clinical decision-making. This increase has been accompanied by the onset of learning healthcare systems, as well as an increasing focus on patient-oriented research. However, pragmatic trials have ethical challenges that have not yet been identified or adequately characterized. The present study aims to explore the views of key stakeholders with respect to ethical issues raised by the design and conduct of pragmatic trials. It is embedded within a large, four-year project that seeks to develop guidance for the ethical design and conduct of pragmatic trials. As a first step, this study will address important gaps in the current empirical literature with respect to identifying a comprehensive range of ethical issues arising from the design and conduct of pragmatic trials. By opening up a broad range of topics for consideration within our parallel ethical analysis, we will extend the current debate, which has largely emphasized issues of consent, to the range of ethical considerations that may flow from specific design choices.

Methods

Semi-structured interviews with key stakeholders (e.g. trialists, methodologists, lay members of study teams, bioethicists, and research ethics committee members), across multiple jurisdictions, identified based on their known experience and/or expertise with pragmatic trials.

Discussion

We expect that the study outputs will be of interest to a wide range of knowledge users including trialists, ethicists, research ethics committees, journal editors, regulators, healthcare policymakers, research funders and patient groups. All publications will adhere to the Tri-Agency Open Access Policy on Publications.

Electronic supplementary material

The online version of this article (10.1186/s12910-018-0332-z) contains supplementary material, which is available to authorized users.

Caloric intake and the fat-to-carbohydrate ratio in hypercapnic acute respiratory failure: Post-hoc analysis of the PermiT trial

BACKGROUND

The effect of moderate caloric enteral intake in critically ill patients with hypercapnic acute respiratory failure (HCARF) is unclear. We studied the impact of permissive underfeeding (PUF) compared with standard feeding (SF) on various HCARF outcomes.

MATERIALS AND METHODS

The PermiT trial randomized 894 patients to either PUF (40-60% caloric requirement) or SF (70-100% requirement) with similar protein intake and found no difference in mortality, mechanical ventilation (MV) duration and ventilator-free days. In this post-hoc study, we restricted analysis to mechanically-ventilated patients with HCARF (PaCO₂ >45 mmHg on the first two study days) and assessed the impact of trial interventions and fat-to-carbohydrate ratio on outcomes.

RESULTS

One-hundred-twenty patients had HCARF (59 PUF and 61 SF, age 53.7 ± 17.8 years, body mass index 31.1 ± 11.2 kg/m², Acute Physiology and Chronic Health Evaluation II score 21.7 ± 7.1 and day-1 PaCO₂ 61 ± 16 mmHg). Caloric intake was 815 ± 270 kcal/day in PUF group and 1289 ± 407 kcal/day in SF group. The two groups had similar PaCO₂ levels during ICU stay. The 90-day mortality (33.9% versus 35.6%, p = 0.85), MV duration (10.7 ± 6.8 versus 11.1 ± 8.1 days, p = 0.56) and ventilator-free days (52.9 ± 38.6 versus 51.2 ± 38.0 days, p = 0.80) were also similar in PUF and SF groups, respectively. Ventilator-free days and 90-day mortality were similar when the fat-to-carbohydrate ratio was < or ≥ the median value (0.73) in all patients and in PUF and SF groups.

CONCLUSIONS

In patients with HCARF, SF and PUF were associated with similar PaCO₂, MV duration, ventilator-free days and mortality. Fat-to-carbohydrate ratio was not associated with mortality or ventilator-free days.

TRIAL REGISTRATION

ISRCTN Registry: ISRCTN68144998.

Association of protein intake with the outcomes of critically ill patients: a post hoc analysis of the PermiT trial

Background

The optimal amount of protein intake in critically ill patients is uncertain.

Objective

In this post hoc analysis of the PermiT (Permissive Underfeeding vs. Target Enteral Feeding in Adult Critically Ill Patients) trial, we tested the hypothesis that higher total protein intake was associated with lower 90-d mortality and improved protein biomarkers in critically ill patients.

Design

In this post hoc analysis of the PermiT trial, we included patients who received enteral feeding for ≥3 consecutive days. Using the median protein intake of the cohort as a cutoff, patients were categorized into 2 groups: a higher-protein group (>0.80 g · kg-1 · d-1) and a lower-protein group (≤0.80 g · kg-1 · d-1). We developed a propensity score for receiving higher protein. Primary outcome was 90-d mortality. We also compared serial values of prealbumin, transferrin, 24-h urinary nitrogen, and 24-h nitrogen balance on days 1, 7, and 14.

Results

Among the 729 patients included in this analysis, the average protein intake was 0.8 ± 0.3 g · kg-1 · d-1 [1.0 ± 0.2 g · kg-1 · d-1 in the higher-protein group (n = 365) and 0.6 ± 0.2 g · kg-1 · d-1 in the lower-protein group (n = 364); P < 0.0001]. There was no difference in 90-d mortality between the 2 groups [88/364 (24.2%) compared with 94/363 (25.9%), propensity score-adjusted OR: 0.80; 95% CI: 0.56, 1.16; P = 0.24]. Higher protein intake was associated with an increase in 24-h urea nitrogen excretion compared with lower protein intake, but without a significant change in prealbumin, transferrin, or 24-h nitrogen balance.

Conclusions

In the PermiT trial, a moderate difference in protein intake was not associated with lower mortality. Higher protein intake was associated with increased nitrogen excretion in the urine without a corresponding change in prealbumin, transferrin, or nitrogen balance. Protein intake needs to be tested in adequately powered randomized controlled trials targeting larger differences in protein intake in high-risk populations.

Developing a framework for the ethical design and conduct of pragmatic trials in healthcare: a mixed methods research protocol

Background

There is a widely recognized need for more pragmatic trials that evaluate interventions in real-world settings to inform decision-making by patients, providers, and health system leaders. Increasing availability of electronic health records, centralized research ethics review, and novel trial designs, combined with support and resources from governments worldwide for patient-centered research, have created an unprecedented opportunity to advance the conduct of pragmatic trials, which can ultimately improve patient health and health system outcomes. Such trials raise ethical issues that have not yet been fully addressed, with existing literature concentrating on regulations in specific jurisdictions rather than arguments grounded in ethical principles. Proposed solutions (e.g. using different regulations in “learning healthcare systems”) are speculative with no guarantee of improvement over existing oversight procedures. Most importantly, the literature does not reflect a broad vision of protecting the core liberty and welfare interests of research participants. Novel ethical guidance is required. We have assembled a team of ethicists, trialists, methodologists, social scientists, knowledge users, and community members with the goal of developing guidance for the ethical design and conduct of pragmatic trials.

Methods

Our project will combine empirical and conceptual work and a consensus development process. Empirical work will: (1) identify a comprehensive list of ethical issues through interviews with a small group of key informants (e.g. trialists, ethicists, chairs of research ethics committees); (2) document current practices by reviewing a random sample of pragmatic trials and surveying authors; (3) elicit views of chairs of research ethics committees through surveys in Canada, UK, USA, France, and Australia; and (4) elicit views and experiences of community members and health system leaders through focus groups and surveys. Conceptual work will consist of an ethical analysis of identified issues and the development of new ethical solutions, outlining principles, policy options, and rationales. The consensus development process will involve an independent expert panel to develop a final guidance document.

Discussion

Planned output includes manuscripts, educational materials, and tailored guidance documents to inform and support researchers, research ethics committees, journal editors, regulators, and funders in the ethical design and conduct of pragmatic trials.

Safety and Efficacy of Adult Stem Cell Therapy for Acute Myocardial Infarction and Ischemic Heart Failure (SafeCell Heart): A Systematic Review and Meta-Analysis

Preclinical and clinical evidence suggests that mesenchymal stem cells (MSCs) may be beneficial in treating both acute myocardial infarction (AMI) and ischemic heart failure (IHF). However, the safety profile and efficacy of MSC therapy is not well‐known. We conducted a systematic review of clinical trials that evaluated the safety or efficacy of MSCs for AMI or IHF. Embase, PubMed/Medline, and Cochrane Central Register of Controlled Trials were searched from inception to September 27, 2017. Studies that examined the use of MSCs administered to adults with AMI or IHF were eligible. The Cochrane risk of bias tool was used to assess bias of included studies. The primary outcome was safety assessed by adverse events and the secondary outcome was efficacy which was assessed by mortality and left ventricular ejection fraction (LVEF). A total of 668 citations were reviewed and 23 studies met eligibility criteria. Of these, 11 studies evaluated AMI and 12 studies evaluated IHF. There was no association between MSCs and acute adverse events. There was a significant improvement in overall LVEF in patients who received MSCs (SMD 0.73, 95% CI 0.24–1.21). No significant difference in mortality was noted (Peto OR 0.68, 95% CI 0.38–1.22). Results from our systematic review suggest that MSC therapy for ischemic heart disease appears to be safe. There is a need for a well‐designed adequately powered randomized control trial (with rigorous adverse event reporting and evaluations of cardiac function) to further establish a clear risk‐benefit profile of MSCs. Stem Cells Translational Medicine2018;7:857–866

The Ottawa SAH search algorithms: protocol for a multi- centre validation study of primary subarachnoid hemorrhage prediction models using health administrative data (the SAHepi prediction study protocol)

Background

Conducting prospective epidemiological studies of hospitalized patients with rare diseases like primary subarachnoid hemorrhage (pSAH) are difficult due to time and budgetary constraints. Routinely collected administrative data could remove these barriers. We derived and validated 3 algorithms to identify hospitalized patients with a high probability of pSAH using administrative data. We aim to externally validate their performance in four hospitals across Canada.

Methods

Eligible patients include those ≥18 years of age admitted to these centres from January 1, 2012 to December 31, 2013. We will include patients whose discharge abstracts contain predictive variables identified in the models (ICD-10-CA diagnostic codes I60** (subarachnoid hemorrhage), I61** (intracranial hemorrhage), 162** (other nontrauma intracranial hemorrhage), I67** (other cerebrovascular disease), S06** (intracranial injury), G97 (other postprocedural nervous system disorder) and CCI procedural codes 1JW51 (occlusion of intracranial vessels), 1JE51 (carotid artery inclusion), 3JW10 (intracranial vessel imaging), 3FY20 (CT scan (soft tissue of neck)), and 3OT20 (CT scan (abdominal cavity)). The algorithms will be applied to each patient and the diagnosis confirmed via chart review. We will assess each model’s sensitivity, specificity, negative and positive predictive value across the sites.

Discussion

Validating the Ottawa SAH Prediction Algorithms will provide a way to accurately identify large SAH cohorts, thereby furthering research and altering care.

FLUID trial: a protocol for a hospital-wide open-label cluster crossover pragmatic comparative effectiveness randomised pilot trial

INTRODUCTION

0.9% saline and Ringer's lactate are the two most common resuscitation crystalloid fluids. 0.9% saline may lead to hyperchloraemic metabolic acidosis and may be associated with impaired kidney function and death. Few large multicentre randomised trials have been conducted to evaluate the effect of these two fluids on clinically important outcomes.

METHODS

FLUID is a pragmatic pilot cluster randomised crossover trial in which four hospitals will be randomised to normal saline or Ringer's lactate for 14 weeks, then crossover to the alternative fluid for the subsequent 14 weeks after 1 to 3 week transition. With waiver of informed consent, all adult and paediatric patients admitted to participating sites will be included in the FLUID trial except for neonates. Primary feasibility outcome is study fluid protocol adherence (target:≥80%). Secondary feasibility outcomes include time to research ethics board (REB) approval and readiness to trial initiation (≤3 months from REB submission and approval). Primary (composite of death or re-admission to hospital in first 90 days of index hospitalisation) and secondary clinical outcomes for the future large FLUID trial will be described. Protocol adherence will be collected by site at specified time points. All clinical data will be obtained at patient level through provincial health administrative data held at the Institute for Clinical Evaluative Sciences (ICES). Event rates for the primary and secondary outcomes will be described using frequencies and proportions with 95% CIs. Intracluster and interperiod correlation coefficients will be calculated from population-level data available at ICES.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Ottawa Health Science Research Ethics Board. The FLUID pilot will determine feasibility, and ICES data across all potential sites in Ontario will allow calculation of sample size parameter estimates to inform the design and implementation of the large trial.

TRIAL REGISTRATION NUMBER

NCT02721485; Pre-results.

Comparison of crystalloid resuscitation fluids for treatment of acute brain injury: a clinical and pre-clinical systematic review and network meta-analysis protocol

BACKGROUND

Current guidelines identify the choice of fluid resuscitation as important in minimizing the incidence of secondary brain injury from cerebral edema. It is widely accepted that isotonic crystalloid resuscitation fluids, specifically normal saline (NS), are optimal for resuscitation and that other relatively hypotonic fluids, such as Ringer's lactate (RL), should be avoided in this patient population. The aim of this review is to systematically compare the use of relatively hypotonic versus isotonic crystalloid resuscitation fluids in clinical and pre-clinical models of acute brain injury and their effect on outcomes. In recognition of the potential need for a network meta-analysis (NMA), we have also included all other relevant crystalloid resuscitation fluids as interventions of relevance to potentially inform indirect comparisons.

METHODS

Systematic searches of MEDLINE, Embase, and Web of Science BIOSIS Previews® will be used to identify eligible clinical and pre-clinical studies, which included studies examining acute brain injury (human and in vivo animal brain injury models) within the first 7 days of therapy. The intervention of interest is the intravenous use of relatively hypotonic crystalloid resuscitation fluids (e.g., Ringer's lactate, Hartmann's or Plasma Lyte® fluids). The main comparator of interest is an isotonic crystalloid resuscitation fluid, specifically normal saline (0.9%). Other crystalloid resuscitation fluids (e.g., hypertonic saline (3-23.4%)) will also be included as an additional intervention of interest. The primary outcome measures of interest are intracranial pressure (ICP) and cerebral perfusion pressure (CPP). Secondary outcomes include the effect of resuscitation on cerebral edema, brain and serum osmolarity, and electrolyte concentrations and clinical outcomes including modified Rankin Scale (mRS), (extended) Glasgow Outcome Scale (GOS/eGOS), and mortality. Separate meta-analyses will be conducted to quantify the effects of the different fluid resuscitation on acute brain injury outcomes in clinical and pre-clinical populations. Network meta-analyses to compare interventions will also be performed to compare the effects of different interventions.

DISCUSSION

This systematic review will comprehensively summarize the difference in treatment efficacy of various crystalloid resuscitation fluids in acute brain injury. This review is essential to underscore the evidence, or lack thereof, present in the literature to date to support current preference-driven practice and to direct future study.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO #CRD42016042960.

Random serum free cortisol and total cortisol measurements in pediatric septic shock

Background The aim of the study was to examine the relationship between serum total cortisol (TC) and free cortisol (FC) levels in children with septic shock and the relationship of these levels with baseline illness severity. Methods A sub-study of a randomized controlled trial (RCT) of hydrocortisone vs. placebo in pediatric septic shock conducted in seven academic pediatric intensive care units (PICUs) in Canada on children aged newborn to 17 years. Thirty children with septic shock had serum sent for TC and FC measurement within 6 h of meeting the study eligibility criteria. Results Baseline FC and TC levels were strongly correlated with baseline Pediatric Risk of Mortality (PRISM) score (R2=0.759, p<0.001; R2=0.717, p<0.001) and moderately correlated with admission Vasotropic Inotropic Score (VIS) (R2=0.489, p<0.001; R2=0.316, p<0.001). Serum TC levels were highly correlated with FC levels (R2=0.92, p<0.001) and showed strong agreement (R2=0.98, p<0.001 on a Bland-Altman plot). The ratio of FC to TC moderately correlated with TC levels (R2=0.46, p<0.001) but did not correlate with baseline albumin levels (R2=0.19, p=0.13). Conclusions Random TC and FC levels are strongly correlated, show strong agreement and are reflective of illness severity in children with septic shock. As such, isolated FC measurement does not appear to provide added information relative to TC in acutely ill children with septic shock.

Anemia prevalence and incidence and red blood cell transfusion practices in aneurysmal subarachnoid hemorrhage: results of a multicenter cohort study

Background

Whether a restrictive strategy for red blood cell (RBC) transfusion is applied to patients with aneurysmal subarachnoid hemorrhage (aSAH) is unclear. To inform the design and conduct of a future clinical trial, we sought to describe transfusion practices, hemoglobin (Hb) triggers, and predictors of RBC transfusion in patients with aSAH.

Methods

This is a retrospective cohort study of all consecutively admitted adult patients with aSAH at four tertiary care centers from January 1, 2012, to December 31, 2013. Patients were identified from hospital administrative discharge records and existing local aSAH databases. Data collection by trained abstractors included demographic data, aSAH characteristics, Hb and transfusion data, other major aSAH cointerventions, and outcomes using a pretested case report form with standardized procedures. Descriptive statistics were used to summarize data, and regression models were used to identify associations between anemia, transfusion, and other relevant predictors and outcome.

Results

A total of 527 patients met inclusion eligibility. Mean (±SD) age was 57 ± 13 years, and 357 patients (67.7%) were female. The median modified Fisher grade was 4 (IQR 3–4). Mean nadir Hb was 98 ± 20 g/L and occurred on median admission day 4 (IQR 2–11). RBC transfusion occurred in 100 patients (19.0%). Transfusion rates varied across centers (12.1–27.4%, p = 0.02). Patients received a median of 1 RBC unit (IQR 1–2) per transfusion episode and a median total of 2 units (IQR 1–4). Median pretransfusion Hb for first transfusion was 79 g/L (IQR 74–93) and did not vary substantially across centers (78–82 g/L, p = 0.37). Of patients with nadir Hb < 80 g/L, 66.3% received a transfusion compared with 2.0% with Hb nadir ≥ 100 g/L (p < 0.0001). Predictors of transfusion were history of oral anticoagulant use, anterior circulation aneurysm, neurosurgical clipping, and lower Hb. Controlling for numerous potential confounders, transfusion was not independently associated with poor outcome.

Conclusions

We observed that moderate anemia remains very common early in admission following SAH. Only one-fifth of patients with SAH received RBC transfusions, mostly in cases of significant anemia (Hb < 80 g/L), and this did not appear to be associated with outcome.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2089-7) contains supplementary material, which is available to authorized users.