Postoperative troponin surveillance to detect myocardial infarction: an observational cohort modelling study

BACKGROUND

Clinical presentation of postoperative myocardial infarction (POMI) is often silent. Several international guidelines recommend routine troponin surveillance in patients at risk. We compared how these different guidelines select patients for surveillance after noncardiac surgery with our established risk stratification model.

METHODS

We used outcome data from two prospective studies: Measurement of Exercise Tolerance before Surgery (METS) and Troponin Elevation After Major non-cardiac Surgery (TEAMS). We compared the major American, Canadian, and European guideline recommendations for troponin surveillance with our established risk stratification model. For each guideline and model, we quantified the number of patients requiring monitoring, % POMI detected, sensitivity, specificity, diagnostic odds ratio, and number needed to screen (NNS).

RESULTS

METS and TEAMS contributed 2350 patients, of whom 319 (14%) had myocardial injury, 61 (2.5%) developed POMI, and 14 (0.6%) died. Our risk stratification model selected fewer patients for troponin monitoring (20%), compared with the Canadian (78%) and European (79%) guidelines. The sensitivity to detect POMI was highest with the Canadian and European guidelines (0.85; 95% confidence interval [CI] 0.74-0.92). Specificity was highest using the American guidelines (0.91; 95% CI 0.90-0.92). Our risk stratification model had the best diagnostic odds ratio (2.5; 95% CI 1.4-4.2) and a lower NNS (21 vs 35) compared with the guidelines.

CONCLUSIONS

Most postoperative myocardial infarctions were detected by the Canadian and European guidelines but at the cost of low specificity and a higher number of patients undergoing screening. Patient selection based on our risk stratification model was optimal.

Use of selective gut decontamination in critically ill children: PICnIC a pilot RCT and mixed-methods study

Background

Healthcare-associated infections are a major cause of morbidity and mortality in critically ill children. In adults, data suggest the use of selective decontamination of the digestive tract may reduce the incidence of healthcare-associated infections. Selective decontamination of the digestive tract has not been evaluated in the paediatric intensive care unit population.

Objectives

To determine the feasibility of conducting a multicentre, cluster-randomised controlled trial in critically ill children comparing selective decontamination of the digestive tract with standard infection control.

Design

Parallel-group pilot cluster-randomised controlled trial with an integrated mixed-methods study.

Setting

Six paediatric intensive care units in England.

Participants

Children (> 37 weeks corrected gestational age, up to 16 years) requiring mechanical ventilation expected to last for at least 48 hours were eligible for the PICnIC pilot cluster-randomised controlled trial. During the ecology periods, all children admitted to the paediatric intensive care units were eligible. Parents/legal guardians of recruited patients and healthcare professionals working in paediatric intensive care units were eligible for inclusion in the mixed-methods study.

Interventions

The interventions in the PICnIC pilot cluster-randomised controlled trial included administration of selective decontamination of the digestive tract as oro-pharyngeal paste and as a suspension given by enteric tube during the period of mechanical ventilation.

Main outcome measures

The decision as to whether a definitive cluster-randomised controlled trial is feasible is based on multiple outcomes, including (but not limited to): (1) willingness and ability to recruit eligible patients; (2) adherence to the selective decontamination of the digestive tract intervention; (3) acceptability of the definitive cluster-randomised controlled trial; (4) estimation of recruitment rate; and (5) understanding of potential clinical and ecological outcome measures.

Results

A total of 368 children (85% of all those who were eligible) were enrolled in the PICnIC pilot cluster-randomised controlled trial across six paediatric intensive care units: 207 in the baseline phase (Period One) and 161 in the intervention period (Period Two). In sites delivering selective decontamination of the digestive tract, the majority (98%) of children received at least one dose of selective decontamination of the digestive tract, and of these, 68% commenced within the first 6 hours. Consent for the collection of additional swabs was low (44%), though data completeness for potential outcomes, including microbiology data from routine clinical swab testing, was excellent. Recruited children were representative of the wider paediatric intensive care unit population. Overall, 3.6 children/site/week were recruited compared with the potential recruitment rate for a definitive cluster-randomised controlled trial of 3 children/site/week, based on data from all UK paediatric intensive care units. The proposed trial, including consent and selective decontamination of the digestive tract, was acceptable to parents and staff with adaptations, including training to improve consent and communication, and adaptations to the administration protocol for the paste and ecology monitoring. Clinical outcomes that were considered important included duration of organ failure and hospital stay, healthcare-acquired infections and survival.

Limitations

The delivery of the pilot cluster-randomised controlled trial was disrupted by the COVID-19 pandemic, which led to slow set-up of sites, and a lack of face-to face training.

Conclusions

PICnIC's findings indicate that a definitive cluster-randomised controlled trial in selective decontamination of the digestive tract in paediatric intensive care units is feasible with the inclusion modifications, which would need to be included in a definitive cluster-randomised controlled trial to ensure that the efficiency of trial processes is maximised.

Future work

A definitive trial that incorporates the protocol adaptations and outcomes arising from this study is feasible and should be conducted.

Trial registration

This trial is registered as ISRCTN40310490.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 16/152/01) and is published in full in Health Technology Assessment; Vol. 28, No. 8. See the NIHR Funding and Awards website for further award information.

Inhaled Volatiles for Status Asthmaticus, Epilepsy, and Difficult Sedation in Adult ICU and PICU: A Systematic Review

OBJECTIVES

Inhaled volatile anesthetics support management of status asthmaticus (SA), status epilepticus (SE), and difficult sedation (DS). This study aimed to evaluate the effectiveness, safety, and feasibility of using inhaled anesthetics for SA, SE, and DS in adult ICU and PICU patients.

DATA SOURCES

MEDLINE, Cochrane Central Register of Controlled Trials, and Embase.

STUDY SELECTION

Primary literature search that reported the use of inhaled anesthetics in ventilated patients with SA, SE, and DS from 1970 to 2021.

DATA EXTRACTION

Study data points were extracted by two authors independently. Quality assessment was performed using the Joanna Briggs Institute appraisal tool for case studies/series, Newcastle criteria for cohort/case-control studies, and risk-of-bias framework for clinical trials.

DATA SYNTHESIS

Primary outcome was volatile efficacy in improving predefined clinical or physiologic endpoints. Secondary outcomes were adverse events and delivery logistics. From 4281 screened studies, the number of included studies/patients across diagnoses and patient groups were: SA (adult: 38/121, pediatric: 28/142), SE (adult: 18/37, pediatric: 5/10), and DS (adult: 21/355, pediatric: 10/90). Quality of evidence was low, consisting mainly of case reports and series. Clinical and physiologic improvement was seen within 1-2 hours of initiating volatiles, with variable efficacy across diagnoses and patient groups: SA (adult: 89-95%, pediatric: 80-97%), SE (adults: 54-100%, pediatric: 60-100%), and DS (adults: 60-90%, pediatric: 62-90%). Most common adverse events were cardiovascular, that is, hypotension and arrhythmias. Inhaled sedatives were commonly delivered using anesthesia machines for SA/SE and miniature vaporizers for DS. Few (10%) of studies reported required non-ICU personnel, and only 16% had ICU volatile delivery protocol.

CONCLUSIONS

Volatile anesthetics may provide effective treatment in patients with SA, SE, and DS scenarios but the quality of evidence is low. Higher-quality powered prospective studies of the efficacy and safety of using volatile anesthetics to manage SA, SE, and DS patients are required. Education regarding inhaled anesthetics and the protocolization of their use is needed.

Cystatin C or creatinine for pre-operative assessment of kidney function and risk of post-operative acute kidney injury: a secondary analysis of the METS cohort study

Background

Post-operative acute kidney injury (PO-AKI) is a common surgical complication consistently associated with subsequent morbidity and mortality. Prior kidney dysfunction is a major risk factor for PO-AKI, however it is unclear whether serum creatinine, the conventional kidney function marker, is optimal in this population. Serum cystatin C is a kidney function marker less affected by body composition and might provide better prognostic information in surgical patients.

Methods

This was a pre-defined, secondary analysis of a multi-centre prospective cohort study of pre-operative functional capacity. Participants were aged ≥40 years, undergoing non-cardiac surgery. We assessed the association of pre-operative estimated glomerular filtration rate (eGFR) calculated using both serum creatinine and serum cystatin C with PO-AKI within 3 days after surgery, defined by KDIGO creatinine changes. The adjusted analysis accounted for established AKI risk factors.

Results

A total of 1347 participants were included (median age 65 years, interquartile range 56-71), of whom 775 (58%) were male. A total of 82/1347 (6%) patients developed PO-AKI. These patients were older, had higher prevalence of cardiovascular disease and related medication, were more likely to have intra-abdominal procedures, had more intraoperative transfusion, and were more likely to be dead at 1 year after surgery 6/82 (7.3%) vs 33/1265 (2.7%) (P = .038). Pre-operative eGFR was lower in AKI than non-AKI patients using both creatinine and cystatin C. When both measurements were considered in a single age- and sex-adjusted model, eGFR-Cysc was strongly associated with PO-AKI, with increasing risk of AKI as eGFR-Cysc decreased below 90, while eGFR-Cr was no longer significantly associated.

Conclusions

Data from over 1000 prospectively recruited surgical patients confirms pre-operative kidney function as major risk factor for PO-AKI. Of the kidney function markers available, compared with creatinine, cystatin C had greater strength of association with PO-AKI and merits further assessment in pre-operative assessment of surgical risk.

Health-related quality of life trajectories in critical illness: Protocol for a Monte Carlo simulation study

BACKGROUND

Health-related quality of life (HRQoL) is a patient-centred outcome increasingly used as a secondary outcome in critical care research. It may cover several important dimensions of clinical status in intensive care unit (ICU) patients that arguably elude other more easily quantified outcomes such as mortality. Poor associations with harder outcomes, conflicting data on HRQoL in critically ill compared to the background population, and paradoxical effects on HRQoL and mortality complicate the current operationalisation in critical care trials. This protocol outlines a simulation study that will gauge if the areas under the HRQoL trajectories could be a viable alternative.

METHODS

We will gauge the behaviour of the proposed HRQoL operationalisation through Monte Carlo simulations, under clinical scenarios that reflect a broad critical care population eligible for inclusion in a large pragmatic trial. We will simulate 15,360 clinical scenarios based on a full factorial design with the following seven simulation parameters: number of patients per arm, relative mortality reduction in the interventional arm, acceleration of HRQoL improvement in the interventional arm, the relative improvement in final HRQoL in the interventional arm, dampening effect of mortality on HRQoL values at discharge from the ICU, proportion of so-called mortality benefiters in the interventional arm and mortality trajectory shape. For each clinical scenario, we will simulate 100,000 two-arm trials with 1:1 randomisation. HRQoL will be sampled fortnightly after ICU discharge. Outcomes will include HRQoL in survivors and all patients at the end of follow-up; mean areas under the HRQoL trajectories in both arms; and mean difference between areas under the HRQoL trajectories and single-sampled HRQoLs at the end of follow-up.

DISCUSSION

In the outlined simulation study, we aim to assess whether the area under the HRQoL trajectory curve could be a candidate for reconciling the seemingly paradoxical effects on improved mortality and reduced HRQoL while remaining sensitive to early or accelerated improvement in patient outcomes. The resultant insights will inform subsequent methodological work on prudent collection and statistical analysis of such data from real critically ill patients.

Selective digestive tract decontamination to prevent healthcare associated infections in critically ill children: the PICNIC multicentre randomised pilot clinical trial

Healthcare-associated infections (HCAIs) are a major cause of morbidity and mortality in critically ill children. Data from adult studies suggest Selective Decontamination of the Digestive tract (SDD) may reduce the incidence of HCAIs and improve survival. There are no data from randomised clinical trials in the paediatric setting. An open label, parallel group pilot cRCT and mixed-methods perspectives study was conducted in six paediatric intensive care units (PICUs) in England. Participants were children (> 37 weeks corrected gestational age, up to 16 years) requiring mechanical ventilation expected to last for at least 48 h. Sites undertook standard care for a period of 9 weeks and were randomised into 3 sites which continued standard care and 3 where SDD was incorporated into infection control practice for eligible children. Interviews and focus groups were conducted for parents and staff working in PICU. 434 children fulfilled eligibility criteria, of whom 368 (85%) were enrolled. This included 207 in the baseline phase (Period One) and 161 in the intervention period (Period Two). In sites delivering SDD, the majority (98%) of children received at least one dose of SDD and of these, 68% commenced within the first 6 h. Whilst admission swabs were collected in 91% of enrolled children, consent for the collection of additional swabs was low (44%). Recruited children were representative of the wider PICU population. Overall, 3.6 children/site/week were recruited compared with the potential recruitment rate for a definitive cRCT of 3 children/site/week, based on data from all UK PICUs. Parents (n = 65) and staff (n = 44) were supportive of the aims of the study, suggesting adaptations for a larger definitive trial including formulation and administration of SDD paste, approaches to consent and ecology monitoring. Stakeholders identified preferred clinical outcomes, focusing on complications of critical illness and quality-of-life. A definitive cRCT in SDD to prevent HCAIs in critically ill children is feasible but should include adaptations to ecology monitoring along with the dosing schedule and packaging into a paediatric specific format. A definitive study is supported by the findings with adaptations to ecology monitoring and SDD administration.Trial Registration: ISRCTN40310490 Registered 30/10/2020.

Sex-related differences in functional capacity and its implications in risk stratification before major non-cardiac surgery: a post hoc analysis of the international METS study

Background

Poor functional capacity has been identified as an important modifiable risk factor for postoperative complications. Cardiopulmonary exercise testing (CPET) provides objective parameters of functional capacity (e.g., oxygen consumption at peak exercise, peak VO2), with significant prognostication for postoperative complications. However, sex-specific thresholds for functional capacity to predict surgical risk are yet to be established. Therefore, we performed a post hoc analysis of the international, multicentre, prospective observational METS (Measurement of Exercise Tolerance before Surgery) study to evaluate if sex-specific thresholds of peak VO2 improve risk prediction of postoperative complications.

Methods

We undertook a post hoc analysis (HREC/71824/PMCC) of the METS study, which was performed between March 2013 and March 2016. We investigated whether sex-specific differences exist for CPET-derived parameters and associated thresholds for predicting postoperative complications in this large cohort of patients that had major non-cardiac surgery (n = 1266). Logistic regression models were analyzed for the association of low peak VO2 with moderate-to-severe in-hospital postoperative complications. Optimal sex-specific peak VO2 thresholds were obtained by maximizing the Youden index of receiver operating characteristic (ROC) curves. Finally, multivariable logistic regression models tested the resulting sex-specific thresholds against the established non-sex-specific peak VO2 threshold (14 mL kg-1 min-1) adjusted for clinically relevant features such as comorbidities and surgical complexity. Models were evaluated by bootstrapping optimism-corrected area under the ROC curve and the net reclassification improvement index (NRI).

Findings

Female patients (n = 480) had a lower mean (SD) peak VO2 than males (16.7 (4.9) mL kg-1 min-1 versus 21.2 (6.5) mL kg-1 min-1, p < 0.001) and a lower postoperative complication rate (10.4% versus 15.3%; p = 0.018) than males (n = 786). The optimal peak VO2 threshold for predicting postoperative complications was 12.4 mL kg-1 min-1 for females and 22.3 mL kg-1 min-1 for males, respectively. In the multivariable regression model, low non-sex-specific peak VO2 did not independently predict postoperative complications. In contrast, low sex-specific peak VO2 was an independent predictor of postoperative complications (OR 2.29; 95% CI: 1.60, 3.30; p < 0.001). The optimism-corrected AUC-ROC of the sex-specific model was higher compared with the non-sex-specific model (0.73 versus 0.7; DeLong's test: p = 0.021). The sex-specific model classified 39% of the patients more correctly than the baseline model (NRI = 0.39; 95% CI: 0.24, 0.55). In contrast, the non-sex-specific model only classified 9% of the patients more correctly when compared against the baseline model (NRI = 0.09; 95% CI: -0.04, 0.22).

Interpretation

Our data report sex-specific differences in preoperative CPET-derived functional capacity parameters. Sex-specific peak VO2 thresholds identify patients at increased risk for postoperative complications with a higher discriminatory ability than a sex-unspecific threshold. As such, sex-specific threshold values should be considered in preoperative CPET to potentially improve risk stratification and to guide surgical decision-making, including eligibility for surgery, preoperative optimization strategies (prehabilitation) or seeking non-surgical options.

Funding

There was no funding for the present study. The original METS study was funded by Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Ontario Ministry of Health and Long-Term Care, Ontario Ministry of Research, Innovation and Science, UK National Institute of Academic Anaesthesia, UK Clinical Research Collaboration, Australian and New Zealand College of Anaesthetists, and Monash University.

Association between preoperative cardiac risk assessment and health care costs in major noncardiac surgery: a multicentre health economic analysis

PURPOSE

Patients with impaired functional capacity who undergo major surgery are at increased risk of postoperative morbidity including complications and increased length of stay. These outcomes have been associated with increased hospital and health system costs. We aimed to assess whether common preoperative risk indices are associated with postoperative cost.

METHODS

We conducted a health economic analysis focused on the subset of Measurement of Exercise Tolerance before Surgery (METS) study participants in Ontario, Canada. Participants were scheduled for major elective noncardiac surgery and underwent several preoperative assessments of cardiac risk, including physicians' subjective assessment, Duke Activity Status Index (DASI) questionnaire, peak oxygen consumption, and N-terminal pro-B-type natriuretic peptide concentration. Using linked health administrative data, postoperative costs were calculated for both one year and in-hospital. Using multiple regression models, we tested for association between the preoperative measures of cardiac risk and postoperative costs.

RESULTS

Our study included 487 patients (mean [standard deviation] age 68 [11] yr and 47.0% female) who underwent noncardiac surgery between 13 June 2013 and 8 March 2016. Overall, the median [interquartile range] cost incurred within one year postoperatively was CAD 27,587 [13,902-32,590], of which CAD 12,928 [10,253-12,810] were incurred in-hospital and CAD 14,497 [10,917-15,017] were incurred by 30 days. None of the four preoperative measures of cardiac risk assessment were associated with costs incurred in hospital or at one year postoperatively. This lack of strong association persisted in sensitivity analyses considering type of surgical procedure, burden of preoperative cost, and when costs were categorized as quantiles.

CONCLUSION

In patients undergoing major noncardiac surgery, common measures of functional capacity are not consistently associated with total postoperative cost. Until further data exist that differ from this analysis, clinicians and health care funders should not assume that preoperative measures of cardiac risk are associated with annual health care or hospital costs for such surgeries.

Effect of inhaled anaesthetics on cognitive and psychiatric outcomes in critically ill adults: a systematic review and meta-analysis

BACKGROUND

Sedation of critically ill patients with inhaled anaesthetics may reduce lung inflammation, time to extubation, and ICU length of stay compared with intravenous (i.v.) sedatives. However, the impact of inhaled anaesthetics on cognitive and psychiatric outcomes in this population is unclear. In this systematic review, we aimed to summarise the effect of inhaled anaesthetics on cognitive and psychiatric outcomes in critically ill adults.

METHODS

We searched MEDLINE, EMBASE, and PsycINFO for case series, retrospective, and prospective studies in critically ill adults sedated with inhaled anaesthetics. Outcomes included delirium, psychomotor and neurological recovery, long-term cognitive dysfunction, ICU memories, anxiety, depression, post-traumatic stress disorder (PTSD), and instruments used for assessment.

RESULTS

Thirteen studies were included in distinct populations of post-cardiac arrest survivors (n=4), postoperative noncardiac patients (n=3), postoperative cardiac patients (n=2), and mixed medical-surgical patients (n=4). Eight studies reported delirium incidence, two neurological recovery, and two ICU memories. One study reported on psychomotor recovery, long-term cognitive dysfunction, anxiety, depression, and PTSD. A meta-analysis of five trials found no difference in delirium incidence between inhaled and i.v. sedatives (relative risk 0.95 [95% confidence interval: 0.59-1.54]). Compared with i.v. sedatives, inhaled anaesthetics were associated with fewer hallucinations and faster psychomotor recovery but no differences in other outcomes. There was heterogeneity in the instruments used and timing of these assessments.

CONCLUSIONS

Based on the limited evidence available, there is no difference in cognitive and psychiatric outcomes between adults exposed to volatile sedation or intravenous sedation in the ICU. Future studies should incorporate outcome assessment with validated tools during and after hospital stay.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42021236455.

Tracheostomy timing and outcome in critically ill patients with stroke: a meta-analysis and meta-regression

BACKGROUND

Stroke patients requiring mechanical ventilation often have a poor prognosis. The optimal timing of tracheostomy and its impact on mortality in stroke patients remains uncertain. We performed a systematic review and meta-analysis of tracheostomy timing and its association with reported all-cause overall mortality. Secondary outcomes were the effect of tracheostomy timing on neurological outcome (modified Rankin Scale, mRS), hospital length of stay (LOS), and intensive care unit (ICU) LOS.

METHODS

We searched 5 databases for entries related to acute stroke and tracheostomy from inception to 25 November 2022. We adhered to PRISMA guidance for reporting systematic reviews and meta-analyses. Selected studies included (1) ICU-admitted patients who had stroke (either acute ischaemic stroke, AIS or intracerebral haemorrhage, ICH) and received a tracheostomy (with known timing) during their stay and (2) > 20 tracheotomised. Studies primarily reporting sub-arachnoid haemorrhage (SAH) were excluded. Where this was not possible, adjusted meta-analysis and meta-regression with study-level moderators were performed. Tracheostomy timing was analysed continuously and categorically, where early (< 5 days from initiation of mechanical ventilation to tracheostomy) and late (> 10 days) timing was defined per the protocol of SETPOINT2, the largest and most recent randomised controlled trial on tracheostomy timing in stroke patients.

RESULTS

Thirteen studies involving 17,346 patients (mean age = 59.8 years, female 44%) met the inclusion criteria. ICH, AIS, and SAH comprised 83%, 12%, and 5% of known strokes, respectively. The mean time to tracheostomy was 9.7 days. Overall reported all-cause mortality (adjusted for follow-up) was 15.7%. One in five patients had good neurological outcome (mRS 0-3; median follow-up duration was 180 days). Overall, patients were ventilated for approximately 12 days and had an ICU LOS of 16 days and a hospital LOS of 28 days. A meta-regression analysis using tracheostomy time as a continuous variable showed no statistically significant association between tracheostomy timing and mortality (β = - 0.3, 95% CI = - 2.3 to 1.74, p = 0.8). Early tracheostomy conferred no mortality benefit when compared to late tracheostomy (7.8% vs. 16.4%, p = 0.7). Tracheostomy timing was not associated with secondary outcomes (good neurological outcome, ICU LOS and hospital LOS).

CONCLUSIONS

In this meta-analysis of over 17,000 critically ill stroke patients, the timing of tracheostomy was not associated with mortality, neurological outcomes, or ICU/hospital LOS.

TRIAL REGISTRATION

PROSPERO-CRD42022351732 registered on 17th of August 2022.

Co-designed and consensus based development of a quality improvement checklist of patient and family-centered actionable processes of care for adults with persistent critical illness

PURPOSE

Few quality improvement tools specific to patients with persistent or chronic critical illness exist to aid delivery of high-quality care. Using experience-based co-design methods, we sought consensus from key stakeholders on the most important actionable processes of care for inclusion in a quality improvement checklist.

METHODS

Item generation methods: systematic review, semi-structured interviews (ICU survivors and family) members, touchpoint video creation, and semi-structured interviews (ICU clinicians). Consensus methods: modified online Delphi and a virtual meeting using nominal group technique methods.

RESULTS

We enrolled 138 ICU interprofessional team, patients, and family members. We obtained consensus on a quality improvement checklist comprising 11 core domains: patient and family involvement in decision-making; patient communication; physical comfort and complication prevention; promoting self-care and normalcy; ventilator weaning; physical therapy; swallowing; pharmacotherapy; psychological issues; delirium; and appropriate referrals. An additional 27 actionable processes are contained within 6 core domains that provide more specific direction on the actionable process to be targeted.

CONCLUSIONS

Using a highly collaborative and methodologically rigorous process, we generated a quality improvement checklist of actionable processes to improve patient and family-centred care considered important by key stakeholders. Future research is needed to understand optimal implementation strategies and impact on outcomes and experience.

Effect of Selective Decontamination of the Digestive Tract on Hospital Mortality in Critically Ill Patients Receiving Mechanical Ventilation: A Randomized Clinical Trial

IMPORTANCE

Whether selective decontamination of the digestive tract (SDD) reduces mortality in critically ill patients remains uncertain.

OBJECTIVE

To determine whether SDD reduces in-hospital mortality in critically ill adults.

DESIGN, SETTING, AND PARTICIPANTS

A cluster, crossover, randomized clinical trial that recruited 5982 mechanically ventilated adults from 19 intensive care units (ICUs) in Australia between April 2018 and May 2021 (final follow-up, August 2021). A contemporaneous ecological assessment recruited 8599 patients from participating ICUs between May 2017 and August 2021.

INTERVENTIONS

ICUs were randomly assigned to adopt or not adopt a SDD strategy for 2 alternating 12-month periods, separated by a 3-month interperiod gap. Patients in the SDD group (n = 2791) received a 6-hourly application of an oral paste and administration of a gastric suspension containing colistin, tobramycin, and nystatin for the duration of mechanical ventilation, plus a 4-day course of an intravenous antibiotic with a suitable antimicrobial spectrum. Patients in the control group (n = 3191) received standard care.

MAIN OUTCOMES AND MEASURES

The primary outcome was in-hospital mortality within 90 days. There were 8 secondary outcomes, including the proportion of patients with new positive blood cultures, antibiotic-resistant organisms (AROs), and Clostridioides difficile infections. For the ecological assessment, a noninferiority margin of 2% was prespecified for 3 outcomes including new cultures of AROs.

RESULTS

Of 5982 patients (mean age, 58.3 years; 36.8% women) enrolled from 19 ICUs, all patients completed the trial. There were 753/2791 (27.0%) and 928/3191 (29.1%) in-hospital deaths in the SDD and standard care groups, respectively (mean difference, -1.7% [95% CI, -4.8% to 1.3%]; odds ratio, 0.91 [95% CI, 0.82-1.02]; P = .12). Of 8 prespecified secondary outcomes, 6 showed no significant differences. In the SDD vs standard care groups, 23.1% vs 34.6% had new ARO cultures (absolute difference, -11.0%; 95% CI, -14.7% to -7.3%), 5.6% vs 8.1% had new positive blood cultures (absolute difference, -1.95%; 95% CI, -3.5% to -0.4%), and 0.5% vs 0.9% had new C difficile infections (absolute difference, -0.24%; 95% CI, -0.6% to 0.1%). In 8599 patients enrolled in the ecological assessment, use of SDD was not shown to be noninferior with regard to the change in the proportion of patients who developed new AROs (-3.3% vs -1.59%; mean difference, -1.71% [1-sided 97.5% CI, -∞ to 4.31%] and 0.88% vs 0.55%; mean difference, -0.32% [1-sided 97.5% CI, -∞ to 5.47%]) in the first and second periods, respectively.

CONCLUSIONS AND RELEVANCE

Among critically ill patients receiving mechanical ventilation, SDD, compared with standard care without SDD, did not significantly reduce in-hospital mortality. However, the confidence interval around the effect estimate includes a clinically important benefit.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02389036.

Measurement properties of the WHO Disability Assessment Schedule 2.0 for evaluating functional status after inpatient surgery

BACKGROUND

Expert recommendations propose the WHO Disability Assessment Schedule (WHODAS) 2.0 as a core outcome measure in surgical studies, yet data on its long-term measurement properties remain limited. These were evaluated in a secondary analysis of the Measurement of Exercise Tolerance before Surgery (METS) prospective cohort.

METHODS

Participants were adults (40 years of age or older) who underwent inpatient non-cardiac surgery. The 12-item WHODAS and EQ-5DTM-3L questionnaires were administered preoperatively (in person) and 1 year postoperatively (by telephone). Responsiveness was characterized using standardized response means (SRMs) and correlation coefficients between change scores. Construct validity was evaluated using correlation coefficients between 1-year scores and comparisons of WHODAS scores across clinically relevant subgroups.

RESULTS

The analysis included 546 patients. There was moderate correlation between changes in WHODAS and various EQ-5DTM subscales. The strongest correlation was between changes in WHODAS and changes in the functional domains of the EQ-5D-3L-for example, mobility (Spearman's rho 0.40, 95 per cent confidence interval [c.i.] 0.32 to 0.48) and usual activities (rho 0.45, 95 per cent c.i. 0.30 to 0.52). When compared across quartiles of EQ-5D index change, median WHODAS scores followed expected patterns of change. In subgroups with expected functional status changes, the WHODAS SRMs ranged from 'small' to 'large' in the expected directions of change. At 1 year, the WHODAS demonstrated convergence with the EQ-5D-3L functional domains, and good discrimination between patients with expected differences in functional status.

CONCLUSION

The WHODAS questionnaire has construct validity and responsiveness as a measure of functional status at 1 year after major surgery.

Effect of oral chlorhexidine de-adoption and implementation of an oral care bundle on mortality for mechanically ventilated patients in the intensive care unit (CHORAL): a multi-center stepped wedge cluster-randomized controlled trial

Purpose

Oral chlorhexidine is used widely for mechanically ventilated patients to prevent pneumonia, but recent studies show an association with excess mortality. We examined whether de-adoption of chlorhexidine and parallel implementation of a standardized oral care bundle reduces intensive care unit (ICU) mortality in mechanically ventilated patients.

Methods

A stepped wedge cluster-randomized controlled trial with concurrent process evaluation in 6 ICUs in Toronto, Canada. Clusters were randomized to de-adopt chlorhexidine and implement a standardized oral care bundle at 2-month intervals. The primary outcome was ICU mortality. Secondary outcomes were time to infection-related ventilator-associated complications (IVACs), oral procedural pain and oral health dysfunction. An exploratory post hoc analysis examined time to extubation in survivors.

Results

A total of 3260 patients were enrolled; 1560 control, 1700 intervention. ICU mortality for the intervention and control periods were 399 (23.5%) and 330 (21.2%), respectively (adjusted odds ratio [aOR], 1.13; 95% confidence interval [CI] 0.82 to 1.54; P = 0.46). Time to IVACs (adjusted hazard ratio [aHR], 1.06; 95% CI 0.44 to 2.57; P = 0.90), time to extubation (aHR 1.03; 95% CI 0.85 to 1.23; P = 0.79) (survivors) and oral procedural pain (aOR, 0.62; 95% CI 0.34 to 1.10; P = 0.10) were similar between control and intervention periods. However, oral health dysfunction scores (− 0.96; 95% CI − 1.75 to − 0.17; P = 0.02) improved in the intervention period.

Conclusion

Among mechanically ventilated ICU patients, no benefit was observed for de-adoption of chlorhexidine and implementation of an oral care bundle on ICU mortality, IVACs, oral procedural pain, or time to extubation. The intervention may improve oral health.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00134-021-06475-2.

Placebo comparator group selection and use in surgical trials: the ASPIRE project including expert workshop

BACKGROUND

The use of placebo comparisons for randomised trials assessing the efficacy of surgical interventions is increasingly being considered. However, a placebo control is a complex type of comparison group in the surgical setting and, although powerful, presents many challenges.

OBJECTIVES

To provide a summary of knowledge on placebo controls in surgical trials and to summarise any recommendations for designers, evaluators and funders of placebo-controlled surgical trials.

DESIGN

To carry out a state-of-the-art workshop and produce a corresponding report involving key stakeholders throughout.

SETTING

A workshop to discuss and summarise the existing knowledge and to develop the new guidelines.

RESULTS

To assess what a placebo control entails and to assess the understanding of this tool in the context of surgery is considered, along with when placebo controls in surgery are acceptable (and when they are desirable). We have considered ethics arguments and regulatory requirements, how a placebo control should be designed, how to identify and mitigate risk for participants in these trials, and how such trials should be carried out and interpreted. The use of placebo controls is justified in randomised controlled trials of surgical interventions provided that there is a strong scientific and ethics rationale. Surgical placebos might be most appropriate when there is poor evidence for the efficacy of the procedure and a justified concern that results of a trial would be associated with a high risk of bias, particularly because of the placebo effect.

CONCLUSIONS

The use of placebo controls is justified in randomised controlled trials of surgical interventions provided that there is a strong scientific and ethics rationale. Feasibility work is recommended to optimise the design and implementation of randomised controlled trials. An outline for best practice was produced in the form of the Applying Surgical Placebo in Randomised Evaluations (ASPIRE) guidelines for those considering the use of a placebo control in a surgical randomised controlled trial.

LIMITATIONS

Although the workshop participants involved international members, the majority of participants were from the UK. Therefore, although every attempt was made to make the recommendations applicable to all health systems, the guidelines may, unconsciously, be particularly applicable to clinical practice in the UK NHS.

FUTURE WORK

Future work should evaluate the use of the ASPIRE guidelines in making decisions about the use of a placebo-controlled surgical trial. In addition, further work is required on the appropriate nomenclature to adopt in this space.

FUNDING

Funded by the Medical Research Council UK and the National Institute for Health Research as part of the Medical Research Council-National Institute for Health Research Methodology Research programme.

Functional decline after major elective non-cardiac surgery: a multicentre prospective cohort study

Self-reported postoperative functional recovery is an important patient-centred outcome that is rarely measured or considered in research and decision-making. We conducted a secondary analysis of the measurement of exercise tolerance before surgery (METS) study for associations of peri-operative variables with functional decline after major non-cardiac surgery. Patients who were at least 40 years old, had or were at risk of, coronary artery disease and who were scheduled for non-cardiac surgery were recruited. Primary outcome was a reduction in mobility, self-care or ability to conduct usual activities (EuroQol 5 dimension) from before surgery to 30 days and 1 year after surgery. A decline in at least one function was reported by 523/1309 (40%) participants at 30 days and 320/1309 (24%) participants at 1 year. Participants who reported higher pre-operative Duke Activity Status indices more often reported functional decline 30 days after surgery and less often reported functional decline 1 year after surgery. The odds ratios (95%CI) of functional decline 30 days and 1 year after surgery with moderate or severe postoperative complications were 1.46 (1.02-2.09), p = 0.037 and 1.44 (0.98-2.13), p = 0.066. Discrimination of participants who reported functional decline 30 days and 1 year after surgery were poor (c-statistic 0.61 and 0.63, respectively). In summary, one quarter of participants reported functional decline up to one postoperative year.

Barriers and Facilitators to Early Rehabilitation in the ICU: A Theory Driven Delphi Study

OBJECTIVES

There is conflicting evidence for the effectiveness of early rehabilitation in the intensive care and marked variation in rates of implementation in practice. We aimed to identify barriers and facilitators to early rehabilitation in mechanically ventilated patients and their relevance to practice, as perceived by key ICU clinicians across North America.

DESIGN

A Delphi study using the Theoretical Domains Framework, consisting of an initial qualitative round and subsequent quantitative rounds, was conducted to gather clinician agreement and perceived importance of barriers and facilitators to early rehabilitation. The survey included questions on the range of individual, sociocultural, and broader organizational influence on behaviors.

SETTING

Clinical practice in North America.

SUBJECTS

Four clinician groups (intensive care physicians, nurses, therapists, and respiratory therapists).

INTERVENTIONS

A three-round Delphi study.

MEASUREMENTS AND MAIN RESULTS

Fifty of 74 (67%) of invited clinicians completed the study. Agreement and consensus with Delphi survey items were high in both rounds within and between professional groups. Agreement was highest for items related to the domain "Beliefs about Consequences" (e.g., mortality reduction) and lowest for items related to the domain "Behavioral Regulation" (e.g., team discussion of barriers). Beliefs expressed about improved mortality and improvements in a variety of other long-term outcomes were not consistent with the current evidence base. Individual agreement scores changed very little from Round 2 to Round 3 of the Delphi, suggesting stability of beliefs and existing consensus.

CONCLUSIONS

This study identified a wide range of beliefs about early rehabilitation that may influence provider behavior and the success and appropriateness of further implementation. The apparent inconsistency between the optimism of stakeholders regarding mortality reductions and a low level of implementation reported elsewhere represent the most major challenge to future implementation success. Other foci for future implementation work include planning, barriers, feedback, and education of staff.

Acute healthcare resource utilization by age: A cohort study

Background

Granular data related to the likelihood of individuals of different ages accessing acute and critical care services over time is lacking.

Methods

We used population-based, administrative data from Ontario to identify residents of specific ages (20, 30, 40, etc. to 100) on January 1^st every year from 1995–2019. We assessed rates of emergency department (ED) visits (2003–19), hospitalizations, intensive care unit (ICU) admissions (2003–19), and mechanical ventilation.

Findings

Overall the 25-year study period, ED were the most common acute healthcare encounter with 100-year-olds having the lowest rate (138.7/1,000) and 90-year-olds the highest (378.5/1,000). Rates of hospitalization ranged from 24.2/1,000 for those age 20 up to 224.9/1,000 for those age 90. Rates of ICU admission and mechanical ventilation were lowest for those age 20 (1.0 and 0.4/1,000), more than tripled by age 50 (3.3 and 1.7/1,000) and peaked at age 80 (20.3 and 10.1/1,000). Over time rates of ED visits increased (164.3 /1,000 in 2003 vs 199.1 /1,000 in 2019) as did rates of invasive mechanical ventilation (2.0/1,000 in 1995 vs 2.9/1,000 in 2019), whereas rates of ICU admission remained stable (4.8/1,000 in 2003 vs 4.9/1,000 in 2019) and hospitalization declined (66.8/1,000 in 1995 vs 51.5/1,000 in 2019). Age stratified analysis demonstrated that rates of ED presentation increased for those age 70 and younger while hospitalization decreased for all age groups; ICU admission and mechanical ventilation rates changed variably by age, with increasing rates demonstrated primarily among people under the age of 50.

Interpretation

Rates of hospitalizations have decreased over time across all age groups, whereas rates of ED presentation, ICU admissions, and mechanical ventilation have increased, primarily driven by younger adults. These findings suggest that although the delivery of healthcare may be moving away from inpatient medicine, there is a growing population of young adults requiring significant healthcare resources.

Association of six-minute walk test distance with postoperative complications in non-cardiac surgery: a secondary analysis of a multicentre prospective cohort study

PURPOSE

The six-minute walk test (6MWT) is a simple and valid test for assessing cardiopulmonary fitness. Nevertheless, the relationship between preoperative 6MWT distance and postoperative complications is uncertain. We conducted a secondary analysis of the 6MWT nested cohort substudy of the Measurement of Exercise Tolerance before Surgery study to determine if 6MWT distance predicts postoperative complications or death.

METHODS

This analysis included 545 adults (≥ 40 yr) who were at elevated cardiac risk and had elective inpatient non-cardiac surgery at 15 hospitals in Canada, Australia, and New Zealand. Each participant performed a preoperative 6MWT and was followed for 30 days after surgery. The primary outcome was moderate or severe in-hospital complications. The secondary outcome was 30-day death or myocardial injury. Multivariable logistic regression modelling was used to characterize the adjusted association of 6MWT distance with these outcomes.

RESULTS

Seven participants (1%) terminated their 6MWT sessions early because of lower limb pain, dyspnea, or dizziness. Eighty-one (15%) participants experienced moderate or severe complications and 69 (13%) experienced 30-day myocardial injury or death. Decreased 6MWT distance was associated with increased odds of moderate or severe complications (adjusted odds ratio, 1.32 per 100 m decrease; 95% confidence interval, 1.01 to 1.73; P = 0.045). There was no association of 6MWT distance with myocardial injury or 30-day death (non-linear association; P = 0.49).

CONCLUSION

Preoperative 6MWT distance had a modest association with moderate or severe complications after inpatient non-cardiac surgery. Further studies are needed to determine the optimal role of the 6MWT as an objective exercise test for informing preoperative risk stratification.

A Pragmatic Non-Randomized Trial of Prehabilitation Prior to Cancer Surgery: Study Protocol and COVID-19-Related Adaptations

Background

Experimental data highlight the potential benefits and health system cost savings related to surgical prehabilitation; however, adequately powered randomized controlled trial (RCT) data remain nascent. Emerging prehabilitation services may be informed by early RCT data but can be limited in informing real-world program development. Pragmatic trials emphasize external validity and generalizability to understand and advise intervention development and implementation in clinical settings. This paper presents the methodology of a pragmatic prehabilitation trial to complement emerging phase III clinical trials and inform implementation strategies.

Methods

This is a pilot pragmatic clinical trial conducted in a large academic hospital in Toronto, Ontario, Canada to assess feasibility of clinical implementation and derive estimates of effectiveness. Feasibility data include program referral rates, enrolment and attrition, intervention adherence and safety, participant satisfaction, and barriers and facilitators to programming. The study aims to receive 150 eligible referrals for adult, English-speaking, preoperative oncology patients with an identified indication for prehabilitation (e.g., frailty, deconditioning, malnutrition, psychological distress). Study participants undergo a baseline assessment and shared-decision making regarding the intervention setting: either facility-based prehabilitation or home-based prehabilitation. In both scenarios, participants receive an individualized exercise prescription, stress-reduction psychological support, nutrition counseling, and protein supplementation, and if appropriate, smoking cessation program referrals. Secondary objectives include estimating intervention effects at the week prior to surgery and 30 and 90 days postoperatively. Outcomes include surgical complications, postoperative length of stay, mortality, hospital readmissions, physical fitness, psychological well-being, and quality of life. Data from participants who decline the intervention but consent for research-related access to health records will serve as comparators. The COVID-19 pandemic required the introduction of a 'virtual program' using only telephone or internet-based communication for screening, assessments, or intervention was introduced.

Conclusion

This pragmatic trial will provide evidence on the feasibility and viability of prehabilitation services delivered under usual clinical conditions. Study amendments due to the COVID-19 pandemic are presented as strategies to maintain prehabilitation research and services to potentially mitigate the consequences of extended surgery wait times.

Comparison of 2 Triage Scoring Guidelines for Allocation of Mechanical Ventilators

IMPORTANCE

In the current setting of the coronavirus disease 2019 pandemic, there is concern for the possible need for triage criteria for ventilator allocation; to our knowledge, the implications of using specific criteria have never been assessed.

OBJECTIVE

To determine which and how many admissions to intensive care units are identified as having the lowest priority for ventilator allocation using 2 distinct sets of proposed triage criteria.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study conducted in spring 2020 used data collected from US hospitals and reported in the Philips eICU Collaborative Research Database. Adult admissions (N = 40 439) to 291 intensive care units from 2014 to 2015 who received mechanical ventilation and were not elective surgery patients were included.

EXPOSURES

New York State triage criteria and original triage criteria proposed by White and Lo.

MAIN OUTCOMES AND MEASURES

Sequential Organ Failure Assessment (SOFA) scores were calculated for admissions. The proportion of patients who met initial criteria for the lowest level of priority for mechanical ventilation using each set of criteria and their characteristics and outcomes were assessed. Agreement was compared between the 2 sets of triage criteria, recognizing differences in stated criteria aims.

RESULTS

Among 40 439 intensive care unit admissions of patients who received mechanical ventilation, the mean (SD) age was 62.6 (16.6) years, 54.9% were male, and the mean (SD) SOFA score was 4.5 (3.7). Using the New York State triage criteria, 8.9% (95% CI, 8.7%-9.2%) were in the lowest priority category; these lowest priority admissions had a mean (SD) age of 62.9 (16.6) years, used a median (interquartile range) of 57.3 (20.1-133.5) ventilator hours each, and had a hospital survival rate of 38.6% (95% CI, 37.0%-40.2%). Using the White and Lo triage criteria, 4.3% (95% CI, 4.1%-4.5%) were in the lowest priority category; these admissions had a mean (SD) age of 68.6 (13.2) years, used a median (interquartile range) of 61.7 (24.3-142.8) ventilator hours each, and had a hospital survival rate of 56.2% (95% CI, 53.8%-58.7%). Only 655 admissions (1.6%) were in the lowest priority category for both guidelines, with the κ statistic for agreement equal to 0.20 (95% CI, 0.18-0.21).

CONCLUSIONS AND RELEVANCE

Use of 2 initially proposed ventilator triage guidelines identified approximately 1 in every 10 to 25 admissions as having the lowest priority for ventilator allocation, with little agreement. Clinical assessment of different potential criteria for triage decisions in critically ill populations is important to ensure valid and equitable allocation of resources.

MicroRNA signatures of perioperative myocardial injury after elective noncardiac surgery: a prospective observational mechanistic cohort study

BACKGROUND

Elevated plasma or serum troponin, indicating perioperative myocardial injury (PMI), is common after noncardiac surgery. However, underlying mechanisms remain unclear. Acute coronary syndrome (ACS) is associated with the early appearance of circulating microRNAs, which regulate post-translational gene expression. We hypothesised that if PMI and ACS share pathophysiological mechanisms, common microRNA signatures should be evident.

METHODS

We performed a nested case control study of samples obtained before and after noncardiac surgery from patients enrolled in two prospective observational studies of PMI (postoperative troponin I/T>99th centile). In cohort one, serum microRNAs were compared between patients with or without PMI, matched for age, gender, and comorbidity. Real-time polymerase chain reaction quantified (qRT-PCR) relative microRNA expression (cycle quantification [Cq] threshold <37) before and after surgery for microRNA signatures associated with ACS, blinded to PMI. In cohort two, we analysed (EdgeR) microRNA from plasma extracellular vesicles using next-generation sequencing (Illumina HiSeq 500). microRNA-messenger RNA-function pathway analysis was performed (DIANA miRPath v3.0/TopGO).

RESULTS

MicroRNAs were detectable in all 59 patients (median age 67 yr [61-75]; 42% male), who had similar clinical characteristics independent of developing PMI. In cohort one, serum microRNA expression increased after surgery (mean fold-change) hsa-miR-1-3p: 3.99 (95% confidence interval [CI: 1.95-8.19]; hsa-miR-133-3p: 5.67 [95% CI: 2.94-10.91]; P<0.001). These changes were not associated with PMI. Bioinformatic analysis of differentially expressed microRNAs from cohorts one (n=48) and two (n=11) identified pathways associated with adrenergic stress and calcium dysregulation, rather than ischaemia.

CONCLUSIONS

Circulating microRNAs associated with cardiac ischaemia were universally elevated in patients after surgery, independent of development of myocardial injury.

Considerations and methods for placebo controls in surgical trials (ASPIRE guidelines)

Placebo comparisons are increasingly being considered for randomised trials assessing the efficacy of surgical interventions. The aim of this Review is to provide a summary of knowledge on placebo controls in surgical trials. A placebo control is a complex type of comparison group in the surgical setting and, although powerful, presents many challenges. This Review outlines what a placebo control entails and present understanding of this tool in the context of surgery. We consider when placebo controls in surgery are acceptable (and when they are desirable) in terms of ethical arguments and regulatory requirements, how a placebo control should be designed, how to identify and mitigate risk for participants in these trials, and how such trials should be done and interpreted. Use of placebo controls is justified in randomised controlled trials of surgical interventions provided there is a strong scientific and ethical rationale. Surgical placebos might be most appropriate when there is poor evidence for the efficacy of the procedure and a justified concern that results of a trial would be associated with high risk of bias, particularly because of the placebo effect. Feasibility work is recommended to optimise the design and implementation of randomised controlled trials. This Review forms an outline for best practice and provides guidance, in the form of the Applying Surgical Placebo in Randomised Evaluations (known as ASPIRE) checklist, for those considering the use of a placebo control in a surgical randomised controlled trial.

Selective decontamination of the digestive tract (SDD) in critically ill patients: a narrative review

Selective decontamination of the digestive tract (SDD) is an infection prevention measure for intensive care unit (ICU) patients that was proposed more than 30 years ago, and that is currently considered standard of care in the Netherlands, but only used sporadically in ICUs in other countries. In this narrative review, we first describe the rationale of the individual components of SDD and then review the evidence base for patient-centered outcomes, where we distinguish ICUs with low prevalence of antibiotic resistance from ICUs with moderate–high prevalence of resistance. In settings with low prevalence of antibiotic resistance, SDD has been associated with improved patient outcome in three cluster-randomized studies. These benefits were not confirmed in a large international cluster-randomized study in settings with moderate-to-high prevalence of antibiotic resistance. There is no evidence that SDD increases antibiotic resistance. We end with future directions for research.

Protocol for a multi-centered, stepped wedge, cluster randomized controlled trial of the de-adoption of oral chlorhexidine prophylaxis and implementation of an oral care bundle for mechanically ventilated critically ill patients: the CHORAL study

BACKGROUND

Routine application of chlorhexidine oral rinse is recommended to reduce risk of ventilator-associated pneumonia (VAP) in mechanically ventilated patients. Recent reappraisal of the evidence from two meta-analyses suggests chlorhexidine may cause excess mortality in non-cardiac surgery patients and does not reduce VAP. Mechanisms for possible excess mortality are unclear. The CHORAL study will evaluate the impact of de-adopting chlorhexidine and implementing an oral care bundle (excluding chlorhexidine) on mortality, infection-related ventilator-associated complications (IVACs), and oral health status.

METHODS

The CHORAL study is a stepped wedge, cluster randomized controlled trial in six academic intensive care units (ICUs) in Toronto, Canada. Clusters (ICU) will be randomly allocated to six sequential steps over a 14-month period to de-adopt oral chlorhexidine and implement a standardized oral care bundle (oral assessment, tooth brushing, moisturization, and secretion removal). On study commencement, all clusters begin with a control period in which the standard of care is oral chlorhexidine. Clusters then begin crossover from control to intervention every 2 months according to the randomization schedule. Participants include all mechanically ventilated adults eligible to receive the standardized oral care bundle. The primary outcome is ICU mortality; secondary outcomes are IVACs and oral health status. We will determine demographics, antibiotic usage, mortality, and IVAC rates from a validated local ICU clinical registry. With six clusters and 50 ventilated patients on average each month per cluster, we estimate that 4200 patients provide 80% power after accounting for intracluster correlation to detect an absolute reduction in mortality of 5.5%. We will analyze our primary outcome of mortality using a generalized linear mixed model adjusting for time to account for secular trends. We will conduct a process evaluation to determine intervention fidelity and to inform interpretation of the trial results.

DISCUSSION

The CHORAL study will inform understanding of the effectiveness of de-adoption of oral chlorhexidine and implementation of a standardized oral care bundle for decreasing ICU mortality and IVAC rates while improving oral health status. Our process evaluation will inform clinicians and decision makers about intervention delivery to support future de-adoption if justified by trial results.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03382730 . Registered on December 26, 2017.

Relative value of cystatin C and creatinine-based estimates of glomerular filtration rate in predicting long-term mortality after cardiac surgery: a cohort study

OBJECTIVE

Renal dysfunction predicts an increased risk of both early and long-term mortality after cardiac surgery. Cystatin C enables glomerular filtration rate (GFR) to be estimated accurately and may be superior in this regard to creatinine-based estimates. We hypothesised, therefore, that cystatin C and derived estimates of GFR would independently predict long-term survival after cardiac surgery and would be superior in this respect to traditional estimates of GFR. The current study tests this hypothesis in a large and well-characterised cohort of patients.

DESIGN

A prospective cohort study.

SETTING

Regional cardiothoracic centre in Northeast Scotland.

PARTICIPANTS

1010 patients undergoing non-emergent cardiac surgery between 2004 and 2007. Serum creatinine and cystatin C levels were measured preoperatively and demographic and clinical variables were recorded.

PRIMARY OUTCOME MEASURE

All-cause mortality, established from the National Records of Scotland.

RESULTS

The median duration of follow-up after surgery was 9.7 years (IQR 8.9-10.6 years), during which 297 participants died. Preoperative creatinine and cystatin C levels and estimates of GFR derived from these were all strong predictors of death using Cox regression and remained independently predictive after adjustment for the logistic European System for Cardiac Operative Risk Evaluation, a well-validated clinical risk score and a range of other clinical predictors. Cystatin C-based measures were superior to creatinine-based estimates of GFR.

CONCLUSIONS

Cystatin C and creatinine derived eGFR are powerful and independent predictors of long-term mortality following cardiac surgery. Estimates of GFR derived from cystatin C convey superior prognostic information to conventional creatinine-based estimates, but the observed differences are modest.

Heart rate recovery and morbidity after noncardiac surgery: Planned secondary analysis of two prospective, multi-centre, blinded observational studies

Background

Impaired cardiac vagal function, quantified preoperatively as slower heart rate recovery (HRR) after exercise, is independently associated with perioperative myocardial injury. Parasympathetic (vagal) dysfunction may also promote (extra-cardiac) multi-organ dysfunction, although perioperative data are lacking. Assuming that cardiac vagal activity, and therefore heart rate recovery response, is a marker of brainstem parasympathetic dysfunction, we hypothesized that impaired HRR would be associated with a higher incidence of morbidity after noncardiac surgery.

Methods

In two prospective, blinded, observational cohort studies, we established the definition of impaired vagal function in terms of the HRR threshold that is associated with perioperative myocardial injury (HRR ≤ 12 beats min^-1 (bpm), 60 seconds after cessation of cardiopulmonary exercise testing. The primary outcome of this secondary analysis was all-cause morbidity three and five days after surgery, defined using the Post-Operative Morbidity Survey. Secondary outcomes of this analysis were type of morbidity and time to become morbidity-free. Logistic regression and Cox regression tested for the association between HRR and morbidity. Results are presented as odds/hazard ratios [OR or HR; (95% confidence intervals).

Results

882/1941 (45.4%) patients had HRR≤12bpm. All-cause morbidity within 5 days of surgery was more common in 585/822 (71.2%) patients with HRR≤12bpm, compared to 718/1119 (64.2%) patients with HRR>12bpm (OR:1.38 (1.14–1.67); p = 0.001). HRR≤12bpm was associated with more frequent episodes of pulmonary (OR:1.31 (1.05–1.62);p = 0.02)), infective (OR:1.38 (1.10–1.72); p = 0.006), renal (OR:1.91 (1.30–2.79); p = 0.02)), cardiovascular (OR:1.39 (1.15–1.69); p<0.001)), neurological (OR:1.73 (1.11–2.70); p = 0.02)) and pain morbidity (OR:1.38 (1.14–1.68); p = 0.001) within 5 days of surgery.

Conclusions

Multi-organ dysfunction is more common in surgical patients with cardiac vagal dysfunction, defined as HRR ≤ 12 bpm after preoperative cardiopulmonary exercise testing.

Clinical trial registry

ISRCTN88456378.

Chronotropic incompetence and myocardial injury after noncardiac surgery: planned secondary analysis of a prospective observational international cohort study

BACKGROUND

Physiological measures of heart failure are common in surgical patients, despite the absence of a diagnosis. Heart rate (HR) increases during exercise are frequently blunted in heart failure (termed chronotropic incompetence), which primarily reflects beta-adrenoreceptor dysfunction. We examined whether chronotropic incompetence was associated with myocardial injury after noncardiac surgery.

METHODS

This was a predefined analysis of an international cohort study where participants aged ≥40 yr underwent symptom-limited cardiopulmonary exercise testing before noncardiac surgery. Chronotropic incompetence was defined as the ratio of increase in HR during exercise to age-predicted maximal increase in HR <0.6. The primary outcome was myocardial injury within 3 days after surgery, defined by high-sensitivity troponin assays >99th centile. Explanatory variables were biomarkers for heart failure (ventilatory efficiency slope [minute ventilation/carbon dioxide production] ≥34; peak oxygen consumption ≤14 ml kg-1 min-1; HR recovery ≤6 beats min-1 decrease 1 min post-exercise; preoperative N-terminal pro-B-type natriuretic peptide [NT pro-BNP] >300 pg ml-1). Myocardial injury was compared in the presence or absence of sympathetic (i.e. chronotropic incompetence) or parasympathetic (i.e. impaired HR recovery after exercise) thresholds indicative of dysfunction. Data are presented as odds ratios (ORs) (95% confidence intervals).

RESULTS

Chronotropic incompetence occurred in 396/1325 (29.9%) participants; only 16/1325 (1.2%) had a heart failure diagnosis. Myocardial injury was sustained by 162/1325 (12.2%) patients. Raised preoperative NT pro-BNP was more common when chronotropic incompetence was <0.6 (OR: 1.57 [1.11-2.23]; P=0.011). Chronotropic incompetence was not significantly associated with myocardial injury (OR: 1.05 [0.74-1.50]; P=0.78), independent of rate-limiting therapy. HR recovery <12 beats min-1 decrease after exercise was associated with myocardial injury in the presence (OR: 1.62 [1.05-2.51]; P=0.03) or absence (OR: 1.60 [1.06-2.39]; P=0.02) of chronotropic incompetence.

CONCLUSIONS

Chronotropic incompetence is common in surgical patients. In contrast to parasympathetic dysfunction which was associated with myocardial injury, preoperative chronotropic incompetence (suggestive of sympathetic dysfunction) was not associated with postoperative myocardial injury.

Assessment of need for lower level acuity critical care services at a tertiary acute care hospital in Canada: A prospective cohort study

PURPOSE

Critical care beds are commonly described in three levels (highest level 3, lowest level 1). We aimed to describe the actual level of care for patients assigned to level 2 in a tertiary hospital with inadequate level 1 bed capacity.

MATERIALS AND METHODS

Prospective cohort study with daily assessment of level of care. The primary outcome was the proportion of patients who could be triaged to level 1 for the entirety of their ICU stay. Secondary outcomes included the percentage of patients who could receive level 1 care on any given day.

RESULTS

289 patients originally classified as level 2 were assessed for the primary, and 335 for the secondary outcomes. 14.9% could be level 1 for their entire ICU stay. 20.6%, once appropriate for level 1, remained in that level for the rest of their ICU stay. 23.6% of the assessments were suitable for level 1 on any given day.

CONCLUSION

In a single centre, 14.9% of level 2 patients could have been cared for in a lower acuity bed for the entirety of their ICU stay. We believe this methodology is reproducible and can help resource allocation with regard to the high demand for critical care beds.

Cardiac vagal dysfunction and myocardial injury after non-cardiac surgery: a planned secondary analysis of the measurement of Exercise Tolerance before surgery study

Background

The aetiology of perioperative myocardial injury is poorly understood and not clearly linked to pre-existing cardiovascular disease. We hypothesised that loss of cardioprotective vagal tone [defined by impaired heart rate recovery ≤12 beats min⁻¹ (HRR ≤12) 1 min after cessation of preoperative cardiopulmonary exercise testing] was associated with perioperative myocardial injury.

Methods

We conducted a pre-defined, secondary analysis of a multi-centre prospective cohort study of preoperative cardiopulmonary exercise testing. Participants were aged ≥40 yr undergoing non-cardiac surgery. The exposure was impaired HRR (HRR≤12). The primary outcome was postoperative myocardial injury, defined by serum troponin concentration within 72 h after surgery. The analysis accounted for established markers of cardiac risk [Revised Cardiac Risk Index (RCRI), N-terminal pro-brain natriuretic peptide (NT pro-BNP)].

Results

A total of 1326 participants were included [mean age (standard deviation), 64 (10) yr], of whom 816 (61.5%) were male. HRR≤12 occurred in 548 patients (41.3%). Myocardial injury was more frequent amongst patients with HRR≤12 [85/548 (15.5%) vs HRR>12: 83/778 (10.7%); odds ratio (OR), 1.50 (1.08–2.08); P=0.016, adjusted for RCRI). HRR declined progressively in patients with increasing numbers of RCRI factors. Patients with ≥3 RCRI factors were more likely to have HRR≤12 [26/36 (72.2%) vs 0 factors: 167/419 (39.9%); OR, 3.92 (1.84–8.34); P<0.001]. NT pro-BNP greater than a standard prognostic threshold (>300 pg ml⁻¹) was more frequent in patients with HRR≤12 [96/529 (18.1%) vs HRR>12 59/745 (7.9%); OR, 2.58 (1.82–3.64); P<0.001].

Conclusions

Impaired HRR is associated with an increased risk of perioperative cardiac injury. These data suggest a mechanistic role for cardiac vagal dysfunction in promoting perioperative myocardial injury.

Selective decontamination of the digestive tract in critical care: a teenage angst or coming of age issue?

Selective decontamination of the digestive tract (SDD) has been with us since the early days of our specialty, and in some ways it marks our progression and maturation. How we have dealt with SDD to date ranges from “thorn in our side” to “elephant in the room”. With high quality multi-national studies underway, how we deal with these results will mark our final maturation to adulthood as a specialty.

Assessment of functional capacity before major non-cardiac surgery: an international, prospective cohort study

BACKGROUND

Functional capacity is an important component of risk assessment for major surgery. Doctors' clinical subjective assessment of patients' functional capacity has uncertain accuracy. We did a study to compare preoperative subjective assessment with alternative markers of fitness (cardiopulmonary exercise testing [CPET], scores on the Duke Activity Status Index [DASI] questionnaire, and serum N-terminal pro-B-type natriuretic peptide [NT pro-BNP] concentrations) for predicting death or complications after major elective non-cardiac surgery.

METHODS

We did a multicentre, international, prospective cohort study at 25 hospitals: five in Canada, seven in the UK, ten in Australia, and three in New Zealand. We recruited adults aged at least 40 years who were scheduled for major non-cardiac surgery and deemed to have one or more risk factors for cardiac complications (eg, a history of heart failure, stroke, or diabetes) or coronary artery disease. Functional capacity was subjectively assessed in units of metabolic equivalents of tasks by the responsible anaesthesiologists in the preoperative assessment clinic, graded as poor (<4), moderate (4-10), or good (>10). All participants also completed the DASI questionnaire, underwent CPET to measure peak oxygen consumption, and had blood tests for measurement of NT pro-BNP concentrations. After surgery, patients had daily electrocardiograms and blood tests to measure troponin and creatinine concentrations until the third postoperative day or hospital discharge. The primary outcome was death or myocardial infarction within 30 days after surgery, assessed in all participants who underwent both CPET and surgery. Prognostic accuracy was assessed using logistic regression, receiver-operating-characteristic curves, and net risk reclassification.

FINDINGS

Between March 1, 2013, and March 25, 2016, we included 1401 patients in the study. 28 (2%) of 1401 patients died or had a myocardial infarction within 30 days of surgery. Subjective assessment had 19·2% sensitivity (95% CI 14·2-25) and 94·7% specificity (93·2-95·9) for identifying the inability to attain four metabolic equivalents during CPET. Only DASI scores were associated with predicting the primary outcome (adjusted odds ratio 0·96, 95% CI 0·83-0·99; p=0·03).

INTERPRETATION

Subjectively assessed functional capacity should not be used for preoperative risk evaluation. Clinicians could instead consider a measure such as DASI for cardiac risk assessment.

FUNDING

Canadian Institutes of Health Research, Heart and Stroke Foundation of Canada, Ontario Ministry of Health and Long-Term Care, Ontario Ministry of Research, Innovation and Science, UK National Institute of Academic Anaesthesia, UK Clinical Research Collaboration, Australian and New Zealand College of Anaesthetists, and Monash University.

Feasibility of the electrolarynx for enabling communication in the chronically critically ill: The EECCHO study

PURPOSE

To assess feasibility of producing intelligible and comprehensible speech with an electrolarynx; measure anxiety, communication ease, and satisfaction before/after electrolarynx training; and identify barriers/facilitators.

METHODS

We included tracheostomized adults from 3 units following commands, reading English, and mouthing words. On enrolment, we measured anxiety, ease, and satisfaction with communication. We gave electrolarynx instruction for ≤5 days then 2 independent raters assessed intelligibility, sentence comprehensibility (9-point difficulty scale), and Electrolarynx Effectiveness Score (EES), and re-evaluated anxiety, communication ease, and satisfaction. Interviews explored barriers/facilitators.

MEASUREMENTS AND MAIN RESULTS

We recruited 24 participants (Jan2015-Dec2016). Mean (SD) intelligibility was 45%(18%) words correct: 57%(21%) when facing. Mean comprehension difficulty was 6.4(2.0) overall, indicating moderate difficulty (5.5(2.5) scored visualizing). Mean EES was 2.9(1.0) (3 = improved lip-reading through recognizable sounds). Anxiety decreased from median 3.8 to 2.0 (P = .007). Communication was rated easier (median 15 vs 12, P = .04) whereas satisfaction remained similar (P = .06). Facilitators included device friendliness, patient independence, and word intelligibility. Barriers were patient weakness, difficulty positioning the device, and limited sentence as opposed to word intelligibility.

CONCLUSION

The electrolarynx may aid intelligible speech for some tracheostomized patients if the communication partner can visualize the users face, and reduce anxiety and make patient perceived communication easier.

Second Medical Opinions in End-of-Life Disputes in Critical Care: An Ethics-Based Approach

Requests for a second medical opinion (SMO) by patients or substitute decision-makers (SDMs) can arise during end-of-life disputes in critical care. Such disagreements between patients or SDMs and physicians often pertain to specific elements of the decision-making process related to withholding or withdrawing of life-sustaining treatments. When these disputes occur in the critical care setting in Canada, practicalities and policy barriers prevent an SDM from obtaining an SMO without support from healthcare providers; moreover, in a majority of these cases the SDM will require the facilitation of a physician who is often the same individual with whom they are in conflict. Institutional and a national society's policy statements propose SMOs as an important component of a conflict resolution process for end-of-life disputes (Bosslet et al. 2015; Singer et al. 2001). However, these policies do not provide specific guidance to physicians on how to fairly consider SMO requests. Given the vulnerable position of patients and their SDMs in the critical care context and in order to promote fairness, physicians should apply consistent standards in deciding whether to facilitate a request for an SMO. To guide physicians' decision-making and inform future policy development, we propose three ethical principles for considering SDM requests for an SMO in critical care at the end of life.

Selective digestive decontamination in critically ill children: A survey of Canadian providers

BACKGROUND

Selective digestive decontamination of the digestive tract involves the routine administration of oral, gastric, and intravenous antibiotics to mechanically ventilated children to prevent hospital-acquired infections. It has a strong evidence base in adults, with limited pediatric evidence. Current utilization of this intervention among pediatric physicians in North America is unknown.

METHODS

An electronic survey administered to pediatric critical care and pediatric infectious disease providers in Canada. Participants were surveyed on current institutional practices, their current knowledge of the evidence base, and perceptions of the risks and benefits of the intervention. Descriptive statistics were utilized.

RESULTS

50 out of 143 (35%) surveyed responded. No hospital in Canada routinely performs SDD and the majority of respondents (74%) have neutral opinions on the subject of SDD. There was concern for increasing antibiotic resistance (43%) and some disagreement with the intravenous component of SDD (46%). The majority of respondents stated a need for pediatric-specific evidence before integrating SDD into their practice, even if further, large adult RCTs were performed.

CONCLUSION

Among surveyed providers, there is little knowledge and no use of selective digestive decontamination for the prevention of hospital-acquired infections. Before interventional studies are performed in pediatric practice, there is a need for study of facilitators, barriers and acceptability of SDD in practice.

The RECOVER Program: Disability Risk Groups and 1-Year Outcome after 7 or More Days of Mechanical Ventilation

RATIONALE

Disability risk groups and 1-year outcome after greater than or equal to 7 days of mechanical ventilation (MV) in medical/surgical intensive care unit (ICU) patients are unknown and may inform education, prognostication, rehabilitation, and study design.

OBJECTIVES

To stratify patients for post-ICU disability and recovery to 1 year after critical illness.

METHODS

We evaluated a multicenter cohort of 391 medical/surgical ICU patients who received greater than or equal to 1 week of MV at 7 days and 3, 6, and 12 months after ICU discharge. Disability risk groups were identified using recursive partitioning modeling.

MEASUREMENTS AND MAIN RESULTS

The 7-day post-ICU Functional Independence Measure (FIM) determined the recovery trajectory to 1-year after ICU discharge and was an independent risk factor for 1-year mortality. The 7-day post-ICU FIM was predicted by age and ICU length of stay. By 2 weeks of MV, ICU patients could be stratified into four disability groups characterized by increasing risk for post ICU disability, ICU and post-ICU healthcare use, and disposition. Patients less than 42 years with ICU length of stay less than 2 weeks had the best function and fewest deaths at 1 year compared with patients greater than 66 years with ICU length of stay greater than 2 weeks who sustained the worst disability and 40% 1-year mortality. Depressive symptoms (17%) and post-traumatic stress disorder (18%) persisted at 1 year.

CONCLUSIONS

ICU survivors of greater than or equal to 1 week of MV may be stratified into four disability groups based on age and ICU length of stay. These groups determine 1-year recovery and healthcare use and are independent of admitting diagnosis and illness severity. Clinical trial registered with www.clinicaltrials.gov (NCT 00896220).