Ventilator Weaning and Extubation

Increasing evidence supports specific approaches to liberate patients from invasive ventilation including the use of liberation protocols, inspiratory assistance during spontaneous breathing trials (SBTs), early extubation of patients with chronic obstructive pulmonary disease to noninvasive ventilation, and prophylactic use of noninvasive support strategies after extubation. Additional research is needed to elucidate the best criteria to identify patients who are ready to undergo an SBT and to inform optimal screening frequency, the best SBT technique and duration, extubation assessments, and extubation decision-making. Additional clarity is also needed regarding the optimal timing to measure and report extubation success.

Glycemic Variability As a Prognostic Factor for Mortality in Patients With Critical Illness: A Systematic Review and Meta-Analysis

OBJECTIVES

To perform a systematic review and meta-analysis to evaluate the association of various measures of glycemic variability, including time-domain and complexity-domain, with short-term mortality in patients with critical illness.

DATA SOURCES

We searched Embase Classic +, MEDLINE, and the Cochrane Database of Systematic Reviews from inception to November 3, 2023.

STUDY SELECTION

We included English language studies that assessed metrics of glycemic variation or complexity and short-term mortality in patients admitted to the ICU.

DATA EXTRACTION

Two authors performed independent data abstraction and risk-of-bias assessments. We used a random-effects model to pool binary and continuous data and summarized estimates of effect using odds ratios and mean difference. We used the Quality in Prognosis Studies tool to assess risk of bias and the Grading of Recommendations, Assessment, Development and Evaluations to assess certainty of pooled estimates.

DATA SYNTHESIS

We included 41 studies (n = 162,259). We demonstrate that increased sd, coefficient of variance, glycemic lability index, and decreased time in range are probably associated with increased mortality in critically ill patients (moderate certainty) and that increased mean absolute glucose, mean amplitude of glycemic excursion, and detrended fluctuation analysis may be associated with increased mortality (low certainty).

CONCLUSIONS

We found a consistent association between increased measures of glycemic variability and higher short-term mortality in patient with critical illness. Further research should focus on standardized measurements of glycemic variation and complexity, along with their utility as therapeutic targets and prognostic markers.

Guiding principles and proposed classification system for the responsible adoption of artificial intelligence in scientific writing in medicine

The integration of large language models (LLMs) and artificial intelligence (AI) into scientific writing, especially in medical literature, presents both unprecedented opportunities and inherent challenges. This manuscript evaluates the transformative potential of LLMs for the synthesis of information, linguistic enhancements, and global knowledge dissemination. At the same time, it raises concerns about unintentional plagiarism, the risk of misinformation, data biases, and an over-reliance on AI. To address these, we propose governing principles for AI adoption that ensure integrity, transparency, validity, and accountability. Additionally, guidelines for reporting AI involvement in manuscript development are delineated, and a classification system to specify the level of AI assistance is introduced. This approach uniquely addresses the challenges of AI in scientific writing, emphasizing transparency in authorship, qualification of AI involvement, and ethical considerations. Concerns regarding access equity, potential biases in AI-generated content, authorship dynamics, and accountability are also explored, emphasizing the human author's continued responsibility. Recommendations are made for fostering collaboration between AI developers, researchers, and journal editors and for emphasizing the importance of AI's responsible use in academic writing. Regular evaluations of AI's impact on the quality and biases of medical manuscripts are also advocated. As we navigate the expanding realm of AI in scientific discourse, it is crucial to maintain the human element of creativity, ethics, and oversight, ensuring that the integrity of scientific literature remains uncompromised.

A 20-Year Update on the Practice of Thoracic Surgery in Canada: A Survey of the Canadian Association of Thoracic Surgeons

Background

This study provides an update to a landmark 2004 report describing demographics, training, and trends in adherence to thoracic surgery practice standards in Canada.

Methods

An updated questionnaire was administered to all members of the Canadian Association of Thoracic Surgeons via email (n=142, compared to n=68 in 2004). Our report incorporates internal data from Ontario Health and the Canadian Partnership Against Cancer.

Results

Forty-eight surgeons completed the survey (male, 70.8%; mean±standard deviation age, 50.3±9.3 years). This represents a 33.8% response rate, compared to 64.7% in 2004. Most surgeons (69%) served a patient population of over 1 million per center; 32%-34% reported an on-call ratio of 1:4-1:5 days, and the average weekly hours worked was 56.4±11.9. Greater access to dedicated geographic units per center (73% in 2021 vs. 53% in 2004) has improved thoracic-associated services and house staff, notably endoscopy units (100% vs. 91%), with 73% of respondents having access to both endobronchial and endoscopic ultrasound. Access to thoracic radiology has also improved, particularly regarding positron emission tomography scanners per center (76.9% vs. 13%). Annual case volumes for lung (255 vs. 128), esophageal (41 vs. 19), and mediastinal resections (30 vs. 13), along with hiatal hernia repair (45 vs. 20), have increased substantially despite reports of operating room availability and radiology as rate-limiting steps.

Conclusion

This survey characterizes compliance with current practice standards, addressing the needs of thoracic surgeons across Canada. Over 85% of respondents were aware of the 2004 compliance paper, and 35% had applied for resources and equipment in response.

Cardiac autonomic modulation in individuals with controlled and uncomplicated hypertension during exercise-heat stress

TAKE-HOME MESSAGE

During short bouts of light-to-vigorous exercise in the heat, controlled and uncomplicated hypertension did not significantly modulate HRV in physically active individuals. These findings can be used to refine guidance on use of exercise for hypertension management in the heat.

Frequency of screening and SBT Technique Trial-North American Weaning Collaboration (FAST-NAWC): an update to the protocol and statistical analysis plan

BACKGROUND

This update summarizes key changes made to the protocol for the Frequency of Screening and Spontaneous Breathing Trial (SBT) Technique Trial-North American Weaning Collaborative (FAST-NAWC) trial since the publication of the original protocol. This multicenter, factorial design randomized controlled trial with concealed allocation, will compare the effect of both screening frequency (once vs. at least twice daily) to identify candidates to undergo a SBT and SBT technique [pressure support + positive end-expiratory pressure vs. T-piece] on the time to successful extubation (primary outcome) in 760 critically ill adults who are invasively ventilated for at least 24 h in 20 North American intensive care units.

METHODS/DESIGN

Protocols for the pilot, factorial design trial and the full trial were previously published in J Clin Trials ( https://doi.org/10.4172/2167-0870.1000284 ) and Trials (https://doi: 10.1186/s13063-019-3641-8). As planned, participants enrolled in the FAST pilot trial will be included in the report of the full FAST-NAWC trial. In response to the onset of the coronavirus disease of 2019 (COVID-19) pandemic when approximately two thirds of enrollment was complete, we revised the protocol and consent form to include critically ill invasively ventilated patients with COVID-19. We also refined the statistical analysis plan (SAP) to reflect inclusion and reporting of participants with and without COVID-19. This update summarizes the changes made and their rationale and provides a refined SAP for the FAST-NAWC trial. These changes have been finalized before completion of trial follow-up and the commencement of data analysis.

TRIAL REGISTRATION

Clinical Trials.gov NCT02399267.

Continuous Monitoring of Entropy Production and Entropy Flow in Humans Exercising under Heat Stress

Complex living systems, such as the human organism, are characterized by their self-organized and dissipative behaviors, where irreversible processes continuously produce entropy internally and export it to the environment; however, a means by which to measure human entropy production and entropy flow over time is not well-studied. In this article, we leverage prior experimental data to introduce an experimental approach for the continuous measurement of external entropy flow (released to the environment) and internal entropy production (within the body), using direct and indirect calorimetry, respectively, for humans exercising under heat stress. Direct calorimetry, performed with a whole-body modified Snellen calorimeter, was used to measure the external heat dissipation from the change in temperature and relative humidity between the air outflow and inflow, from which was derived the rates of entropy flow of the body. Indirect calorimetry, which measures oxygen consumption and carbon dioxide production from inspired and expired gases, was used to monitor internal entropy production. A two-compartment entropy flow model was used to calculate the rates of internal entropy production and external entropy flow for 11 middle-aged men during a schedule of alternating exercise and resting bouts at a fixed metabolic heat production rate. We measured a resting internal entropy production rate of (0.18 ± 0.01) W/(K·m2) during heat stress only, which is in agreement with published measurements. This research introduces an approach for the real-time monitoring of entropy production and entropy flow in humans, and aims for an improved understanding of human health and illness based on non-equilibrium thermodynamics.

Predictors of Noninvasive Ventilation Failure in the Post-Extubation Period: A Systematic Review and Meta-Analysis

OBJECTIVES

To identify factors associated with failure of noninvasive ventilation (NIV) in the post-extubation period.

DATA SOURCES

We searched Embase Classic +, MEDLINE, and the Cochrane Database of Systematic Reviews from inception to February 28, 2022.

STUDY SELECTION

We included English language studies that provided predictors of post-extubation NIV failure necessitating reintubation.

DATA EXTRACTION

Two authors conducted data abstraction and risk-of-bias assessments independently. We used a random-effects model to pool binary and continuous data and summarized estimates of effect using odds ratios (ORs) mean difference (MD), respectively. We used the Quality in Prognosis Studies tool to assess risk of bias and the Grading of Recommendations, Assessment, Development and Evaluations to assess certainty.

DATA SYNTHESIS

We included 25 studies ( n = 2,327). Illness-related factors associated with increased odds of post-extubation NIV failure were higher critical illness severity (OR, 3.56; 95% CI, 1.96-6.45; high certainty) and a diagnosis of pneumonia (OR, 6.16; 95% CI, 2.59-14.66; moderate certainty). Clinical and biochemical factors associated with moderate certainty of increased risk of NIV failure post-extubation include higher respiratory rate (MD, 1.54; 95% CI, 0.61-2.47), higher heart rate (MD, 4.46; 95% CI, 1.67-7.25), lower Pa o2 :F io2 (MD, -30.78; 95% CI, -50.02 to -11.54) 1-hour after NIV initiation, and higher rapid shallow breathing index (MD, 15.21; 95% CI, 12.04-18.38) prior to NIV start. Elevated body mass index was the only patient-related factor that may be associated with a protective effect (OR, 0.21; 95% CI, 0.09-0.52; moderate certainty) on post-extubation NIV failure.

CONCLUSIONS

We identified several prognostic factors before and 1 hour after NIV initiation associated with increased risk of NIV failure in the post-extubation period. Well-designed prospective studies are required to confirm the prognostic importance of these factors to help further guide clinical decision-making.

Use of multidisciplinary positive deviance seminars to improve efficiency in a high-volume arthroplasty practice: a pilot study

BACKGROUND

Positive deviance (PD) seminars, which have shown excellent results in improving the quality of surgical practices, use individual performance feedback to identify team members who outperform their peers; the strategies from those with exemplary performance are used to improve team members' practices. Our study aimed to use the PD approach with arthroplasty surgeons and nurses to identify multidisciplinary strategies and recommendations to improve operating room (OR) efficiency.

METHODS

We recruited 5 surgeons who performed high-volume primary arthroplasty and had participated in 4-joint rooms since 2012, and 29 nurses who had participated in 4-joint rooms and in at least 16 cases in our data set. Three 1-hour PD sessions were held in February and March 2021: 1 with surgeons, 1 with nurses, and 1 with both surgeons and nurses to select recommendations for implementation. The sessions were led by a member of the nonorthopedic surgical faculty who was familiar with the subjects discussed and with PD seminars. To determine the success of the recommendations, we compared OR efficiency before and after implementation. We defined success as performance of 4 joint procedures within 8 hours.

RESULTS

Eleven recommendations were recorded from the session with nurses and 7 from the session with surgeons, of which 11 were selected for implementation. During the month after implementation, there were great improvements across all time intervals of surgical procedures, with the greatest improvements seen in mean anesthesia preparation time in the room (4.51 min [26.3%]), mean procedure duration (9.75 min [14.0%]) and mean anesthesia finish time (5.78 min [44.0%]) (all p < 0.001). The total time saved per day was 49.84 minutes; this led to a success rate of 69.0%, a relative increase of 73.8% from our 2012-2020 success rate of 39.7% (p < 0.001).

CONCLUSION

The recommendations and increased motivation owing to the individualized feedback reduced time spent per case, allowing more days to finish on time. Positive deviance seminars offer an inexpensive, efficient and collegial means for process improvement in the OR.

Multicentre positive deviance to reduce adverse events and length of stay after pulmonary resection

BACKGROUND

Postoperative adverse events (AEs) following pulmonary resection enormously impact patient well-being, length of stay (LOS) and healthcare costs. Standardised AE data collection can be used to identify positive outliers demonstrating positive deviance (PD) who may be helpful to inform the best practice. Here, we describe our initial experience of a novel quality improvement process using PD to reduce LOS and AEs.

METHODS

AE rates and LOS were collected from four centres (2014-2020) using a common dictionary. Surgeons repeatedly participated in 60 to 90 min seminars consisting of the following process: identify outcome and procedure targeted, review relevant best evidence literature, view all data anonymised by surgeon or centre (if multicentre), choose and reveal identity of best performance PD outliers, who discuss their management principles while all receive self-evaluation reports, followed by collegial discussion to generate consensus recommendations, voted by all. We assessed overall impact on AEs and LOS using aggregate data in a before/after analysis.

RESULTS

A total of 131 surgeons (average 12/seminar) participated in 11 PD seminars (8 local and 3 multicentre), yielding 85 consensus recommendation (average 8/seminar). Median LOS following lobectomy decreased from 4.0 to 3.0 days (p=0.04) following local PD seminars and from 4.0 to 3.5 days (p=0.11) following multicentre seminars. Trends for reductions in multiple AE rates were also observed.

CONCLUSION

While limited by the longitudinal design, these findings provide preliminary support for this data-driven, collegial and actionable quality improvement process to help standardise and improve patient care, and merits further more rigorous investigation.

Heart Rate Variability in Children with Moderate and Severe Traumatic Brain Injury: A Prospective Observational Study

The aim of this study was to assess the feasibility of continuous monitoring of heart rate variability (HRV) in children with traumatic brain injury (TBI) hospitalized in a pediatric intensive care unit (PICU) and collect preliminary data on the association between HRV, neurological outcome, and complications. This is a prospective observational cohort study in a tertiary academic PICU. Children admitted to the PICU ≤24 hours after moderate or severe TBI were included in the study. Children suspected of being brain dead at PICU entry or with a pacemaker were excluded. Children underwent continuous monitoring of electrocardiographic (ECG) waveforms over 7 days post-TBI. HRV analysis was performed retrospectively, using a standardized, validated HRV analysis software (CIMVA). The occurrence of medical complications (“event”: intracranial hypertension, cerebral hypoperfusion, seizure, and cardiac arrest) was prospectively documented. Outcome of children 6 months post-TBI was assessed using the Glasgow Outcome Scale – Extended Pediatric (GOS-E Peds). Fifteen patients were included over a 20-month period. Thirteen patients had ECG recordings available and 4 had >20% of missing ECG data. When ECG was available, HRV calculation was feasible (average 88%; range 70–97%). Significant decrease in overall HRV coefficient of variation and Poincaré SD2 (p < 0.05) at 6 hours post–PICU admission was associated with an unfavorable outcome (defined as GOS-E Peds ≥ 3, or a deterioration of ≥2 points over baseline score). Several HRV metrics exhibited significant and nonsignificant variation in HRV during event. This study demonstrates that it is feasible to monitor HRV in the PICU provided ECG data are available; however, missing ECG data are not uncommon. These preliminary data suggest that altered HRV is associated with unfavorable neurological outcome and in-hospital medical complications. Larger prospective studies are needed to confirm these findings and to explore if HRV offers reliable and clinically useful prediction data that may help clinical decision making.

Barriers and Facilitators to the Implementation and Adoption of a Continuous Quality Improvement Program in Surgery: A Case Study

INTRODUCTION

As postoperative adverse events (AEs) drive worsened patient experience, longer length of stay, and increased costs of care, surgeons have long sought to engage in innovative approaches aimed at reducing AEs to improve the quality and safety of surgical care. While data-driven AE performance measurement and feedback (PMF) as a form of continuing professional development (CPD) has been presented as a possible approach to continuous quality improvement (CQI), little is known about the barriers and facilitators that influence surgeons' engagement and uptake of these CPD programs. The purpose of this knowledge translation informed CPD study was to examine surgeons' perspectives of the challenges and facilitators to participating in surgical CQI with the broader objective of enhancing future improvements of such CPD interventions.

METHODS

Using Everett Rogers diffusion of innovations framework as a sampling frame, the participants were recruited across five surgical divisions. An exploratory case study approach, including in-depth semistructured interviews, was employed. Interview transcripts were analyzed and directly coded using the Theoretical Domains Framework.

RESULTS

Directed coding yielded a total of 527 coded barriers and facilitators to behavior change pertaining to the implementation and adoption of PMF with the majority of barriers and facilitators coded in four key theoretical domains environmental context and resources, social influences, knowledge, and beliefs about consequences. A key barrier was the lack of support from the hospital necessitating surgeons' self-funding their own PMF programs. Facilitators included having a champion to drive CQI and using seminars to facilitate discussions around CQI principles and practices.

DISCUSSION

This study identified multiple barriers and facilitators to surgeons' engagement and uptake of a data-driven PMF system in surgery. A key finding of the study was the identification of the influential role of positive deviance seminars as a quality improvement and patient safety mechanism that encourages surgeon engagement in PMF systems.

Research interrupted: applying the CONSERVE 2021 Statement to a randomized trial of rehabilitation during critical illness affected by the COVID-19 pandemic

RATIONALE

The COVID-19 pandemic disrupted non-COVID critical care trials globally as intensive care units (ICUs) prioritized patient care and COVID-specific research. The international randomized controlled trial CYCLE (Critical Care Cycling to Improve Lower Extremity Strength) was forced to halt recruitment at all sites in March 2020, creating immediate challenges. We applied the CONSERVE (CONSORT and SPIRIT Extension for RCTs Revised in Extenuating Circumstance) statement as a framework to report the impact of the pandemic on CYCLE and describe our mitigation approaches.

METHODS

On March 23, 2020, the CYCLE Methods Centre distributed a standardized email to determine the number of patients still in-hospital and those requiring imminent 90-day endpoint assessments. We assessed protocol fidelity by documenting attempts to provide the in-hospital randomized intervention (cycling or routine physiotherapy) and collect the primary outcome (physical function 3-days post-ICU discharge) and 90-day outcomes. We advised sites to prioritize data for the study's primary outcome. We sought feedback on pandemic barriers related to trial procedures.

RESULTS

Our main Methods Centre mitigation strategies included identifying patients at risk for protocol deviations, communicating early and frequently with sites, developing standardized internal tools focused on high-risk points in the protocol for monitoring patient progress, data entry, and validation, and providing guidance to conduct some research activities remotely. For study sites, our strategies included determining how institutional pandemic research policies applied to CYCLE, communicating with the Methods Centre about capacity to continue any part of the research, and developing contingency plans to ensure the protocol was delivered as intended. From 15 active sites (12 Canada, 2 US, 1 Australia), 5 patients were still receiving the study intervention in ICUs, 6 required primary outcomes, and 17 required 90-day assessments. With these mitigation strategies, we attempted 100% of ICU interventions, 83% of primary outcomes, and 100% of 90-day assessments per our protocol.

CONCLUSIONS

We retained all enrolled patients with minimal missing data using several time-sensitive strategies. Although CONSERVE recommends reporting only major modifications incurred by extenuating circumstances, we suggest that it also provides a helpful framework for reporting mitigation strategies with the goal of improving research transparency and trial management.

TRIAL REGISTRATION

NCT03471247. Registered on March 20, 2018.

Routine systematic sampling versus targeted sampling during endobronchial ultrasound: A randomized feasibility trial

OBJECTIVE

Triple normal lymph nodes, appearing benign on computed tomography, positron emission tomography, and endobronchial ultrasound, have less than a 6% probability of malignancy. We hypothesized that targeted sampling (TS), which omits biopsy of triple normal lymph nodes during endobronchial ultrasound, is not an inferior staging strategy to systematic sampling (SS) of all lymph nodes.

METHODS

A prospective randomized feasibility trial was conducted to decide on the progression to a pan-Canadian trial comparing TS with SS. Patients with cN0-N1 non-small cell lung cancer undergoing endobronchial ultrasound were randomized to TS or SS. Lymph nodes in the TS arm crossed over to receive SS. Progression criteria included recruitment rate (70% minimum), procedure length (no significant increase for TS), and incidence of missed nodal metastasis (<6%). Mann-Whitney U test and McNemar's test on paired proportions were used for statistical comparisons.

RESULTS

The progression criterion of 70% recruitment rate was achieved early, triggering a planned early stoppage of the trial. Nineteen patients were allocated to each arm. The median procedure length for TS was significantly shorter than SS (3.07 vs 19.07 minutes; P < .001). After crossover analysis, 5.45% (95% confidence interval, 1.87-14.85) of lymph nodes in the TS arm were upstaged from N0 to N2, but this incidence of missed nodal metastasis was below the 6% threshold. During surgical resection, the nodal upstaging incidence from N0 to N2 was 0% for 15 lymph nodes in each arm.

CONCLUSIONS

Progression criteria to a pan-Canadian, noninferiority crossover trial comparing TS with SS have been met, and such a trial is warranted.

Intravenous Vitamin C in Adults with Sepsis in the Intensive Care Unit

BACKGROUND

Studies that have evaluated the use of intravenous vitamin C in adults with sepsis who were receiving vasopressor therapy in the intensive care unit (ICU) have shown mixed results with respect to the risk of death and organ dysfunction.

METHODS

In this randomized, placebo-controlled trial, we assigned adults who had been in the ICU for no longer than 24 hours, who had proven or suspected infection as the main diagnosis, and who were receiving a vasopressor to receive an infusion of either vitamin C (at a dose of 50 mg per kilogram of body weight) or matched placebo administered every 6 hours for up to 96 hours. The primary outcome was a composite of death or persistent organ dysfunction (defined by the use of vasopressors, invasive mechanical ventilation, or new renal-replacement therapy) on day 28.

RESULTS

A total of 872 patients underwent randomization (435 to the vitamin C group and 437 to the control group). The primary outcome occurred in 191 of 429 patients (44.5%) in the vitamin C group and in 167 of 434 patients (38.5%) in the control group (risk ratio, 1.21; 95% confidence interval [CI], 1.04 to 1.40; P = 0.01). At 28 days, death had occurred in 152 of 429 patients (35.4%) in the vitamin C group and in 137 of 434 patients (31.6%) in the placebo group (risk ratio, 1.17; 95% CI, 0.98 to 1.40) and persistent organ dysfunction in 39 of 429 patients (9.1%) and 30 of 434 patients (6.9%), respectively (risk ratio, 1.30; 95% CI, 0.83 to 2.05). Findings were similar in the two groups regarding organ-dysfunction scores, biomarkers, 6-month survival, health-related quality of life, stage 3 acute kidney injury, and hypoglycemic episodes. In the vitamin C group, one patient had a severe hypoglycemic episode and another had a serious anaphylaxis event.

CONCLUSIONS

In adults with sepsis receiving vasopressor therapy in the ICU, those who received intravenous vitamin C had a higher risk of death or persistent organ dysfunction at 28 days than those who received placebo. (Funded by the Lotte and John Hecht Memorial Foundation; LOVIT ClinicalTrials.gov number, NCT03680274.).

Early oral intake and early removal of nasogastric tube post-esophagectomy: A systematic review and meta-analysis

BACKGROUND

Early oral intake (EOI: initiated within 1 day) and early nasogastric tube removal (ENR: removed ≤2 days) post-esophagectomy is controversial and subject to significant variation.

AIM

Our aim is to provide the most up-to-date evidence from published randomized controlled trials (RCTs) addressing both topics.

METHODS

We searched MEDLINE and Embase (1946-06/2019) for RCTs that investigated the effect of EOI and/or ENR post-esophagectomy with gastric conduit for reconstruction. Our main outcomes of interest were anastomotic leak, aspiration pneumonia, mortality, and length of hospital stay (LOS). Pooled mean differences (MD) and risk ratios (RR) estimates were obtained using a DerSimonian random effects model.

RESULTS

Two reviewers screened 613 abstracts and identified 6 RCTs eligible for inclusion; 2 regarding EOI and 4 for ENR. For EOI (2 studies, n = 389), was not associated with differences in risk of: anastomotic leak (RR: 1.01; 95% CI: 0.407, 2.500; I2 : 0%), aspiration pneumonia (RR: 1.018; 95% CI: 0.407, 2.500), mortality (RR: 1.00; 95% CI: 0.020, 50.0). The LOS was significantly shorter in the EOI group: LOS (MD: -2.509; 95% CI: -3.489, -1.529; I2 : 90.44%). For ENR (4 studies, n = 295), ENR (removed at POD0-2 vs. 5-8 days) was not associated with differences in risk of: anastomotic leak (RR: 1.11; 95% CI 0.336, 3.697; I2 : 25.75%) and pneumonia group (RR: 1.11; 95% CI: 0.336, 3.697; I2 : 25.75%), mortality (RR: 0.87; 95% CI: 0.328, 2.308; I2 : 0%)or LOS (MD: 1.618; 95% CI: -1.447, 4.683; I2 : 73.03%).

CONCLUSIONS

Our analysis showed that EOI as well as ENR post-esophagectomy do not significantly increase the risk of anastomotic leak, pneumonia, and mortality. The LOS was significantly shorter in the EOI group, and there was no significant difference in the ENR group. A paucity of RCTs has evaluated this question, highlighting the need for further high-quality evidence to address these vital aspects to post-esophagectomy care.

SYSTEMATIC REVIEW REGISTRATION

CRD42019138600.

Evolution of Process and Outcome Measures during an Enhanced Recovery after Thoracic Surgery Program

Background

A time course analysis was undertaken to evaluate how perioperative process-of-care and outcome measures evolved after implementation of an enhanced recovery after thoracic surgery (ERATS) program.

Methods

Outcome and process-of-care measures were compared between patients undergoing major elective thoracic surgery during a 9-month pre-ERATS implementation period to those at 1–3, 4–6, and 7–9 months post-ERATS implementation. Outcome measures included length of stay, the 30-day readmission rate, 30-day emergency department visits, and minor and major adverse events. Process measures included first time to activity, out-of-bed, ambulation, fluid diet, diet as tolerated, as well as removal of the first and last chest tube, epidural, patient-controlled analgesia, and Foley and intravenous catheters.

Results

In total, 704 patients (352 pre-ERATS, 352 post-ERATS) were included. Mobilization-related process measures, including time to first activity (16.5 vs. 6.8 hours, p<0.001), out-of-bed (17.6 vs. 8.9 hours, p<0.001), and ambulation (32.4 vs. 25.4 hours, p=0.04) saw statistically significant improvements by 1–3 months post-ERATS implementation compared to pre-ERATS. Time to Foley removal improved by 4–6 months post-ERATS (19.5 vs. 18.2 hours, p=0.003). Outcome measures, including the 30-day readmission rate and emergency department visits, steadily decreased post-ERATS. By 7–9 months post-ERATS, both minor (18.2% vs. 7.9%, p=0.009) and major (13.6% vs. 4.4%, p=0.007) adverse events demonstrated statistically significant improvements. Length of stay trended towards improvement from 6.2 days pre-ERATS to 4.8 days by 7–9 months post-ERATS (p=0.06).

Conclusion

The adoption of ERATS led to improvements in multiple process-of-care measures, which may collectively and gradually achieve optimization of clinical outcomes.

Noninvasive respiratory support following extubation in critically ill adults: a systematic review and network meta-analysis

PURPOSE

Systematic review and network meta-analysis to investigate the efficacy of noninvasive respiratory strategies, including noninvasive positive pressure ventilation (NIPPV) and high-flow nasal cannula (HFNC), in reducing extubation failure among critically ill adults.

METHODS

We searched databases from inception through October 2021 for randomized controlled trials (RCTs) evaluating noninvasive respiratory support therapies (NIPPV, HFNC, conventional oxygen therapy, or a combination of these) following extubation in critically ill adults. Two reviewers performed screening, full text review, and extraction independently. The primary outcome of interest was reintubation. We used GRADE to rate the certainty of our findings.

RESULTS

We included 36 RCTs (6806 patients). Compared to conventional oxygen therapy, NIPPV (OR 0.65 [95% CI 0.52-0.82]) and HFNC (OR 0.63 [95% CI 0.45-0.87]) reduced reintubation (both moderate certainty). Sensitivity analyses showed that the magnitude of the effect was highest in patients with increased baseline risk of reintubation. As compared to HFNC, no difference in incidence of reintubation was seen with NIPPV (OR 1.04 [95% CI 0.78-1.38], low certainty). Compared to conventional oxygen therapy, neither NIPPV (OR 0.8 [95% CI 0.61-1.04], moderate certainty) or HFNC (OR 0.9 [95% CI 0.66-1.24], low certainty) reduced short-term mortality. Consistent findings were demonstrated across multiple subgroups, including high- and low-risk patients. These results were replicated when evaluating noninvasive strategies for prevention (prophylaxis), but not in rescue (application only after evidence of deterioration) situations.

CONCLUSIONS

Our findings suggest that both NIPPV and HFNC reduced reintubation in critically ill adults, compared to conventional oxygen therapy. NIPPV did not reduce incidence of reintubation when compared to HFNC. These findings support the preventative application of noninvasive respiratory support strategies to mitigate extubation failure in critically ill adults, but not in rescue conditions.

Exploring the Effects of Yoga Therapy on Heart Rate Variability and Patient-Reported Outcomes After Cancer Treatment: A Study Protocol

BACKGROUND

Following cancer treatment, adults commonly report worsened patient-reported outcomes (PROs) such as anxiety, stress, depression, persistent and upsetting cognitive complaints, unrelenting fatigue, and reduced quality of life. Poorer PROs are associated with disrupted autonomic nervous system functioning as measured by heart rate variability (HRV), both of which have been associated with greater morbidity and mortality. Interventions to improve HRV and PROs among adults following cancer treatment are needed. Yoga therapy holds promise as an intervention to improve HRV and PROs. Therefore, we conducted a single-subject exploratory experimental study to investigate the effects of yoga therapy on HRV and specific PROs (ie, cancer-related fatigue, anxiety, cognitive function, depression, stress, quality of life) in adults treated for cancer. To reduce publication bias, improve reproducibility, and serve as a reference for forthcoming reporting of study results, we present the study protocol for this study herein.

METHODS

Participants were adults who completed cancer treatment that were recruited from the Ottawa Integrative Cancer Centre. Consenting and eligible participants received one 1:1 yoga therapy session (ie, 1 participant, 1 Yoga Therapist) and 6 weekly group-based yoga therapy sessions (ie, 2-3 participants, 1 Yoga Therapist). Participants completed assessments 7 times: 3 times prior to the program (ie, -6 weeks, -3 weeks, immediately prior to the 1:1 yoga therapy session), immediately following the 1:1 yoga therapy session, prior to the first group-based yoga therapy session, after the last group-based yoga therapy session, and at a 6-week follow-up. Hierarchical linear modeling will be used to test the average effects of the yoga therapy program across participants.

DISCUSSION

This study will explore several novel hypotheses, including whether yoga therapy can improve HRV and/or specific PROs among adults treated for cancer acutely (ie, during a 1:1 yoga therapy session) and/or through repeated exposure (ie, after completing 6 weeks of group-based yoga therapy). Although the findings will require confirmation or refutation in future trials, they may provide initial evidence that YT may benefit adults treated for cancer.

TRIAL REGISTRATION

ISRCTN registry, ISRCTN64763228. Registered on December 12, 2021. This trial was registered retrospectively. URL of trial registry record: https://www.isrctn.com/ISRCTN64763228.

The longitudinal impact of division-wide implementation of an enhanced recovery after thoracic surgery programme

OBJECTIVES

Data regarding enhanced recovery after thoracic surgery (ERATS) are sparse and inconsistent. This study aims to evaluate the effects of implementing an enhanced ERATS programme on postoperative outcomes, patient experience and quality of life (QOL).

METHODS

We conducted a prospective, longitudinal study evaluating 9 months before (pre-ERATS) and 9 months after (post-ERATS) a 3-month implementation of an ERATS programme in a single academic tertiary care centre. All patients undergoing major thoracic surgeries were included. The primary outcomes included length of stay (LOS), adverse events (AEs), 6-min walk test scores at 4 weeks, 30-day emergency room visits (without admission) and 30-day readmissions. The process-of-care outcomes included time to 'out-of-bed', independent ambulation, successful fluid intake, last chest tube removal and removal of urinary catheter. Perioperative anaesthesia-related outcomes were examined as well as patient experience and QOL scores.

RESULTS

The pre-ERATS group (n = 352 patients) and post-ERATS group (n = 352) demonstrated no differences in demographics. Post-ERATS patients had improved LOS (4.7 vs 6.2 days, P < 0.02), 6-min walk test scores (402 vs 371 m, P < 0.05) and 30-day emergency room visits (13.7% vs 21.6%, P = 0.03) with no differences in AEs and 30-day readmissions. Patients experienced shorter mean time to 'out-of-bed', independent ambulation, successful fluid intake, last chest tube removal and urinary catheter removal. There were no differences in postoperative analgesia administration, patient satisfaction and QOL scores.

CONCLUSIONS

ERATS implementation was associated with improved LOS, expedited feeding, ambulation and chest tube removal, without increasing AEs or readmissions, while maintaining a high level of patient satisfaction and QOL.

Standardized Postoperative Adverse Event Data Collection to Document, Inform, and Improve Patient Care

There is great potential for standardized postoperative adverse events data collection to document, inform, audit, and feedback, all to optimize patient care. Adverse events, defined as any deviation from expected recovery from surgery, have harmful implications for patients, their families, and clinicians. Postoperative adverse events occur frequently in thoracic surgery, predominately due to the high-stakes (ie, high potential for cure) and high-risk (ie, vital physiology and anatomy and preexisting disease) nature of the surgery. As discussed, engaging surgeons in audit and feedback practices informed by standardized data collection would generate consensus recommendations to reduce adverse events and improve patient outcomes.

External validity of a model to predict postoperative atrial fibrillation after thoracic surgery

OBJECTIVES

A prediction model developed by Passman et al. stratifies patients' risk of postoperative atrial fibrillation (POAF) after major non-cardiac thoracic surgery using 3 simple factors (sex, age and preoperative resting heart rate). The model has neither undergone external validation nor proven to be relevant in current thoracic surgery practice.

METHODS

A retrospective single-centre analysis of all patients who underwent major non-cardiac thoracic surgery (2008-2017) with prospective documentation of incidence and severity of POAF was used for external validation of Passman's derivation sample (published in 2005 with 856 patients). The model calibration was assessed by evaluating the incidence of POAF and patients' risk scores (0-6).

RESULTS

A total of 2054 patients were included. Among them, POAF occurred in 164 (7.9%), compared to 147 (17.2%) in Passman's study. Differences in our sample compared to Passman's sample included mean heart rate (75.7 vs 73.7 bpm, P < 0.001), proportion of patients with hypertension (46.1 vs 29.4%, P < 0.001), proportion of extensive lung resections, particularly pneumonectomy (6.1 vs 21%, P < 0.001) and proportion of minimally invasive surgeries (56.6% vs 0%). The model demonstrated a positive correlation between risk scores and POAF incidence (risk score 1.2% vs 6.16%).

CONCLUSIONS

The POAF model demonstrated good calibration in our population, despite a lower overall incidence of POAF compared to the derivation study. POAF rates were higher among patients with a higher risk score and undergoing procedures with greater intrathoracic dissection. This tool may be useful in identifying patients who are at risk of POAF when undergoing major thoracic surgery and may, therefore, benefit from targeted prophylactic therapy.

Prophylaxis for patients at Risk to Eliminate Post-operative Atrial Fibrillation (PREP-AF trial): a protocol for a feasibility randomized controlled study

Background

Postoperative atrial fibrillation (POAF) is a frequent adverse event after thoracic surgery with associated morbidity, mortality, and healthcare costs. It has been shown to be preventable with prophylactic amiodarone, which is only recommended in high-risk individuals due to the potential associated side effects. Risk factors for POAF have been identified and incorporated into a prediction model to identify high-risk patients. Further evaluation in the form of a multicenter clinical trial is required to assess the effectiveness of prophylaxis specifically in this high-risk population. The feasibility of such a trial first needs to be assessed.

Methods

The PREP-AF trial is a double-blind randomized controlled feasibility trial. Individuals undergoing major thoracic surgery who are identified to be high-risk by the POAF prediction model will be randomized 1:1 to receive a short course of amiodarone vs. placebo in the immediate postoperative period. The primary outcome is feasibility, which will be measured by the number of eligible patients identified, consented, and randomized; intervention adherence; and measurement of future outcomes of a full trial.

Discussion

This study will determine the feasibility of a randomized controlled trial to assess the effectiveness of prophylactic amiodarone, in high-risk patients undergoing major thoracic surgery. This will inform the development of a multi-center trial to establish if prophylactic amiodarone is safe and effective at reducing the incidence of POAF. Preventing this adverse event will not only improve outcomes for patients but also reduce the associated health resource utilization and costs.

Trial registration

ClinicalTrials.gov NCT04392921. Registered on 19 May 2020.

Early Warning of Infection in Patients Undergoing Hematopoietic Stem Cell Transplantation Using Heart Rate Variability and Serum Biomarkers

Early warning of infection is critical to reduce the risk of deterioration and mortality, especially in neutropenic patients following hematopoietic stem cell transplantation (HCT). Given that heart rate variability (HRV) is a sensitive and early marker for infection, and that serum inflammatory biomarkers can have high specificity for infection, we hypothesized their combination may be useful for accurate early warning of infection. In this study, we developed and evaluated a composite predictive model using continuous HRV with daily serum biomarker measurements to provide risk stratification of future deterioration in HCT recipients. A total of 116 ambulatory outpatients about to undergo HCT consented to collection of prospective demographic, clinical (daily vital signs), HRV (continuous electrocardiography [ECG] monitoring, laboratory [daily serum samples frozen at -80 °C]), and infection outcome variables (defined as the time of escalation of antibiotics), all from 24 hours pre-HCT to the onset of infection or 14 days post-HCT. Indications for antibiotic escalation were adjudicated as "true infection" or not by 2 blinded HCT clinicians. A composite time series of 8 HRV metrics was created for each patient, and the probability of deterioration within the next 72 hours was estimated using logistic regression modeling of composite HRV and serum biomarkers using a rule-based naïve Bayes model if the HRV-based probability exceeded a median threshold. Thirty-five patients (30%) withdrew within <24 hours owing to intolerability of ECG monitoring, leaving 81 patients, of whom 48 (59%) had antibiotic escalation adjudicated as true infection. The combined HRV and biomarker (TNF-α, IL-6, and IL-7) predictive model began increasing at ∼48 hours on average before the diagnosis of infection, could distinguish between high risk of impending infection (>90% incidence of subsequent infection within 72 hours), average risk (∼50%), and low risk (<10%), with an area under the receiver operating characteristic curve of 0.87. However, given that prophylactic predictive ECG monitoring and daily serum collection proved challenging for many patients, further refinement in measurement is necessary for further study.

Can Early Warning Systems Enhance Detection of High Risk Patients by Rapid Response Teams?

PURPOSE

We sought to evaluate if incorporating an early warning system (EWS), the Visensia Safety Index (VSI) and the National Early Warning Systems 2 (NEWS2), may lead to earlier identification of rapid response team (RRT) patients.

METHODS

This was a retrospective study (2015-2018) of patients experiencing RRT activation within a tertiary care network. We evaluated the proportion of patients with an EWS alert prior to RRT activation and their associated outcomes (primary: hospital mortality).

RESULTS

There were 6,346 RRT activations over the study period. Of these, 2042 (50.8%) patients would have had a VSI alert prior to RRT activation, with a median advanced time of 3.6 (IQR 0.5-12.8) hours, compared to 2351 (58.4%) patients and 9.8 (IQR 2.0-18.7) hours for NEWS2. Patients with a potential alert prior to RRT activation had an increased odds of mortality for both VSI (OR 1.2, 95%CI 1.1-1.3) and NEWS2 (OR 2.7, 95% CI 2.4-3.1). Prognostic accuracy for hospital mortality was similar between groups.

CONCLUSION

Utilization of an EWS by an RRT has potential to provide earlier recognition of deterioration and mortality risk among hospitalized inpatients.

Interventions to prevent anastomotic leak after esophageal surgery: a systematic review and meta-analysis

Background

Anastomotic leakage (AL) is a common and serious complication following esophagectomy. We aimed to provide an up-to-date review and critical appraisal of the efficacy and safety of all previous interventions aiming to reduce AL risk.

Methods

We searched MEDLINE and Embase from 1946 to January 2019 for randomized controlled trials (RCTs) evaluating interventions to minimize esophagogastric AL. Pooled risk ratios (RR) for AL were obtained using a random effects model.

Results

Two reviewers screened 441 abstracts and identified 17 RCTs eligible for inclusion; 11 studies were meta-analyzed. Omentoplasty significantly reduced the risk of AL by 78% [RR: 0.22; 95% CI: 0.10, 0.50] compared to conventional anastomosis (3 studies, n = 611 patients). Early removal of NG tube significantly reduced the risk of AL by 62% [RR: 0.38; 95% CI: 0.02, 0.65] compared to prolonged NG tube removal (2 studies, n = 293 patients); Stapled anastomosis did not significantly reduce the risk of AL [RR: 0.92; 95% CI: 0.45, 1.87] compared to hand-sewn anastomosis (6 studies, n = 1454 patients). The quality of evidence was high for omentoplasty (vs. conventional anastomosis), moderate for early NG tube removal (vs. prolonged NG tube removal), and very low for stapled anastomosis (vs. hand-sewn anastomosis).

Conclusions

This is the first meta-analysis to summarize the graded quality of evidence for all RCT interventions designed to reduce the risk of AL following esophagectomy. Our findings demonstrated that omentoplasty significantly reduced the risk of AL with a high quality of evidence. Although early NG tube removal significantly reduced AL risk, there is a need for further research to strengthen the quality of evidence for this finding. Evidence profiles presented in our review may help inform the development of future clinical practice recommendations.

Systematic review registration: CRD42019127181.

Endobronchial Ultrasound Staging of Operable Non-small Cell Lung Cancer: Do Triple-Normal Lymph Nodes Require Routine Biopsy?

BACKGROUND

Staging guidelines for lung cancer recommend endobronchial ultrasound (EBUS) and systematic biopsy of at least three mediastinal lymph node (LN) stations for accurate staging. A four-point ultrasonographic score (Canada Lymph Node Score [CLNS]) was developed to determine the probability of malignancy in each LN. A LN with a CLNS of < 2 is considered low probability for malignancy. We hypothesized that, in patients with cN0 non-small cell lung cancer, LNs with CLNS of < 2 may not require routine biopsy because they represent true node-negative disease.

RESEARCH QUESTION

Do LNs considered triple normal on CT scanning, PET scanning, and CLNS evaluation require routine biopsy?

STUDY DESIGN AND METHODS

LNs were evaluated for ultrasonographic features at the time of EBUS and the CLNS was applied. Triple-normal LNs were defined as cN0 on CT scanning (short axis, < 1 cm), PET scanning (no hypermetabolic activity), and EBUS (CLNS, < 2). Specificity and negative predictive value (NPV) were calculated against the gold standard pathologic diagnosis from surgically excised specimens.

RESULTS

In total, 143 LNs from 57 cN0 patients were assessed. Triple-normal LNs showed a specificity and NPV of 60% (95% CI, 51.2%-68.3%) and 93.1% (95% CI, 85.6%-97.4%), respectively. After pathologic assessment, only 5.6% (n = 8/143) of triple-normal nodes were proven to be malignant.

INTERPRETATION

At the time of staging for lung cancer, combining CT scanning, PET scanning, and CLNS criteria can identify triple-normal LNs that have a high NPV for malignancy. This raises the question of whether triple-normal LNs require routine sampling during EBUS and transbronchial needle aspiration. A prospective trial is required to confirm these findings.

Variation in management of post-operative atrial fibrillation (POAF) after thoracic surgery

OBJECTIVES

New-onset post-operative atrial fibrillation (POAF) is a frequent adverse event following major thoracic surgery and is associated with increased risk of perioperative morbidity, length of stay and stroke. It is managed initially with rate and rhythm control therapy; however, optimal duration and the need for anticoagulation are poorly understood. This study aims to assess practice variation regarding POAF management and duration.

METHODS

This retrospective, single-center cohort study included patients who underwent major thoracic surgery and developed POAF between 2008 and 2017, managed with rate and rhythm control therapy alone. Demographic, clinical, and surgical variables/outcomes, POAF management, and incidence of POAF recurrence in the 30-day post-operative period were collected. Chi-square and T-tests determined significance.

RESULTS

Of 2054 patients undergoing thoracic surgery, 155 (75%) patients developed POAF. Different rate and rhythm control agents were used, most commonly metoprolol. 107 (69%) continued rate and rhythm control therapy upon hospital discharge for a mean of 56 days. Among the 48 patients with discontinuation of rate and rhythm control therapy on discharge, none demonstrated recurrence of POAF; in contrast to 3 of 107 patients who continued on therapy. Among patients with CHA₂DS₂-VASc score ≥ 2, 15% were prescribed anticoagulation on discharge.

CONCLUSIONS

Use of rate and rhythm control therapy and anticoagulation for POAF is significantly varied in practice. Many patients are not continued on rate and rhythm control after hospital discharge, which does not appear to impact risk of POAF recurrence. Further research to inform guidelines for POAF management, including therapy duration and indications for anticoagulation is warranted.

Predictors of mortality and cost among surgical patients requiring rapid response team activation

Background

Prior studies of rapid response team (RRT) implementation for surgical patients have demonstrated mixed results with respect to reductions in poor outcomes. The aim of this study was to identify predictors of in-hospital mortality and hospital costs among surgical inpatients requiring RRT activation.

Methods

We analyzed data prospectively collected from May 2012 to May 2016 at The Ottawa Hospital. We included patients who were at least 18 years of age, who were admitted to hospital, who received either preoperative or postoperative care, and and who required RRT activation. We created a multivariable logistic regression model to describe mortality predictors and a multivariable generalized linear model to describe cost predictors.

Results

We included 1507 patients. The in-hospital mortality rate was 15.9%. The patient-related factors most strongly associated with mortality included an Elixhauser Comorbidity Index score of 20 or higher (odds ratio [OR] 3.60, 95% confidence interval [CI] 1.96-6.60) and care designations excluding admission to the intensive care unit and cardiopulmonary resuscitation (OR 3.52, 95% CI 2.25-5.52). The strongest surgical predictors included neurosurgical admission (OR 2.09, 95% CI 1.17-3.75), emergent surgery (OR 2.04, 95% CI 1.37-3.03) and occurrence of 2 or more operations (OR 1.73, 95% CI 1.21-2.46). Among RRT factors, occurrence of 2 or more RRT assessments (OR 2.01, 95% CI 1.44-2.80) conferred the highest mortality. Increased cost was strongly associated with admitting service, multiple surgeries, multiple RRT assessments and medical comorbidity.

Conclusion

RRT activation among surgical inpatients identifies a population at high risk of death. We identified several predictors of mortality and cost, which represent opportunities for future quality improvement and patient safety initiatives.

Optimal VAsopressor TitraTION in patients 65 years and older (OVATION-65): protocol and statistical analysis plan for a randomised clinical trial

INTRODUCTION

Vasodilatory hypotension is common among intensive care unit (ICU) patients; vasopressors are considered standard of care. However, optimal mean arterial pressure (MAP) targets for vasopressor titration are unknown. The objective of the Optimal VAsopressor TitraTION in patients 65 years and older (OVATION-65) trial is to ascertain the effect of permissive hypotension (vasopressor titration to achieve MAP 60-65 mm Hg) versus usual care on biomarkers of organ injury in hypotensive patients aged ≥65 years.

METHODS AND ANALYSIS

OVATION-65 is an allocation-concealed randomised trial in 7 Canadian hospitals. Eligible patients are ≥65 years of age, in an ICU with vasodilatory hypotension, receiving vasopressors for ≤12 hours to maintain MAP ≥65 mm Hg during or after adequate fluid resuscitation, and expected to receive vasopressors for ≥6 additional hours. Patients are excluded for any of the following: active treatment for spinal cord or acute brain injury; vasopressors given solely for bleeding, ventricular failure or postcardiopulmonary bypass vasoplegia; withdrawal of life-sustaining treatments expected within 48 hours; death perceived as imminent; previous enrolment in OVATION-65; organ transplant within the last year; receiving extracorporeal life support or lack of physician equipoise. Patients are randomised to permissive hypotension versus usual care for up to 28 days. The primary outcome is high-sensitivity troponin T, a biomarker of cardiac injury, on day 3. Secondary outcomes include biomarkers of injury to other organs (brain, liver, intestine, skeletal muscle); lactate (a biomarker of global tissue dysoxia); resource utilisation; adverse events; mortality (90 days and 6 months) and cognitive function (6 months). Assessors of biomarkers, mortality and cognitive function are blinded to allocation.

ETHICS AND DISSEMINATION

This protocol has been approved at all sites. Consent is obtained from the eligible patient, the substitute decision-maker if the patient is incapable, or in a deferred fashion where permitted. End-of-grant dissemination plans include presentations, publications and social media platforms and discussion forums.

TRIAL REGISTRATION NUMBER

NCT03431181.

Optimizing Our Patients' Entropy Production as Therapy? Hypotheses Originating from the Physics of Physiology

Understanding how nature drives entropy production offers novel insights regarding patient care. Whilst energy is always preserved and energy gradients irreversibly dissipate (thus producing entropy), increasing evidence suggests that they do so in the most optimal means possible. For living complex non-equilibrium systems to create a healthy internal emergent order, they must continuously produce entropy over time. The Maximum Entropy Production Principle (MEPP) highlights nature's drive for non-equilibrium systems to augment their entropy production if possible. This physical drive is hypothesized to be responsible for the spontaneous formation of fractal structures in space (e.g., multi-scale self-similar tree-like vascular structures that optimize delivery to and clearance from an organ system) and time (e.g., complex heart and respiratory rate variability); both are ubiquitous and essential for physiology and health. Second, human entropy production, measured by heat production divided by temperature, is hypothesized to relate to both metabolism and consciousness, dissipating oxidative energy gradients and reducing information into meaning and memory, respectively. Third, both MEPP and natural selection are hypothesized to drive enhanced functioning and adaptability, selecting states with robust basilar entropy production, as well as the capacity to enhance entropy production in response to exercise, heat stress, and illness. Finally, a targeted focus on optimizing our patients' entropy production has the potential to improve health and clinical outcomes. With the implications of developing a novel understanding of health, illness, and treatment strategies, further exploration of this uncharted ground will offer value.

Lung-Protective Ventilation and Associated Outcomes and Costs Among Patients Receiving Invasive Mechanical Ventilation in the ED

BACKGROUND

Invasive mechanical ventilation is often initiated in the ED, and mechanically ventilated patients may be kept in the ED for hours before ICU transfer. Although lung-protective ventilation is beneficial, particularly in ARDS, it remains uncertain how often lung-protective tidal volumes are used in the ED, and whether lung-protective ventilation in this setting impacts patient outcomes.

RESEARCH QUESTION

What is the association between the use of lung-protective ventilation in the ED and outcomes among invasively ventilated patients?

STUDY DESIGN AND METHODS

A retrospective analysis (2011-2017) of a prospective registry from eight EDs enrolling consecutive adult patients (≥ 18 years) who received invasive mechanical ventilation in the ED was performed. Lung-protective ventilation was defined by use of tidal volumes ≤ 8 mL/kg predicted body weight. The primary outcome was hospital mortality. Secondary outcomes included development of ARDS, hospital length of stay, and total hospital costs.

RESULTS

The study included 4,174 patients, of whom 2,437 (58.4%) received lung-protective ventilation in the ED. Use of lung-protective ventilation was associated with decreased odds of hospital death (adjusted OR [aOR], 0.91; 95% CI, 0.84-0.96) and development of ARDS (aOR, 0.87; 95% CI, 0.81-0.92). Patients who received lung-protective ventilation in the ED had shorter median duration of mechanical ventilation (4 vs 5 days; P < 0.01), shorter median hospital length of stay (11 vs 14 days; P < .001), and reduced total hospital costs (Can$44,348 vs Can$52,484 [US$34,153 vs US$40,418]; P = .03) compared with patients who received higher tidal volumes.

INTERPRETATION

Use of lung-protective ventilation in the ED was associated with important patient- and system-centered outcomes, including lower hospital mortality, decreased incidence of ARDS, lower hospital length of stay, and decreased total costs. Protocol development promoting the regular use of lung-protective ventilation in the ED may be of value.

Long-term Symptom Control After Laparoscopic Heller Myotomy and Dor Fundoplication for Achalasia

BACKGROUND

Achalasia is a primary esophageal motility disorder in which there is incomplete relaxation of the lower esophageal sphincter and absence of peristalsis in the lower two thirds of the esophagus. A favored treatment is laparoscopic modified Heller myotomy with Dor fundoplication (LHMDor) with more than 90% immediate beneficial effect. The short-term outcomes of LHMDor are well documented, but stability and durability of postoperative symptom control over time is less understood.

METHODS

Between 2004 and 2016, 54 patients with achalasia underwent LHMDor (single center). Using validated questionnaires, patients rated their symptoms in five domains: pain, gastroesophageal reflux disease (GERD), dysphagia, regurgitation, and quality of life. Symptom ratings were done preoperatively, 4 weeks postoperatively, 6 months postoperatively, and yearly after the operation.

RESULTS

As expected, patients reported marked improvement in dysphagia, odynophagia, regurgitation, GERD, and quality of life after the operation (P < .001). From then on, the symptom control remained durable with respect to absence of pain, regurgitation, and odynophagia; however, we observed a recurrence of GERD symptoms beginning 3 to 5 years postoperatively (P = .001 and P = .04, respectively), with associated increased antireflux medication use. After initial LHMDor, 5 patients required endoscopic dilatation an average of 1.5 years postoperatively, and no patient required reoperation. Patients reported preserved improved quality of life to 11 years after the operation (P = .001).

CONCLUSIONS

These results demonstrate the durability of LHMDor in the definitive management of achalasia, offering consistent symptomatic relief and significant improvement in quality of life over the decade after surgery, despite some increase in GERD symptoms and antireflux medication use.

Fluid Loss during Exercise-Heat Stress Reduces Cardiac Vagal Autonomic Modulation

PURPOSE

Sweat-induced fluid loss during prolonged exercise-heat stress can compromise cardiovascular and thermoregulatory function, although its effects on cardiac autonomic modulation remain unclear. We therefore examined heart rate variability (HRV) and recovery (HRRec), as surrogates of cardiac autonomic modulation, during and after prolonged exercise in the heat with and without fluid replacement.

METHODS

Eleven young and healthy men performed 90 min of semi-recumbent cycling in dry heat (40°C; 20% relative humidity) at a fixed rate of metabolic heat production (600 W; ~46% V˙O2peak) followed by 40-min resting recovery without fluid replacement (No-FR; ~3.4% reduction in body mass). On a separate day, participants completed the same protocol with fluid replacement (FR; 500-700 mL timed boluses) to offset sweat losses. Esophageal temperature and ECG were recorded throughout, with measurements analyzed over 10-min averaged epochs during baseline, each 30-min interval during exercise and 20-min interval during recovery.

RESULTS

Esophageal temperature and heart rate were elevated in No-FR relative to FR throughout exercise (all P ≤ 0.02). The HRV indices reflecting vagal influence of heart rate including the cardiac vagal index (CVI = log10[16 × SD1 × SD2]) and root-mean-square of successive differences were attenuated throughout exercise relative to baseline in both conditions (all P < 0.05), with the magnitude of the reduction greater in the No-FR condition (all P < 0.05). Further, sample entropy was reduced throughout all time points measured during exercise in the No-FR relative to FR condition (all P ≤ 0.03).

CONCLUSIONS

Our unique observations indicate that while prolonged exercise heat stress attenuates the vagal influence and complexity of cardiac rhythms, that reduction is further exacerbated by fluid loss, highlighting the importance of fluid replacement in such conditions.

Heart rate variability in older workers during work under the Threshold Limit Values for heat exposure

BACKGROUND

The Threshold Limit Values (TLV) of the American Conference of Governmental and Industrial Hygienists indicate the levels of heat stress that all workers may be repeatedly exposed to without adverse health effects. In this study, we evaluated heart rate variability (HRV) during moderate-to-heavy work performed continuously or according to different TLV work-rest (WR) allocations in healthy physically active older workers.

METHODS

Nine healthy older (58 ± 5 years) males performed three different 120-minute conditions in accordance with TLV guidelines for moderate-to-heavy intensity work (360 W fixed rate of heat production) in different wet-bulb globe temperatures (WBGT): continuous cycling at 28°C WBGT (CON), as well as intermitted work performed at WR of 3:1 in 29°C WBGT (WR3:1), and at WR of 1:1 at 30°C (WR1:1). Rectal temperature and HRV (3-lead electrocardiogram [ECG]) were assessed throughout.

RESULTS

Coefficient of Variation, Poincaré SD2, and Shannon Entropy were decreased during the CON compared with the WR3:1 when core temperature exceeded 38°C and after 1 hour of continuous work (P < .05). Also, 4 of the 12 HRV indices studied were reduced at CON compared with WR1:1 after 2 hours of accumulated work time (P < .05). Participants worked longer before core temperature reached 38°C during the WR1:1 and the WR3:1, compared with CON (P < .05).

CONCLUSIONS

Incorporating breaks during moderate-to-heavy work in the heat for older adults can reduce autonomic stress and prolong the work performed at safe core temperature levels. The TLV WR1:1 provides increased cardiac protection for older workers, as compared with the CON and the WR3:1.

Cardiac autonomic modulation in type 1 diabetes during exercise-heat stress

AIMS

Cardiac autonomic modulation, as assessed by heart rate variability (HRV), is independently attenuated by both type 1 diabetes (T1D) and exercise-heat stress, although their combined effects remain unclear. We therefore assessed HRV during exercise-heat stress in young individuals (18-37 years) with (n = 14) and without type 1 diabetes (n = 14).

METHODS

Participants completed 30-min seated rest and three, 30-min bouts of semi-recumbent cycling at light, moderate, and vigorous metabolic heat productions (200, 250, 300 W/m², respectively), each followed by 30-min recovery. Body core temperature (T_core) and electrocardiogram were recorded throughout and analyzed during the final 5-min of rest and each exercise period.

RESULTS

Relative to baseline, T_core was increased in both groups, albeit to a greater extent in type 1 diabetes during vigorous exercise (T1D, 1.1 ± 0.3 °C; control, 0.8 ± 0.3 °C; P < 0.05). Overall HRV (as reflected by entropy) was attenuated throughout exercise relative to baseline in both groups, with the magnitude of the reduction greater in type 1 diabetes during vigorous exercise (T1D, - 108%; control, - 70%; P < 0.05).

CONCLUSIONS

Given the negative correlations between decreased HRV and cardiac risk, our novel observations indicate that vigorous exercise in hot environments may pose a health concern for individuals with type 1 diabetes.

Toll-like receptors: exploring their potential connection with post-operative infectious complications and cancer recurrence

Cancer is the leading cause of death in North America. Despite modern advances in cancer therapy, many patients will ultimately develop cancer metastasis resulting in mortality. Surgery to resect early stage solid malignancies remains the cornerstone of cancer treatment. However, surgery places patients at risk of developing post-operative infectious complications that are linked to earlier cancer metastatic recurrence and cancer mortality. Toll-like receptors (TLRs) are evolutionarily-conserved sentinel receptors of the innate immune system that are activated by microbial products present during infection, leading to activation of innate immunity. Numerous types of solid cancer cells also express TLRs, with their activation augmenting their ability to metastasize. Similarly, healthy host-tissue TLRs activated during infection induce a prometastatic environment in the host. Cancer cells additionally secrete TLR activating ligands that activate both cancer TLRs and host TLRs to promote metastasis. Consequently, TLRs are an attractive therapeutic candidate to target infection-induced cancer metastasis and progression.

Age differences in cardiac autonomic regulation during intermittent exercise in the heat

PURPOSE

This study aimed to detect potential differences in heart-rate variability (HRV) during a moderate-intensity intermittent exercise in the heat among physically active young (25.8 ± 1.9 years), middle-aged (43.5 ± 2.8 years), and older (62.9 ± 3.7 years) men.

METHODS

Thirty-three participants (11/group) performed four successive bouts of 15-min cycling at a moderate fixed rate of metabolic heat production of ~ 400 W; each separated by a 15-min recovery with 1 h of final recovery in a hot and dry environment (35 °C, 20% relative humidity). Twelve HRV indices were computed that have been commonly described in the literature, and characterized various domains of the variability and complexity of heart rate.

RESULTS

Cardiac autonomic regulation during intermittent exercise in the heat, as well as during pre-exercise rest and recovery was significantly affected by age, as changes were observed among the three different aged groups in five indices (p ≤ 0.05). Similarly, time influenced cardiac autonomic regulation as three indices showed changes across time (p ≤ 0.05) during intermittent exercise, whilst five indices displayed significant changes (p ≤ 0.05) during rest and recovery in the heat.

CONCLUSIONS

This study supports that moderate-intensity intermittent exercise in the heat is associated with significant cardiac autonomic dysregulation in older men, as compared to young and middle-aged men, yet it highlights the importance of developing preventative health strategies for heat-related illness in aged individuals.

Age-related reductions in heart rate variability do not worsen during exposure to humid compared to dry heat: A secondary analysis

We conducted a secondary analysis to investigate whether age-related attenuations in heart rate variability (HRV) worsen during exposure to moderate, dry (36.5°C, 20% RH) or humid (36.5°C, 60% RH) heat conditions that resulted in greater body heat storage among older compared to young participants, and during humid compared to dry heat, regardless of age. Six HRV indices [heart rate (HR), coefficient of variation (CoV), detrended fluctuation analysis: α1, low frequency power, high frequency power, and low/high frequency ratio] were assessed in 10 young (21 ± 3 y) and 9 older (65 ± 5 y) adults for 15-min prior to (baseline), and at the end of a 120-min exposure to dry and humid heat while seated at rest. Our results demonstrated a condition (dry and humid) x time (baseline and end) interaction effect on HR (p = 0.047) such that HR gradually increased during humid heat exposure yet remained similar during dry heat exposure across groups. We also found an age-related attenuation in CoV at baseline for both the dry (young: 0.097 ± 0.023%; older: 0.054 ± 0.016%) and humid (young: 0.093 ± 0.034%; older: 0.056 ± 0.014%) heat conditions (p < 0.02). Those age-related attenuations in CoV, however, were not magnified throughout the exposure nor different between conditions (p > 0.05). While older adults stored more heat during a brief 120-min exposure to dry heat compared to their young counterparts, this was not paralleled by further age-related impairments in HRV even when body heat storage and cardiovascular strain were exacerbated by exposure to humid heat.

Frequency of Screening and SBT Technique Trial - North American Weaning Collaboration (FAST-NAWC): a protocol for a multicenter, factorial randomized trial

RATIONALE

In critically ill patients receiving invasive mechanical ventilation (MV), research supports the use of daily screening to identify patients who are ready to undergo a spontaneous breathing trial (SBT) followed by conduct of an SBT. However, once daily (OD) screening is poorly aligned with the continuous care provided in most intensive care units (ICUs) and the best SBT technique for clinicians to use remains controversial.

OBJECTIVES

To identify the optimal screening frequency and SBT technique to wean critically ill adults in the ICU.

METHODS

We aim to conduct a multicenter, factorial design randomized controlled trial with concealed allocation, comparing the effect of both screening frequency (once versus at least twice daily [ALTD]) and SBT technique (Pressure Support [PS] + Positive End-Expiratory Pressure [PEEP] vs T-piece) on the time to successful extubation (primary outcome) in 760 critically ill adults who are invasively ventilated for at least 24 h in 20 North American ICUs. In the OD arm, respiratory therapists (RTs) will screen study patients between 06:00 and 08:00 h. In the ALTD arm, patients will be screened at least twice daily between 06:00 and 08:00 h and between 13:00 and 15:00 h with additional screens permitted at the clinician's discretion. When the SBT screen is passed, an SBT will be conducted using the assigned technique (PS + PEEP or T-piece). We will follow patients until successful extubation, death, ICU discharge, or until day 60 after randomization. We will contact patients or their surrogates six months after randomization to assess health-related quality of life and functional status.

RELEVANCE

The around-the-clock availability of RTs in North American ICUs presents an important opportunity to identify the optimal SBT screening frequency and SBT technique to minimize patients' exposure to invasive ventilation and ventilator-related complications.

TRIAL REGISTRATION

Clinical Trials.gov, NCT02399267 . Registered on Nov 21, 2016 first registered.

Frailty and invasive mechanical ventilation: association with outcomes, extubation failure, and tracheostomy

PURPOSE

Invasive mechanical ventilation is a common form of life support provided to critically ill patients. Frailty is an emerging prognostic factor for poor outcome in the Intensive Care Unit (ICU); however, its association with adverse outcomes following invasive mechanical ventilation is unknown. We sought to evaluate the association between frailty, defined by the Clinical Frailty Scale (CFS), and outcomes of ICU patients receiving invasive mechanical ventilation.

METHODS

We performed a retrospective analysis (2011-2016) of a prospectively collected registry from two hospitals of consecutive ICU patients ≥ 18 years of age receiving invasive mechanical ventilation. CFS scores were based on recorded pre-admission function at the time of hospital admission. The primary outcome was hospital mortality. Secondary outcomes included discharge to long-term care, extubation failure at time of first liberation attempt, and tracheostomy.

RESULTS

We included 8110 patients, and 2529 (31.2%) had frailty (CFS ≥ 5). Frailty was associated with increased odds of hospital death (adjusted odds ratio [aOR]: 1.24 [95% confidence interval [CI] 1.10-1.40) and discharge to long-term care (aOR 1.21 [95% CI 1.13-1.35]). As compared to patients without frailty, patients with frailty had increased odds of extubation failure (aOR 1.17 [95% CI 1.04-1.37]), hospital death following extubation failure (aOR 1.18 [95% CI 1.07-1.28]), tracheostomy (aOR 1.17 [95% CI 1.01-1.36]), and hospital death following tracheostomy (aOR 1.14 [95% CI 1.03-1.25]).

CONCLUSIONS

The presence of frailty among patients receiving mechanical ventilation is associated with increased odds of hospital mortality, discharge to long-term care, extubation failure, and need for tracheostomy.

Project management lessons learned from the multicentre CYCLE pilot randomized controlled trial

Background

Clinical trials management can be studied using project management theory. The CYCLE pilot randomized controlled trial (RCT) was conducted to determine the feasibility of a future rehabilitation trial of early in-bed cycling in the intensive care unit (ICU). In-bed cycling is a novel intervention, not typically available in ICUs. Implementation of this intervention requires personnel with specialized clinical expertise caring for critically ill patients and use of the in-bed cycle. Our objective was to describe the implementation and conduct of our pilot RCT using a project management approach.

Methods

We retrospectively reviewed activities, timelines, and personnel involved in the trial. We organized activities into four project management phases: initiation, planning, execution, and monitoring and controlling. Data sources included Methods Centre documents used for trial coordination and conduct, and the trial data set. We report descriptive statistics as counts and proportions and also medians and quartiles, and we summarize the lessons learned.

Results

Seven ICUs in Canada participated in the trial. Time from research ethics board and contracts submission to first enrolment was a median (first quartile, third quartile) of 185 (146, 209) and 162 (114, 181) days, respectively. We trained 128 personnel on the CYCLE pilot RCT protocol, and 80 (63%) completed trial-related activities. Four sites required additional training after start-up due to staff turnover and leaves of absence. Over 15 months, we screened 864 patients: 256 were eligible and 66 were enrolled. Despite an 85% consent rate, 74% (190/256) of eligible patients were not randomized, largely (80% [152/190]) due to physiotherapist availability. Thirteen percent of recruitment weeks were lost due to physiotherapist staffing shortages. We highlight five key lessons learned: (1) prepare and anticipate site needs; (2) communicate regularly; (3) proactively analyse and act on process measure data; (4) develop contingency plans; (5) express appreciation to participating sites.

Conclusions

Our analysis highlights the scope of relevant activities, rigorous training and monitoring, number and types of required personnel, and time required to conduct a multicentre ICU rehabilitation intervention trial. Our lessons learned can help others interested in implementing complex intervention trials, such as rehabilitation.

Trial registration

ClinicalTrials.gov, NCT02377830. Registered prospectively on 4 March 2015.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3634-7) contains supplementary material, which is available to authorized users.

Outcomes of hospitalized hematologic oncology patients receiving rapid response system activation for acute deterioration

BACKGROUND

Patients with hematologic malignancies who are admitted to hospital are at increased risk of deterioration and death. Rapid response systems (RRSs) respond to hospitalized patients who clinically deteriorate. We sought to describe the characteristics and outcomes of hematologic oncology inpatients requiring rapid response system (RRS) activation, and to determine the prognostic accuracy of the SIRS and qSOFA criteria for in-hospital mortality of hematologic oncology patients with suspected infection.

METHODS

We used registry data from two hospitals within The Ottawa Hospital network, between 2012 and 2016. Consecutive hematologic oncology inpatients who experienced activation of the RRS were included in the study. Data was gathered at the time of RRS activation and assessment. The primary outcome was in-hospital mortality. Logistical regression was used to evaluate for predictors of in-hospital mortality.

RESULTS

We included 401 patients during the study period. In-hospital mortality for all included patients was 41.9% (168 patients), and 145 patients (45%) were admitted to ICU following RRS activation. Among patients with suspected infection at the time of RRS activation, Systemic Inflammatory Response Syndrome (SIRS) criteria had a sensitivity of 86.9% (95% CI 80.9-91.6) and a specificity of 38.2% (95% CI 31.9-44.8) for predicting in-hospital mortality, while Quick Sequential Organ Failure Assessment (qSOFA) criteria had a sensitivity of 61.9% (95% CI 54.1-69.3) and a specificity of 91.4% (95% CI 87.1-94.7). Factors associated with increased in-hospital mortality included transfer to ICU after RRS activation (adjusted odds ratio [OR] 3.56, 95% CI 2.12-5.97) and a higher number of RRS activations (OR 2.45, 95% CI 1.63-3.69). Factors associated with improved survival included active malignancy treatment at the time of RRS activation (OR 0.54, 95% CI 0.34-0.86) and longer hospital length of stay (OR 0.78, 95% CI 0.70-0.87).

CONCLUSIONS

Hematologic oncology inpatients requiring RRS activation have high rates of subsequent ICU admission and mortality. ICU admission and higher number of RRS activations are associated with increased risk of death, while active cancer treatment and longer hospital stay are associated with lower risk of mortality. Clinicians should consider these factors in risk-stratifying these patients during RRS assessment.