Resident work hours: why keeping the status quo may not be such a bad thing

Resident duty hours have become an increasingly debated topic in post-graduate medical education. Work-hour restrictions have been implemented for first-year residents in the US and more recently for all residents in Quebec. Current and future work-hour rules affect a variety of stakeholders: government, hospitals, residency training programs, patients, and most of all residents. In this article, we hope to examine the issue from a Canadian perspective and delineate some of the reasons why changing the current call structure may have potentially deleterious effects to all those concerned

Neurocognitive impairment across the continuum of critical illness: exploration of acute insults, functional risk factors, and clinical monitoring tools.

Critically ill patients of all ages suffer from high burden of neurocognitive impairment during (i.e. delirium) and following (i.e. long term cognitive impairment) critical illness that is associated with worse patient and healthy system outcomes. Ischemia has emerged as a plausible mechanism given the high prevalence of hypotension and shock, ischemic injury on neuroimaging, and impairment of cerebral autoregulation in these patients. However, the burden of ischemic insults during critical illness and mechanisms responsible for these insults are poorly described. Furthermore, while baseline impairment in cerebrovascular function can render patients more vulnerable to ischemia, such baseline functional assessments in patients with high risk of critical illness have not been considered. Finally, the operational limitations of existing cognitive batteries preclude routine linkage of ischemic insults and baseline impairment in cerebrovascular function with neurocognitive outcomes. In this work we carried out three studies to address these knowledge gaps. In the first study, we showed that critically ill patients with respiratory failure or shock experience deviations in cerebral blood flow velocity consistent with ischemia or hyperemia for 17-24% of the observation time. These deviations occurred irrespective of the state of cerebral autoregulation and were not explained by concurrent changes in blood pressure or CO2. These deviations represent a plausible ischemic insult that may explain high prevalence of ischemic injury in previous neuroimaging and histopathologic studies, and warrants further research to understand the underlying mechanism and link with neurocognitive outcomes. In the second study, we showed that hemodialysis patients have baseline impairment in cerebrovascular function prior to onset of critical illness, which may render them more vulnerable to ischemic injury during critical illness as a result of perturbation in cerebral blood flow shown in our first study. In our third study, we optimized an existing comprehensive web-based cognitive battery for monitoring cognitive outcomes in ICU patients, which should enable future linkage of ischemic insults and baseline impairment in cerebrovascular function from our first two studies with neurocognitive outcomes, as well enable routine clinical monitoring of cognitive recovery in ICU survivors

Evidence-Based Considerations for the Design of an Open-Source Ventilator: A Systematic Review

OBJECTIVE: To inform the design of open-source ventilators, we performed a systematic review of clinical practice guidelines (CPGs) to consolidate the evidence on mechanical ventilation strategies that result in improved patient-important outcomes for acute hypoxic respiratory failure. DATA SOURCES: We developed a search strategy to identify relevant CPGs from Ovid Medline, Ovid Medline In-Process & Other Non-Indexed Citations, Embase, the Cochrane Library, Mendeley, and Google scholar from 2010 to February 17, 2022. STUDY SELECTION: Using a two-step screening process with two independent reviewers, we included CPGs that made recommendations on mechanical ventilation strategies of interest. Guidelines that reported at least one recommendation about mechanical ventilation in ICU patients with acute hypoxic respiratory failure were included. DATA EXTRACTION: From the 13 eligible guidelines, we collected data on country, aim, patient population, impact on morbidity and mortality (effect size and CIs), recommendations, strength of Recommendation (as per Grading of Recommendations, Assessment, Development and Evaluations), and details of supporting evidence base. DATA SYNTHESIS: We identified three ventilation strategies that confer a mortality and morbidity benefit for ventilated patients with acute hypoxic respiratory failure: low-tidal volume ventilation, plateau pressures of less than 30 cm H2O, and higher positive end-expiratory pressure (PEEP). These moderate-to-strong recommendations were based on moderate-to-high certainty in evidence. We identified several other recommendations with no or minimal certainty in evidence. CONCLUSIONS: Our systematic review of international CPGs identified no recommendations favoring specific mode of ventilation and three ventilation strategies that confer mortality and morbidity benefits, backed by moderate-to-strong evidence. Ventilator design teams must include the ability to consistently provide and measure low-tidal volume ventilation, plateau pressures of less than 30 cm H2O, and higher PEEP into their designs. Based on our findings, we provide the first public framework for open-source ventilator design

Ethics of non-Therapeutic research on imminently dying patients in the intensive care unit

Non-Therapeutic research with imminently dying patients in intensive care presents complex ethical issues. The vulnerabilities of the imminently dying, together with societal disquiet around death and dying, contribute to an intuition that such research is beyond the legitimate scope of scientific inquiry. Yet excluding imminently dying patients from research hinders the advancement of medical science to the detriment of future patients. Building on existing ethical guidelines for research, we propose a framework for the ethical design and conduct of research involving the imminently dying. To enable rapid translation to practice, we frame the approach in the form of eight ethical questions that researchers and research ethics committees ought to answer prior to conducting any research with this patient population. (1) Does the study hypothesis require the inclusion of imminently dying patients? (2) Are non-Therapeutic risks and burdens minimised consistent with sound scientific design? (3) Are the risks of these procedures no more than minimal risk? (4) Are these non-Therapeutic risks justified insofar as they are reasonable in relation to the anticipated benefits of the study? (5) Will valid informed consent be obtained from an authorised surrogate decision maker? (6) How will incidental findings be handled? (7) What additional steps are in place to protect families and significant others of research participants? (8) What additional steps are in place to protect clinical staff and researchers? Several ethical challenges hinder research with imminently dying patients. Nonetheless, provided adequate protections are in place, non-Therapeutic research with imminently dying patients is ethically justifiable. Applying our framework to an ongoing study, we demonstrate how our question-driven approach is well suited to guiding investigators and research ethics committees

Effect of sedation with inhaled anaesthetics on cognitive and psychiatric outcomes in critically ill adults: a systematic review protocol

Introduction The COVID-19 pandemic has renewed interest in the use of inhaled anaesthetics for sedation of ventilated critically ill patients. Preliminary data show that inhaled anaesthetics reduce lung inflammation, time to extubation and intensive care unit length of stay compared with intravenous sedatives. However, the impact of inhaled anaesthetics on cognitive and psychiatric outcomes is not well described in this setting. Randomised controlled trials are underway to establish if inhaled anaesthetics affect these and other patient and health system outcomes. Our aim is to summarise the known effects of inhaled sedatives on cognitive and psychiatric outcomes. Methods and analysis In this systematic review, we will use MEDLINE, EMBASE, and PsycINFO to identify studies from 1970 to 2021 that assessed cognitive and psychiatric outcomes in critically ill adult patients sedated with inhaled anaesthetics. We will include case series, observational and cohort studies and randomised controlled trials. We will exclude case studies due to the heterogeneity of reporting in these studies. For randomised controlled trials comparing inhaled to intravenous sedation, we will report cognitive and psychiatric outcomes for both study arms. Studies will be selected based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Data will be extracted using a standardised data extraction tool by two independent reviewers. Studies will be assessed for bias using the Cochrane risk of bias tool for randomised controlled trials, or the Newcastle-Ottawa Scale for cohort and case-control studies. Findings will be reported according to outcome and descriptive statistics will be used to illustrate findings in a narrative fashion. Ethics and dissemination The systematic review uses published data and therefore does not require ethics approval. Results will be disseminated via publication in peer-reviewed journals and presentation at conferences related to the field. PROSPERO registration number CRD42021236455

Non-Invasive Monitoring of Core Body Temperature for Targeted Temperature Management in Post-Cardiac Arrest Care

Importance: Accurate monitoring of core body temperature is integral to targeted temperature management (TTM) following cardiac arrest. However, there are no reliable non-invasive methods for monitoring temperature during TTM. Objectives: We compared the accuracy and precision of a novel non-invasive Zero-Heat-Flux Thermometer (SpotOn™) to a standard invasive esophageal probe in a cohort of patients undergoing TTM post-cardiac arrest. Design, Setting, and Participants: We prospectively enrolled 20 patients undergoing post-cardiac arrest care in the intensive care units at the London Health Sciences Centre in London, Canada. A SpotOn™ probe was applied on each patient\u27s forehead, while an esophageal temperature probe was inserted, and both temperature readings were recorded at 1-min intervals for the duration of TTM. Main outcomes and Measures: We compared the SpotOn™ and esophageal monitors using the Bland–Altman analysis and the Pearson correlation, with accuracy set as a primary outcome. Secondary outcomes included precision and correlation. Bias exceeding 0.1°C and limits of agreement exceeding 0.5°C were considered clinically important. Results: Sixteen (80%) of patients had complete data used in the final analysis. The median (interquartile range) duration of recording was 38 (12–56) h. Compared to the esophageal probe, SpotOn™ had a bias of 0.06 ± 0.45°C and 95% limits of agreement of −0.83 to 0.95°C. The Pearson correlation coefficient was 0.97 (95% confidence interval 0.9663–0.9678), with a two-tailed p \u3c 0.0001. Conclusion and Relevance: The SpotOn™ is an accurate method that may enable non-invasive monitoring of core body temperature during TTM, although its precision is slightly worse than the predefined 0.5°C when compared to invasive esophageal probe

CEPP: Canadian Extracorporeal Life Support (ECLS) Protocol Project

Background: Extracorporeal life support (ECLS) is associated with high morbidity and mortality. Complications and mortality are higher at lower-volume centres. Most Canadian ECLS institutions are low-volume centres. Protocols offer one way to share best practices among institutions to improve outcomes. Whether Canadian centres have ECLS protocols, and whether these protocols are comprehensive and homogenous across centres, is unknown. Methods: Purposeful sampling with mixed methods was used. A Delphi panel defined key elements relevant to the ECLS process. Documentation used in the delivery of ECLS services was requested from programs. Institutional protocols were assessed using deductive coding to determine the presence of key elements. Results: A total of 37 key elements spanning 5 domains (referral, initiation, maintenance, termination, and administration) were identified. Documentation from 13 institutions across 10 provinces was obtained. Institutions with heart or lung transplantation programs had more-complete documentation than did non-transplantation programs. Only 5 key elements were present in at least 50% of protocols (anticoagulation strategy, ventilation strategy, defined referral process, selection criteria, weaning process), and variation was seen in how institutions approached each of these elements. Conclusions: The completeness of ECLS protocols varies across Canada. Programs describe variable approaches to key elements. This variability might represent a lack of evidence or consensus in these areas and creates the opportunity for collaboration among institutions to share protocols and best practice. The key-element framework provides a common language that programs can use to develop ECLS programs, initiate quality-improvement projects, and identify research agendas

Proteinase 3 contributes to endothelial dysfunction in an experimental model of sepsis

In sepsis-induced inflammation, polymorphonuclear neutrophils (PMNs) contribute to vascular dysfunction. The serine proteases proteinase 3 (PR3) and human leukocyte elastase (HLE) are abundant in PMNs and are released upon degranulation. While HLE’s role in inflammation-induced endothelial dysfunction is well studied, PR3’s role is largely uninvestigated. We hypothesized that PR3, similarly to HLE, contributes to vascular barrier dysfunction in sepsis. Plasma PR3 and HLE concentrations and their leukocyte mRNA levels were measured by ELISA and qPCR, respectively, in sepsis patients and controls. Exogenous PR3 or HLE was applied to human umbilical vein endothelial cells (HUVECs) and HUVEC dysfunction was assessed by FITC-dextran permeability and electrical resistance. Both PR3 and HLE protein and mRNA levels were significantly increased in sepsis patients (P \u3c 0.0001 and P \u3c 0.05, respectively). Additionally, each enzyme independently increased HUVEC monolayer FITC-dextran permeability (P \u3c 0.01), and decreased electrical resistance in a time- and dose-dependent manner (P \u3c 0.001), an effect that could be ameliorated by novel treatment with carbon monoxide-releasing molecule 3 (CORM-3). The serine protease PR3, in addition to HLE, lead to vascular dysfunction and increased endothelial permeability, a hallmark pathological consequence of sepsis-induced inflammation. CORMs may offer a new strategy to reduce serine protease-induced vascular dysfunction

Effects of Systemic Physiology on Mapping Resting-State Networks Using Functional Near-Infrared Spectroscopy

Resting-state functional connectivity (rsFC) has gained popularity mainly due to its simplicity and potential for providing insights into various brain disorders. In this vein, functional near-infrared spectroscopy (fNIRS) is an attractive choice due to its portability, flexibility, and low cost, allowing for bedside imaging of brain function. While promising, fNIRS suffers from non-neural signal contaminations (i.e., systemic physiological noise), which can increase correlation across fNIRS channels, leading to spurious rsFC networks. In the present work, we hypothesized that additional measurements with short channels, heart rate, mean arterial pressure, and end-tidal CO2 could provide a better understanding of the effects of systemic physiology on fNIRS-based resting-state networks. To test our hypothesis, we acquired 12 min of resting-state data from 10 healthy participants. Unlike previous studies, we investigated the efficacy of different pre-processing approaches in extracting resting-state networks. Our results are in agreement with previous studies and reinforce the fact that systemic physiology can overestimate rsFC. We expanded on previous work by showing that removal of systemic physiology decreases intra- and inter-subject variability, increasing the ability to detect neural changes in rsFC across groups and over longitudinal studies. Our results show that by removing systemic physiology, fNIRS can reproduce resting-state networks often reported with functional magnetic resonance imaging (fMRI). Finally, the present work details the effects of systemic physiology and outlines how to remove (or at least ameliorate) their contributions to fNIRS signals acquired at rest