Jeffrey M. Singh

Critically Ill Patients With 2009 Influenza A(H1N1) Infection in Canada

CONTEXT Between March and July 2009, the largest number of confirmed cases of 2009 influenza A(H1N1) infection occurred in North America. OBJECTIVE To describe characteristics, treatment, and outcomes of critically ill patients in Canada with 2009 influenza A(H1N1) infection. DESIGN, SETTING, AND PATIENTS A prospective observational study of 168 critically ill patients with 2009 influenza A(H1N1) infection in 38 adult and pediatric intensive care units (ICUs) in Canada between April 16 and August 12, 2009. MAIN OUTCOME MEASURES The primary outcome measures were 28-day and 90-day mortality. Secondary outcomes included frequency and duration of mechanical ventilation and duration of ICU stay. RESULTS Critical illness occurred in 215 patients with confirmed (n = 162), probable (n = 6), or suspected (n = 47) community-acquired 2009 influenza A(H1N1) infection. Among the 168 patients with confirmed or probable 2009 influenza A(H1N1), the mean (SD) age was 32.3 (21.4) years; 113 were female (67.3%) and 50 were children (29.8%). Overall mortality among critically ill patients at 28 days was 14.3% (95% confidence interval, 9.5%-20.7%). There were 43 patients who were aboriginal Canadians (25.6%). The median time from symptom onset to hospital admission was 4 days (interquartile range [IQR], 2-7 days) and from hospitalization to ICU admission was 1 day (IQR, 0-2 days). Shock and nonpulmonary acute organ dysfunction was common (Sequential Organ Failure Assessment mean [SD] score of 6.8 [3.6] on day 1). Neuraminidase inhibitors were administered to 152 patients (90.5%). All patients were severely hypoxemic (mean [SD] ratio of Pao(2) to fraction of inspired oxygen [Fio(2)] of 147 [128] mm Hg) at ICU admission. Mechanical ventilation was received by 136 patients (81.0%). The median duration of ventilation was 12 days (IQR, 6-20 days) and ICU stay was 12 days (IQR, 5-20 days). Lung rescue therapies included neuromuscular blockade (28% of patients), inhaled nitric oxide (13.7%), high-frequency oscillatory ventilation (11.9%), extracorporeal membrane oxygenation (4.2%), and prone positioning ventilation (3.0%). Overall mortality among critically ill patients at 90 days was 17.3% (95% confidence interval, 12.0%-24.0%; n = 29). CONCLUSION Critical illness due to 2009 influenza A(H1N1) in Canada occurred rapidly after hospital admission, often in young adults, and was associated with severe hypoxemia, multisystem organ failure, a requirement for prolonged mechanical ventilation, and the frequent use of rescue therapies.

Evolution of Diaphragm Thickness during Mechanical Ventilation. Impact of Inspiratory Effort

RATIONALE Diaphragm atrophy and dysfunction have been reported in humans during mechanical ventilation, but the prevalence, causes, and functional impact of changes in diaphragm thickness during routine mechanical ventilation for critically ill patients are unknown. OBJECTIVES To describe the evolution of diaphragm thickness over time during mechanical ventilation, its impact on diaphragm function, and the influence of inspiratory effort on this phenomenon. METHODS In three academic intensive care units, 107 patients were enrolled shortly after initiating ventilation along with 10 nonventilated intensive care unit patients (control subjects). Diaphragm thickness and contractile activity (quantified by the inspiratory thickening fraction) were measured daily by ultrasound. MEASUREMENTS AND MAIN RESULTS Over the first week of ventilation, diaphragm thickness decreased by more than 10% in 47 (44%), was unchanged in 47 (44%), and increased by more than 10% in 13 (12%). Thickness did not vary over time following extubation or in nonventilated patients. Low diaphragm contractile activity was associated with rapid decreases in diaphragm thickness, whereas high contractile activity was associated with increases in diaphragm thickness (P = 0.002). Contractile activity decreased with increasing ventilator driving pressure (P = 0.01) and controlled ventilator modes (P = 0.02). Maximal thickening fraction (a measure of diaphragm function) was lower in patients with decreased or increased diaphragm thickness (n = 10) compared with patients with unchanged thickness (n = 10; P = 0.05 for comparison). CONCLUSIONS Changes in diaphragm thickness are common during mechanical ventilation and may be associated with diaphragmatic weakness. Titrating ventilatory support to maintain normal levels of inspiratory effort may prevent changes in diaphragm configuration associated with mechanical ventilation.

Incidence and predictors of critical events during urgent air–medical transport

Background: Little is known about the risks of urgent air–medical transport used in regionalized health care systems. We sought to determine the incidence of intransit critical events and identify factors associated with these events. Methods: We conducted a population-based, retrospective cohort study using clinical and administrative data. We included all adults undergoing urgent air–medical transport in the Canadian province of Ontario between Jan. 1, 2004, and May 31, 2006. The primary outcome was in-transit critical events, which we defined as death, major resuscitative procedure, hemodynamic deterioration, or inadvertent extubation or respiratory arrest. Results: We identified 19 228 patients who underwent air–medical transport during the study period. In-transit critical events were observed in 5.1% of all transports, for a rate of 1 event per 12.6 hours of transit time. Events consisted primarily of new hypotension or airway management procedures. Independent predictors of critical events included female sex (adjusted odds ratio [OR] 1.3, 95% confidence interval [CI] 1.1–1.5), assisted ventilation before transport (adjusted OR 3.0, 95% CI 2.3–3.7), hemodynamic instability before transport (adjusted OR 3.2, 95% CI 2.5–4.1), transport in a fixed-wing aircraft (adjusted OR 1.5, 95% CI 1.2–1.8), increased duration of transport (adjusted OR 1.02 per 10-minute increment, 95% CI 1.01–1.03), on-scene calls (adjusted OR 1.7, 95% CI 1.4–2.1) and type of crew (adjusted OR 0.6 for advanced care paramedics v. critical care paramedics, 95% CI 0.5–0.7). Interpretation: Critical events occurred in about 1 in every 20 air–medical transports and were associated with multiple risk factors at the patient, transport and system levels. These findings have implications for the refinement of training of paramedic transport crews and processes for triage and transport.

The Insertion and Management of External Ventricular Drains: An Evidence-Based Consensus Statement : A Statement for Healthcare Professionals from the Neurocritical Care Society.

Abstract External ventricular drains (EVDs) are commonly placed to monitor intracranial pressure and manage acute hydrocephalus in patients with a variety of intracranial pathologies. The indications for EVD insertion and their efficacy in the management of these various conditions have been previously addressed in guidelines published by the Brain Trauma Foundation, American Heart Association and combined committees of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons. While it is well recognized that placement of an EVD may be a lifesaving intervention, the benefits can be offset by procedural and catheter-related complications, such as hemorrhage along the catheter tract, catheter malposition, and CSF infection. Despite their widespread use, there are a lack of high-quality data regarding the best methods for placement and management of EVDs to minimize these risks. Existing recommendations are frequently based on observational data from a single center and may be biased to the authors’ view. To address the need for a comprehensive set of evidence-based guidelines for EVD management, the Neurocritical Care Society organized a committee of experts in the fields of neurosurgery, neurology, neuroinfectious disease, critical care, pharmacotherapy, and nursing. The Committee generated clinical questions relevant to EVD placement and management. They developed recommendations based on a thorough literature review using the Grading of Recommendations Assessment, Development, and Evaluation system, with emphasis placed not only on the quality of the evidence, but also on the balance of benefits versus risks, patient values and preferences, and resource considerations.

Pro/con debate: Do the benefits of regionalized critical care delivery outweigh the risks of interfacility patient transport?

You are providing input in planning for critical care services to a large regional health authority. You are considering concentrating some critical care services into high-volume regional centres of excellence, as has been done in other fields of medicine. In your region, this would require several centres with differing levels of expertise that are geographically separated. Given there are inherent risks and time delays associated with interfacility patient transport, you debate whether these potential risks outweigh the benefits of regional centres of excellence.

Critical Events During Land-Based Interfacility Transport

STUDY OBJECTIVE The risks associated with urgent land-based transport of critically ill patients are not well known and have important implications for patient safety, care delivery, and policy development. We seek to determine the incidence of in-transit critical events and associated patient- and transport-level factors. METHODS We conducted a retrospective cohort study using clinical and administrative data. We included adults undergoing urgent land-based critical care transport by a dedicated transport provider between January 1, 2005, and December 31, 2010. The primary outcome was in-transit critical event, defined by adverse events or resuscitative procedures. RESULTS In-transit critical events were observed in 333 (6.5%) of 5,144 urgent land transports. New hypotension (4.4%) or new vasopressors (1.6%) were the most common critical events, with fewer respiratory events (1.3%). Advanced care paramedics had a higher rate compared with critical care paramedics (odds ratio [OR] 1.6; 95% confidence interval [CI] 1.1 to 2.2), especially for patients with baseline hemodynamic instability. In multivariate analysis, mechanical ventilation (adjusted OR 1.7; 95% CI 1.3 to 2.2), baseline hemodynamic instability (adjusted OR 3.7; 95% CI 2.8 to 4.9), out-of-hospital duration (adjusted OR 3.6; 95% CI 2.9 to 4.5 per log-fold increase in time), and neurologic diagnosis (adjusted OR 0.5; 95% CI 0.3 to 0.7 compared with that of medical patients) were associated with critical events. CONCLUSION Critical events occurred in approximately 1 in 15 transports and were associated with mechanical ventilation, hemodynamic instability, and transport duration, and were less frequent in neurologic patients. The finding that hypotension is common and predicted by pretransport hemodynamic instability has implications for the preparation and management of this patient group.

Ventilation Practices and Critical Events during Transport of Ventilated Patients outside of Hospital: A Retrospective Cohort Study

Abstrast Introduction. Little is known about mechanical ventilation practices during patient transport outside of hospital in the civilian setting, although these practices may have clinical impact. Objective. We set out to describe ventilation practice, the use of lung-protective ventilation strategies, administration of sedation and neuromuscular blockade, and related critical events during out-of-hospital transport of ventilated patients. Methods. We conducted a population-based retrospective cohort study. Ventilator, pharmacy, and clinical data were extracted from the database of the provincial transport medicine agency in Ontario, Canada. Patients at risk for acute lung injury were identified by explicit screening criteria and lung-protective ventilation was assessed according to evidence-based thresholds. Critical events occurring during transport consisting of clinical deterioration or resuscitative procedures were recorded. Results. We identified 1,735 mechanically ventilated adults who received out-of-hospital transport. Volume control and pressure control were the most commonly used ventilation modes. The median tidal volume delivered during transport was 500 mL (interquartile range 450–600) with positive end-expiratory pressure (PEEP) of 5 cmH2O (5–7) and peak inspiratory pressure of 24 cmH2O (20–29). Most patients (92%) were ventilated with peak pressures ≤ 35 cmH2O; 22% of patients were ventilated with PEEP < 5 cmH2O. Ventilation in patients at risk of acute lung injury was not significantly different, and 68% of this subgroup was ventilated within lung-protective thresholds. Sedation was administered in 1,235 transports (71.2%) with frequent repeat administration. Neuromuscular blockade was administered in 385 transports (22.2%). Critical events occurred during 297 (17.1%) transports, due primarily to new-onset hypotension (n = 208). New in-transit hypotension was independently associated with sedative administration. Conclusions. In-transit mechanical ventilation practices are variable, although patient exposure to potentially injurious pressures and volumes is uncommon. The application of PEEP is modest. In-transit hypotension is common and associated with sedative administration. The extent to which these practices impact patient outcome is unclear.

High-frequency oscillatory ventilation in adults with acute respiratory distress syndrome.

The last decade has seen increased appreciation of ventilator-induced lung injury. The understanding that the process of mechanical ventilation can itself damage lungs has spurned the search for ventilation strategies that are more lung protective. High-frequency oscillatory ventilation is a mode of high-frequency ventilation that may accomplish all of the current goals of lung protection. Historically, much of the data evaluating high-frequency oscillatory ventilation came from neonatal and pediatric populations. In the past year, a number of provocative and exciting studies have been published that contribute significantly to our understanding of high-frequency oscillatory ventilation, its role in preventing and reducing ventilator-induced lung injury, and its use in the support of adult patients with lung injury. In this article, we discuss the current understanding of high-frequency oscillatory ventilation and highlight the most recent literature addressing its application in adult patients with acute respiratory distress syndrome.

Methodology of Systematic Reviews and Recommendations

Although research in the field of spinal cord injury (SCI) is a relatively new endeavor, a remarkable number of papers focused on this subspecialty have been published in a broad variety of journals over the last two decades. A multidisciplinary group of experts, including clinical epidemiologists, neurosurgical and orthopedic spine surgeons, basic scientists, rehabilitation specialists, intensivists, and allied health professionals (nursing and physical therapy) was assembled through the Spinal Cord Injury Solutions Network to summarize the existing literature focusing on 12 key topics related to acute traumatic SCI, which have not been recently reviewed. The objective was to develop evidence-based recommendations to help translate current science into clinical practice and to identify new directions for research. For each topic one to three specific questions were formulated by consensus through the expert panel. A systematic review of the literature was performed to determine the current evidence for the specific questions. A primary literature search was performed using MEDLINE, CINAHL, EMBASE, and Cochrane databases. A secondary search strategy incorporated additional articles referenced in significant publications (i.e., meta-analysis, systematic and nonsystematic review articles). Two reviewers independently reviewed the titles and abstracts yielded by this comprehensive search and subsequently selected articles based on the predetermined inclusion and inclusion criteria. Data were extracted for population into evidentiary tables. Selected articles were rated for level of evidence and methodological quality, information that was also included in evidentiary tables. Disagreements were resolved by a third reviewer or consensus-based discussion. Based on the evidence compiled, answers to the targeted questions were formulated and recommendations generated by consensus-based discussion and anonymized voting using Delphi methodology. A level of consensus of 80% or higher was considered to represent strong agreement.

Worldwide Survey of the "Assessing Pain, Both Spontaneous Awakening and Breathing Trials, Choice of Drugs, Delirium Monitoring/Management, Early Exercise/Mobility, and Family Empowerment" (ABCDEF) Bundle.

Objectives: To assess the knowledge and use of the Assessment, prevention, and management of pain; spontaneous awakening and breathing trials; Choice of analgesia and sedation; Delirium assessment; Early mobility and exercise; and Family engagement and empowerment (ABCDEF) bundle to implement the Pain, Agitation, Delirium guidelines. Design: Worldwide online survey. Setting: Intensive care. Intervention: A cross-sectional online survey using the Delphi method was administered to intensivists worldwide, to assess the knowledge and use of all aspects of the ABCDEF bundle. Measurement and Main Results: There were 1,521 respondents from 47 countries, 57% had implemented the ABCDEF bundle, with varying degrees of compliance across continents. Most of the respondents (83%) used a scale to evaluate pain. Spontaneous awakening trials and spontaneous breathing trials are performed in 66% and 67% of the responder ICUs, respectively. Sedation scale was used in 89% of ICUs. Delirium monitoring was implemented in 70% of ICUs, but only 42% used a validated delirium tool. Likewise, early mobilization was “prescribed” by most, but 69% had no mobility team and 79% used no formal mobility scale. Only 36% of the respondents assessed ICU-acquired weakness. Family members were actively involved in 67% of ICUs; however, only 33% used dedicated staff to support families and only 35% reported that their unit was open 24 hr/d for family visits. Conclusions: The current implementation of the ABCDEF bundle varies across individual components and regions. We identified specific targets for quality improvement and adoption of the ABCDEF bundle. Our data reflect a significant but incomplete shift toward patient- and family-centered ICU care in accordance with the Pain, Agitation, Delirium guidelines.