Brian W. Roberts

Association Between Postresuscitation Partial Pressure of Arterial Carbon Dioxide and Neurological Outcome in Patients With Post–Cardiac Arrest Syndrome

Background— Partial pressure of arterial CO2 (PaCO2) is a regulator of cerebral blood flow after brain injury. Recent guidelines for the management of cardiac arrest recommend maintaining PaCO2 at 40 to 45 mm Hg after successful resuscitation; however, there is a paucity of data on the prevalence of PaCO2 derangements during the post–cardiac arrest period and its association with outcome. Methods and Results— We analyzed a prospectively compiled and maintained cardiac arrest registry at a single academic medical center. Inclusion criteria are as follows: age ≥18, nontrauma arrest, and comatose after return of spontaneous circulation. We analyzed arterial blood gas data during 0 to 24 hours after the return of spontaneous circulation and determined whether patients had exposure to hypocapnia and hypercapnia (defined as PaCO2 ⩽30 mm Hg and PaCO2 ≥50 mm Hg, respectively, based on previous literature). The primary outcome was poor neurological function at hospital discharge, defined as Cerebral Performance Category ≥3. We used multivariable logistic regression, with multiple sensitivity analyses, adjusted for factors known to predict poor outcome, to determine whether post–return of spontaneous circulation hypocapnia and hypercapnia were independent predictors of poor neurological function. Of 193 patients, 52 (27%) had hypocapnia only, 63 (33%) had hypercapnia only, 18 (9%) had both hypocapnia and hypercapnia exposure, and 60 (31%) had no exposure; 74% of patients had poor neurological outcome. Hypocapnia and hypercapnia were independently associated with poor neurological function, odds ratio 2.43 (95% confidence interval, 1.04–5.65) and 2.20 (95% confidence interval, 1.03–4.71), respectively. Conclusions— Hypocapnia and hypercapnia were common after cardiac arrest and were independently associated with poor neurological outcome. These data suggest that PaCO2 derangements could be potentially harmful for patients after resuscitation from cardiac arrest.

Long-term survival of critically ill patients treated with prolonged mechanical ventilation: a systematic review and meta-analysis

BACKGROUND Prolonged dependence on mechanical ventilation after critical illness is an emerging public health challenge; however, long-term outcomes are incompletely understood. We aimed to systematically analyse long-term survival of critically ill patients treated with prolonged mechanical ventilation. METHODS We searched PubMed, CINAHL, and the Cochrane Library between 1988 and Nov 6, 2013, with no language restrictions, for studies on prolonged mechanical ventilation. We included studies of adult populations treated with mechanical ventilation for more than 14 days, who were admitted to a ventilator weaning unit, or who had a tracheostomy for acute respiratory failure. We abstracted data with a standardised collection template and assessed study quality (ie, risk of bias) using a customised Newcastle-Ottawa Scale. We did a stratified analysis based on study setting (eg, acute vs post-acute care hospitals), and used a random-effects model to calculate pooled statistics (proportions with 95% CIs) for all outcomes. We did sensitivity analyses based on study quality (ie, high-quality studies only) and country of origin (USA vs non-USA and USA vs UK). The primary outcome was mortality at 1 year. Secondary outcomes were in-hospital mortality, discharge destination among survivors, successful liberation from mechanical ventilation while in hospital, and mortality at timepoints longer than 1 year. FINDINGS Of 6326 studies identified, 402 underwent full manuscript review, and 124 studies from 16 countries met the inclusion criteria. 39 studies reported mortality at 1 year, which was 59% (95% CI 56-62). Among the 29 high-quality studies, the pooled mortality at 1 year was 62% (95% CI 57-67). Pooled mortality at hospital discharge was 29% (95% CI 26-32). However, only 19% (16-24) were discharged to home and only 50% (47-53) were successfully liberated from mechanical ventilation. For studies in post-acute care hospitals, outcomes were worse in the USA than internationally (mortality at 1 year was 73% [95% CI 67-78] in the USA vs 47% [29-65] in non-USA countries; in-hospital mortality was 31% [26-37] vs 18% [14-24]; and liberation from ventilation was 47% [42-51] vs 63% [59-68]; p<0·0001 for all). INTERPRETATION Although a high proportion of patients survived to hospital discharge, fewer than half of patients survived beyond 1 year. Future studies should focus on optimum patient selection for prolonged mechanical ventilation and integration of long-term outcome information into clinical decision making. FUNDING Cooper University Health Care and Cooper Medical School of Rowan University.

Association between initial prescribed minute ventilation and post-resuscitation partial pressure of arterial carbon dioxide in patients with post-cardiac arrest syndrome

AbstractBackgroundPost-cardiac arrest hypocapnia/hypercapnia have been associated with poor neurological outcome. However, the impact of arterial carbon dioxide (CO2) derangements during the immediate post-resuscitation period following cardiac arrest remains uncertain. We sought to test the correlation between prescribed minute ventilation and post-resuscitation partial pressure of CO2 (PaCO2), and to test the association between early PaCO2 and neurological outcome.MethodsWe retrospectively analyzed a prospectively compiled single-center cardiac arrest registry. We included adult (age ≥ 18 years) patients who experienced a non-traumatic cardiac arrest and required mechanical ventilation. We analyzed initial post-resuscitation ventilator settings and initial arterial blood gas analysis (ABG) after initiation of post-resuscitation ventilator settings. We calculated prescribed minute ventilation: MVmL/kg/min=tidalvolumeTV/idealbodyweightIBWxrespiratoryrateRR for each patient. We then used Pearson’s correlation to test the correlations between prescribed MV and PaCO2. We also determined whether patients had normocapnia (PaCO2 between 30 and 50 mmHg) on initial ABG and tested the association between normocapnia and good neurological function (Cerebral Performance Category 1 or 2) at hospital discharge using logistic regression analyses.ResultsSeventy-five patients were included. The majority of patients were in-hospital arrests (85%). Pulseless electrical activity/asystole was the initial rhythm in 75% of patients. The median (IQR) TV, RR, and MV were 7 (7 to 8) mL/kg, 14 (14 to 16) breaths/minute, and 106 (91 to 125) mL/kg/min, respectively. Hypocapnia, normocapnia, and hypercapnia were found in 15%, 62%, and 23% of patients, respectively. Good neurological function occurred in 32% of all patients, and 18%, 43%, and 12% of patients with hypocapnia, normocapnia, and hypercapnia respectively. We found prescribed MV had only a weak correlation with initial PaCO2, R = -0.40 (P < 0.001). Normocapnia was associated with good neurological function, odds ratio 4.44 (95% CI 1.33 to 14.85).ConclusionsWe found initial prescribed MV had only a weak correlation with subsequent PaCO2 and that early Normocapnia was associated with good neurological outcome. These data provide rationale for future research to determine the impact of PaCO2 management during mechanical ventilation in post-cardiac arrest patients.

Association between chest compression rates and clinical outcomes following in-hospital cardiac arrest at an academic tertiary hospital

AIMS Recent guidelines for management of cardiac arrest recommend chest compression rates of 100-120 compressions/min. However, animal studies have found cardiac output to increase with rates up to 150 compressions/min. The objective of this study was to test the association between chest compression rates during cardiopulmonary resuscitation for in-hospital cardiac arrest (IHCA) and outcome. METHODS We conducted a prospective observational study at a single academic medical center. INCLUSION CRITERIA age≥18, IHCA, cardiopulmonary resuscitation performed. We analyzed chest compression rates measured by defibrillation electrodes, which recorded changes in thoracic impedance. The primary outcome was return of spontaneous circulation (ROSC). We used multivariable logistic regression to determine odds ratios for ROSC by chest compression rate categories (100-120, 121-140, >140 compressions/min), adjusted for chest compression fraction (proportion of time chest compressions provided) and other known predictors of outcome. We set 100-120 compressions/min as the reference category for the multivariable model. RESULTS We enrolled 222 consecutive patients and found a mean chest compression rate of 139±15. Overall 53% achieved ROSC; among 100-120, 121-140, and >140 compressions/min, ROSC was 29%, 64%, and 49% respectively. A chest compression rate of 121-140 compressions/min had the greatest likelihood of ROSC, odds ratio 4.48 (95% CI 1.42-14.14). CONCLUSIONS In this sample of adult IHCA patients, a chest compression rate of 121-140 compressions/min had the highest odds ratio of ROSC. Rates above the currently recommended 100-120 compressions/min may improve the chances of ROSC among IHCA patients.

Effects of hypercapnia in sepsis: protocol for a systematic review of clinical and preclinical data

BackgroundRespiratory failure requiring mechanical ventilation is a common manifestation of end-organ damage among patients with sepsis and has a high morbidity and mortality rate, as well as substantial associated treatment costs. Considering the burden of this condition, there is great need to identify novel, pragmatic therapies to improve outcomes in this population. Hypercapnia has shown benefits in several different ex vivo and in vivo models of lung injury. However, it is currently unclear if hypercapnia can confer clinical benefit among patients with sepsis. The objective of this systematic review is to collate the biomedical literature of preclinical and clinical studies testing the effects of higher PaCO2 levels in the setting of sepsis.MethodsWe will perform a qualitative systematic review of preclinical and clinical studies evaluating the effects of hypercapnia in sepsis. We will search CENTRAL, PubMed, CINAHL, and EMBASE using a comprehensive strategy. We will screen the reference lists of the articles we select for inclusion to identify additional studies for potential inclusion. Two independent reviewers will review all search results. Upon inclusion of articles, we will extract data using a standardized form. We will use tables to describe the study type, population included, exposure and control groups, outcome measures, and effects of exposure on outcome measures compared to controls.DiscussionThis systematic review aims to synthesize the world’s literature on the effects of hypercapnia in the setting of sepsis. We expect this systematic review will find that majority of the studies will demonstrate a potential benefit of higher PaCO2 levels in sepsis. The results of this systematic review will contribute to the understanding of the effects of hypercapnia in the setting of sepsis and promote future research of PaCO2 management in mechanically ventilated patients with sepsis.Systematic review registrationThe systematic review is registered in the PROSPERO international prospective register of systematic review (PROSPERO # CRD42018086703).

Compassionomics: Hypothesis and Experimental Approach

Recent reports indicate that healthcare is experiencing a compassion crisis - an absence of (or inconsistency in) compassionate patient care. It is currently unclear if, or to what extent, this exerts significant effects on health and healthcare. Experimental data are few, and this represents a critical knowledge gap for all health sciences. We hypothesize that compassionate care is beneficial for patients (better outcomes), healthcare systems and payers (lower costs), and healthcare providers (lower burnout). Compassionomics is the branch of knowledge and scientific study of the effects of compassionate healthcare, and herein we describe a framework for hypothesis testing. If the hypotheses are confirmed, compassionate healthcare can be established in the domain of evidence-based medicine.

Early interventions for the prevention of post-traumatic stress symptoms in survivors of critical illness: protocol for a systematic review

Introduction Post-traumatic stress disorder (PTSD) is being increasingly reported among survivors of critical illness and injury. Previous work has demonstrated that PTSD reduces patient quality of life and ability to return to work, as well as increases healthcare costs. As such, identifying interventions aimed at preventing the development of critical illness-related PTSD could have an important public health impact. The objective of this systematic review is to collate the world’s literature on early interventions aimed at preventing PTSD among survivors of critical illness. Methods and analysis We will perform a qualitative systematic review of human clinical trials of interventions aimed at preventing or reducing critical illness-related PTSD symptoms. We will methodically search CENTRAL, MEDLINE, Embase and CINAHL. We will also search websites containing details on clinical trials registration (National Library of Medicine’s ClinicalTrials.gov and the WHO’s International Clinical Trials Registry Platform), as well as screen reference lists of the articles we select for inclusion to identify additional studies for potential inclusion. Two authors will independently review all search results. After identification and inclusion of articles, we will use a standardised form for data extraction. We will use tables to describe the study type, populations, interventions tested and timing of interventions, outcome measures and effects of interventions on outcome measures compared with control groups. This review will be completed between 1 August 2017 and 31 August 2017. Ethics and dissemination The proposed systematic review will not collect individual patient level data and does not require ethical approval. Results of this study will contribute to the understanding of critical illness-related PTSD and help prompt future research aimed at further developing interventions to prevent PTSD symptoms in survivors of critical illness. PROSPERO registration number This systematic review is registered in the PROSPERO international prospective register of systematic reviews (registration number CRD42017069672).

Response to Letter Regarding Article, “Association Between Postresuscitation Partial Pressure of Arterial Carbon Dioxide and Neurological Outcome in Patients With Post–Cardiac Arrest Syndrome”

We would like to thank Dr Eastwood and colleagues for their interest in our recent article.1 In their letter, they raise concern that our results may reflect local practice and therefore should be interpreted with some caution. Our study was a single-center prospective study. We agree that a study of larger scope or of a different population could have found different results and that further research is needed to determine the optimal Paco2 range during the initial post–cardiac arrest period. However, our finding that hypercapnia in the post–cardiac arrest period is associated with poor neurological outcome is consistent with previous findings of other brain-injured patients such as pediatric post–cardiac arrest and traumatic brain injury patients.2,3 We are familiar with Dr Eastwood and colleagues’ …