An Update on Management of Adult Patients with Acute Respiratory Distress Syndrome: An Official American Thoracic Society Clinical Practice Guideline.

Background: This document updates previously published Clinical Practice Guidelines for the management of patients with acute respiratory distress syndrome (ARDS), incorporating new evidence addressing the use of corticosteroids, venovenous extracorporeal membrane oxygenation, neuromuscular blocking agents, and positive end-expiratory pressure (PEEP). Methods: We summarized evidence addressing four "PICO questions" (patient, intervention, comparison, and outcome). A multidisciplinary panel with expertise in ARDS used the Grading of Recommendations, Assessment, Development, and Evaluation framework to develop clinical recommendations. Results: We suggest the use of: 1) corticosteroids for patients with ARDS (conditional recommendation, moderate certainty of evidence), 2) venovenous extracorporeal membrane oxygenation in selected patients with severe ARDS (conditional recommendation, low certainty of evidence), 3) neuromuscular blockers in patients with early severe ARDS (conditional recommendation, low certainty of evidence), and 4) higher PEEP without lung recruitment maneuvers as opposed to lower PEEP in patients with moderate to severe ARDS (conditional recommendation, low to moderate certainty), and 5) we recommend against using prolonged lung recruitment maneuvers in patients with moderate to severe ARDS (strong recommendation, moderate certainty). Conclusions: We provide updated evidence-based recommendations for the management of ARDS. Individual patient and illness characteristics should be factored into clinical decision making and implementation of these recommendations while additional evidence is generated from much-needed clinical trials.

Resumption of Cardiac Activity after Withdrawal of Life-Sustaining Measures.

BACKGROUND: The minimum duration of pulselessness required before organ donation after circulatory determination of death has not been well studied. METHODS: We conducted a prospective observational study of the incidence and timing of resumption of cardiac electrical and pulsatile activity in adults who died after planned withdrawal of life-sustaining measures in 20 intensive care units in three countries. Patients were intended to be monitored for 30 minutes after determination of death. Clinicians at the bedside reported resumption of cardiac activity prospectively. Continuous blood-pressure and electrocardiographic (ECG) waveforms were recorded and reviewed retrospectively to confirm bedside observations and to determine whether there were additional instances of resumption of cardiac activity. RESULTS: A total of 1999 patients were screened, and 631 were included in the study. Clinically reported resumption of cardiac activity, respiratory movement, or both that was confirmed by waveform analysis occurred in 5 patients (1%). Retrospective analysis of ECG and blood-pressure waveforms from 480 patients identified 67 instances (14%) with resumption of cardiac activity after a period of pulselessness, including the 5 reported by bedside clinicians. The longest duration after pulselessness before resumption of cardiac activity was 4 minutes 20 seconds. The last QRS complex coincided with the last arterial pulse in 19% of the patients. CONCLUSIONS: After withdrawal of life-sustaining measures, transient resumption of at least one cycle of cardiac activity after pulselessness occurred in 14% of patients according to retrospective analysis of waveforms; only 1% of such resumptions were identified at the bedside. These events occurred within 4 minutes 20 seconds after a period of pulselessness. (Funded by the Canadian Institutes for Health Research and others.).

Do Thresholds for Invasive Ventilation in Hypoxemic Respiratory Failure Exist? A Cohort Study.

Rationale: Invasive ventilation is a significant event for patients with respiratory failure. Physiologic thresholds standardize the use of invasive ventilation in clinical trials, but it is unknown whether thresholds prompt invasive ventilation in clinical practice. Objectives: To measure, in patients with hypoxemic respiratory failure, the probability of invasive ventilation within 3 hours after meeting physiologic thresholds. Methods: We studied patients admitted to intensive care receiving FiO2 of 0.4 or more via nonrebreather mask, noninvasive positive pressure ventilation, or high-flow nasal cannula, using data from the Medical Information Mart for Intensive Care (MIMIC)-IV database (2008-2019) and the Amsterdam University Medical Centers Database (AmsterdamUMCdb) (2003-2016). We evaluated 17 thresholds, including the ratio of arterial to inspired oxygen, the ratio of saturation to inspired oxygen ratio, composite scores, and criteria from randomized trials. We report the probability of invasive ventilation within 3 hours of meeting each threshold and its association with covariates using odds ratios (ORs) and 95% credible intervals (CrIs). Measurements and Main Results: We studied 4,726 patients (3,365 from MIMIC, 1,361 from AmsterdamUMCdb). Invasive ventilation occurred in 28% (1,320). In MIMIC, the highest probability of invasive ventilation within 3 hours of meeting a threshold was 20%, after meeting prespecified neurologic or respiratory criteria while on vasopressors, and 19%, after a ratio of arterial to inspired oxygen of <80 mm Hg. In AmsterdamUMCdb, the highest probability was 34%, after vasopressor initiation, and 25%, after a ratio of saturation to inspired oxygen of <90. The probability after meeting the threshold from randomized trials was 9% (MIMIC) and 13% (AmsterdamUMCdb). In MIMIC, a race/ethnicity of Black (OR, 0.75; 95% CrI, 0.57-0.96) or Asian (OR, 0.6; 95% CrI, 0.35-0.95) compared with White was associated with decreased probability of invasive ventilation after meeting a threshold. Conclusions: The probability of invasive ventilation within 3 hours of meeting physiologic thresholds was low and associated with patient race/ethnicity.

Ketamine sedation in the intensive care unit: a survey of Canadian intensivists.

PURPOSE: We sought to understand the beliefs and practices of Canadian intensivists regarding their use of ketamine as a sedative in critically ill patients and to gauge their interest in a randomized controlled trial (RCT) examining its use in the intensive care unit (ICU). METHODS: We designed and validated an electronic self-administered survey examining the use of ketamine as a sedative infusion for ICU patients. We surveyed 400 physician members of the Canadian Critical Care Society (CCCS) via email between February and April 2022 and sent three reminders at two-week intervals. The survey was redistributed in January 2023 to improve the response rate. RESULTS: We received 87/400 (22%) completed questionnaires. Most respondents reported they rarely use ketamine as a continuous infusion for sedation or analgesia in the ICU (52/87, 58%). Physicians reported the following conditions would make them more likely to use ketamine: asthma exacerbation (73/87, 82%), tolerance to opioids (68/87, 77%), status epilepticus (44/87, 50%), and severe acute respiratory distress syndrome (33/87, 38%). Concern for side-effects that limited respondents' use of ketamine include adverse psychotropic effects (61/87, 69%) and delirium (47/87, 53%). The majority of respondents agreed there is need for an RCT to evaluate ketamine as a sedative infusion in the ICU (62/87, 71%). CONCLUSION: This survey of Canadian intensivists illustrates that use of ketamine as a continuous infusion for sedation is limited, and is at least partly driven by concerns of adverse psychotropic effects. Canadian physicians endorse the need for a trial investigating the safety and efficacy of ketamine as a sedative for critically ill patients.

RéSUMé: OBJECTIF: Nous avons cherché à comprendre les croyances et les pratiques des intensivistes pratiquant au Canada concernant leur utilisation de la kétamine comme sédatif chez la patientèle gravement malade et à évaluer leur intérêt pour une étude randomisée contrôlée (ERC) examinant son utilisation à l'unité de soins intensifs (USI). MéTHODE: Nous avons mis au point et validé un sondage électronique auto-administré examinant l'utilisation de la kétamine comme perfusion sédative pour les patient·es aux soins intensifs. Nous avons envoyé le sondage à 400 médecins membres de la Société canadienne de soins intensifs (SCCC) par courriel entre février et avril 2022 et envoyé trois rappels à intervalles de deux semaines. Le sondage a été redistribué en janvier 2023 afin d'améliorer le taux de réponse. RéSULTATS: Nous avons reçu 87 questionnaires remplis sur 400 (22 %). La plupart des personnes répondantes ont déclaré qu'elles utilisaient rarement la kétamine en perfusion continue pour la sédation ou l'analgésie à l'USI (52/87, 58 %). Les médecins ont déclaré que les conditions suivantes les rendraient plus susceptibles d'utiliser de la kétamine : une exacerbation de l'asthme (73/87, 82 %), une tolérance aux opioïdes (68/87, 77 %), un état de mal épileptique (44/87, 50 %) et un syndrome de détresse respiratoire aigu (33/87, 38 %). Les inquiétudes quant aux effets secondaires qui ont limité l'utilisation de la kétamine par les répondant·es comprennent les effets psychotropes indésirables (61/87, 69 %) et le delirium (47/87, 53 %). La majorité des personnes répondantes étaient d'accord qu'une ERC est nécessaire pour évaluer la kétamine en tant que perfusion sédative à l'USI (62/87, 71 %). CONCLUSION: Cette enquête menée auprès d'intensivistes au Canada montre que l'utilisation de la kétamine comme perfusion continue pour la sédation est limitée, au moins en partie en raison d'inquiétudes liées aux effets psychotropes indésirables. Les médecins pratiquant au Canada reconnaissent la nécessité d'une étude sur l'innocuité et l'efficacité de la kétamine comme sédatif pour la patientèle gravement malade.

The association between nutritional risk index and ICU outcomes across hematologic malignancy patients with acute respiratory failure.

Patients with hematological malignancies (HM) are at risk of acute respiratory failure (ARF). Malnutrition, a common association with HM, has the potential to influence ICU outcomes. Geriatric nutritional risk index (G-NRI) is a score derived from albumin and weight, which reflects risk of protein-energy malnutrition. We evaluated the association between G-NRI at ICU admission and ICU mortality in HM patients with ARF. We conducted a single center retrospective study of ventilated HM patients between 2014 and 2018. We calculated G-NRI for all patients using their ICU admission albumin and weight. Our primary outcome was ICU mortality. Secondary outcomes included duration of mechanical ventilation and ICU length of stay. Two hundred eighty patients were admitted to the ICU requiring ventilation. Median age was 62 years (IQR 51-68), 42% (n = 118) were females, and median SOFA score was 11 (IQR 9-14). The most common type of HM was acute leukemia (54%) and 40% underwent hematopoietic cell transplant. Median G-NRI was 87 (IQR 79-99). ICU mortality was 51% (n = 143) with a median duration of ventilation of 4 days (IQR 2-7). Mortality across those at severe malnutrition (NRI < 83.5) was 59% (65/111) compared to 46% (76/164) across those with moderate-no risk (p = 0.047). On multivariable analysis, severe NRI (OR 2.34, 95% CI 1.04-5.27, p = 0.04) was significantly associated with ICU mortality. In this single center, exploratory study, severe G-NRI was prognostic of ICU mortality in HM patients admitted with respiratory failure.

Oxygenation thresholds for invasive ventilation in hypoxemic respiratory failure: a target trial emulation in two cohorts.

BACKGROUND: The optimal thresholds for the initiation of invasive ventilation in patients with hypoxemic respiratory failure are unknown. Using the saturation-to-inspired oxygen ratio (SF), we compared lower versus higher hypoxemia severity thresholds for initiating invasive ventilation. METHODS: This target trial emulation included patients from the Medical Information Mart for Intensive Care (MIMIC-IV, 2008-2019) and the Amsterdam University Medical Centers (AmsterdamUMCdb, 2003-2016) databases admitted to intensive care and receiving inspired oxygen fraction ≥ 0.4 via non-rebreather mask, noninvasive ventilation, or high-flow nasal cannula. We compared the effect of using invasive ventilation initiation thresholds of SF < 110, < 98, and < 88 on 28-day mortality. MIMIC-IV was used for the primary analysis and AmsterdamUMCdb for the secondary analysis. We obtained posterior means and 95% credible intervals (CrI) with nonparametric Bayesian G-computation. RESULTS: We studied 3,357 patients in the primary analysis. For invasive ventilation initiation thresholds SF < 110, SF < 98, and SF < 88, the predicted 28-day probabilities of invasive ventilation were 72%, 47%, and 19%. Predicted 28-day mortality was lowest with threshold SF < 110 (22.2%, CrI 19.2 to 25.0), compared to SF < 98 (absolute risk increase 1.6%, CrI 0.6 to 2.6) or SF < 88 (absolute risk increase 3.5%, CrI 1.4 to 5.4). In the secondary analysis (1,279 patients), the predicted 28-day probability of invasive ventilation was 50% for initiation threshold SF < 110, 28% for SF < 98, and 19% for SF < 88. In contrast with the primary analysis, predicted mortality was highest with threshold SF < 110 (14.6%, CrI 7.7 to 22.3), compared to SF < 98 (absolute risk decrease 0.5%, CrI 0.0 to 0.9) or SF < 88 (absolute risk decrease 1.9%, CrI 0.9 to 2.8). CONCLUSION: Initiating invasive ventilation at lower hypoxemia severity will increase the rate of invasive ventilation, but this can either increase or decrease the expected mortality, with the direction of effect likely depending on baseline mortality risk and clinical context.

Resuscitation outcomes in patients with cancer: experience in a large urban cancer centre.

PURPOSE: Hospitalized patients with cancer who experience cardiopulmonary arrest have historically low survival rates. This retrospective cohort study describes outcomes of patients at a large Canadian cancer centre who had a "code medical emergency" activated, and the use of pragmatic criteria to identify patients with poor survival following resuscitation. METHODS: We included hospitalized patients with cancer who had a "code blue" activated between January 2007 and December 2018. Our primary outcome was intensive care unit (ICU) mortality. We developed pragmatic criteria to identify patients with "poor prognosis" for survival from cardiopulmonary resuscitation (CPR) based on disease status and candidacy for further cancer treatment. We used descriptive statistics to analyze the outcomes of poor prognosis patients. RESULTS: Two hundred and twenty-five patients had a code blue activated. The median age was 61 yr, 52% were male, and 48% had a solid tumour. Overall, 173/225 (77%) patients survived the code blue; 164 were admitted to the ICU, where 49% (81/164) died; 31% survived to hospital discharge; and 16% (n = 27) were alive at one year. One hundred and twenty out of 225 (53%) required chest compressions; spontaneous circulation returned in 61% (73/120), and 12% (14/120) survived to hospital discharge. Patients meeting "poor prognosis" criteria (114, 51%) were more likely to die in the ICU (64% vs 35%; P < 0.001) or in hospital (86% vs 59%; P < 0.001), and more often had goals-of-care discussions prior to the code blue (46% vs 7%; P < 0.001). At one year, only 2% of poor prognosis patients were alive, compared with 24% of patients who did not meet any poor prognosis criteria. CONCLUSION: Hospitalized patients with cancer requiring CPR have poor hospital and long-term outcomes. The proposed set of pragmatic criteria may be useful to identify patients unlikely to benefit from CPR and life support, to trigger early goals of care discussions, and to avoid potentially goal-discordant interventions.

RéSUMé: OBJECTIF: Les patient·es hospitalisé·es atteint·es d'un cancer qui subissent un arrêt cardiorespiratoire ont des taux de survie historiquement bas. Cette étude de cohorte rétrospective décrit les issues des patient·es d'un grand centre canadien de cancérologie pour qui un « code d'urgence médicale ¼ a été activé et l'utilisation de critères pragmatiques pour identifier les patient·es ayant une faible survie après réanimation. MéTHODE: Nous avons inclus les personnes hospitalisées atteintes d'un cancer pour qui un « code bleu ¼ avait été activé entre janvier 2007 et décembre 2018. Notre critère d'évaluation principal était la mortalité à l'unité de soins intensifs (USI). Nous avons développé des critères pragmatiques pour identifier les personnes ayant un « mauvais pronostic ¼ de survie à la réanimation cardiorespiratoire (RCR) en fonction de l'état de la maladie et de leur éligibilité à un traitement ultérieur contre le cancer. Nous avons utilisé des statistiques descriptives pour analyser les issues des patient·es ayant un mauvais pronostic. RéSULTATS: Un code bleu a été activé pour deux cent vingt-cinq patient·es. L'âge médian était de 61 ans, 52 % étaient des hommes et 48 % avaient une tumeur solide. Dans l'ensemble, 173/225 (77 %) patient·es ont survécu au code bleu; 164 ont été admis·es aux soins intensifs, où 49 % (81/164) sont décédé·es; 31 % ont survécu jusqu'à leur congé de l'hôpital; et 16 % (n = 27) étaient en vie après un an. Cent vingt sur 225 (53 %) ont nécessité des compressions thoraciques; la circulation spontanée est revenue chez 61 % (73/120), et 12 % (14/120) ont survécu jusqu'à leur congé de l'hôpital. Les patient·es répondant aux critères de « mauvais pronostic ¼ (114, 51 %) étaient plus susceptibles de mourir à l'USI (64 % vs 35 %; P < 0,001) ou à l'hôpital (86 % vs 59 %; P < 0,001) et avaient plus souvent eu des discussions sur les objectifs de soins avant l'activation du code bleu (46 % vs 7 %; P < 0,001). À un an, seulement 2 % des patient·es ayant un mauvais pronostic étaient en vie, contre 24 % des patient·es qui ne présentaient aucun critère de mauvais pronostic. CONCLUSION: Les personnes hospitalisées atteintes d'un cancer nécessitant une RCR ont de mauvaises issues intra-hospitalières et à plus long terme. L'ensemble de critères pragmatiques proposé peut être utile pour identifier la patientèle peu susceptible de bénéficier de la RCR et du maintien des fonctions vitales, pour amorcer rapidement des discussions sur les objectifs de soins et pour éviter les interventions potentiellement discordantes par rapport à ces objectifs.

Helmet noninvasive ventilation compared to facemask noninvasive ventilation and high-flow nasal cannula in acute respiratory failure: a systematic review and meta-analysis.

BACKGROUND: Although small randomised controlled trials (RCTs) and observational studies have examined helmet noninvasive ventilation (NIV), uncertainty remains regarding its role. We conducted a systematic review and meta-analysis to examine the effect of helmet NIV compared to facemask NIV or high-flow nasal cannula (HFNC) in acute respiratory failure. METHODS: We searched multiple databases to identify RCTs and observational studies reporting on at least one of mortality, intubation, intensive care unit (ICU) length of stay, NIV duration, complications or comfort with NIV therapy. We assessed study risk of bias using the Cochrane Risk of Bias 2 tool for RCTs and the Ottawa-Newcastle Scale for observational studies, and rated certainty of pooled evidence using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) framework. RESULTS: We separately pooled data from 16 RCTs (n=949) and eight observational studies (n=396). Compared to facemask NIV, based on low certainty of evidence, helmet NIV may reduce mortality (relative risk 0.56, 95% CI 0.33-0.95) and intubation (relative risk 0.35, 95% CI 0.22-0.56) in both hypoxic and hypercapnic respiratory failure, but may have no effect on duration of NIV. There was an uncertain effect of helmet NIV on ICU length of stay and development of pressure sores. Data from observational studies were consistent with the foregoing findings but of lower certainty. Based on low and very low certainty data, helmet NIV may reduce intubation compared to HFNC, but its effect on mortality is uncertain. CONCLUSIONS: Compared to facemask NIV, helmet NIV may reduce mortality and intubation; however, the effect of helmet NIV compared to HFNC remains uncertain.

Catheter management across patients with hematologic malignancies and catheter-related blood stream infections: a systematic review.

Catheter-related bloodstream infection (CRBSI) can lead to ICU admission in patients with hematologic malignancy (HM). Variability exists in the management of catheters given the need for long-term access and co-existing thrombocytopenia or coagulopathy. We conducted a systematic review to evaluate catheter management in patients with CRBSI. Literature searches were conducted up to December 20, 2021 across MEDLINE, EMBASE, CENTRAL, CINAHL, and PubMed. Observational studies and RCTs of adults (> 16) with HM were included. Our primary outcome was mortality and secondary outcomes included infection recurrence and ICU admission. We identified 23 studies (N = 2026 patients), of which 22 were observational. Across the 12 studies (N = 801) that reported on bacterial organisms, 528 (65.9%) were gram positive, and 273 (34.1%) were gram negative. Catheters were removed in 1266 (62%) and retained in 760 (38%) patients. Removal was associated with a mean 30-day mortality of 13.14% (SD 9.12; 90/685) and reinfection rate of 5.49% (SD 2.88; 22/401) compared to 39.23% (SD 14.58; 122/311) and 10.75% (SD 21.07; 10/93), respectively, if retained. Catheter retention may be associated with a higher risk of mortality and infection recurrence. Further prospective research should assess catheter management in this population, including potential harms associated with retention.

Predictors and Hospital Outcomes in Pregnant Patients Undergoing Extracorporeal Membrane Oxygenation: A Nationwide Study.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is increasingly used in patients with severe cardiorespiratory collapse. Although prior large database reviews of ECMO use in the peripartum population exist, they do not stratify by ECMO indication nor do they include obstetric conditions such as preeclampsia. Our objective was to characterize the incidence, indication-associated mortality, and factors associated with mortality in pregnant patients who underwent ECMO. METHODS: We examined the United States National Inpatient Sample database to identify hospitalizations for pregnancy from January 1, 2010 to December 31, 2016. We identified pregnant patients who underwent ECMO using International Classification of Diseases ninth and tenth revisions codes. The primary outcome was in-hospital all-cause mortality across pregnant patients who underwent ECMO for any indication. We evaluated the indication for ECMO, incidence, prevalence of risk factors, comorbidities and conditions, and their association with in-hospital mortality. RESULTS: Fifty-nine of 5'346,517 pregnant patients underwent ECMO during our study period (incidence, 1.1; 95% confidence interval [CI], 0.84-1.4 per 100,000 hospitalizations). Indications for ECMO support included respiratory failure (79.7%), cardiogenic shock (64.4%), or circulatory arrest (25.4%). Most patients (57.6%) had more than 1 indication. The overall in-hospital mortality rate was 30.5%. Mortality was 29.8% in patients with respiratory failure, 39.5% with cardiogenic shock, 46.7% with cardiac arrest, and 42.4% in those with combined diagnoses. Cardiogenic shock was associated with a significantly higher mortality rate and adjusted odds ratio 5.0 (95% CI, 1.25-27.0). Most patients (62.7%) had one or more comorbidities. CONCLUSIONS: The frequency of ECMO use across the pregnant population was low over this time period, with a mortality rate of 1 in 3 patients. Mortality was greatest in patients with cardiogenic shock. Further work is needed to understand how best to improve ECMO outcomes in pregnant patients.