Adjustments of Ventilator Parameters during Operating Room-to-ICU Transition and 28-Day Mortality.

Rationale: Lung-protective mechanical ventilation strategies have been proven beneficial in the operating room (OR) and the ICU. However, differential practices in ventilator management persist, often resulting in adjustments of ventilator parameters when transitioning patients from the OR to the ICU. Objectives: To characterize patterns of ventilator adjustments during the transition of mechanically ventilated surgical patients from the OR to the ICU and assess their impact on 28-day mortality. Methods: Hospital registry study including patients undergoing general anesthesia with continued, controlled mechanical ventilation in the ICU between 2008 and 2022. Ventilator parameters were assessed 1 hour before and 6 hours after the transition. Measurements and Main Results: Of 2,103 patients, 212 (10.1%) died within 28 days. Upon OR-to-ICU transition, VT and driving pressure decreased (-1.1 ml/kg predicted body weight [IQR, -2.0 to -0.2]; P < 0.001; and -4.3 cm H2O [-8.2 to -1.2]; P < 0.001). Concomitantly, respiratory rates increased (+5.0 breaths/min [2.0 to 7.5]; P < 0.001), resulting overall in slightly higher mechanical power (MP) in the ICU (+0.7 J/min [-1.9 to 3.0]; P < 0.001). In adjusted analysis, increases in MP were associated with a higher 28-day mortality rate (adjusted odds ratio, 1.10; 95% confidence interval, 1.06-1.14; P < 0.001; adjusted risk difference, 0.7%; 95% confidence interval, 0.4-1.0, both per 1 J/min). Conclusion: During transition of mechanically ventilated patients from the OR to the ICU, ventilator adjustments resulting in higher MP were associated with a greater risk of 28-day mortality.

Role of hemolysis on pulmonary arterial compliance and right ventricular systolic function after cardiopulmonary bypass.

BACKGROUND: Cardiopulmonary bypass (CPB) is associated with intravascular hemolysis which depletes endogenous nitric oxide (NO). The impact of hemolysis on pulmonary arterial compliance (PAC) and right ventricular systolic function has not been explored yet. We hypothesized that decreased NO availability is associated with worse PAC and right ventricular systolic function after CPB. METHODS: This is a secondary analysis of an observational cohort study in patients undergoing cardiac surgery with CPB at Massachusetts General Hospital, USA (2014-2015). We assessed PAC (stroke volume/pulmonary artery pulse pressure ratio), and right ventricular function index (RVFI) (systolic pulmonary arterial pressure/cardiac output), as well as NO consumption at 15 min, 4 h and 12 h after CPB. Patients were stratified by CPB duration. Further, we assessed the association between changes in NO consumption with PAC and RVFI between 15min and 4 h after CPB. RESULTS: PAC was lowest at 15min after CPB and improved over time (n = 50). RVFI was highest -worse right ventricular function- at CPB end and gradually decreased. Changes in hemolysis, PAC and RVFI differed over time by CPB duration. PAC inversely correlated with total pulmonary resistance (TPR). TPR and PAC positively and negatively correlated with RVFI, respectively. NO consumption between 15min and 4 h after CPB correlated with changes in PAC (-0.28 ml/mmHg, 95%CI -0.49 to -0.01, p = 0.012) and RVFI (0.14 mmHg*L-1*min, 95%CI 0.10 to 0.18, p < 0.001) after multivariable adjustments. CONCLUSION: PAC and RVFI are worse at CPB end and improve over time. Depletion of endogenous NO may contribute to explain changes in PAC and RVFI after CPB.

Increased Postoperative Opioid Consumption in the Presence of Coadministration of 5-Hydroxytryptamine Type 3 Antagonists with Acetaminophen: A Hospital Registry Study.

BACKGROUND: Acetaminophen and 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists are administered as standard prophylaxes for postoperative pain, nausea, and vomiting. Preclinical studies, however, suggest that 5-HT3 antagonists may compromise acetaminophen's analgesic effect. This hospital registry study investigates whether 5-HT3 antagonists mitigate the analgesic effect of prophylactic acetaminophen in a perioperative setting. METHODS: This study included 55,016 adult patients undergoing general anesthesia for ambulatory procedures at a tertiary healthcare center in Massachusetts from 2015 to 2022. Using binary exposure variables and a comprehensive selection of preplanned patient- and procedure-related covariates for confounder control, the authors investigated whether intraoperative 5-HT3 antagonists affected the association between pre- or intraoperative acetaminophen and postoperative opioid consumption, gauged by opioid dose in milligram oral morphine equivalents (OME) administered in the postanesthesia care unit. A multivariable, zero-inflated negative binomial regression model was applied. RESULTS: A total of 3,166 patients (5.8%) received only acetaminophen, 15,438 (28.1%) only 5-HT3 antagonists, 31,850 (57.9%) both drugs, and 4,562 (8.3%) neither drug. The median postanesthesia care unit opioid dose was 7.5 mg OME (interquartile range, 7.5 to 14.3 mg OME) among 16,640 of 55,016 (30.2%) patients who received opioids, and the mean opioid dose was 3.2 mg OME across all patients (maximum cumulative dose, 20.4 mg OME). Acetaminophen administration was associated with a -5.5% (95% CI, -9.6 to -1.4%; P = 0.009; adjusted absolute difference, -0.19 mg OME; 95% CI, -0.33 to -0.05; P = 0.009) reduction in opioid consumption among patients who did not receive a 5-HT3 antagonist, while there was no effect in patients who received a 5-HT3 antagonist (adjusted absolute difference, 0.00 mg OME; 95% CI, -0.06 to 0.05; P = 0.93; P for interaction = 0.013). CONCLUSIONS: A dose-dependent association of pre- or intraoperative acetaminophen with decreased postoperative opioid consumption was not observed when 5-HT3 antagonists were coadministered, suggesting that physicians might consider reserving 5-HT3 antagonists as rescue medication for postoperative nausea or vomiting when acetaminophen is administered for pain prophylaxis.

Association of anaesthesia provider sex with perioperative complications: a two-centre retrospective cohort study.

BACKGROUND: Previous studies suggested that surgeon sex is associated with differential patient outcomes. Whether this also applies to anaesthesia providers is unclear. We hypothesised that female sex of the primary anaesthesia provider is associated with lower risk of perioperative complications. METHODS: The first case for all adult patients undergoing anaesthesia care between 2008 and 2022 at two academic healthcare networks in the USA was included in this retrospective cohort study. The primary exposure was the sex of the anaesthesia provider who spent the most time in the operating theatre during the case. The primary outcome was intraoperative complications, defined as hypotension (mean arterial blood pressure <55 mm Hg for ≥5 cumulative minutes) or hypoxaemia (oxygen saturation <90% for >2 consecutive minutes). The co-primary outcome was 30-day adverse postoperative events (including complications, readmission, and mortality). Analyses were adjusted for a priori defined confounders. RESULTS: Among 364,429 included patients, 57,550 (15.8%) experienced intraoperative complications and 55,168 (15.1%) experienced adverse postoperative events. Care by female compared with male anaesthesia providers was associated with lower risk of intraoperative complications (adjusted odds ratio [aOR] 0.95, 95% confidence interval [CI] 0.94-0.97, P<0.001), which was magnified among non-trainees (aOR 0.84, 95% CI 0.82-0.87, P-for-interaction<0.001). Anaesthesia provider sex was not associated with the composite of adverse postoperative events (aOR 1.00, 95% CI 0.98-1.02, P=0.88). CONCLUSIONS: Care by a female anaesthesia provider was associated with a lower risk of intraoperative complications, which was magnified among non-trainees. Future studies should investigate underlying mechanisms.

Previous Coronavirus Disease-2019 Infection and Lung Mechanics in Surgical Patients: A Hospital Registry Study.

BACKGROUND: Long-term pulmonary complications have been reported after a coronavirus disease-2019 (COVID-19). We hypothesized that a history of COVID-19 is associated with a measurable decrease in baseline respiratory system compliance in patients undergoing general anesthesia. METHODS: In this hospital registry study, we included adult patients undergoing general anesthesia between January 2020 and March 2022 at a tertiary health care network in Massachusetts. We excluded patients with an American Society of Anesthesiologists physical status >IV, laryngoscopic surgeries, and patients who arrived intubated. The primary exposure was a history of COVID-19. The primary outcome was baseline respiratory system compliance (mL/cmH 2 O). Effects of severity of infection, surges (Alpha 1 , Alpha 2 , Delta, and Omicron), patient demographics, and time between infection and assessment of compliance were investigated. RESULTS: A total of 19,921 patients were included. Approximately 1386 (7.0%) patients had a history of COVID-19. A history of COVID-19 at any time before surgery was associated with a measurably lower baseline respiratory system compliance (ratio of means adj = 0.96; 95% confidence interval [CI], 0.94-0.97; P < .001; adjusted compliance difference: -1.6 mL/cmH 2 O). The association was more pronounced in patients with a severe form of COVID-19 (ratio of means adj = 0.95; 95% CI, 0.90-0.99; P = .02, adjusted compliance difference: -2 mL/cmH 2 O). Alpha 1 , Alpha 2 , and Delta surges, but not Omicron, led to a lower baseline respiratory system compliance ( P < .001, P = .02, and P < .001). The Delta surge effect was magnified in Hispanic ethnicity ( P -for-interaction = 0.003; ratio of means adj = 0.83; 95% CI, 0.74-0.93; P = .001; adjusted compliance difference: -4.6 mL/cmH 2 O). CONCLUSIONS: A history of COVID-19 infection during Alpha 1 , Alpha 2 , and Delta surges was associated with a measurably lower baseline respiratory system compliance.

Nitric oxide: Clinical applications in critically ill patients.

Inhaled nitric oxide (iNO) acts as a selective pulmonary vasodilator and it is currently approved by the FDA for the treatment of persistent pulmonary hypertension of the newborn. iNO has been demonstrated to effectively decrease pulmonary artery pressure and improve oxygenation, while decreasing extracorporeal life support use in hypoxic newborns affected by persistent pulmonary hypertension. Also, iNO seems a safe treatment with limited side effects. Despite the promising beneficial effects of NO in the preclinical literature, there is still a lack of high quality evidence for the use of iNO in clinical settings. A variety of clinical applications have been suggested in and out of the critical care environment, aiming to use iNO in respiratory failure and pulmonary hypertension of adults or as a preventative measure of hemolysis-induced vasoconstriction, ischemia/reperfusion injury and as a potential treatment of renal failure associated with cardiopulmonary bypass. In this narrative review we aim to present a comprehensive summary of the potential use of iNO in several clinical conditions with its suggested benefits, including its recent application in the scenario of the COVID-19 pandemic. Randomized controlled trials, meta-analyses, guidelines, observational studies and case-series were reported and the main findings summarized. Furthermore, we will describe the toxicity profile of NO and discuss an innovative proposed strategy to produce iNO. Overall, iNO exhibits a wide range of potential clinical benefits, that certainly warrants further efforts with randomized clinical trials to determine specific therapeutic roles of iNO.

Affiliation Bias in Peer Review of Abstracts by a Large Language Model.

This study assesses affiliation bias in peer review of medical abstracts by a commonly used large language model.

Transpulmonary Pressure as a Predictor of Successful Lung Recruitment: Reanalysis of a Multicenter International Randomized Clinical Trial.

BACKGROUND: Recruitment maneuvers are used in patients with ARDS to enhance oxygenation and lung mechanics. Heterogeneous lung and chest-wall mechanics lead to unpredictable transpulmonary pressures and could impact recruitment maneuver success. Tailoring care based on individualized transpulmonary pressure might optimize recruitment, preventing overdistention. This study aimed to identify the optimal transpulmonary pressure for effective recruitment and to explore its association with baseline characteristics. METHODS: We performed post hoc analysis on the Esophageal Pressure Guided Ventilation (EpVent2) trial. We estimated the dose-response relationship between end-recruitment end-inspiratory transpulmonary pressure and the change in lung elastance after a recruitment maneuver by using logistic regression weighted by a generalized propensity score. A positive change in lung elastance was indicative of overdistention. We examined how patient characteristics, disease severity markers, and respiratory parameters predict transpulmonary pressure by using multivariate linear regression models and dominance analyses. RESULTS: Of 121 subjects, 43.8% had a positive change in lung elastance. Subjects with a positive change in lung elastance had a mean ± SD transpulmonary pressure of 15.1 ± 4.9 cm H2O, compared with 13.9 ± 3.9 cm H2O in those with a negative change in lung elastance. Higher transpulmonary pressure was associated with increased probability of a positive change in lung elastance (adjusted odds ratio 1.35 per 1 cm H2O of transpulmonary pressure, 95% CI 1.13-1.61; P = .001), which indicated an S-shaped dose-response curve, with overdistention probability > 50% at transpulmonary pressure values > 18.3 cm H2O. The volume of recruitment was transpulmonary pressure-dependent (P < .001; R2 = 0.49) and inversely related to a change in lung elastance after adjusting for baseline lung elastance (P < .001; R2= 0.43). Negative correlations were observed between transpulmonary pressure and body mass index, PEEP, Sequential Organ Failure Assessment score, and PaO2 /FIO2 , whereas baseline lung elastance showed a positive correlation. The body mass index emerged as the dominant negative predictor of transpulmonary pressure (ranking 1; contribution to R2 = 0.08), whereas pre-recruitment elastance was the sole positive predictor (contribution to R2 = 0.06). CONCLUSIONS: Higher end-recruitment transpulmonary pressure increases the volume of recruitment but raises the risk of overdistention, providing the rationale for transpulmonary pressure to be used as a clinical target. Predictors, for example, body mass index, could guide recruitment maneuver individualization to balance adequate volume gain with overdistention.

Assessing ChatGPT's ability to emulate human reviewers in scientific research: A descriptive and qualitative approach.

BACKGROUND: ChatGPT is an AI platform whose relevance in the peer review of scientific articles is steadily growing. Nonetheless, it has sparked debates over its potential biases and inaccuracies. This study aims to assess ChatGPT's ability to qualitatively emulate human reviewers in scientific research. METHODS: We included the first submitted version of the latest twenty original research articles published by the 3rd of July 2023, in a high-profile medical journal. Each article underwent evaluation by a minimum of three human reviewers during the initial review stage. Subsequently, three researchers with medical backgrounds and expertise in manuscript revision, independently and qualitatively assessed the agreement between the peer reviews generated by ChatGPT version GPT-4 and the comments provided by human reviewers for these articles. The level of agreement was categorized into complete, partial, none, or contradictory. RESULTS: 720 human reviewers' comments were assessed. There was a good agreement between the three assessors (Overall kappa >0.6). ChatGPT's comments demonstrated complete agreement in terms of quality and substance with 48 (6.7 %) human reviewers' comments, partially agreed with 92 (12.8 %), identifying issues necessitating further elaboration or recommending supplementary steps to address concerns, had no agreement with a significant 565 (78.5 %), and contradicted 15 (2.1 %). ChatGPT comments on methods had the lowest proportion of complete agreement (13 comments, 3.6 %), while general comments on the manuscript displayed the highest proportion of complete agreement (17 comments, 22.1 %). CONCLUSION: ChatGPT version GPT-4 has a limited ability to emulate human reviewers within the peer review process of scientific research.

Intraoperative Opioid Waste and Association of Intraoperative Opioid Dose with Postoperative Adverse Outcomes: A Hospital Registry Study.

INTRODUCTION: Perioperative opioid use has been associated with adverse clinical outcomes. Additionally, opioid disposal carries significant costs, due to the waste of pharmaceutical products and the time needed by skilled labor to report the waste. In this study, we aimed to estimate costs and predict factors of opioid-associated intraoperative product waste, as well as to evaluate whether higher intraoperative opioid doses are associated with increased risk of adverse postoperative outcomes. METHODS: We included 170,607 patients undergoing general anesthesia and receiving intraoperative fentanyl, hydromorphone, or morphine at Beth Israel Deaconess Medical Center, Boston, MA, USA, between January 2010 and June 2020. We estimated product waste-associated costs based on various opioid syringe sizes and determined predictors of opioid waste. Further, we evaluated whether higher opioid doses were associated with postoperative adverse events according to the severity-indexed, incident report-based medication error-reporting program classification. The primary outcome included post-extubation desaturation, postoperative nausea or vomiting, or postoperative somnolence or sedation. RESULTS: The use of the smallest syringe sizes (50 mcg for fentanyl, 0.2 mg for hydromorphone, and 2 mg for morphine) resulted in the lowest product waste-associated costs. The main predictor of opioid waste was the administration of more than one intraoperative opioid (adjusted odds ratio [aOR] = 7.64, 95% CI 7.40-7.89, P < 0.001). Intraoperative doses of fentanyl > 50-100 mcg (aOR = 1.17 [1.10-1.25], P < 0.001, adjusted risk difference [ARD] 2%) and > 100 mcg (aOR = 1.24 [1.16-1.33], P < 0.001, ARD 3%), hydromorphone > 1 mg (aOR = 1.13 [1.06-1.20], P < 0.001, ARD 2%), and morphine > 2-4 mg (aOR = 1.26 [1.02-1.56], P = 0.04, ARD 3%) and > 4 mg (aOR = 1.45 [1.18-1.77], P < 0.001, ARD 5%) were associated with higher risk of the primary outcome. CONCLUSION: Smaller syringe sizes of intraoperative opioids may help to reduce product waste and associated costs, as well postoperative adverse events through utilization of lower intraoperative opioid doses.

The association between intraoperative low driving pressure ventilation and perioperative healthcare-associated costs: A retrospective multicenter cohort study.

STUDY OBJECTIVE: A low dynamic driving pressure during mechanical ventilation for general anesthesia has been associated with a lower risk of postoperative respiratory complications (PRC), a key driver of healthcare costs. It is, however, unclear whether maintaining low driving pressure is clinically relevant to measure and contain costs. We hypothesized that a lower dynamic driving pressure is associated with lower costs. DESIGN: Multicenter retrospective cohort study. SETTING: Two academic healthcare networks in New York and Massachusetts, USA. PATIENTS: 46,715 adult surgical patients undergoing general anesthesia for non-ambulatory (inpatient and same-day admission) surgery between 2016 and 2021. INTERVENTIONS: The primary exposure was the median intraoperative dynamic driving pressure. MEASUREMENTS: The primary outcome was direct perioperative healthcare-associated costs, which were matched with data from the Healthcare Cost and Utilization Project-National Inpatient Sample (HCUP-NIS) to report absolute differences in total costs in United States Dollars (US$). We assessed effect modification by patients' baseline risk of PRC (score for prediction of postoperative respiratory complications [SPORC] ≥ 7) and effect mediation by rates of PRC (including post-extubation saturation < 90%, re-intubation or non-invasive ventilation within 7 days) and other major complications. MAIN RESULTS: The median intraoperative dynamic driving pressure was 17.2cmH2O (IQR 14.0-21.3cmH2O). In adjusted analyses, every 5cmH2O reduction in dynamic driving pressure was associated with a decrease of -0.7% in direct perioperative healthcare-associated costs (95%CI -1.3 to -0.1%; p = 0.020). When a dynamic driving pressure below 15cmH2O was maintained, -US$340 lower total perioperative healthcare-associated costs were observed (95%CI -US$546 to -US$132; p = 0.001). This association was limited to patients at high baseline risk of PRC (n = 4059; -US$1755;97.5%CI -US$2495 to -US$986; p < 0.001), where lower risks of PRC and other major complications mediated 10.7% and 7.2% of this association (p < 0.001 and p = 0.015, respectively). CONCLUSIONS: Intraoperative mechanical ventilation targeting low dynamic driving pressures could be a relevant measure to reduce perioperative healthcare-associated costs in high-risk patients.

BMP7 promotes cardiomyocyte regeneration in zebrafish and adult mice.

Zebrafish have a lifelong cardiac regenerative ability after damage, whereas mammals lose this capacity during early postnatal development. This study investigated whether the declining expression of growth factors during postnatal mammalian development contributes to the decrease of cardiomyocyte regenerative potential. Besides confirming the proliferative ability of neuregulin 1 (NRG1), interleukin (IL)1b, receptor activator of nuclear factor kappa-Β ligand (RANKL), insulin growth factor (IGF)2, and IL6, we identified other potential pro-regenerative factors, with BMP7 exhibiting the most pronounced efficacy. Bmp7 knockdown in neonatal mouse cardiomyocytes and loss-of-function in adult zebrafish during cardiac regeneration reduced cardiomyocyte proliferation, indicating that Bmp7 is crucial in the regenerative stages of mouse and zebrafish hearts. Conversely, bmp7 overexpression in regenerating zebrafish or administration at post-mitotic juvenile and adult mouse stages, in vitro and in vivo following myocardial infarction, enhanced cardiomyocyte cycling. Mechanistically, BMP7 stimulated proliferation through BMPR1A/ACVR1 and ACVR2A/BMPR2 receptors and downstream SMAD5, ERK, and AKT signaling. Overall, BMP7 administration is a promising strategy for heart regeneration.

Inhaled Nitric Oxide in Acute Respiratory Distress Syndrome Subsets: Rationale and Clinical Applications.

Acute respiratory distress syndrome (ARDS) is a life-threatening condition, characterized by diffuse inflammatory lung injury. Since the coronavirus disease 2019 (COVID-19) pandemic spread worldwide, the most common cause of ARDS has been the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Both the COVID-19-associated ARDS and the ARDS related to other causes-also defined as classical ARDS-are burdened by high mortality and morbidity. For these reasons, effective therapeutic interventions are urgently needed. Among them, inhaled nitric oxide (iNO) has been studied in patients with ARDS since 1993 and it is currently under investigation. In this review, we aim at describing the biological and pharmacological rationale of iNO treatment in ARDS by elucidating similarities and differences between classical and COVID-19 ARDS. Thereafter, we present the available evidence on the use of iNO in clinical practice in both types of respiratory failure. Overall, iNO seems a promising agent as it could improve the ventilation/perfusion mismatch, gas exchange impairment, and right ventricular failure, which are reported in ARDS. In addition, iNO may act as a viricidal agent and prevent lung hyperinflammation and thrombosis of the pulmonary vasculature in the specific setting of COVID-19 ARDS. However, the current evidence on the effects of iNO on outcomes is limited and clinical studies are yet to demonstrate any survival benefit by administering iNO in ARDS.

Mechanical power and 30-day mortality in mechanically ventilated, critically ill patients with and without Coronavirus Disease-2019: a hospital registry study.

BACKGROUND: Previous studies linked a high intensity of ventilation, measured as mechanical power, to mortality in patients suffering from "classic" ARDS. By contrast, mechanically ventilated patients with a diagnosis of COVID-19 may present with intact pulmonary mechanics while undergoing mechanical ventilation for longer periods of time. We investigated whether an association between higher mechanical power and mortality is modified by a diagnosis of COVID-19. METHODS: This retrospective study included critically ill, adult patients who were mechanically ventilated for at least 24 h between March 2020 and December 2021 at a tertiary healthcare facility in Boston, Massachusetts. The primary exposure was median mechanical power during the first 24 h of mechanical ventilation, calculated using a previously validated formula. The primary outcome was 30-day mortality. As co-primary analysis, we investigated whether a diagnosis of COVID-19 modified the primary association. We further investigated the association between mechanical power and days being alive and ventilator free and effect modification of this by a diagnosis of COVID-19. Multivariable logistic regression, effect modification and negative binomial regression analyses adjusted for baseline patient characteristics, severity of disease and in-hospital factors, were applied. RESULTS: 1,737 mechanically ventilated patients were included, 411 (23.7%) suffered from COVID-19. 509 (29.3%) died within 30 days. The median mechanical power during the first 24 h of ventilation was 19.3 [14.6-24.0] J/min in patients with and 13.2 [10.2-18.0] J/min in patients without COVID-19. A higher mechanical power was associated with 30-day mortality (ORadj 1.26 per 1-SD, 7.1J/min increase; 95% CI 1.09-1.46; p = 0.002). Effect modification and interaction analysis did not support that this association was modified by a diagnosis of COVID-19 (95% CI, 0.81-1.38; p-for-interaction = 0.68). A higher mechanical power was associated with a lower number of days alive and ventilator free until day 28 (IRRadj 0.83 per 7.1 J/min increase; 95% CI 0.75-0.91; p < 0.001, adjusted risk difference - 2.7 days per 7.1J/min increase; 95% CI - 4.1 to - 1.3). CONCLUSION: A higher mechanical power is associated with elevated 30-day mortality. While patients with COVID-19 received mechanical ventilation with higher mechanical power, this association was independent of a concomitant diagnosis of COVID-19.

Inflammatory subphenotypes in patients at risk of ARDS: evidence from the LIPS-A trial.

PURPOSE: Latent class analysis (LCA) has identified hyper- and non-hyper-inflammatory subphenotypes in patients with acute respiratory distress syndrome (ARDS). It is unknown how early inflammatory subphenotypes can be identified in patients at risk of ARDS. We aimed to test for inflammatory subphenotypes upon presentation to the emergency department. METHODS: LIPS-A was a trial of aspirin to prevent ARDS in at-risk patients presenting to the emergency department. In this secondary analysis, we performed LCA using clinical, blood test, and biomarker variables. RESULTS: Among 376 (96.4%) patients from the LIPS-A trial, two classes were identified upon presentation to the emergency department (day 0): 72 (19.1%) patients demonstrated characteristics of a hyper-inflammatory and 304 (80.9%) of a non-hyper-inflammatory subphenotype. 15.3% of patients in the hyper- and 8.2% in the non-hyper-inflammatory class developed ARDS (p = 0.07). Patients in the hyper-inflammatory class had fewer ventilator-free days (median [interquartile range, IQR] 28[23-28] versus 28[27-28]; p = 0.010), longer intensive care unit (3[2-6] versus 0[0-3] days; p < 0.001) and hospital (9[6-18] versus 5[3-9] days; p < 0.001) length of stay, and higher 1-year mortality (34.7% versus 20%; p = 0.008). Subphenotypes were identified on day 1 and 4 in a subgroup with available data (n = 244). 77.9% of patients remained in their baseline class throughout day 4. Patients with a hyper-inflammatory subphenotype throughout the study period (n = 22) were at higher risk of ARDS (36.4% versus 10.4%; p = 0.003). CONCLUSION: Hyper- and non-hyper-inflammatory subphenotypes may precede ARDS development, remain identifiable over time, and can be identified upon presentation to the emergency department. A hyper-inflammatory subphenotype predicts worse outcomes.

Extracorporeal Gas Exchange for Acute Respiratory Distress Syndrome: Open Questions, Controversies and Future Directions.

Veno-venous extracorporeal membrane oxygenation (V-V ECMO) in acute respiratory distress syndrome (ARDS) improves gas exchange and allows lung rest, thus minimizing ventilation-induced lung injury. In the last forty years, a major technological and clinical improvement allowed to dramatically improve the outcome of patients treated with V-V ECMO. However, many aspects of the care of patients on V-V ECMO remain debated. In this review, we will focus on main issues and controversies on caring of ARDS patients on V-V ECMO support. Particularly, the indications to V-V ECMO and the feasibility of a less invasive extracorporeal carbon dioxide removal will be discussed. Moreover, the controversies on management of mechanical ventilation, prone position and sedation will be explored. In conclusion, we will discuss evidences on transfusions and management of anticoagulation, also focusing on patients who undergo simultaneous treatment with ECMO and renal replacement therapy. This review aims to discuss all these clinical aspects with an eye on future directions and perspectives.

Hospital-Acquired Infections in Critically Ill Patients With COVID-19.

BACKGROUND: Few small studies have described hospital-acquired infections (HAIs) occurring in patients with COVID-19. RESEARCH QUESTION: What characteristics in critically ill patients with COVID-19 are associated with HAIs and how are HAIs associated with outcomes in these patients? STUDY DESIGN AND METHODS: Multicenter retrospective analysis of prospectively collected data including adult patients with severe COVID-19 admitted to eight Italian hub hospitals from February 20, 2020, through May 20, 2020. Descriptive statistics and univariate and multivariate Weibull regression models were used to assess incidence, microbial cause, resistance patterns, risk factors (ie, demographics, comorbidities, exposure to medication), and impact on outcomes (ie, ICU discharge, length of ICU and hospital stays, and duration of mechanical ventilation) of microbiologically confirmed HAIs. RESULTS: Of the 774 included patients, 359 patients (46%) demonstrated 759 HAIs (44.7 infections/1,000 ICU patient-days; 35% multidrug-resistant [MDR] bacteria). Ventilator-associated pneumonia (VAP; n = 389 [50%]), bloodstream infections (BSIs; n = 183 [34%]), and catheter-related BSIs (n = 74 [10%]) were the most frequent HAIs, with 26.0 (95% CI, 23.6-28.8) VAPs per 1,000 intubation-days, 11.7 (95% CI, 10.1-13.5) BSIs per 1,000 ICU patient-days, and 4.7 (95% CI, 3.8-5.9) catheter-related BSIs per 1,000 ICU patient-days. Gram-negative bacteria (especially Enterobacterales) and Staphylococcus aureus caused 64% and 28% of cases of VAP, respectively. Variables independently associated with infection were age, positive end expiratory pressure, and treatment with broad-spectrum antibiotics at admission. Two hundred thirty-four patients (30%) died in the ICU (15.3 deaths/1,000 ICU patient-days). Patients with HAIs complicated by septic shock showed an almost doubled mortality rate (52% vs 29%), whereas noncomplicated infections did not affect mortality. HAIs prolonged mechanical ventilation (median, 24 days [interquartile range (IQR), 14-39 days] vs 9 days [IQR, 5-13 days]; P < .001), ICU stay (24 days [IQR, 16-41 days] vs 9 days [IQR, 6-14 days]; P = .003), and hospital stay (42 days [IQR, 25-59 days] vs 23 days [IQR, 13-34 days]; P < .001). INTERPRETATION: Critically ill patients with COVID-19 are at high risk for HAIs, especially VAPs and BSIs resulting from MDR organisms. HAIs prolong mechanical ventilation and hospitalization, and HAIs complicated by septic shock almost double mortality. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT04388670; URL: www.clinicaltrials.gov.