Palliative Care Utilization in Patients Requiring Extracorporeal Membrane Oxygenation: An Observational Study.

Palliative care (PC) is a model of care centered around improving the quality of life for individuals with life-limiting illnesses. Few studies have examined its impact in patients on extracorporeal membrane oxygenation (ECMO). We aimed to describe demographics, clinical characteristics, and complications associated with PC consultation in adult patients requiring ECMO support. We analyzed data from an ECMO registry, including patients aged 18 years and older who have received either venoarterial (VA)- or venovenous (VV)-ECMO support between July 2016 and September 2021. We used analysis of variance and Fisher exact tests to identify factors associated with PC consultation. Of 256, 177 patients (69.1%) received VA-ECMO support and 79 (30.9%) received VV-ECMO support. Overall, 115 patients (44.9%) received PC consultation while on ECMO. Patients receiving PC consultation were more likely to be non-white (47% vs. 53%, p = 0.016), have an attending physician from a medical versus surgical specialty (65.3% vs. 39.6%), have VV-ECMO (77.2% vs. 30.5%, p < 0.001), and have longer ECMO duration (6.2 vs. 23.0, p < 0.001). Patients were seen by the PC team on an average of 7.6 times (range, 1-35), with those who died having significantly more visits (11.2 vs. 5.6, p < 0.001) despite the shorter hospital stay. The average time from cannulation to the first PC visit was 5.3 ± 5 days. Congestive heart failure in VA-ECMO, coronavirus disease 2019 infection in VV-ECMO, and non-white race and longer ECMO duration for all patients were associated with PC consultation. We found that despite the benefits of PC, it is underused in this population.

Challenges in determining death by neurologic criteria in extracorporeal membrane oxygenation - A single center experience.

INTRODUCTION: Apnea test (AT) in patients on extracorporeal membrane oxygenation (ECMO) support is challenging, leading to variation in determining death by neurologic criteria (DNC). We aim to describe the diagnostic criteria and barriers for DNC in adults on ECMO in a tertiary care center. METHODS: A retrospective review of a prospective observational standardized neuromonitoring study was conducted in adult VA- and VV-ECMO patients at a tertiary center from June 2016 to March 2022. Brain death was defined according to the 2010 American Academy of Neurology guidelines and following the 2020 World Brain Death Project recommendations for performing AT in ECMO patients. RESULTS: Eight (2.7%) ECMO patients (median age = 44 years, 75% male, 50% VA-ECMO) met criteria for DNC, six (75%) of whom were determined with AT. In the other two patients who did not undergo AT due to safety concerns, ancillary tests (transcranial doppler and electroencephalography) were consistent with DNC. An additional seven (2.3%) patients (median age = 55 years, 71% male, 86% VA-ECMO) were noted to have absent brainstem reflexes but failed to complete determination of DNC as they underwent withdrawal of life-sustaining treatment (WLST) before a full evaluation was completed. In these patients, AT was never performed, and ancillary tests were inconsistent with either neurological exam findings and/or neuroimaging supporting DNC, or with each other. CONCLUSION: AT was used safely and successfully in 6 of the 8 ECMO patients diagnosed with DNC and was always consistent with the neurological exam and imaging findings, as opposed to ancillary tests alone.

Extracorporeal membrane oxygenation in adults receiving haematopoietic cell transplantation: an international expert statement.

Combined advances in haematopoietic cell transplantation (HCT) and intensive care management have improved the survival of patients with haematological malignancies admitted to the intensive care unit. In cases of refractory respiratory failure or refractory cardiac failure, these advances have led to a renewed interest in advanced life support therapies, such as extracorporeal membrane oxygenation (ECMO), previously considered inappropriate for these patients due to their poor prognosis. Given the scarcity of evidence-based guidelines on the use of ECMO in patients receiving HCT and the need to provide equitable and sustainable access to ECMO, the European Society of Intensive Care Medicine, the Extracorporeal Life Support Organization, and the International ECMO Network aimed to develop an expert consensus statement on the use of ECMO in adult patients receiving HCT. A steering committee with expertise in ECMO and HCT searched the literature for relevant articles on ECMO, HCT, and immune effector cell therapy, and developed opinion statements through discussions following a Quaker-based consensus approach. An international panel of experts was convened to vote on these expert opinion statements following the Research and Development/University of California, Los Angeles Appropriateness Method. The Appraisal of Guidelines for Research and Evaluation statement was followed to prepare this Position Paper. 36 statements were drafted by the steering committee, 33 of which reached strong agreement after the first voting round. The remaining three statements were discussed by all members of the steering committee and expert panel, and rephrased before an additional round of voting. At the conclusion of the process, 33 statements received strong agreement and three weak agreement. This Position Paper could help to guide intensivists and haematologists during the difficult decision-making process regarding ECMO candidacy in adult patients receiving HCT. The statements could also serve as a basis for future research focused on ECMO selection criteria and bedside management.

Multisite implementation of a workflow-integrated machine learning system to optimize COVID-19 hospital admission decisions.

Demand has outstripped healthcare supply during the coronavirus disease 2019 (COVID-19) pandemic. Emergency departments (EDs) are tasked with distinguishing patients who require hospital resources from those who may be safely discharged to the community. The novelty and high variability of COVID-19 have made these determinations challenging. In this study, we developed, implemented and evaluated an electronic health record (EHR) embedded clinical decision support (CDS) system that leverages machine learning (ML) to estimate short-term risk for clinical deterioration in patients with or under investigation for COVID-19. The system translates model-generated risk for critical care needs within 24 h and inpatient care needs within 72 h into rapidly interpretable COVID-19 Deterioration Risk Levels made viewable within ED clinician workflow. ML models were derived in a retrospective cohort of 21,452 ED patients who visited one of five ED study sites and were prospectively validated in 15,670 ED visits that occurred before (n = 4322) or after (n = 11,348) CDS implementation; model performance and numerous patient-oriented outcomes including in-hospital mortality were measured across study periods. Incidence of critical care needs within 24 h and inpatient care needs within 72 h were 10.7% and 22.5%, respectively and were similar across study periods. ML model performance was excellent under all conditions, with AUC ranging from 0.85 to 0.91 for prediction of critical care needs and 0.80-0.90 for inpatient care needs. Total mortality was unchanged across study periods but was reduced among high-risk patients after CDS implementation.

Critically Ill Patients Treated for Chimeric Antigen Receptor-Related Toxicity: A Multicenter Study.

OBJECTIVES: To report the epidemiology, treatments, and outcomes of adult patients admitted to the ICU after cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome. DESIGN: Retrospective cohort study. SETTING: Nine centers across the U.S. part of the chimeric antigen receptor-ICU initiative. PATIENTS: Adult patients treated with chimeric antigen receptor T-cell therapy who required ICU admission between November 2017 and May 2019. INTERVENTIONS: Demographics, toxicities, specific interventions, and outcomes were collected. RESULTS: One-hundred five patients treated with axicabtagene ciloleucel required ICU admission for cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome during the study period. At the time of ICU admission, the majority of patients had grade 3-4 toxicities (66.7%); 15.2% had grade 3-4 cytokine release syndrome and 64% grade 3-4 immune effector cell-associated neurotoxicity syndrome. During ICU stay, cytokine release syndrome was observed in 77.1% patients and immune effector cell-associated neurotoxicity syndrome in 84.8% of patients; 61.9% patients experienced both toxicities. Seventy-nine percent of patients developed greater than or equal to grade 3 toxicities during ICU stay, however, need for vasopressors (18.1%), mechanical ventilation (10.5%), and dialysis (2.9%) was uncommon. Immune Effector Cell-Associated Encephalopathy score less than 3 (69.7%), seizures (20.2%), status epilepticus (5.7%), motor deficits (12.4%), and cerebral edema (7.9%) were more prevalent. ICU mortality was 8.6%, with only three deaths related to cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome. Median overall survival time was 10.4 months (95% CI, 6.64-not available mo). Toxicity grade or organ support had no impact on overall survival; higher cumulative corticosteroid doses were associated to decreased overall and progression-free survival. CONCLUSIONS: This is the first study to describe a multicenter cohort of patients requiring ICU admission with cytokine release syndrome or immune effector cell-associated neurotoxicity syndrome after chimeric antigen receptor T-cell therapy. Despite severe toxicities, organ support and in-hospital mortality were low in this patient population.

Incidence and Outcomes of Respiratory Failure after Nonmyeloablative Related Haploidentical Blood or Marrow Transplantation.

Respiratory failure is a devastating complication of allogenic blood or marrow transplantation (BMT). Prior data suggest that respiratory failure occurs in 20% of BMT recipients and acute respiratory distress syndrome (ARDS) occurs in 15%. Nonmyeloablative (NMA) haploidentical BMT allows donor pool expansion and may decrease complications. Incidence, outcomes, and risk factors for respiratory failure after NMA haploidentical BMT are unknown. This study aimed to determine the incidence of respiratory failure after NMA haploidentical BMT and explore outcomes and risk factors for respiratory failure. In this single-center, retrospective study of all patients age >18 years undergoing NMA haploidentical BMT between 2004 and 2016, the primary outcome was respiratory failure, marked by the use of high-flow nasal cannula oxygen, noninvasive ventilation (NIV), or invasive mechanical ventilation (IMV) within 2 years after BMT. Respiratory failure incidence is reported as incidence rate ratio (IRR) with 95% confidence interval (CI). Unadjusted and multivariable Cox proportional hazards models with adjustment for a priori identified patient-level characteristics were used. Results are presented as hazard ratio (HR) with 95% CI. A total of 520 patients underwent NMA haploidentical BMT, of whom 82 (15.8%) developed respiratory failure (IRR, 0.114/person-year) at a median of 0.34 year (interquartile range, 0.06 to 0.75 year) after BMT. Older age (HR, 1.04; 95% CI, 1.02 to 1.07), transplantation for myelodysplastic syndrome (MDS) (HR, 1.99; 95% CI, 1.07 to 3.72), and parent donor (HR, 3.49; 95% CI, 1.32 to 9.26) were associated with an increased risk of respiratory failure, whereas higher pretransplantation lung diffusion capacity of carbon monoxide (DLCO; % of predicted) was associated with lower risk (HR, 0.98; 95% CI, 0.77 to 0.99). Sixty-one patients (11.7%) required IMV, and 30 were successfully extubated. Only 37 patients (7%) had ARDS. Of the 82 patients with respiratory failure, 43 (52.4%) died during index hospitalization and 61 (77.2%) died by 2 years post-transplantation. Only 40 (49%) had nonrelapse mortality. The incidence of respiratory failure and ARDS after NMA haploidentical BMT is modest at 15% by 2 years post-transplantation. Despite successful extubation in >50% of patients, respiratory failure, regardless of cause, is associated with a high rate of death by 2 years from both relapse and nonrelapse causes. Age, BMT for MDS, parental donor, and pretransplantation DLCO are risk factors for respiratory failure.

Review of the published literature to characterise clinical excellence in COVID-19 care.

COVID-19 continues to be a major source of global morbidity and mortality. It abruptly stressed healthcare systems early in 2020 and the pressures continue. Devastating hardships have been endured by individuals, families and communities; the losses will be felt for years to come. As healthcare professionals and organisations stepped up to respond to the overwhelming number of cases, it is understandable that the focus has been primarily on coping with the quantity of the demand. During a pandemic, it is not surprising that few papers have drawn attention to the quality of the care delivered to those afflicted with illness. Despite the challenges, clinicians caring for patients with COVID-19 have risen to the occasion. This manuscript highlights aspirational examples from the published literature of thoughtful and superb care of patients with COVID-19 using an established framework for clinical excellence (formulated by the Miller-Coulson Academy of Clinical Excellence).

Calculated Plasma Volume Status Is Associated With Mortality in Acute Respiratory Distress Syndrome.

The optimal method to assess fluid overload in acute respiratory distress syndrome is not known, and current techniques have limitations. Plasma volume status has emerged as a noninvasive method to assess volume status and is defined as the percentage alteration from ideal plasma volume. We hypothesized that plasma volume status would suggest the presence of significant excess volume and therefore correlate with mortality in acute respiratory distress syndrome. DESIGN AND SETTING: This is a retrospective cohort study of subjects enrolled in four previously completed National Heart Lung and Blood Institute-sponsored acute respiratory distress syndrome trials, using data from the National Institutes of Health Biologic Specimen and Data Repository Information Coordinating Center repository. PATIENTS: Study subjects included 3,165 patients with acute respiratory distress syndrome previously enrolled in National Heart Lung and Blood Institute-sponsored acute respiratory distress syndrome trials. MEASUREMENTS AND MAIN RESULTS: The exposure variable of interest was plasma volume status, calculated as the percentage alteration of actual plasma volume calculated on the basis of weight and hematocrit using sex-specific constants. We performed Kaplan-Meier survival analysis and univariable and adjusted Cox proportional hazard models to determine the association of plasma volume status with 60-day mortality. The median age of subjects was 52 years (interquartile range, 40-63 yr). Median plasma volume status was 5.9% (interquartile range, -2.4% to 13.6%), and overall, 68% of subjects had positive plasma volume status suggesting plasma volume higher than ideal plasma volume. In adjusted models, plasma volume status greater than median was associated with 38% greater risk for mortality (hazard ratio, 1.38; 95% CI, 1.20-1.59; p < 0.001). Each interquartile range increase in plasma volume status was associated with greater mortality in adjusted models (hazard ratio, 1.24 per interquartile range increase; 95% CI, 1.13-1.36; p < 0.001). Plasma volume status greater than median was associated with fewer ventilator-free days (18 vs 19 d; p = 0.0026) and ICU-free days (15 vs 17 d; p = 0.0001). CONCLUSIONS: Plasma volume status is independently associated with mortality, ICU-free days, and ventilator-free days among subjects with acute respiratory distress syndrome. Plasma volume status could be considered for risk-stratification and to direct therapy, particularly fluid management.

Pathophysiology of Brain Injury and Neurological Outcome in Acute Respiratory Distress Syndrome: A Scoping Review of Preclinical to Clinical Studies.

Acute respiratory distress syndrome (ARDS) has been associated with secondary acute brain injury (ABI). However, there is sparse literature on the mechanism of lung-mediated brain injury and prevalence of ARDS-associated secondary ABI. We aimed to review and elucidate potential mechanisms of ARDS-mediated ABI from preclinical models and assess the prevalence of ABI and neurological outcome in ARDS with clinical studies. We conducted a systematic search of PubMed and five other databases reporting ABI and ARDS through July 6, 2020 and included studies with ABI and neurological outcome occurring after ARDS. We found 38 studies (10 preclinical studies with 143 animals; 28 clinical studies with 1175 patients) encompassing 9 animal studies (n = 143), 1 in vitro study, 12 studies on neurocognitive outcomes (n = 797), 2 clinical observational studies (n = 126), 1 neuroimaging study (n = 15), and 13 clinical case series/reports (n = 15). Six ARDS animal studies demonstrated evidence of neuroinflammation and neuronal damage within the hippocampus. Five animal studies demonstrated altered cerebral blood flow and increased intracranial pressure with the use of lung-protective mechanical ventilation. High frequency of ARDS-associated secondary ABI or poor neurological outcome was observed ranging 82-86% in clinical observational studies. Of the clinically reported ABIs (median age 49 years, 46% men), the most common injury was hemorrhagic stroke (25%), followed by hypoxic ischemic brain injury (22%), diffuse cerebral edema (11%), and ischemic stroke (8%). Cognitive impairment in patients with ARDS (n = 797) was observed in 87% (range 73-100%) at discharge, 36% (range 32-37%) at 6 months, and 30% (range 25-45%) at 1 year. Mechanisms of ARDS-associated secondary ABI include primary hypoxic ischemic injury from hypoxic respiratory failure, secondary injury, such as lung injury induced neuroinflammation, and increased intracranial pressure from ARDS lung-protective mechanical ventilation strategy. In summary, paucity of clinical data exists on the prevalence of ABI in patients with ARDS. Hemorrhagic stroke and hypoxic ischemic brain injury were commonly observed. Persistent cognitive impairment was highly prevalent in patients with ARDS.

Variation in Early Management Practices in Moderate-to-Severe ARDS in the United States: The Severe ARDS: Generating Evidence Study.

BACKGROUND: Although specific interventions previously demonstrated benefit in patients with ARDS, use of these interventions is inconsistent, and patient mortality remains high. The impact of variability in center management practices on ARDS mortality rates remains unknown. RESEARCH QUESTION: What is the impact of treatment variability on mortality in patients with moderate to severe ARDS in the United States? STUDY DESIGN AND METHODS: We conducted a multicenter, observational cohort study of mechanically ventilated adults with ARDS and Pao2 to Fio2 ratio of ≤ 150 with positive end-expiratory pressure of ≥ 5 cm H2O, who were admitted to 29 US centers between October 1, 2016, and April 30, 2017. The primary outcome was 28-day in-hospital mortality. Center variation in ventilator management, adjunctive therapy use, and mortality also were assessed. RESULTS: A total of 2,466 patients were enrolled. Median baseline Pao2 to Fio2 ratio was 105 (interquartile range, 78.0-129.0). In-hospital 28-day mortality was 40.7%. Initial adherence to lung protective ventilation (LPV; tidal volume, ≤ 6.5 mL/kg predicted body weight; plateau pressure, or when unavailable, peak inspiratory pressure, ≤ 30 mm H2O) was 31.4% and varied between centers (0%-65%), as did rates of adjunctive therapy use (27.1%-96.4%), methods used (neuromuscular blockade, prone positioning, systemic steroids, pulmonary vasodilators, and extracorporeal support), and mortality (16.7%-73.3%). Center standardized mortality ratios (SMRs), calculated using baseline patient-level characteristics to derive expected mortality rate, ranged from 0.33 to 1.98. Of the treatment-level factors explored, only center adherence to early LPV was correlated with SMR. INTERPRETATION: Substantial center-to-center variability exists in ARDS management, suggesting that further opportunities for improving ARDS outcomes exist. Early adherence to LPV was associated with lower center mortality and may be a surrogate for overall quality of care processes. Future collaboration is needed to identify additional treatment-level factors influencing center-level outcomes. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT03021824; URL: www.clinicaltrials.gov.

Operational Recommendations for Scarce Resource Allocation in a Public Health Crisis.

The coronavirus disease 2019 pandemic may require rationing of various medical resources if demand exceeds supply. Theoretical frameworks for resource allocation have provided much needed ethical guidance, but hospitals still need to address objective practicalities and legal vetting to operationalize scarce resource allocation schemata. To develop operational scarce resource allocation processes for public health catastrophes, including the coronavirus disease 2019 pandemic, five health systems in Maryland formed a consortium-with diverse expertise and representation-representing more than half of all hospitals in the state. Our efforts built on a prior statewide community engagement process that determined the values and moral reference points of citizens and health-care professionals regarding the allocation of ventilators during a public health catastrophe. Through a partnership of health systems, we developed a scarce resource allocation framework informed by citizens' values and by general expert consensus. Allocation schema for mechanical ventilators, ICU resources, blood components, novel therapeutics, extracorporeal membrane oxygenation, and renal replacement therapies were developed. Creating operational algorithms for each resource posed unique challenges; each resource's varying nature and underlying data on benefit prevented any single algorithm from being universally applicable. The development of scarce resource allocation processes must be iterative, legally vetted, and tested. We offer our processes to assist other regions that may be faced with the challenge of rationing health-care resources during public health catastrophes.

The chimeric antigen receptor-intensive care unit (CAR-ICU) initiative: Surveying intensive care unit practices in the management of CAR T-cell associated toxicities.

PURPOSE: A task force of experts from 11 United States (US) centers, sought to describe practices for managing chimeric antigen receptor (CAR) T-cell toxicity in the intensive care unit (ICU). MATERIALS AND METHODS: Between June-July 2019, a survey was electronically distributed to 11 centers. The survey addressed: CAR products, toxicities, targeted treatments, management practices and interventions in the ICU. RESULTS: Most centers (82%) had experience with commercial and non-FDA approved CAR products. Criteria for ICU admission varied between centers for patients with Cytokine Release Syndrome (CRS) but were similar for Immune Effector Cell Associated Neurotoxicity Syndrome (ICANS). Practices for vasopressor support, neurotoxicity and electroencephalogram monitoring, use of prophylactic anti-epileptic drugs and tocilizumab were comparable. In contrast, fluid resuscitation, respiratory support, methods of surveillance and management of cerebral edema, use of corticosteroid and other anti-cytokine therapies varied between centers. CONCLUSIONS: This survey identified areas of investigation that could improve outcomes in CAR T-cell recipients such as fluid and vasopressor selection in CRS, management of respiratory failure, and less common complications such as hemophagocytic lymphohistiocytosis, infections and stroke. The variability in specific treatments for CAR T-cell toxicities, needs to be considered when designing future outcome studies of critically ill CAR T-cell patients.

Incidence, Predictors, and Outcomes of Failure of Noninvasive Ventilation in Acute Heart Failure Hospitalization.

BACKGROUND: Some patients with acute heart failure (AHF) who are treated initially with noninvasive ventilation (NIV) will require endotracheal intubation, which indicates NIV failure. The incidence and prognosis of NIV failure in patients with AHF are not well characterized. METHODS: Using the National In-Patient Sample (NIS), we conducted a retrospective cohort study of subjects hospitalized with AHF between 2008 and 2014 who were treated with NIV within 24 h of hospital admission. We determined predictors of NIV failure and determined the association between NIV failure and in-hospital mortality using Cox proportional hazard models. RESULTS: Of 279,534 subjects hospitalized with AHF and treated with NIV, 4,257 (1.52%) failed NIV and required intubation. Cardiogenic shock (odds ratio 8.79, 95% CI 6.89-11.2) and in-hospital arrest (odds ratio 24.9, 95% CI 18.71-33.14) were associated with NIV failure. In-hospital mortality was 26.5% for NIV failure compared to 5.6% for those without NIV (P < .001). After adjustment for demographics, comorbidities, cardiogenic shock, and in-hospital arrest, NIV failure was associated with nearly a 2-fold risk of in-hospital mortality (odds ratio 1.95, 95% CI 1.59-2.40). CONCLUSIONS: Intubation after initial NIV treatment was required in 1.5% of subjects hospitalized with AHF and treated with NIV, and was associated with high in-hospital mortality. These findings can guide future prospective interventional trials and quality improvement ventures.

ATS Core Curriculum 2020. Adult Critical Care Medicine.

The American Thoracic Society Core Curriculum updates clinicians annually in adult and pediatric pulmonary disease, medical critical care, and sleep medicine, in a 3- to 4-year recurring cycle of topics. These topics will be presented at the 2020 International Conference. Below is the adult critical care medicine core including complications of chemotherapy, acute-on-chronic liver failure, alcohol withdrawal syndrome, mechanical circulatory support, direct oral anticoagulants, upper gastrointestinal hemorrhage, and vasopressor selection.

Performance of Critical Care Outcome Prediction Models in an Intermediate Care Unit.

BACKGROUND: Intermediate care units (IMCUs) are heterogeneous in design and operation, which makes comparative effectiveness studies challenging. A generalizable outcome prediction model could improve such comparisons. However, little is known about the performance of critical care outcome prediction models in the intermediate care setting. The purpose of this study is to evaluate the performance of the Acute Physiology and Chronic Health Evaluation version II (APACHE II), Simplified Acute Physiology Score version II (SAPS II) and version 3 (SAPS 3), and Mortality Probability Model version III (MPM0III) in patients admitted to a well-characterized IMCU. MATERIALS AND METHODS: In the IMCU of an academic medical center (July to December 2012), the discrimination and calibration of each outcome prediction model were evaluated using the area under the receiver-operating characteristic and Hosmer-Lemeshow goodness-of-fit test, respectively. Standardized mortality ratios (SMRs) were also calculated. RESULTS: The cohort included data from 628 unique IMCU admissions with an inpatient mortality rate of 8.3%. All models exhibited good discrimination, but only the SAPS II and MPM0III were well calibrated. While the APACHE II and SAPS 3 both markedly overestimated mortality, the SMR for the SAPS II and MPM0III were 0.91 and 0.91, respectively. CONCLUSIONS: The SAPS II and MPM0III exhibited good discrimination and calibration, with slight overestimation of mortality. Each model should be further evaluated in multicenter studies of patients in the intermediate care setting.

PEEP Titration to Minimize Driving Pressure in Subjects With ARDS: A Prospective Physiological Study.

BACKGROUND: Observational studies report that lower driving pressure (ie, the difference between plateau pressure and PEEP) is associated with improved survival in patients with ARDS and may be a key mediator of lung-protective ventilation strategies. The primary objective of this study was to characterize reductions in driving pressure that could be achieved through changes in PEEP. METHODS: In this prospective physiological pilot study, 10 subjects with ARDS were placed on PEEP according to the ARDS Network Lower PEEP/FIO2 Table. PEEP was adjusted in small increments and decrements above and below this initial PEEP, and driving pressure was measured at each PEEP level. Subsequently, PEEP was set at the level resulting in the lowest driving pressure, and driving pressure was measured after 1, 5, 15, and 30 min to assess stability over time at constant PEEP. RESULTS: All subjects had ARDS with a median (interquartile range [IQR]) PaO2 /FIO2 of 116 (98-132) at enrollment. Median (IQR) driving pressure at baseline was 14 (13-17) cm H2O. After PEEP titration, median driving pressure decreased to 13 (12-14) cm H2O. The largest reduction in driving pressure was 4 cm H2O. Two subjects had no change in driving pressure at multiple PEEP levels. To achieve the lowest driving pressure, final PEEP was increased in 6 subjects and decreased in 4 subjects from the baseline PEEP prescribed by the ARDS Network Lower PEEP/FIO2 Table. Driving pressure reached equilibrium within 1-5 min and remained stable for 30 min following PEEP titration. CONCLUSIONS: PEEP titration had a variable effect in changing driving pressure across this small sample of ARDS subjects. In some subjects, PEEP was decreased from values given in the ARDS Network Lower PEEP/FIO2 Table to minimize driving pressure. Changes in driving pressure stabilized within a few minutes of PEEP titration.