A multicenter cluster randomized, stepped wedge implementation trial for targeted normoxia in critically ill trauma patients: study protocol and statistical analysis plan for the Strategy to Avoid Excessive Oxygen (SAVE-O2) trial

Targeted Normoxemia and Supplemental Oxygen-Free Days in Critically Injured Adults: A Stepped-Wedge Cluster Randomized Clinical Trial

Importance

Supplemental oxygen is fundamental to caring for critically injured adults but can expose them to excess inspired oxygen.

Objective

To determine the safety and effectiveness of targeting normoxemia in critically ill trauma patients.

Design, Setting, and Participants

This multicenter, stepped-wedge, cluster randomized clinical trial compared targeted normoxemia (defined as a peripheral oxygen saturation [Spo2] of 90% to 96%) with usual care among adult trauma patients admitted to an intensive care unit (ICU) at 8 level I trauma centers across the US. These trauma centers were randomized at 3-month intervals when they crossed over from usual care to targeting normoxemia. Eligible patients were enrolled between July 15, 2020, and November 14, 2022. All statistical analyses were performed from April 2023 to November 2024 according to intention-to-treat approach.

Intervention

In the usual care group, supplemental oxygen was determined by treating clinicians. In the targeted normoxemia group, a multimodal educational and informatics intervention encouraged decreasing the supplemental oxygen administered whenever Spo2 exceeded 96%.

Main Outcomes and Measures

The primary outcome was supplemental oxygen-free days (SOFDs), defined as the number of days alive and not receiving supplemental oxygen through day 28. Safety outcomes included hypoxemia (defined as Spo2 <88%) during the ICU admission, in-hospital mortality, and adverse events.

Results

A total of 12 487 patients were enrolled (mean [SD] age, 51.7 [21.1] years; 8799 males [70.5%]; mean [SD] Injury Severity Score, 19.6 [12.0]). The proportion of ICU time spent in normoxemia increased from 56.2% in the usual care group to 71.6% in the targeted normoxemia group. Hyperoxemia (defined as Spo2 >96%) decreased from 42.4% in the usual care group to 26.7% in the targeted normoxemia group, and hypoxemia was similar between groups (1.1% vs 1.1%). The raw mean (SD) number of SOFDs was 19.6 (10.3) days for the targeted normoxemia group and 17.5 (10.4) days for the usual care group (adjusted mean difference [AMD], 0.32 [95% CI, -0.37 to 1.00] days; P = .30). Among patients not receiving mechanical ventilation at ICU admission, mean SOFDs were greater in the targeted normoxemia group than in the usual care group (22.6 [8.30] days vs 20.6 [8.86] days; AMD, 0.75; 95% CI, 0.00-1.50 days). The mean (SD) time for weaning to room air was 1.6 (3.2) days for the targeted normoxemia group and 2.7 (4.0) days for the usual care group (adjusted hazard ratio [AHR], 1.23; 95% CI, 1.13-1.33 days). In-hospital mortality to day 90 occurred in 563 patients (9.9%) in the targeted normoxemia and 732 patients (10.7%) in the usual care group (AHR, 1.05; 95% CI, 0.83-1.33). No adverse events were reported in either group.

Conclusions and Relevance

This randomized clinical trial showed that targeting normoxemia did not increase the number of SOFDs but safely reduced supplemental oxygen use among critically ill trauma patients.

Trial Registration

ClinicalTrials.gov Identifier: NCT04534959.

Impact of En Route Critical Care Provider Experience on Lung Protective Ventilation Compliance During Air Transport of Combat Wounded

INTRODUCTION

The primary objective of this study was to evaluate the association between the U.S. Air Force Critical Care Air Transport (CCAT) provider operational experience with compliance for lung protective ventilation (LPV) volumes recommended by Acute Respiratory Distress Syndrome Clinical Network guidelines.

MATERIALS AND METHODS

We performed a retrospective cohort study of CCAT providers transporting combat casualties requiring mechanical ventilation from the Middle East to Germany from 2007 to 2012. We reviewed CCAT medical records from 2007 to 2012 for the total number of patient transports by CCAT physicians and respiratory care practitioners (RCPs). Center for Sustainment of Trauma and Readiness Skills Cincinnati process improvement questionnaire data described provider demographics and clinical backgrounds. We linked these data to patient demographics and in-flight ventilation management from a prior CCAT cohort study. Patient inclusion criteria included transport by CCAT from the Middle East to Germany for traumatic injury requiring mechanical ventilation between 2007 and 2012. We excluded patients with no documented height or tidal volume. LPV compliance was defined as tidal volumes ≤8 mL/kg of predicted body weight during en route critical care transport. We performed a logistic regression analysis. This study was reviewed and approved by the 59th Medical Wing institutional review board (IRB).

RESULTS

We analyzed 491 patient transports conducted by 71 (RCPs and 84 physicians. Patients had a median age of 25 years (IQR 22-30), 98% were male, median injury severity score was 24 (IQR 17-34), and median preflight PaO2/FiO2 was 285 (IQR 220-365). Median experience was 26 missions (IQR 13-40) for RCPs and 23 missions (IQR 12-38) for physicians. All in-flight tidal volumes were LPV compliant in 58.3% of missions. Unadjusted analysis showed higher LPV compliance for RCPs with in-garrison critical care experience. Multivariate models did not find an association between missions flown and LPV compliance but did demonstrate a positive association with physician specialty of medical intensivist (OR 3.0, 95% CI 1.6-5.7) and a negative association with flights in 2008 (OR 0.4, 95% CI 0.2-0.7) for LPV compliance.

CONCLUSION

No association was found between number of missions flown by CCAT providers and lung protective tidal volume compliance. Linkage of multiple data sources enabled investigation of clinical and operational currency associations with a care quality metric compliance in the combat en route care environment. Future studies should evaluate the impact of ongoing CCAT training and quality improvement interventions on LPV compliance.

Nebulized Furosemide for Pulmonary Inflammation in Intubated Patients With COVID-19: A Phase 2 Randomized Controlled Double-Blind Study

OBJECTIVES

Respiratory failure secondary to COVID-19 is associated with morbidity and mortality. Current anti-inflammatory therapies are effective but are given systemically and have significant side effects. Furosemide has anti-inflammatory properties, can be administered by inhalation, and is inexpensive. We investigated the efficacy of nebulized furosemide as an adjunctive therapy for COVID-19 respiratory failure.

DESIGN

A double-blind, randomized, placebo-controlled trial.

SETTING

Multicenter ICU study.

PATIENTS

Adults requiring invasive mechanical ventilation secondary to COVID-19.

INTERVENTION

Patients were randomized within 48 hours of intubation to receive inhaled furosemide or placebo until day 28, death, or liberation from mechanical ventilation.

MEASUREMENTS AND MAIN RESULTS

The study was stopped early due to waning incidence of COVID-19; 39 patients were available for analysis with mean ± sd age of 70.5 (10.8) years, Acute Physiology and Chronic Health Evaluation II 26.1 (7.8) and Fio2 60.0% (21.9). Baseline characteristics were similar between the groups. For the primary outcome of change in Pao2/Fio2 ratio between day 1 and day 6, it was +31.4 (83.5) in the furosemide arm versus +20.1 (92.8) in the control (p = 0.58). For secondary outcomes, furosemide versus control: 60-day mortality was 48% versus 71% (p = 0.20), hospital stay was 25.6 (21.9) versus 27.4 (25.0) days, p = 0.94 and VFD was 6.0 (9.1) versus 3.1 (7.1), p value of equals to 0.28. A post hoc analysis of the hierarchical composite outcome, alive and ventilator-free favored furosemide. There were no adverse events.

CONCLUSIONS

In this trial of inhaled furosemide for COVID-19 respiratory failure, differences in Pao2/Fio2 ratio to day 6 and other clinical outcomes were not significantly different, although the trial was underpowered due to early termination. Given the favorable profile of inhaled furosemide, further study is warranted in disease states where acute pulmonary inflammation contributes to the underlying pathophysiology.

Provider Perceptions of Oxygenation Strategies for Critically Ill Trauma Patients With and Without Moderate-to-Severe Traumatic Brain Injury

BACKGROUND

Hypoxia and hyperoxia (pulse oximetry [SpO2] > 96%) are associated with increased mortality in critically ill patients. However, provider practices regarding oxygenation in traumatic brain injury (TBI) patients are unknown. This study assesses views on oxygenation of critically ill trauma patients with and without TBI and how this varies between Neurological ICU (NeuroICU) and Surgical-Trauma ICU (STICU) providers.

METHODS

This is a cross-sectional survey of Level I trauma center's NeuroICU and STICU providers. We used Likert scales, yes-no questions, and multiple-choice case-based scenarios to characterize provider views on oxygenation with descriptive statistics to characterize responses. Significant differences regarding TBI and non-TBI patients or NeuroICU and STICU providers were determined using Fisher's exact test and a P-value of .05.

RESULTS

A total of 83 providers initiated the survey, and 53 providers completed it. Most providers identified a threshold SpO2 < 92% for the administration of supplemental oxygen in critically ill TBI patients. A total of 9% of providers "somewhat or completely agreed" that they were more likely to give supplemental oxygen to a critically ill trauma patient with TBI than one without TBI and the same SpO2. A total of 48% of providers selected an SpO2 < 90% as the point at which supplemental oxygen should be initiated in patients without TBI, compared to 27% of providers in patients with TBI (P < .01). This threshold for supplemental oxygen use varied by provider type for non-TBI patients, but not for TBI patients (30% NeuroICU and 69% STICU providers selected SpO2 < 90% in non-TBI, P < .05; 30% NeuroICU and 35% STICU providers selected SpO2 < 90% in TBI, P = .85).

CONCLUSIONS

Critical care providers at UCHealth University of Colorado Hospital approach the oxygenation of critically ill trauma patients with and without TBI differently. Specifically, critical care respondents accepted a different lower oxygen saturation threshold for TBI and non-TBI patients. NeuroICU and STICU respondents differed in their threshold for the down-titration of supplemental oxygen. Targeted education for critical care providers may reduce these discrepancies and optimize oxygen use.

Hyperoxia is associated with a greater risk for mortality in critically ill traumatic brain injury patients than in critically ill trauma patients without brain injury

OBJECTIVE

The role of hyperoxia in patients with traumatic brain injury (TBI) remains controversial. The objective of this study was to determine the association between hyperoxia and mortality in critically ill TBI patients compared to critically ill trauma patients without TBI.

DESIGN

Secondary analysis of a multicenter retrospective cohort study.

SETTING

Three regional trauma centers in Colorado, USA, between October 1, 2015, and June 30, 2018.

PATIENTS

We included 3464 critically injured adults who were admitted to an intensive care unit (ICU) within 24 h of arrival and qualified for inclusion into the state trauma registry. We analyzed all available SpO2 values during the first seven ICU days. The primary outcome was in-hospital mortality. Secondary outcomes included the proportion of time spent in hyperoxia (defined as SpO2 > 96%) and ventilator-free days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

In-hospital mortality occurred in 163 patients (10.7%) in the TBI group and 101 patients (5.2%) in the non-TBI group. After adjusting for ICU length of stay, TBI patients spent a significantly greater amount of time in hyperoxia versus non-TBI patients (p = 0.024). TBI status significantly modified the effect of hyperoxia on mortality. At each specific SpO2 level, the risk of mortality increases with increasing FiO2 for both patients with and without TBI. This trend was more pronounced at lower FiO2 and higher SpO2 values, where a greater number of patient observations were obtained. Among patients who required invasive mechanical ventilation, TBI patients required significantly more days of ventilation to day 28 than non-TBI patients.

CONCLUSIONS

Critically ill trauma patients with a TBI spend a greater proportion of time in hyperoxia compared to those without a TBI. TBI status significantly modified the effect of hyperoxia on mortality. Prospective clinical trials are needed to better assess a possible causal relationship.

Oxygen-Free Days as an Outcome Measure in Clinical Trials of Therapies for COVID-19 and Other Causes of New-Onset Hypoxemia

Mortality historically has been the primary outcome of choice for acute and critical care clinical trials. However, undue reliance on mortality can limit the scope of trials that can be performed. Large sample sizes are usually needed for trials powered for a mortality outcome, and focusing solely on mortality fails to recognize the importance that reducing morbidity can have on patients' lives. The COVID-19 pandemic has highlighted the need for rapid, efficient trials to rigorously evaluate new therapies for hospitalized patients with acute lung injury. Oxygen-free days (OFDs) is a novel outcome for clinical trials that is a composite of mortality and duration of new supplemental oxygen use. It is designed to characterize recovery from acute lung injury in populations with a high prevalence of new hypoxemia and supplemental oxygen use. In these populations, OFDs captures two patient-centered consequences of acute lung injury: mortality and hypoxemic lung dysfunction. Power to detect differences in OFDs typically is greater than that for other clinical trial outcomes, such as mortality and ventilator-free days. OFDs is the primary outcome for the Fourth Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV-4) Host Tissue platform, which evaluates novel therapies targeting the host response to COVID-19 among adults hospitalized with COVID-19 and new hypoxemia. This article outlines the rationale for use of OFDs as an outcome for clinical trials, proposes a standardized method for defining and analyzing OFDs, and provides a framework for sample size calculations using the OFD outcome.