Daily Anesthesiology Research Analysis
Three practice-informing studies stood out in anesthesiology and critical care. A large stepped-wedge cluster RCT showed that targeting normoxemia (SpO2 90–96%) in trauma ICU patients safely reduced hyperoxemia and sped weaning to room air without increasing hypoxemia. An ICU randomized trial found a flexible-tip bougie markedly improved first-attempt success for tracheal intubation with a hyperangulated videolaryngoscope versus a stylet. A multicenter cohort linked higher early mechanical power
Summary
Three practice-informing studies stood out in anesthesiology and critical care. A large stepped-wedge cluster RCT showed that targeting normoxemia (SpO2 90–96%) in trauma ICU patients safely reduced hyperoxemia and sped weaning to room air without increasing hypoxemia. An ICU randomized trial found a flexible-tip bougie markedly improved first-attempt success for tracheal intubation with a hyperangulated videolaryngoscope versus a stylet. A multicenter cohort linked higher early mechanical power during ventilation to higher ICU mortality in acute hypoxemic respiratory failure, with no safe threshold.
Research Themes
- Oxygen stewardship and normoxemia targeting in critical care
- Airway device optimization for ICU videolaryngoscopy
- Ventilator-induced lung injury metrics (mechanical power) and outcomes
Selected Articles
1. Targeted Normoxemia and Supplemental Oxygen-Free Days in Critically Injured Adults: A Stepped-Wedge Cluster Randomized Clinical Trial.
In this multicenter stepped-wedge cluster RCT (N=12,487), targeting SpO2 90–96% increased time in normoxemia, reduced hyperoxemia, and did not increase hypoxemia. Although supplemental oxygen–free days were not improved overall, time to room air was shorter and a prespecified subgroup (not ventilated at ICU admission) had slightly more oxygen-free days.
Impact: This pragmatic trial provides high-level evidence to guide oxygen stewardship in the ICU, showing clinicians can safely reduce hyperoxemia by targeting normoxemia without increasing hypoxemia.
Clinical Implications: Adopt SpO2 targets of 90–96% for critically injured adults to reduce hyperoxemia and expedite weaning to room air, with monitoring to avoid hypoxemia. Expect neutral effect on overall oxygen-free days but process-of-care gains.
Key Findings
- Normoxemia time increased from 56.2% to 71.6%; hyperoxemia decreased from 42.4% to 26.7%; hypoxemia remained 1.1% in both groups.
- No overall increase in supplemental oxygen–free days (adjusted mean difference 0.32 days; 95% CI -0.37 to 1.00; P=0.30).
- Faster weaning to room air (adjusted hazard ratio 1.23; 95% CI 1.13–1.33) without safety signal; mortality to day 90 similar.
- Among patients not ventilated at ICU admission, oxygen-free days modestly improved (AMD 0.75 days; 95% CI 0.00–1.50).
Methodological Strengths
- Multicenter stepped-wedge cluster randomized design with intention-to-treat analysis
- Large sample size (N=12,487) and pragmatic, process-integrated intervention
Limitations
- Primary outcome was neutral overall; potential contamination and secular trends inherent to stepped-wedge designs
- Unblinded process intervention; conducted in US level I trauma centers, potentially limiting generalizability
Future Directions: Test normoxemia-targeting bundles in broader ICU populations, assess patient-centered outcomes and cost-effectiveness, and integrate automated closed-loop oxygen control.
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.
2. Flexible-tip bougie vs. stylet for tracheal intubation with a hyperangulated videolaryngoscope in critical care: a randomised controlled trial.
In ICU intubations using a hyperangulated videolaryngoscope, a flexible-tip bougie achieved a 99% first-attempt success rate versus 83% with a stylet, with less need for laryngeal manipulation and no increase in complications.
Impact: Clear, clinically meaningful improvement in first-pass success supports changing default introducer choice for hyperangulated videolaryngoscopy in critical care.
Clinical Implications: Prefer a flexible-tip bougie rather than a stylet when using hyperangulated videolaryngoscopes in ICU to maximize first-pass success and minimize adjunct maneuvers.
Key Findings
- First-attempt success: 99% (flexible-tip bougie) vs 83% (stylet), P=0.005.
- Fewer laryngeal manipulations with bougie: 10% vs 31.4%.
- No significant difference in complication rates between techniques.
- Operator-rated difficulty favored bougie (not difficult/slightly difficult in 99% vs 90%).
Methodological Strengths
- Randomized controlled design with clinically relevant ICU population
- Clear, objective primary endpoint (first-attempt success) and standardized device context (hyperangulated blade)
Limitations
- Single-center trial and lack of blinding of operators
- Results limited to hyperangulated videolaryngoscopes; generalizability to standard blades uncertain
Future Directions: Validate findings across multiple centers, operator experience levels, and different hyperangulated platforms; assess effects on hypoxemia and hemodynamic instability.
INTRODUCTION: The optimal introducer for tracheal intubation with a hyperangulated blade videolaryngoscope for patients in the ICU remains uncertain. Both stylets and flexible-tip bougies have been used, yet there is limited evidence on which is more efficacious. METHODS: We conducted a randomised controlled trial comparing flexible-tip bougie vs. stylet using a hyperangulated blade videolaryngoscope (C-MAC RESULTS: A total of 140 patients were allocated randomly (40 female (29%); mean (SD) age 68 (13.0) y). First-attempt tracheal intubation success was higher in patients allocated to flexible-tip bougie (69/70, 99%) compared with stylet (58/70 (83%), p = 0.005). The proportion of patients' tracheas intubated in one, two or three attempts was 69/70 (99%), 1/70 (1%) and 0/70 (0%) in the flexible-tip bougie group, compared with 58/70 (83%), 7/70 (10%), and 5/70 (7%) in the stylet group, respectively. More patients in the stylet group required laryngeal manipulation (22/70 (31.4%)) during tracheal intubation compared with the flexible-tip group (7/70 (10%)). Anaesthetists rated 69/70 (99%) of tracheal intubations with the flexible-tip bougie as not difficult or slightly difficult compared with 63/70 (90%) for the stylet group. No significant difference in the incidence of complications was observed between the two techniques. DISCUSSION: In the ICU, first-attempt tracheal intubation success with a hyperangulated blade videolaryngoscope was higher using the flexible-tip bougie than the stylet. No differences were observed in operator difficulty or complication rates between the two techniques.
3. The Association Between Mechanical Power Within the First 24 Hours and ICU Mortality in Mechanically Ventilated Adult Patients With Acute Hypoxemic Respiratory Failure: A Registry-Based Cohort Study.
Across 9,031 mechanically ventilated adults with acute hypoxemic respiratory failure, higher mechanical power within the first 24 hours was independently associated with higher ICU mortality (OR 1.58), fewer ventilator-free days, and lower extubation rates, with no safe threshold identified.
Impact: Mechanical power is a synthesizing metric of injurious ventilation. Quantifying its association with mortality in a broad AHRF cohort supports MP minimization as a target for future interventional trials.
Clinical Implications: Consider incorporating mechanical power into bedside ventilator management and aim to minimize MP early (e.g., by optimizing VT, RR, Pplat/PEEP) alongside conventional lung-protective strategies.
Key Findings
- High mechanical power (>17 J/min) in the first 24 hours was associated with higher ICU mortality (adjusted OR 1.58; 95% CI 1.44–1.72).
- Nonlinear dose-response relationship observed; no consistent safe threshold of mechanical power identified.
- High MP was linked to lower extubation rates and fewer ventilator-free days.
Methodological Strengths
- Large multicenter registry with 9,031 eligible AHRF patients and robust adjustment (IPTW, spline models)
- Predefined exposure window (first 24 hours) aligning with actionable ventilator management
Limitations
- Observational design with residual confounding; mechanical power components may reflect severity and clinician choices
- Modeling relies on dynamic driving pressure; generalizability to all ventilator modes requires caution
Future Directions: Randomized trials testing mechanical power–targeted ventilation strategies and evaluating causal effects on mortality and VILI biomarkers.
BACKGROUND: Despite the widespread adoption of lung-protective ventilation strategies, mortality among patients receiving invasive mechanical ventilation (IMV) remains high. Mechanical power (MP) integrates various variables responsible for ventilator-induced lung injury and has been associated with mortality in patients with ARDS. However, the impact of MP on ICU mortality in the larger group of patients with acute hypoxemic respiratory failure (AHRF) has not been well established, and previous studies have reported inconsistent thresholds for predicting outcomes. RESEARCH QUESTION: Is high MP (> 17 J/min) within the first 24 hours of IMV, calculated using dynamic driving pressure, associated with ICU mortality in patients with AHRF? Additionally, does a threshold exist below which IMV is considered safe? STUDY DESIGN AND METHODS: In this multicenter cohort study, we included adult patients with AHRF who received IMV. Patients were excluded if they received IMV for > 24 hours before inclusion or were receiving extracorporeal life support. We applied multivariable logistic regression models with inverse probability of treatment weighting and used change-point regression models with restricted cubic splines. RESULTS: Of the 21,714 patients in our registry, 9,031 patients (42%) met the inclusion criteria. After adjusting for baseline characteristics, high MP was associated with increased ICU mortality (OR, 1.58; 95% CI, 1.44-1.72), with a nonlinear dose-response relationship. No consistent safe MP threshold was identified. High MP also was associated with lower extubation rates and fewer ventilator-free days. INTERPRETATION: In this study, exposure to high MP within the first 24 hours of IMV was associated with increased ICU mortality in patients with AHRF. The absence of a consistent safe threshold suggests that reducing MP at IMV initiation may be a strategy to improve outcomes, warranting exploration in clinical trials.