Effect of lung volume preservation during spontaneous breathing trial on successful extubation in patients receiving mechanical ventilation: protocol for a multicenter clinical trial.

BACKGROUND: In standard weaning from mechanical ventilation, a successful spontaneous breathing test (SBT) consisting of 30 min 8 cmH2O pressure-support ventilation (PSV8) without positive end-expiratory pressure (PEEP) is followed by extubation with continuous suctioning; however, these practices might promote derecruitment. Evidence supports the feasibility and safety of extubation without suctioning. Ultrasound can assess lung aeration and respiratory muscles. We hypothesize that weaning aiming to preserve lung volume can yield higher rates of successful extubation. METHODS: This multicenter superiority trial will randomly assign eligible patients to receive either standard weaning [SBT: 30-min PSV8 without PEEP followed by extubation with continuous suctioning] or lung-volume-preservation weaning [SBT: 30-min PSV8 + 5 cmH2O PEEP followed by extubation with positive pressure without suctioning]. We will compare the rates of successful extubation and reintubation, ICU and hospital stays, and ultrasound measurements of the volume of aerated lung (modified lung ultrasound score), diaphragm and intercostal muscle thickness, and thickening fraction before and after successful or failed SBT. Patients will be followed for 90 days after randomization. DISCUSSION: We aim to recruit a large sample of representative patients (N = 1600). Our study cannot elucidate the specific effects of PEEP during SBT and of positive pressure during extubation; the results will show the joint effects derived from the synergy of these two factors. Although universal ultrasound monitoring of lungs, diaphragm, and intercostal muscles throughout weaning is unfeasible, if derecruitment is a major cause of weaning failure, ultrasound may help clinicians decide about extubation in high-risk and borderline patients. TRIAL REGISTRATION: The Research Ethics Committee (CEIm) of the Fundació Unió Catalana d'Hospitals approved the study (CEI 22/67 and 23/26). Registered at ClinicalTrials.gov in August 2023. Identifier: NCT05526053.

Relationship between volume and survival in closed intensive care units is weak and apparent only in mechanically ventilated patients.

BACKGROUND: Recent studies have found an association between increased volume and increased intensive care unit (ICU) survival; however, this association might not hold true in ICUs with permanent intensivist coverage. Our objective was to determine whether ICU volume correlates with survival in the Spanish healthcare system. METHODS: Post hoc analysis of a prospective study of all patients admitted to 29 ICUs during 3 months. At ICU discharge, the authors recorded demographic variables, severity score, and specific ICU treatments. Follow-up variables included ICU readmission and hospital mortality. Statistics include logistic multivariate analyses for hospital mortality according to quartiles of volume of patients. RESULTS: The authors studied 4,001 patients with a mean predicted risk of death of 23% (range at hospital level: 14-46%). Observed hospital mortality was 19% (range at hospital level: 11-35%), resulting in a standardized mortality ratio of 0.81 (range: 0.5-1.3). Among the 1,923 patients needing mechanical ventilation, the predicted risk of death was 32% (14-60%) and observed hospital mortality was 30% (12-61%), resulting in a standardized mortality ratio of 0.96 (0.5-1.7). The authors found no correlation between standardized mortality ratio and ICU volume in the entire population or in mechanically ventilated patients. Only mechanically ventilated patients in very low-volume ICUs had slightly worse outcome. CONCLUSION: In the currently studied healthcare system characterized by 24/7 intensivist coverage, the authors found wide variability in outcome among ICUs even after adjusting for severity of illness but no relationship between ICU volume and outcome. Only mechanically ventilated patients in very low-volume centers had slightly worse outcomes.

Limitation of life support techniques at admission to the intensive care unit: a multicenter prospective cohort study.

PURPOSE: To determine the frequency of limitations on life support techniques (LLSTs) on admission to intensive care units (ICU), factors associated, and 30-day survival in patients with LLST on ICU admission. METHODS: This prospective observational study included all patients admitted to 39 ICUs in a 45-day period in 2011. We recorded hospitals' characteristics (availability of intermediate care units, usual availability of ICU beds, and financial model) and patients' characteristics (demographics, reason for admission, functional status, risk of death, and LLST on ICU admission (withholding/withdrawing; specific techniques affected)). The primary outcome was 30-day survival for patients with LLST on ICU admission. Statistical analysis included multilevel logistic regression models. RESULTS: We recruited 3042 patients (age 62.5 ± 16.1 years). Most ICUs (94.8%) admitted patients with LLST, but only 238 (7.8% [95% CI 7.0-8.8]) patients had LLST on ICU admission; this group had higher ICU mortality (44.5 vs. 9.4% in patients without LLST; p < 0.001). Multilevel logistic regression showed a contextual effect of the hospital in LLST on ICU admission (median OR = 2.30 [95% CI 1.59-2.96]) and identified the following patient-related variables as independent factors associated with LLST on ICU admission: age, reason for admission, risk of death, and functional status. In patients with LLST on ICU admission, 30-day survival was 38% (95% CI 31.7-44.5). Factors associated with survival were age, reason for admission, risk of death, and number of reasons for LLST on ICU admission. CONCLUSIONS: The frequency of ICU admission with LLST is low but probably increasing; nearly one third of these patients survive for ≥ 30 days.

Reconnection to mechanical ventilation for 1 h after a successful spontaneous breathing trial reduces reintubation in critically ill patients: a multicenter randomized controlled trial.

BACKGROUND: Spontaneous breathing trials (SBT) can be exhausting, but the preventive role of rest has never been studied. This study aimed to evaluate whether reconnection to mechanical ventilation (MV) for 1 h after the effort of a successful SBT could reduce the need for reintubation in critically ill patients. METHODS: Randomized multicenter trial conducted in 17 Spanish medical-surgical intensive care units (Oct 2013-Jan 2015). Patients under MV for longer than 12 h who fulfilled criteria for planned extubation were randomly allocated after a successful SBT to direct extubation (control group) or reconnection to the ventilator for a 1-h rest before extubation (rest group). The primary outcome was reintubation within 48 h. Analysis was by intention to treat. RESULTS: We recruited 243 patients randomized to the control group and 227 to the rest group. Median time from intubation to SBT did not differ between groups [5.5 (2.7, 9.6) days in the control group vs. 5.7 (2.7, 10.6) in the rest group; p = 0.85]. Reintubation within 48 h after extubation was more common in the control than in the rest group [35 (14%) vs. 12 (5%) patients; OR 0.33; 95% CI 0.16-0.65; p < 0.001]. A multivariable regression model demonstrated that the variables independently associated with reintubation were rest [OR 0.34 (95%CI 0.17-0.68)], APACHE II [OR 1.04 (1.002-1.077)], and days of MV before SBT [OR 1.04 (1.001-1.073)], whereas age, reason for admission, and type and duration of SBT were not. CONCLUSION: One-hour rest after a successful SBT reduced the rates of reintubation within 48 h after extubation in critically ill patients. Trial registration Clinicaltrials.gov identifier NCT01915563.