Timing of Intubation in Acute Respiratory Failure Associated With Sepsis: A Mixed Methods Study

Impact of the timing of invasive mechanical ventilation in patients with sepsis: a multicenter cohort study

BACKGROUND

The potential adverse effects associated with invasive mechanical ventilation (MV) can lead to delayed decisions on starting MV. We aimed to explore the association between the timing of MV and the clinical outcomes in patients with sepsis ventilated in intensive care unit (ICU).

METHODS

We analyzed data of adult patients with sepsis between September 2019 and December 2021. Data was collected through the Korean Sepsis Alliance from 20 hospitals in Korea. Patients who were admitted to ICU and received MV were included in the study. Patients were divided into 'early MV' and 'delayed MV' groups based on whether they were on MV on the first day of ICU admission or later. Propensity score matching was applied, and patients in the two groups were compared on a 1:1 ratio to overcome bias between the groups. Outcomes including ICU mortality, hospital mortality, length of hospital and ICU stay, and organ failure at ICU discharge were compared.

RESULTS

Out of 2440 patients on MV during ICU stay, 2119 'early MV' and 321 'delayed MV' cases were analyzed. The propensity score matching identified 295 patients in each group with similar baseline characteristics. ICU mortality was lower in 'early MV' group than 'delayed MV' group (36.3% vs. 46.4%; odds ratio, 0.66; 95% confidence interval, 0.47-0.93; p = 0.015). 'Early MV' group had lower in-hospital mortality, shorter ICU stay, and required tracheostomy less frequently than 'delayed MV' group. Multivariable logistic regression model identified 'early MV' as associated with lower ICU mortality (odds ratio, 0.38; 95% confidence interval, 0.29-0.50; p < 0.001).

CONCLUSION

In patients with sepsis ventilated in ICU, earlier start (first day of ICU admission) of MV may be associated with lower mortality.

When to intubate in acute hypoxaemic respiratory failure? Options and opportunities for evidence-informed decision making in the intensive care unit

The optimal timing of intubation in acute hypoxaemic respiratory failure is uncertain and became a point of controversy during the COVID-19 pandemic. Invasive mechanical ventilation is a potentially life-saving intervention but carries substantial risks, including injury to the lungs and diaphragm, pneumonia, intensive care unit-acquired muscle weakness, and haemodynamic impairment. In deciding when to intubate, clinicians must balance premature exposure to the risks of ventilation with the potential harms of unassisted breathing, including disease progression and worsening multiorgan failure. Currently, the optimal timing of intubation is unclear. In this Personal View, we examine a range of parameters that could serve as triggers to initiate invasive mechanical ventilation. The utility of a parameter (eg, the ratio of arterial oxygen tension to fraction of inspired oxygen) to predict the likelihood of a patient undergoing intubation does not necessarily mean that basing the timing of intubation on that parameter will improve therapeutic outcomes. We examine options for clinical investigation to make progress on establishing the optimal timing of intubation.

Association between Patient Race and Ethnicity and Use of Invasive Ventilation in the United States

Rationale: Outcomes for people with respiratory failure in the United States vary by patient race and ethnicity. Invasive ventilation is an important treatment initiated based on expert opinion. It is unknown whether the use of invasive ventilation varies by patient race and ethnicity. Objectives: To measure 1) the association between patient race and ethnicity and the use of invasive ventilation; and 2) the change in 28-day mortality mediated by any association. Methods: We performed a multicenter cohort study of nonintubated adults receiving oxygen within 24 hours of intensive care admission using the Medical Information Mart for Intensive Care IV (MIMIC-IV, 2008-2019) and Phillips eICU (eICU, 2014-2015) databases from the United States. We modeled the association between patient race and ethnicity (Asian, Black, Hispanic, White) and invasive ventilation rate using a Bayesian multistate model that adjusted for baseline and time-varying covariates, calculated hazard ratios (HRs), and estimated 28-day hospital mortality changes mediated by differential invasive ventilation use. We reported posterior means and 95% credible intervals (CrIs). Results: We studied 38,258 patients, 52% (20,032) from MIMIC-IV and 48% (18,226) from eICU: 2% Asian (892), 11% Black (4,289), 5% Hispanic (1,964), and 81% White (31,113). Invasive ventilation occurred in 9.2% (3,511), and 7.5% (2,869) died. The adjusted rate of invasive ventilation was lower in Asian (HR, 0.82; CrI, 0.70-0.95), Black (HR, 0.78; CrI, 0.71-0.86), and Hispanic (HR, 0.70; CrI, 0.61-0.79) patients compared with White patients. For the average patient, lower rates of invasive ventilation did not mediate differences in 28-day mortality. For a patient on high-flow nasal cannula with inspired oxygen fraction of 1.0, the odds ratios for mortality if invasive ventilation rates were equal to the rate for White patients were 0.97 (CrI, 0.91-1.03) for Asian patients, 0.96 (CrI, 0.91-1.03) for Black patients, and 0.94 (CrI, 0.89-1.01) for Hispanic patients. Conclusions: Asian, Black, and Hispanic patients had lower rates of invasive ventilation than White patients. These decreases did not mediate harm for the average patient, but we could not rule out harm for patients with more severe hypoxemia.

Timing of invasive mechanical ventilation and death in critically ill adults with COVID-19: A multicenter cohort study

PURPOSE

To investigate if the timing of initiation of invasive mechanical ventilation (IMV) for critically ill patients with COVID-19 is associated with mortality.

MATERIALS AND METHODS

The data for this study were derived from a multicenter cohort study of critically ill adults with COVID-19 admitted to ICUs at 68 hospitals across the US from March 1 to July 1, 2020. We examined the association between early (ICU days 1-2) versus late (ICU days 3-7) initiation of IMV and time-to-death. Patients were followed until the first of hospital discharge, death, or 90 days. We adjusted for confounding using a multivariable Cox model.

RESULTS

Among the 1879 patients included in this analysis (1199 male [63.8%]; median age, 63 [IQR, 53-72] years), 1526 (81.2%) initiated IMV early and 353 (18.8%) initiated IMV late. A total of 644 of the 1526 patients (42.2%) in the early IMV group died, and 180 of the 353 (51.0%) in the late IMV group died (adjusted HR 0.77 [95% CI, 0.65-0.93]).

CONCLUSIONS

In critically ill adults with respiratory failure from COVID-19, early compared to late initiation of IMV is associated with reduced mortality.

Radiologic Assessment of Lung Edema Score as a Predictor of Clinical Outcome in Children with Acute Respiratory Distress Syndrome

PURPOSE

The radiographic assessment of lung edema (RALE) score enables objective quantification of lung edema and is a valuable prognostic marker of adult acute respiratory distress syndrome (ARDS). We aimed to evaluate the validity of RALE score in children with ARDS.

MATERIALS AND METHODS

The RALE score was measured for its reliability and correlation to other ARDS severity indices. ARDS-specific mortality was defined as death from severe pulmonary dysfunction or the need for extracorporeal membrane oxygenation therapy. The C-index of the RALE score and other ARDS severity indices were compared via survival analyses.

RESULTS

Among 296 children with ARDS, 88 did not survive, and there were 70 ARDS-specific non-survivors. The RALE score showed good reliability with an intraclass correlation coefficient of 0.809 [95% confidence interval (CI), 0.760-0.848]. In univariable analysis, the RALE score had a hazard ratio (HR) of 1.19 (95% CI, 1.18-3.11), and the significance was maintained in multivariable analysis adjusting with age, ARDS etiology, and comorbidity, with an HR of 1.77 (95% CI, 1.05-2.91). The RALE score was a good predictor of ARDS-specific mortality, with a C-index of 0.607 (95% CI, 0.519-0.695).

CONCLUSION

The RALE score is a reliable measure for ARDS severity and a useful prognostic marker of mortality in children, especially for ARDS-specific mortality. This score provides information that clinicians can use to decide the proper time of aggressive therapy targeting severe lung injury and to appropriately manage the fluid balance of children with ARDS.

Oxygenation thresholds for invasive ventilation in hypoxemic respiratory failure: a target trial emulation in two cohorts

BACKGROUND

The optimal thresholds for the initiation of invasive ventilation in patients with hypoxemic respiratory failure are unknown. Using the saturation-to-inspired oxygen ratio (SF), we compared lower versus higher hypoxemia severity thresholds for initiating invasive ventilation.

METHODS

This target trial emulation included patients from the Medical Information Mart for Intensive Care (MIMIC-IV, 2008-2019) and the Amsterdam University Medical Centers (AmsterdamUMCdb, 2003-2016) databases admitted to intensive care and receiving inspired oxygen fraction ≥ 0.4 via non-rebreather mask, noninvasive ventilation, or high-flow nasal cannula. We compared the effect of using invasive ventilation initiation thresholds of SF < 110, < 98, and < 88 on 28-day mortality. MIMIC-IV was used for the primary analysis and AmsterdamUMCdb for the secondary analysis. We obtained posterior means and 95% credible intervals (CrI) with nonparametric Bayesian G-computation.

RESULTS

We studied 3,357 patients in the primary analysis. For invasive ventilation initiation thresholds SF < 110, SF < 98, and SF < 88, the predicted 28-day probabilities of invasive ventilation were 72%, 47%, and 19%. Predicted 28-day mortality was lowest with threshold SF < 110 (22.2%, CrI 19.2 to 25.0), compared to SF < 98 (absolute risk increase 1.6%, CrI 0.6 to 2.6) or SF < 88 (absolute risk increase 3.5%, CrI 1.4 to 5.4). In the secondary analysis (1,279 patients), the predicted 28-day probability of invasive ventilation was 50% for initiation threshold SF < 110, 28% for SF < 98, and 19% for SF < 88. In contrast with the primary analysis, predicted mortality was highest with threshold SF < 110 (14.6%, CrI 7.7 to 22.3), compared to SF < 98 (absolute risk decrease 0.5%, CrI 0.0 to 0.9) or SF < 88 (absolute risk decrease 1.9%, CrI 0.9 to 2.8).

CONCLUSION

Initiating invasive ventilation at lower hypoxemia severity will increase the rate of invasive ventilation, but this can either increase or decrease the expected mortality, with the direction of effect likely depending on baseline mortality risk and clinical context.

Do Thresholds for Invasive Ventilation in Hypoxemic Respiratory Failure Exist? A Cohort Study

Rationale: Invasive ventilation is a significant event for patients with respiratory failure. Physiologic thresholds standardize the use of invasive ventilation in clinical trials, but it is unknown whether thresholds prompt invasive ventilation in clinical practice. Objectives: To measure, in patients with hypoxemic respiratory failure, the probability of invasive ventilation within 3 hours after meeting physiologic thresholds. Methods: We studied patients admitted to intensive care receiving Fi_O2 of 0.4 or more via nonrebreather mask, noninvasive positive pressure ventilation, or high-flow nasal cannula, using data from the Medical Information Mart for Intensive Care (MIMIC)-IV database (2008-2019) and the Amsterdam University Medical Centers Database (AmsterdamUMCdb) (2003-2016). We evaluated 17 thresholds, including the ratio of arterial to inspired oxygen, the ratio of saturation to inspired oxygen ratio, composite scores, and criteria from randomized trials. We report the probability of invasive ventilation within 3 hours of meeting each threshold and its association with covariates using odds ratios (ORs) and 95% credible intervals (CrIs). Measurements and Main Results: We studied 4,726 patients (3,365 from MIMIC, 1,361 from AmsterdamUMCdb). Invasive ventilation occurred in 28% (1,320). In MIMIC, the highest probability of invasive ventilation within 3 hours of meeting a threshold was 20%, after meeting prespecified neurologic or respiratory criteria while on vasopressors, and 19%, after a ratio of arterial to inspired oxygen of <80 mm Hg. In AmsterdamUMCdb, the highest probability was 34%, after vasopressor initiation, and 25%, after a ratio of saturation to inspired oxygen of <90. The probability after meeting the threshold from randomized trials was 9% (MIMIC) and 13% (AmsterdamUMCdb). In MIMIC, a race/ethnicity of Black (OR, 0.75; 95% CrI, 0.57-0.96) or Asian (OR, 0.6; 95% CrI, 0.35-0.95) compared with White was associated with decreased probability of invasive ventilation after meeting a threshold. Conclusions: The probability of invasive ventilation within 3 hours of meeting physiologic thresholds was low and associated with patient race/ethnicity.

Ventilator avoidance among critically ill COVID-19 patients with acute respiratory distress syndrome

Objective

To determine the incidence and significance of ventilator avoidance in patients with critical coronavirus disease 2019 (COVID-19).

Methods

This prospective observational cohort study evaluated hospital mortality and 1-year functional outcome among critically ill patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-associated acute respiratory distress syndrome (ARDS). The explanatory variable was ventilator avoidance, modeled as ‘initial refusal’ of intubation (yes/no). Modified Rankin Scale (mRS) scores were obtained from surviving patients (or their surrogates) via phone or email questionnaire.

Results

Among patients for whom intubation was recommended (n = 102), 40 (39%) initially refused (95% confidence interval [CI] 30%, 49%). The risk of death was 79.3% (49/62) in those who did not initially refuse intubation compared with 77.5% (31/40) in those who initially refused, with an adjusted odds ratio for death of 1.27 (95% CI 0.47, 3.48). The distribution of 1-year mRS scores was not significantly different between groups.

Conclusion

Among critically ill patients with COVID-19-associated ARDS, ventilator avoidance was common, but was not associated with increased in-hospital mortality or 1-year functional outcome.

Association between timing of intubation and clinical outcomes of critically ill patients: A meta-analysis

PURPOSE

Optimal timing of intubation is controversial. We attempted to investigate the association between timing of intubation and clinical outcomes of critically ill patients.

METHODS

PubMed was systematically searched for studies reporting on mortality of critically ill patients undergoing early versus late intubation. Studies involving patients with new coronavirus disease (COVID-19) were excluded because a relevant meta-analysis has been published. "Early" intubation was defined according to the authors of the included studies. All-cause mortality was the primary outcome. Pooled risk ratio (RR) and 95% confidence intervals (CI) were calculated using a random effects model. The meta-analysis was registered with PROSPERO (CRD42021284850).

RESULTS

In total, 27 studies involving 15,441 intubated patients (11,943 early, 3498 late) were included. All-cause mortality was lower in patients undergoing early versus late intubation (7338 deaths; 45.8% versus 53.5%; RR 0.92, 95% CI 0.87-0.97; p = 0.001). This was also the case in the sensitivity analysis of studies defining "early" as intubation within 24 h from admission in the intensive care unit (6279 deaths; 45.8% versus 53.6%; RR 0.93, 95% CI 0.89-0.98; p = 0.005).

CONCLUSION

Avoiding late intubation may be associated with lower mortality in critically ill patients without COVID-19.

Risk Factors for Post-operative Planned Reintubation in Patients After General Anesthesia: A Systematic Review and Meta-Analysis

Background

The occurrence of postoperative reintubation (POR) in patients after general anesthesia (GA) is often synonymous with a poor prognosis in patients. This is the first review analyzing scientific literature to identify risk factors of POR after general anesthesia. The purpose of this study was to collect currently published studies to determine the most common and consistent risk factors associated with POR after GA.

Methods

We have retrieved all relevant research published before April 2021 from PubMed, Embase, Web of Science, and the Cochrane Library electronic databases. These studies were selected according to the inclusion and exclusion criteria. The Z test determined the combined odds ratio (OR) of risk factors. We used OR and its corresponding 95% confidence interval (CI) to identify significant differences in risk factors. The quality of the study was evaluated with the NOS scale, and meta-analysis was carried out with Cochrane Collaboration's Revman 5.0 software.

Results

A total of 10 studies were included, with a total of 7,789 recipients of POR. We identified 7 risk factors related to POR after GA: ASA ≥ 3 (OR = 3.58), COPD (OR = 2.09), thoracic surgery (OR = 17.09), airway surgery (OR = 9.93), head-and-neck surgery (OR = 3.49), sepsis (OR = 3.50), DVT (OR = 4.94).

Conclusion

Our meta-analysis showed that ASA ≥ 3, COPD, thoracic surgery, airway surgery, head-and-neck surgery, sepsis and DVT were associated with POR after GA.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?, Identifier: CRD42021252466.

Effects of Timing of Invasive Mechanical Ventilation in Patients with Shock. An Analysis of the Multicenter Prospective Observational VOLUME–CHASERS Cohort

Objectives: Describe the variation in practice and identify predictors of invasive mechanical ventilation (IMV) use in shock. Explore the association between the timing of IMV initiation (“Early” vs. “Delayed”) on shock duration. Design: Multicenter, prospective, observational cohort study between September 2017 and February 2018 Setting: 34 hospitals in the United States and Jordan. Patients: Consecutive, adult, critically ill patients with shock, defined as a systolic blood pressure less than or equal to 90mm Hg, mean arterial pressure less than or equal to 65mm Hg, or need for a vasopressor medication. Interventions: None. Measurements and Main Results: “Early” IMV was defined as starting IMV 0–6 hours of shock onset and “Delayed” IMV was defined as starting IMV between 6 and 48 hours of shock onset. The primary outcome was shock–free days, defined as the number of days without shock after the first 48 hours of shock onset. Variation and predictors of IMV use were examined within the whole cohort as well as the subgroup of those intubated within 0–48 hours of shock onset. Mixed effects modeling with hospital site as a random effect showed that there was 7% variation by site in the use and timing of IMV in this shock cohort. In a propensity–matched model for the timing of IMV, “Early” IMV after shock onset was associated with more shock–free days when compared to “Delayed” IMV in those intubated within 0–48 hours of shock onset (Beta coefficient 0.65 days, 95% CI 0.14-1.16 days). Conclusions: Timing of IMV initiation for patients in shock has potentially important implications for patient outcomes and merits further study.

Timing to Intubation COVID-19 Patients: Can We Put It Off until Tomorrow?

Background: The decision to intubate COVID-19 patients receiving non-invasive respiratory support is challenging, requiring a fine balance between early intubation and risks of invasive mechanical ventilation versus the adverse effects of delaying intubation. This present study analyzes the association between intubation day and mortality in COVID-19 patients. Methods: We performed a unicentric retrospective cohort study considering all COVID-19 patients consecutively admitted between March 2020 and August 2020 requiring invasive mechanical ventilation. The primary outcome was all-cause mortality within 28 days after intubation, and a Cox model was used to evaluate the effect of time from onset of symptoms to intubation in mortality. Results: A total of 592 (20%) patients of 3020 admitted with COVID-19 were intubated during study period, and 310 patients who were intubated deceased 28 days after intubation. Each additional day between the onset of symptoms and intubation was significantly associated with higher in-hospital death (adjusted hazard ratio, 1.018; 95% CI, 1.005–1.03). Conclusion: Among patients infected with SARS-CoV-2 who were intubated and mechanically ventilated, delaying intubation in the course of symptoms may be associated with higher mortality. Trial registration: The study protocol was approved by the local Ethics Committee (opinion number 3.990.817; CAAE: 30417520.0.0000.0068).

Outcome after intubation for septic shock with respiratory distress and hemodynamic compromise: an observational study

BACKGROUND

Acute respiratory failure in septic patients contributes to higher in-hospital mortality. Intubation may improve outcome but there are no specific criteria for intubation. Intubation of septic patients with respiratory distress and hemodynamic compromise may result in clinical deterioration and precipitate cardiovascular failure. The decision to intubate is complex and multifactorial. The purpose of this study was to evaluate the impact of intubation in patients with respiratory distress and predominant hemodynamic instability within 24 h after ICU admission for septic shock.

METHODS

We conducted a retrospective analysis of a prospective registry of adult patients with septic shock admitted to the medical ICU at Mayo Clinic, between April 30, 2014 and December 31, 2017. Septic shock was defined by persistent lactate > 4 mmol/L, mean arterial pressure < 65 mmHg, or vasopressor use after 30 mL/kg fluid boluses and suspected or confirmed infection. Patients who remained hospitalized in the ICU at 24 h were separated into intubated while in the ICU and non-intubated groups. The primary outcome was hospital mortality. The first analysis used linear regression models and the second analysis used time-dependent propensity score matching to match intubated to non-intubated patients.

RESULTS

Overall, 358 (33%) ICU patients were eventually intubated after their ICU admission and 738 (67%) were not. Intubated patients were younger, transferred more often from an outside facility, more critically ill, had more lung infection, and achieved blood pressure goals more often, but lactate normalization within 6 h occurred less often. Among those who remained hospitalized in the ICU 24 h after sepsis diagnosis, the crude in-hospital mortality was higher in intubated than non-intubated patients, 89 (26%) vs. 82 (12%), p < 0.001, as was the ICU mortality and ICU and hospital length of stay. After adjustment, intubation showed no effect on hospital mortality but resulted in fewer hospital-free days through day 28. One-to-one propensity resulted in similar conclusion.

CONCLUSIONS

Intubation within 24 h of sepsis was not associated with hospital mortality but resulted in fewer 28-day hospital-free days. Although intubation remains a high-risk procedure, we did not identify an increased risk in mortality among septic shock patients with predominant hemodynamic compromise.

Use, timing and factors associated with tracheal intubation in septic shock: a prospective multicentric observational study

Background

No recommendation exists about the timing and setting for tracheal intubation and mechanical ventilation in septic shock.

Patients and methods

This prospective multicenter observational study was conducted in 30 ICUs in France and Spain. All consecutive patients presenting with septic shock were eligible. The use of tracheal intubation was described across the participating ICUs. A multivariate analysis was performed to identify parameters associated with early intubation (before H8 following vasopressor onset).

Results

Eight hundred and fifty-nine patients were enrolled. Two hundred and nine patients were intubated early (24%, range 4.5–47%), across the 18 centers with at least 20 patients included. The cumulative intubation rate during the ICU stay was 324/859 (38%, range 14–65%). In the multivariate analysis, seven parameters were significantly associated with early intubation and ranked as follows by decreasing weight: Glasgow score, center effect, use of accessory respiratory muscles, lactate level, vasopressor dose, pH and inability to clear tracheal secretions. Global R-square of the model was only 60% indicating that 40% of the variability of the intubation process was related to other parameters than those entered in this analysis.

Conclusion

Neurological, respiratory and hemodynamic parameters only partially explained the use of tracheal intubation in septic shock patients. Center effect was important. Finally, a vast part of the variability of intubation remained unexplained by patient characteristics.

Trial registration Clinical trials NCT02780466, registered on May 23, 2016. https://clinicaltrials.gov/ct2/show/NCT02780466?term=intubatic&draw=2&rank=1.

Noninvasive Ventilation for Critically Ill Subjects With Acute Respiratory Failure in the Emergency Department

BACKGROUND

We aimed to investigate the association between noninvasive ventilation (NIV) initiated in the emergency department and patient outcomes for those requiring invasive mechanical ventilation so that we could understand the effect of extended NIV use (ie, > 4 h) prior to invasive mechanical ventilation on patient outcomes.

METHODS

We conducted a retrospective single-center cohort study at an academic tertiary care hospital center. All emergency department patients with acute respiratory failure requiring invasive mechanical ventilation and admission to the ICU within 48 h of initial presentation over a 24-month period were included.

RESULTS

Subject characteristics, ventilator parameters, and clinical course were captured via electronic query, respiratory billing data, and standardized chart abstraction. A total of 431 subjects with acute respiratory failure requiring invasive mechanical ventilation within 48 h of arrival were identified, of whom 115 (26.7%) were exposed to NIV prior to invasive mechanical ventilation, with a median duration of 4 h (interquartile range 1.9-9.3). Based on a multivariable model controlling for covariates, any NIV exposure prior to invasive mechanical ventilation was not associated with an increased odds of persistent organ dysfunction or death. However, in the subset of subjects exposed to NIV, extended NIV use (ie, > 4 h) prior to invasive mechanical ventilation was associated with increased odds of persistent organ dysfunction or death (odds ratio 4.11, 95% CI 1.51-11.19). Extended NIV use was also associated with increased odds of in-hospital mortality (odds ratio 4.02, 95% CI 1.51-10.74).

CONCLUSIONS

Although any exposure to NIV prior to invasive mechanical ventilation did not appear to affect morbidity and mortality, extended NIV use prior to invasive mechanical ventilation was associated with worse patient outcomes, suggesting a need for additional study to better understand the ramifications of duration of NIV use prior to failure on outcomes. Given this early timeframe for intervention, future studies should be collaborations between the emergency department and ICU.

Center effect in intubation risk in critically ill immunocompromised patients with acute hypoxemic respiratory failure

BACKGROUND

Acute respiratory failure is the leading reason for intensive care unit (ICU) admission in immunocompromised patients, and the need for invasive mechanical ventilation has become a major clinical endpoint in randomized controlled trials (RCTs). However, data are lacking on whether intubation is an objective criteria that is used unbiasedly across centers. This study explores how this outcome varies across ICUs.

METHODS

Hierarchical models and permutation procedures for testing multiple random effects were applied on both data from an observational cohort (the TRIAL-OH study: 703 patients, 17 ICUs) and a randomized controlled trial (the HIGH trial: 776 patients, 31 ICUs) to characterize ICU variation in intubation risk across centers.

RESULTS

The crude intubation rate varied across ICUs from 29 to 80% in the observational cohort and from 0 to 86% in the RCT. This center effect on the mean ICU intubation rate was statistically significant, even after adjustment on individual patient characteristics (observational cohort: p value = 0.013, median OR 1.48 [1.30-1.72]; RCT: p value 0.004, median OR 1.51 [1.36-1.68]). Two ICU-level characteristics were associated with intubation risk (the annual rate of intubation procedure per center and the time from respiratory symptoms to ICU admission) and could partly explain this center effect. In the RCT that controlled for the use of high-flow oxygen therapy, we did not find significant variation in the effect of oxygenation strategy on intubation risk across centers, despite a significant variation in the need for invasive mechanical ventilation.

CONCLUSION

Intubation rates varied considerably among ICUs, even after adjustment on individual characteristics.