Prolonged weaning linked to worse outcomes in mechanically ventilated ICU patients

Patients on mechanical ventilation with delayed weaning attempts after meeting eligibility criteria had a higher risk for failure, according to study results presented at Society of Critical Care Medicine’s Critical Care Congress.

These results, which were simultaneously published in The Lancet Respiratory Medicine, also showed that only 65% of patients studied weaned successfully overall.

“Where the process of weaning becomes prolonged, the risk of dying and of increased length of stay in intensive care and hospital increases substantially,” John Laffey, MD, DSc, professor of anesthesia and intensive care medicine at University of Galway’s College of Medicine, Nursing and Health Sciences, said in a press release. “In terms of longer-term outcomes, older age and the duration of ventilation are the strongest predictors of survival and quality of life at 1 year following critical illness.”

In WEAN SAFE, an international, multicenter, prospective, observational cohort study, Laffey and colleagues analyzed 5,869 ICU patients (median age, 64 years; interquartile range [IQR], 51-74; 61.8% male) aged older than 16 years who received invasive mechanical ventilation for at least 2 days in 481 ICUs between Oct. 4, 2017, and June 25, 2018, to understand characteristics of the weaning process in this population.

The number of patients who successfully weaned off of ventilation — defined as no reintubation or death within 7 days of extubation — by day 90 served as the study’s primary outcome. Researchers also assessed weaning duration, hospital outcomes, timing of weaning events and factors related to weaning delay and failure to gain insight and improve the rate of successful weaning.

Of the total cohort, 3,817 (65%) patients experienced successful weaning by 90 days, indicating that the rest of the cohort could not be weaned off of mechanical ventilation, or died while still receiving mechanical ventilation.

Death occurred among 1,742 (31.8%) patients in the ICU — 63.7% of whom died before a separation attempt, 31.7% of whom died after a failed separation attempt, and 4.6% of whom died after weaning from ventilation — and 2,095 (38.3%) in the hospital, 16.8% of whom died after being discharged from the ICU.

Median time to weaning from the first separation attempt among the 4,523 (77.1%) patients who had at least one such attempt was 1 day (IQR, 0-4), with 22.4% having a delay of 5 or more days from weaning eligibility.

Of these patients, 64.7% had a short weaning process ( 1 day), 10.1% had an intermediate weaning process (2 to 6 days), 9.6% needing prolonged weaning ( 7 days) and 15.6% experiencing weaning failure (death, transfer or continued ventilation by 90 days).

Demographic factors linked to a higher risk for a delayed initiation of the first separation attempt included frailty, trauma admission and nontrauma neurological events admission, whereas cardiac arrest showed a lower risk.

Further, researchers observed an independent relationship between increased sedation scores and delayed initiation of weaning and, in turn, both of these factors had an independent association with weaning failure.

Older age, frailty and immunocompromised status were also related to weaning failure in those with at least one separation attempt, according to researchers.

“Despite the importance of the weaning process, this area is not well studied,” Laffey said in the release. “Our research on this clinical practice is the largest study to date to offer data relating weaning practices to outcomes from invasive mechanical ventilation in a global cohort of patients at risk for prolonged weaning and/or weaning failure.”

This study by the WEAN SAFE investigators presents important characteristics related to weaning from mechanical ventilation, according to an accompanying editorial by Samir Jaber, MD, PhD, head of the anesthesia and critical care department at Centre Hospitalier Universitaire Montpellier in France, and Audrey De Jong, MD, PhD, doctor at Centre Hospitalier Universitaire Montpellier.

“The WEAN SAFE study confirms the results of previous studies showing great heterogeneity in the clinical practices of weaning mechanical ventilation in intensive care units and their respective effects on the outcome,” Jaber and De Jong wrote. “This is a call for the realization of new international consensus guidelines for weaning from mechanical ventilation after the SARS-CoV-2 pandemic and taking into account personalized medicine (ie, phenotypes of the patients in intensive care units).”

References:

• Jaber S, et al. Lancet Respir Med. 2023;doi:10.1016/S2213-2600(22)00502-1.
• Pham T, et al. Weaning from mechanical ventilation in intensive care units across 50 countries: The WEAN SAFE prospective observational study. Presented at: Society of Critical Care Medicine’s Critical Care Congress; Jan. 21-24, 2023; San Francisco.
• University of Galway research on ‘weaning’ patients from ventilation aims to improve outcomes. https://www.universityofgalway.ie/about-us/news-and-events/news-archive/2023/january/university-of-galway-research-on-weaning-patients-from-ventilation-aims-to-improve-outcomes.html. Published Jan. 23, 2023. Accessed Jan. 24, 2023.