A large randomized clinical trial examining ventilator weaning strategies for critically ill adults revealed an unexpected interaction between screening frequency and spontaneous breathing trial techniques.
In the study, published in JAMA, investigators found that more frequent screening paired with pressure-supported spontaneous breathing trials (SBTs) significantly prolonged the time to successful extubation compared with once-daily screening.
The multicenter trial included 797 critically ill adult patients receiving invasive mechanical ventilation for more than 24 hours across 23 North American intensive care units. The patients were randomly assigned to receive either once-daily or more frequent screening to assess readiness for an SBT as well as either pressure-supported or T-piece SBTs.
The study population had a mean age of 62.4 years (standard deviation = 18.4 years), and 59.2% were men. The majority of the patients (58.1%) had acute respiratory failure as the primary diagnosis leading to mechanical ventilation.
Among the key findings were:
- A significant interaction was identified between screening frequency and SBT technique (P = .009 for interaction).
- More frequent screening with pressure-supported SBTs prolonged the time to successful extubation (hazard ratio [HR] = 0.70, 95% confidence interval [CI] = 0.50–0.96, P = .02) compared with once-daily screening.
- When T-piece SBTs were used, screening frequency did not significantly affect time to successful extubation (HR = 1.30, 95% CI = 0.98–1.70, P = .08).
- Median time to successful extubation varied: 2.0 days (95% CI = 1.7–2.7) for once-daily screening and pressure-supported SBT, 3.1 days (95% CI = 2.7–4.8) for once-daily screening and T-piece SBT, 3.9 days (95% CI = 2.9–4.7) for more frequent screening and pressure-supported SBT, and 2.9 days (95% CI = 2.0–3.1) for more frequent screening and T-piece SBT (P = .02 for difference among groups).
Secondary outcomes included:
- Time to first successful SBT was shortest in the once-daily screening and pressure-supported SBT group (median = 0.8 days, 95% CI = 0.7–1.0).
- The once-daily screening and pressure-supported SBT strategy was associated with a shorter median duration of ventilator support (46.7 hours, interquartile range [IQR] = 18.7–95.7), shorter ICU stay (5.0 days, IQR = 2.7–8.2), and shorter hospital stay (14.1 days, IQR = 7.5–29.7).
- Reintubation rates were similar across all groups, ranging from 8.1% to 11.8%.
Protocol adherence was high, with violations for screening frequency and SBT technique ranging from 4.6% to 10.2% of the participants. Adverse events were infrequent across all study groups, enhancing the reliability of the findings.
The investigators noted limitations, including the inability to blind clinicians to the interventions, the exclusion of patients with tracheostomies and those in neurological ICUs, and the trial's confinement to North American centers, which may affect generalizability.
The findings suggested the need for further research to confirm the interaction between screening frequency and SBT technique and to explore the underlying mechanisms.
Conflict of interest disclosures can be found in the study.