Frequency of Screening and Spontaneous Breathing Trial Techniques: A Randomized Clinical Trial

Abstract

Importance: The optimal screening frequency and spontaneous breathing trial (SBT) technique to liberate adults from ventilators are unknown.

Objective: To compare the effects of screening frequency (once-daily screening vs more frequent screening) and SBT technique (pressure-supported SBT with a pressure support level that was >0-≤8 cm H2O and a positive end-expiratory pressure [PEEP] level that was >0-≤5 cm H2O vs T-piece SBT) on the time to successful extubation.

Design, setting, and participants: Randomized clinical trial with a 2 × 2 factorial design including critically ill adults who were receiving invasive mechanical ventilation for at least 24 hours, who were capable of initiating spontaneous breaths or triggering ventilators, and who were receiving a fractional concentration of inspired oxygen that was 70% or less and a PEEP level of 12 cm H2O or less. Recruitment was between January 2018 and February 2022 at 23 intensive care units in North America; last follow-up occurred October 18, 2022.

Interventions: Participants were enrolled early to enable protocolized screening (more frequent vs once daily) to identify the earliest that patients met criteria to undergo pressure-supported or T-piece SBT lasting 30 to 120 minutes.

Main outcome and measures: Time to successful extubation (time when unsupported, spontaneous breathing began and was sustained for ≥48 hours after extubation).

Results: Of 797 patients (198 in the once-daily screening and pressure-supported SBT group, 204 in once-daily screening and T-piece SBT, 195 in more frequent screening and pressure-supported SBT, and 200 in more frequent screening and T-piece SBT), the mean age was 62.4 (SD, 18.4) years and 472 (59.2%) were men. There were no statistically significant differences by screening frequency (hazard ratio [HR], 0.88 [95% CI, 0.76-1.03]; P = .12) or by SBT technique (HR, 1.06 [95% CI, 0.91-1.23]; P = .45). The median time to successful extubation was 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. An unexpected interaction between screening frequency and SBT technique required pairwise contrasts that revealed more frequent screening (vs once-daily screening) and pressure-supported SBT increased the time to successful extubation (HR, 0.70 [95% CI, 0.50-0.96]; P = .02). Once-daily screening and pressure-supported SBT (vs T-piece SBT) did not reduce the time to successful extubation (HR, 1.30 [95% CI, 0.98-1.70]; P = .08).

Conclusions and relevance: Among critically ill adults who received invasive mechanical ventilation for more than 24 hours, screening frequency (once-daily vs more frequent screening) and SBT technique (pressure-supported vs T-piece SBT) did not change the time to successful extubation. However, an unexpected and statistically significant interaction was identified; protocolized more frequent screening combined with pressure-supported SBTs increased the time to first successful extubation.

Trial registration: ClinicalTrials.gov Identifiers: NCT02399267 and NCT02969226.

Figure 1.. Patient Enrollment, Randomization, and Follow-Up

^aThe reasons included issues related to the consent process for 10 patients, imminent extubation for 6 patients, and no co-enrollment was permitted for 4 patients. In addition, the family or physician was not available (n = 1), the family was not approached (n = 1), there was no family consensus regarding participation (n = 1), and there was an ongoing judicial process (n = 1). ^bThe reasons included 3 patients who already underwent a spontaneous breathing trial, 1 patient who already underwent extubation during the index admission to the intensive care unit, and 1 patient who received invasive mechanical ventilation for longer than 2 weeks at the time of enrollment. ^cThe reasons included 2 patients who already underwent a spontaneous breathing trial, 2 patients who did not receive invasive mechanical ventilation for longer than 24 hours, 1 patient who had a positive end-expiratory pressure that was greater than 12 cm H₂O, and 1 patient who received invasive mechanical ventilation for longer than 2 weeks at the time of enrollment. ^dThe reasons included 6 patients who already underwent a spontaneous breathing trial, 1 patient who already underwent extubation during the index admission to the intensive care unit, and 1 patient with duplicate randomization. ^eThe reasons included 5 patients who already underwent a spontaneous breathing trial, 1 patient who did not receive invasive mechanical ventilation for longer than 24 hours, 1 patient who already underwent extubation during the index admission to the intensive care unit, and 2 patients with duplicate randomization.

Figure 2.. Cumulative Incidence Curves for the Probability of Time to Successful Extubation and Time to First Successful Spontaneous Breathing Trial (SBT)

The time to successful extubation was defined as the time from when unsupported, spontaneous breathing began and was sustained for at least 48 hours after extubation or disconnection for patients who had a tracheostomy after randomization. Patients were followed up until successful extubation, discharge from the intensive care unit, death, or 60 days after randomization (for patients dependent on ventilator support), whichever came first.