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

October 1, 2025 Leave a comment

Study Reference

Burns KEA, Wong J, Rizvi L, et al. Frequency of screening and spontaneous breathing trial techniques: A randomized clinical trial. JAMA [Internet] 2024 [cited 2024 Oct 11]; Available from: https://jamanetwork.com/journals/jama/articlepdf/2824928/jama_burns_2024_oi_240116_1728315008.69577.pdf

Brief Summary for Clinicians

About The Study

This large multicenter randomized trial (N=797) conducted across 23 North American ICUs tested two key questions about ventilator liberation: How often should we screen patients for readiness to wean? (once daily vs. more frequently) and What technique should we use for spontaneous breathing trials? (pressure support with PEEP vs. T-piece).

Key Findings

Primary planned analysis (assuming no interaction):

  • Screening frequency: No significant difference in time to successful extubation between once-daily vs. more frequent screening (HR 0.88, 95% CI 0.76-1.03, p=0.12)
  • SBT technique: No significant difference between pressure support vs. T-piece (HR 1.06, 95% CI 0.91-1.23, p=0.45)

However, an unexpected significant interaction was found (p=0.009), requiring pairwise comparisons:

Time to successful extubation by group:

  • Once-daily + pressure support: 2.0 days (shortest)
  • Once-daily + T-piece: 3.1 days
  • More frequent + T-piece: 2.9 days
  • More frequent + pressure support: 3.9 days (longest)

Key pairwise findings:

  • When using pressure support SBTs, more frequent screening (vs. once-daily) increased time to successful extubation (HR 0.70, 95% CI 0.50-0.96, p=0.02)
  • When using once-daily screening, pressure support (vs. T-piece) did not significantly reduce time to successful extubation (HR 1.30, 95% CI 0.98-1.70, p=0.08)
  • Time to first successful SBT was shortest with once-daily screening + pressure support (median 0.8 days vs. 1.1 days for T-piece, HR 1.4, p=0.007)

Clinical Implications

  1. The combination matters: This study suggests that screening frequency and SBT technique may interact in ways that affect liberation timing
  2. Once-daily screening with pressure support SBTs appeared to result in the fastest time to successful extubation, potentially through:
    • Earlier identification of SBT readiness
    • Lower work of breathing with pressure support enabling earlier passage of SBTs
    • Possible clinician willingness to extubate after morning pressure support SBT success
  3. More frequent screening with pressure support unexpectedly increased time to extubation, possibly due to:
    • Clinician reluctance to extubate after afternoon SBT success (waiting for next day)
    • Unmeasured confounding factors
    • Workflow and cognitive bias issues
  4. Safety: Reintubation rates were similar across all groups (8-12%), suggesting these strategies did not compromise safety
  5. Protocol adherence was high (violations 4.6-10.2%), supporting feasibility of implementation

Important limitations:

  • This was an unblinded trial from North American centers only
  • The significant interaction was unexpected and reduces statistical power for secondary analyses
  • Patients with tracheostomy and those in neuro/neurosurgical ICUs were excluded
  • The interaction finding, while statistically significant (p=0.009), requires confirmation in future studies

Bottom line: While the main effects showed no differences, the unexpected interaction suggests that once-daily screening combined with pressure-supported SBTs may optimize time to extubation. However, the mechanisms underlying this interaction remain unclear and warrant further investigation before changing practice patterns. Clinicians should interpret these findings cautiously given the post-hoc nature of the interaction analysis.

Physiological Considerations for SBT Technique Selection

While this trial showed that once-daily screening with pressure-supported SBTs achieved the fastest time to extubation, there are important physiological reasons why clinicians may prefer T-piece or zero pressure support (PS 0/PEEP 0) SBTs for certain patients:

Pressure support reduces work of breathing substantially: Even modest pressure support (5-8 cm Hâ‚‚O) decreases inspiratory work by 30-60%, and PEEP of 5 cm Hâ‚‚O can reduce work by an additional 40%. This means pressure-supported SBTs may underestimate the respiratory load patients will face after extubation.

Post-extubation conditions differ from intubated conditions: After extubation, upper airway resistance increases due to laryngeal edema and inflammation from the endotracheal tube. This increased resistance often equals or exceeds the resistance of the endotracheal tube itself, effectively negating any benefit from tube removal. Additionally, the concept of “physiologic PEEP” from vocal cord closure is largely a myth—most patients’ end-expiratory lung volume approximates the relaxation volume of the respiratory system (where elastic recoil pressure is zero).

T-piece or zero support SBTs better replicate post-extubation physiology: For patients at high risk for extubation failure—particularly those with cardiac dysfunction, borderline respiratory reserve, or obesity—conducting a 30-60 minute trial without pressure support provides a more realistic and specific test of their ability to sustain spontaneous breathing after extubation. This approach may identify patients who pass pressure-supported SBTs but subsequently develop post-extubation respiratory or cardiac failure.

The choice between SBT techniques may need to be individualized: pressure-supported SBTs may expedite liberation in lower-risk patients, while T-piece or zero-support trials may provide an important safety margin for higher-risk patients, even if this results in a modest delay in extubation.

Reference

Burns KEA, Wong J, Rizvi L, et al. Frequency of screening and spontaneous breathing trial techniques: A randomized clinical trial. JAMA [Internet] 2024 [cited 2024 Oct 11];Available from: https://jamanetwork.com/journals/jama/articlepdf/2824928/jama_burns_2024_oi_240116_1728315008.69577.pdf

Sklar MC, Burns K, Rittayamai N, et al. Effort to breathe with various spontaneous breathing trial techniques: a physiologic meta-analysis. Am J Respir Crit Care Med. 2017;195(11):1477-1485. doi:10.1164/rccm.201607-1338OC

Straus C, Louis B, Isabey D, Lemaire F, Harf A, Brochard L. Contribution of the endotracheal tube and the upper airway to breathing workload. Am J Respir Crit Care Med. 1998;157(1):23-30. doi:10.1164/ajrccm.157.1.9707046

Sassoon CS, Light RW, Lodia R, Sieck GC, Mahutte CK. Pressure-time product during continuous positive airway pressure, pressure support ventilation, and T-piece during weaning from mechanical ventilation. Am Rev Respir Dis. 1991;143(3):469-475. doi:10.1164/ajrccm/143.3.469

Tobin MJ. Extubation and the myth of “minimal ventilator settings.” Am J Respir Crit Care Med. 2012;185(4):349-350. doi:10.1164/rccm.201201-0050ED

Goligher EC, Detsky ME, Sklar MC, et al. Rethinking inspiratory pressure augmentation in spontaneous breathing trials. Chest. 2017;151(6):1399-1400. doi:10.1016/j.chest.2017.02.033

Cabello B, Thille AW, Roche-Campo F, Brochard L, Gómez FJ, Mancebo J. Physiological comparison of three spontaneous breathing trials in difficult-to-wean patients. Intensive Care Med. 2010;36(7):1171-1179. doi:10.1007/s00134-010-1870-0

Leave a Reply