Liberation from Mechanical Ventilation (MV) (1-3) represents an important challenge for physicians in Intensive Care Unit (ICU) because extubation failure, requiring re-intubation, increases several adverse outcomes and mortality (4).
The recent trial conducted by Subirà et al. examined the best strategy to conduct a Spontaneous Breathing Trial (SBT) to achieve successful extubation. In this randomized controlled trial, 1,153 adult patients, intubated and mechanically ventilated for at least 24h in 18 Spanish ICUs, were screened for SBT eligibility. 578 patients were randomized to a 2h T-piece-SBT and 575 to a 30 minutes SBT with 8 cmH₂O of Pressure Support Ventilation (PSV); 1,018 patients (88.3%) completed the trial.
The primary outcome was successful extubation with no re-intubation within 72h; secondary outcomes were re-intubation rate among SBT extubated patients, Length Of Stay (LOS) in hospital and ICU, 90-days and hospital mortality.
Research findings showed:

• a higher percentage of patients tolerated PSV-SBT vs T-piece- SBT and were extubated (92.5 vs 84.1%, p < 0.001);
• successful extubation without re-intubation within 72h, occurred more frequently in the PSV-SBT group vs T-piece-SBT (82.3% vs 74.0%, p < 0.001);
• re-intubation rate within 72h after SBT did not differ significantly between groups (11.1 in PSV-SBT vs 11.9% in T-piece-SBT), nor did the median hospital LOS (24 days vs 24 days) or ICU LOS (9 days in PSV-SBT vs 10 days in T-piece-SBT);
• PSV-SBT had significantly lower hospital and 90-days mortality (10.4 vs 14.9%, p = 0.02 and 13.2 vs 17.3%, p = 0.04, respectively).

Key points

• Patients receiving MV were more likely to tolerate a shorter and less demanding 30 minutes-PSV-SBT compared to a 2h-T-piece-SBT, achieving a higher successful extubation rate. This is probably due to the considerable waste of energy needed to breathe spontaneously through a small endotracheal tube that may lead to SBT intolerance.
• A high percentage of participants had a successful initial SBT suggesting that early recognition of extubation readiness is crucial.
• The lower 90 days and hospital mortality rates using a 30-minute PSV-SBT must be interpreted with caution, given that the study was not blinded and due to the absence of a standardized protocol on the use of Non-Invasive Ventilation (NIV) and high-flow oxygen therapy with nasal cannula (HFNT) to prevent extubation failure; in particular the use of NIV (8.9% vs 5.9%) and HFNT (15.8% vs 12.8%) was slightly more common in the PSV-SBT compare to T-piece-SBT group, although the difference did not reach statistical significance.
• Long-term outcomes, such as long-term survival and functional status in relation to the type of SBT, were not assessed.
  
  

References

1. Esteban A, Frutos F, Tobin MJ, et al; Spanish Lung Failure Collaborative Group. A comparison of four methods of weaning patients from mechanical ventilation. N Engl J Med 1995;332:345-50.
2. Brochard L, Rauss A, Benito S, et al. Comparison of three methods of gradual withdrawal from ventilatory support during weaning fron mechanical ventilation. Am J Respir Crit Care Med 1994;150:896.
3. Schmidt GA, Girard TD, Kress JP, et al; ATS/CHEST Ad Hoc Committee on Liberation From Mechanical Ventilation in Adults. Official executive summary of an American Thoracic Society/American College of Chest Physicians clinical practice guideline: liberation from mechanical ventilation in critically ill adults. Am J Respir Crit Care Med 2017;195:115-9.
4. Thille AW, Harrois A, Schortgen F, et al. Outcomes of extubation failure in medical intensive care unit patients. Crit Care Med 2011;39:2612-8.