In intensive care units (ICUs), the decision to extubate patients is critical. Approximately 15% of patients require reintubation after planned extubation, with rates exceeding 20% in high-risk patients. A spontaneous breathing trial (SBT) is recommended before extubation to evaluate readiness by simulating post-extubation conditions.
Choosing the appropriate SBT is crucial. An overly challenging trial can delay extubation and prolong mechanical ventilation, while an overly easy trial may miss those likely to fail, leading to reintubation and increased mortality. In North America, the common method is pressure-support ventilation (PSV) with PEEP, while Europe typically uses either a T-piece or PSV without PEEP. Studies suggest that PSV is easier to pass and hastens extubation without increasing reintubation risk. However, the benefits of reconnecting to the ventilator after a successful SBT remain debated.
Do you think reconnection to the ventilator for 1 hour following a successful SBT can decrease the rate of reintubation?
Yes
No
Not sure!
The Trial!
A new trial was published in Chest and explored the physiologic effect of reconnection to the ventilator for 1 hour following a successful SBT. The study, part of the TIP-EX trial, compared SBTs using a T-piece versus PSV in high-risk patients. Conducted at the University Hospital of Poitiers, the study focused on physiological aspects. Patients were intubated for at least 24 hours, aged >65 years, or had chronic cardiac or respiratory conditions. They underwent SBTs with either a T-piece or PSV. Successful trials were followed by one hour of reconnection to the ventilator before extubation.
End-expiratory lung volume (EELV) and regional lung changes were measured using nitrogen washin-washout and electrical impedance tomography (EIT). Measurements were taken before, during, and after the SBT, focusing on recovery of EELV and lung impedance following reconnection.
From September 2020 to April 2021, 34 patients were randomized, with 26 included in the ancillary study. The study found that SBTs, particularly with a T-piece, significantly decreased end-expiratory lung volume (EELV). Reconnection to the ventilator for one hour after SBTs fully recovered EELV regardless of the SBT type. Reconnecting for ten minutes was sufficient to recover EELV after PSV but not after T-piece SBTs. The higher initial failure rate with T-piece SBTs aligned with previous findings, likely due to increased inspiratory effort without pressure support. The study also suggested that the observed clinical benefits of reconnection might be due to recovery from alveolar derecruitment rather than diaphragm fatigue.
Conclusion
These findings highlight the importance of post-SBT reconnection in recovering alveolar derecruitment after SBT, particularly in high-risk patients. However, this study only assesses the functional effects of the procedure and shows the improvement in the EELV during the procedure. More data is needed to determine whether these physiological benefits last longer and translate into a decreased reintubation rate. Future studies should explore the extent of alveolar derecruitment during SBTs and test interventions during the weaning process to optimize extubation outcomes.