DISCUSSION
extubation failure, COPD, ARDS, PTS
COPD, ARDS
This is the first study that employed respiratory mechanics to compare different SBT modes and examine their underlying mechanism. Our findings revealed that pressure support with zero PEEP was more likely to induce a higher number of patient–ventilator asynchronies in difficult‐to‐wean patients.Subirà et alIn the SBT study by Esteban et alIn the present study, we found that patients showed longer inspiratory trigger delay and more abnormal triggers under the S1 mode (Figures After stratification based on the causes of mechanical ventilation, we found that under the S1 mode, COPD patients showed the longest inspiratory trigger delay, followed by ARDS patients and finally by PTS patients (Figure Despite enrolling DTW patients for this study, only a small number of cases exhibited extubation failure. Under the S1 mode, three patients with successful extubation could not tolerate the entire 30 min, whereas two patients with failed extubation could tolerate the entire S1 protocol, and one patient with failed extubation could not tolerate the entire S1 protocol. No significant differences were observed in the respiratory mechanics indices (e.g. Pes, Pga and Pdi) of these patients, thus suggesting that the S protocol, rather than the S1 protocol, could more accurately reflect the respiratory function of patients during SBTs.Although this study was a prospective crossover self‐controlled trial, it has the following limitations. First, it has a small sample size from a single centre, and a randomized controlled trial was not performed to compare the two protocols. Second, only a few causes of mechanical ventilation that were relatively uniform were included in this study. Third, only 30‐min trials were compared between the two protocols, and the respiratory mechanics indices for 2‐h trials were not observed. Fourth, extubation was actively followed by non‐invasive mechanical ventilation or high‐flow nasal cannula oxygen therapy. Thus, although none of the patients with successful SBT were reintubated, we cannot rule out the possibility that this was due to the absence of prolonged extubation. Finally, long‐term prognosis after weaning was not observed.