Trials and Liberations: Spontaneous Breathing Trial Durations at an Academic Medical Center

Introduction: Prolonged intubation is a common issue encountered in intensive care units and one that leads poor overall outcomes. While it is well known that daily Spontaneous Breathing Trials (SBTs) reduces the duration of mechanical ventilation, there have been no studies evaluating the actual duration of SBTs in an academic ICU. Furthermore, there is no data to evaluate the reevaluation of patients after initiation of an SBT. The goal of our study is to retrospectively review SBT data at our own institution with plans to eventually initiate a timed intervention to reduce our duration of SBTs.


Methods: This study is a retrospective chart review of all mechanically ventilated patients admitted to the medical ICU at a tertiary academic medical center between January and June 2024. Patients intubated for less than 24 hours, terminally extubated, tracheostomy-dependent, or died while on mechanical ventilation were excluded. Duration of a patient’s first and second SBT, the outcome of their SBT’s, APACHE II score, and Charleston comorbidity scores were collected and compiled in REDCAP.


Results: We identified 261 records in our database. 131 patients were excluded from the study. 130 records were reviewed. Average age was 59 years. 76 (58%) were male and 54 (42%) were female. Average APACHE II score at time of intubation was 19. Average Charlson comorbidity index was 4. Average ventilator days prior to first SBT was 2 days. Average duration of first SBT was 894 minutes, with 50% of patients extubated after initial SBT. Average duration of second SBT was 806 minutes, with 59% extubated after. There were 20 patients who required greater than 2 SBTs.


Conclusions: This study demonstrates that in the Medical Intensive Care Unit at Hershey Medical Center, we found that patients who required mechanical ventilation had an initial SBT of 894 minutes. This is well above the recommended 30 -120 minute duration. There are limitations of our system as to knowing when a patient is placed on a true SBT or rather placed on pressure support/CPAP mode for patient comfort or ventilator dyssynchronies. It must be determined whether the slow weaning of patients on PS/CPAP modes contributes to prolonged mechanical ventilation. In the future, we plan to implement a timed intervention to hopefully reduce our duration of SBT by 75%.