Comparison of Methods for Spontaneous Breathing Trials

Abstract

Background: The rapid shallow breathing index (RSBI) is a measurement that may be used to predict successful extubation and liberation from mechanical ventilation. The original study used a T-piece during a spontaneous breathing trial (SBT) and showed an RSBI less than 105 to be the acceptable parameter for successful extubation. The current standard in most institutions is to perform SBT and measure an RSBI while using the ventilator, typically with Pressure Support (PS) of 5 cm H₂O and PEEP of 5 cm H₂O. We hypothesized that an SBT using PS of 0 cm H₂O, PEEP of 0 cm H₂O with automatic tube compensation (ATC) would create a significant difference in the accuracy of using RSBI as a predictor for successful extubation when compared to PS of 5 cm H₂O and PEEP of 5 cm H₂O. Methods: After IRB approval, we performed a retrospective chart review study of all patients admitted to R Adams Cowley Shock Trauma Center in the Multi-Trauma Critical Care (MTCC) during 2015 that had SBT performed with the two various SBT settings to determine the reintubation rate. Data were also collected on patients that required noninvasive ventilation (NIV) or high flow nasal cannula (HFNC) post-extubation. Results: There were 201 patients extubated that completed an SBT on PS of 5 cm H₂O PEEP of 5 cm H₂O and 12.56% required re-intubation which wasn’t significant but double the rate of 5.3% of 95 patients that were reintubated when using an SBT of on PS of 0 cm H₂O, PEEP of 0 cm H₂O, and ATC. Conclusions: The more ventilation support provided during an SBT, the less likely an RSBI < 105 is as accurate. There was no significant difference between the two methods of SBT, but the reintubation rate was greater when using higher settings.