The rapid shallow breathing index (RSBI) as a predictor for extubation success in medical and surgical ICU patients: A retrospective cohort study

Abstract

Background: Endotracheal intubation and mechanical ventilation comprise common life support interventions for patients in intensive care units (ICUs). Premature or delayed extubation increases the risk of morbidity and mortality. Despite following weaning protocols, 10-20 % of patients fail extubation within 48 h. To improve extubation success, predictors such as the rapid shallow breathing index (RSBI-the ratio of respiratory rate to tidal volume) are needed. The current RSBI value (<105 breaths/min/L) comes from clinically outdated methods and small samples.

Objective: To identify the highest-performing RSBI threshold value associated with extubation success using current weaning protocols in a large sample of medical and surgical ICU patients.

Methods: Using secondary data from hospital records, receiver operating characteristic (ROC) analysis of the RSBI, measured immediately after a spontaneous breathing trial, was conducted for 1313 mechanically ventilated (≥ 48 h and ≤ 21 days) patients at one hospital in Saudi Arabia.

Results: The sample of 61.5 % medical and 38.5 % surgical patients included 65 % males with a mean age of 53 years and an extubation failure rate of 12 %. Ideal RSBI threshold values differed by medical and surgical samples. For each sample, the area under the ROC curve approximated 0.5 for the RSBI, and multivariable logistic regression identified a unique set of physiologic parameters to predict successful extubation.

Conclusion: The RSBI alone demonstrated low diagnostic performance for predicting successful extubation using current weaning protocols. However, results suggest needed updates for RSBI threshold values in current weaning protocols to optimize RSBI use with other predictors for extubation success.

Keywords: Eapid shallow breathing index (RSBI); Extubation outcome; Physiological predictors; Spontaneous breathing trial (SBT); Successful extubation; Weaning protocols; intensive care units (ICUs); pressure support (PS).