Effect of Using the Rapid Shallow Breathing Index as Readiness Criterion for Spontaneous Breathing Trials in a Weaning Protocol

This study aimed to compare the effect of using versus not using the Rapid-Shallow Breathing Index (RSBI) as a readiness criterion for Spontaneous Breathing Trials (SBT) on SBT success. Daily readiness screens were performed within a respiratory therapist-driven weaning protocol. Patients who passed these screens underwent a one-time measurement of the RSBI and then a SBT regardless of RSBI result. The proportion of passed readiness screens reaching SBT success was compared to the proportion that would have been obtained if RSBI ≤ 105 br/min/L had been used as an additional screen criterion. Two hundred and fifty SBTs performed on 157 patients were analyzed. The sensitivity of RSBI ≤ 105 br/min/L to predict SBT success was 94.8% (95% CI 90.6-97.5). Relative to potentially using RSBI, 14.4% additional SBTs were performed. A third of these were successful, and no complications were detected in the rest that failed. The proportion of passed readiness screens reaching SBT success would have been 4% (95% CI 1.2-6.8) (P = 0.002) lower if RSBI had been used. The inclusion of the RSBI in a readiness screen may not be useful in a weaning protocol.