An Integrative Index for Predicting Extubation Outcomes After Successful Completion of a Spontaneous Breathing Trial in an Adult Medical Intensive Care Unit

Abstract

Background: Among respiratory predictors, rapid shallow breathing index (RSBI) has been a commonly used respiratory parameter to predict extubation outcomes. However, the outcome of prediction remains inconsistent. Regarding nonrespiratory predictors, serum albumin, hemoglobin, bicarbonate, and patients' alertness have been reported to be associated with successful weaning or extubation. We aimed to develop an integrative index combining commonly used predictors in the adult medical intensive care units (MICUs) and to compare the predictability of the index with RSBI.

Methods: This prospective observational study with retrospective data collection of planned extubations was conducted in a 14-bed adult MICU. We enrolled patients who received mechanical ventilation via an endotracheal tube in the adult MICU for >24 hours and passed a 2-hour spontaneous breathing trial and underwent extubation. Extubation failure was defined as reinstitution of invasive mechanical ventilation within 48 hours of extubation. Respiratory parameters and Glasgow Coma Scale (GCS) scores of patients were recorded prospectively. Nonrespiratory parameters were recorded retrospectively. Logistic regression was used to determine significant predictors of extubation outcomes.

Results: Fifty-nine patients comprising 70 extubations were enrolled. Extubation failure was significantly and positively associated with lower serum albumin (albumin < 2.6 g/dL, odds ratio [OR] = 5.1; 95% confidence interval [CI], 1.04-24.66), lower hemoglobin (hemoglobin < 10.0 g/dL, OR = 10.8; 95% CI, 2.00-58.04), and lower GCS scores (GCS score ≤ 8, OR = 6.1; 95% CI = 1.15-32.34). By using an integrative index combining the 3 parameters together, the sensitivity and specificity to predict extubation outcomes were 78.6% and 75.9%, respectively. The area under the receiver operating characteristic curve of the index was significantly higher than RSBI (0.84 vs 0.61, P = .026).

Conclusion: The integrative index combining serum albumin, hemoglobin, and GCS scores could predict extubation outcomes better than RSBI in an adult MICU.

Keywords: endotracheal extubation; integrative index; intensive care unit; mechanical ventilation; rapid shallow breathing index; ventilator weaning.