Hiroshi Kamijo, MD, PhD
Assistant Professor (Clinical Service)
Shinshu University School of Medicine
Matsumoto City, Japan
Disclosure information not submitted.
Itsuki Osawa, MD
Clinical Fellow
The University of Tokyo Hospital, Japan
Disclosure information not submitted.
Title: Predicting extubation failure using actual body weight-adjusted rapid shallow breathing index
Introduction: Extubation failure is associated with an increased risk of mortality and prolonged length of ICU stay. Rapid shallow breathing index (RSBI) is a well-known weaning index and one of the most studied predictors of extubation failure, but several studies have developed prediction models (e.g., logistic regression models) which may have better predictive ability than the conventional RSBI. Given that patients’ body weight has been shown to be an important predictor in these prediction models, it may be useful to adjust for body weight when using the RSBI to take advantage of RSBI’s ease of use at the bedside. In this study, we hypothesized that actual body weight (ABW)-adjusted RSBI or predicted body weight (PBW)-adjusted RSBI would predict extubation failure better than the conventional RSBI.
Methods: This is a retrospective cohort study using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. We included all adult patients (aged ≥18 years) in the database who were extubated for the first time after ICU admission, and excluded patients who were extubated for palliative care or died within 48 hours of extubation. Extubation failure was defined as reintubation within 48 hours after extubation. The RSBI was calculated with parameters recorded on the ventilator one hour after the start of the spontaneous breathing test (SBT) on the day of extubation. We compared the predictive performance of ABW-adjusted RSBI, PBW-adjusted RSBI, and conventional RSBI.
Results: A total of 3,470 eligible subjects were extracted from the MIMIC-IV. Among them, 350 cases experienced failed extubation. The area under the receiver operating characteristic curve (AUROC) of the conventional RSBI and ABW-adjusted RSBI for predicting extubation failure were 0.54 and 0.55, respectively (p-value < 0.05), and the AUROC of the conventional RSBI and PBW-adjusted RSBI were 0.52 and 0.52, respectively (p-value =0.93).
Conclusions: While the predictive ability was low for all models, ABW-adjusted RSBI predicted extubation failure better than the conventional RSBI.