Assessment of Diaphragmatic Thickness Fraction (DTF) Along with Rapid Shallow Breathing Index (RSBI) as a Predictor of Successful Extubation in Mechanically Ventilated Patients: A Pilot Study in a Tertiary Care ICU

INTRODUCTION: Successful extubation is a critical milestone in the management of mechanically ventilated patients in the ICU. Early identification of candidates for successful extubation can reduce complications such as reintubation, prolonged ventilation, and ICU length of stay. Diaphragmatic Thickness Fraction (DTF), assessed through ultrasound, and Rapid Shallow Breathing Index (RSBI) have both shown potential as predictors of extubation success. However, their combined role has not been adequately explored. This pilot study aims to assess the utility of DTF in conjunction with RSBI as a predictor of successful extubation in mechanically ventilated ICU patients. OBJECTIVES: To assess changes in the variation of Diaphragmatic thickness from the time of intubation to extubation. To measure the accuracy of Diaphragmatic thickness fraction (DTF) along with Rapid Shallow Breathing Index (RSBI) as predictor of successful weaning and extubation. MATERIALS AND METHODS: This prospective pilot study was conducted in the ICU of kovai medical centre and hospital institute of health science and research (KMCH IHSR). Adult patients who were clinically stable and met the criteria for extubation were included. Pre-extubation assessments included the measurement of DTF using diaphragmatic ultrasound (inspiratory vs. expiratory diaphragm thickness) and calculation of RSBI (respiratory rate divided by tidal volume). The primary outcome was successful extubation within 48 hours, defined as no need for reintubation. Data were analyzed descriptively, and receiver operating characteristic (ROC) curves were used to assess the predictive ability of DTF, RSBI, and their combined use. RESULTS: A total of 35 eligible patients (mean age: 34.8 ± 11.2 years) were included in the study. During the weaning process, 3 patients failed to tolerate spontaneous breathing trials (SBT), and 4 were extubated without lung ultrasound (LUS) due to clinical urgency. Reintubation within 48 hours was required in 14% of patients. Those requiring reintubation (n=5) had significantly lower diaphragmatic thickening fraction (DTF%) values (41.2 ± 3.9) compared to patients who did not require reintubation (77.4 ± 16.8; p<0.0001). Analysis of DTF% identified a cutoff >45% as a strong predictor of successful extubation, with 93.7% sensitivity and 94.5% specificity (AUC=0.952, p<0.001). The mean diaphragmatic thickness during inspiration (DTi: 7.92 ± 2.12 mm) and expiration (DTe: 4.76 ± 1.22 mm) correlated significantly with extubation outcomes (p<0.001). Patients successfully extubated were transferred to the ward within 2-3 days, whereas those requiring reintubation or extended monitoring remained in the ICU for over four days. CONCLUSIONS: This pilot study suggests that both DTF and RSBI are promising markers for predicting successful extubation in mechanically ventilated ICU patients. The combination of these two measurements may offer enhanced predictive accuracy over individual parameters. Larger studies are needed to validate these findings and determine the clinical utility of the DTF-RSBI index as a tool for extubation decision-making in critically ill patients.