Assessment of the Rapid Shallow Breathing Index, Integrative Weaning Index, and Dead Space to Tidal Volume Ratio by Respiratory Failure Type in Successfully Weaned Emergency Department Patients
Medicina (Lithuania), vol.61, no.8, 2025 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 61 Issue: 8
- Publication Date: 2025
- Doi Number: 10.3390/medicina61081438
- Journal Name: Medicina (Lithuania)
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Directory of Open Access Journals
- Keywords: mechanical ventilator, respiratory dead space, respiratory failure, tidal volume, weaning
- Kütahya Health Sciences University Affiliated: Yes
Abstract
Background/Objectives: Mechanical ventilation is essential in the management of acute respiratory failure (RF); however, prolonged use increases the risk of complications. Accurate predictors are therefore needed to guide timely weaning. The Rapid Shallow Breathing Index (RSBI), the dead space to tidal volume ratio (VD/VT), and the Integrative Weaning Index (IWI) are among the key indices used to assess weaning readiness. This study aimed to examine whether these indices differ between patients with Type 1 (hypoxemic) and Type 2 (hypercapnic) respiratory failure who were successfully extubated in the emergency department, in order to explore their physiologic variability across respiratory failure phenotypes. Methods: This cross-sectional study included 35 adult patients (23 with Type 1 RF, 12 with Type 2 RF) who were successfully weaned from mechanical ventilation in the Emergency Department of a tertiary care hospital between 2022 and 2024. RSBI, VD/VT, IWI, and arterial blood gas parameters were recorded. Descriptive and comparative statistical analyses were performed, with significance set at p < 0.05. Results: There were no significant differences in age, gender, or comorbidities between the groups. Type 2 RF patients had higher FiO2 requirements (37.5% vs. 30.0%; p = 0.03) and PaCO2 levels (49.1 ± 9.65 mmHg vs. 40.3 ± 4.49 mmHg; p < 0.001). The PaO2/FiO2 ratio was lower in the Type 2 group (169 ± 49.6) compared to the Type 1 group (244 ± 95.6; p = 0.017). VD/VT ratios were significantly higher in Type 2 RF patients (0.37 ± 0.04 vs. 0.29 ± 0.13; p = 0.046). RSBI values were identical between groups (40.0 in both; p = 1.00), and IWI values showed no significant difference (70.8 ± 30.7 vs. 79.3 ± 32.5; p = 0.45). Conclusions: Although RSBI and IWI values were similar across respiratory failure types, patients with Type 2 RF demonstrated higher VD/VT ratios and lower PaO2/FiO2, indicating reduced gas exchange and alveolar ventilation efficiency. These findings suggest that VD/VT may be a more useful parameter for assessing weaning readiness in hypercapnic patients.