- •The ventilatory efficiency of ILD patients on mechanical ventilation was decreased compared to that of individuals with normal ventilating lungs.
- •Ventilatory ratio (VR) of non-survivors within 24 h of intubation was higher than that of survivors in ILD patients.
- •The high value of VR of intubated patients within 24 h of intubation was an independent risk factor for ICU mortality after adjusting for other factors.
- •VR could be used as a simple bedside index of impaired ventilation.
Ventilatory ratio (VR) is a simple bedside index of ventilatory efficiency. Interstitial lung disease (ILD) is a diverse group of diseases that causes fibrosis or inflammation of the pulmonary parenchyma, and the main clinical manifestation is hypoxemia. To date, no study has explored ventilation efficiency in patients with ILD.
This study aimed to explore the features of VR in mechanically ventilated patients with ILD and their relationship with intensive care unit (ICU) mortality.
In this retrospective analysis, we included mechanically ventilated patients with ILD in the ICU of West China Hospital, Sichuan University, from 2013 to 2021. Demographic data and mechanical ventilation (MV) parameters within 24 h of intubation were collected. The characteristics of VR and their relationships with ICU mortality were also analyzed.
224 patients were included in the final analysis. There were 146 males (53.9%), and the median age was 65 years (interquartile range [IQR]54∼74). The mean value of VR was 2.22, and VR was significantly higher in nonsurvivors than in survivors (1.79 vs 2.32, P < 0.001). A high VR value was an independent risk factor for ICU mortality (odds ratio=1.602, P = 0.038) after adjustment. A high value of VR was associated with a shorter survival time after admission to ICU (hazard ratio=1.485, P = 0.006)
VR in patients with ILD on MV was increased, and the VR of nonsurvivors within 24 h of intubation was higher than that of survivors. The high VR value within 24 h of intubation was an independent risk factor for ICU mortality after adjusting for other factors.
Abbreviations:VR (ventilatory ratio), ILD (interstitial lung disease), ICU (intensive care unit), MV (mechanical ventilation), VEmeasured (actual measured minute ventilation), PaCO2 (arterial carbon dioxide partial pressure), VEpredicted (predicted minute ventilation), PaCO2idea (ideal arterial carbon dioxide partial pressure), ARDS (acute respiratory distress syndrome), V/Q (ventilation-perfusion), IIP (idiopathic interstitial pneumonias), CTD-ILD (connective tissue disease-associated ILD), RR (respiratory rate), PaO2 (arterial oxygen partial pressure), FiO2 (fraction of inspired oxygen), PEEP (positive expiratory end pressure), SD (standard deviation), IQR (interquartile range), ROC (receiver operating characteristic), HR (hazard ratio)
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Published online: January 11, 2023
Accepted: January 3, 2023
Received in revised form: January 3, 2023
Received: July 20, 2022
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