Patient-Ventilator Asynchrony and Duration of Mechanical Ventilation: An Observational Study

Patient-ventilator asynchrony (PVA) is defined as a mismatch between the patient’s respiratory demand and the ventilatory support delivered during mechanical ventilation (MV). Although common, PVA is associated with adverse outcomes, including prolonged MV and increased morbidity. Methods: This cross-sectional observational study included adult ICU patients receiving invasive mechanical ventilation for more than 24 hours. PVA was assessed through visual analysis of pressure-time, flow-time, and volume-time waveforms recorded in two-minute videos. The asynchrony index (AI) was calculated and classified as <10% or ≥10%. Clinical and ventilatory variables were analyzed using nonparametric tests, logistic regression, and ROC curve analysis. Results: Eighty-three patients were included. PVA was identified in 21.7% of patients, with 14.5% presenting AI ≥ 10%. Patients with PVA had longer MV duration (18.5 vs. 8.0 days; p < 0.01). MV duration was associated with PVA (OR 1.29; 95% CI 1.15 - 1.46; p < 0.01). ROC analysis demonstrated high discriminatory capacity (AUC 0.91). However, this finding should be interpreted cautiously due to the bidirectional relationship between MV duration and PVA. Conclusion: PVA is frequent and associated with prolonged mechanical ventilation. These findings highlight the importance of systematic monitoring and optimization of ventilatory support.