급성호흡곤란증후군에서 일회호흡량 변동성이 치료 결과에 미치는 영향

Abstract

Background: Excessive spontaneous breathing during mechanical ventilation can lead to patient self-inflicted lung injury. However, clinical data linking spontaneous breathing to treatment outcomes is insufficient. We aimed to evaluate the effect of tidal volume variability on ventilator-free days in mechanically ventilated patients with acute respiratory distress syndrome (ARDS) using high-resolution tidal volume data stored through the patient monitor. Methods: In this single-center, retrospective cohort study, adult ARDS patients who received mechanical ventilation in our medical intensive care unit between April 2018 and July 2019 were included. Study patients’ expiratory tidal volume data during the first 7 days of mechanical ventilation was collected every 2 seconds by the patient monitors. The included patients were dichotomized within each tidal volume stratum into high and low tidal volume variability groups based on the standard deviation of tidal volume values normalized by predicted body weight. The primary outcome was ventilator-free days. Results: A total of 108 ARDS patients were categorized into the high and low tidal volume variability groups (each 54 patients). The baseline characteristics of the two groups were comparable except for the height (165 ± 8 cm vs 162 ± 7 cm; P = 0.02). The ventilator-free days were significantly fewer in the high tidal volume variability group (0 [IQR, 0–16] days vs. 10 [IQR, 0–21] days; mean difference, -4.5 [95% CI, -8.3–-0.7] days; P = 0.01). After adjusting for age, sex, body mass index, APACHE II score, and baseline PaO2/FiO2 ratio, high tidal volume variability was significantly associated with zero ventilator-free days (odds ratio, 3.74; 95% CI, [1.55–9.06]; P = 0.003). Conclusion: Based on the high-resolution tidal volume data acquired from the patient monitor, high tidal volume variability during the first 7 days of mechanical ventilation in ARDS patients was associated with fewer ventilator-free days. Keywords: tidal volume variability; spontaneous breathing; patient self-inflicted lung injury; mechanical ventilation; ARDS