Abstract
Introduction: Patient-ventilator asynchrony (PVA) is frequent in COPD patients considered yet effectively treated by NIV.
Objective: To assess whether adjusting ventilator settings during polysomnography (PSG) might improve patient-ventilator synchronization, sleep quality and morning dyspnea (“deventilation dyspnea”).
Methods: 8 consecutive severe COPD patients (61±8 yrs, FEV1 30.4±8.7% of predicted values) treated by home NIV underwent two consecutive sleep studies. Patient's usual ventilator settings were applied during the first night. During the second titration night ventilator settings were adjusted in order to reduce PVA by using on-line PSG including TcPCO2/SaO2 monitoring.
Results: During titration, pressure support was reduced in all cases from 13.6±1.8 to 10.3±1.7cmH2O, p=.0005. This resulted in reduction of PVA index from 40.5%±31.0 to 6.7%±7.3 of time of recording, p=.009. Total sleep time, microarousal index and sleep efficiency were not significantly improved. NIV adjustments led to a marked decrease in morning “deventilation dyspnea” measured by a modified Borg scale (baseline 5.8±2.5; adjusted 2.3±1.6, p=.0059). Comfort of ventilation assessment using visual analog scales showed significant improvements in perceived PVA (p=.04), perception of leaks (p=.04) and overall quality of sleep (p=.01). Pressure support reduction had no effect on nocturnal TcPO2.
Conclusion: This study confirms a high 40% rate of PVA in severe COPD under home ventilation usually undetected without PSG. Adjusting ventilator settings using online PSG resulted in: improvements in patient ventilator synchronization, patient comfort and decreased “deventilation dyspnea” without negative impact on nocturnal TcPO2.
- © 2011 ERS