Effective non-invasive ventilation (NIV) therapy is dependent on optimal ventilator settings to maximize clinical benefit and patient tolerance. Intelligent volume-assured pressure support (iVAPS) is a hybrid mode of servoventilation, providing constant automatic adjustment of pressure support (PS) to achieve a target ventilation determined by the patient's requirements. In a randomized crossover trial, we tested the hypothesis that iVAPS, with automated selection of ventilator settings, was non-inferior to standard PS ventilation, with settings determined by an experienced health-care professional, for controlling nocturnal hypoventilation in patients naive to NIV.

Methods : Eighteen patients referred to a ventilator clinic with chronic obstructive or restrictive lung disease and newly diagnosed nocturnal hypoventilation (10 male, median (interquartile range): age 54(41–61) years, mean daytime PaO2 9.25(8.59–10.31) kPa, -PaCO2 6.38(5.93–6.65) kPa were randomized to iVAPS and standard PS. Polysomnography with transcutaneous CO2 monitoring was performed at baseline and 1 month after each treatment period. Nightly hours of therapy were recorded by the ventilator.

Results : iVAPS delivered a lower median PS compared with standard PS (8.3(5.6–10.4) vs 10.0(9.0–11.4) cmH2O; P = 0.001) for the same ventilatory outcome (mean overnight: SpO2 96(95–98) vs 96(93–97)%; P = 0.13 and PtcCO2 6.5(5.8–6.8) vs 6.2(5.8–6.9); P = 0.54). There was no difference in outcome between ventilator modes for spirometry, respiratory muscle strength, sleep quality, arousals or O2 desaturation index. Adherence was greater with iVAPS (5:40(4:42–6:49) vs 4:20(2:27–6:17) hh:mm/night; P = 0.004).

Conclusions : iVAPS servoventilation with automation of ventilation settings is as effective as PS ventilation initiated by a skilled health-care professional in controlling nocturnal hypoventilation and produced better overnight adherence in patients naive to NIV.