Efficacy of auto-trilevel positive airway ventilation on patients with both obesity hypoventilation and moderate to severe obstructive sleep apnea syndromes

Abstract

Introduction To observe the efficacy of auto-trilevel positive airway pressure (Auto-trilevel PAP) ventilation on patients with both obesity hypoventilation syndrome (OHS) and moderate to severe obstructive sleep apnea syndromes (OSAS) by comparison of fixed bilevel positive airway pressure (BiPAP) ventilation. Materials and methods 17 patients with both OHS and moderate to severe OSAS were recruited. Three different positive airway pressure (PAP) modes issued by the ventilators (SOMNOvent auto-S, Weinmann Inc, Germany were used for 8h per night with each mode at each night and two nights' interval without any treatment among different modes. In mode one, the EPAP issued by BiPAP was titrated as the minimal positive pressure for disappearance of snoring. The same inspiratory positive airway pressure (IPAP) titrated by PaCO2 in mode 1 was used in modes 2 and 3 as well. However, the EPAP issued by BiPAP in mode 2 was 3cm H 2 O higher than that in mode 1. In mode 3 with autotrilevel PAP, the beginning of EPAP was set the same as that in mode 1 while the end of EPAP (EEPAP) was automatically adjusted to elevate based on upper airway patency condition. Comparisons were made for parameters before and after treatment as well as among different ventilation modes. The following parameters were compared such as nocturnal apnea hypopnea index (AHI), minimal SpO 2 (miniSpO 2 ), arousal index, sleep efficiency, morning PaCO 2 and daytime ESS. Results Compared with the parameters before ventilation therapies, there was a significant decrease in nocturnal AHI, arousal index, morning PaCO 2 and daytime ESS, but a significant increase in nocturnal miniSpO 2 and sleep efficiency caused by all three modes of ventilation (all P 2 and morning PaCO 2 in mode 2 (all P P 2 ( P 2 . Conclusion Auto-trilevel PAP ventilation is superior over fixed BiPAP ventilaiton for treatment of OHS with coexisting moderate to severe OSAS, since this novel PAP mode can achieve a higher efficacy in simultaneous removal of residual apnea hypopnea events and correction of hypercapnia as well as in achieving a higher sleep quality and lower daytime sleepiness. Acknowledgement Thanks to the Weinmann Inc, Germany which provided our research with Auto-trilevel PAP ventilators for clinical study.