Comparison Between Auto-trilevel And Bilevel Positive Airway Pressure Ventilation For Treatment Of Patients With Concurrent Obesity Hypoventilation Syndrome And Obstructive Sleep Apnea Hypopnea Syndrome

Purpose Our study aims to compare the difference in clinical efficacy between auto-trilevel positive airway pressure?auto-trilevel PAP?ventilator and conventional fixed bilevel positive airway pressure?BiPAP?ventilator for obesity hypoventilation syndrome?OHS?patients with coexisting moderate or severe obstructive sleep apnea hypopnea syndrome?OSAHS?.Methods Twenty-three OHS patients with moderate or severe OSAHS which were diagnosed enrolled between January 2015 and September 2017 underwent ventilation by three different modes of positive airway pressure?PAP?for 8h per night.All those patients were excluded because they could not tolerate the higher IPAP during sleep or felt discomforted with the nasal masks on their face during sleep.Our enrolled patients had an average body mass index?BMI?of?35.3±3.2?kg/m²,an average PaCO₂ levels of?57.3±4.8?mmHg during wakefulness before PAP treatment.The inspiratory positive airway pressure?IPAP?decided by PaCO₂ was consistently used for modes 1,2,and 3.In mode 1,the expiratory positive airway pressure?EPAP?issued by BiPAP was decided by the minimal PAP levels for cessation of snoring.However,in mode 2,the EPAP was fixed at 3 cmH₂O higher than this value.With the use of auto-trilevel PAP in mode 3,the EPAP was set to initially match that of mode 1 but the end of EPAP?EEPAP?was automatically regulated to be elevated according to upper airway patency condition.No positive airway pressure?PAP?therapy was carried out at two nights'interval as a washout period between each mode.We compared the following parameters including apnea hypopnea index?AHI?,minimalSpO₂?miniSpO₂?,arousal index?AI?,and sleep efficiency during sleep;PaCO₂ in the morning and Epworth sleepiness score?ESS?at daytime were measured prior to and during PAP treatment as well as between three selected PAP modes.Results Compared with the AHI?41.2±11.8?/h before ventilation therapies,AHI decreased significantly after treatment with each non-invasive ventilation?NIV?mode?all P<0.01?,Mode 1 was reduced to?6.1±1.4?/h,mode 2 to?2.7±1.2?/h and mode 3 to?3.2±0.8?/h.Comparison among three NIV modes revealed a significant difference in AHI from mode1 to mode 2 NIV treatment and from mode 1 to mode 3 NIV treatment?all P<0.05?.The miniSpO₂ level before NIV treatment was?69.3±9.2?%,the levels were all obviously elevated by each NIV treatment mode?all P<0.01?,mode1?85.7±4.4?%,mode2?91.2±3.5?%and mode3?91.2±3.5?%,respectively.The miniSpO₂ during mode 1 NIV treatment was remarkablely lower than that at mode 2 and mode 3 NIV treatment?P<0.01?,but no significant difference in minSpO₂ was detected between mode 2 and mode 3 NIV treatment?P>0.05??table 2?.The levels of PaCO₂ at 6:00 A.M.following nocturnal NIV therapy were invariably decreased in all three modes of NIV treatment than those?57.3±4.8?mmHg before NIV treatment,they are mode 1?41.8±3.4?mmHg,mode 2?48.9±3.2?mmHg and mode 3?42.3±2.9?mmHg,respectively.Comparison of post-NIV PaCO₂ levels found a significant difference not only between mode 1and mode 2 but also between mode 2 and mode 3 NIV treatment?all P<0.05?,even though no significant changes was found between mode 1 and mode 3 NIV treatment?P>0.05?.Sleep efficiency?total sleep time,TST/total recording time,TRT?%became remarkably higher at each mode of PAP treatment than that before NIV treatment?all P<0.01?,the sleep efficiency before NIV treatment was?65.3±9.1?%,those of the three PAP treatments were:mode 1?78.4±6.9?%,mode 2?81.4±8.6?%and mode 3?90.1±6.3?%,respectively,there was statistical significance?all P<0.01?.Comparing the sleep efficiency of different NIV treatment modes,it was found that the sleep efficiency of mode 3 was significantly higher than that of mode 1 and mode2?P<0.01?.Among the three variable modes,mode 3 resulted in the lowest arousal index and daytime ESS.Compared to mode 1,mode 2 demonstrated a significantly reduced AHI and an elevated miniSpO₂ and morning PaCO₂?all P<0.05?,while mode3 was associated with a decreased AHI,an increased miniSpO₂?all P<0.05?,and no statistical change of PaCO₂ following the end of PAP treatment?P>0.05?.Comparison between mode 2 and mode 3 revealed that mode 3 had a significantly lower PaCO₂?P<0.05?,but displayed no remarkable changes of AHI and miniSpO₂?all P>0.05?.Conclusion Compared to fixed BiPAP ventilation,auto-trilevel PAP ventilation could more effectively correct hypercapnia,achieve lower index of nocturnal apnea and hypopnea,more improved sleep quality,and lower daytime sleepiness score.Auto-trilevel PAP ventilation is therefore more efficacious than conventional BiPAP ventilation in non-invasive ventilation therapy for OHS patients with concurrent moderate or severe OSAHS.