The effect of hypnotics on next day’s diurnal symptoms in hypercapnic patients receiving long-term nocturnal noninvasive ventilation

Background: Hypnotics are avoided for respiratory depression and risk of falling, in hypercapnic patients. About 30% of patients receiving long-term NIV take hypnotics for insomnia. It might be important to evaluate the effect of hypnotics on next day’s diurnal symptoms in such patients. Methods: 26 patients who received long-term NIV were studied prospectively. Patients received first polysomnography under NIV, taking whether zolpidem or placebo. After one week without hypnotics, they received second polysomnography taking an inverse medication. The effect of hypnotics on next day’s diurnal patients’ symptoms measured at VAS scale concerning sleepiness, floating, calm, comfort, dyspnea, and fatigue at 6:00, 9:00, 12:00, 15:00, and 18:00 was investigated. The correlations were also examined between symptoms and polysomnography deta (Apnea Hypopnea Index: AHI, Arousal Index: Ar, maximum PtcCO2, stage 3/4 sleep time: 3/4ST, total sleep time: TST). Results: 26 patients consist of 12 RTD, 6 COPD, 8 others. Their mean daytime PaCO2 was 55.1 mmHg. Next day’s diurnal symptoms tend to improve after sleeping on zolpidem. Significant improvement was observed; sleepiness at 18:00; floating at 15:00, calm at 6:00 and 9:00, comfort at 6:00, fatigue at 9:00 and 12:00, respectively. There were significant correlations between sleepiness and both TST and 3/4 ST, between floating and both TST and 3/4 ST, between calm and both AHI and Ar, and between comfort and both AHI and TST, respectively. Conclusion: Zolpidem may improve next day’s diurnal symptoms mainly due to increased TST in hypercapnic patients receiving long-term NIV.