Apnoeic and Hypopnoeic Load in Obstructive Sleep Apnoea: Correlation with Epworth Sleepiness Scale.

INTRODUCTION: Patients with obstructive sleep apnoea (OSA) often present with excessive daytime sleepiness (EDS) as measured by the Epworth Sleepiness Scale (ESS). However, the relationship between EDS and OSA severity as measured by the apnoea-hypopnoea index (AHI) remains inconsistent. We hypothesise that this may be due to the usage and equal weightage of apnoea and hypopnoea events used in determining AHI and that apnoea and hypopnoea load as measured by their total durations may be a better metric to use. We sought to investigate if apnoea or hypopnoea load can display better correlation with ESS. MATERIALS AND METHODS: Retrospective analysis of 821 patients with AHI ≥5, who underwent in-laboratory polysomnogram for suspected OSA from January 2015-December 2015, was performed. Objective factors on polysomnogram were correlated with ESS. RESULTS: ESS was correlated with age (r = -0.148, P <0.001), number of apnoeas (r = 0.096, P = 0.006), apnoea load (r = 0.102, P = 0.003), apnoea index (r = 0.075, P = 0.032), number of desaturations (r = 0.081, P = 0.020), minimum SpO2 (r = -0.071, P = 0.041), time SpO2 <85% (r = 0.075, P = 0.031) and REM sleep duration (r = 0.099, P = 0.004). Linear regression analysis found age (P <0.001), apnoea load (P = 0.005), REM (P = 0.021) and stage 1 sleep duration (P = 0.042) as independent factors correlated to ESS. The apnoea load calculated using duration in apnoea correlate with ESS in patients with severe OSA by AHI criteria compared to the mild category. CONCLUSION: AHI does not correlate with ESS. Younger age, longer apnoea, stage 1 and REM sleep were independently related to higher ESS though the correlations were weak. Apnoea load should be taken into account when determining OSA severity.

Hypnotic effect of jujubosides from Semen Ziziphi Spinosae.

ETHNOPHARMACOLOGICAL SIGNIFICANCE: Semen Ziziphi Spinosae, the seed of Ziziphus jujuba Mill. var. spinosa (bunge) Hu ex H.F. Chow has been widely used in treating insomnia and anxiety. AIM OF THE STUDY: In this study, we investigated the hypnotic effect of jujubosides, one of the major components (saponin) of Semen Ziziphi Spinosae, in both day and night period. MATERIALS AND METHODS: After the administration of jujubosides (9 mg/kg once per day for 3 days), sleep parameters were examined by EEG and EMG analysis in normal rats and the action of jujubosides on pentobarbital-induced sleep assessed by the loss-of righting reflex. RESULTS: During daytime (9:00-15:00), jujubosides significantly increased the total sleep and rapid eye movement (REM) sleep without significant influence on non-REM (NREM) sleep. During nighttime (21:00-3:00), jujubosides significantly increased the total sleep and NREM sleep especially the light sleep while showed no significant effect on REM sleep and slow wave sleep (SWS). In pentobarbital-treated mice, jujubosides significantly augmented the hypnotic effect of pentobarbital (45 mg/kg, i.p.), proved by increasing sleep time and this augmentative effect was potentiated by 5-hydroxytryptophan (2mg/kg, i.p.). Furthermore, jujubosides inhibited the para-chlorophenylalanine-induced suppression of pentobarbital-induced hypnosis. CONCLUSIONS: These results suggested that the hypnotic effect of jujubosides on normal rats may be influenced by circadian rhythm and the serotonergic system may involve in the hypnotic effect of jujubosides. Jujubosides may be good source of lead compounds for novel hypnotics.