Gastric motility and autonomic activity during obstructive sleep apnea

Summary

Background

Patients with Obstructive Sleep Apnea Syndrome (OSAS) often experience gastroesophageal reflux disease (GERD).

Aim

To investigate gastric motility and autonomic nervous activity during sleep apnea.

Methods

The subjects of this study were 20 individuals with OSAS who experienced 10 or more sleep apnoea events per hour, as measured with a portable sleep polygraph. A percutaneous electrogastrography (EGG) and fast Fourier transformation analysis was carried out on the results. The mean amplitude was compared for bradygastria, normogastria and tachygastria. Spectral analysis of heart rate variability was performed, and low-frequency (LF) power, high-frequency (HF) power and the LF/HF ratio were measured. Oesophagogastroduodenal endoscopy was performed on each subject, and the presence of reflux oesophagitis (RE) was diagnosed according to the Los Angeles (LA) grade classification. Moreover, questionnaire for the diagnosis of reflux disease (QUEST) was carried out.

Results

Normogastria was significantly decreased, and brady-, tachygastria, or both were increased during sleep apnea (P < 0.01). There was no significant relation between LA grade classification of RE and severity of OSAS. The LF/HF ratio was significantly higher during sleep apnea for patients with RE and OSAS, but the opposite for those with RE without OSAS. Decreased percutaneous arterial oxygen saturation and normogastria were independent risk factors for the severity of RE.

Conclusions

The present study suggested that, in addition to decreased pressure on the pleural cavity, factors affecting the development of RE might include abnormal gastric motility, low oxygen, and increased sympathetic nervous activity during sleep apnea.