INCREASED NOREPINEPHRINE VARIABILITY IN PATIENTS WITH SLEEP-APNEA SYNDROME

OBJECTIVE: TO assess the plasma arterial catecholamine response to nocturnal desaturation in a group of patients with a history suggestive of sleep apnea. PATIENTS AND METHODS: At a Veterans Affairs hospital, 10 patients who had a history consistent with sleep apnea syndrome were involved in the study. Arterial plasma catecholamines were measured at varying intervals during a 5 1/2-hour sleep study. Eighteen samples per patient were analyzed. RESULTS: AS the hemoglobin saturation decreased, the variability in plasma norepinephrine increased significantly (r = -.78, P = 0.004). As the hemoglobin saturation fell, there was a trend towards higher concentrations of plasma norepinephrine (r = -.53, P = 0.06). As the hemoglobin saturation decreased, the variability in plasma epinephrine concentration was not significant (r = .42). CONCLUSION: The association between the degree of desaturation and the variability in norepinephrine suggests that norepinephrine is released in response to nocturnal desaturation.