ATRIAL-NATRIURETIC-PEPTIDE LEVELS IN THE SLEEP APNOEA HYPOPNOEA SYNDROME/

Background - Patients with the sleep apnoea/hypopnoea syndrome have in creased salt and water excretion at night which has been reported to b e associated with an increase in plasma levels of atrial natriuretic p eptide (ANP). A study was performed to determine whether any rise in p lasma ANP levels was related to nocturnal hypoxaemia. Methods - Nine p atients with sleep apnoea/hypopnoea syndrome were studied on two night s, one breathing air and the other 28% oxygen, the order being randomi sed. Venous levels of ANP, aldosterone, and renin activity were measur ed. Results - No decrease in plasma ANP levels on oxygen was seen, and , indeed, there was no evidence of an overnight increase in ANP levels . Conclusion - Oxygen therapy does not diminish nocturnal plasma ANP l evels in patients with sleep apnoea/hypopnoea syndrome.