Increased nocturnal sodium excretion in obstructive sleep apnoea. Relation to nocturnal change in diastolic blood pressure.

OBJECTIVE: The mechanisms involved in the development and maintenance of hypertension in obstructive sleep apnoea (OSA) are not clear. We hypothesized that OSA patients have an abnormal renal handling of sodium and water during the night. MATERIAL AND METHODS: We studied 29 OSA patients and 19 healthy controls at night with serial determinations of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), arginine vasopressin (AVP), aldosterone (Aldo), fractional urinary excretion of sodium (FE(Na)), free water clearance (C(H2O)), urinary excretion of aquaporin 2 (u-AQP2), systolic blood pressure (SBP), diastolic blood pressure (DBP) and oxygen saturation. RESULTS: OSA patients had a higher FE(Na) (0.6 (0.4-1.0) versus 0.4 (0.3-0.6) %; p = 0.017), SBP (129 (114-145) versus 114 (106-122) mmHg; p = 0.001) and DBP (81 (72-87) versus 71 (65-74) mmHg; p<0.001) than healthy controls at night. In hypertensive OSA patients, the FE(Na) correlated significantly with the change in nocturnal DBP (r (2) = 0.411; p = 0.010). Mean level of AVP during the night was higher in OSA patients compared with healthy controls (1.1 (0.8-1.4) versus 0.8 (0.6-1.1) pmol/L; p = 0.033) and correlated with SBP. ANP, BNP, Aldo, C(H2O) and u-AQP2 were the same in OSA and controls. CONCLUSIONS: We conclude that the higher fractional excretion of sodium in OSA is most likely attributable to pressure natriuresis. The correlation between mean AVP and blood pressure suggests that AVP may be part of the pathogenetic mechanism underlying hypertension in these patients.

Abnormally increased endothelin-1 in plasma during the night in obstructive sleep apnea: relation to blood pressure and severity of disease.

BACKGROUND: The mechanisms involved in development and maintenance of hypertension in obstructive sleep apnea (OSA) are not clarified. We hypothesize that patients with OSA have an abnormal nocturnal level of some vasoactive hormones during the night. METHODS: We studied 32 patients with OSA and 19 healthy control subjects during The night-time with serial determinations of endothelin-1 (ENDO-1), angiotensin II (Ang II), renin (PRC), aldosterone (ALDO) in plasma, and blood pressure (BP), and oxygen saturation. RESULTS: Patients with OSA had a higher plasma level of ENDO than healthy controls and the mean nocturnal level of ENDO correlated significantly to the apnea-hypopnea index (AHI) as a measure of the severity of OSA. This correlation remained statistically significant after analysis in a general linear model with correction for confounders. Patients with OSA also had a significantly higher BP than healthy controls and the ambulatory BP correlated positively to the AHI in patients with OSA. No significant differences were measured in Ang II, PRC, and ALDO between the two groups. The correlation between AHI and ENDO supports OSA as a stimulus of endothelin release or increased endothelin levels contributing to the severity of OSA. CONCLUSIONS: Endothelin seems to be a pathogenic factor in generating hypertension in OSA.

Primary lung cancer in a chest clinic: diagnosis and prognosis.

This reports a retrospective study of primary cancer of the lung diagnosed in the chest clinics of the Odense and Assens counties in Denmark during the period 1960 to 1966. There were 212 patients, 171 of whom had been referred because of symptoms, and 41 who were found in group screening. Of the latter, 13 had no symptoms. The histologic diagnosis, the diagnostic procedures on which the diagnosis was based, and the treatment are reported. Twenty percent of the patients were alive after five years, as compared with the calculated 13.5 percent for all cancers of the lung in the two counties. A close collaboration between general practitioners, chest clinics, and departments of thoracic surgery is stressed as a means of further improving the prognosis.