Nocturnal polyuria with repeated micturitions during the night is a clinically evident feature of obstructive sleep apnea syndrome (OSAS). These effects are reversed by continuous positive airway pressure (CPAP). There is some evidence that atrial natriuretic peptide (ANP) and catecholaminergic activity may be implicated in the pathogenesis of these symptoms. We studied these biochemical parameters in six patients with severe OSAS during two nights: the first (basal) in their normal conditions and the second during CPAP treatment. CPAP treatment reversed apnea episodes in all our patients. A significant (p less than 0.035) reduction of nocturnal urine volume (from 902 +/- 297 to 447 +/- 130 ml; mean +/- SD), sodium excretion (from 150 +/- 33 to 89 +/- 35 mEq/12 h), noradrenaline excretion (from 95 +/- 101 to 52 +/- 16 micrograms/g creatinine), noradrenaline plasma concentrations (from 325 +/- 96 to 259 +/- 75 pg/ml), ANP plasma concentrations (from 35 +/- 20 to 19 +/- 5 pg/ml) was observed during the night under CPAP application. These data suggest that in OSAS patients the high ANP plasma concentration is responsible for the observed elevated diuresis and sodium excretion. These effects are rapidly reversible, as they are reversed during the first CPAP treated night.
Objective: Duplex ultrasound evaluation of the clinically diagnosed varicose long saphenous vein (LSV). Design: Prospective, single patient group study. Setting: Department of Surgery, University of Ferrara, Italy (teaching hospital). Patients: 378 patients, 509 limbs with primary varicose veins; 94 patients, 103 limbs with a visible, superficial varicose vein trunk on the medial aspect of the thigh. Main outcome measure: Duplex ultrasound detection of a varicose saphenous vein and/or segmental saphenous dilatation and their relationship to saphenous reflux. Results: In 98% of cases the varicose trunk visible in the thigh was demonstrated to be a tributary of the saphenous vein; 34% of the observed saphenous veins exhibited segmental dilatations in the thigh. This finding was related in every case to saphenous vein reflux with high velocity and turbulence ( p < 0.0001). Conclusions: High-resolution ultrasonography demonstrated that when a dilated varicose longitudinal vein trunk is visible and palpable on the medial aspect of the thigh it is most likely to be a tributary rather than the LSV. In addition, a varicose saphenous vein along its entire length essentially does not exist. However, when a dilated saphenous segment occurs, it seems to be related to high diastolic flow velocity and turbulence.
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