[Increase in absolute atmospheric pressure in hyperbaric chamber in cirrhosis with ascites: lack of natriuretic response and increase of atrial natriuretic peptide].

In normal subjects increasing atmospheres of absolute pressure (ATA) on the cardiopulmonary system, in a hyperbaric chamber, results in a marked diuresis and an increase of circulating concentration of atrial natriuretic peptide (ANP). The present investigation was designed to determine the effect of ATA in a group of 5 sodium-retaining cirrhotic patients on hydro-saline balance, renin-angiotensin-aldosterone system and ANP. After seven days on a 10 mEq sodium intake, each patient was studied on both a control and experimental (4-hour stay at 2-ATA in hyperbaric chamber) day. On each day, measurement of the following were obtained: plasma ANP, plasma renin activity (PRA) and aldosterone, electrolytes, creatinine clearance, volume and sodium and potassium urinary excretion. The increasing ATA lacked to induce both diuresis, natriuresis and increase in ANP plasma concentration. In these patients baseline, pre-hyperbaric, mean levels of PRA, aldosterone and ANP were 15.5 +/- 11.5 ng/ml/h, 808.4 +/- 360 pg/ml, 86 +/- 10.1 pg/ml, respectively, and were significantly elevated compared with normal range for control subjects without sodium restriction. In conclusion, increasing pressure at 2-ATA, in a hyperbaric chamber is unable to elicit both diuresis and natriuresis as well as modification on ANP and renin-angiotensin-aldo-sterone system in sodium-retaining cirrhotic patients.