THE HYPERVENTILATION OF CIRRHOSIS - PROGESTERONE AND ESTRADIOL EFFECTS

Progesterone and estradiol are metabolized in the liver and are elevat ed in patients with cirrhosis. Progesterone stimulates ventilation by activating progesterone receptors in the central nervous system; estra diol may facilitate progesterone's actions by increasing progesterone receptors. This study evaluated whether progesterone and estradiol con tribute to the respiratory alkalosis common in cirrhotic patients. Art erial blood gases and progesterone and estradiol levels were obtained in 50 patients with cirrhosis. Multiple linear regression revealed a s tatistically significant correlation between PaCO2 and progesterone an d estradiol (r = .54, P < .05). Patients with severe hyperventilation (PaCO2 less than or equal to 30 mm Hg) had statistically higher levels of progesterone and estradiol than did patients with mild hyperventil ation (30 < PaCO2 less than or equal to 35) or normal ventilation (PaC O2 > 35) (P < .05). Although the progesterone levels were two orders o f magnitude lower than those associated with hyperventilation in pregn ant patients, the increased ventilatory effect may be because of the a ltered blood-brain barrier (BBB) present in cirrhotic patients. Proges terone and estradiol appear to contribute to the hyperventilation in c irrhotic patients.