Patients with cirrhosis have a hyperdynamic circulation and an abnormal blood volume distribution with central hypovolemia, an activated sympathetic nervous system (SNS) as well as the renin-angiotensin-aldosterone system (RAAS). As the hyperdynamic circulation in cirrhosis may be present only in the supine patient, we studied the humoral and central hemodynamic responses to changes with posture. Twenty-three patients with alcoholic cirrhosis (Child-Turcotte-Pugh classes AIBIC: 21 1318) and 14 healthy controls were entered.
Measurements of central hemodynamics and activation of SNS and RAAS were taken in the supine position, after 30" head-down tilting, and after 60" passive head-up tilting for a maximum of 20 minutes. After the head-up tilting, the central blood volume (CBV) decreased in both groups, but the decrease was significantly smaller in patients than in controls (-19% vs. -36Y0, P < .01). Central circulation time increased only in the patients (+30% vs. -lYo, P < .01). The absolute increases in circulating norepinephrine and renin after head-up tilting were significantly higher in the patients than in the controls (P < .05 and P < .01, respectively). In patients with cirrhosis, changes in SNS and RAAS were related to changes in arterial blood pressure, systemic vascular resistance, heart rate, non-CBV, plasma volume, and arterial compliance. In conclusion, cardiovascular and humoral responses to changes in posture are clearly abnormal in patients with cirrhosis. Head-up tilting decreases the CBV less in patients with cirrhosis, and the results suggest a differential regulation of central hemodynamics in patients with cirrhosis. (HEPATOLOGY 2004;40:8 11-819.) atients with advanced cirrhosis present with a hyperdynamic circulation with reduced systemic vas-P cular resistance (SVR) and increased arterial compliance (AC). l x 2 Excess of vasodilators leads to the development of a hyperdynamic but hyporeactive circulation, despite activation of vasoconstrictive counter-regulatory mechanisms.3~4 In the supine position, the distribution of the blood volume is abnormal with relatively reduced central blood volume (CBV) and expanded noncentral blood and plasma volumes.3,5,6 Central hypo-