Effects of tilting on central hemodynamics and homeostatic mechanisms in cirrhosis.
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 A/B/C: 2/13/8) and 14 healthy controls were entered. Measurements of central hemodynamics and activation of SNS and RAAS were taken in the supine position, after 30 degrees head-down tilting, and after 60 degrees 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. -36%, P <.01). Central circulation time increased only in the patients (+30% vs. -1%, 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.
Møller
Søren
S
Department of Clinical Physiology, H:S Hvidovre Hospital, Hvidovre, Denmark. soeren.moeller@hh.hosp.dk
Nørgaard
Annette
A
Henriksen
Jens H
JH
Frandsen
Erik
E
Bendtsen
Flemming
F
D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood; D001794:Blood Pressure; D015740:Calcitonin Gene-Related Peptide / Q000097:blood; D003187:Compliance; D005260:Female; D018475:Head-Down Tilt; D006339:Heart Rate; D006439:Hemodynamics; D006801:Humans; D008104:Liver Cirrhosis, Alcoholic / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D010953:Plasma Volume; D011187:Posture; D012083:Renin / Q000097:blood; D014655:Vascular Resistance
D009320:Atrial Natriuretic Factor; D012083:Renin; D015740:Calcitonin Gene-Related Peptide; D009638:Norepinephrine