Related Experiment Videos
Estimated central blood volume in cirrhosis: relationship to sympathetic nervous activity, beta-adrenergic blockade
J H Henriksen1, F Bendtsen, A L Gerbes
1Department of Clinical Physiology, Hvidovre Hospital, University of Copenhagen, Denmark.
Insights
In cirrhosis patients, higher sympathetic nervous activity correlated with lower central blood volume. Beta-blocker treatment did not significantly alter central blood volume but affected blood pressure and atrial pressure.
Area of Science:
- Cardiovascular Physiology
- Hepatology
- Renal Physiology
Background:
- Cirrhosis is associated with complex hemodynamic alterations and neurohormonal dysregulation.
- Understanding the relationship between central blood volume and sympathetic nervous activity is crucial in managing cirrhotic patients.
Purpose of the Study:
- To investigate the correlation between estimated central blood volume and sympathetic nervous activity in patients with cirrhosis.
- To assess the impact of beta-adrenergic blockade on central blood volume and related hemodynamic parameters.
Main Methods:
- Estimated central blood volume was calculated by multiplying cardiac output by mean transit time.
- Sympathetic nervous activity was assessed using arterial and renal venous norepinephrine levels.
- Hemodynamic parameters were measured before and after administration of oral propranolol.
Main Results:
- Arterial and renal venous norepinephrine levels, indicators of sympathetic activity, were significantly higher in cirrhosis patients compared to controls.
- A negative correlation was observed between sympathetic nervous activity and estimated central blood volume in patients with cirrhosis.
- Beta-adrenergic blockade with propranolol did not significantly alter mean central blood volume, but decreased blood pressure and central blood volume in a subset of patients.
Conclusions:
- Sympathetic nervous system overactivity in cirrhosis is associated with a reduced central blood volume.
- Beta-blockade may influence central blood volume and arterial pressure, particularly in hemodynamically compromised cirrhotic patients.
- Atrial natriuretic factor levels did not show a significant correlation with central blood volume in this patient cohort.
Abstract:
The estimated central blood volume (i.e., blood volume in the heart cavities, lungs and central arterial tree) was determined by multiplying cardiac output by circulatory mean transit time in 19 patients with cirrhosis and compared with sympathetic nervous activity and circulating level of atrial natriuretic factor. Arterial norepinephrine level, an index of overall sympathetic nervous activity (3.08 nmol/L in patients vs. 1.36 nmol/L in controls; p < 0.01) was negatively correlated (r = -0.54, p < 0.01) with estimated central blood volume (mean = 23 ml/kg in patients vs. 27 ml/kg in controls; p < 0.05). Similarly, renal venous norepinephrine level (an index of renal sympathetic tone; 4.26 nmol/L in patients vs. 1.78 nmol/L in controls; p < 0.01) was inversely correlated with estimated central blood volume (r = -0.53, n = 18, p < 0.02). No significant correlation could be established between arterial atrial natriuretic factor level (8.9 pmol/L in patients vs. 9.6 pmol/L in controls; not significant) and estimated central blood volume. Hemodynamic values were subsequently modified with oral propranolol (80 mg). During beta-adrenergic blockade, the mean estimated central blood volume was not altered significantly, except in six patients who exhibited decreases in mean arterial blood pressure (85 to 69 mm Hg; n = 6) and decreases in mean estimated central blood volume (23.2 to 20.6 ml/kg; n = 6, p < 0.05). Slight increases were observed in mean right atrial pressure (2.2 to 3.7 mm Hg; n = 14, p < 0.05); this change was positively correlated with the change in estimated central blood volume (r = 0.44, n = 14, p = 0.06).(ABSTRACT TRUNCATED AT 250 WORDS)