P4.01 EFFECTS OF TOCOLYTICAL MEDICATIONS ON THE PERIPHERAL AND CENTRAL HEMODYNAMICS OF HEALTHY FEMALE VOLUNTEERS

Abstract

Objective: Atosiban and ritodrine are frequently used tocolytics. Only a few studies investigated the hemodynamic effects of atosiban. We therefore aimed to study the central and peripheral hemodynamics of both medications. Methods: Twenty healthy female volunteers (19–41 yrs) were given atosiban (300 μg/min over 2h) and placebo intravenously (IV) in a random crossover design. Eight of them also received ritodrine IV in escalating doses up to 400μg/min over 2h. The hemodynamics were investigated at steady state using blood pressure (BP) at the brachial artery (BA), pulse wave analysis on the common carotid artery and echocardiography for cardiac output (CO). Statistical analysis was done using Friedman and Wilcoxon tests (value of significance at 0.05). Results: Effects on atosiban/placebo on N=20 did not differ from N=8. Parameters Ritodrine (n=8) Atosiban (n=8) Placebo (n=8) p-value$ CI (l/min/m2) 3.15±0.92*# 1.91±0.47 1.75±0.36 0.002 SI (ml/m2) 28.19±6.34*# 32.47±7.07 30.40±4.27 0.325 HR (bpm) 111±20*# 59±10 57±9 0.002 TPRI (mmHg.ml−1.s) 1.53±0.48*# 2.69±0.85 2.93±0.66 0.005 MAP(mmHg) 76±10*# 84±8 82±6 <0.001 AGPP (mmHg) −8.67±12.30 2.29±17.35 4.38±13.67 0.368 CI (cardiac index); SI (stroke index); MAP (mean arterial pressure); TPRI (total peripheral resistance index); HR (heart rate); AGPP (augmentation index at HR 75). $Friedman-test; *significant vs. atosiban; #significant vs. placebo. Conclusion: Ritodrine has important hemodynamical effects reflected by cardiac stimulation (increase in CI through HR increase) and a decrease in peripheral resistance (TPRI) with a trend for decreasing wave reflections (AGPP). The effect of atosiban on central and peripheral hemodynamics did not differ from placebo.