P4.02 EFFECTS OF TOCOLYTICAL MEDICATION ON BLOOD PRESSURE AND BLOOD PRESSURE AMPLIFICATION

Abstract

Objective: Atosiban (oxytocin-antagonist) and ritodrine (β-agonist) are frequently used tocolytics. Only a few studies investigated the hemodynamic effects of atosiban. We therefore aimed to study the effects on the blood pressure (BP) and BP-amplification. 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 brachial artery (BA) blood pressures (BP) were taken by an oscillometric device (OMRON 705-IT) and the BP at the common carotid artery (CCA) and the radial artery (RA) were calculated using applanation tonometry. This was done at the steady state of the highest dose. Statistical analysis was done using Friedman and Wilcoxon test setting value of significance at 0.05. Results: Effects on atosiban/placebo on N=20 did not differ from N=8. Parameters (mmHg) Ritodrine (n=8) Atosiban (n=8) Placebo (n=8) p-value$ SBPCCA 113±13*# 105±10 100±6 0.012 SBPBA 114±13*# 106±10 103±6 0.004 SBPRA 115±15*# 110±13 110±7 0.368 DBPBA 55±11*# 69±6 68±5 0.008 MAP 76±10*# 84±8 82±6 <0.001 SBP (systolic BP), DBP (diastolic BP), MAP (mean arterial pressure). $Friedman-test; *significant vs. atosiban, #significant vs. placebo. Conclusion: The data show increased SBP at the CCA and BA and lower DBP and MAP under ritodrine. The effects of atosiban did not differ from placebo. Although not statistically significant, the data suggest a nearly absent pressure amplification between CCA-RA during ritodrine administration.