Fig. 8. ( A ) Median smooth plots of percentage changes from preoxytocin values in heart rate (HR), mean arterial pressure (MAP), stroke volume (SV), and systemic vascular resistance (SVR), for 20 patients receiving either oxytocin or oxytocin plus phenylephrine. ( B ) Ensembles of cardiac output (CO) changes from preoxytocin values as measured with the LiDCO plus (LiDCO, Cambridge, United Kingdom) and the BioZ (Cardio Dynamics International, San Diego, CA) monitors. Each ensemble shows the percentage change for each patient ( light gray ) and the median smooth for the group (black) for the 150 s after administration of either oxytocin or a mixture of oxytocin and phenylephrine.