Effects of normobaric hyperoxia on haemodynamic parameters of healthy full-term parturients.

Fifteen healthy, full-term women with singleton pregnancies were exposed to an increased F(I)o(2) of 0.4 and their haemodynamic responses measured with a non-invasive transthoracic bio-impedance monitor. There was a mean reduction in cardiac index from 3.18 to 3.03 l x min(-1) x m(-2) (4.7%, p = 0.004). The mean indexed systemic vascular resistance increased from 2049 to 2178 dynes x cm(-5) x m(-2) (5.7%, p = 0.005). There were no significant changes in stroke index, heart rate or mean arterial pressure. This study demonstrates that even a moderate increase in inspired oxygen fraction has significant effects on the cardiovascular system of the term parturient.