Assessment of total vascular resistance and total body water in normotensive women during the first trimester of pregnancy. A key for the prevention of preeclampsia.

INTRODUCTION: Maternal cardiovascular system adapts to pregnancy, thanks to complex physiological mechanisms that involve cardiac output, total vascular resistance and water body distribution. Abnormalities of these adaptive mechanisms are connected with hypertensive disorders. OBJECTIVE: To identify patients at a high risk of developing hypertensive complications of pregnancy during the first trimester of pregnancy, through the use of non-invasive methods such as USCOM (Ultrasonic Cardiac Output Monitor) and Bioimpedance. MATERIALS AND METHODS: We enrolled 120 healthy normotensive women during the first trimester of pregnancy obtaining all measurements with the USCOM system and Bioimpedance. RESULTS: 20 patients were excluded for a bad USCOM signal. The remaining patients (n = 100) were retrospectively divided into two groups: Group A (n = 75) TVR<1200 dynes s cm(-5), Group B (n = 25) TVR>1200 dynes s cm(-5). No statistically significant difference was identified in terms of water distribution, Fat Free Mass, Systolic/Diastolic Blood Pressure, Heart Rate, Hematocrit, Flow Time Corrected and Water Balance Index between the two groups. In contrast, higher values of the Cardiac Output, Stroke Volume, Fat Mass and Inotropy Index have been highlighted in the Group A. Moreover, in the Group A we found a better maternal-neonatal outcome and a lower incidence of hypertensive complications. CONCLUSIONS: High TVR during the first weeks of gestation may be an early marker of cardiovascular maladaptation more than the evaluation of water distribution and, in particular, with respect to the single blood pressure assessment. Moreover lower values of Inotropy Index could be an indicative of the worst cardiac performance.

The maternal cardiovascular effect of carbetocin compared to oxytocin in women undergoing caesarean section.

OBJECTIVE: To compare haemodynamic changes, measured noninvasively using the USCOM monitor, after combined spino-epidural anaesthesia and after administration of two different uterotonic drugs, oxytocin and carbetocin, in a population of pregnant women during elective caesarean delivery. METHODS: Haemodynamic measurements were obtained with the USCOM system, by positioning a probe at maternal suprasternal notch (SSN) until the aortic valve flow's profile was optimally identified. Evaluations of the haemodynamic profile were obtained in seven different moments: before anaesthesia; during skin incision; 60, 180 and 300s after administration of uterotonic drug, at closure of the uterus, at closure of the skin. Doses of uterotonic drugs were: Oxytocin 5UI in 500cc NaCl eV, Carbetocin 100mcg in bolus eV. Main measured parameters were: heart rate, mean blood pressure, stroke volume, cardiac output and total vascular resistance. RESULTS: We enrolled 32 pregnant women. Patients were randomized in two groups: oxytocin and carbetocin. A reduction in mean blood pressure, a reduction of total vascular resistance and an increase of cardiac output and of stroke volume were seen, while heart rate values remained stable in both treatment groups. No statistically significant differences were found. DISCUSSION: Administration of carbetocin is associated with a substantial global haemodynamic stability in patients undergoing elective caesarean section without any difference with oxytocin. This observation allows us to consider carbetocin comparable to oxytocin, with minimum haemodynamic impact on the maternal circulation. This minimal effect on global haemodynamic stability might extend the use of this uterotonic drug in patients at high haemorrhagic risk with preeclampsia.