Non-Invasive Bioimpedence Monitor Use in Obstetric Patients Undergoing Spinal Anesthesia for Cesearean Section

Background: Hypotension during spinal anesthesia remains a common clinical issue, particularly during Cesarean sections and can lead to adverse maternal or neonatal outcomes. ASA standard monitoring of heart rate (HR) and blood pressure (BP) are common maternal variables monitored throughout C-sections as surrogate markers for maternal cardiac output (CO), which more directly reflects uteroplacental perfusion Methods: Here we present the first description of bioreactancenon invasive cardiac monitor (NICOMTM) use in a series of healthy parturients undergoing elective Cesarean section under spinal anesthesia, a monitor that is now routinely used at our institution in the obstetric operating room. Results: There was a very significant decrease in both SBP and DBP and increase in HR (p<0.001) after spinal anesthesia placement, however there was no significant change in the CO, CI or SVI (p>0.05) during that same period. This change was maximal at 1 and 2 minutes after spinal anesthesia respectively for HR and blood pressure. In contrast after delivery of the fetus there were no significant changes in SBP, DBP and HR (p>0.05), but a dramatic increase in CO (22.5%), CI (16.3%) as well as SVI (13.6%). There were no further changes to any of these parameters at delivery of the placenta; however there was maintenance of the elevated cardiac output and stroke volume index compared to the base line at the time of the spinal placement. Conclusion: While transient maternal hypotension does not seem to result in adverse short term neonatal outcome, it would be ideal to maintain maternal cardiac output for both maternal and fetal reasons. Routine use of NICOM in all C-section patients should be considered, particularly in high risk obstetric patients where early intervention for developing hypotension and more importantly reduced cardiac output, is critical.