Roy L, Ramanathan S
Department of Anesthesiology, Magee-Womens Hospital, University of Pittsburgh School of Medicine, PA 15044 USA.
Can J Anaesth. 1999 Jan;46(1):52-5. doi: 10.1007/BF03012515.
To evaluate myocardial contractility during ST segment depression in healthy parturients during Cesarean section (CS).
Forty-seven consecutive term parturients undergoing elective CS under spinal anesthesia were studied. The ST segment was recorded continuously on leads II and V5 using a Holter monitor. Myocardial performance was evaluated by measuring cardiac index (CI), heart rate (HR), pre-ejection period (PEP), ventricular ejection time (VET), systolic time ratio (STR, PEP/VET), and ejection fraction (EF) with an impedance cardiograph.
Fourteen patients (30%) developed ST segment depression within 15 min after delivery and the remaining 33 (70%) did not (controls). Seven patients developed a 1 mm change, five patients a 2 mm change and the remaining two a 3 mm change in the ST segment. Compared with pre-anesthesia values, the mean HR increased from 103 +/- 10 to 116 +/- 10 (ISD) bpm (P = 0.001), CI from 4.7 +/- 0.7 to 5.6 +/- 1.7 L.min-1 (P = 0.01), EF from 0.58 +/- 0.08 to 0.66 +/- 0.05 (P = 0.01) and STR decreased from 0.26 +/- 0.06 to 0.2 +/- 0.04 (P = 0.01) during ST segment depression. At this time, CI, HR and EF were greater and STR smaller than values obtained 15 min after delivery in the control subjects.
ST-segment depression occurring during CS is associated with a hyperkinetic myocardial contractile state.
