Ephedrine vs phenylephrine – ECG changes. V1
Research type
Research Study
Full title
Randomised, double blind, phase IV study to compare the incidence of ECG changes during elective caesarean section under spinal anaesthesia when using phenylephrine or ephedrine infusion to maintain baseline systolic blood pressure
IRAS ID
8865
Contact name
Roshan Fernando
Sponsor organisation
Joint UCLH/UCH Biomedical Research Unit
Eudract number
2009-013293-41
Clinicaltrials.gov Identifier
Research summary
ECG changes during caesarean section are common. Incidence of ST depression on the ECG is up to 81% in some studies. Although this may indicate inadequate oxygen supply to the heart muscle (myocardial ischaemia) many other theories have been suggested including air entering the circulation from the placental bed, high heart rate, hormone or nervous system flunces and spasm of the coronary blood supply. Perioperative ST depression often reflects an imbalance between heart muscle oxygen supply and demand. At the time of delivery, high heart rate is common and there is a further increase in the amount of blood the heart has to pump every minute due to blood coming back to the circulation from the placental bed. This increases oxygen demand and most ST changes are seen at the time of delivery or within 30 minutes. The clinical significance of these changes is much debated, and apart from a few case reports do not appear to be associated with poor heart muscle function or ischaemia (lack of oxygen supply). Management of the mother's blood pressure during caesarean section has changed greatly in recent years. Intermittent boluses of ephedrine, given when blood pressure is low, have been replaced with prevention of low blood pressure and phenylephrine has become the drug of choice. Ephedrine increases heart rate and contractility of the heart muscle and is likely to increase oxygen demand. Phenylephrine reduces heart rate while maintaining blood pressure which may result in a more favorable oxygen supply demand ratio.We aim to compare the incidence of ECG changes if the mother's blood pressure is maintained with phenylephrine as compared to ephedrine. To see if these ECG changes are associated with myocardial ischaemia, we will perform troponin T analysis after delivery. Troponin T is a molecule released by ischaemic heart muscle.
REC name
London - Bloomsbury Research Ethics Committee
REC reference
10/H0713/89
Date of REC Opinion
21 Mar 2011
REC opinion
Further Information Favourable Opinion