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Ephedrine vs Phenylephrine - ECG Changes

Information source: University College London Hospitals
ClinicalTrials.gov processed this data on August 23, 2015
Link to the current ClinicalTrials.gov record.

Condition(s) targeted: Spinal Anesthesia; Pregnancy

Intervention: Phenylephrine (Drug); Ephedrine (Drug)

Phase: Phase 4

Status: Not yet recruiting

Sponsored by: University College London Hospitals

Official(s) and/or principal investigator(s):
Roshan Fernando, FRCA, Principal Investigator, Affiliation: University College London Hospital

Overall contact:
Roshan Fernando, FRCA, Phone: 011 44 8451 555 000, Email: r.fernando@btinternet.com


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 influences 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. The investigators 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, the investigators will perform troponin T analysis after delivery. Troponin T is a molecule released by ischaemic heart muscle.

Clinical Details

Official 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

Study design: Allocation: Randomized, Endpoint Classification: Safety Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Treatment

Primary outcome: ST segment changes on Holter monitoring

Secondary outcome:

Troponin levels

Incidence of maternal low systolic blood pressure

Maternal cardiac output


Minimum age: 16 Years. Maximum age: N/A. Gender(s): Female.


Inclusion Criteria: 1. Able to give written informed consent 2. >37/40 weeks gestation 3. Singleton pregnancy 4. Elective caesarean section under spinal anaesthesia 5. In good general health (American Society of Anesthesiology Category 1 or 2, fit and well or with mild systemic disease that has no impact on physical activity ) Exclusion Criteria: 1. Circulatory disease (eg pre-existing hypertension) 2. Cardiac disease/medications (e. g. angina, cardiomyopathy, B Blocker medication) 3. Pregnancy related disease (eg pre-eclampsia) 4. Diabetes pre-existing the pregnancy 5. Hyperthyroidism 6. Renal Disease 7. Closed-angle glaucoma 8. Patients on monoamine oxidase inhibitors 9. In active labour 10. Emergency caesarean section 11. Fetal abnormalities 12. Contraindications to spinal anaesthesia 13. Height >6 feet/180cm / Height <5 feet/150cm 14. Body mass index (BMI) <19 or >35

Locations and Contacts

Roshan Fernando, FRCA, Phone: 011 44 8451 555 000, Email: r.fernando@btinternet.com

University College London Hospital, London NW1 2BU, United Kingdom; Not yet recruiting
Roshan Fernando, FRCA, Phone: 011 44 8451 555 000, Email: r.fernando@btinternet.com
Additional Information

Last updated: December 2, 2010

Page last updated: August 23, 2015

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