Ephedrine vs Phenylephrine - ECG Changes
- Conditions
- Spinal AnesthesiaPregnancy
- Interventions
- Registration Number
- NCT01243970
- Lead Sponsor
- University College London Hospitals
- Brief 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 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.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- TERMINATED
- Sex
- Female
- Target Recruitment
- 29
- Able to give written informed consent
- >37/40 weeks gestation
- Singleton pregnancy
- Elective caesarean section under spinal anaesthesia
- 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 )
- Circulatory disease (eg pre-existing hypertension)
- Cardiac disease/medications (e.g. angina, cardiomyopathy, B Blocker medication)
- Pregnancy related disease (eg pre-eclampsia)
- Diabetes pre-existing the pregnancy
- Hyperthyroidism
- Renal Disease
- Closed-angle glaucoma
- Patients on monoamine oxidase inhibitors
- In active labour
- Emergency caesarean section
- Fetal abnormalities
- Contraindications to spinal anaesthesia
- Height >6 feet/180cm / Height <5 feet/150cm
- Body mass index (BMI) <19 or >35
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description phenylephrine infusion Phenylephrine - Ephedrine infusion Ephedrine -
- Primary Outcome Measures
Name Time Method ST segment changes on Holter monitoring 30 minutes pre spinal anaesthesia to 4 hours post delivery
- Secondary Outcome Measures
Name Time Method Maternal cardiac output 20 minutes post spinal and one measure at 5 minutes post delivery Troponin levels 24h post delivery Incidence of maternal low systolic blood pressure 20 minutes post spinal and 30 minutes post delivery
Trial Locations
- Locations (1)
University College London Hospital
🇬🇧London, United Kingdom