A Comparison of Intermittent Intravenous Boluses of Phenylephrine and Norepinephrine to Prevent Spinal-induced Hypotension in Cesarean Deliveries
- Registration Number
- NCT02962986
- Lead Sponsor
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital
- Brief Summary
Hypotension is a very common complication of spinal anesthesia for cesarean delivery, and can have unwanted side effects on both mother and fetus if not treated promptly. Phenylephrine has been the drug of choice to treat this spinal-induced hypotension. Although phenylephrine is safe to use for this indication, it has been associated with reflex bradycardia and a reduction in cardiac output.
Norepinephrine is a potent vasopressor used to treat hypotension in the critical care setting. Recent studies have looked at norepinephrine's use in the obstetric setting, and have shown that it can be used safely and also has favourable hemodynamic properties when compared to phenylephrine, with less bradycardia and less depression of cardiac output.
The investigators recently conducted a study to determine the ED90 of norepinephrine, and now plan to compare bolus doses of phenylephrine to norepinephrine for treating hypotension following spinal anesthesia for cesarean section.
The investigators hypothesize that norepinephrine, when given as a bolus to prevent post spinal hypotension, will result in around 70% relative decrease in the rate of bradycardia when compared to phenylephrine in patients undergoing elective cesarean delivery under spinal anesthesia.
- Detailed Description
Norepinephrine is a potent vasopressor used to treat hypotension in the critical care setting. Recent studies have looked at norepinephrine's use in the obstetric setting, and have shown that it can be used safely and also has favourable hemodynamic properties when compared to phenylephrine, with less bradycardia and less depression of cardiac output. These studies have been limited to using norepinephrine as an infusion and there is limited data with it being used as a bolus to prevent hypotension. A recent study was undertaken at Mount Sinai hospital to determine the ED90 of norepinephrine to treat post spinal hypotension. Secondary outcome data from this trial showed that the incidence of bradycardia associated with this treatment is approximately 7.5%, several times less when compared to the reported 30% with phenylephrine. It would therefore be prudent at this stage to undertake a randomized trial comparing the hemodynamic profile of phenylephrine (our standard practice) and norepinephrine used as intermittent boluses to prevent hypotension and avoid decrease in heart rate during cesarean delivery.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- Female
- Target Recruitment
- 112
- Informed consent
- Elective CS under spinal anesthesia
- Normal singleton pregnancy beyond 36 weeks gestation
- ASA physical status 2-3
- Current (pregnant) weight 50-100 kg, height 150-180 cm
- Age over 18 years
- Patient refusal
- Inability to communicate in English
- Allergy or hypersensitivity to phenylephrine
- Preexisting or pregnancy-induced hypertension
- Cardiovascular or cerebrovascular disease
- Fetal abnormalities
- History of diabetes, excluding gestational diabetes
- Contra-indications for spinal anesthesia
- Allergy or hypersensitivity to sulfite
- Use of monoamine oxidase inhibitors, triptyline or imipramine antidepressants
- Untreated hyperthyroid patients
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description phenylephrine 100mcg Phenylephrine phenylephrine, given as 1mL IV boluses, to treat post-spinal hypotension norepinephrine 6mcg Norepinephrine norepinephrine, given as 1mL IV boluses, to treat post-spinal hypotension
- Primary Outcome Measures
Name Time Method Bradycardia: Heart rate less than 50 bpm 30 minutes Heart rate less than 50 bpm, from induction of spinal anesthesia
- Secondary Outcome Measures
Name Time Method Hypotension: Systolic blood pressure less than 80% of baseline 30 minutes Systolic blood pressure below 80% of baseline, from induction of spinal anesthesia to delivery of the fetus.
Presence of nausea 30 minutes Presence of nausea in patients from induction of spinal anesthesia to delivery of the fetus.
Number of hypotensive episodes 30 minutes The number of times the systolic blood pressure measures below 80% of baseline, from induction of spinal anesthesia to delivery of the fetus.
Umbilical artery base excess (mmol/L) 24 hours Umbilical artery base excess
Hypertension: Systolic blood pressure at or above 120% of baseline 30 minutes Systolic blood pressure at or above 120% of baseline, from induction of spinal anesthesia to delivery of the fetus.
Presence of vomiting 30 minutes Presence of vomiting in patients from induction of spinal anesthesia to delivery of the fetus.
Umbilical artery partial pressure of carbon dioxide 24 hours Umbilical artery partial pressure of carbon dioxide
Umbilical vein base excess (mmol/L) 24 hours Umbilical vein base excess
Tachycardia: Heart rate greater than 30% of baseline 30 minutes Heart rate greater than 30%, from induction of spinal anesthesia to delivery of the fetus.
Number of episodes of nausea 30 minutes The number of episodes of nausea experienced by patients from induction of spinal anesthesia to delivery of the fetus.
Number of episodes of vomiting 30 minutes The number of episodes of vomiting experienced by patients from induction of spinal anesthesia to delivery of the fetus.
Total dose of study drug given 30 minutes Total dose of study drug given from induction of spinal anesthesia to delivery of the fetus.
Umbilical artery partial pressure of oxygen 24 hours Umbilical artery partial pressure of oxygen
Umbilical artery bicarbonate (mmol/L) 24 hours Umbilical artery bicarbonate
Umbilical vein bicarbonate (mmol/L) 24 hours Umbilical vein bicarbonate
Apgar scores 1 minute and 5 minutes The Apgar scores of the infant at 1 and 5 minutes post delivery.
Umbilical artery pH 24 hours Umbilical artery pH
Umbilical vein pH 24 hours Umbilical vein pH
Umbilical vein partial pressure of carbon dioxide 24 hours Umbilical vein partial pressure of carbon dioxide
Umbilical vein partial pressure of oxygen 24 hours Umbilical vein partial pressure of oxygen
Trial Locations
- Locations (1)
Mount Sinai Hospital
🇨🇦Toronto, Ontario, Canada