Norepinephrine for Hypotension in Cesarean Section

Study Overview
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Brief Summary
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Hypotension is a very common consequence of the sympathetic vasomotor block caused by spinal anesthesia for cesarean section. Maternal symptoms such as nausea, vomiting and dyspnea frequently accompany severe hypotension, and adverse effects on the fetus, including depressed APGAR scores and umbilical acidosis, have been correlated with severity and duration of hypotension. Because hypotension is frequent, vasopressors should be used routinely and preferably prophylactically.

Detailed Description
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Phenylephrine has a potent direct α effect, with virtually no β effects at clinical doses, however when given at higher than required doses, it may induce baroreceptor-mediated bradycardia with a consequent reduction in maternal cardiac output. Although α agonist drugs are the most appropriate agents to treat or prevent hypotension following spinal anaesthesia, those with a small amount of β agonist activity may have the best profile (noradrenaline (norepinephrine) and metaraminol. Phenylephrine is currently recommended due to the amount of supporting data.Noradrenaline is the primary catecholamine released by postganglionic adrenergic nerves. It is a potent α adrenergic agonist, with comparatively modest β agonist activity.

Official Title
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Norepinephrine or Phenylephrine for Hypotension in Non-elective Cesarean Section

Conditions
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Hypotension, Cesarean Section

Intervention / Treatment
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* Drug: Norepinephrine
* Drug: Phenylephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who fall in category 2 and 3 according to the classification of Caesarean section made by Royal College of Obstetrician and Gynaecologists. Exclusion Criteria: Patient refusal either to study enrollment or to spinal anesthesia. Any absolute contraindication to spinal anesthesia e.g. coagulopathy, skin infection at site of injection. Allergy to any of study drugs. Patients with cardiac morbidities, hypertensive disorders or peripartum bleeding BMI > 40 kg/m² Baseline systolic blood pressure < 100 mmHg.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: NEP group<br>Norepinephrine infusion of 0.025 µg/kg/min and 6 µg bolus will be used if BP is reduced 20 % below baseline. | Drug: Norepinephrine<br>* prophylaxis for hypotension<br>* Other names: noradrenaline;|
| Placebo Comparator: PHE group<br>Phenylephrine will be started at 25µg/min immediately after the intrathecal local anaesthetic injection and titrated according to blood pressure and pulse rate. | Drug: Phenylephrine<br>* standerd prophylaxis for hypotension<br>* Other names: phenylephrine hydrochloride;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of hypotensive episodes. | Hypotension is defined as <80% of baseline or systolic blood pressure (SBP) <100 mmHg. | 15-20 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of maternal bradycardia. | Bradycardia is defined as heart rate (HR) < 50 beats/min | 15-20 minutes | 
| Incidence of reactive hypertension | defined as >120% of baseline. | 20 minutes | 
| nausea and vomiting | Incidence of nausea and vomiting attacks. | 20 minutes | 
| Total dose of vasopressor | Total dose of vasopressor used. | 20 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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post spinal anesthesia