Phenylephrine for Spinal Induced Hypotension

IWK Health Centre66 enrolled

Overview

This study is designed to determine the ED90 for a single dose of phenylephrine for the treatment of spinal induced hypotension in parturients presenting for an elective CD. The ED90 is the effective dose at which 90% of subjects will have a "positive" response to phenylephrine. The primary outcome measure is the ED90 for bolus phenylephrine. Secondary outcomes include the need for additional vasopressors, glycopyrolate to treat bradycardia, and the presence of hypertension following administration of phenylephrine.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

QUADRUPLE

Enrollment

Conditions

Hypotension

Interventions

Phenylephrine bolusDRUG

The initial dose of phenylephrine will be 100 mcg, a dose within the clinical range currently in use at our center. The subsequent dose is based upon the response of the preceding subject in the usual up-and-down method (UDM), which is outlined in the "data analysis" section of the protocol. The dosing changes will be in increments of 20 micrograms. A successful response to this dose will be entered into a spreadsheet, designed by our statistician, which will determine the subsequent dose based upon the UDM. If a failure is observed in the previous subject, the dose is stepped up in the next subject. If a success is observed the next subject is randomized with probability of 0.10 to the next lower dose and with probability 0.90 to the same dose.

Eligibility

Sex: FEMALEMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Non-emergent cesarean delivery with planned regional anesthesia (i.e. elective planned cesarean delivery for malposition, patient choice, cervical pelvic disproportion, previous cesarean delivery and other diagnosis that require a predetermined cesarean delivery) 2. American Society of Anesthesia physical status class I \& II (ASA I - Healthy, ASA II - mild and controlled systemic disease, eg. controlled essential hypertension) 3. Age ≥ 18 years (Standard within the obstetrical literature) 4. Term gestational age 5. English-speaking Exclusion Criteria: 1. Morbid Obesity (Body Mass Index ≥ 45 kg/m2) (Morbidly obese parturients require a dose of local anesthetic less than the standardized dose in this study, typically have an exaggerated response to vasopressors, and the blood pressure cuff occasionally needs to be replaced by an intraarterial catheter due to limitations in size) 2. Height \< 5'0" (Women \< 5'0" are likely to require a dose of local anesthetic less than the standardized dose in this study) 3. Laboring women 4. Urgent or emergency cesarean delivery 5. Severe hypertensive disease of pregnancy defined as systolic blood pressure (SBP) \> 160mmHg, diastolic blood pressure (DBP) \> 110mmHg and/or requiring antihypertensive treatment or associated with significant proteinuria 6. Severe maternal cardiac disease 7. Diabetes type I 8. Subjects on monoamine oxidase inhibitors (MAOI's) or tricyclic antidepressants 9. Fetal anomalies 10. Failed spinal anesthesia 11. Subject enrollment in another study involving a study medication within 30 days of CD 12. Any other physical or psychiatric condition which may impair their ability to cooperate with study data collection

Locations (1)

IWK Health Centre

Halifax, Nova Scotia, Canada

Outcomes

Primary Outcomes

The primary outcome measure is the ED90 for bolus phenylephrine.

Time frame: Intraoperative

Secondary Outcomes

Secondary outcomes include the need for additional vasopressors, glycopyrolate to treat bradycardia, and the presence of hypertension following administration of phenylephrine.

Time frame: Intraoperative

Data from ClinicalTrials.gov

This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.