Vasopressors for Low Blood Pressure

Recruiting in Palo Alto (17 mi)

Overseen by Mrinalini Balki, MD

Age: 18 - 65

Sex: Female

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Academic

Recruiting

Sponsor: Samuel Lunenfeld Research Institute, Mount Sinai Hospital

No Placebo Group

Trial Summary

What is the purpose of this trial?

Hypotension is one of the most common adverse effects of spinal anesthesia for cesarean deliveries, affecting as many as 55-90% of mothers. Hypotension during cesarean deliveries can have detrimental effects on the mother and neonate. Various vasopressors, such as ephedrine, phenylephrine and more recently norepinephrine, have been used for the prevention and treatment of hypotension at cesarean deliveries. Ephedrine was historically considered as the gold standard vasopressor for the management of hypotension during cesarean deliveries. This was based on studies in animal models that showed preserved uteroplacental circulation with ephedrine and not with phenylephrine. However, multiple studies in the past several decades have shown that phenylephrine compared with ephedrine results in a more favorable fetal acid-base status. Consequently, the use of phenylephrine for blood pressure management during cesarean deliveries increased. Recently, norepinephrine was introduced in the obstetrical practice for the management of hypotension at cesarean deliveries, due to its ability to maintain maternal cardiac output better than phenylephrine. Studies have also investigated the use of vasopressin to limit hypotension during CD. There have been case reports of successful vasopressin usage to treat post-spinal hypotension after CD in patients with advanced idiopathic pulmonary arterial hypertension as well as severe mitral stenosis with pulmonary hypertension. Its effect was associated with hemodynamic stability without evidence of harm to the mother or child. However, much controversy still exists surrounding the choice of vasopressor in the obstetric population, in large part due to their varying efficacies, and maternal and fetal effects. Vasopressors used for the treatment of hypotension during cesarean deliveries can have significant direct or indirect effects on the perfusion of uteroplacental and umbilical vessels. Reduction of uteroplacental perfusion and constriction of umbilical vessels can result in fetal acidosis, however, the mechanisms for these effects are unclear. The investigators hypothesize that ephedrine, phenylephrine and norepinephrine and vasopressin have variable effects on the contractility of pregnant myometrium and umbilical arteries due to their variable actions on adrenergic alpha (α) and beta (β) receptors, as well as vasopressin1 and vasopressin2 receptors located in these tissues.

Eligibility Criteria

This trial is for non-laboring patients aged 19-40, undergoing elective primary or first repeat cesarean delivery under spinal anesthesia at a gestational age of 37-41 weeks. They must consent to participate and not have had previous uterine surgery beyond one cesarean, nor be on medications affecting myometrial contractility.

Inclusion Criteria

I am having a C-section with spinal anesthesia.

You are scheduled for your first or repeat caesarean delivery that is not an emergency.

Patients who give written consent to participate in this study

Exclusion Criteria

You have any condition that can lead to weak uterine muscles.

I am taking medication that could affect muscle contractions in my uterus.

I need general anesthesia for my treatment.

Participant Groups

The study tests the effects of vasopressors—Ephedrine, Phenylephrine, Norepinephrine, and Vasopressin—on the muscle contractions of the uterus (myometrium) and umbilical vessels in vitro. It aims to understand how these drugs can manage low blood pressure during cesarean deliveries without harming mother or baby.

Group I: Umbilical vein + Vasopressin Experimental Treatment 1 Intervention

The umbilical vein samples are bathed in physiological salt solution (PSS) with increasing concentrations of vasopressin

Group II: Umbilical vein + Phenylephrine Experimental Treatment 1 Intervention

The umbilical vein samples are bathed in physiological salt solution (PSS) with increasing concentrations of phenylephrine

Group III: Umbilical vein + Norepinephrine Experimental Treatment 1 Intervention

The umbilical vein samples are bathed in physiological salt solution (PSS) with increasing concentrations of norepinephrine

Group IV: Umbilical vein + Ephedrine Experimental Treatment 1 Intervention

The umbilical vein samples are bathed in physiological salt solution (PSS) with increasing concentrations of ephedrine

Group V: Umbilical artery + Vasopressin Experimental Treatment 1 Intervention

The umbilical artery samples are bathed in physiological salt solution (PSS) with increasing concentrations of vasopressin

Group VI: Umbilical artery + Phenylephrine Experimental Treatment 1 Intervention

The umbilical artery samples are bathed in physiological salt solution (PSS) with increasing concentrations of phenylephrine

Group VII: Umbilical artery + Norepinephrine Experimental Treatment 1 Intervention

The umbilical artery samples are bathed in physiological salt solution (PSS) with increasing concentrations of norepinephrine

Group VIII: Umbilical artery + Ephedrine Experimental Treatment 1 Intervention

The umbilical artery samples are bathed in physiological salt solution (PSS) with increasing concentrations of ephedrine

Group IX: Myometrium + Vasopressin Experimental Treatment 1 Intervention

The myometrial samples are bathed in physiological salt solution (PSS) with increasing concentrations of vasopressin

Group X: Myometrium + Phenylephrine Experimental Treatment 1 Intervention

The myometrial samples are bathed in physiological salt solution (PSS) with increasing concentrations of phenylephrine

Group XI: Myometrium + Norepinephrine Experimental Treatment 1 Intervention

The myometrial samples are bathed in physiological salt solution (PSS) with increasing concentrations of norepinephrine

Group XII: Myometrium + Ephedrine Experimental Treatment 1 Intervention

The myometrial samples are bathed in physiological salt solution (PSS) with increasing concentrations of ephedrine

Ephedrine is already approved in United States, Canada for the following indications:

🇺🇸 Approved in United States as Ephedrine for:

• Hypotension
• Bronchial asthma
• Narcolepsy
• Myasthenia gravis
• Allergic disorders

🇨🇦 Approved in Canada as Ephedrine for:

• Nasal decongestant
• Asthma
• Bronchitis

Find a Clinic Near You

Research Locations Nearby Select from list below to view details:

Mount Sinai Hospital Toronto, Canada

Who Is Running the Clinical Trial?

Samuel Lunenfeld Research Institute, Mount Sinai Hospital Lead Sponsor

References