Different Approaches to Maternal Hypotension During Cesarean Section

University of Parma

Status and phase: Completed; Phase 4

Conditions: Hypotension; Cesarean Section; Anesthesia,Spinal; Pregnancy

Treatments: Drug: Morphine; Drug: Bupivacaine; Drug: Atropine; Drug: Ephedrine, bolus; Drug: Lactated Ringer's solution; Drug: Ephedrine, continuous infusion

Study type: Interventional

Funder types: Other

Identifiers

NCT00991627

ANEST-OST-02

Details and patient eligibility

About

The aim of this study is to compare two different therapeutic approaches to blood pressure reduction: pharmacological vs. non-pharmacological. The setting is that of patients undergoing scheduled Cesarean section under spinal anesthesia and suffering from aorta-caval compression syndrome, which causes a sudden drop in blood pressure.

Full description

The supine hypotensive syndrome of pregnancy is induced by compression of the inferior caval vein by the enlarged uterus. It occurs in approximately 8% of pregnant women at term. More patients may develop an asymptomatic variety of this syndrome in the supine position. The hypotensive effect of spinal anesthesia per se may thus be aggravated in a significant number of term parturients. A preoperative supine stress test (SST) before elective cesarean section under spinal anesthesia has been shown to predict severe systolic hypotension with reasonable accuracy.

Different strategies have been proposed for the management of this complication; they can be divided into pharmacological and non-pharmacological ones.

According to pharmacological strategies, vasoactive drugs are used to treat hypotension induced by sympathetic efferent blockade following spinal anesthesia. To this end, α-agonist ephedrine is commonly considered the best choice because of its minimal impact on the fetoplacental circulation. However, excessive use of ephedrine may be detrimental to neonatal well-being because of its vasoconstrictor effect on fetoplacental circulation.

Non-pharmacological treatments may represent a valuable, safer alternative. According to many authors non-pharmacological treatments aimed at removing the cause of aorta-caval compression syndrome are to be preferred because more appropriate from an etiopathogenetic point of view. The use of a wedge-shaped cushion placed under the right hip is a well-known non-pharmacological strategy which allows the uterine left lateral displacement and, consequently, the removing of the compression from the inferior vena cava.

The aim of the present study is to compare, through the evaluation of neonatal well-being, the efficacy of these approaches to hypotension after spinal anesthesia for elective Caesarean section in parturients affected by aorto-caval compression.

Enrollment: 36 estimated patients

Sex: Female

Ages: 18 to 50 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Patients undergoing spinal anesthesia for elective Cesarean section
• Patients in ASA Physical Status Class I or II
• Informed written consent to participation
• Positive Supine Stress Test

Exclusion criteria

• Any known fetal pathology
• Indication to general anesthesia
• Known allergy to any of the study drugs

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Single Blind

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36 participants in 2 patient groups

Pharmacological

Active Comparator group

Description:

Patients in this group will receive a basal infusion of ephedrine. Hypotension will be treated for a reduction in systolic blood pressure 20% below baseline values.

Treatment:

Drug: Ephedrine, bolus

Drug: Lactated Ringer's solution

Drug: Atropine

Drug: Bupivacaine

Drug: Ephedrine, continuous infusion

Drug: Morphine

Non-Pharmacological

Experimental group

Description:

Patients in this group will undergo uterine lateral displacement through the use of a wedge-shaped cushion placed under their right hip. Hypotension will be treated for a reduction in systolic blood pressure 40% below baseline values.

Treatment:

Drug: Ephedrine, bolus

Drug: Lactated Ringer's solution

Drug: Atropine

Drug: Bupivacaine

Drug: Morphine