Different Approaches to Maternal Hypotension During Cesarean Section

Pharmacological or Non-Pharmacological Management of Maternal Hypotension During Elective Cesarean Section Under Subarachnoid Anesthesia: a Randomized, Controlled Trial

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.

Study Overview

• Status: Completed
• Conditions: Pregnancy; Hypotension; Cesarean Section; Anesthesia,Spinal
• Intervention / Treatment: Drug: Bupivacaine; Drug: Morphine; Drug: Lactated Ringer's solution; Drug: Ephedrine, continuous infusion; Drug: Ephedrine, bolus; Drug: Atropine

Detailed 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.

• Study Type: Interventional
• Enrollment (Anticipated): 36
• Phase: Phase 4

Contacts and Locations

Study Locations

• Italy
  • PR
    • Parma, PR, Italy, 43126
      • University and Hospital of Parma (Azienda Ospedaliero-Universitaria di Parma)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Female

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Pharmacological; 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.	Drug: Bupivacaine; 10 mg of a 5 mg/ml hyperbaric solution, intrathecally; Other Names: Local Anesthetic; Marcain; Drug: Morphine; 200 µg of a 100 µg/ml solution, intrathecally; Other Names: Intrathecal morphine; Drug: Lactated Ringer's solution; 25 ml/min intravenously; Drug: Ephedrine, continuous infusion; 37.5 mg/h intravenously; Drug: Ephedrine, bolus; 6.25 mg IV bolus prn. Hypotension defined according to study protocol for each arm.; Drug: Atropine; 0.1 mg/kg iv bolus prn Bradycardia defined as 50% drop in heart rate from baseline values.
Experimental: Non-Pharmacological; 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.	Drug: Bupivacaine; 10 mg of a 5 mg/ml hyperbaric solution, intrathecally; Other Names: Local Anesthetic; Marcain; Drug: Morphine; 200 µg of a 100 µg/ml solution, intrathecally; Other Names: Intrathecal morphine; Drug: Lactated Ringer's solution; 25 ml/min intravenously; Drug: Ephedrine, bolus; 6.25 mg IV bolus prn. Hypotension defined according to study protocol for each arm.; Drug: Atropine; 0.1 mg/kg iv bolus prn Bradycardia defined as 50% drop in heart rate from baseline values.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Neonatal arterial base excess	<5 min from birth

Secondary Outcome Measures

Outcome Measure	Time Frame
Neonatal arterial and venous pH, venous base excess	<5 min from birth
Apgar score	1 and 5 minutes from birth
Maternal serum levels of cardiac troponin (baseline, immediate postsurgery, 6 and 12 hours after surgery)	Baseline and up to 12 h postoperatively
Incidence of maternal hypotension ( <20% baseline or mean arterial pressure <60 mmHg).	q5min from anesthesia to end of surgery
Incidence of maternal bradycardia (heart rate <30% of baseline or <60 beats per minute)	q5min from anesthesia to end of surgery
Peripheral arterial oxygen saturation: incidence of desaturation (SpO2 <92%) and mean values for each arm.	q5min from anesthesia to end of surgery
Administered atropine	from anesthesia to end of surgery
Amount of ephedrine administered (mg)	from anesthesia to end of surgery
Time between induction of anesthesia and skin incision
Time between skin incision and delivery

Collaborators and Investigators

• Sponsor: University of Parma
• Collaborators: Azienda Ospedaliero-Universitaria di Parma
• Investigators: Study Chair: Guido Fanelli, MD, Dept. of Anesthesiology and Critical Care Medicine, University of Parma, Italy; Study Director: Andrea Cornini, MD, UO II Anestesia, Rianimazione e Terapia Antalgica, Azienda Ospedaliero-Universitaria di Parma; Principal Investigator: Michele Zasa, MD, Dept. of Anesthesiology and Critical Care Medicine, University of Parma, Italy

Publications and helpful links

General Publications

• Kinsella SM, Lohmann G. Supine hypotensive syndrome. Obstet Gynecol. 1994 May;83(5 Pt 1):774-88.
• Cyna AM, Andrew M, Emmett RS, Middleton P, Simmons SW. Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database Syst Rev. 2006 Oct 18;(4):CD002251. doi: 10.1002/14651858.CD002251.pub2.
• Kinsella SM, Norris MC. Advance prediction of hypotension at cesarean delivery under spinal anesthesia. Int J Obstet Anesth. 1996 Jan;5(1):3-7. doi: 10.1016/s0959-289x(96)80067-7.
• Helwig JT, Parer JT, Kilpatrick SJ, Laros RK Jr. Umbilical cord blood acid-base state: what is normal? Am J Obstet Gynecol. 1996 Jun;174(6):1807-12; discussion 1812-4. doi: 10.1016/s0002-9378(96)70214-4.

Study record dates

Study Major Dates

• Study Start: September 1, 2009
• Primary Completion (Actual): August 1, 2010
• Study Completion (Actual): August 1, 2010

Study Registration Dates

• First Submitted: October 7, 2009
• First Submitted That Met QC Criteria: October 7, 2009
• First Posted (Estimate): October 8, 2009

Study Record Updates

• Last Update Posted (Estimate): August 27, 2010
• Last Update Submitted That Met QC Criteria: August 26, 2010
• Last Verified: August 1, 2010

More Information

Terms related to this study

• Keywords: Pregnancy; Narcotics; Hypotension; Morphine; Blood pressure; Bupivacaine; Anesthetics, Local; Signs and Symptoms; Anti-Arrhythmia Agents; Bronchodilator Agents; Ephedrine; Atropine; Vasoconstrictor Agents; Adrenergic Agents; Central Nervous System Stimulants; Sympathomimetics; Adjuvants, Anesthesia; Muscarinic Antagonists; Mydriatics; Parasympatholytics; Analgesics, Opioid; Ringer's Lactate; Isotonic Solutions; Anesthesia, Obstetrical; Inferior Vena Cava
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypotension; Physiological Effects of Drugs; Adrenergic Agents; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Anti-Arrhythmia Agents; Central Nervous System Depressants; Parasympatholytics; Autonomic Agents; Peripheral Nervous System Agents; Muscarinic Antagonists; Cholinergic Antagonists; Cholinergic Agents; Analgesics; Sensory System Agents; Analgesics, Opioid; Narcotics; Adjuvants, Anesthesia; Bronchodilator Agents; Anti-Asthmatic Agents; Respiratory System Agents; Central Nervous System Stimulants; Sympathomimetics; Vasoconstrictor Agents; Mydriatics; Nasal Decongestants; Anesthetics; Anesthetics, Local; Bupivacaine; Morphine; Atropine; Ephedrine; Pseudoephedrine
• Other Study ID Numbers: ANEST-OST-02