Does a Single Intravenous Dose of Ketamine Reduce the Need for Supplemental Opioids in Post-Cesarean Section Patients?

Summary

Pain control after cesarean delivery is associated with improved breastfeeding and infant rooming-in times. In addition, inadequate analgesia leads to elevated plasma catecholamine concentrations, which negatively affect every organ system. There is growing evidence that ketamine, N-methyl-D-aspartate receptor antagonist, is efficacious when used as an adjuvant in postoperative pain control. A 2006 Cochrane Collaboration systemic review and meta-analysis concluded, "Ketamine in subanesthetic doses….is effective in reducing morphine requirements in the first 24 hours after surgery."

Ketamine's prolonged analgesic effect, despite its short half-life and its use in low doses, is theorized to be due to blockade of spinal cord central sensitization. Central sensitization is a phenomenon whereby repeated painful stimulus leads to more severe pain perception over time despite no change in the intensity of the painful stimulus.Ketamine may also prevent the development of acute opioid tolerance. Ketamine's analgesic effects have also demonstrated in the obstetric population. Post-cesarean delivery morphine requirements in women who received ketamine as part of a general anesthesia technique were decreased. Similary, low-dose ketamine in conjunction with bupivacaine-only spinal anesthesia reduced postoperative analgesic requirements compared to bupivacaine-only spinal anesthesia and bupivacaine-fentanyl spinal anesthesia.

In the United States, healthy women scheduled for elective cesarean delivery commonly receive spinal anesthesia with bupivacaine-fentanyl-morphine. To our knowledge, IV ketamine has not been studied as an adjuvant to this regimen in the analgesic management in post-cesarean delivery patients. Multimodal therapy for postoperative pain control is widely practiced due to the advantage it provides in blocking multiple pain pathways while minimizing side effects of each individual pain medication. We hypothesize that low dose intravenous ketamine will improve multi-modal post-cesarean analgesia compared to placebo. The purpose of this study is to evaluate this hypothesis and study the possible side effects of this regimen in combination with bupivacaine-fentanyl-morphine spinal anesthesia.

Conditions

• Ketamine Adverse Reaction
• Effects of; Anesthesia, Spinal and Epidural, in Pregnancy
• Complication of Labor and/or Delivery

Interventions

DRUG

Ketamine

Ketamine 10 mg diluted to 20 mL delivered over 10 minutes via an infusion pump set at 2ml/minute

DRUG

Placebo

Saline 20 mL IV infusion delivered over 10 minutes via an infusion pump set at 2ml/minute

Sponsors & Collaborators

• Northwestern University

  lead OTHER

Principal Investigators

• Cynthia A Wong, M.D. · Northwestern University

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

60 Years

Sex

FEMALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2006-07-31

Primary Completion

2008-10-31

Completion

2008-10-31

Countries

• United States

Study Locations