Prevention of Shivering during Regional Anesthesia in Cesarean Section: Comparison of the Two Different Doses of Ketamine and Placebo

Postanesthetic shivering is one of the important complications of regional anesthesia that causes discomfort for patient and increases the metabolic rate up to 400%. We compared the efficacy of two low doses of ketamine on prevention of postanesthetic shivering in Cesarean section under spinal anesthesia.
In this randomized double-blind placebo-controlled clinical trial, 135 patients with classes I-II of American Society of Anesthesiologists (ASA) grading undergoing elective Cesarean section under spinal anesthesia were involved. Patients were randomly allocated to three group: K1:0.3 mg/kg ketamine up to 4 cc normal saline, K2: 0.5mg/kg ketamine up to 4 cc normal saline, and C: 4 cc normal saline. Drugs were injected after cord clamping and vital signs and outbreak and grade of shivering were detected immediately after the anesthesia and every 15 minutes until leaving the recovery room.
Findings: Rate of the postanesthetic shivering in groups that receive medication (K1 and K2) was significantly less than control group at 45 (K1: 11.1%, K2: 0.0%, and C: 17.8%) and 60 (K1: 15.6%, K2: 8.9%, and C: 51.1%) minutes after initiation of the surgery and the 15th minutes in recovery (K1: 42.2%, K2: 24.4%, C: 68.9%) (P = 0.015, P Using ketamine with the dosage of 0.5 mg/kg is more effective than 0.3 mg/kg in prevention of postanesthetic shivering in Cesarean section under spinal anesthesia.