Preoperative Ketamine Has no Preemptive Analgesic Effect in Patients Undergoing Colon Surgery.
Status:
Completed
Trial end date:
2002-06-01
Target enrollment:
Participant gender:
Summary
The analgesic properties of ketamine are associated with its non-competitive antagonism of
the N-methyl-D-aspartate receptor; these receptors exhibit an excitatory function on pain
transmission and this binding seems to inhibit or reverse the central sensitization of pain.
In the literature, the value of this anesthetic for preemptive analgesia in the control of
postoperative pain is uncertain. The objective of this study was to ascertain whether
preoperative low-dose ketamine reduces postoperative pain and morphine consumption in adults
undergoing colon surgery.
In a double-blind, randomized trial, 48 patients were studied. Patients in the ketamine group
received 0.5 mg/kg intravenous ketamine before surgical incision, while the control group
received normal saline. The postoperative analgesia was achieved with a continuous infusion
of morphine at 0.015 mg∙kgˉ¹∙hˉ¹ with the possibility of 0.02 mg/kg bolus every 10 min. Pain
was assessed using the Visual Analog Scale (VAS), morphine consumption, and hemodynamic
parameters at 0, 1, 2, 4, 8, 12, 16, and 24 hours postoperatively. We quantified times to
rescue analgesic (Paracetamol), adverse effects and patient satisfaction.