EVALUATION OF ORAL KETAMINE FOR PAIN RELIEF IN WOUND CARE PROCEDURES IN THE ADULT BURNS PATIENTS

Abstract

Procedural burns pain has been described by many adult burns patients as the worst they have ever experienced. Ketamine, an NMDA antagonist, is known to have a very potent analgesic property at subanaesthetic doses. This prospective single-blind randomized study evaluated the usefulness of oral ketamine as an analgesic for wound care procedures in fifty-one (51) adult patients undergoing burns wound dressing. The study was conducted at the National Orthopaedic Hospital, Enugu over a one year period between June 2006 and May 2007. Two hundred and forty (240) wound care procedures were randomly assigned to 6 treatment groups. Group A received 0.5mgkg-1 of ketamine; group B 2mgkg-1; group C 4mgkg-1; group D 6mgkg1; group E 8mgkg-1 and group F 10mgkg-1. A 5-point verbal rating scale assessed pain intensity while AVPU scale was used for level of consciousness. A 6-point Likert scale was used for patient’s satisfaction assessment. Non-invasive blood pressure, pulse rate and arterial oxygen saturation were monitored. Occurrence of adverse/side effects was reported. Comparison of efficacy and safety of the different dosages of oral ketamine were made using the SPSS package. Efficacy criterion was a VRS ≤ 2 i.e. no pain, mild pain or discomfort. Patients in groups A and B reported higher levels of pain while group C, D, E and F had varying degrees of efficacy. Groups E and F provided the best analgesic profile but the higher doses used resulted in the patients becoming anaesthetized. Burns dressings lasting less than 20 mins were associated with lower levels of pains than those beyond 20 mins. The commonest adverse / side effects reported were hallucination (37.0%) and hypersalivation (29.9%). These occurred more frequently in groups E and F. Group D had the best and group A the worst patients’ assessment of pain management profile. This study has shown that the minimum effective subanaesthetic dose of oral ketamine is 6mgkg-1 for providing analgesia in procedural burns pain. Increasing the dose further increases the analgesic effect with the risk of anaesthetizing the patients and increasing the adverse / side effects.