Keihan Golshani, MD, FIFEM
Faculty Member and Consultant Physician
Representative of ISEM at IFEM
Alzahra University Hospital
Kashani General Hospital
Isfahan University of Medical Sciences, Isfahan, Iran
Topical Ketamine as a Local Anesthetic Agent in Reducing Venipuncture Pain: a Randomized Controlled Trial
Farhad Heydari1 Sanaz Khalilian1, Saeed Majidinejad1, Babak Masoumi1, Keihan Golshani2
Background and Objectives
Optimal pain management is an important issue in all Emergency Departments (EDs) and according to the local resources and personnel experts, there are vast variety of protocols to reduce pain. EMLA containing 2.5% lidocaine and 2.5% perlocaine is a common topical cream that widely use as a local anesthetic agent. Many studies supported the safety and efficacy of EMLA in relieving pain from minor procedures such as venipuncture or dermatological ones such as micro abrasion. As to best of our knowledge, there is not any clinical trial yet to evaluate the local cutaneous effects of ketamine to relief pain in EDs. Therefore, this study designed to evaluate the local cutaneous effects of ketamine on acute pain reduction and to compare its topical anesthetic effects with EMLA.
A prospective randomized double-blind clinical trial was conducted in two university teaching hospital.
Inclusion criteria was adults more than 18 years old, classified as level 4 or 5 by ESI triage system, without any previous distracting pain or confusional state. After obtaining a written consent from them, they enrolled to the study. 300 adult patients randomly assigned to three groups (EMLA, local Ketamine, placebo) using a block randomization with a block of three.
In group one, the site of venipuncture was covered with 2 gram of topical ketamine cream 10% (a mixed of 100mg ketamine with 10 g of cold cream). In group 2, The site of venipuncture was covered with 2 grams of 5% EMLA cream on a 5*5 cm2 surface area over the site of cannulation in a thick layer. And finally, in group 3, The site of venipuncture was covered with placebo (2 g of cold cream).
An occlusive dressing applied for all groups. The cream placed 60 minutes before the procedure over the phlebotomy site (antecubital fossa).
When complete numbness achieved (first by asking the patients and after they confirmed local numbness, we have been rechecked it with a sharp pin and compared it with the other antecubital fossa of the patient), then the onset of complete numbness was recorded and the cream was removed and the area was disinfected. Professional nurses who were blind to the study, assigned to perform phlebotomies by using 20 G needles. Visual analogue scale was used to assess the pain associated with the venipuncture. Immediately after the venipuncture, all patients were asked to rate the pain associated with the venipuncture based on VAS. During the study, local side effects, systemic effects and onset of numbness were recorded at the same time by blinded emergency medicine residents. Recorded data was analyzed using SPSS version 22 software.
Results showed that the mean onset of complete local numbness was not significantly different between 1st and 2nd group (ketamine and EMLA groups) [58.2 +/- 9.48 minutes VS 57.82 +/- 10.18] ( (P=0.419).
The pain associated with the venipuncture in 1st and 2nd group were significantly lower as compared to placebo group (1.72 ±0.44 and 1.66 ±0.51 vs. 3.16 ±1.2, P< 0.001).
There was not any difference in vital signs between the groups 1 and 2 before and after the procedure, suggesting a lack of significant systemic absorption of Ketamine.
We just studied low acuity adult population with a non emergent medical indication for venipuncture. The severity of pain due to venipuncture was just evaluated by VAS that is a subjective method.
The patients in placebo group hadn’t any local numbness that can be a confounder, in our study.
The skin thickness affects topical drug absorption. So, further studies should evaluate it more precisely.
This study showed that local cutaneous ketamine is as effective as EMLA in relieving pain during venipuncture.
For the future:
We suggest to perform further studies to confirm usefulness of topical cutaneous ketamine for more practical minor procedures in the EDs.
1Emergency Department, Alzahra University Hospital, Isfahan University of Medical Sciences, MD, Iran
2Emergency Department, Alzahra University Hospital, Isfahan University of Medical Sciences, MD, FIFEM, Iran