Propofol injection pain: Is it still an issue? The effect of premedication

Background. The use of propofol often results in pain upon injection. Various strategies can be used to reduce this pain, ranging from the administration of analgesics to modification of the propofol emulsion. However, basic premedication protocol aimed at peri- and postoperative pain reduction could also sufficiently reduce propofol injection pain, rendering other special interventions redundant.
Methods. With the approval of the Local Ethics Committee of the Erasmus Medical Centre Rotterdam, and after obtaining written informed consent from each patient included, 209 surgical patients (ASA physical status I-III) were randomized in a double-blind manner to receive premedication consisting of 7.5 mg midazolam, 50 mg diclofenac and 1 000 mg acetaminophen (all orally administered) and fentanyl (intravenously administered) or placebo medication the hour before surgery. In both groups a mixture of 40 mL propofol 1% with 2 mL lidocaine 1% was used to induce anesthesia. Pain scores were assessed using a verbal analog scale (VAS) ranging from 0-10.
Results. The premedication group was found to have significantly less pain upon injection of propofol (median VAS 0±0-2) (median±interquartile range) when compared to the control group (median VAS 1.5±0-4; P=0.001). In addition, more patients in the premedication group experienced no pain at all. This effect was still present one hour after extubation.
Conclusion. Even when injection pain is reduced, the use of a premedication regimen clearly has additional value with respect to the patients' experience. Considering the low VAS scores observed overall, it might be worthwhile to reserve additional injection pain-reducing interventions for individual patients rather than adding them as a component of standard practice.