INTRODUCTION: Propofol, a commonly used intravenous anesthetic induction agent, frequently produces pain on injection, with an incidence ranging from 28% to 91%. This study aimed to compare the effect of low-dose ketamine and a pressure vibration mechanical device with placebo in reducing pain during propofol injection in patients undergoing elective surgery.
METHODS: In this randomized, double-blind, placebo-controlled trial, 300 adults were allocated to pressure vibration (Group V), low-dose ketamine (Group K), or saline placebo (Group P); 275 patients completed the study and were analyzed (92, 91, and 92 patients, respectively). Group P received 5 mL 0.9% saline, Group K ketamine 50 µg/kg diluted in 5 mL saline, and Group V saline with an activated pressure vibration device applied proximal to the intravenous cannula, each administered over 1 min. Propofol 2 mg/kg was infused, with the first 25% delivered at 600 mL/hour, and pain assessed using the McCrirrick and Hunter verbal rating score. The primary outcome was pain on propofol injection. Continuous variables were analyzed using one-way analysis of variance or Kruskal-Wallis tests, categorical variables with ?² tests, with Bonferroni correction applied for multiple primary outcome comparisons.
RESULTS: Among 275 analyzed patients, the incidence of no pain was highest in the pressure vibration device group 51.1%; 95% CI 42.4% to 59.8% compared with placebo 30.4%; 95% CI 21.0% to 39.8% and ketamine 33.0%; 95% CI 23.3% to 42.6%; (p=0.001). Severe pain was more frequent in the placebo group (18.5%; 95% CI 10.5% to 26.4%) than in the ketamine (5.5%; 95% CI 0.8% to 10.2%) and vibration groups (4.3%; 95% CI 0.2% to 8.5%; (p=0.001). Recall of injection pain at 1 week was significantly higher with placebo compared with ketamine and vibration device (55.4%, 37.4%, and 26.1%, respectively; p<0.001). Hemodynamic variables and adverse events were comparable across groups.
CONCLUSION: The pressure vibration mechanical device significantly reduced the incidence and severity of propofol injection pain compared with placebo and was at least as effective as low-dose ketamine. Pain recall at 1 week was higher with placebo. This device provides an effective, reusable, non-pharmacological alternative without drug-related adverse effects.
TRIAL REGISTRATION NUMBER: CTRI/2022/12/048300.
| Discipline Area | Score |
|---|---|
| Physician |  |
Physician rater
The authors studied other methods to reduce pain during propofol injection. Mechanical vibration is surprisingly effective.
Physician rater
The authors investigated a vibratory device placed proximal to the intravenous catheter for treating pain from a propofol injection. The device functioned as well as intravenous ketamine. The authors also established that placebo (5 cc NS) produced no pain with a propofol injection. It would be interesting to study why some patients experience severe pain with propofol while others no pain. Also, it is unclear why the authors did not include an intravenous lidocaine group.
, McMaster University