Evaluation of low-dose propofol preadministration to attenuate vascular pain during induction of anesthesia

STUDY OBJECTIVE: To determine whether a small dose of propofol before induction decreases pain with injection using two different formulas of propofol-10% long-chain triglycerides (LCT) and medium-chain triglycerides (MCT) and LCT. DESIGN: Prospective, randomized, comparative study. SETTING: University-affiliated hospital. PATIENTS: 200 ASA physical status I and II patients. INTERVENTIONS: Group A (LCT control) and group B (MCT/LCT control) were first preadministered normal saline plus Intralipid (Otsuka Pharmaceutical Co, Ltd, Tokyo, Japan) as a placebo, whereas group C (LCT study) and group D (MCT/LCT study) received each formulation of propofol 0.1 mg/kg before induction. After three minutes, groups A and C received LCT propofol two mg/kg for induction. Groups B and D received LCT/MCT propofol in the same manner. MEASUREMENT: Pain was evaluated blindly at the time of both preadministration and induction, using a 4-point scale: 0 = no pain, 1 = mild pain, 2 = moderate pain, and 3 = severe pain. MAIN RESULTS: 36 (72%) LCT and 31 (62%) LCT/MCT control group patients (groups A and B) had pain. Pretreatment with propofol (groups C and D) attenuated the frequency of pain significantly in 21 (42%) and 24 (48%) patients at induction, respectively. CONCLUSION: Long-chain triglyceride and LCT/MCT propofol, 0.1 mg/kg administration before induction, resulted in attenuated pain at an induction dose of propofol.