Does lidocaine more effectively prevent pain upon induction with propofol or etomidate when given preemptively than when mixed with the drug?

STUDY

OBJECTIVE

To compare the efficacy of 2% lidocaine "timing" on alleviation of pain upon induction using propofol or etomidate.

DESIGN

Prospective, randomized, double-blinded study.

SETTING

Academic teaching hospital.

PATIENTS: 80 adult, ASA physical status I, II, and III patients scheduled for elective outpatient or inpatient surgery with an intravenous induction agent.

INTERVENTIONS: Patients were randomly assigned to two groups. Group A received preemptive saline 4 mL and lidocaine 4 mL mixed with either propofol 20 mL (n = 20) or etomidate 20 mL (n = 20). Group B received preemptive lidocaine 4 mL and saline 4 mL mixed with either propofol 20 mL (n = 20) or etomidate 20 mL (n = 20). The 4 mL dose of preemptive drug dwelled for three minutes.

MEASUREMENTS: The induction drug mixture was injected over 60 seconds while the patient was assessed for pain using a 4-point scale (0 = no pain,1 = mild, 2 = moderate, and 3 = severe).

MAIN

RESULTS

Mean induction pain scores were 1.0 (SD = 0.89) for propofol and 0.9 (SD = 0.90) for etomidate, representing mild induction pain. Mean induction pain scores were 0.93 (SD = 0.92) for the simultaneous treatment groups and 0.98 (SD = 0.87) for the preemptive treatment groups. The observed differences in pain scores between the techniques were not statistically (P > 0.62) or clinically meaningful.

CONCLUSIONS

Alleviation and intensity of post-injection pain were not significantly influenced by the "timing" of administration of lidocaine 80 mg or by the specific induction drug. Pre-lidocaine and "simultaneous" lidocaine with either propofol or etomidate prevented severe pain in 95% of patients.