Prevention of propofol injection pain, using lidocaine in a large volume does it make a difference? A prospective randomized controlled double blinded study

Purpose
Propofol has become one of the most common anesthetic agents used for anesthesia because of its unique pharmacologic properties. Pain during bolus injection is a major drawback of propofol. The target of this study was to study the effect of lidocaine used in a large volume on prevention of propofol injection pain. Our hypothesis is that IV administration of diluted lidocaine in a large volume before propofol injection could be more effective in prevention of both immediate and delayed types of pain associated with propofol injection than the most commonly used method of mixing lidocaine with propofol (30 mg lidocaine/added to the 20 ml propofol syringe).
Methods
100 Patients with age range (20–60) years and classified ASA1 and ASA2 undergoing general anesthesia for elective surgery were included in this study. Patients were classified into two groups, the first (study) group, in which 30 mg lidocaine diluted into a total volume of 20 ml using normal saline was given IV after venous occlusion with rubber tourniquet followed by propofol injection. In the second (control) group, 30 mg lidocaine was mixed with propofol and given to the patient as commonly used.
Results
This study showed a highly significant reduction in the propofol injection pain in the study group compared to the control group.
Conclusion
lidocaine when given diluted in a large volume after venous occlusion has dramatically reduced propofol injection pain in adults.