Injection pain with propofol. Reduction with aspiration of blood

A randomised, controlled, single-blind study was performed on 100 patients to investigate a new method of reducing pain on propofol injection. Aspiration of 2 ml of the patient's blood into a syringe of propofol immediately before injection was compared with the addition of lignocaine 20 mg or normal saline 2 ml to the propofol before injection. The addition of blood was significantly more effective in reducing pain on injection than the addition of saline (p < 0.001), but was not significantly more effective than the addition of lignocaine.