How effective is the local anesthetic infiltration of pin sites prior to application of head clamps: A prospective observational cohort study of hemodynamic response in patients undergoing elective craniotomy

BACKGROUND Use of Mayfield clamps is associated with potentially hazardous hemodynamic effects. Use of local anesthetic infiltration has yielded varying results in blunting of this response. The authors' objective was to study the effect of lidocaine with adrenaline infiltration at Mayfield pin sites on hemodynamic response in comparison with no intervention. METHODS This was a prospective cohort study conducted at a tertiary care center from January 2012 to July 2012. Patents undergoing elective craniotomies over the study period were included and divided in two groups, Group A received lidocaine infiltration of the pin sites prior to insertion, while Group B did not. Hemodynamic response to pin application was then studied at various intervals. RESULTS A total of 30 patients were enrolled in each group. The baseline mean arterial pressure (MAP) and heart rate prior to pin placement in Groups A and B were comparable (P = 0.985 and 0.313). The MAP at 60 seconds after application of skull pins was significantly different in the two groups; 86.13 (±9.73) mmHg versus 104.03 (±12.95) mmHg (P < 0.001). However, the MAP at 30 minutes after application of skull pins in both groups was comparable (P = 0.585). The mean heart rate measured at 60 seconds after skull pin insertion in Group A was 78.23 (±7.19)/min while in Group B, it was 103.07 (±6.98)/min, the difference being statistically significant (P < 0.001). CONCLUSION Hemodynamic changes due to the application of Mayfield clamps during elective craniotomies can be effectively prevented by prior lidocaine with adrenaline infiltration of the pin insertion sites.