Comparison between intravenous dexmedetomidine and local lignocaine infiltration to attenuate the haemodynamic response to skull pin head holder application during craniotomy

Background and Aims: Skull pin application is intensely painful and can be accompanied by detrimental haemodynamic changes. We compared intravenous (IV) dexmedetomidine with local infiltration of lignocaine at pin application sites to attenuate haemodynamic changes associated with pin application. Methods: Fifty-two patients undergoing craniotomy were randomised to either group dexmedetomidine (received 1 μg/kg dexmedetomidine over 10 min starting at induction of anaesthesia) or group lignocaine (received 3 ml of 2% lignocaine infiltration at pin application sites before pin application). Anaesthetic protocol was standardised. Heart rate (HR) and mean arterial pressure (MAP) were recorded at the following time intervals, pre-induction baseline, pre-infiltration, post-infiltration, pre-pin application and post-pin application at 1, 2, 3, 4, 5, 10 and 15 min. Statistical analysis was done using independent samples t-test, Fisher exact test and Chi-square test. Results: HR and MAP were comparable between the groups at all the study intervals. The incidence of adverse haemodynamic effects attributable to pin application (tachycardia and/or hypertension) was comparable between the groups (2 patients in group dexmedetomidine and 5 in group lignocaine). However, the incidence of hypotension and/or bradycardia was significantly greater in the dexmedetomidine group (19 patients in group dexmedetomidine and 5 patients in group lignocaine; P = 0.0007). Conclusion: IV dexmedetomidine 1 mcg/kg over 10 min is comparable to local infiltration of 2% lignocaine at pin application sites to attenuate the haemodynamic response associated with skull pin application. However, use of dexmedetomidine is associated with significantly higher incidence of hypotension and bradycardia.