Gabapentin Premedication Decreases the Hemodynamic Response to Skull Pin Insertion in Patients Undergoing Craniotomy

Abstract

In patients undergoing craniotomy, skull pin insertion produces significant increases in heart rate (HR) and blood pressure. We investigated whether premedication with gabapentin would prevent or attenuate this increase. Forty-seven ASA I and II patients, 18 to 60 years, undergoing elective craniotomy for intracranial tumor surgery were recruited prospectively and randomly divided into 3 groups; L (oral placebo plus 2% lidocaine infiltration at pin sites; n=12), G (oral gabapentin 900 mg plus normal saline infiltration; n=21) and GL (oral gabapentin 900 mg plus 2% lidocaine infiltration; n=14). The oral medications were administered 2 hours before induction of anesthesia. Measurements were made at preinduction baseline, before skull pin insertion and at every 1 minute from pin insertion till end of 10 minutes. Forty-three patients completed the study (L, n=11; G, n=20; GL, n=12). Premedication with gabapentin significantly attenuated the rise in systolic (SBP) and mean arterial pressure (MAP) after pin insertion when compared with placebo (for SBP, P<0.001 at 1 and 2 min and <0.05 at 3 to 5 min between L and G; P<0.001 at 1 to 4 min and <0.05 at 5 min between L and GL; for MAP, P<0.05 at 1 min, <0.001 at 2 min and <0.05 at 3 to 4 min between L and G; P<0.001 at 1 to 2 min and <0.05 at 3 to 5 min between L and GL). HR responses were also attenuated in patients premedicated with gabapentin; however, the responses were more variable in group G (P=0.03 between L and G at 4 min after pin insertion) as compared with group GL (P<0.05 at 1 min, <0.001 at 2 min and <0.05 at 3 to 10 min between L and GL). In conclusion, 900 mg of gabapentin, administered orally 2 hours before induction of anesthesia along with lidocaine scalp infiltration abolished the hemodynamic response after skull pin insertion. Premedication with gabapentin alone significantly attenuated the SBP and MAP; however, HR responses were more variable. A larger trial is required to corroborate the findings of the study before clinical recommendations would be warranted.