A comparison of alfentanil, esmolol, lidocaine, and thiopental sodium on the hemodynamic response to insertion of headrest skull pins.

STUDY OBJECTIVES

To compare the effects of four techniques for preventing or blunting the hypertensive response to the insertion of Mayfield headrest skull pins: intravenous (IV) alfentanil (ALF), esmolol (ESM), thiopental sodium (TPL), and local anesthesia using plain lidocaine (Xylocaine; XYL).

DESIGN

Randomized open study.

PATIENTS

40 adult patients undergoing intracranial or spinal surgery requiring the use of Mayfield headrest skull pins for head positioning and immobilization.

INTERVENTIONS

20 minutes after anesthetic induction, and 2 to 3 minutes prior to the insertion of headrest skull pins, one of three drugs was administered IV: ALF 10 mcg/kg, ESM 1 mg/kg, or TPL 1.5 mg/kg. The fourth drug, XYL, was administered by injection into the scalp.

MEASUREMENTS AND MAIN RESULTS

Blood pressure and heart rate (HR) were recorded immediately prior to and after pin insertion with balanced general anesthesia, and at 30, 60, 120, and 180-second intervals after pin insertion. The measurements were compared with the immediate preinsertion values. In the ALF and XYL groups, there was no significant increase in mean arterial pressure (MAP) or HR for any of the measurement periods. MAP was elevated immediately on pin insertion and for up to 2 minutes in the TPL group, and for up to 3 minutes in the ESM group (p < 0.05). HR changes were seen in the TPL group for up to one minute (p < 0.05). Increases in systolic blood pressure were seen in the TPL and ESM groups for up to 3 minutes, and in diastolic blood pressure for up to 2 minutes (p < 0.05). No other significant changes were observed.

CONCLUSIONS

IV ALF and local injection of XYL in the scalp prevent the hemodynamic response to the insertion of skull pins in anesthetized patients. Neither ESM nor TPL prevented the hypertensive response. Local anesthetic injection into the scalp requires coordination between the anesthesiologist and surgeon, it carries the risk of needle stick injury, and it must be repeated if the surgeon repositions the headrest. The rapid onset and short half-life of ALF, coupled with the absence of hemodynamic effects at the dose used, makes this drug an alternative to the use of XYL injection.