A COMPARISON OF ALFENTANIL, ESMOLOL, LIDOCAINE, AND THIOPENTAL SODIUMON THE HEMODYNAMIC-RESPONSE TO INSERTION OF HEADREST SKULL PINS

Study Objectives: To compare the effects of four techniques for preven ting or blunting the hypertensive response to the insertion of Mayfiel d 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 p atients 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 minu tes 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. Measu rements and Main Results: Blood pressure and heart rate (HR) were reco rded immediately prior to and after pin insertion with balanced genera l anesthesia, and at 30, 60, 120, and 180-second intervals after pin i nsertion. The measurements were compared with the immediate preinserti on values. In the ALF and XYL groups, there was no significant increas e in mean arterial pressure (MAP) or HR for any of the measurement per iods. MAP was elevated immediately on pin insertion and for up to 2 mi nutes 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 th e hemodynamic response to the insertion of skull pins in anesthetized patients. Neither ESM nor TPL prevented the hypertensive response. Loc al anesthetic injection into the scalp requires coordination between t he anesthesiologist and surgeon, it carries the risk of needle stick i njury, 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 alternati ve to the use of XYL injection.