THE EFFECT OF BUPIVACAINE SKULL BLOCK ON THE HEMODYNAMIC-RESPONSE TO CRANIOTOMY

The placement of pointed cranial pins into the periosteum is a recogni zed acute noxious stimulation during intracranial surgery which can re sult in sudden increases in blood pressure and heart rate, causing inc reases in intracranial pressure. A skull block (blockade of the nerves that innervate the scalp, including the greater and lesser occipital nerves, the supraorbital and supratrochlear nerves, the auriculotempor al nerves, and the greater auricular nerves) may be effective in reduc ing hypertension and tachycardia. Twenty-one patients were allocated i n a prospective, double-blind fashion to a control group or a bupivaca ine group. After a standardized induction and 5 min prior to head pinn ing, a skull block was performed. Patients in the control group receiv ed a skull block of normal saline, while the bupivacaine group receive d a skull block with 0.5% bupivacaine. Systolic (SAP), diastolic (DAP) , mean arterial pressure (MAP), heart rate (HR), and end-tidal isoflur ane were recorded at the following times: 5 min after the induction of anesthesia, during performance of the skull block, during head pinnin g, and 5 min after head pinning. Significant increases in SAP of 40 +/ - 6 mm Hg, DAP of 30 +/- 5 mm Hg, MAP of 32 +/- 6 mm Hg, and HR of 22 +/- 5 bpm occurred during head pinning in the control group, while rem aining unchanged in the bupivacaine group. These results demonstrate t hat a skull block using 0.5% bupivacaine successfully blunts the hemod ynamic response to head pinning.