The effect of bupivacaine skull block on the hemodynamic response to craniotomy.
The placement of pointed cranial pins into the periosteum is a recognized acute noxious stimulation during intracranial surgery which can result in sudden increases in blood pressure and heart rate, causing increases 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 auriculotemporal nerves, and the greater auricular nerves) may be effective in reducing hypertension and tachycardia. Twenty-one patients were allocated in a prospective, double-blind fashion to a control group or a bupivacaine group. After a standardized induction and 5 min prior to head pinning, a skull block was performed. Patients in the control group received a skull block of normal saline, while the bupivacaine group received a skull block with 0.5% bupivacaine. Systolic (SAP), diastolic (DAP), mean arterial pressure (MAP), heart rate (HR), and end-tidal isoflurane were recorded at the following times: 5 min after the induction of anesthesia, during performance of the skull block, during head pinning, 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 remaining unchanged in the bupivacaine group. These results demonstrate that a skull block using 0.5% bupivacaine successfully blunts the hemodynamic response to head pinning.