title: Comparison of intravenous labetalol and bupivacaine scalp block on the hemodynamic and entropy changes following skull pin application: A randomized, open label clinical trial.
abstract: BACKGROUND
  The application of skull pins in neurosurgical procedures is a highly noxious stimulus that causes hemodynamic changes and a rise in spectral entropy levels. We designed a study to compare intravenous (IV) labetalol and bupivacaine scalp block in blunting these changes.
  
  
  METHODS
  Sixty-six patients undergoing elective neurosurgical procedures were randomized into two groups, L (labetalol) and B (bupivacaine) of 33 each. After a standard induction sequence using fentanyl, propofol and vecuronium, patients were intubated. Baseline hemodynamic parameters and entropy levels were noted. Five minutes before, application of the pins, group L patients received IV labetalol 0.25 mg/kg and group B patients received scalp block with 30 ml of 0.25% bupivacaine. Following application of the pins, heart rate (HR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), and response entropy (RE)/state entropy (SE) were noted at regular time points up to 5 min.
  
  
  RESULTS
  The two groups were comparable with respect to their demographic characteristics. Baseline hemodynamic parameters and entropy levels were also similar. After pinning, the HR, SAP, DAP, MAP, and RE/SE all increased in both groups but were lower in the scalp block group patients. HR increased by 19.8% in group L and by 11% in group B. SAP increased by 11.9% in group L and remained unchanged in group B. DAP increased by 19.7% in group L and by 9.9% in group B, MAP increased by 15.6% in group L and 5% in group B (P < 0.05). No adverse effects were noted.
  
  
  CONCLUSIONS
  Scalp block with bupivacaine is more effective than IV labetalol in attenuating the rise in hemodynamic parameters and entropy changes following skull pin application.
authors.affiliation: Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Sidhesh
authors.initials: S
authors.lastname: Bharne
authors.affiliation: Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Prasanna Udupi
authors.initials: PU
authors.lastname: Bidkar
authors.affiliation: Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Ashok Shankar
authors.initials: AS
authors.lastname: Badhe
authors.affiliation: Department of Anaesthesiology and Critical Care, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Satyen
authors.initials: S
authors.lastname: Parida
authors.affiliation: Department of Neurosurgery, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
authors.forename: Andi Sadayandi
authors.initials: AS
authors.lastname: Ramesh
keywords: Entropy; labetalol; scalp block; skull pins