Attenuation of Hemodynamic Response to Skull Pin Head Holder Insertion: Intravenous Clonidine versus Intravenous Lignocaine Infusion.

BACKGROUND: Insertion of skull pin induces a significant increase in heart rate (HR), blood pressure (BP) and intracranial pressure. Alpha 2 agonist clonidine and intravenous (i.v.) lignocaine are effective in attenuating stress response. Local infiltration of pin site and scalp block with lignocaine are commonly used techniques for prevention of hemodynamic response to skull pin insertion. We compared the effectiveness of i.v. clonidine infusion and i.v. lignocaine infusion in suppressing the hemodynamic response to skull pin head holder insertion.

DESIGNS: Randomized double blind study conducted with sample size - sixty patients, divided into two groups: Group C (n = 30) - clonidine i.v. dose 2 μg/kg; Group L (n = 30) - lignocaine i.v. dose 1.5 mg/kg.

MATERIALS AND METHODS: All patients posted for elective craniotomy belonging to American Society of Anesthesiologists (ASA) 1 and 2, age group 18-70 were included in the study. ASA 3, 4; difficult airway; hypertensives; allergy to study drugs; ischemic heart disease; and arteriovenous malformations were excluded. Study drugs were administered 10 min prior to induction in 10 ml syringes with infusion pump over 10 min. Standard anesthesia protocol followed. HR, noninvasive BP, mean arterial pressure (MAP), and IBP were recorded at baseline (BL), after study drug (AD), 1 min after intubation (AI), 1 min prior to pin insertion -pre pin (PP), and 5 min after pin insertion (AP).

ANALYSIS: Descriptive and inferential statistical analysis - Student's t- and Chi-square/Fisher exact test were used (SAS 9.2, SPSS 15.0) P value described as *moderately significant (P value: 0.01 < P ≤ 0.05) **strongly significant (P value: P ≤ 0.01).

RESULTS: Groups were matched with respect to age (P = 0.7), gender distribution (P = 0.6), and weight (P = 0.67) There was no difference in BL HR in two groups. Significant difference in HR was noted after intubation P < 0.031 and pin insertion P < 0.001 stages with lower HR in Group C (76.03 ± 9.88) versus Group L (98 ± 60.89) MAP recordings showed no statistically significant difference in two groups at BL and after drug administration stages. A significant difference was seen in intubation (P < 0.014), very significant difference (P < 0.001) was noted in pre- and post-pin insertion stages with MAP was lower in Group C (76.03 ± 9.88) versus Group L (87.17 ± 8.90).

CONCLUSION: i.v. clonidine at dose of 2 μg/kg is a better drug in attenuating hemodynamic response to skull pin head holder insertion than i.v. lignocaine.