Oral clonidine attenuates the fall in mean arterial pressure due to scalp infiltration with epinephrine-lidocaine solution in patients undergoing craniotomy: a prospective, randomized, double-blind, and placebo controlled trial.
BACKGROUND
Scalp infiltration with epinephrine-lidocaine solution in patients undergoing neurosurgery may result in transient but significant hypotension. We investigated whether premedication with alpha2-adrenoreceptor agonist clonidine, which also exhibits alpha1-adrenoreceptor mediated vasoconstriction, would prevent or attenuate this fall in mean arterial pressure (MAP).


METHODS
Sixty-six American Society of Anesthesiologists I and II adult patients, 18 to 50 years, undergoing elective tumor decompression were recruited into this prospective, randomized, double-blind, placebo controlled study, and scheduled to receive either oral pantoprazole 40 mg (placebo group) or oral clonidine 3 microg/kg (clonidine group), 90 minutes before induction of anesthesia. Primary end points studied were heart rate (HR) and MAP in both groups measured just before scalp infiltration (preinfiltration baseline) and then every 30 seconds for 5 minutes after initiation of scalp infiltration with 2.5 microg/mL epinephrine contained in 15 mL of 1% lidocaine solution.


RESULTS
There was no significant change in HR in the 2 groups during the study period compared with baseline values; however, patients in clonidine group had significantly lower HR compared with placebo (*P<0.05). In both groups, MAP fell significantly below baseline 1 minute after start of infiltration. It recovered in the clonidine group after 2.5 minutes but not in the placebo group where it continued to remain low even at 5 minutes. MAP in the placebo group was also significantly lower compared with the clonidine group from 2.5 minutes to 5 minutes.


CONCLUSIONS
In conclusion, oral clonidine 3 microg/kg administered 90 minutes before induction of anesthesia attenuates the fall in MAP due to scalp infiltration with a dilute concentration of epinephrine-lidocaine solution in patients undergoing craniotomy under isoflurane anesthesia.
Misra
Satyajeet
S
Department of Anesthesiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology Trivandrum, Kerala-695011, India. misrasatyajeet@gmail.com
Koshy
Thomas
T
Suneel
Puthuvassery Raman
PR
D000293:Adolescent; D000328:Adult; D000768:Anesthesia, General; D000772:Anesthesia, Local; D000779:Anesthetics, Local / Q000493:pharmacokinetics; D000959:Antihypertensive Agents; D001794:Blood Pressure / Q000187:drug effects*; D003000:Clonidine; D003399:Craniotomy; D004311:Double-Blind Method; D004837:Epinephrine / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D011229:Preanesthetic Medication; D011446:Prospective Studies; D014662:Vasoconstrictor Agents / Q000493:pharmacokinetics; D055815:Young Adult
D000779:Anesthetics, Local; D000959:Antihypertensive Agents; D014662:Vasoconstrictor Agents; D008012:Lidocaine; D003000:Clonidine; D004837:Epinephrine