[Premedication with clonidine in the neurosurgical patient: sedation, anesthetic requirements and hemodynamic perfusion].
OBJECTIVE
To analyze the effect of premedication with clonidine on postoperative sedation, anesthetic requirements and hemodynamic repercussions in patients undergoing craniotomy due to supratentorial intracranial pathology.


METHODS
Twenty ASA I/II patients in a double-blind prospective study were assigned randomly to receive lorazepam (0.03 mg/kg/po, n = 10) or clonidine (0.005 mg/kg/po, n = 10) the night before and 90 minutes before surgery. Arterial pressure and heart rate were monitored continuously during and immediately after surgery (first 24 hours). Anesthetic induction was achieved with thiopental (maximum 6 mg/kg) and maintained with O2/N2O and an infusion of alfentanyl (1 microgram/kg/min). Hemodynamic response to surgical stimulus was treated with additional boluses of alfentanyl up to a maximum dose of 0.1 mg/kg and with an increase in infusion dosage to 2 micrograms/kg/min. When these were ineffective, isoflurane was given. All patients were extubated in the operating room.


RESULTS
No differences in level of sedation were found between the two groups. The infusion dose and total amount of alfentanyl given were smaller for patients treated with clonidine (0.8 +/- 0.04 vs 0.6 +/- 0.01 microgram/kg/min and 22.4 +/- 5.3 vs 17.5 +/- 4.9 mg, respectively) (p < 0.05). No differences were found in isoflurane requirements (5/5 vs 2/8). Mean arterial pressure and heart rate were lower with clonidine from 3 minutes after intubation until the patient's arrival in the recovery room (p < 0.05), with marked bradycardia (49 +/- 5 vs 73 +/- 7 bpm) (p < 0.05) upon intubation.


CONCLUSIONS
Premedication of neurosurgical patients with clonidine offers no advantages over lorazepam with respect to sedation. Nevertheless, clonidine may offer advantages with respect to the amount of alfentanyl required and attenuation of perioperative adrenergic response.
García-Guiral
M
M
Servicio de Anestesiología y Reanimación, Hospital Puerta de Hierro, Madrid.
Carrera
A
A
Lora-Tamayo
J I
JI
Luengo
C
C
Pascual
E
E
Quintana
B
B
Horno
R
R
D000328:Adult; D000768:Anesthesia, General; D003000:Clonidine / Q000008:administration & dosage / Q000627:therapeutic use*; D003399:Craniotomy; D004311:Double-Blind Method; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000627:therapeutic use*; D008140:Lorazepam / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011229:Preanesthetic Medication; D011446:Prospective Studies; D015173:Supratentorial Neoplasms / Q000601:surgery; D013564:Sympathetic Nervous System / Q000187:drug effects
D006993:Hypnotics and Sedatives; D003000:Clonidine; D008140:Lorazepam
Premedicación con clonidina en el paciente neuroquirúrgico: sedación, requerimientos anestésicos y repercusión hemodinámica.