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Preoperative clonidine blunts hyperadrenergic and hyperdynamic responses to prolonged tourniquet pressure during general anesthesia
- Publication Year :
- 2002
- Publisher :
- Lippincott Williams & Wilkins, 2002.
-
Abstract
- UNLABELLED Although the mechanism of tourniquet-induced hypertension is still unclear, plasma norepinephrine concentrations continuously increase in parallel to arterial blood pressure during tourniquet inflation. Clonidine attenuates hyperadrenergic and hyperdynamic responses. We investigated the effects of clonidine on prolonged tourniquet inflation. Twenty-nine patients scheduled for elective orthopedic surgery were randomly assigned to receive IV clonidine (3 microg/kg; n = 14) or placebo (n = 15) before tourniquet inflation of the lower limbs under general anesthesia in a double-blinded manner. Arterial blood pressure, heart rate, epinephrine, and norepinephrine plasma concentrations were measured before tourniquet inflation, 60 min after tourniquet inflation, just before tourniquet deflation, and 20 min after tourniquet deflation. Mean arterial blood pressure and norepinephrine plasma-concentrations were significantly lower in the Clonidine group compared with Control after 60 min tourniquet inflation (P = 0.016; P = 0.006). Immediately before deflation of the tourniquet, the difference for mean arterial pressure between groups was even more pronounced (P = 0.005). Twenty minutes after deflation mean arterial blood pressure in the Control group was still increased and significantly higher compared with the Clonidine group (P = 0.002). In conclusion, preoperative IV clonidine blunts hyperadrenergic and hyperdynamic responses resulting from prolonged tourniquet inflation under general anesthesia in ASA class I--II patients. IMPLICATIONS Tourniquet inflation is associated with a continuous increase in arterial blood pressure and sympathetic outflow. This study shows that IV clonidine effectively blunts increases of both arterial blood pressure and plasma norepinephrine concentrations.
- Subjects :
- Adult
Male
Mean arterial pressure
Hemodynamics
610 Medicine & health
Blood Pressure
Anesthesia, General
Clonidine
Norepinephrine (medication)
Norepinephrine
Double-Blind Method
Heart rate
medicine
Humans
Tourniquet
business.industry
10060 Epidemiology, Biostatistics and Prevention Institute (EBPI)
Middle Aged
Tourniquets
equipment and supplies
body regions
surgical procedures, operative
Anesthesiology and Pain Medicine
Epinephrine
Blood pressure
Anesthesia
Multivariate Analysis
Female
2703 Anesthesiology and Pain Medicine
business
medicine.drug
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....7f434e1b9c22cbe66a6c64fd002a439e
- Full Text :
- https://doi.org/10.5167/uzh-113130