Relationships between a proprietary index, bispectral index, and hemodynamic variables as a means for evaluating depth of anesthesia in dogs anesthetized with sevoflurane.
OBJECTIVE
To evaluate relationships among various techniques for monitoring anesthetic depth in sevoflurane-anesthetized dogs undergoing orthopedic surgery.


METHODS
10 dogs.


METHODS
Dogs were medicated with acepromazine (0.05 mg/kg, IM), buprenorphine (0.01 mg/kg, IM), and atropine (0.04 mg/kg, IM). Anesthesia was induced and maintained with sevoflurane. Cardiovascular and respiratory responses were monitored. Anesthetic depth was monitored by use of the bispectral index (BIS), and a proprietary index was used to monitor activity of the autonomic nervous system.


RESULTS
A significant decrease in BIS was seen after induction but concurrent changes were not observed for the other techniques. The proprietary index increased significantly after intubation, but no changes were seen for the other techniques. No significant changes were detected during incision or when higher nociceptive stimuli were applied. We did not identify a correlation between BIS and the proprietary index, the proprietary index and hemodynamic variables, or the BIS and hemodynamic variables during induction and maintenance. A significant increase in the proprietary index and BIS was detected at the time of resumption of reflexes. During anesthetic recovery, a correlation was found between the proprietary index and BIS but not between hemodynamic variables and the other techniques.


CONCLUSIONS
A significant increase in the proprietary index, but not the BIS or hemodynamic variables, was detected during intubation. Anesthetic induction with sevoflurane did not prevent the sympathetic stimulus attributable to tracheal intubation. Monitoring of hemodynamic variables does not provide sufficient information to allow clinicians to evaluate stress during anesthetic recovery.
Carrasco-Jiménez
María S
MS
Department of Anesthesiology, Medical School, Hospital Universitario de Puerto Real, Cádiz University, Cadiz, Spain.
Martín Cancho
María F
MF
Lima
Juan R
JR
Crisóstomo
Verónica
V
Usón-Gargallo
Jesús
J
Ezquerra
Luis J
LJ
D000075:Acepromazine; D000769:Anesthesia, Inhalation / Q000662:veterinary*; D000818:Animals; D001285:Atropine; D001794:Blood Pressure / Q000187:drug effects; D002047:Buprenorphine; D002245:Carbon Dioxide / Q000378:metabolism; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000379:methods / Q000662:veterinary; D004569:Electroencephalography / Q000379:methods / Q000662:veterinary; D006339:Heart Rate / Q000187:drug effects; D008738:Methyl Ethers / Q000494:pharmacology*; D010092:Oximetry / Q000662:veterinary; D010100:Oxygen / Q000378:metabolism; D000077149:Sevoflurane; D018709:Statistics, Nonparametric
D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane; D002047:Buprenorphine; D000075:Acepromazine; D001285:Atropine; D010100:Oxygen