Effect of lidocaine on the minimum alveolar concentration of sevoflurane in dogs.
OBJECTIVE
To investigate the effects of a low-dose constant rate infusion (LCRI; 50 microg kg(-1) minute(-1)) and high-dose CRI (HCRI; 200 microg kg(-1) minute(-1)) lidocaine on arterial blood pressure and on the minimum alveolar concentration (MAC) of sevoflurane (Sevo), in dogs.


METHODS
Prospective, randomized experimental design.


METHODS
Eight healthy adult spayed female dogs, weighing 16.0 +/- 2.1 kg.


METHODS
Each dog was anesthetized with sevoflurane in oxygen and mechanically ventilated, on three separate occasions 7 days apart. Following a 40-minute equilibration period, a 0.1-mL kg(-1) saline loading dose or lidocaine (2 mg kg(-1) intravenously) was administered over 3 minutes, followed by saline CRI or lidocaine LCRI or HCRI. The sevoflurane MAC was determined using a tail clamp. Heart rate (HR), blood pressure and plasma concentration of lidocaine were measured. All values are expressed as mean +/- SD.


RESULTS
The MAC of Sevo was 2.30 +/- 0.19%. The LCRI reduced MAC by 15% to 1.95 +/- 0.23% and HCRI by 37% to 1.45 +/- 0.21%. Diastolic and mean pressure increased with HCRI. Lidocaine plasma concentration was 0.84 +/- 0.18 for LCRI and 1.89 +/- 0.37 microg mL(-1) for HCRI. Seventy-five percent of HCRI dogs vomited during recovery.


CONCLUSIONS
Lidocaine infusions dose dependently decreased the MAC of Sevo, did not induce clinically significant changes in HR or arterial blood pressure, but vomiting was common during recovery in HCRI.
Matsubara
Lídia M
LM
Department of Anesthesiology, Faculdade de Medicina, Botucatu, São Paulo, Brazil. matsubara@fmvz.unesp.br
Oliva
Valéria N L S
VN
Gabas
Daniela T
DT
Oliveira
Guillermo C V
GC
Cassetari
Maria L
ML
D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001794:Blood Pressure; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D007262:Infusions, Intravenous; D008012:Lidocaine / Q000493:pharmacokinetics*; D008738:Methyl Ethers / Q000493:pharmacokinetics*; D011650:Pulmonary Alveoli / Q000378:metabolism*; D000077149:Sevoflurane
D018685:Anesthetics, Inhalation; D000889:Anti-Arrhythmia Agents; D008738:Methyl Ethers; D000077149:Sevoflurane; D008012:Lidocaine