Cardiorespiratory effects of epidural administration of morphine and fentanyl in dogs anesthetized with sevoflurane.
OBJECTIVE
To determine the cardiorespiratory effects of epidural administration of morphine alone and in combination with fentanyl in dogs anesthetized with sevoflurane.


METHODS
Prospective study.


METHODS
6 dogs.


METHODS
Dogs were anesthetized with sevoflurane and allowed to breathe spontaneously. After a stable plane of anesthesia was achieved, morphine (0.1 mg/kg [0.045 mg/lb]) or a combination of morphine and fentanyl (10 microg/kg [4.5 microg/lb]) was administered through an epidural catheter, the tip of which was positioned at the level of L6 or L7. Cardiorespiratory variables were measured for 90 minutes.


RESULTS
Epidural administration of morphine alone did not cause any significant changes in cardiorespiratory measurements. However, epidural administration of morphine and fentanyl induced significant decreases in diastolic and mean arterial blood pressures and total peripheral resistance. Stroke volume was unchanged, PaCO2 was significantly increased, and arterial pH and base excess were significantly decreased. Heart rate was significantly lower after epidural administration of morphine and fentanyl than after administration of morphine alone. None of the dogs had any evidence of urine retention, vomiting, or pruritus after recovery from anesthesia.


CONCLUSIONS
Results suggest that epidural administration of morphine at a dose of 0.1 mg/kg in combination with fentanyl at a dose of 10 microg/kg can cause cardiorespiratory depression in dogs anesthetized with sevoflurane.
Naganobu
Kiyokazu
K
Veterinary Teaching Hospital, Faculty of Agriculture, Miyazaki University, Miyazaki 889-2192, Japan.
Maeda
Noriaki
N
Miyamoto
Toru
T
Hagio
Mitsuyoshi
M
Nakamura
Tadashi
T
Takasaki
Mayumi
M
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D018685:Anesthetics, Inhalation; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D005283:Fentanyl / Q000008:administration & dosage / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects*; D007268:Injections, Epidural / Q000379:methods / Q000662:veterinary; D008297:Male; D008738:Methyl Ethers; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D011446:Prospective Studies; D012119:Respiration / Q000187:drug effects*; D000077149:Sevoflurane
D000701:Analgesics, Opioid; D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D000077149:Sevoflurane; D009020:Morphine; D005283:Fentanyl