Evaluation of the efficacy and safety for use of two sedation and analgesia protocols to facilitate assisted ventilation of healthy dogs.
OBJECTIVE
To determine the effectiveness and safety of 2 sedative-analgesic protocols to facilitate assisted ventilation in healthy dogs.


METHODS
12 healthy dogs.


METHODS
Dogs were randomly assigned to 2 groups. Mean dosages for protocol 1 were diazepam (0.5 mg/kg/h [n = 3 dogs]) or midazolam (0.5 mg/kg/h [3]), morphine (0.6 mg/kg/h [6]), and medetomidine (1.0 microg/kg/h [6]). Mean dosages for protocol 2 were diazepam (0.5 mg/kg/h [n = 3]) or midazolam (0.5 mg/kg/h [3]), fentanyl (18 microg/kg/h [6]), and propofol (2.5 mg/kg/h [6]). Each dog received the drugs for 24 consecutive hours. All dogs were mechanically ventilated with adjustments in minute volume to maintain normocapnia and normoxemia. Cardiorespiratory variables were recorded. A numeric comfort score was assigned hourly to assess efficacy. Mouth care, position change, and physiotherapy were performed every 6 hours. Urine output was measured every 4 hours.


RESULTS
Use of both protocols maintained dogs within optimal comfort ranges > 85% of the time. The first dog in each group was excluded from the study. Significant decreases in heart rate, oxygen consumption, and oxygen extraction ratio were evident for protocol 1. Cardiac index values in ventilated dogs were lower than values reported for healthy unsedated dogs. Oxygen delivery, lactate concentration, and arterial base excess remained within reference ranges for both protocols.


CONCLUSIONS
Use of both protocols was effective for facilitating mechanical ventilation. A reduction in cardiac index was detected for both protocols as a result of bradycardia. However, oxygen delivery and global tissue perfusion were not negatively affected.
Ethier
Michael R
MR
Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON N1H 2W1, Canada.
Mathews
Karol A
KA
Valverde
Alexander
A
Kerr
Carolyn
C
Bersenas
Alexa M
AM
Nykamp
Stephanie G
SG
Davis
Clive
C
D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D004091:Hydromorphone / Q000008:administration & dosage; D006993:Hypnotics and Sedatives / Q000008:administration & dosage / Q000494:pharmacology*; D021061:Liquid Ventilation / Q000379:methods / Q000662:veterinary*; D008297:Male; D020926:Medetomidine / Q000008:administration & dosage / Q000494:pharmacology; D008874:Midazolam / Q000008:administration & dosage / Q000494:pharmacology; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology; D012016:Reference Values; D012449:Safety; D013318:Stroke Volume / Q000187:drug effects; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000187:drug effects
D000700:Analgesics; D000701:Analgesics, Opioid; D006993:Hypnotics and Sedatives; D009020:Morphine; D020926:Medetomidine; D004091:Hydromorphone; D008874:Midazolam