Induction of general anaesthesia by rapid injection of propofol and dexmedetomidine or propofol and buthorphanol: cardiopulmonary and echocardiographic parameters in unpremedicated dogs

2011 The Authors. Veterinary Anaesthesia and Analgesia
20 2011 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists, 38, 1–35 Induction of general anaesthesia by rapid
injection of propofol and dexmedetomidine
or propofol and butorphanol:
cardiopulmonary and echocardiographic
parameters in unpremedicated dogs
G Ravasio, L Borghi, D Fonda, P Brambilla, V Bronzo,
J Cincotti & C Locatelli
Universita` degli Studi di Milano, Facolta` di Medicina
Veterinaria di Milano, via Celoria 10, 20133 (MI) Italy
The aim was to compare quality of induction,
echocardiographic and cardiopulmonary effects of
two different general anaesthesia induction protocols.
Twelve dogs (ASA I-II) were assigned randomly
into two groups. Both groups received a rapid bolus
of propofol (2.2 mg kg)1 IV) immediately followed
by a rapid bolus of dexmedetomidine 3 lg kg)1 IV
(group A) or butorphanol 0MAP, SAP (NIBP) were recorded and 2, 5, 10, 15,
20 minutes after drug administration. Induction
quality, intubation time, additional propofol dose to
achieve intubation, sedation score (Fernandez et al.
2005) and adverse effects were recorded. Echocardiogram
was performed at baseline and immediately
after tracheal intubation. Data were analyzed using
repeated measures ANOVA and Wilcoxon test
(p < 0.05).
Induction quality, intubation time (A: 75 ± 25,
B: 145 ± 66.8 seconds) were statistically different
between groups, HR was statistically lower in group
A compared to baseline (62 ± 23; 101 ± 23), fR
was not statistically different between groups but
lower than baseline in group A, NIBP was statistically
higher in group A and lower in group B
compared to baseline. Body temperature, SpO2,
PE¢CO2 were not statistically different. No apnoea
(>30 seconds) or emesis were recorded. Five group
B dogs required additional propofol (1.1 ± 0.7
mg kg)1 IV) to achieve tracheal intubation. Left
ventricular end-diastolic diameter was statistically
lower in group B and statistically higher in group A
compared to baseline. Cardiac output decrease was
18.5% in group A and 24.4% in group B.
Quality of induction was better in group A.
Echocardiographic parameters varied compared to
baseline in both groups but remained within normal
ranges for adult dogs (Cornell et al. 2004).
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18(3), 311–321..4 mg kg)1 IV (group B)
administered by a blinded operator. Baseline HR,