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A Clinical Comparative Study of Propofol Total
Intravenous Anesthesia in Dogs
Yi-Chin Tsai, DVM MS; Liang-Yi Wang, PhD; Lih-Seng Yeh, DVM PhD
Propofol total intravenous anesthesia (TIVA) was compared with a well established propofol induced,
isoflurane maintained anesthesia in 271 client-owned canine patients of variable anesthetic
risks. Dogs anesthetized with propofol TIVA showed generally higher values of heart rate
and systemic blood pressure, especially in patients with greater anesthetic risks. Propofol TIVA
appeared to offer lighter level of anesthesia which precludes its application in procedures eliciting
nasal passage stimulation. The time to first regain spontaneous breathing after induction
was significantly longer in dogs maintained with propofol. Uncommon seizure-like tremor episodes
during propofol infusion were also observed in the study.
Key Words: Propofol, total intravenous anesthesia, dogs
Introduction
D
espite the wide adoption of inhalant
anesthesia in veterinary practice,
there are still occasions that a reliable injectable
anesthesia is favorable. Inhalant
anesthesia requires more expensive
equipments and is unsuitable for animals
with conditions such as malignant hyperpyrexia
or in need of particular procedures
such as magnetic resonance imaging
(MRI). Total intravenous anesthesia
(TIVA), which is the induction and maintenance
of anesthesia with intravenous
agents, bears potential advantages for
small animal practitioners, especially when
working in an understaffed and underequipped
environment. TIVA also avoids
some drawbacks of inhalant anesthesia, including
operating room pollution and the
cumbersome anesthetic equipments.
Propofol is an injectable, short-acting,
and rapidly metabolized agent chemically
unrelated to barbiturates or other anesthetic
agents. Propofol anesthesia in dogs
is characterized by its rapid onset, short
duration, rapid metabolism, lack of accumulation
on rapid administration, some
degrees of respiratory depression, and a
From the Department of Veterinary Medicine, College of
Bio-Resources and Agriculture, National Taiwan University,
Taipei 106, Taiwan (Tsai, Yeh); the Graduate Institute
of Epidemiology, College of Public Health, National Taiwan
University, Taipei 106, Taiwan (Wang).
Correspondence: Dr. Lih-Seng Yeh
E-Mail: lsyeh@ntu.edu.tw
rapid smooth recovery from anesthesia. 1,2
The use of propofol for inducing and
maintaining short period of anesthesia has
gained increasing popularity in small animal
practice.
Propofol TIVA has become a widely
adopted technique in human day-case anesthesia
because of the advantages it offers.
In humans, recovery from propofol infusion
is reported to be as rapid as, or even
faster than isoflurane or sevoflurane anesthesia,
and with low incidence of postopertative
nausea and vomiting (PONV). 3
However, large scale systemic study of the
merits of propofol TIVA in canine clinical
anesthesia is not available.
In this study, propofol TIVA was
compared with a well established propofol
induced and isoflurane maintained anesthesia
in canine patients of different status.
The objective of the study was to evaluate
the clinical feasibility and limitations of
propofol TIVA.
Materials and Methods
A total of 271 clients-owned dogs requiring
general anesthesia for surgical or diagnostic
procedures were included in this
study. Dogs were randomly assigned to
two groups of different anesthetic maintenance
protocols. Group-one (Iso group)
dogs received propofol a induction and
52 JVCS, Vol. 1, No. 2, April, 2008

isoflurane b in oxygen maintenance anesthesia.
Group-two (TIVA group) dogs received
propofol total intravenous anesthesia
with oxygen.
Dogs were categorized by the American
Society of Anesthesiologist (ASA)
classification system as ASA 1, 2 or 3, according
to their physical status and hematology
laboratory results. Their breeds, age,
sex, body weight, rectal temperature, heart
rate, co-existing diseases and the nature of
the procedures were recorded before premedication.
A cephalic or lateral
saphenous vein was cannulated for the
administration of propofol. Suitable crystalloid
solutions were also given at the rate
of 10ml/kg/hr during anesthesia.
Acepromazine c (0.05mg/kg of body
weight, IV, with the maximal dose of 3mg)
or diazepam d (0.3mg/kg of body weight,
IV) was given as sedative agent according
to the patients’ behavior and hemodynamic
conditions. Ketoprofen e (1mg/kg of body
weight, IM) was administered in orthropedic
patients preoperatively or intraoperatively
as analgesics. Opioids were not routinely
given as premedication in this study.
It was only given as a rescue remedy as
needed postoperatively.
Dogs were induced with propofol at
an initial intravenous bolus dosage of 1.5-2
mg/kg in about three seconds, and then incremental
doses were administered intermittently
until intubation of the trachea
was possible. Any adverse effect during
induction was recorded, which included
and not limited to cyanosis, neurologic
signs (padding, muscle tremor/twitching,
opisthotnos, vocalization), vomiting and
salivation.
If dogs did not breathe within 30
seconds after intubation, ventilation was
assisted manually and maintained at 3-6
ventilations/min under an appropriate airway
pressure until spontaneous breathing
resumed. The time of onset of spontaneous
breathing was recorded.
Anesthesia was maintained with
isoflurane in oxygen (Iso group) or with
intravenous infusion of propofol using a
syringe pump (TIVA group). Vaporizer
Tsai et al
settings or propofol infusion rates were adjusted
to the lowest by the judgment of
anesthetists to maintain required anesthesia
depth which providing adequate analgesia
and muscle relaxation for the procedure
designated. All dogs were connected
to a semi-closed circle rebreathing anesthetic
machine to provide pure oxygen
with or without isoflurane. Heart rate (HR),
systolic blood pressure (SBP), percent
oxygen saturation, body temperature, capillary
refill time, ventilation rate, vaporizer
setting / propofol infusion rate were recorded
immediately after induction and
every 5 minutes for the duration of anesthesia.
The SBP was obtained by an ultrasonic
Doppler or oscillometric unit. If any
abnormal condition would contribute to
unstable anesthesia or interfered with the
surgical procedures during maintenance,
the case will be recorded and excluded
from the statistical analysis.
Descriptive (categorical) variables
and the incidence of apnea after induction
were analyzed using a chi-square test. Age,
weight, rectal temperature, baseline heart
rates, induction dosage of propofol and
time of regaining spontaneous breathing in
each group were calculated and compared
using two-sample t-test. Paired t-test was
used to compare baseline and postinduction
HR within groups. Continuous
variables (HR, SBP) were analyzed using
two-sample t-test between groups and
were further analyzed according to the
dog’s ASA status, using two-sample t-test
between groups. The data are presented as
mean (SD, standard deviation), and differences
are considered to be statistically significant
at P

eventfully and didn’t show any complication
related to the episode. None of the
dogs had a history of neurological disorders.
A total of three dogs were anesthetized
with propofol TIVA for diagnostic
nasal flushing and rhinoscopy. All of them
attempted to lift the heads during anesthesia.
Even with an increased propofol infusion
rate, the attempt to overcome the irritating
sensation of nasal mucus membrane
was unsuccessful during the procedure.
The condition prevented the diagnostic
procedures from being carried out and the
anesthetist had to shift to isoflurane for a
smoother maintenance. None of the five
dogs underwent diagnostic nasal flushing
and rhinoscopy in the Iso group developed
the same condition.
The hemodynamic data of the eight
cases above mentioned could no longer
represent the exact manifestation in their
group. They were excluded in the statistical
analysis. A total of 263 dogs were included
in the statistical analysis of the
study.
Descriptive variables were tested to
ensure the validity of database and the results
are shown in Table 1. There are no
Table 1. Description of two groups.*
Propofol TIVA in Dogs
Variables Iso group(n=162) TIVA group(n=101)
Gender (male / female) 80 / 82 42 / 59
Surgical procedures ( A / B / C / D) 21 / 104 / 21 /16 11 / 76 / 12 / 2
Abdominal cavity opened / non-opened 58 / 104 40 / 61
Tranquilizers (Acp / Dia) 63 / 99 39 / 62
ASA status ( 1 / 2 / 3 ) 54 / 83 / 25 35 / 50 / 16
Surgical procedures A= Orthopedic, B= Soft tissue, C= Oral, D= others
Tranquilizers Acp= Acepromazine, Dia= Diazepam.
*Statistically significant differences were not found.
Table 2. Age, weight, rectal temperature, baseline heart rate and induction dosage of
propofol, expressed as mean (SD).
Variables Iso group(n=162) TIVA group(n=101)
Age (years) 7.5 (4.3) 7.7 (4.0)
Weight (Kg) 11.3 (9.0)* 7.8 (6.0)*
Rectal temperature (℃) 38.8 (0.6) 38.8 (0.6)
Baseline heart rate (beats/min) 125.0 (27.8) 125.0 (25.0)
Induction dosage of propofol (mg/kg) 5.0 (1.5) 5.3 (3.6)
*Significant difference between groups (p< 0.05)
statistically significant differences between
the two groups with respect to gender distribution,
categorized surgical procedures,
whether the abdominal cavity had been
opened, patient’s ASA status, and the
tranquilizers (acepromazine or diazepam)
given.
Mean age, mean body weight, mean
baseline rectal temperature, mean baseline
HR and mean propofol induction dosages
(mg/kg) in each group are shown in Table
2. No statistically significant differences
were found between the groups except the
mean body weight.
During propofol induction, adverse
effects were observed in a total of 53 dogs
(20%). Which included neurological signs
(padding, muscle tremor/twitching…),
cyanosis and other adverse effects (vomiting
or salivation) in 37 (14%), 13 (5%) and
3 (1%) of dogs, respectively. The 13 dogs
developed cyanosis before intubation were
all with concurrent cardiovascular and/or
pulmonary disorders. After propofol induction,
the incidence of apnea was 67%
in the Iso group and 73% in the TIVA
group, with no statistically difference.
However, animals in the Iso group regained
spontaneous breathing significantly
54 JVCS, Vol. 1, No. 2, April, 2008

earlier than the TIVA group. [4.5(5.4)
minutes versus 7.8(11.3) minutes, respectively;
P< 0.05]
Statistical evaluation of HR and SBP
were carried out for the first 90 minutes of
the anesthesia. Beyond which point the
small data number collected was no longer
feasible for statistical analysis (sample
numbers

Propofol TIVA in Dogs
Figure 2A to 2C-Changes in HR
(mean ± SD) over a 90 minutes period
in two anesthetic groups with different
ASA status.
#: significantly different between two
groups, Post-ind: right after induction.
56 JVCS, Vol. 1, No. 2, April, 2008
A
B
C

apnea, and endotracheal intubation should
be routinely performed for ventilation support.
Neurological adverse effects during
propofol administration were widely documented
and with variable incidence in
researches. 11 In a previous study, muscle
tremor was developed in as high as 50% of
dogs at 20-30 minutes after propofol infusion.
12 However, most neurological complications
were documented during induction
or recovery phases of anesthesia. 11,12
In this study, neurological signs usually
appeared only for a short period of time
and would not interfere with the diagnostic
or surgical procedures. The incidence of
neurological signs during propofol induction
was 14% (37/263), including paddling,
muscle tremor/twitching, opisthotnos and
vocalization.
Seizure-like phenomenon (SLP) related
to propofol was discussed in a number
of human case reports and may develop
in patients with or without epilepsy history.
13 However, the SLP with propofol infusion
has not been systemically studied
and was only documented in uncontrolled
observations in human studies. During
anesthetic maintenance of the present
study, seizure-like generalized tremor was
observed in five of 109 dogs in the TIVA
group and none in the Iso group. The five
cases were without any neurological medical
history. The seizure was discontinued
immediately after changing propofol infusion
into isoflurane maintenance. This
Tsai et al
phenomenon indicated a disrupted central
nervous system and prevented the procedures
from being carried on. Though the
incidence of generalized tremor in our
TIVA group had been low (< 5 %), practitioners
should still be aware of the symptom.
If the condition is uncontrollable, the
switch to inhalant maintenance is recommended.
Propofol induction associated cyanosis
was observed in 13 dogs (5%), which
were all with co-existing cardio/pulmonary
diseases. Though the incidence was low
and the cyanosis was readily resolved once
endotracheal tube was placed and manually
ventilated, we believe that a preoxygenation
before propofol induction may be
beneficial for patients with cardio/pulmonary
diseases.
Propofol causes a fall in arterial pressure,
but due to its central effects and baroreflex
sensitization, it also causes a reduction
in the heart rate, which is normally
compensatedly increased associated with
hypotension. 14,15 In the present study, the
first detected HR after propofol induction
was significantly lower in the TIVA group.
This can be explained by the effect of continuing
propofol infusion. The HR was
gradually returned to baseline value and
was elevated at surgical stimulations. Although
the falling in heart rate after induction
didn’t require medical intervention,
anesthetists are advised to closely and continuously
monitor post-induction HR during
propofol TIVA.
Figure 3-Changes in SBP (mean ±
SD) over a 90 minutes period in two
anesthetic groups.
#: significantly different between two
groups, Post-ind: right after induction.
JVCS, Vol. 1, No. 2, April, 2008 57

Propofol TIVA in Dogs
Figure 4A to 4C-Changes in SBP
(mean ± SD) over a 90 minutes period
in two anesthetic groups according
to different ASA status.
#: significantly different between two
groups, Post-ind: right after induction.
58 JVCS, Vol. 1, No. 2, April, 2008
A
B
C

The hemodynamic effects of an anesthetic
agent play an important role in patients’
physical condition during and after
anesthesia. In animals with severe systemic
diseases, even the lightest levels of
anesthesia may be stressful to the cardiovascular
system, and will be associated
with increased morbidity and mortality.
Isoflurane provides progressive depression
of the central nervous system, as well as
inducing cardiovascular and respiratory
depression in a dose-dependent fashion. 16
Propofol had been reported to maintain
better arterial blood pressure than isoflurane
with a similar or lower HR. 17,18 In the
present study, propofol TIVA did produced
higher SBP throughout the anesthesia.
And it also maintained equal or higher
HR during the whole length of procedures
compared with propofol induced, isoflurane
maintained anesthesia, which is different
from previous literatures. In dogs
with higher anesthetic risk (ASA 2 and
ASA 3), propofol TIVA produced even
higher SBP during maintenance. We suggest
that it would be more appropriate to
consider propofol TIVA over propofolisoflurane
anesthesia in patients with moderate
to severe systemic disease for less
compromised hemodynamic performance.
Conculsion
Both the propofol induced, isoflurane
maintained anesthesia and the propofol
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TIVA protocols offered clinical feasibility.
Propofol TIVA provided adequate anesthesia
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is recommended as a safe and valid general
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of anesthetic risk factors. However, propofol
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anesthesia is recommended.
Acknowledgement
The authors acknowledge the anesthetists
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during anesthesia.
Footnotes
a propofol®, Lipuro, B Braun, Melsungen, AG
b
isoflurane®, Forane, Abbott Ltd, Queenborough, Kent,
England
c
acepromazine®, Acepromazine Maleate, Veclco inc, St.
Joseph, MO
d
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e
ketoprofen®, Febin, Tai Yu Ltd, Taipei, Taiwan
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