7
not result in prolonged muscle relaxation (Kumar et al. 2006). The minimal dose
of zoletil for a ten minute anesthesia in cats is 4.2 mg/kgBW (Sendler et al. 1994).
At the dose of 2.5 mg/kgBW, some cats would be more excited rather than
sedated (Forsyth 1995). Sedation of feline patients for diagnostic images is a
standard procedure in many veterinarians (Ferasin et al. 2003).
A previous study by Wilson et al. (1993) in adult rats showed that Zoletil®
is a cardio stimulatory drug that increases the mean arterial blood pressure and
reduces the respiratory depression. A similar research by Hellyer et al. (1989)
showed that Zoletil® resulted in a rapid induction of anesthesia and causes an
increase in heart rate and cardiac output.
MATERIALS AND METHOD
Time and Place
The study was done from November 2011 until April 2012.
Ultrasonography was done at the Division of Surgery and Radiology, Department
of the Clinical, Reproduction and Pathology, Faculty of Veterinary and Medicine,
Bogor Agricultural University.
Animals and Materials
The animals used for this research were nine (9) healthy male Indonesian
Domestic House Cats in the vicinity of the Bogor Agricultural University
weighing between 3.3 – 4.4 kg. Cats were quarantined and acclimatized for one
week where they were given commercial cat food and water ad libittum. On the
first day of quarantine cats were given anthelmintic zipyran plus®. Cats were
excluded if they showed any signs of illness and distress.
Ultrasound console used for this research were: Kaixin ® ultrasound system,
ultrasound scanner (KX5100 Vet), linear probe with frequencies between 5 and
7.5 MHz. Sony video graphic UP-895 MD printer, video camera, shaver, and
gavage. The ultrasonography table had a cut out area.
Materials used for this research were ultrasound gel, Zoletil® (50 mg/ml of
both zolazepam and tiletamine), atropine sulfat (0.25 mg/ml), commercial cat food,
water, syringe (One Med, PT Jaya Mas Medica Industri), and gloves. Zoletil ® was
prepared by adding 5 ml of sterile water to the vial.
Method
Animals
Nine healthy male Indonesian Domestic House Cats weighing between 3.3
and 4.4 kg were kept under controlled conditions prior to ultrasonography. Cats
were put in separate cages and given standard cat food, water (ad libittum) and a
8
sandbox for defecation and urination. Cats were monitored intensively in the
Division of Surgery and Radiology, Department of Clinical, Reproduction and
Pathology, Faculty of Veterinary Medicine, Bogor Agricultural University.
Preparation
A physical examination was performed before anesthesia on the cat’s heart
rate, respiratory rate, body temperature, and body weight. Cats were given
premedication 0.02 mg/kgBW atropine sulfate intramuscularly. After fifteen
minutes, cats were anesthetized using 8 mg/kgBW Zoletil® given intramuscularly.
The target injection organs were the semitendinosus or semimembranosus muscles.
Once the cat was anesthetized, the hair coat at the right lateral axillary area were
clipped and shaved clean.
Echocardiography Technique
Echocardiographic examination was performed from underneath with the
cat on the right lateral recumbence. The probe was positioned at the fourth or fifth
intercostal space. Ultrasonography was performed on the short axis at the
papillary muscle and aorta level on both brightness mode (B-mode) and motion
mode (M-mode). Ultrasonography was performed by one operator using a 7.5
MHz transducer approximately 15 minutes after the cat was anesthetized. Data
using the M-mode were taken until there were three representative data for each
measurements. Pictures were taken using a handycam connected to the monitor.
Data Analysis
Data were performed offline using Image-J© obtained from the National
Institute of Health. The M-mode right parasternal short axis view at the papillary
muscle level was used to measure the left ventricular wall (LVW) thickness
during systole and diastole, the left ventricular internal diameter (LVID) during
systole and diastole, and the interventricular septa wall (IVS) thickness during
systole and diastole. The M-mode right parasternal short axis reading at the aorta
level was used to measure the diameter of the aorta (AO) and the left atrium (LA)
during diastole. Diastolic measurements were taken at the maximal left ventricular
relaxation, while systolic measurements were taken at the maximal left ventricular
contraction. The final value used was the average from the three measurements.
Data were expressed as average ± standard deviation.
Data obtained from the M-mode echocardiography were used to calculate
the LA:AO ratio, left ventricular end diastolic volume (LVED), left ventricular
end systolic volume (LVES), left ventricular stroke volume (SV), left ventricular
cardiac output (CO), ejection fraction (EF), and fractional shortening (FS). Data
obtained were compared to previous studies obtained from literature.
9
Table 3 Equations for the measurement derivates
Parameter
Equation
Left ventricular end diastolic volume (LVED)
Left ventricular end systolic volume (LVES)
Stroke volume (SV)
Cardiac output CO)
Ejection fraction (EF)
Fractional shortening (FS)
LVIDd: left ventricular internal diameter during diastole, LVIDs: left ventricular internal diameter
during systole, HR: heart rate; Source: Boon (2011).
RESULT AND DISCUSSION
Physical Examination
Cats used in this research were nine healthy male Indonesian Domestic
House Cats (DHC). Conform to Edwards (1999), the cats were considered healthy
when their eyes, coat and ears were clean and there were no indication of swollen
gums or physical traumas. Common clinical signs of heart disease in cats such as
respiratory distress (tachypnea and dyspnea), per acute paralysis or paresis
(usually hind limb or forelimb), anorexia, lethargy, and depression were not
observed in the cats used for ultrasonography.
Table 4 Physical examination result of Indonesian Domestic House Cat
Cat ID & Color BW
T
HRa
HRb
RR
(kg)
(ºC)
(bpm)
(bpm)
(per minute)
1 (grey-white)
3.5
38.5
240
128
36
2 (grey-white)
3.0
37.7
202
160
36
3 (grey-white)
3.8
37.7
202
192
28
4 (black)
3.3
37.5
202
156
36
5 (yellow)
4.3
37.4
142
160
28
6 (grey)
3.0
38.0
171
156
44
7 (grey)
3.0
38.5
142
156
32
8 (grey)
3.0
39.0
142
140
36
9 (black-white)
3.3
38.0
174
132
28
Mean ± deviation 3.4 ± 0.4 38.1 ± 0.5 179.7 ± 34.5 153.3 ± 19
33.8 ± 5.3
Reference*
–
37.7–39.4
140–240
20–24
*Source: Eldredge et al. (2008); BW: body weight, T: temperature, HRa: heart rate before
anesthesia, HRb: heart rate after anesthesia, RR: respiratory rate, Dev: deviation standard; bpm:
beats per minute.