https://doi.org/10.52973/rcfcv-e34472
Received: 19/06/2024 Accepted: 31/07/2024 Published: 30/11/2024
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Revista Científica, FCV-LUZ / Vol. XXXIV, rcfcv-e34472
ABSTRACT
Hemodynamic parameters are clinical indicators used in Human and
Veterinary Medicine to assess the general health status of patients
and identify potential risks. Alpha–2 adrenoceptor agonists, such
as Medetomidine and Dexmedetomidine, are known to produce
dose–dependent premedication ranging from mild to profound
and have signicant cardiovascular effects. This study aimed to
evaluate the effects of these commonly used alpha–2 adrenoceptor
agonists on hemodynamic parameters, particularly blood pressure.
To achieve this, 100 cats aged between 6 months and 7 years old ere
randomly divided into two groups. Hemodynamic parameters were
analyzed both before and 5 minutes after premedication with either
Medetomidine or Dexmedetomidine. Although there were signicant
changes in hemodynamic parameters before and after premedication
within each group, no statistically significant differences were
observed between the Medetomidine and Dexmedetomidine groups.
In conclusion, the effects of equivalent doses of Medetomidine and
Dexmedetomidine on hemodynamic parameters were found to be
similar in cats.
Key words: Blood Pressure; Dexmedetomidine; Medetomidine;
heart rate; hemodynamic parameters
RESUMEN
Los parámetros hemodinámicos son indicadores clínicos,
utilizados en la Medicina Humana y Veterinaria para evaluar el
estado general de salud de los pacientes e identificar posibles
riesgos. Los agonistas de los adrenoreceptores alfa–2, como la
Medetomidina y la Dexmedetomidina, son conocidos por producir
una premedicación dependiente de la dosis que varía de leve a
profunda y tienen efectos cardiovasculares signicativos. Este
estudio tuvo como objetivo evaluar los efectos de estos agonistas
de los adrenoreceptores alfa–2 comúnmente utilizados en los
parámetros hemodinámicos, especialmente la presión arterial. Para
conseguirlo, se dividieron aleatoriamente en dos grupos 100 gatos
de edades comprendidas entre 6 meses y 7 años. Se analizaron los
parámetros hemodinámicos tanto antes como 5 minutos después
de la premedicación con Medetomidina o Dexmedetomidina. Aunque
hubo cambios signicativos en los parámetros hemodinámicos
antes y después de la premedicación dentro de cada grupo, no se
observaron diferencias estadísticamente signicativas entre los
grupos estudiados. En conclusión, se encontró que los efectos de
dosis equivalentes de Medetomidina y Dexmedetomidina sobre los
parámetros hemodinámicos eran similares en los gatos.
Palabras clave: Presión arterial; Dexmedetomidina; Medetomidina;
frecuencia cardíaca; parámetros hemodinámicos
A comparative analysis of the effects of Medetomidine and
Dexmedetomidine on hemodynamic parameters in cats
Technical note
Un análisis comparativo de los efectos de la Medetomidina y la Dexmedetomidina sobre los
parámetros hemodinámicos en gatos
Nota técnica
Eylem Bektaş Bilgiç
Istanbul University–Cerrahpasa, Faculty of Veterinary Medicine, Department of Surgery. Istanbul, Türkiye
*Correspondence author: eylem.bilgic@iuc.edu.tr
Hemodynamic parameters in cats / Bektaş Bilgiç ___________________________________________________________________________________
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INTRODUCTION
Hemodynamic parameters are clinical indicators in both Human
and Veterinary Medicine that provide information about a patient’s
general health status and potential risks. These parameters reect
blood ow in the vascular system, with heart rate and blood pressure
being the primary hemodynamic measures [1].
Heart rate is a non–specic parameter that is typically measured by
auscultation at rest, palpation of the heart’s apex beat, or palpation
over an artery [2]. Heart rate is a crucial determinant of cardiac
output. Changes in heart rate are sensitive indicators of a patient’s
physical condition [3, 4].
Arterial blood pressure (ABP) is a vital monitoring tool used in
anesthetized animals and in the emergency room to assess a patient’s
hemodynamic status [5, 6]. ABP can be measured indirectly or directly
[4, 5, 6, 7]. ABP is measured indirectly with a sphygmomanometer [8].
Indirect ABP measurement methods are widely used because they are
easy and noninvasive [9]. Direct arterial blood pressure measurement
is the most accurate method and is therefore considered the gold
standard of blood pressure measurement [6, 10, 11]. The need for
experience, equipment and complications limit the indication for
use in high–risk patients [11].
Alpha–2 adrenoceptor agonists produce mild to profound
premedication depending on the dose. They have analgesic and
muscle relaxant properties and are known for their significant
cardiovascular effects, including second–degree heart block,
bradycardia, and vasoconstriction. Dexmedetomidine is the dextro
isomer of Medetomidine and is approximately twice as potent.
Both Medetomidine and Dexmedetomidine cause more prolonged
vasoconstriction and hypertension compared to Xylazine. This
prolonged hypertension leads to a deeper reex bradycardia than
seen with other alpha–2 adrenoceptor agonists [10, 12, 13, 14, 15, 16].
This study comparatively evaluated the effects of medetomidine
and dexmedetomidine on hemodynamic parameters, particularly
blood pressure.
MATERIAL AND METHODS
This study involved a total of 100 male and female cats (Felis
catus) between 6 months and 7 years old aged, brought to the
Otorhinolaryngology Clinic of Istanbul University–Cerrahpasa Faculty
of Veterinary Science, Department of Surgery, between 2018 and
2022. These cats were indicated for Ventral Bulla Ostectomy (VBO)
based on the examinations performed.
Laboratory investigations and radiographic examinations (Ecoray
Veterinary Digital X–ray System and Ecoray Ecoview System, Hasvet,
Turkey) were conducted as part of routine anesthesia preparation.
Hemogram (VH5R Veterinary Hematology Analyzer, Hasvet, Turkey)
and preanesthetic biochemistry panels ( FUJI DRI–CHEM NX700V Fully
Automatic Veterinary Biochemistry Analyzer, Hasvet, Turkey) were
reviewed for all patients. Right and left laterolateral and dorsoventral
thoracic radiographs were obtained to evaluate the airway, pulmonary
parenchyma, mediastinum, and pleural cavity before anesthesia.
Patients with laboratory and radiological examination results
considered normal were included in the study. Before taking the
patient to the operating room, the owner was asked the following
questions: When did the patient last eat? When did the patient last
drink water? Has the patient undergone surgery before? Were there
any complications related to anesthesia? Is the patient currently on
any medication? Has the patient recently had any illnesses? Has the
patient experienced vomiting, diarrhea, or loss of appetite in the
past week? Is the patient in estrus? The responses were recorded.
Animals with no food restriction, those with general health issues,
and those in estrus had their surgeries canceled and were excluded
from the study.
Patients with ASA degree I and II anesthesia risk, based on
physical, laboratory, and radiological examinations, were included
in the study. The 100 patients were randomly divided into two groups
of 50 each. Each patient underwent a preanesthetic examination
before anesthesia and medication administration. Palpation of
the mandibular, lateral retropharyngeal, prescapular, and popliteal
lymph nodes, as well as the thoracic and abdominal regions, was
performed for each patient. Mucous membrane color, capillary rell
time (CRT), and body temperature were assessed and recorded.
Heart rate and respiratory rate were measured with a stethoscope
(Littmann 5870 Classic III Stetoskop, 3M, Turkey). Systolic blood
pressure (SBP), diastolic blood pressure (DBP), mean arterial
pressure (MAP), and pulse rate were measured with an automatic
digital sphygmomanometer (Pettrust, noninvasive blood pressure
monitor, BioCARE, United Kingdom).
After the preanesthetic examination, preemptive subcutaneous
administration of butorphanol (0.4 mg·kg
-1
) (Butorphanol®, Richter
Pharma AG, Austria) was performed using the same protocol in
both groups. Ten minutes (min) after butorphanol administration,
intravenous access was established via the cephalic vein or saphenous
vein using a 22– or 24–gauge angiocath (Intraket, Bıcakcilar, Turkey).
For premedication, the rst group received Medetomidine HCl (40
μg·kg
-1
) (Tomidin®, ALIVIRA) IV, while the second group received
Dexmedetomidine HCl (20 μg·kg
-1
) (Hipnodex®, Haver Farma, Turkey) IV.
Following premedication, patients were immobilized and connected
to a bedside monitor (Multiparameter Veterinary Monitor, GT9003E,
MVM, Turkey).
At the fth minute following premedication, mucous membrane
color, CRT and body temperature, SBP, DBP, MAP and pulse rate were
measured again and recorded (Pettrust, noninvasive blood pressure
monitor, BioCARE, United Kingdom).
The data obtained in this study were analyzed with the licensed
SPSS 27 package program. Frequency analysis, frequency (n) and
percentage (%) values of the groups were calculated. Descriptive
statistics such as arithmetic median (Med) and interquartile range (IQR)
were also included in hypothesis testing. Shapiro Wilks test was used
to search whether the variables were from a normal distribution due to
the number of units. While interpreting the results, 0.05 was used as
the signicance level and it was stated that the variables did not come
from a normal distribution if P<0.05. Mann Whitney U test, one of the
2independent group comparison tests, was used for scale scores that
were not suitable for normal distribution. Wilcoxon sign test was used
to examine the difference between dependent continuous variables.
In the interpretation of the results, 0.05 was used as the signicance
level and it was stated that there was a signicant difference if P<0.05
and there was no signicant difference if P>0.05.
RESULTS AND DISCUSSION
This study included 100 cats, with the youngest patient being 6
months old and the oldest being 7 years old, resulting in an average
TABLE I
Comparison of hemodynamic parameters during
preanesthetic period and after premedication
Variable N Med SS Med Rank z P
Preanesthetic Heart Rate 100 162.94 42.67 53.54
-8.254 0.001*
Heart Rate After Premedication 100 95.23 27.87 15.56
Preanesthetic Pulse 100 131.48 39.20 54.90
-7.742 0.001*
Pulse After Premedication 100 83.13 21.73 21.04
Preanesthetic SBP 100 170.29 186.15 44.00
-2.109 0.035*
SBP After Premedication 100 163.94 36.62 55.05
Preanesthetic DBP 100 98.74 36.57 50.61
-3.287 0.001*
DBP After Premedication 100 117.56 40.92 50.45
Preanesthetic MAP 100 116.49 32.17 46.24
-3.435 0.001*
MAP After Premedication 100 132.45 34.64 52.60
Preanesthetic CRT 100 1.00 0.00 0.00
-1.732 0.083
CRT After Premedication 100 1.03 0.17 2.00
*
P<0.05; z=Wilcoxon sign test
TABLE II
Comparison of hemodynamic parameters during preanesthetic
period and after premedication in medetomidine group
Variable N Med SS Med Rank z P
Preanesthetic Heart Rate 50 164.28 47.77 27.57
-5.824 0.001*
Heart Rate After Premedication 50 90.74 25.81 6.90
Preanesthetic Pulse 50 140.51 41.43 27.31
-5.710 0.001*
Pulse After Premedication 50 85.68 22.08 9.20
Preanesthetic SBP 50 153.38 36.62 21.52
-1.376 0.169
SBP After Premedication 50 165.44 38.99 28.89
Preanesthetic DBP 50 97.58 34.59 21.84
-2.148 0.032*
DBP After Premedication 50 116.44 38.99 27.74
Preanesthetic MAP 50 115.52 31.83 19.29
–2.245 0.025*
MAP After Premedication 50 132.02 37.94 30.00
Preanesthetic CRT 50 1.00 0.00 0.00
–1.001 0.317
CRT After Premedication 50 1.02 0.14 1.00
*P<0.05; z=Wilcoxon sign test
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age of 2.32 years. In terms of gender, the study included nearly equal
numbers of male (51) and female (49) cats. It was recorded that 65%
of the 100 patients included in the study were intact, and 35% were
sterile. The average body weight of the patients was calculated to
be 3.32 kg, with a minimum value of 1.3 kg and a maximum value of
5.75 kg. When the entire population was assessed, it was recorded
that 94 patients were mixed breeds, while the remaining 6 patients
consisted of 4 British Shorthairs, 1 Chinchilla, and 1 Himalayan cat.
This study was conducted between 2018 and 2022 and was carried
out during the COVID–19 pandemic, a period marked by many global
changes. When analyzing hemodynamic responses by year, it was
observed that cases evaluated during 2020–2021 showed similar
results to those evaluated in other years; however, the number of
cases in these two years was lower (a total of 25).
Heart rate was 162.94 bpm in the preanesthetic period and
95.23 bpm after premedication. z: -8.254 and P:0.001, there was
a statistically significant difference between heart rate in the
preanesthetic period and after premedication (P<0.05).
Pulse rate was 131.48 bpm in the preanesthetic period and 83.13 bpm
after premedication. z: -7.742 and P:0.001, but there was a statistically
signicant difference between pulse rate values in the preanesthetic
period and after premedication (P<0.05).
SBP was 170.29 mmHg in the preanesthetic period and 163.94
mmHg after premedication. z -2.109 and P: 0.035, but there was
a statistically significant difference between SBP values in the
preanesthetic period and after premedication (P<0.05).
DBP was 98.74 mmHg in the preanesthetic period and 117.56 mmHg
after premedication. z -3.287 and P: 0.001, but there was a statistically
signicant difference between DBP values in the preanesthetic period
and after premedication (P<0.05).
MAP was 116.49 mmHg in the preanesthetic period, 132.45 mmHg
after premedication, z: -3.435 and P: 0.001. There was a statistically
signicant difference between MAP values in the preanesthetic period
and after premedication (P<0.05).
CRT was <1.00 seconds in the preanesthetic period and <1.03
seconds after premedication, z: -1.732 and P: 0.083. There was no
statistically signicant difference between CRT in the preanesthetic
period and after premedication (P<0.05) (TABLE I).
When the medetomidine group was evaluated, the preanesthetic
heart rate was 164.28 bpm and 90.74 bpm after premedication. z
-5.824 and P: 0.001, there was a statistically signicant difference
between the heart rate values during the preanesthetic period and
after premedication in the medetomidine group (P<0.05).
Pulse rate was 140.51 bpm in the preanesthetic period, 85.68 bpm
after premedication, z: -5.710 and P: 0.001. In the medetomidine group,
there was a statistically signicant difference between pulse rate
values in the preanesthetic period and after premedication (P<0.05).
SBP was 153.38 mmHg in the preanesthetic period, 165.44 mmHg
after premedication, z: -1.376 and P: 0.169. In the medetomidine
group, there was no statistically signicant difference between SBP
values in the preanesthetic period and after premedication (P>0.05).
DBP was 97.58 mmHg in the preanesthetic period, 116.44 mmHg
after premedication, z: -2.148 and P: 0.032. In the medetomidine
group, there was a statistically signicant difference between DBP
values in the preanesthetic period and after premedication (P<0.05).
MAP was 115.52 mmHg in the preanesthetic period, 132.02 mmHg
after premedication, z: -2.245 and P: 0.025. In the medetomidine
group, there was a statistically signicant difference between MAP
values in the preanesthetic period and after premedication (P<0.05).
CRT preanesthetic <1.00 seconds, <1.02 seconds after
premedication, z: -1.001 and P: 0.317. In the medetomidine group,
there was no statistically signicant difference between CRT values
during the preanesthetic period and after premedication (TABLE II).
In the dexmedetomidine group, heart rate was 161.60 bpm in the
preanesthetic period, 99.72 bpm after premedication, z: -5.894
and P: 0.001. There was a statistically significant difference
between heart rate values in the preanesthetic period and after
premedication (P<0.05).
TABLE III
Comparison of hemodynamic parameters in dexmedetomidine
group during preanesthetic period and after premedication
Variable N Med SS Med Rank z P
Preanesthetic Heart Rate 50 161.60 37.33 26.55
-5.894 0.001*
Heart Rate After Premedication 50 99.72 29.35 9.00
Preanesthetic Pulse 50 122.46 34.97 27.98
-5.189 0.001*
Pulse After Premedication 50 80.58 21.29 12.50
Preanesthetic SBP 50 187.20 260.93 23.18
-1.680 0.093
SBP After Premedication 50 164.44 34.42 27.05
Preanesthetic DBP 50 99.90 38.77 32.13
-2.433 0.015*
DBP After Premedication 50 118.82 40.00 23.41
Preanesthetic MAP 50 117.46 32.79 30.00
-2.679 0.007*
MAP After Premedication 50 132.88 31.38 24.08
Preanesthetic CRT 50 1.00 0.00 0.00
-1.414 0.157
CRT After Premedication 50 1.04 0.19 1.50
*P<0.05; z=Wilcoxon sign test
Hemodynamic parameters in cats / Bektaş Bilgiç ___________________________________________________________________________________
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Pulse rate was 122.46 bpm in the preanesthetic period, 80.58 bpm
after premedication, z: -5.189 and P: 0.001. There was a statistically
signicant difference between pulse rate values in the preanesthetic
period and after premedication (P<0.05).
SBP was 187.20 mmHg in the preanesthetic period, 164.44 mmHg
after premedication, z: -1.680 and P: 0.093. There was no statistically
signicant difference between SBP values in the preanesthetic period
and after premedication.
DBP was 99.90 mmHg in the preanesthetic period, 118.82 mmHg
after premedication, z: -2.433 and P: 0.015. There was a statistically
signicant difference between DBP in the preanesthetic period and
after premedication (P<0.05).
MAP was 117.46 mmHg in the preanesthetic period, 132.88 mmHg
after premedication, z: -2.679 and P: 0.007. There was a statistically
signicant difference between mean arterial pressure values in the
preanesthetic period and after premedication (P<0.05).
CRT was <1.00 s in the preanesthetic period, <1.04 after
premedication, z: -1.414 and P: 0.157. There was no statistically
signicant difference between CRT in the preanesthetic period and
after premedication (TABLE III).
In the preanesthetic period, the pulse rate was 138.00 bpm
(IQR 41.43) in the medetomidine group and 124.50 bpm (IQR 34.97)
in the Dexmedetomidine group, with a z–score of -2.027 and P–
value of 0.043. A statistically signicant difference in pulse rate
between the two groups was observed during the preanesthetic
period (P<0.05), with the Medetomidine group showing a higher
pulse rate. After premedication, the pulse rate was 86.50 bpm (IQR
22.08) in the Medetomidine group and 76.50 bpm (IQR 21.29) in the
Dexmedetomidine group, with a z–score of -1.534 and P–value of
0.125. There was no statistically signicant difference in pulse rate
between the two groups after premedication.
In the Medetomidine group, SBP was 148.00 mmHg (IQR 36.62),
and in the Dexmedetomidine group, it was 152.00 mmHg (IQR
260.93), with a z–score of -0.014 and P–value of 0.989 during the
preanesthetic period. There was no statistically signicant difference
in SBP between the two groups before premedication. After
premedication, SBP in the Medetomidine group was 161.00 mmHg
(IQR 39.00) and in the Dexmedetomidine group it was 158.00 mmHg
(IQR 34.42), with a z–score of -0.138 and P–value of 0.891. There was
no statistically signicant difference in SBP between the two groups
after premedication.
In the Medetomidine group, DBP was 102.50 mmHg (IQR 34.59),
and in the Dexmedetomidine group, it was 102.00 mmHg (IQR 38.77),
with a z–score of -0.159 and P–value of 0.874 during the preanesthetic
period. There was no statistically signicant difference in DBP between
the two groups before premedication. After premedication, DBP in
the Medetomidine group was 116.00 mmHg (IQR 42.19), and in the
Dexmedetomidine group, it was 118.50 mmHg (IQR 40.00), with a z–score
of -0.048 and P–value of 0.962. There was no statistically signicant
difference in DBP between the two groups after premedication.
During the preanesthetic period, the MAP was 117.50 mmHg (IQR
31.83) in the Medetomidine group and 112.50 mmHg (IQR 32.79) in the
Dexmedetomidine group, with a z–score of -0.091 and P–value of 0.929.
There was no statistically signicant difference in preanesthetic
MAP between the two groups. After premedication, the MAP was
130.00mmHg (IQR 37.95) in the Medetomidine group and 131.50 mmHg
(IQR 31.38) in the Dexmedetomidine group, with a z–score of -0.442
and P–value of 0.657. Similarly, there was no statistically signicant
difference in MAP values between the two groups after premedication.
During the preanesthetic period, CRT was <1.00 s (IQR 0.00) in both
the Medetomidine and Dexmedetomidine groups, with z–scores of
0 and P–values of 1. There was no statistically signicant difference
in CRT between the two groups. After premedication, CRT remained
<1.00 s, with an IQR of 0.14 in the Medetomidine group and an IQR of
0.20 in the Dexmedetomidine group, resulting in z–scores of -0.583
and a P–value of 0.561. Similarly, there was no statistically signicant
difference in CRT between the two groups after premedication.
During the preanesthetic period, normal mucous membrane color
was observed in 98% of the Medetomidine group and 96% of the
Dexmedetomidine group. Pale mucous membrane color was noted
in 2% of participants in both groups. Hyperemic mucous membrane
color was absent in the Medetomidine group but observed in 2% of
the Dexmedetomidine group (P=0.603). There was no statistically
significant difference between the two groups in terms of
preanesthetic mucous membrane color.
After premedication, normal mucous membrane color was observed
in 96% of the Medetomidine group and 94% of the Dexmedetomidine
When comparing the data from both groups, the heart rate in
the medetomidine group was 160.00 bpm (IQR 47.77), while in the
dexmedetomidine group it was 162.00 bpm (IQR 37.33), with z–score
of -0.111 and P–value of 0.912. There was no statistically signicant
difference between the two groups in terms of heart rate during the
preanesthetic period. Following premedication, the heart rate was
88.50 bpm (IQR 25.81) in the Medetomidine group and 96.50 bpm (IQR
29.35) in the Dexmedetomidine group, with z–score of -1.765 and
P–value of 0.078. Again, there was no statistically signicant difference
between the two groups in terms of heart rate after premedication.
TABLE IV
Comparison of Hemodynamic Parameters Between Groups
Variable
Group
Mann Whitney U Test
Medetomidine Dexmedetomidine
Med. IQR Med. IQR z P
Preanesthetic Heart Rate 160.00 47.77 162.00 37.33 -0.111 0.912
Heart Rate After Premedication 88.50 25.81 96.50 29.35 -1.765 0.078
Preanesthetic Pulse 138.00 41.43 124.50 34.97 -2.027 0.043*
Pulse After Premedication 86.50 22.08 76.50 21.29 -1.534 0.125
Preanesthetic SBP 148.00 36.62 152.00 260.93 -0.014 0.989
SBP After Premedication 161.00 39.00 158.00 34.42 -0.138 0.891
Preanesthetic DBP 102.50 34.59 102.00 38.77 -0.159 0.874
DBP After Premedication 116.00 42.19 118.50 40.00 -0.048 0.962
Preanesthetic MAP 117.50 31.83 112.50 32.79 -0.091 0.929
MAP After Premedication 130.00 37.95 131.50 31.38 -0.442 0.657
Preanesthetic CRT 1.00 0.00 1.00 0.00 0 1
CRT After Premedication 1.00 0.14 1.00 0.20 -0.583 0.561
n % n % P
Preanesthetic Normal 49 98.00 48 96.00
0.603
Mucous Membrane Pale 1 2.00 1 2.00
Color Hyperemic 0 0.00 1 2.00
After Premedication Normal 48 96.00 47 94.00
0.211Mucous Membrane Pale 2 4.00 1 2.00
Color Hyperemic 0 0.00 2 4.00
*
P<0.05; chi–square test
_____________________________________________________________________________Revista Cientifica, FCV-LUZ / Vol. XXXIV, rcfcv-e34472
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group. Pale mucous membrane color was noted in 4% of the
Medetomidine group and 2% of the Dexmedetomidine group. Hyperemic
mucous membrane color was absent in the Medetomidine group but
observed in 4% of the Dexmedetomidine group (P=0.211). There was no
statistically signicant difference between the two groups in terms of
mucous membrane color after premedication (TABLE IV).
In this study, the mean preanesthetic heart rate was calculated
as 162.94 bpm and it was noted to be within normal limits according
to the literature [4, 17]. It is considered normal for cats under stress
to have a heart rate of up to 240 bpm [18]. In addition, values above
240 bpm are dened as sinus tachycardia [19]. In this study, the
maximum value of preanesthetic heart frequency was 280 bpm and
was considered as stress–induced sinus tachycardia [18, 19]. The
pulse rate monitored with a noninvasive blood pressure monitor was
131.48 bpm. Normal pulse rate is in the range of 100–160 bpm [20] and
pulse rate results were in parallel with the literature [20] and within
normal limits. The maximum pulse rate among the cases was 234
bpm, which was above normal limits, and the pulse rate up to 240 bpm
was within acceptable limits [18]. The reference ranges of SBP are
80–120 mmHg [21], 80–140 mmHg [4, 22], 90–160 [23] 120–170 mmHg
[24], 115–162 mmHg [25] but they differ in the sources. In the study,
SBP was 187.20 mmHg in the preanesthetic period, was found to be
above all reference values reported in the literature [4, 21, 22, 23, 24,
25, 26]. DBP was 98.74 mmHg in the preanesthetic period. Although
the normal DBP reference range is 45–55 mmHg [23], 55–75 mmHg
[21, 22], 70–120 [24], 74–91 mmHg [25], this results were above the
reference range according to some literatures [21, 22, 23, 24, 25]and
within normal limits according to Clark [24] MAP was 116.49 mmHg
in the preanesthetic period, which was above the reference range,
although the normal values of 60–80 mmHg [23], 60–100 mmHg [21,
22], 96–106 mmHg [25] differ between the literatures.
Respiratory rate, SBP, DBP and MAP are parameters directly
affected by stress [4, 27]. In this study, hemodynamic parameters
were above the reference ranges in the preanesthetic period,
suggesting that the patients were exposed to stress. The fact that
the hospital is located far from the city center, the patients were
brought by motor vehicles, the patients mostly waited in line when
they arrived and interacted with other cats and dogs visually or audibly
during this waiting period was seen as the main factor of this stress.
In addition to this, it was stated by many patient owners that even
getting the cats, which constituted the material of the study, into the
carrying bag was a source of stress in itself. In addition, especially
considering that preanesthetic measurements were performed while
the patient was awake, it was thought that the reactions of many
cats to these measurements also contributed to stress, and this idea
was in line with the results of Qimby et al. [27] and Haskins et al. [4].
Heart rate refers to the number of heart beats per minute, whereas
pulse denotes the number of distinct beats felt in an artery due to
increased blood pressure. Essentially, pulse is a reection of heart
rate [28]. The study results indicated that the mean heart rate
Hemodynamic parameters in cats / Bektaş Bilgiç ___________________________________________________________________________________
6 of 8
(162bpm) and pulse rate (131 bpm) were distinct from each other,
yet both remained within normal ranges. Interestingly, contrary to
results in the literature [28], the pulse rate did not precisely mirror
the heart rate. This discrepancy could be attributed to the timing
disparity between heart rate and pulse measurements, or it may
relate to stress or movement induced while restraining the animal
during the heart rate assessment.
Alpha–2 adrenoreceptor agonists have been reported to signicantly
impact cardiovascular function, often causing bradycardia [29,
30]. A heart rate below 100 bpm [31] or 90 bpm [4] is referred to
as bradycardia. In this study, heart frequency was measured as
95.23 bpm and pulse rate as 83.13 bpm after premedication and it
was found that the pulse rate was in parallel with the literature [29,
30] and decreased signicantly. Considering the heart rate values,
bradycardia, one of the cardiovascular dysfunctions mentioned by
Nicolas et al. [29] and Sinclair [30], which is within the reference
range according to the literatures [4, 31], did not occur. However,
signicant bradycardia was observed upon evaluating the pulse after
premedication. In cats experiencing a progressive decrease in blood
pressure, the metatarsal pulse may vanish, and obtaining a femoral
pulse becomes dicult in severe hypotension [32]. The discrepancy
between pulse and heart rate values in the study was attributed to
the potential disappearance of the metatarsal pulse, as noted in the
results of Reineke et al. [32], or irregular beats due to arrhythmias
induced by alpha–2 agonists that may not be palpable in peripheral
vessels. It was concluded that assessing the pulse by palpating the
femoral artery during premedication of small animals like cats may
be more reliable than using a digital sphygmomanometer.
Alpha–2 adrenoceptor agonists immediately affect the cardiovascular
system by inducing peripheral vasoconstriction through alpha–2
adrenoreceptors in the peripheral vasculature, resulting in increased
blood pressure [16]. In this study, DBP and MAP values increased after
premedication in parallel with the literature [16]. In another study,
it was observed that systolic, diastolic, and mean arterial pressure
values increased following administration of alpha–2 agonists [33].
After premedication, the blood pressure results were consistent with
those reported by Johard et al. [33], showing an increase in DBP and
MAP values. However, a decrease in SBP was observed, which has not
been reported in the literature before. This slight decrease in SBP,
independent of DBP and MAP values, was attributed to the reduction
in heart rate and cardiac output resulting from the central nervous
system suppression induced by alpha–2 agonists.
The normal MAP value is in the range of 60–100 mmHg [8, 34]. The
blood pressure in vital organs is automatically regulated within the
range of 60–150 mmHg, ensuring a constant ow to the organs as long
as the mean arterial pressure (MAP) is maintained within this range
[34]. After premedication, the MAP value remained within the range
reported in the literature [8, 34]. It was concluded that the doses
of Medetomidine and Dexmedetomidine used in this study did not
signicantly impact perfusion levels in vital organs, and adequate
perfusion was maintained.
The heart frequency results of the study showed no signicant
difference between the Medetomidine and Dexmedetomidine
groups and were in line with the literatures [12, 13, 14, 15, 16] and
although Dexmedetomidine is twice as potent as Medetomidine,
it is argued that the effects of equivalent doses of Medetomidine
and Dexmedetomidine on the cardiovascular system are similar.
However, since the P–value was close to the 0.05 limit (P=0.078), it
was interpreted that there might be a difference between the two
groups. Although this difference was not statistically signicant, the
heart rate results in the preanesthetic period and after premedication
were lower in the Medetomidine group.
Studies have reported that Medetomidine acts more rapidly,
exhibits less vasoconstriction at the injection site, and is absorbed
more quickly than Dexmedetomidine following intramuscular
administration in dogs [35] an alpha2–adrenoceptor agonist, is a
racemic mixture of two optical stereoisomers: dexmedetomidine (the
active enantiomer. The heart rate results supported those of Bennet
et al. [35] an alpha2–adrenoceptor agonist, is a racemic mixture of
two optical stereoisomers: dexmedetomidine (the active enantiomer,
showing a more rapid decrease in heart rate in the Medetomidine
group compared to the Dexmedetomidine group. However, there
was no signicant difference observed between the two groups in
pulse rate results, contrary to the ndings of Bennetetal. [35] an
alpha2–adrenoceptor agonist, is a racemic mixture of two optical
stereoisomers: dexmedetomidine the active enantiomer. Peripheral
vasoconstriction was found to be similar in both groups. Similarly,
no statistically signicant difference was observed in SBP, DBP, and
MAP values, which are crucial indicators of hemodynamic stability,
consistent with previous literature [12, 13, 14, 15, 16]. These ndings
suggest that the use of Medetomidine or Dexmedetomidine at
equivalent doses does not confer superiority over each other based
solely on hemodynamic parameters.
CONCLUSIONS
In this study, the effects of Medetomidine and Dexmedetomidine
on hemodynamic parameters in cats were compared. In conclusion,
equivalent doses of Medetomidine and Dexmedetomidine have similar
effects on hemodynamic parameters in cats and can be safely used
interchangeably for premedication. However, if these drugs are
intended for purposes other than premedication, nociception and
other vital parameters should also be evaluated.
Ethical statement
This study was approved by the Cerrahpasa Faculty of Veterinary
Science Animal Experiments Local Ethics Board (2019/109).
Conict of interest
The authors declares that they have no conflict of interest.
Statement of Animal Rights all applicable international, national, and/or
institutional guidelines for the care and use of animals were followed.
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