Arterial Blood Pressure In Dogs Research Articles

Changes to intraocular pressure and systemic blood pressure in dogs during moderate treadmill exercise - a short communication

Physical exercise in humans induces changes in intraocular pressure, relating to the type and intensity of the workload. The purpose of the present study was to evaluate the variations in intraocular pressure and arterial blood pressure in dogs that underwent physical exercise on a treadmill. Thirty dogs were submitted to physical exercise consisting of walking (15 minutes), trotting (20 minutes), and walking (10 minutes). The intraocular pressure, blood pressure and pulse rate were recorded for each dog before starting the treadmill exercise, immediately after it ended, and after 20 minutes of passive recovery. Two-way repeated analysis of variance measurement showed the significant effect of treadmill exercise (P≤0.01) on intraocular pressure, pulse rate and diastolic blood pressure. No significant changes were observed to systolic blood pressure. Intraocular pressure and diastolic blood pressure decreased significantly during the passive recovery, and were strongly related. The pulse rate was significantly lower during the passive recovery. Although the mechanism determining the reduction in intraocular pressure during exercise remains not fully understood, our results suggest that it is strongly related to variations in arterial blood pressure.

Evaluation of the Accuracy of the Delta Life DL 1000 Oscillometric Monitor for Blood Pressure Measurement in Anesthetized Dogs of Different Weight Ranges

Background: Arterial blood pressure is one of the most commonly variables monitored during anesthetic procedures in veterinary patients. The most reliable method for measuring arterial blood pressure in dogs and cats is the direct (invasive) method. However, the oscillometric method is less complex and more practical for clinical routine in small animals. Nevertheless, oscillometric monitors present great variability in accuracy. The present study aimed to determine the accuracy of the Delta Life DL 1000 oscillometric monitor for measurement of systolic, mean and diastolic blood pressures (SAP, MAP and DAP, respectively) in anesthetized dogs of different weight ranges.Materials, Methods & Results: This study was approved by the Institutional Ethics Committee of Animal Use. Fifteen female dogs of different breeds, weighing 11.6 ± 10.0 kg and with a mean age of 48 ± 51 months were used. All animals were scheduled for elective surgery under general anesthesia in the Institution Veterinary Hospital. Dogs were anesthetized with morphine, propofol and isoflurane and had one 20 or 22 gauge catheter introduced into the dorsal pedal artery for continuous, invasive monitoring of SAP, MAP and DAP. A blood pressure cuff was positioned over the middle third of the radius and connected to Delta Life DL 1000 monitor. Oscillometric readings of SAP, MAP and DAP were registered every 5 minutes, and invasive values were simultaneously recorded. Values obtained with both methods were compared (invasive versus oscillometric) by use of the Bland Altman method to determine the bias, standard deviation of bias and 95% limits of agreement. The percentages of errors between the methods within 10 mmHg and within 20 mmHg were calculated. The results obtained were compared with the criteria from the American College of Veterinary Internal Medicine (ACVIM) for validation of indirect methods of arterial blood pressure measurement. Data were stratified into two groups according to the weight: < 10 kg (Group 1; n = 9); and ≥ 10 kg (Group 2; n = 6). In Group 1, 119 paired measurements were obtained, four of which classified as hypotension (SAP < 90 mmHg), 98 as normotension (SAP from 90 to 140mmHg) and 17 as hypertension (SAP > 140 mmHg). Bias (± SD) values in Group 1 were as follows: SAP, 5.2 ± 18.1 mmHg; MAP, -3.4 ± 17.2 mmHg; and DAP, 12.0 ± 17.5 mmHg. The percentages of errors within 10 mmHg were 40.3% for SAP; 45.4% for MAP and 28.6% for DAP. The percentages of errors within 20 mmHg were 72.3% for SAP, 84.0% for MAP and 68.1% for DAP. In Group 2, 66 paired measurements were obtained, nine of which classified as hypotension, 56 as normotension and one as hypertension. Bias (± SD) in Group 2 were as follows: SAP, 13.6 ± 14.3 mmHg; MAP, -1.1 ± 13.5 mmHg; and DAP, 8.2 ± 16.0 mmHg. The percentages of errors within 10 mmHg were 33.3% for SAP, 77.3% for MAP and 33.3% for DAP. The percentages of errors within 20 mmHg were 65.1% for SAP, 92.4% for MAP and 83.4% for DAP.Discussion: Based on the results of this study and reference criteria from the ACVIM, the Delta Life DL 1000 monitor had a poor accuracy for SAP, MAP and DAP and did not meet the criteria from the ACVIM in anesthetized dogs under 10 kg. Measurements of MAP in dogs ≥ 10 kg met the ACVIM criteria, but measurements of SAP and DAP did not. Based on the findings in this study, the DL 1000 oscillometric monitor is not recommended for blood pressure measurement in anesthetized dogs < 10 kg. In dogs ≥ 10 kg, measurements of MAP yielded acceptable values, but SAP and DAP measurements did not.

Non-invasive determination of reference arterial blood pressure indices of healthy Alsatian and Boerboel dogs

In order to evaluate and manage Boerboels and Alsatians under critical and emergency care, knowledge of ranges and causes of variability of normal arterial blood pressure (ABP) indices is desirable. The systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) of 30 healthy dogs were evaluated with human sphygmomanometer and neonatal cuff. The age, sex, breed, weight, height, weight to height ratio (WTH), of each dog was recorded. The mean and range of ABP values for Alsatians and Boerboels were similar to those of some other breeds. There were no age, breed and sex differences in ABP indices of dogs. The coefficient of variations and ranges of DAP and MAP were significantly higher than SAP measurements. In all dogs, SAP was influenced by breed and interaction of breed and sex when all confounders were controlled. The WTH and sex were found to independently influence SAP in presence of confounders. In Alsatian, WTH and sex interaction influenced all pressures in presence of confounders. The DAP was significantly influenced by heart rate and WTH in presence and absence of confounders respectively. Although age did not influence ABP in all dogs, it influenced SAP and DAP in females and Boerboel. The absence of age, sex, and breed differences in ABP of dogs may be due to multiple interactions between these factors. The human sphygmomanometer has the best precision for SAP measurements and WTH may be used as canine’s body mass index (BMI) because of its influence on ABP.Keywords: Blood pressure, dogs, breed, sex, age, oscillometry

Agreement Between Doppler and Invasive Blood Pressure Monitoring in Anesthetized Dogs Weighing

The objectives of this study were to determine if Doppler (DOP) blood pressure measurements more closely estimate either invasive systolic or invasive mean arterial blood pressures (ISAP or IMAP, respectively) in small dogs under general anesthesia and to assess the ability of DOP to detect anesthesia-related hypotension in small dogs. Blood pressure measurements (n = 203) were obtained from 10 client-owned dogs. DOP, ISAP, and IMAP were recorded simultaneously, and the data were categorized into two groups: hypotensive (ISAP <90 mm Hg) and normotensive (ISAP ≥90 mm Hg and ≤160 mm Hg). DOP overestimated ISAP and IMAP in both the normotensive and hypotensive groups. The DOP was highly specific (97%) but poorly sensitive (56%) for detecting hypotension. The smallest bias was achieved when using DOP as an estimate of systolic arterial blood pressure in both normotensive and hypotensive dogs, suggesting that DOP measures systolic arterial blood pressure in dogs <5 kg. For dogs with hypotension, DOP met all of the performance criteria for noninvasive blood pressure monitors recommended by the American College of Veterinary Internal Medicine. DOP is an acceptably accurate and highly specific means of detecting hypotension in small dogs under general anesthesia.

Evaluation of the effects of hospital visit stress on physiologic variables in dogs.

To evaluate differences in pulse rate, rectal temperature, respiratory rate, and systolic arterial blood pressure in dogs between the home and veterinary hospital environments. Prospective observational study. 30 client-owned healthy dogs. Study dogs had respiratory rate, pulse rate, rectal temperature, and systolic arterial blood pressure measured in their home environment. Dogs were then transported to the veterinary hospital, and measurements were repeated. Significant differences in blood pressure, rectal temperature, and pulse rate were observed between measurements obtained in the home and hospital environments. Mean blood pressure increased by 16% (95% confidence interval [CI], 8.8% to 24%), rectal temperature increased by < 1% (95% CI, 0.1% to 0.6%), and pulse rate increased by 11% (95% CI, 5.3% to 17.6%). The number of dogs panting in the hospital environment (19/30 [63%]) was significantly higher than the number of dogs panting in the home environment (5/30 [17%]) Results of the present study suggested that practitioners should consider stress from transportation and environmental change when canine patients have abnormalities of vital signs on initial examination, and the variables in question should be rechecked before a definitive diagnosis of medical illness is reached or extensive further workup is pursued.

Effect of body position on indirect measurement of systolic arterial blood pressure in dogs

To determine whether a difference existed in Doppler ultrasonographic measurements of systolic arterial blood pressure (SAP) in sitting versus laterally recumbent dogs and to determine the degree of variability in measurements made in each position. Diagnostic test evaluation. 51 healthy or sick adult dogs, without recent sedation or anesthesia and with an SAP ≤ 300 mm Hg. In a crossover design, SAP was measured via Doppler ultrasonography when dogs were sitting (on hind limbs with nonmeasured forelimb bearing weight) and laterally recumbent, with the cuff position at the level of the right atrium for both positions. Seven measurements were obtained per position for each dog. Mean ± SD SAP was significantly higher in the sitting (172.1 ± 33.3 mm Hg) versus recumbent (147.0 ± 24.6 mm Hg) position, and this difference was evident for 44 of 51 (86%) dogs. The mean difference in measured SAP between the 2 positions was 25.1 ± 28.5 mm Hg. Blood pressure measurements had a significantly higher repeatability in the recumbent position than in the sitting position. Blood pressure measurements in dogs were significantly affected by body position, and they were higher for most dogs when sitting rather than laterally recumbent. Blood pressure measurements in the laterally recumbent body position were less variable than in the sitting position.

Variaciones hematológicas y de presión sanguínea en perros después de una picadura de abejas

RESUMENObjetivo. El objetivo de este estudio fue determinar los cambios hematológicos y de presión arterial en perros después de una picadura cutánea de abejas. Material y métodos. Se utilizaron 10 perros adultos, a los cuales se les inoculó veneno de abeja mediante una picadura cutánea controlada. De cada animal se extrajo una muestra de sangre previa y los 15 y 300 minutos post inoculación. Se registró la presión arterial sistólica (PAS), diastólica (PAD), media (PAM) y de pulso (PP) desde 15 minutos previos hasta 45 minutos posteriores a la inoculación. Resultados. El recuento de eritrocitos, el hematocrito y la concentración de hemoglobina se redujeron a los 15 minutos post-inoculación (p&lt;0.05), retornando a valores basales al tiempo 300. El recuento de reticulocitos disminuyó al tiempo 15 en relación al tiempo 0 (p&lt;0.05), manteniéndose bajo a los 300 minutos. Se observó una disminución del recuento relativo de eosinófilos a los 300 minutos relación al tiempo 0 (p&lt;0.05). La media de la PAS a los minutos 3, 15, 30 y 39 fueron inferiores a la del minuto -15, y en la PAD, las medias de los minutos 15, 42 y 45 fueron inferiores a del minuto 9 (p&lt;0.05). A su vez, la PAM y la PP permanecieron constantes (p&gt;0.05). Conclusiones. La picadura cutánea de abejas produce un descenso transitorio del recuento de eritrocitos, hematocrito y concentración de hemoglobina, junto con una disminución en el recuento de reticulocitos y del recuento relativo de eosinófilos, sin alterar mayormente la presión sanguínea.

Pharmacological activation of KCa3.1/KCa2.3 channels produces endothelial hyperpolarization and lowers blood pressure in conscious dogs

In rodents, the endothelial KCa channels, KCa3.1 and KCa2.3, have been shown to play a crucial role in initiating endothelium-derived hyperpolarizing factor (EDHF) vasodilator responses. However, it is not known to what extent these channels are involved in blood pressure regulation in large mammals, which would also allow us to address safety issues. We therefore characterized canine endothelial KCa3.1 and KCa2.3 functions and evaluated the effect of the KCa3.1/KCa2.3 activator SKA-31 on blood pressure and heart rate in dogs. Canine endothelial KCa3.1/KCa2.3 functions were studied by patch-clamp electrophysiology and wire myography in mesenteric arteries. Systemic cardiovascular actions of acute SKA-31 administration were monitored in conscious, unstressed beagle dogs. Mesenteric endothelial cells expressed functional KCa3.1 and KCa2.3 channels that were strongly activated by SKA-31. SKA-31 hyperpolarized the endothelial membrane and doubled endothelial hyperpolarization-dependent vasodilator responses in mesenteric arteries. SKA-31 (2 mg·kg(-1), i.v.) rapidly decreased the MAP by 28 ± 6 mmHg; this response was transient (8 ± 1 s), and the initial drop was followed by a fast and pronounced increase in HR (+109 ± 7 beats min(-1)) reflecting baroreceptor activation. SKA-31 significantly augmented similar transient depressor responses elicited by ACh (20 ng·kg(-1)) and doubled the magnitude of the response over time. Activation of endothelial KCa3.1 and KCa2.3 lowers arterial blood pressure in dogs by an immediate electrical vasodilator mechanism. The results support the concept that pharmacological activation of these channels may represent a potential unique endothelium-specific antihypertensive therapy.

New insights into adenosine‐mediated myocardial protection

British Journal of Pharmacology (2005) 145, 701–702. doi:10.1038/sj.bjp.0706262

Effect of Tricycline B on the Arterial Blood Pressure in Dogs

Rajaian, H. and Kamrani, A. 1999. Effect of tricycline B on the arterial blood pressure in dogs. J. Appl. Anim. Res., 16: 201–203. The effect of tricycline B on the arterial blood pressure in dog was studied. Various doses of sodium tricycline B and control solutions were successively injected via cephalic vein and changes in systolic and diastolic blood pressures were recorded. The results indicate that low doses of sodium tricycline B increase blood pressure, but subsequent higher doses had no further effect.

Effect of tricycline B on the arterial blood pressure in dogs

Abstract Rajaian, H. and Kamrani, A. 1999. Effect of tricycline B on the arterial blood pressure in dogs. J. Appl. Anim. Res., 16: 201–203. The effect of tricycline B on the arterial blood pressure in dog was studied. Various doses of sodium tricycline B and control solutions were successively injected via cephalic vein and changes in systolic and diastolic blood pressures were recorded. The results indicate that low doses of sodium tricycline B increase blood pressure, but subsequent higher doses had no further effect.

Non-invasive measurement of arterial blood pressure in dogs: a potential indicator for the identification of stress

The reproducibility of indirect measurements of arterial pressure in dogs was assessed using the Dinamap 1846 sx oscillometric monitor and tail cuffs. Measurements on different days correlated excellently in 20 working dogs, with indistinguishable group means for systolic, diastolic and mean arterial pressure, whereas heart rates differed, though not significantly. The similarity of the means did not simply result from ‘cancelling out’ of individual variations; the rank correlation was also highly significant (P<0·01 diastolic, P<0·002 systolic). Remeasurement in the veterinary clinic, rather than ‘neutral territory’ showed significant increases in pressure but not heart rate. Anticipation of work raised systolic pressure whereas heart rate and diastolic pressure were unchanged. Exposure of a dog to a known stressor for that individual (sound) raised systolic and diastolic pressure as well as heart rate; diastolic pressure was the fastest to recover, heart rate the slowest. The data are compared with other observations on non-invasive blood pressure measurement in both dogs and humans.

Rate sensitivity of blood pressure to hypoxia

A biochemical kinetic model is used to describe changes in mean arterial blood pressure in dogs to three different rates of fall of arterial partial pressure of oxygen. The model is a linear loop with one variable rate coefficient (parametric control) which has been previously shown to characterize the rate sensitivity to presented stimuli. A three component model was identified under a least squares criterion and it showed that a unique (stimulation independent) representation can be obtained which can serve as a conceptual framework for the study of this phenomenon.

β-Blocking and Hemodynamic Effects of ASL-8052

The hemodynamic and cardiac beta-blocking effects of ASL-8052 (esmolol), an ultrashort-acting beta-blocker, were examined in pentobarbital-anesthetized dogs. The compound produced dose-dependent reductions in heart rate, left ventricular dP/dt, right ventricular contractile force, and diastolic arterial blood pressure in dogs with intact autonomic function. ASL-8052 was devoid of any hemodynamic effects in ganglion-blocked animals. Responses to isoproterenol (except for diastolic blood pressure) were blocked by ASL-8052 in qualitatively similar fashion in both groups of animals. The compound reduced the rate-pressure product and decreased diastolic coronary blood flow. The reactive hyperemic response to a 10-s occlusion of the left circumflex coronary artery was not modified by ASL-8052. Heart rate and contractile force dose-response curves to isoproterenol were equally shifted to the right in a dose-dependent, parallel fashion by constant infusion of ASL-8052. During infusion of large doses in reserpinized dogs, the compound decreased heart rate, contractility, and arterial blood pressure, while left ventricular end-diastolic pressure increased. No intrinsic sympathomimetic effect was observed. Tachycardia induced by either stimulation of the right ansa subclavia or intravenous injection of isoproterenol was blocked to an equivalent degree by ASL-8052. These data indicate that ASL-8052 produces hemodynamic effects that are characteristic of and explained by beta-adrenergic receptor blockade. However, direct cardiac depression is observed at extremely high doses.

Regional blood flow during cardiopulmonary resuscitation with abdominal counterpulsation in dogs

The addition of abdominal counterpulsation to standard cardiopulmonary resuscitation (AC-CPR) during ventricular fibrillation has been shown to improve cardiac output, oxygen uptake, and central arterial blood pressure in dogs. The present study was performed to determine the effect of AC-CPR on regional blood flow. Regional blood flow was measured with radioactively labeled microspheres during sinus rhythm and during alternate periods of AC-CPR and standard CPR (STD-CPR) in nine dogs anesthetized with pentobarbital. Blood pressures and oxygen uptake were measured continuously. As in previous studies, diastolic arterial pressure was higher (30.8%) during AC-CPR than during STD-CPR, as were cardiac output (24.5%) and oxygen uptake (37.5%). Whole brain and myocardial blood flow increased 12.0% and 22.7%, respectively, during AC-CPR. Blood flow to abdominal organs was not changed appreciably in response to abdominal compression, and postmortem examination revealed no gross trauma to the abdominal viscera. The AC-CPR technique is simple and is easily added to present basic life support procedures. In light of the improvements observed in myocardial and cerebral blood flow, AC-CPR could significantly improve the outcome of CPR attempts.

Microprocessor-based controller for pharmacodynamical applications

To design an automatic drug delivery system for the purpose of keeping the output as close as possible to a desired value, the system input-output is first represented as an autoregressive model. A minimum variance controller is then designed to solve the control problem. The implementation of the controller is performed on a microprocessor. As a specific application, the control of the mean arterial blood pressure in dogs using a vasodilator drug is presented. An automated drug deliver system is constructed; it contains a microprocessor (Motorola 6800), A/D and D/A converters. The output of the microprocessor drives a pump, which injects the drug at an appropriate rate into the blood circulation of the dog. The algorithms for the microprocessor are based on the on-line parameter estimation and optimal controller equations. The resulting closed-loop system was tested on dogs using nitroprusside as the drug which decreases the blood pressure. The tests were performed over the range of 90-170 mm Hg of the mean arterial blood pressure and over time periods of 6-10 rain. The system constructed maintains the mean arterial blood pressure within ± 10 mHg from the desired constant value. Results from typical experiments are presented and discussed.

Digital control of mean arterial blood pressure in dogs by injecting a vasodilator drug.

An automated drug administration system is presented here to control the desired decrease of the mean arterial blood pressure\((\overline {bp} )\) in dogs. The system consists of a microprocessor (6800) with A/D and D/A converters and a syringe pump, which injects the drug into the dog. For the control of the\(\overline {bp} \), the micro-processor first estimates the parameters of a discrete-time model for the open-loop system by means of the least squares algorithm. Using the resulting model, the feedback gains of an optimal controller are determined so that the\(\overline {bp} \) is maintained at the desired level. The microprocessor acts then as the controller. Its input consists of the sampled values of the actual\(\overline {bp} \), and it generates an output which is fed into the syringe pump via the D/A converter. The drug delivery system designed was tested using sodium nitroprusside as a vasodilator drug in five dogs. The controller parameters were computed for each test run. The closed-loop system was tested in the range 90–170 mm Hg of the\(\overline {bp} \) over a time period of 6–10 min. The desired mean arterial blood pressure value was maintained within ±10 mm Hg over the test period.

Automatic continuous-time blood pressure control in dogs by means of hypotensive drug injection.

An automated drug administration system is proposed to control the decrease in the mean arterial blood pressure of dogs. It is accomplished by identifying a model for the open loop system consisting of a syringe pump and a dog. A linear feedback controller is then determined by solving an inverse optimum control problem. The chosen controller is optimal relative to a quadratic critexion. The controller is designed so that the mean arterial blood pressure is maintained at a desired level.

Plasma vasopressin in blood pressure homeostasis and in experimental renal hypertension.

The role of vasopressin in blood pressure control and in the pathogenesis of one-kidney Goldblatt hypertension was investigated in the conscious dog. Intravenous infusion of synthetic arginine vasopressin to elevate plasma levels approximately fivefold to 31 pg/ml caused bradycardia in normal dogs, together with suppression of plasma renin activity and angiotensin II. This plasma level of vasopressin also caused elevation of mean arterial blood pressure in dogs with pharmacological total autonomic blockade. A similar degree of elevation of plasma vasopressin concentration was observed following mild nonhypotensive hemorrhage; more severe hemorrhage resulted in an approximate 100-fold increase in plasma vasopressin levels. Severe renal artery constriction in unilaterally nephrectomized dogs caused a marked rise in mean arterial blood pressure, but only a doubling of plasma vasopressin concentration. A suppressor infusion of vasopressin did not potentiate the pressor response to infused angiotensin II. It is concluded that vasopressin may play a role in normal cardiovascular homeostatic responses, but it is unlikely to have a significant direct vasoconstrictor role in the pathogenesis of this form of experimental renal hypertension.

The Role of Vasopressin in Blood Pressure Control and in Experimental Hypertension

1. The role of vasopressin in blood pressure control and in the pathogenesis of one-kidney Goldblatt hypertension in the conscious dog was investigated. 2. Infusion of synthetic arginine vasopressin to elevate plasma levels approximately five-fold caused bradycardia in normal dogs and increase in mean arterial blood pressure in dogs with pharmacological autonomic blockade. 3. A similar degree of elevation of plasma vasopressin concentration was observed after mild non-hypotensive haemorrhage. 4. Renal artery constriction in unilaterally-nephrectomized dogs caused a rise in plasma renin activity and only a doubling of plasma vasopressin concentration, but a marked rise in mean arterial blood pressure. 5. Vasopressin may play a role in normal cardiovascular homeostatic responses, but its role in the pathogenesis of this form of hypertension is unlikely to be significant.