Topic:Blood Pressure
Blood pressure in horses refers to the force exerted by circulating blood on the walls of the blood vessels. It is a vital physiological parameter that can provide insights into the cardiovascular health of equines. Blood pressure is influenced by various factors, including heart rate, blood volume, and vascular resistance. In horses, blood pressure measurements can be used to assess cardiac function, detect circulatory abnormalities, and monitor the effects of anesthesia or medications. This page compiles peer-reviewed research studies and scholarly articles that explore the methods of measuring blood pressure in horses, the factors affecting it, and its implications for equine health management.
The relationship of muscle perfusion and metabolism with cardiovascular variables before and after detomidine injection during propofol-ketamine anaesthesia in horses. To study in horses (1) the relationship between cardiovascular variables and muscle perfusion during propofol-ketamine anaesthesia, (2) the physiological effects of a single intravenous (IV) detomidine injection, (3) the metabolic response of muscle to anaesthesia, and (4) the effects of propofol-ketamine infusion on respiratory function. Methods: Prospective experimental study. Methods: Seven standardbred trotters, 5-12 years old, 416-581 kg. Methods: Anaesthesia was induced with intravenous (IV) guaifenesin and propofol (2 mg kg) and maintained with a continuous IV infusion of propofol (0.15...
Aerosolized salbutamol (albuterol) improves PaO2 in hypoxaemic anaesthetized horses – a prospective clinical trial in 81 horses. To compare the arterial pH and blood gas values, heart rate and mean arterial blood pressure, in hypoxaemic anaesthetized horses, before and after treatment, with a salbutamol (albuterol) aerosol. Methods: Eighty-one client-owned horses weighing between 114 and 925 kg. Fifty-seven underwent emergency abdominal surgery and 24 were anaesthetized for elective procedures. Methods: Pre-anaesthetic medication included xylazine, detomidine, butorphanol and morphine, alone or in various combinations. Induction of anaesthesia was achieved with guaifenesin and ketamine, diazepam and ketamine, or guaifen...
Anaesthesia in horses using halothane and intravenous ketamine-guaiphenesin: a clinical study. The aim of this study was to define and evaluate a combined inhalation-intravenous anaesthetic protocol for use in equine anaesthesia. Methods: Prospective, randomized clinical trial. Methods: Twenty-eight horses (body mass 522 ± 82; 330-700 kg [mean ± SD; range]) with a mean age of 6 ± 4 years (range: 2-18 years) presented to the university hospital for various surgical procedures requiring general anaesthesia. Methods: Animals were randomly allocated to one of two treatment groups. Anaesthesia was maintained in 14 horses with halothane alone (H group). The mean end-tidal halothane concent...
The cardiopulmonary effects of severe blood loss in anesthetized horses. To characterize the acute cardiopulmonary effects of severe hemorrhage in anesthetized horses. Methods: Prospective experimental study. Methods: Three geldings and six mares, aged 14.4 ± 2.7 years, weighing 486 ± 41 kg (range: 425-550 kg). Methods: Horses were anesthetized using xylazine, guaifenesin, ketamine and halothane or isoflurane. Cardiovascular variables, hematocrit, total solids, capillary refill time (CRT) and color of mucous membranes were measured as blood was collected from the carotid artery into sterile plastic bags. Arterial blood gas analysis was also performed. Results: Th...
Blood pressure in Warmblood horses before and during a euglycemic-hyperinsulinemic clamp. Insulin resistance (IR) in humans is related to hypertension and impaired vasodilation. Insulin administration has been shown to lower blood pressure both in insulin resistant as well as in insulin sensitive individuals. The aim of the study was to investigate the association between insulin sensitivity and alterations in blood pressure in healthy horses before and after a euglycemic-hyperinsulinemic clamp (EHC). A 3-h EHC was performed in 13 healthy horses (11 mares, 2 geldings). Blood samples for measurement of plasma glucose and insulin were collected before the start of the EHC, every 10 ...
Effect of Regional Intravenous Limb Perfusate Volume on Synovial Fluid Concentration of Amikacin and Local Venous Blood Pressure in the Horse. To determine the effect of volume of amikacin perfusate for intravenous regional limb perfusion (IVRLP) via the cephalic vein in standing, sedated horses on (1) amikacin concentrations in the synovial fluid of the radiocarpal joint (RCJ) and distal interphalangeal joint (DIPJ) and, (2) amikacin concentration in the systemic circulation, and (3) regional intravenous pressure. Methods: Randomized cross-over design. Methods: Six adult horses. Methods: Each horse received IVRLP using 4 perfusate volumes (10, 30, 60 & 120 ml) in random order, after a minimum of 1 week washout. After application of ...
Attenuation of the blood pressure response to exogenous angiotensin I after oral administration of benazepril to healthy adult horses. Benazepril has been shown to inhibit circulating angiotensin-converting enzyme (ACE) activity in horses but the optimal dosage is unknown. Objective: To determine the lowest tested dose of benazepril that results in ≥75% attenuation in the response of arterial blood pressure (BP) to exogenous angiotensin I (ANG-I) administration. Methods: Prospective experimental study. Methods: A total of 5 healthy horses were instrumented for the direct measurement of BP. Each horse received 4 intragastric doses of benazepril (0.5, 1, 2 and 4 mg/kg bwt) with a washout period of 7 days between doses. Prior ...
Accuracy and Precision of Noninvasive Blood Pressure in Normo-, Hyper-, and Hypotensive Standing and Anesthetized Adult Horses. Blood pressure is relevant to the diagnosis and management of many medical, cardiovascular and critical diseases. The accuracy of many commonly used noninvasive blood pressure (NIBP) monitors and the accuracy of NIBP measurements in hypo- and hypertensive standing horses has not been determined. Objective: The objective of this study was to investigate the accuracy of an oscillometric BP monitor in standing horses before and during pharmacologically induced hyper- and hypotension and to compare results in standing and anesthetized horses. Methods: Eight standing mares from a research herd (SG)...
Effects of positive end-expiratory pressure titration on intestinal oxygenation and perfusion in isoflurane anaesthetised horses. High airway pressures, necessary to keep equine lungs open, can have a detrimental impact on central and peripheral perfusion. Objective: The aim of this study was to assess the effects of stepwise increasing airway pressure recruitment on central and intestinal perfusion and oxygenation during isoflurane anaesthesia in horses. Methods: In vivo experimental study. Methods: Ten anaesthetised horses were ventilated using intermittent positive pressure ventilation immediately after induction. After 90 min, end-expiratory pressure (PEEP) was increased by steps of 5 cmH2 O every 10 min up to a PEEP...
The Efficacy of Equine-Assisted Activities and Therapies on Improving Physical Function. To summarize the physical benefits of therapeutic horseback riding and hippotherapy and suggest directions for future research. Methods: Review of databases for peer-reviewed articles related to equine-assisted activities and therapies. Databases included MEDLINE via EBSCO, Web of Science, PubMed, Google Scholar, and Academic Search Complete. Articles were limited to those with full-text access published in English since 1987. Results: Acute and residual improvements in physical benefits, such as gross motor function (e.g., walking, running, jumping), spasticity, muscle symmetry, posture, bala...
Pharmacokinetics and pharmacodynamics of ramipril and ramiprilat after intravenous and oral doses of ramipril in healthy horses. The pharmacokinetics and pharmacodynamics (PK/PD) of the angiotensin-converting enzyme inhibitor (ACEI) ramiprilat after intravenous (IV) and oral (PO) administration of ramipril have not been evaluated in horses. This study was designed to establish PK profiles for ramipril and ramiprilat as well as to determine the effects of ramiprilat on serum angiotensin converting enzyme (ACE) and to select the most appropriate ramipril dose that suppresses ACE activity. Six healthy horses in a cross-over design received IV ramipril 0.050 mg/kg, PO at a dose of 0 (placebo), and 0.050, 0.10, 0.20, 0.40 ...
Modulation of acute transient exercise-induced hypertension after oral administration of four angiotensin-converting enzyme inhibitors in normotensive horses. Changes in blood pressure (BP) during acute hypertension in response to angiotensin-converting enzyme inhibitors (ACEIs) have not been investigated in normotensive horses. In this study, six healthy horses were subjected to five trials, consisting in a treadmill exercise workload of 8 m/s for 1 min, 2 h after oral administration (PO) of placebo (0 mg/kg), enalapril (2.0 mg/kg), quinapril (1.0 mg/kg), ramipril (0.2 mg/kg) or benazepril (0.5 mg/kg). Serum angiotensin converting enzyme (ACE) activity was measured and systolic (SBP) and diastolic (DBP) blood pressures were recorded...
Accuracy and precision of oscillometric blood pressure in standing conscious horses. Arterial blood pressure (BP) is a relevant clinical parameter that can be measured in standing conscious horses to assess tissue perfusion or pain. However, there are no validated oscillometric noninvasive blood pressure (NIBP) devices for use in horses. Methods: Seven healthy horses from a teaching and research herd. Objective: To evaluate the accuracy and precision of systolic arterial pressure (SAP), diastolic arterial pressure (DAP), and mean arterial pressure (MAP) in conscious horses obtained with an oscillometric NIBP device when compared to invasively measured arterial BP. Methods: An ...
The cardiovascular status of isoflurane-anaesthetized horses with and without dexmedetomidine constant rate infusion evaluated at equivalent depths of anaesthesia. To compare cardiac index and oxygen extraction at equivalent depths of anaesthesia between isoflurane-anaesthetized horses and horses anesthetized with isoflurane and dexmedetomidine CRI. Methods: Sequential, blinded, randomized, balanced, crossover study. Methods: Eight horses weighing a mean ± standard deviation of 478 ± 58 kg. Methods: Horses were premedicated with 0.03 mg kg(-1) acepromazine intramuscularly (IM) and 8 μg kg(-1) dexmedetomidine intravenously (IV). Anaesthesia was induced with 2.5 mg kg(-1) ketamine and 0.1 mg kg(-1) midazolam IV and maintained with isofluran...
Electrophysiologic Study of a Method of Euthanasia Using Intrathecal Lidocaine Hydrochloride Administered during Intravenous Anesthesia in Horses. An intravenous (IV) overdose of pentobarbital sodium is the most commonly used method of euthanasia in veterinary medicine. However, this compound is not available in many countries or rural areas resulting in usage of alternative methods such as intrathecal lidocaine administration after IV anesthesia. Its safety and efficacy as a method of euthanasia have not been investigated in the horse. Objective: To investigate changes in mean arterial blood pressure and electrical activity of the cerebral cortex, brainstem, and heart during intrathecal administration of lidocaine. Our hypothesis was th...
Comparison of invasive and noninvasive blood pressure measurements in anaesthetized horses using the Surgivet V9203. To determine the bias and precision of noninvasive versus invasive blood pressure measurements obtained using the Surgivet V9203 in anaesthetized horses; to compare these with the current American College of Veterinary Internal Medicine Hypertension Consensus Panel (AHCP) and Veterinary Blood Pressure Society (VBPS) recommendations; and to investigate whether noninvasive blood pressure monitoring could be a clinically useful alternative to invasive blood pressure monitoring in anaesthetized horses. Methods: Prospective clinical study in a university teaching hospital. Methods: Forty-three hors...
Temporal and concentration effects of isoflurane anaesthesia on intestinal tissue oxygenation and perfusion in horses. The aim of this study was to assess the effect of duration of anaesthesia and concentration of isoflurane on global perfusion as well as intestinal microperfusion and oxygenation. Nine Warmblood horses were premedicated with xylazine; anaesthesia was induced with midazolam and ketamine, and maintained with isoflurane. Horses were ventilated to normocapnia. During 7 h of anaesthesia, mean arterial blood pressures (MAP), heart rate, central venous pressure, pulmonary artery pressure, expiratory isoflurane concentration (ETIso) and cardiac output using lithium dilution were measured; cardiac in...
Effects of a constant rate infusion of medetomidine-propofol on isoflurane minimum alveolar concentrations in horses. The aim of this investigation was to determine the isoflurane-sparing effect and impact on arterial blood pressure and anaesthetic recovery of a constant rate infusion of medetomidine-propofol in horses. In a prospective, crossover, randomised study, six healthy horses (mean ± SD age, 13.7 ± 7.7 years; weight, 433 ± 51 kg) were anaesthetised twice with isoflurane and were randomly assigned to receive one of two treatments on each occasion, at least 2 weeks apart. The first treatment was saline (CTL group) and the second a medetomidine-propofol infusion (MP group; 1.25 µg/kg...
Comparison of respiratory function during TIVA (romifidine, ketamine, midazolam) and isoflurane anaesthesia in spontaneously breathing ponies Part I: blood gas analysis and cardiorespiratory variables. To compare pulmonary function and gas exchange in ponies during maintenance of anaesthesia with isoflurane or by a total intravenous anaesthesia (TIVA) technique. Methods: Experimental, cross-over study. Methods: Six healthy ponies weighing mean 286 (range 233-388) ± SD 61 kg, age 13 (9-16) ± 3 years. Methods: The ponies were anaesthetized twice, a minimum of two weeks apart. Following sedation with romifidine [80 μg kg(-1) intravenously (IV)], anaesthesia was induced IV with midazolam (0.06 mg kg(-1)) and ketamine (2.5 mg kg(-1), then maintained either with inhaled isoflurane (Fe'Iso = 1.1...
Agreement of high definition oscillometry with direct arterial blood pressure measurement at different blood pressure ranges in horses under general anaesthesia. To determine the agreement of high definition oscillometry (HDO) with direct arterial blood pressure measurements in normotensive, hypotensive and hypertensive horses during general anaesthesia. Methods: Experimental study. Methods: Seven healthy warmblood horses, aged 3-11 years, weighing 470-565 kg. Methods: Measurements from a HDO device with the cuff placed around the base of the tail were compared with pressures measured invasively from the facial artery. High blood pressures were induced by intravenous (IV) administration of dobutamine (5 μg kg(-1) minute(-1)) over ten minutes followed ...
Cardiopulmonary effects of dexmedetomidine and ketamine infusions with either propofol infusion or isoflurane for anesthesia in horses. To examine the cardiopulmonary effects of two anesthetic protocols for dorsally recumbent horses undergoing carpal arthroscopy. Methods: Prospective, randomized, crossover study. Methods: Six horses weighing 488.3 ± 29.1 kg. Methods: Horses were sedated with intravenous (IV) xylazine and pulmonary artery balloon and right atrial catheters inserted. More xylazine was administered prior to anesthetic induction with ketamine and propofol IV. Anesthesia was maintained for 60 minutes (or until surgery was complete) using either propofol IV infusion or isoflurane to effect. All horses were admi...
Effects of meloxicam and phenylbutazone on renal responses to furosemide, dobutamine, and exercise in horses. To compare the effects of 2 NSAIDs (phenylbutazone and meloxicam) on renal function in horses. Methods: 9 Thoroughbred or Standardbred mares (mean ± SD age, 5.22 ± 1.09 years [range, 2 to 12 years]; mean body weight, 470 ± 25 kg [range, 442 to 510 kg]). Methods: A randomized blinded placebo-controlled crossover study was conducted to examine the effects of treatment with phenylbutazone, meloxicam, or a placebo (control solution) on renal responses to the administration of furosemide, dobutamine, and exercise (15 minutes at 60% of maximum heart rate). Renal function was assessed by use of bi...
Pharmacokinetics and pharmacodynamics of enalapril and its active metabolite, enalaprilat, at four different doses in healthy horses. Pharmacokinetic and pharmacodynamic of IV enalapril at 0.50 mg/kg, PO placebo and PO enalapril at three different doses (0.50, 1.00 and 2.00 mg/kg) were analyzed in 7 healthy horses. Serum concentrations of enalapril and enalaprilat were determined for pharmacokinetic analysis. Angiotensin-converting enzyme (ACE) activity, serum ureic nitrogen (SUN), creatinine and electrolytes were measured, and blood pressure was monitored for pharmacodynamic analysis. The elimination half-lives of enalapril and enalaprilat were 0.67 and 2.76 h respectively after IV enalapril. Enalapril concentrations ...
Influence of ketamine or xylazine supplementation on isoflurane anaesthetized horses–a controlled clinical trial. To determine the influence of ketamine or xylazine constant rate infusions on isoflurane requirements, cardiovascular parameters and quality of anaesthesia in horses undergoing elective surgery. Methods: Prospective, matched paired clinical trial. Methods: Fifty four adult Warmblood horses. Methods: After premedication with acepromazine, xylazine and butorphanol, anaesthesia was induced with ketamine-midazolam and maintained with isoflurane alone (I), isoflurane with either 1 mg kg(-1) hour(-1) ketamine (IK) or same dose of xylazine (IX). End tidal concentration of isoflurane (Fe'Iso) was ...
Recovery from desflurane anesthesia in horses with and without post-anesthetic xylazine. The objective of this study was to compare recovery from desflurane anesthesia in horses with or without post-anesthetic xylazine. Six adult horses were anesthetized on 2 occasions, 14 d apart using a prospective, randomized crossover design. Horses were sedated with xylazine, induced to lateral recumbency with ketamine and diazepam, and anesthesia was maintained with desflurane. One of 2 treatments was administered intravenously at the end of anesthesia: xylazine [0.2 mg/kg body weight (BW)] or an equivalent volume of saline. Recovery parameters were recorded and assessed by 2 blinded observe...
Effect of body position on intra-abdominal pressures and abdominal perfusion pressures measured at three sites in horses anesthetized with short-term total intravenous anesthesia. To assess effects of body position on direct measurements of intra-abdominal pressure (IAP) and abdominal perfusion pressure (APP) in horses anesthetized with total intravenous anesthesia (TIVA). Methods: 9 healthy adult horses. Methods: Instrumentation in unsedated standing horses involved insertion of an arterial catheter for blood pressure measurements and 3 intraperitoneal cannulas (left flank, right flank, and ventral abdomen) for IAP measurements. Baseline values were measured for heart rate, respiratory rate, systolic arterial blood pressure, mean arterial blood pressure (MAP), diastoli...
[Noninvasive blood pressure measurement using high definition oscillometry in horses with heart diseases]. This study evaluated a device for blood pressure measurement using high definition oscillometry (HDO) for its acceptability and practicability in the horse. Furthermore, we evaluated whether this device can determine differences in blood pressure between healthy horses and horses with heart diseases and between different measurement times. Methods: The study population consisted of 60 horses (aged 4-31 years). All horses underwent clinical examination, conventional echocardiography (including cardiac output measurement at the pulmonary artery), repeated noninvasive blood pressure measurement a...
Effects of dexmedetomidine and xylazine on cardiovascular function during total intravenous anaesthesia with midazolam and ketamine and recovery quality and duration in horses. To compare cardiovascular effects and recovery quality and duration of total intravenous anaesthesia (TIVA) with xylazine-ketamine-midazolam or dexmedetomidine-ketamine-midazolam. Methods: Prospective, randomized experimental cross-over trial. Methods: Eight adult warmblood horses. Methods: After sedation with acepromazine and either xylazine [0.5 mg kg(-1) , intravenously (IV)] or dexmedetomidine (3.5 μg kg(-1) IV) anaesthesia was induced with ketamine and midazolam and maintained with a constant rate infusion (CRI) of xylazine (1 mg kg(-1) hour(-1) ) [XKM] or dexmedetomidine (7 μg...
Cardiorespiratory and antinociceptive effects of two different doses of lidocaine administered to horses during a constant intravenous infusion of xylazine and ketamine. This study investigated the antinociceptive effects of a constant rate infusion (CRI) of lidocaine during xylazine and ketamine anesthesia in horses and aimed to correlate these effects with cardiorespiratory variables, bispectral index (BIS) and plasma lidocaine concentrations. Six adult crossbred mares weighing 320-400 kg were anesthetized on three different occasions. Sedation was performed with xylazine (0.75 mg/kg IV) and anesthetic induction with guaifenesin (75 mg/kg IV) and ketamine (2 mg/kg IV). Anesthesia was maintained with 37.5 μg/kg/min of xylazine and 87.5 μg/kg/min of ketamine...
Pharmacodynamic evaluation of 4 angiotensin-converting enzyme inhibitors in healthy adult horses. Angiotensin-converting enzyme (ACE) inhibitors are used in horses with cardiovascular disorders despite the paucity of available data regarding their efficacy. Objective: The degree of serum ACE inhibition varies considerably between drugs. Methods: Eight healthy adult horses. Methods: Randomized prospective study. Horses were fasted overnight prior to receiving one of 4 ACE inhibitors intragastrically, administered at one of 2 dosages, using a randomized Latin square design (benazepril: 0.5 and 0.25 mg/kg; ramipril: 0.3 and 0.1 mg/kg; quinapril: 0.25 and 0.125 mg/kg; perindopril: 0.1 and 0.05...