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.
Comparison of various types of inert gas components on efficacy of an alveolar recruitment maneuver in dorsally recumbent anesthetized horses. To assess effects of nitrogen and helium on efficacy of an alveolar recruitment maneuver (ARM) for improving pulmonary mechanics and oxygen exchange in anesthetized horses. Methods: 6 healthy adult horses. Methods: Horses were anesthetized twice in a randomized crossover study. Isoflurane-anesthetized horses in dorsal recumbency were ventilated with 30% oxygen and 70% nitrogen (treatment N) or heliox (30% oxygen and 70% helium; treatment H) as carrier gas. After 60 minutes, an ARM was performed. Optimal positive end-expiratory pressure was identified and maintained for 120 minutes. Throughout ...
The effect of insulin infusion on heart rate and systemic blood pressure in horses with equine metabolic syndrome. There is little evidence that horses with equine metabolic syndrome (EMS) have higher resting blood pressures than horses with normal insulin sensitivity. However, there are indications that EMS horses have an altered dynamic response to the cardiovascular effects of insulin. Objective: To examine heart rate and the systemic blood pressure response in EMS and control horses during insulin infusion. Methods: Cross-sectional study. Methods: Horses were examined with an oral sugar test (OST) and a euglycaemic hyperinsulinaemic clamp (EHC). Based on the results from the OST, the horses were classi...
Effects of vatinoxan on cardiorespiratory function and gastrointestinal motility during constant-rate medetomidine infusion in standing horses. Medetomidine suppresses cardiovascular function and reduces gastrointestinal motility in horses mainly through peripheral α -adrenoceptors. Vatinoxan, a peripheral α -antagonist, has been shown experimentally to alleviate the adverse effects of some α -agonists in horses. However, vatinoxan has not been investigated during constant-rate infusion (CRI) of medetomidine in standing horses. Objective: To evaluate effects of vatinoxan on cardiovascular function, gastrointestinal motility and on sedation level during CRI of medetomidine. Methods: Experimental, randomised, blinded, cross-over stud...
Examination of Horses with Cardiac Disease. Despite advances, increased convenience, and availability of echocardiography and other diagnostic techniques in equine cardiology, a comprehensive history and clinical examination still forms the essential first step in any cardiac evaluation. This article summarizes the approach to the cardiac examination at rest, highlighting key areas for the clinician to assess, and stressing the importance of context for assessing the significance of any abnormalities detected. Ancillary techniques, such as blood pressure measurement and the laboratory assessment of cardiac disease in the horse, are also...
Evaluation of Sevoflurane Anesthesia in Donkeys (Equus asinus) Premedicated With Xylazine and Induced With Thiopental. Sevoflurane is a volatile anesthetic agent that has become popular in the field of large animal anesthesia. The aim of this study was to evaluate the use of sevoflurane in adult healthy donkeys. Six male, adult, healthy donkeys were premedicated with xylazine (1Â mg/kg IV), induced with thiopental (5Â mg/kg IV), and then maintained for 90Â minutes with sevoflurane in 100% oxygen at a flow rate of 6Â L/min with spontaneous breathing. Rectal temperature (RT), respiratory rate, heart rate (HR), oxygen hemoglobin saturation (OHS), and mean arterial blood pressure (MBP) were measured before and 20Â...
Subtourniquet pressures generated by application of wide-rubber tourniquets in standing, sedated horses. To determine the influence of location and movement on subtourniquet pressure (STP) generated by application of a wide-rubber tourniquet (WRT) on equine limbs. Methods: Randomized experimental cross-over design. Methods: Six standing, sedated horses. Methods: Horses were sedated with detomidine hydrochloride (0.2 μg/kg IV), and 4 investigators applied WRTs to the antebrachium (AB), gaskin (GK), and midmetacarpus (MC) of each horse in a predetermined, randomized order. Subtourniquet pressure was consequently measured at 10-minute intervals (T0, T10, T20, T30) for 30 minutes. Indirect systo...
Pharmacokinetic and pharmacodynamic properties of orally administered torsemide in healthy horses. Diuretic treatment is the mainstay for management of congestive heart failure in horses, and its use has been restricted to injectable medications because no currently data supports the use of PO administered loop diuretics. Objective: To determine the pharmacokinetic and pharmacodynamic properties of PO administered torsemide and, determine if PO administered torsemide, could be used as an alternative to injectable diuretics in the horse. Methods: Six healthy adult mares. Methods: A 2-phase, prospective study, that consisted of pharmacokinetic profiling of a single dose (6 mg/kg PO) and pharm...
Comparison of desflurane and propofol at equipotent doses in combination with a constant rate infusion of dexmedetomidine on global and peripheral perfusion and oxygenation in horses. OBJECTIVE To determine global and peripheral perfusion and oxygenation during anesthesia with equipotent doses of desflurane and propofol combined with a constant rate infusion of dexmedetomidine in horses. ANIMALS 6 warmblood horses. PROCEDURES Horses were premedicated with dexmedetomidine (3.5 μg•kg, IV). Anesthesia was induced with propofol or ketamine and maintained with desflurane or propofol (complete crossover design) combined with a constant rate infusion of dexmedetomidine (7 μg•kg •h). Microperfusion and oxygenation of the rectal, oral, and esophageal mucosa were measured bef...
Effects of MK-467 hydrochloride and hyoscine butylbromide on cardiorespiratory and gastrointestinal changes induced by detomidine hydrochloride in horses. OBJECTIVE To compare the effects of MK-467 and hyoscine butylbromide on detomidine hydrochloride-induced cardiorespiratory and gastrointestinal changes in horses. ANIMALS 6 healthy adult horses. PROCEDURES Horses received detomidine hydrochloride (20 μg/kg, IV), followed 10 minutes later by MK-467 hydrochloride (150 μg/kg; DET-MK), hyoscine butylbromide (0.2 mg/kg; DET-HYO), or saline (0.9% NaCl) solution (DET-S), IV, in a Latin square design. Heart rate, respiratory rate, rectal temperature, arterial and venous blood pressures, and cardiac output were measured; blood gases and arterial plas...
Effects of controlled hypoxemia or hypovolemia on global and intestinal oxygenation and perfusion in isoflurane anesthetized horses receiving an alpha-2-agonist infusion. Aim of this prospective experimental study was to assess effects of systemic hypoxemia and hypovolemia on global and gastrointestinal oxygenation and perfusion in anesthetized horses. Therefore, we anesthetized twelve systemically healthy warmblood horses using either xylazine or dexmedetomidine for premedication and midazolam and ketamine for induction. Anesthesia was maintained using isoflurane in oxygen with either xylazine or dexmedetomidine and horses were ventilated to normocapnia. During part A arterial oxygen saturation (SaO) was reduced by reducing inspiratory oxygen fraction in steps...
Xylazine infusion in isoflurane-anesthetized and ventilated healthy horses: Effects on cardiovascular parameters and intestinal perfusion. To investigate the effects of a xylazine infusion during isoflurane anesthesia on global perfusion parameters and gastrointestinal oxygenation and microperfusion, 8 adult warmblood horses were sedated with xylazine and anesthesia induced with midazolam and ketamine. Horses were mechanically ventilated during anesthesia. After 3 h of stable isoflurane anesthesia (FIso 1.3 Vol %), a xylazine infusion with 1 mg/kg body weight (BW) per hour was started for 1 h and then stopped. Before, during, and after xylazine infusion, heart rate (HR), arterial blood pressure (MAP), cardiac output (CO), central...
Anesthetic management with sevoflurane combined with alfaxalone-medetomidine constant rate infusion in a Thoroughbred racehorse undergoing a long-time orthopedic surgery. A three-year old Thoroughbred racehorse was anesthetized with sevoflurane and oxygen inhalation anesthesia combined with constant rate infusion (CRI) of alfaxalone-medetomidine for internal fixation of a third metacarpal bone fracture. After premedication with intravenous (IV) injections of medetomidine (6.0 µg/kg IV), butorphanol (25 µg/kg IV), and midazolam (20 µg/kg IV), anesthesia was induced with 5% guaifenesin (500 ml/head IV) followed immediately by alfaxalone (1.0 mg/kg IV). Anesthesia was maintained with sevoflurane and CRIs of alfaxalone (1.0 mg/kg/hr) and medetomidine (3.0 µg/kg...
Effect of dexmedetomidine and xylazine followed by MK-467 on gastrointestinal microperfusion in anaesthetized horses. To compare the effects of MK-467 during isoflurane anaesthesia combined with xylazine or dexmedetomidine on global and gastrointestinal perfusion parameters. Methods: Prospective, randomized experimental trial. Methods: A total of 15 warmblood horses. Methods: Horses were divided into two groups for administration of either dexmedetomidine (D) or xylazine (X) for premedication (D: 3.5 μg kg; X: 0.5 mg kg) and as constant rate infusion during isoflurane anaesthesia (D: 7 μg kg hour; X: 1 mg kg hour). During anaesthesia, heart rate, mean arterial blood pressure (MAP), systemic vascular resista...
Effects of dobutamine, dopamine, phenylephrine and noradrenaline on systemic haemodynamics and intestinal perfusion in isoflurane anaesthetised horses. In the horse, effects of cardiovascular-active drugs on local perfusion of the gastrointestinal tract are poorly understood. Objective: To determine the effect of drugs commonly used to support blood pressure, on local intestinal blood flow and tissue oxygenation under isoflurane anaesthesia. Methods: In vivo randomised crossover experiment. Methods: Ten horses were anaesthetised with isoflurane. After 90 min of equilibration three doses (μg/kg bwt/min) of dobutamine (DOB 0.5/1/3), dopamine (DA 1/2/5), noradrenaline (NA 0.1/0.2/0.5) and phenylephrine (PHE 0.5/1/3) were infused for 15 min, in ...
Right ventricular function during pharmacological and exercise stress testing in horses. The disproportionate rise of pulmonary artery pressure compared to systemic blood pressure during exercise can lead to detrimental right ventricular remodelling in endurance athletes. Horses may act as an extreme model of these athletic cardiovascular adaptations, as they show a three fold increase in pulmonary pressures during exercise. Right ventricular function was examined in ten healthy horses using post-exercise and pharmacological stress echocardiography in a randomised cross-over design. Exercise testing was performed on a treadmill while pharmacological testing was performed using an ...
Clinical comparison of dexmedetomidine and medetomidine for isoflurane balanced anaesthesia in horses. To compare the effects of two balanced anaesthetic protocols (isoflurane-dexmedetomidine versus medetomidine) on sedation, cardiopulmonary function and recovery in horses. Methods: Prospective, blinded, randomized clinical study. Methods: Sixty healthy adult warm blood horses undergoing elective surgery. Methods: Thirty horses each were sedated with dexmedetomidine 3.5 μg kg (group DEX) or medetomidine 7 μg kg (group MED) intravenously. After assessing and supplementing sedation if necessary, anaesthesia was induced with ketamine/diazepam and maintained with isoflurane in oxygen/air and ...
Cardiovascular findings in ponies with equine metabolic syndrome. OBJECTIVE To determine whether hypertension, high sympathetic tone, resting and exercising arrhythmias, and echocardiographic changes consistent with hypertensive cardiomyopathy were associated with equine metabolic syndrome (EMS) in ponies. DESIGN Prospective case-control study. ANIMALS 19 privately owned ponies with a diagnosis of EMS (history of laminitis, body condition score ≥ 7/9, cresty neck score ≥ 3/5, and abnormal oral sugar test result; cases) and 20 healthy control ponies. PROCEDURES Heart rate (HR), noninvasively measured arterial blood pressure (BP), markers of autonomic tone...
Pharmacokinetic/pharmacodynamic modeling of benazepril and benazeprilat after administration of intravenous and oral doses of benazepril in healthy horses. Pharmacokinetic and pharmacodynamic (PK/PD) properties of the angiotensin-converting enzyme inhibitor (ACEI) benazeprilat have not been evaluated in horses. This study was designed to establish PK profiles for benazepril and benazeprilat after intravenous (IV) and oral (PO) administration of benazepril using a PK/PD model. This study also aims to determine the effects of benazeprilat on serum angiotensin converting enzyme (ACE), selecting the most appropriate dose that suppresses ACE activity. Six healthy horses in a crossover design received IV benazepril at 0.50mg/kg and PO at doses 0 (place...
Comparison of the effects of an intravenous lidocaine infusion combined with 1% isoflurane versus 2% isoflurane alone on selected cardiovascular variables and recovery characteristics during equine general anaesthesia. To compare the effects of a lidocaine constant rate infusion (CRI) combined with 1% isoflurane versus those of 2% isoflurane alone on cardiovascular variables in anaesthetized horses, and to estimate the sample size required to detect a difference in recovery quality. Methods: Prospective, randomized, blinded, crossover study. Methods: Twelve healthy experimental horses. Methods: Horses were anaesthetized twice using an intravenous (IV) administration of acepromazine, romifidine, diazepam and ketamine. Horses were placed in dorsal recumbency and ventilated mechanically. During the first 10 min...
The effect of anesthetic drug choice on accuracy of high-definition oscillometry in laterally recumbent horses. To determine the accuracy of high-definition oscillometry (HDO) for arterial pressure measurement during injectable or inhalation anesthesia in horses. Methods: Prospective, clinical study. Methods: Twenty-four horses anesthetized for procedures requiring lateral recumbency. Methods: Horses were premedicated with xylazine, and anesthesia induced with diazepam-ketamine. Anesthesia was maintained with xylazine-ketamine-guaifenesin combination [TripleDrip (TD; n = 12) or isoflurane (ISO; n = 12)]. HDO was used to obtain systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, and he...
Comparison of arterial blood pressure measurements obtained invasively or oscillometrically using a Datex S/5 Compact monitor in anaesthetised adult horses. To assess agreement between noninvasive blood pressure (NIBP) oscillometrically-derived values from a multiparameter monitor (Datex Ohmeda S/5 Compact) with those obtained by invasive blood pressure (IBP) measurement in anaesthetised horses undergoing elective surgery. Methods: Prospective clinical study. Methods: A total of 40 healthy adult horses. Methods: Horses were anaesthetised with various anaesthetic protocols (based on clinical requirements). Depending on positioning, cannulation of the facial or lateral metatarsal artery was performed for IBP measurement. The cannula was connected vi...
Oxytocin treatment does not change cardiovascular parameters, hematology and plasma electrolytes in parturient horse mares. In mares, foaling is associated with changes in hematology, plasma electrolytes, blood pressure and heart rate and it has been hypothesized that these are induced by oxytocin. To test this hypothesis, mares (n = 8-14/group) were treated with oxytocin (OT; 20 I.U.) or saline (CON) at 1 h (test A) and 12 h after foaling (test B) and during first postpartum diestrus (test C). Heart rate, heart rate variability (HRV), atrioventricular blocks, salivary cortisol concentration, blood pressure, plasma electrolytes and blood count were determined. Heart rate decreased from test A to C (P < 0.001)...
Effects of dobutamine hydrochloride on cardiovascular function in horses anesthetized with isoflurane with or without acepromazine maleate premedication. OBJECTIVE To determine the effects of acepromazine maleate premedication on cardiovascular function before and after infusion of dobutamine hydrochloride for 30 minutes in isoflurane-anesthetized horses. ANIMALS 6 healthy adult horses. PROCEDURES Each horse was anesthetized once following premedication with acepromazine (0.02 mg/kg, IV) administered 30 minutes prior to anesthetic induction (ACP+ treatment) and once without premedication (ACP- treatment). Anesthesia was induced with IV administration of xylazine hydrochloride (0.8 mg/kg), ketamine hydrochloride (2.2 mg/kg), and diazepam (0.08 m...
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 10Â ...
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)...