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.
Effect of physiological and pharmacological stress on heart rate, blood pressure, and echocardiographic measurements in healthy Warmblood horses. Echocardiographic measurements are important prognostic indicators but might be influenced by heart rate and blood pressure. This is particularly important when comparing repeated examinations. Objective: To determine the effect of physiological stress at mildly increased heart rates and pharmacological challenge using IV administration of N-butylscopolammonium bromide and metamizol sodium on heart rate, blood pressure, and echocardiographic measurements. Methods: Twenty healthy Warmblood horses. Methods: Randomized crossover study. Horses were examined echocardiographically by 2-dimensional, ...
Evaluation of the agreement between lingual and thoracic limb noninvasive blood pressure with invasive blood pressure measurements in anaesthetized horses. To evaluate the agreement between noninvasive arterial blood pressure (NIBP) measured from the tongue and thoracic limb with invasive blood pressure (IBP), and to compare NIBP measured from the tongue and thoracic limb in anaesthetized horses. Methods: Prospective clinical study. Methods: A group of eight client-owned healthy horses anaesthetized for scheduled procedures, American Society of Anesthesiologists classification I-II, weighing (mean ± standard deviation) 498 ± 91 kg and aged 7.8 ± 6.75 years. Methods: Animals were premedicated with intravenous (IV) romifidine (0.04-0.08 mg kg-1)...
Pharmacodynamics and pharmacokinetics of nalbuphine in xylazine‑sedated horses. This study describes the selected pharmacodynamics and pharmacokinetics of nalbuphine (NAL) in xylazine (XYL)‑sedated horses. Five adult healthy horses were randomly received 2 treatments at a 1‑week interval; XYL treatment (0.55 mg/kg IV) and XYL/NAL treatment (XYL, 0.55 mg/kg IV; NAL, 0.3 mg/kg IV). The measured pharmacodynamic variables were sedative and analgesic effects and the effect on ataxia and some physiological parameters. for the pharmacokinetics of NAL, its plasma concentrations were measured using HPLC and a 2‑compartment analysis was performed. Greater and prolonged sedati...
Cardiovascular effects of intravenous morphine in anesthetized horse. To investigate whether morphine causes a change in mean arterial blood pressure (MAP) heart rate (HR) and oxygen extraction (OE) rate in healthy horses anesthetized with isoflurane and a dexmedetomidine infusion. Unassigned: The study design was prospective clinical, randomized, blinded two groups including 33 horses. All horses were sedated with romifidine IV, and anesthesia was induced with midazolam IV and ketamine IV and maintained with isoflurane in oxygen and medical air and a dexmedetomidine infusion. As a baseline venous and arterial blood, HR and MAP were sampled. Thereafter either mo...
Cardiovascular changes in horses with atrial fibrillation and high thyroid hormone concentration: a case-control study. Hyperthyroidism is a predisposing factor for atrial fibrillation (AF) in humans. The relationship between high thyroid hormone (TH) and AF in horses has not been evaluated. Objective: The aim of this study is to identify whether (1) high TH concentrations were present in horses with AF, (2) other cardiovascular effects were observed in horses with high TH and AF, and (3) TH status affected recurrence rate. Methods: Twenty-three horses presented with naturally occurring AF. Methods: Prospective case-control clinical study. Thyroid hormone concentration was measured in horses presenting with AF....
Effects of 7.2% hypertonic saline solution on cardiovascular parameters and endogenous arginine vasopressin secretion in euvolemic isoflurane-anesthetized horses. To compare the effects of 7.2% hypertonic and 0.9% isotonic saline (sodium chloride) solutions on cardiovascular parameters and plasma arginine vasopressin (AVP) concentrations in healthy, isoflurane-anesthetized horses. Methods: 8 healthy horses. Methods: In a prospective, randomized, crossover study, horses were anesthetized with isoflurane twice with a 14-day washout period between anesthetic episodes. While anesthetized, horses received a bolus (4 mL/kg) of 7.2% hypertonic saline solution (HS) or 0.9% isotonic saline solution (IS). Heart rate; systolic, mean, and diastolic arterial blood p...
Nitric oxide synthase inhibition reveals differences in the nitric oxide pathway in previously laminitic ponies. Previously laminitic (PL) ponies are reported to have higher blood pressure than non laminitic (NL) ponies. This relative hypertension may be related to endothelial cell dysfunction, similar to humans with metabolic syndrome. To investigate the relationship between laminitis predisposition and endothelial dysfunction, the effect of nitric oxide synthase (NOS) inhibition on the change in circulating nitric oxide (NO) concentrations and systemic blood pressure (BP) was determined. An intravenous NO sensor was used to measure changes in blood NO concentration during and after intravenous infusion...
Nasal and tracheobronchial nitric oxide production and its influence on oxygenation in horses undergoing total intravenous anaesthesia. The present study aimed to investigate the effect of endotracheal intubation on nasal and tracheal endogenous NO concentrations, gas exchange and oxygenation in horses undergoing general anaesthesia. In many species a major part of physiological nitric oxide (NO) production takes place in the nasopharynx. Inhaled NO acts as a pulmonary vasodilator and regulates lung perfusion and endotracheal intubation bypasses the nasopharynx. Six horses were randomly assigned to either the "intubated" (INT) or the "non-intubated" (nINT) treatment group. Horses were premedicated with dexmedetomidine (5 μg...
Agreement of High-Definition Oscillometry (HDO) and Invasive Blood Pressure Measurements at a Metatarsal Artery in Isoflurane-Anaesthetised Horses. High-definition oscillometry (HDO) over the metatarsal artery (MA) in anaesthetised horses has not yet been evaluated. This study aimed to assess agreement between HDO and invasive blood pressure (IBP) at the metatarsal artery, and to evaluate compliance with the American College of Veterinary Internal Medicine (ACVIM) consensus guidelines. In this experimental study, 11 horses underwent general anaesthesia for an unrelated, terminal surgical trial. Instrumentation included an IBP catheter in one and an HDO cuff placed over the contralateral MA, as well as thermodilution catheters. Systolic ar...
Bias Associated with Peripheral Non-Invasive Compared to Invasive Arterial Blood Pressure Monitoring in Healthy Anaesthetised and Standing Horses Using the Bionet BM7Vet. To compare arterial blood pressure (ABP) measured invasively (IBP) to ABP measured non-invasively (NIBP) via oscillometry in healthy anaesthetised and standing horses using the Bionet BM7Vet. Fourteen horses were anaesthetised for elective procedures (anaesthetised group) and 10 horses were enrolled for standing blood pressure manipulation (standing group). In both groups, IBP and NIBP-corrected to heart level were measured every 3 min using the Bionet BM7Vet. The overall mean difference (bias), standard deviation and limits of agreement (LOA) were calculated for paired IBP and NIBP systolic (...
Hearing hoofbeats? Think head and neck trauma: a 10-year NTDB analysis of equestrian-related trauma in the USA. There is a paucity of evidence about traumatic injuries and their sequelae sustained due to equestrian injuries nationally. Methods: Retrospective study analyzing National Trauma Data Bank data from 2007 to 2016. Variables collected included age, sex, race, payer status, Injury Severity Score (ISS), hospital length of stay, Glasgow Coma Scale, systolic blood pressure (SBP) at presentation, discharge disposition, and mortality. Patient data were analyzed by anatomic region. Results: The most frequent type of injury was in the thorax, but head and neck injuries produced the highest mortality. In...
Neuromuscular blockade with atracurium for ophthalmic surgery in horses-Effects on surgical and anesthetic characteristics and recovery quality. To study the surgical, anesthetic and recovery qualities of horses receiving either a neuromuscular blocking agent (atracurium) or intravenous lidocaine (treatment groups A and L, respectively). Methods: A total of thirty horses presented for ocular surgery were used in this study. Methods: Horses were randomly assigned to receive either atracurium (group A) or a lidocaine constant rate infusion (group L). Surgical quality was graded on a scale from 1 (excellent)-5 (poor). While anesthetized, the heart rate, oxygen saturation and mean arterial blood pressure, and end-expiratory carbon dioxide ...
Effect of a long-term high-energy diet on cardiovascular parameters in Shetland pony mares. Changes in cardiovascular parameters, including blood pressure (BP) and cardiac anatomical dimensions, are an inconsistent feature of the equine metabolic syndrome. The order in which these changes arise is unknown. Objective: Determine the order in which EMS-associated changes in cardiovascular parameters arise. Methods: Twenty Shetland pony mares. Methods: High-energy (HE) diet mares were fed 200% of net energy requirements for 1 (n = 3) or 2 (n = 7) consecutive diet-years, with 17 weeks of hay-only between years. Noninvasive BP measurements and echocardiograms were performed during bo...
Evaluation of the sublingual microcirculation with sidestream dark field video microscopy in horses anesthetized for an elective procedure or intestinal surgery. To compare the sublingual microcirculation between healthy horses anesthetized for elective procedures and horses with colic anesthetized for abdominal surgery and to determine the effect of mean arterial blood pressure (MAP) on the microcirculation. Methods: 9 horses in the elective group and 8 horses in the colic group. Methods: Sublingual microcirculation was assessed with sidestream dark field video microscopy. Videos were captured at 3 time points during anesthesia. Recorded microvasculature parameters were De Backer score (DBS), total density of perfused vessels (PVD) and small vessels (...
The effect of xylazine on intracranial pressure in anesthetized and standing horses. To determine the effect of xylazine on intracranial pressure (ICP) in standing compared to isoflurane-anesthetized horses. Methods: Prospective, crossover study design. Methods: University Teaching Hospital. Methods: Six adult horses donated to the University. Horses were determined to be healthy via physical examination, complete blood count, and neurological evaluation. Methods: Horses were anesthetized, maintained on isoflurane in oxygen in left lateral recumbency, and ventilated to normocapnia. Horses were instrumented for intraparenchymal measurement of ICP, invasive blood pressure, pulse...
The use of electrical impedance tomography (EIT) to evaluate pulse rate in anaesthetised horses. Electrical impedance tomography (EIT) provides clinically useful lung images; however, it would be an advantage to extract additional cardiovascular information from the data. The aim of this study was to evaluate if cardiac-related changes measured by EIT can be used to measure pulse rate (PR) under physiological as well as high and low blood pressure states in anaesthetised horses. Electrical impedance tomography data and PR from seven horses anaesthetised in dorsal recumbency were recorded over 1 min during mechanical ventilation and 1 min of apnoea. Data were collected at four measurement ...
Effects of head position on internal and external carotid pressures in standing sedated horses. The effects of head position on internal carotid artery (ICA) and external carotid artery (ECA) pressures in standing sedated horses were evaluated in this study. The common carotid artery (CCA) was catheterized in 6 horses using an ultrasound-guided technique to facilitate placement of a pressure transducer within the ICA and ECA at the level of the guttural pouch. Transducer position was confirmed by endoscopic visualization. Mean arterial pressure (MAP) was measured with horses in both a head-up and head-down position. The dorsal metatarsal artery was catheterized as a control. Maintaining ...
Analgesic and Cardiopulmonary Effects of Epidural Romifidine and Morphine Combination in Horses. The study aim is to compare the effects of epidural administration of two different doses of romifidine combined with morphine in horses. A prospective crossover blinded experimental design was used. Five adult healthy horses two males and three females with a mean body weight of 380 ± 45 Kg (335-425 kg), were studied. Treatments consisted of romifidine 30 μg/kg (R30) or 60 μg/kg (R60) combined with morphine 0.1 mg/kg with a washout interval of 72 hours, administered through an epidural catheter placed at the first intercoccygeal space. Heart rate (HR) and respiratory rate (f), pH, blood ga...
Pharmacokinetics and pharmacodynamics of l-methadone in isoflurane-anaesthetized and mechanically ventilated ponies. To evaluate the pharmacokinetics and selected pharmacodynamic effects of a commercially available l-methadone/fenpipramide combination administered to isoflurane anaesthetized ponies. Methods: Prospective single-group interventional study. Methods: A group of six healthy adult research ponies (four mares, two geldings). Methods: Ponies were sedated with intravenous (IV) detomidine (0.02 mg kg) and butorphanol (0.01 mg kg) for an unrelated study. Additional IV detomidine (0.004 mg kg) was administered 85 minutes later, followed by induction of anaesthesia using IV diazepam (0.05 mg kg) and keta...
Changes in Arterial Blood Pressure and Oxygen Tension as a Result of Hoisting in Isoflurane Anesthetized Healthy Adult Horses. In anesthetized adult horses, changes in recumbency can influence the cardiovascular system but how arterial blood pressures and oxygen tension change in isoflurane anesthetized animals as a direct result of hoisting has not been investigated. To evaluate effects of hoisting on hemodynamic function and pulmonary gas exchange in isoflurane-anesthetized horses. Prospective, experimental study. Six adult horses were anesthetized three times using isoflurane in pure oxygen (inspired fraction 0.9-1.0), and allowed breathing spontaneously in lateral recumbency. After 45 min horses were hoisted u...
The effect of diet-induced obesity and pasture on blood pressure and serum cortisol in Standardbred mares. Obesity is associated with insulin resistance, vascular dysfunction and altered cortisol metabolism both in humans and in horses. Objective: Evaluate the effect of weight gain induced by a haylage diet low in nonstructural carbohydrates (NSC) on insulin sensitivity, blood pressure and serum cortisol concentrations. Methods: In vivo experiment. Methods: Nine adult Standardbred mares fed a fat supplemented haylage diet at 250% of the horses' daily metabolisable energy requirements for 22 weeks. Horses were then turned out on pasture for 4 weeks. Insulin sensitivity (SI ) was measured before an...
Pharmacokinetics of xylazine after 2-, 4-, and 6-hr durations of continuous rate infusions in horses. Intravenous (i.v.) bolus administration of xylazine (XYL) (0.5 mg/kg) immediately followed by a continuous rate infusion (CRI) of 1 mg kg hr for 2, 4, and 6 hr produced immediate sedation, which lasted throughout the duration of the CRI. Heart rate decreased and blood pressure increased significantly (p > .05) in all horses during the first 15 min of infusion, both returned to and then remained at baseline during the duration of the infusion. Compartmental models were used to investigate the pharmacokinetics of XYL administration. Plasma concentration-time curves following bolus an...
Behavioral and Cardiopulmonary Effects of a Constant Rate Infusion of Remifentanil-Xylazine for Sedation in Horses. Xylazine and remifentanil in constant rate infusion (CRI) could be used for sedation in horses without adverse effects. The objective was to evaluate behavioral and cardiopulmonary effects of an intravenous (IV) infusion of xylazine and remifentanil for sedation in horses. Xylazine (0.8 mg/kg IV) followed after 3 minutes by a CRI of xylazine and remifentanil (0.65 mg/kg/h and 6 μg/kg/h, respectively) was administered in 10 healthy horses for 60 minutes. Sedation, ataxia, and cardiopulmonary, hematological, and blood gases variables were evaluated. Heart rate decreased significantly durin...
Effects of dobutamine on cardiovascular function and oxygen delivery in standing horses. Dobutamine is routinely used to improve cardiovascular function in anaesthetized horses. However, dobutamine in conscious horses is insufficiently investigated. Ten research horses that were already instrumented for a preceding trial were included into the study. Cardiovascular variables were recorded and blood samples taken after instrumentation (Baseline), before starting dobutamine and after 10 min of dobutamine infusion (2 µg kg min ). A significant increase in systemic blood pressure, mean pulmonary artery pressure and right atrial pressure, and a decrease in heart rate were observe...
Age-related differences in blood pressure, ultrasound-derived arterial diameters and arterial wall stiffness parameters in horses. Arterial rupture mainly affects older horses. The reason why older horses are more prone to arterial rupture and which underlying vascular changes predispose older horses to aortic rupture is still unclear. Objective: To investigate the effect of ageing on the equine arterial wall and blood pressure. Methods: Cohort study. Methods: Non-invasive blood pressure measurement using a tail cuff and vascular ultrasound from aorta, common carotid artery and external iliac artery was performed in 50 healthy young (3-7 years) and 50 healthy old Warmblood horses (>18 years). Arterial diameters and c...
Differences in ultrasound-derived arterial wall stiffness parameters and noninvasive blood pressure between Friesian horses and Warmblood horses. Aortic rupture is more common in Friesians compared to Warmbloods, which might be related to differences in arterial wall composition and, as such, arterial wall stiffness (AWS). Currently, nothing is known about differences in AWS between these breeds. Objective: Comparison of AWS parameters and noninvasive blood pressure between Friesians and Warmbloods. Methods: One hundred one healthy Friesians and 101 age-matched healthy Warmbloods. Methods: Two-dimensional and pulsed-wave Doppler ultrasound examination was performed of the aorta, common carotid artery, and external iliac artery to define...
Agreement between invasive and oscillometric arterial blood pressure measurements using the LifeWindow multiparameter monitor and two cuff sizes in anesthetized adult horses. To assess agreement between oscillometric noninvasive blood pressure (NIBP) measurements using LifeWindow monitors (LW9xVet and LW6000V) and invasive blood pressure (IBP). To assess the agreement of NIBP readings using a ratio of cuff width to mid-cannon circumference of 25% and 40%. Methods: Prospective, randomized clinical study. Methods: A total of 43 adult horses undergoing general anesthesia in dorsal recumbency for different procedures. Methods: Anesthetic protocols varied according to clinician preference. IBP measurement was achieved after cannulation of the facial artery and connectio...
Pharmacopuncture Analgesia Using Flunixin Meglumine Injection into the Acupoint GV1 (Ho Hai) After Elective Castration in Horses. The study evaluated the effect of a 1/10 dose of flunixin meglumine administered into the governing vessel 1 (GV1) acupoint in horses that underwent castration. Twenty animals received 0.02 mg/kg detomidine intravenously, followed by 2.2 mg/kg ketamine and 0.1 mg/kg diazepam by the same route, and also a local anesthesia with 30 mL lidocaine. As postoperative analgesia, the animals received 1.1 mg/kg flunixin meglumine IV (FIV) or 0.11 mg/kg flunixin meglumine into the GV1 acupoint (FGV). Behavioral parameters were assessed 12 hours before the procedure (baseline) and at 4, 6, 12, and 2...
Effect of Methadone Combined With Acepromazine or Detomidine on Sedation and Dissociative Anesthesia in Healthy Horses. The aim of this study was to compare the effects of methadone combined with detomidine or acepromazine on the quality of sedation and its influence over dissociative anesthesia in healthy horses. In a crossover design, seven horses were administered with 0.1 mg/kg methadone and 0.02 mg/kg detomidine intravenously (group MD) or 0.1 mg/kg methadone and 0.05 mg/kg acepromazine intravenously (group MA). Subsequently, anesthesia was induced with a combination of 2.2 mg/kg ketamine and 0.1 mg/kg midazolam intravenously. Descriptive scales and footages were used to evaluate the quality of sedat...
Aortic, common carotid and external iliac artery arterial wall stiffness parameters in horses: Inter-day and inter-observer and intra-observer measurement variability. In human medicine, local and regional arterial wall stiffness (AWS) parameters are routinely used to assess the vascular health. In horses, information regarding reproducibility of ultrasonographically derived AWS parameters is lacking. Objective: To evaluate the inter-day and inter-observer and intra-observer measurement variability of both local and regional AWS parameters in horses. Methods: Experimental study. Methods: In 10 healthy, adult Warmblood horses, B-, M-mode and pulsed-wave Doppler ultrasound images were collected on two different days from aorta, cranial and caudal common caroti...