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Biomedical subjects

Kevin T T Corley

Publications and source records attributed to Kevin T T Corley.

11 recordsLinked to original sources

Morphine-associated pruritus after single extradural administration in a horse.

Pruritus following a single administration of 100 microg kg(-1) of preservative-free morphine sulphate given via an extradural catheter was seen in a 580 kg horse. The catheter was placed in the first intercoccygeal space. Focal irritation, represented by both local alopecia over the left gluteal muscles and serum exudation, occurred 4-8 hours after injection. This was attributed to the extradural morphine administration.

Analgesics, Opioid↗

Resuscitation and emergency management for neonatal foals.

Early intervention can dramatically alter outcome in foals. Cardio-pulmonary cerebral resuscitation can be successful and clinically worthwhile when applied to foals that arrest as part of the birthing process. Readily available equipment and an ordered plan starting with addressing the respiratory system (airway and breathing) followed by the circulatory system (circulation and drugs) are the keys to success. Hypoglycemia is common in foals that are not nursing and in septic foals. Support of serum glucose can be an important emergency treatment. Respiratory support with oxygen therapy should be considered in all foals following resuscitation and dystocia. Other foals that are likely to benefit from oxygen are those that are dyspneic, cyanotic, meconium-stained after birth,or recumbent. Emergency therapies, applied correctly, are expected to result in decreased mortality and morbidity.

Animals↗

Use of lithium dilution and pulse contour analysis cardiac output determination in anaesthetized horses: a clinical evaluation.

OBJECTIVE: To assess the suitability of a human algorithm for calculation of continuous cardiac output from the arterial pulse waveform, in anaesthetized horses. STUDY DESIGN: Prospective clinical study. ANIMALS: Twenty-four clinical cases undergoing anaesthesia for various conditions. MATERIALS AND METHODS: Cardiac output (Qt), measured by lithium dilution (QtLiDCO), was compared with a preceding, calibrated Qt measured from the pulse waveform (QtPulse). These comparisons were repeated every 20-30 minutes. Positive inotropes or vasopressors were administered when clinically indicated. Cardiac indices from 30.7 to 114.9 mL kg(-1) minute(-1) were recorded. Unusually shaped QtLiDCO curves were rejected and the measurement was repeated immediately. RESULTS: Eighty-nine comparisons were made between QtLiDCO and QtPulse. The bias between the mean (+/-SD) of the two methods (QtLiDCO - QtPulse) was -0.07 L minute(-1)(+/-3.08) (0.24 +/- 6.48 mL kg(-1) minute(-1)). The limits of agreement were -12.72 and 13.2 mL kg(-1) minute(-1) (Bland & Altman 1986; Mantha et al. 2000). Linear regression analysis demonstrated a correlation coefficient (r2) of 0.89. Cardiac output in individual patients varied from 49.1 to 183% of the initial measurement at the time of calibration. Linear regression of log-transformed Qt variation for each method found a mean difference of 9% with limits of agreement of -4.1 to 22.1%. CONCLUSIONS AND CLINICAL RELEVANCE: This method of pulse contour analysis is a relatively noninvasive and reliable way of monitoring continuous Qt in the horse under anaesthesia. The ability to easily monitor Qt might decrease morbidity and mortality in the anaesthetized horse.

Anesthesia, General↗

Inotropes and vasopressors in adults and foals.

Successful treatment with inotropes and vasopressors depends on an understanding of the interplay of flow, pressure, and resistance in the cardiovascular system and an appreciation of the pathophysiologic mechanisms leading to inadequate tissue perfusion. Any treatment strategy is necessarily a compromise between the requirements of different vascular beds.Furthermore. the underlying hemodynamic derangements can change rapidly. Therefore. inotropes and vasopressors should be titrated to measures of improved hemodynamic status, and the treatments should be frequently reviewed.

Animals↗

Risk factors and prevalence of injuries in horses during various types of steeplechase races.

OBJECTIVE: To identify the types of injuries sustained by horses that competed in steeplechase races and determine the prevalence of and risk factors for those injuries. DESIGN: Prospective study. ANIMALS: 2,680 horses that competed in various types of steeplechase races from 1996 through 2000. PROCEDURE: Data regarding races; environment; equipment problems; the number of horses that entered, started, and finished races; the number of riders that fell; and the number of horses that were slowed or stopped by the rider, ran off the course, fell, and sustained injuries or physical abnormalities during races were collected on a standard form by the official veterinarian who attended each meet. Data from all meets were not recorded; however, in recorded meets, data from every race were reported. RESULTS: Data for 197 hurdle, 65 timber, 76 flat, and 8 mixed races were recorded. Nine (3.4/1,000 horses that started in races) horses died or were euthanatized, and 7 of those were associated with catastrophic musculoskeletal injury. Seven fractures were recorded. Four fractures involved forelimbs, 1 involved a hind limb, and 2 involved the cervical portion of the vertebral column. All horses with fractures were euthanatized. Deep or hard course conditions were associated with an increased risk of breakdown injuries. CONCLUSIONS AND CLINICAL RELEVANCE: Successful development and implementation of strategies to prevent injuries and death in horses in steeplechase races depend on a clear understanding of the types and prevalence of injuries involved and risk factors associated with those injuries.

Animals↗

Veterinary critical care.

Veterinary species experience similar perturbations of their health to those of human patients. When the long-term prognosis is good and providing suffering can be minimized, animals stand to benefit greatly from recent advances in the field of emergency and critical care. Outcomes in many conditions in small and large animals have improved markedly in the last 15 years, as management has improved, making the financial and emotional investment in critical care worthwhile for many owners.

Animals↗

Small intestinal volvulus in 115 horses: 1988-2000.

OBJECTIVE: To evaluate the historical data, signalment, clinical signs, results of laboratory analyses, treatment, and outcome of horses with small intestinal (SI) volvulus. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: One hundred and fifteen client-owned horses, aged 1 month to 21 years. METHODS: Clinical signs, laboratory data, surgical or necropsy findings, and outcome for horses with SI volvulus were obtained from medical records, identified by computer search and manual review. RESULTS: There was no statistical difference in signalment between cases and the hospital population. Seventy-four percent of horses were >/=3 years. There were considerable variations in clinical signs on admission; high heart rate and signs of severe pain were not consistent features. Examination per rectum identified distended small intestine in only 69% of horses. One hundred horses had surgery, and small intestine resection was performed in 25. Eighty-four horses were recovered from surgery, and 67 horses survived to hospital discharge (80% of horses recovered from surgery, 58% of 115 horses). Forty-eight percent that were ultimately discharged had a post-operative complication and these horses had a longer average stay than horses with no complication (11 days versus 8.9 days). CONCLUSIONS: We identified 115 horses with primary SI volvulus over a 12-year period. We found that the population of horses with this lesion was older than has previously been reported and that the prognosis for post-operative survival to hospital discharge is good (80%). Post-operative complications were common, and affected approximately half the horses that were ultimately discharged from the hospital. CLINICAL RELEVANCE: This information may aid diagnosis and prognosis and guide decision making for horses with this condition.

Animals↗

Factors associated with mortality and morbidity in small intestinal volvulus in horses.

OBJECTIVE: To determine historical, physical, and clinical factors that may affect morbidity and mortality in horses with small intestinal volvulus unrelated to other causes (e.g., incarceration, lipoma, etc.). STUDY DESIGN: Retrospective study. ANIMALS: Client-owned horses (115), aged 1 month to 21 years. METHODS: Data were obtained from medical records, identified by computer search and manual review. Continuous variables were compared between affected and non-affected horses with Mann-Whitney U-tests and non-continuous variables with Fisher's exact test (2 x 2 tables) or chi(2)-tests (larger tables). Stepwise logistic regression analysis was used to develop a multivariable model of the risk factors, taking account of confounding and interaction. RESULTS: Eighty percent of horses recovered from surgery survived to hospital discharge. Neither age, breed, nor sex was related to mortality. Survivors had a significantly lower heart rate, shorter capillary refill time, and better mucous membrane color. Variables associated with worsening cardiovascular status, increased hemoconcentration, and exudation of cells and protein into peritoneal fluid were significantly associated with non-survival. After recovery from surgery, the most serious complication was colic, which was significantly associated with non-survival (P=.028) as was a second celiotomy (P<.01). Both of these complications were associated with a jejunocecostomy during the first surgery. CONCLUSIONS: Significant differences in the clinical and clinicopathologic signs were identified between survivors and non-survivors. CLINICAL RELEVANCE: These findings can be used to make a scientific assessment of prognosis in the pre-operative, operative, and post-operative management of horses with small intestinal volvulus.

Animals↗

Cardiac output technologies with special reference to the horse.

Critical illness, anesthesia, primary cardiovascular disease, and exercise may result in marked hemodynamic alterations. Measuring cardiac output (CO) is central to defining these alterations for both clinician and researcher. In the past 10 years, several new methods of measuring CO have been developed for the human medical market. Some of these methods are now validated in the horse and are in clinical use. The Fick method has been used in equine research for more than a century. It depends on simultaneous measurement of mixed venous (pulmonary arterial) and peripheral arterial oxygen content and oxygen uptake by the lungs. The technique is technically demanding, which restricts its clinical use. Indicator dilution techniques, with indocyanine green, cold (thermodilution), or lithium as the marker, have also been widely used in the horse. The indocyanine technique is cumbersome, and thermodilution requires right heart catheterization, which is not a benign procedure, making both of these methods less than ideal for clinical use. Lithium dilution requires catheterization of a peripheral artery and a jugular vein. It has recently been validated in anesthetized adult horses and neonatal foals. Doppler echocardiography is a noninvasive ultrasound-based technique. More accurate measurements are obtained with transesophageal than with transthoracic measurements; however, both methods require considerable technical expertise. Bioimpedance and pulse contour analysis are 2 new methods that have yet to be validated in the horse. With the currently available technology, lithium dilution appears to be the method of measuring CO best suited to the equine clinic.

Animals↗

Effects of fenoldopam mesylate on systemic hemodynamics and indices of renal function in normotensive neonatal foals.

BACKGROUND: Fenoldopam mesylate, a dopamine-1 receptor agonist, has dose- and species-dependent effects on hemodynamics and renal function. The effects of this drug in normotensive neonatal foals have not been reported. HYPOTHESIS: Two doses of fenoldopam would result in distinct changes in the systemic circulation, urine output, and creatinine clearance of neonatal foals. ANIMALS: Six Thoroughbred foals. METHODS: Each foal received 2 dosages of fenoldopam (low dose, 0.04 microg/kg/min; high dose, 0.4 microg/kg/min) and a control administration of saline, in a masked, placebo-controlled study. RESULTS: High-dosage fenoldopam had no effect on renal function but caused a significant increase in heart rate and decrease in mean, systolic and diastolic arterial blood pressure compared with saline. Low-dosage fenoldopam had no effects on systemic hemodynamics, significantly increased urine output, and had no significant effect on creatinine clearance or the fractional excretions of sodium, potassium, or chloride compared with saline. CONCLUSIONS AND CLINICAL IMPORTANCE: These data suggest that high-dosage fenoldopam increases heart rate, decreases arterial blood pressure, and has no significant effects on renal function, whereas low-dosage fenoldopam has no significant effects on systemic hemodynamics while increasing urine output. This contrast is unique to this species and warrants further investigation.

Animals↗

Preoperative administration of hydroxyethyl starch or hypertonic saline to horses with colic.

BACKGROUND: Hypertonic saline and hydroxyethyl starches have been proposed as alternatives to isotonic crystalloids for reversal of hypovolemia in horses with colic. However, no direct comparison of these fluids has been performed in a clinical setting. HYPOTHESIS: Preoperative administration of hypertonic saline or pentastarch would produce similar effects on intra operative hemodynamics in horses with colic. ANIMALS: Thirty horses requiring colic surgery were enrolled in this prospective, randomized, open-label clinical trial. Inclusion criteria were owner consent, and at least 2 of 3 clinicopathologic abnormalities: packed cell volume >45%, plasma total solid concentration >8.0 g/dL, and blood lactate concentration >2.5 mM. METHODS: Study horses were randomly assigned to receive 4 mL/kg hypertonic saline or pentastarch before induction of anesthesia. Hemodynamic measurements were recorded every 30 minutes during anesthesia. Cardiac output (CO) was measured by the lithium dilution method. CO and stroke volume (SV) were indexed by body weight. Data were analysed using repeated measures analysis of variance (ANOVA). Post hoc comparisons were performed using the Bonferroni test. RESULTS: Cardiac index (CI) was higher in the pentastarch group compared with the hypertonic saline group from 30 to 150 minutes after induction (P = .04). SV index was higher in the pentastarch group at 30 (P = .025) and 60 minutes (P = .04). Mean arterial pressure of horses in both groups was lower at 90 minutes compared with 30 and 60 minutes. CONCLUSIONS AND CLINICAL IMPORTANCE: Preoperative administration of pentastarch results in better CI than hypertonic saline, for 150 minutes after anesthetic induction. The effect of this improved global blood flow on regional perfusion or clinical outcome remains to be elucidated.

Animals↗