Hyperglycemic, hyperosmolar syndrome in feline diabetics: 17 cases (1995–2001)

Objective: The purposes of this study were to characterize the hyperglycemic, hyperosmolar syndrome (HHS), also known as nonketotic hyperosmolar diabetes, in cats; to determine the prevalence of HHS in the diabetic cat population in the emergency room; to document the outcome in cats with HHS; and to identify any predisposing factors or predictors of survival. Design: Retrospective study. Setting: An emergency service at a veterinary teaching hospital located in a major metropolitan area. Animals: The case records of 17 cats with hyperglycemic, hyperosmolar syndrome presenting from 1995 to 2001 were evaluated. An additional 37 cats with diabetic ketoacidosis and 80 cats with diabetes mellitus served as comparison groups. Interventions: None. Measurements and main results: Signalment, history, physical examination findings, clinico‐pathologic data, concurrent disease, and outcome were recorded. Hyperglycemic, hyperosmolar syndrome was seen in older cats that were often long‐standing diabetics receiving insulin for many months. Client concerns included polydipsia, polyuria, and lethargy. Neurologic and respiratory signs occurred frequently. Evaluation at presentation revealed profound dehydration, lactic acidosis, and azotemia. Serious concurrent diseases that likely contributed to the development of the HHS crisis were diagnosed in 88% (15/17) of the HHS cats. The most common concurrent diseases were renal failure, respiratory compromise, infection, congestive heart failure, neoplasia, and gastrointestinal tract disease. Pancreatitis and hepatic disease did not occur frequently in this diabetic cat population. Sixty‐five percent of HHS cats did not survive the initial hospitalization, with most dying or being euthanized within 10 hours of presentation. The long‐term survival rate was low (12%). Conclusions: HHS is a serious life‐threatening form of diabetic crisis and cats with HHS often have other severe systemic diseases. Cats with diabetes and concurrent disease, especially renal failure and congestive heart failure, are at increased risk of HHS and should be closely monitored for signs of crisis. The mortality rate for HHS cats is high.     

Comparison of non-invasive cardiac output measurement by partial carbon dioxide rebreathing with the lithium dilution method in anesthetized dogs

Objective: To compare the partial CO₂ rebreathing method (non‐invasive cardiac output [NICO]) and the lithium dilution method (lithium dilution cardiac output [LiDCO]) for cardiac output (CO) measurement in anesthetized dogs. Design: Prospective study. Setting: College of Veterinary Medicine, University of Florida. Animals: Six adult dogs (weight range 22–25.4 kg). Interventions: All animals were instrumented for CO determinations using the LiDCO and NICO methods. Direct blood pressure, heart rate, arterial blood gases, end‐tidal isoflurane (ETI), and CO₂ concentrations were monitored throughout the study. CO was manipulated with dobutamine and isoflurane to allow for intermediate, low, and high CO determinations in that order using LiDCO and NICO. Measurements and main results: A 1.5% ETI produced the intermediate rate of CO, a constant‐rate infusion of dobutamine (1–4 μg/kg/min) and 1.1% ETI, the highest rate, and 2.5–3% ETI, the lowest rate. Measurements were obtained in duplicate or triplicate for the LiDCO and continuously for the NICO method after achieving a stable hemodynamic plane for at least 15 minutes at each level of CO, allowing 5 minutes between measurements. Forty‐seven comparisons were determined. The correlation coefficient (r) between the 2 methods was 0.888 for all determinations. The mean LiDCO and NICO from 47 measurements were 155.9±78.7 mL/kg/min (range, 49.6–303.2) and 146.6±62.9 mL/kg/min (50–290.3), respectively. The bias between LiDCO and NICO estimations was 9.3 (?60.7 to +79.4) mL/kg/min (mean and 95% confidence interval). The mean (mL/kg/min) of the differences of LiDCO–NICO was 1.11 × NICO. The relative error was 2.4±24.7%. As CO increased, the relative difference between the methods also increased. Conclusions: The NICO is a viable non‐invasive method for CO determination in the dog and compares well with the LiDCO.     

AORTO-CARDIAC FISTULAS IN SEVEN HORSES

This report describes the history, clinical, electrocardiographic and echocardiographic findings, treatment, outcome, and post-mortem findings in seven horses with aorto-cardiac fistula. Affected horses included 5 stallions, one gelding and one mare; 2 each of the Thoroughbred, Arabian and Standardbred breeds and one Thoroughbred-cross with a mean ± s.d. age of 12 ± 4 years, range 6–18 years. The presenting sings were acute distress (four horses), exercise intolerance (two horses) and the lesion was detected during a routine examination in one horse. Five horses had monomorphic ventricular tachycardia on admission and one other had a history of this arrhythmia. Five horses had a characteristic continuous murmur loudes in the right fourth intercostal space. Echocardiography (six horuses) and/or post-mortem examination (four horses) revealed the horses had aorto-cardiac fistulas arising from the right aortic sinus in all five horses in which the site was recorded. Two horses had ruptured aneurysmall dilatations of the aortic wall at this site. Fistulas extended into the right ventricle in four horses; the right atrium in two horses, the left ventricle in one horse, and five horses had dissecting tracts in the septal myocardium. Horses survived for periods ranging from 24th to 4 years. Aorto-cardiac fistula should be considered in the differential diagnosis for horses presenting with acute distress, bounding arterial pulse, a right-sided continuous murmur and/or monomorphic ventricular tachycardia, particularly in middle-aged or older stallions. Echocardiography is the technique of choice for confirming the diagnosis and demonstrating accompanying cardiac changes.     

ULTRASONOGRAPHIC EXAMINATION OF THE PHARYNX AND LARYNX OF THE NORMAL DOG

Real-time ultrasonographic examination of the canine larynx was performed in 12 normal dogs using a 7.5-mHz mechanical sector scanner combined with a stand-off. A variety of breeds and ages were examined. All examinations were performed in nonsedated, conscious animals. Transverse scans were found to provide the most reliable and interpretable images. Identification of laryngeal structures included the epiglottis, laryngeal and cricoid cartilages, and the vocal cords. In conscious animals, abduction and adduction of the vocal cords associated with respiration could be identified if the animal was made to pant during the examination. Movement of the vocal cords could also be quantified by pulse-wave Doppler recording. In all animals, recordings were made during inspiration only, with muscular vibration at a rate less than 0.1 m/s.     

Practicality, Usefulness, and Limits of Pulse Oximetry in Critical Small Animal Patients

Pulse oximetry holds the promise of wide application for monitoring and assessing pulmonary function in small animal patients. Although the saturation as read by pulse oximetry (SpO2) has previously been shown to be accurate in healthy dogs, its accuracy and usefulness have not been demonstrated in critical small animal patients. The present study assessed the accuracy and usefulness of a pulse oximeter (Ohmeda Biox 3740, Ohmeda, Louisville, CO) in a small animal intensive care unit. The instrument yielded readings in 48 of 51 attempts in 33 animals (25 dogs, 8 cats). Criteria were developed to reject spurious readings; when these criteria were applied, the actual calculated SaO2 differed from the SpO2 by O.26 +2.2%, with a correlation of 0.87 (p<0.0001). The 95% confidence interval was +4.4%, comparable to the accepted level in humans. No ill effects from SpO2 were apparent in the patients, and the instrument was useful in monitoring the progress of critical animals. However, uncritical use of the oximeter could have led to gross patient mismanagement, as SpO2 readings as much as 29% different from SaO2 were sometimes obtained.     

ULTRASONOGRAPHY VERSUS RADIOGRAPHY FOR DETECTION OF FLUID IN THE CANINE TYMPANIC BULLA

The tympanic bullae of 20 previously healthy cadaver animals were randomly filled with sterile saline or air. The heads were positioned using tape ties and a rostrocaudal open mouth radiograph taken. The resulting radiographs were assessed by a blinded ECVDI diplomate, with each tympanic bulla being recorded as being either air or fluid filled. Ultrasound examination of the bullae was performed, by a blinded assessor, using a B-mode 5 mHz sector probe (Sonotron-VingMed Sound A/S, PO Box 141, N3191, Horten, Norway) operating at 3 mHz. Each bulla was recorded as being either air or fluid filled. Results of radiography and ultrasonography were each compared to the actual status of the bulla in a chi square analysis. Sensitivity of radiography was 80%, with specificity of 65%. Ultrasonographic sensitivity was 100% and specificity 100%. Ultrasonography may in future provide a cheap, noninvasive, rapid and widely available method for diagnosing otitis media in clinical cases.     

Effects of season, age and increased photoperiod on reproductive hormone concentrations and testicular diameters in thoroughbred stallions

Testicular diameters and monthly blood samples were obtained from 83 stallions aged 4 to 22 years that were maintained on Central Kentucky Thoroughbred stud farms. The effects of age, season, and exposure to increased photoperiod (16 hours light/day, December 15 to April 1) on testicular diameters and plasma concentrations of FSH, LH and testosterone were studied.The results indicated that Thoroughbred stallions show distinct seasonal and age related changes in most of the reproductive parameters studied and that exposure of such stallions to increased photoperiod produced significant alterations in these changes. Although lighting stimulated testicular growth and testosterone secretion early in the breeding season such changes were short lived. Lighted stallions appeared to become refractory to the lighting program since both testicular size and plasma testosterone concentrations were significantly reduced by June.     

Inability of goldenseal to interfere with the detection of morphine in urine

Preparations of the herb, goldenseal, have been used in an attempt to thwart detection of morphine in urine of human addicts and racing horses. To assess the potential of goldenseal to interfere with equine drug detection, horses were dosed with morphine (0.1 mg/kg IV) and, in one experimental series, also with goldenseal (60 mg/kg, p.o.). Goldenseal resulted in significant increases in urine volume, specific gravity and acidity. A significant decrease in total morphine excreted occurred 5–6 hours after dosing. It was concluded that with inclusion of an efficient hydrolysis step in the analysis, goldenseal was unlikely to interfere with urine tests for morphine, even if water loading was included in the dosing regimen.