CO-oximetry measurements and antioxidant effects of ascorbic acid and methylene blue in equine methemoglobinemic blood.

OBJECTIVES: To determine the effects of time after sampling on CO-oximetry measurements of equine blood samples and the effects of adding ascorbic acid (AscAc) and methylene blue (MetBlue) to samples with methemoglobinemia. DESIGN: Experimental study. SETTING: University teaching hospital. ANIMALS: Thirty healthy adult horses assigned to 5 groups. INTERVENTIONS: Repeated CO-oximetry determinations were performed on venous (n = 6) and arterial blood samples (n = 7) stored at 0°C for 48 hours. Methemoglobinemia was induced in vitro in 17 additional blood samples. Six were used as untreated controls, 6 had AscAc added, and 5 had MetBlue added. Total hemoglobin, oxyhemoglobin, carboxyhemoglobin, methemoglobin (MetHb), and oxygen saturation of hemoglobin (SO2 ) were measured. MEASUREMENTS AND MAIN RESULTS: Oxyhemoglobin and SO2 increased from 69.8% ± 10.2% and 90% ± 3% to 82.8% ± 7.9% and 99% ± 3%, respectively, after 8 hours in venous blood (mean ± SD, P < 0.001). There was an effect of treatment (P = 0.032) and of time (interaction P = 0.003) on MetHb% in methemoglobinemic samples. The difference in absolute MetHb% from time 0 was as follows: 7.0% (interquartile range [IQR] = 21.2), -0.2% (IQR = 3.5), and -4.4% (IQR = 5.2) at 48 hours in control, AscAc, and MetBlue groups, respectively (P < 0.05). There was no effect of time on MetHb% in the AscAc group (23% [IQR = 52.6] at time 0 to 23.2% [IQR = 56.9] after 48 h). CONCLUSIONS: Storage of blood in ice water to determine O2 Hb and SO2 using a CO-oximeter should not exceed 4 hours. Measurement of MetHb% could be delayed by up to 48 hours if AscAc is added to the sample. MetBlue significantly decreased MetHb% over time. The limitations of this study include the fact that the antioxidant effects of AscAc and MetBlue were evaluated in vitro and not in vivo. Further studies are needed to evaluate different storage temperatures and syringe types.

Stall-side screening potential of a smartphone electrocardiogram recorded over both sides of the thorax in horses.

BACKGROUND: Comparisons between smartphone ECG (SpECG) recordings obtained from the right and left sides of the thorax have not been reported in animals. OBJECTIVES: To evaluate the screening potential of a SpECG obtained from both sides of the thorax and to compare the degree of agreement between the SpECG and a reference ECG (rECG) for measurement of the duration of baseline electrical deflections recorded over both sides of the thorax. ANIMALS: Fifty horses admitted to the equine hospital, university-owned horses, and horses from an endurance riding facility. METHODS: Prospective observational study. Simultaneous rECG and SpECG tracings were recorded on both sides of the thorax and evaluated by 2 experienced observers for interpretability, presence and classification of arrhythmias, and duration of deflections of the electrical baseline. RESULTS: Fifteen (15/50) horses had spontaneous arrhythmias. Excellent agreement was found between the 2 devices (κ = 0.91; P < .001; 95% confidence interval [CI] 0.79-1.03) for the detection of arrhythmias. Significantly more P waves were of diagnostic quality from the right side (20 versus 5, P = .001) and significantly more QRS and QT intervals were of diagnostic quality from the left side (66 versus 38 and 62 versus 34, respectively, P < .001). Substantial agreement for the duration of deflections between devices only was observed for the QRS interval (SpECG left). CONCLUSIONS AND CLINICAL IMPORTANCE: It is important to obtain SpECG tracings from both sides of the thorax in horses. The SpECG is a useful stall-sidearrhythmia-screening tool for some common arrhythmias in horses.

Delayed onset vagus nerve paralysis after occipital condyle fracture in a horse.

Occipital condylar fractures (OCFs) causing delayed onset lower cranial nerve paralysis (LCNPs) are rare. We present a 7-year-old Friesian horse with delayed onset dysphagia caused by vagus nerve (CNX) paralysis and suspicion of glossopharyngeal nerve (CNIX) paralysis developed several days after a minor head injury. Endoscopic examination revealed right laryngeal hemiplegia and intermittent dorsal displacement of the soft palate. An area of submucosal hemorrhage and bulging was appreciated over the dorsal aspect of the medial compartment of the right guttural pouch. Radiological examination of the proximal cervical region showed rotation of the atlas and the presence of a large bone fragment dorsal to the guttural pouches. Occipital condyle fracture with delayed onset cranial nerve paralysis was diagnosed. Delayed onset cranial nerve paralysis causing dysphagia might be a distinguishable sign of OCF in horses. Delayed onset dysphagia after head injury should prompt equine clinicians to evaluate the condition of the atlanto-occipital articulation and skull base.

Mitral Kissing Vegetation and Acquired Aortic Valve Stenosis Secondary to Infectious Endocarditis in a Goat with Suppurative Mastitis.

A six-year-old female goat was presented to the veterinary teaching hospital of the University of the West Indies with a history of progressive hind-limb paresis lasting two weeks. The doe developed a grade 6/6 holosystolic murmur during hospitalisation. Echocardiography revealed vegetative growths attached to cusps of the mitral and aortic valves. There was an accelerated aortic flow at 2.9 m/s and aortic insufficiency. The aortic vegetation was prolapsing into the left ventricle during diastole, causing it to contact the septal mitral valve leaflet. A diagnosis of mitral and aortic vegetative endocarditis, with a mitral kissing vegetation and mild aortic stenosis, was reached. The patient was placed on broad-spectrum antimicrobials. A short-term follow-up showed no resolution of clinical signs, and the animal eventually died. Post-mortem examination showed severe vegetative, fibrino-necrotic, aortic and mitral valve lesions. The goat also had a severe fibrino-suppurative mastitis. Histopathology confirmed the lesions to be vegetative endocarditis.

Parallel testing of plasma iron and fibrinogen concentrations to detect systemic inflammation in hospitalized horses.

OBJECTIVES: To determine if plasma iron concentration is different between horses with and without systemic inflammation (SI) and to assess the accuracy for the detection of SI by assaying plasma iron and fibrinogen concentrations, individually or combined. To assess the prognostic value of plasma iron concentration and to describe the progression of plasma iron and fibrinogen concentrations during hospital follow-up, and its relation to SI and survival. DESIGN: Prospective observational study evaluating plasma iron and fibrinogen. SETTING: University veterinary teaching hospital. ANIMALS: Equine patients greater than 30 days of age. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Plasma iron and fibrinogen concentration was prospectively determined in hospitalized horses. Horses were classified into 2 groups: SI and non-SI. Horses were also classified according to clinical outcome. A group of control healthy horses was also included. A total of 135 horses were included in the study. Plasma iron concentration was significantly lower and fibrinogen concentration was higher in the SI group. Nonsurvivors had a mean plasma fibrinogen concentration significantly higher than survivors. The combination of plasma iron and fibrinogen has a high degree of specificity, sensitivity, and accuracy for the detection of SI in horses. Follow-up measurements were obtained in 48 horses. Surviving horses normalized plasma iron concentration during follow-up examination whereas nonsurviving horses had persistently low plasma iron concentrations. CONCLUSIONS: Plasma iron concentration alone is an accurate marker of SI in hospitalized horses. Alteration of both plasma iron and fibrinogen concentrations improves the specificity and positive predictive value for diagnosis of SI. Alteration of either one of both increases sensitivity and negative predictive value. Surviving horses normalized plasma iron concentrations during follow-up period. The combination of plasma iron and fibrinogen concentrations may help in the detection of SI. Follow-up of plasma iron concentrations may provide useful prognostic information.