Investigation of focused cardiac ultrasound in the emergency room for differentiation of respiratory and cardiac causes of respiratory distress in dogs.

OBJECTIVE: To determine whether focused cardiac ultrasound (FOCUS) performed by emergency and critical care (ECC) specialists or residents in training improves differentiation of cardiac (C) versus non-cardiac (NC) causes of respiratory distress in dogs compared to medical history and physical examination alone. DESIGN: Prospective cohort study (May 2014 to February 2016). SETTING: University hospital. ANIMALS: Thirty-eight dogs presenting with respiratory distress. INTERVENTIONS: FOCUS. MEASUREMENTS AND MAIN RESULTS: Medical history, physical examination, and FOCUS were obtained at presentation. Emergency and critical care clinicians, blinded to any radiographic or echocardiographic data, categorized each patient (C vs NC) before and after FOCUS. Thoracic radiography (within 3 h) and echocardiography (within 24 h) were performed. Percent agreement was calculated against a reference diagnosis that relied on agreement of a board-certified cardiologist and ECC specialist with access to all diagnostic test results. Reference diagnosis included 22 dogs with cardiac and 13 dogs with noncardiac causes of respiratory distress. In 3 dogs a reference diagnosis was not established. Prior to FOCUS, positive and negative percent agreement to detect cardiac causes was 90.9% (95% CI, 70.8-98.9) and 53.9% (25.1-80.8), respectively. Overall agreement occurred in 27 of 35 dogs (77.1%). Two C and 6 NC cases were incorrectly categorized. Following FOCUS, positive and negative percent agreement to detect cardiac causes was 95.5% (77.2-99.9) and 69.2% (38.6-90.9), respectively. Overall agreement occurred in 30 of 35 dogs (85.7%). Three dogs with discrepant pre-FOCUS diagnoses were correctly re-categorized post-FOCUS. One C and 4 NC cases remained incorrectly categorized. No correctly categorized dogs were incorrectly re-categorized following FOCUS. The proportions of dogs correctly classified pre- versus post-FOCUS were not significantly different (P = 0.25). CONCLUSIONS: FOCUS did not significantly improve differentiation of C vs NC causes of respiratory distress compared to medical history and physical examination alone.

Retrospective evaluation of and risk factor analysis for presumed fluid overload in cats with urethral obstruction: 11 cases (2002-2012).

OBJECTIVE: To describe patient characteristics, treatment, and outcome in male cats with urethral obstruction (UO) and fluid overload (FO), and to determine risk factors for the development of FO. DESIGN: Retrospective case-control study from 2002-2012. ANIMALS: Eleven client-owned cats with UO that developed respiratory distress secondary to suspected FO and 51 control cats with UO without FO. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Medical records of cats with UO and FO were identified. FO was defined as the development of respiratory distress secondary to pleural effusion or pulmonary edema while receiving IV fluids. To identify risk factors for FO, variables for cats that developed FO were compared with variables from a randomly selected control group of unaffected UO cats during the same time period. Variables analyzed included patient signalment, previous medical history, serum biochemical data, respiratory rate, cardiac auscultation abnormalities, admission systolic blood pressure, intravenous fluid administration, thoracic imaging, treatment, duration and cost of hospitalization, and outcome. Echocardiogram identified heart disease in 5/6 cats with FO. Cost (2.9 times as much) and median duration of hospitalization (4.1 vs 1.8 days) were significantly greater in cats with FO. Cats with FO were more likely to have received a fluid bolus (odds ratio [OR]: 5.1; 95% confidence interval [CI]: 1.3, 20, P = 0.014), developed a heart murmur (OR: 4.5; 95% CI, 1.1-18, P = 0.028) or a gallop sound (OR: 75; 95% CI, 8.1-694, P < 0.0001). CONCLUSIONS: FO is a possible complication of the treatment of UO. The administration of a fluid bolus on presentation, and the development of a heart murmur or gallop sound during treatment were the most clinically useful risk factors identified. The development of FO is associated with significant increases in both the cost and length of hospitalization, but was not associated with increased mortality.

Development of dialysis disequilibrium-like clinical signs during postobstructive management of feline urethral obstruction.

OBJECTIVE: To describe the clinical features, treatment, and outcome of a cat with acute neurologic signs subsequent to relief of urethral obstruction and rapid resolution of severe azotemia, suggesting a process similar to dialysis disequilibrium syndrome. CASE SUMMARY: A male castrated domestic short-hair cat was presented for weakness and dull mentation. Initial physical examination was consistent with urethral obstruction and laboratory data demonstrated severe azotemia, hyperkalemia, and acidemia. Interventions for hyperkalemia and urethral catheterization were performed without complication. The patient demonstrated a marked postobstructive diuresis and 7 hours after presentation suffered a grand mal seizure and was neurologically inappropriate. These changes corresponded with marked decreases in blood urea nitrogen (from 89.25 mmol/L to 19.99 mmol/L [250 mg/dL to 56 mg/dL]) and calculated serum osmolality (429 mOsm/kg to 359 mOsm/kg) from initial presentation without other apparent cause for seizure activity. The patient was treated with hypertonic saline (bolus and continuous infusion) for presumed osmotic injury (dialysis disequilibrium-like clinical signs) along with other supportive care. All neurologic signs resolved within 48 hours, the urinary catheter was removed, and the patient was discharged after 24 hours of observation of spontaneous urination. NEW OR UNIQUE INFORMATION PROVIDED: Dialysis disequilibrium syndrome has been documented in small animals, but similar signs have not been reported as a sequelae of treatment of feline urethral obstruction. Urethral obstruction is a common emergency and practitioners should be aware of this potential complication as a cause of delayed neurologic recovery or seizures in the postobstructive period.