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Diagnosis and treatment of feline rhinitis, like canine rhinitis, can be a frustrating experience for the veterinary practitioner. Having sound knowledge of the possible etiologies involved and using a systematic diagnostic approach makes the workup of these challenging cases much easier. Selection of appropriate therapy based on a definitive diagnosis makes treatment rewarding. This article discusses the pathogenesis and treatment of a variety of causes of feline rhinitis.

Summary The usefulness of venous blood in determining the acid-base status of seriously ill animals has not been investigated. The purpose of this study was to determine whether a useful relationship exists between the acid-base parameters of central venous and arterial blood in ill dogs. Paired arterial and venous blood samples were obtained from 46 dogs seen in the Critical Care Unit of the Veterinary Teaching Hospital of Colorado State University irregardless of their hemodynamic status. Cardiopulmonary arrest patients were not included in the study. Results of this study indicate venous blood samples can be used in the assessment of acid-base status. Statistical significance was seen in comparing arterial versus venous pH (P < 0.001), PCO2 (P < 0.001), and bicarbonate (P < 0.001). Linear regression equations will allow one to predict arterial values from venous samples.

Summary Serum magnesium (Mg) is an infrequnetly measured electrolyte in small animal patients. Currently, little is known about the prevalence and significance of abnormalities in serum Mg in animals. Therefore, a prospective study was performed to examine the incidence and clinical implications of abnormalities in serum Mg levels in critically ill dogs. Serum Mg and other electrolytes were measured in 93 normal dogs housed at the Purina Pet Care Center and in 48 ill dogs admitted to a small animal critical care unit. The normal reference range for canine serum Mg was determined to be 1.89 – 2.51 mg/dl. Based on this range, 54% of the critically ill dogs were hypomagnesemic ( 2.51 mg/dl). Of the electrolytes measured in these patients, serum Mg had the highest prevalence of abnormal values. Hypomagnesemic patients had a significantly higher incidence of concurrent hypokalemia and hyponatremia (p < 0.05), as well as a longer length of hospitalization (p < 0.05) than their normomagnesemic counterparts. Hypermagnesemic patients were 2.6 times more likely not to survive their illness when compared to patients with normal serum Mg levels. Abnormalities in serum Mg appear to be common in critically ill dogs. These patients commonly have other concurrent electrolyte abnormalities. Since serum Mg is not routinely measured, the presence of hypokalemia or hyponatremia should alert the clinician to the possibility of coexisting hypomagnesemia. The clinical implications of hypomagnesemia and hypermagnesemia in ill dogs appear to involve prolonged hospitalization and increased mortality, respectively: however, the exact etiology remains undetermined.

Summary Over the past several decades, recognition of acute respiratory failure as the cause of death in patients suffering from various clinical conditions has prompted aggressiv investigation into the area of respiratory physiology and supportive respiratory care. With the evolution of emergency medicine and critical care services in both human and veterinary medicine, many patients previously considered unsalvageable due to the severity of their underlying disease are now being resuscitated and successfully supported, creating a new population of critically ill patients. Where only a decade ago these patients would have succumbed to their underlying disease, they now survive long enough to manifest the complications of shock and tissue injury in the form of acute respiratory failure. Investigation into the pathophysiology and treatment of this acute respiratory distress syndrom (ARDS) has facilitated increased clinical application of respiratory theerapy and machanical ventilation.1 The purpose of this paper is to provide a basic review of respiratory mechanics and the pathophysiology of hypoxemia as they relate to airway pressure therapy in veterinary patients and to review the use of airway pressure therapy in veterinary patients This paper is divided into two parts; part I reviews respiratory mechanics and hypoxemia as they apply to respiratory therapy, while part II deals specifically with airway pressure therapy andits use in clinical cases.

Summary With respiratory therapy in critically ill veterinary patients becoming more commonplace, a consistent Indicator of pulmonary function status is necessary. Although calculation of the pulmonary shunt fraction correlates well with the degree of pulmonary dysfunction, lts detetmination requires placement of a pulmonary arterial catheter, an invasive procedure that may not be practical in many clinical situations. Using Information obtained from the atterial blood gas, many other oxygen-tension derived Indices have been suggested as noninvasive measurements of the efficiency of pulmonary gas exchange, lncluding the alveoiar-arterial oxygen tension difference, the ratio of arterial to alveolar oxygen tension, the ratio of arterial to inspired oxygen tension, and the ratio of alveolar-arterial gradient to arterial oxygen tension. A total of 427 blood gas values from 195 different patients were evaluated. A loglstic regression model using a stepwise algorithm was constructed to assess potential multicollinearity and interaction between factors. The only factors that contributed significantly to the model predictive of survival were age (p < 0.015), base excess (p < 0.029), and the alveolar-arterial oxygen tension difference (p < 0.014).

Unless a systematic approach is used, evaluation of a patient with rhinitis can be frustrating to the veterinary practitioner. A complete differential list for canine rhinitis should include infectious, inflammatory, neoplastic, and traumatic causes. Other causes of rhinitis include dental disease, parasitic infestation, and ciliary dyskinesia. Diagnostic techniques that should be considered when evaluating a patient with rhinitis include obtaining a complete history, performing a thorough physical and oral examination, evaluating the patient's coagulation abilities, cytology and culture of exudate, nasal radiographs, and rhinoscopy. This article describes the pathogenesis and treatment of the various causes of canine rhinitis.