Non invasive CPAP ventilation in a dog with cardiogenic pulmonary oedema.

History and signalment: A 10 years old female Doberman of 40 kg of body weight, was referred to the Veterinary Teaching Hospital for dysorexia and respiratory problems. Diagnostic work: The dog was depressed, with grey mucous membrane, polypneic (respiratory rate > 60 bpm), and heart rate of 123 bpm. At the auscultation no heart murmurs were present but crackles sounds were audible in the thorax. Rectal temperature was 38.3 °C and non-invasive blood pressure was 128, 102 and 110 mm Hg for systolic, diastolic and mean pressure, respectively. A flow-by oxygen therapy started immediately. A serious pulmonary edema, of suspected cardiogenic origin, was revealed by the x-ray. Arterial blood gas analysis showed severe hypoxia: PaO2 53 mm Hg, PaCO2 35 mm Hg, SaO2 86 %, pH 7.45. Hematochemical parameters and electrolytes were within the clinical range. Electrocardiogram showed sporadic PVC. Therapy: Furosemide (4 mg/kg) was administered intravenously and a fluid therapy with NaCl 0.9% initially started. Butorphanol 0.25 mg/kg was given IV to decrease the dog discomfort. Continuous positive airway pressure ventilation (CPAP) via facemask with the Boussignac valve (VygonTM) was administered starting with a pressure of 2.5 cm H2O. A rubber diaphragm was used to fit the mask to the dog muzzle. A catheter was placed in the dorsal pedal artery to make serial blood samples for the blood gas analysis. Non-invasive blood pressure was initially monitored every five minutes with oscillometric technique and the electrocardiographic evaluation was continuously performed. A Foley urinary catheter was placed to evaluate the urinary output. Thirty minutes after the starting of the 2.5 cm H2O CPAP ventilation, an arterial blood gas analysis was performed and the oxygenation still resulted low (PaO2 63 mm Hg). The pressure ventilation was set at 5 cm H2O. In the first 60 minutes the arterial blood gas analysis revealed a PaO2 of 158 mm Hg while in the next 60 minutes it rose to 267 mm Hg. The CPAP was discontinued and oxygen was then administered with a facemask and the blood gas analysis showed a PaO2 of 97 mm Hg. Because of the clinical amelioration of the status, it was decided to perform CPAP only if PaO2 would fall under 90 mm Hg. During the night the oxygen therapy was interrupted and the PaO2 at room air was 85 mm Hg. A blood gas analysis done in the morning demonstrated that the dog oxygenation status was stable (PaO2 104 mm Hg). Echocardiographic examination confirmed a dilated cardiomyopathy and an appropriate therapy was prescribed. After two days the dog was discharged in good clinical conditions, even if the radiography still showed interstitial pulmonary edema signs. The dog died euthanized seven months later. Discussion: This case report showed that the employment of CPAP ventilation via facemask could be effective in increasing the patient oxygenation during the management of the acute pulmonary edema. The procedure was non-invasive and well tolerated by the patient and no alteration of the blood pressure was registered during the treatment.