Continuous positive airway pressure administered via face mask in tranquilized dogs.

Abstract

OBJECTIVE: To evaluate the tolerance of a continuous positive airway pressure (CPAP) mask in tranquilized dogs and compare PaO&#x2082; in arterial blood in dogs receiving oxygen with a regular face mask or CPAP mask set to maintain a pressure of 2.5 or 5 cm H&#x2082;O. DESIGN: Prospective, randomized clinical study. SETTING: University teaching hospital. ANIMALS: Sixteen client-owned dogs without evidence of cardiopulmonary disease were studied. INTERVENTIONS: Eight animals were randomly assigned to each of 2 treatment groups: group A received 2.5 cm H&#x2082;O CPAP and group B received 5 cm H&#x2082;O CPAP after first receiving oxygen (5 L/min) by a regular face mask. Animals were tranquilized with acepromazine 0.05 mg/kg, i.v. and morphine 0.2 mg/kg, i.m.. An arterial catheter was then placed to facilitate blood sampling for pHa, PaO&#x2082;, and PaCO&#x2082; determinations before and after treatments. Direct mean arterial pressure, heart rate, respiratory rate, and temperature were also recorded after each treatment. MEASUREMENTS AND MAIN RESULTS: CPAP administration was well tolerated by all animals. The mean arterial pressure, heart rate, respiratory rate, temperature, PaCO&#x2082;, and pHa, did not differ at any time point between groups. Differences were seen in oxygenation; in group A, PaO&#x2082; significantly increased from a mean of 288.3 &#xb1; 47.5 mm Hg with a standard mask to a mean of 390.3 &#xb1; 65.5 mm Hg with the CPAP mask and in group B, PaO&#x2082; increased similarly from 325.0 &#xb1; 70.5 to 425.2 &#xb1; 63.4 mm Hg (P<0.05); no differences were detected between the 2 CPAP treatments. CONCLUSIONS: In healthy tranquilized dogs noninvasive CPAP is well tolerated and increases PaO&#x2082; above values obtained when using a regular face mask.