Incidence of and risk factors for postoperative pneumonia in dogs anesthetized for diagnosis or treatment of intervertebral disk disease.

OBJECTIVE: To determine incidence of and risk factors for postoperative pneumonia in dogs anesthetized for diagnosis or treatment of intervertebral disk disease (IVDD).
DESIGN: Retrospective case-control study. ANIMALS: 707 dogs that underwent general anesthesia for the diagnosis or treatment of IVDD between 1992 and 1996 or between 2002 and 2006. PROCEDURES: Postoperative pneumonia was diagnosed if compatible clinical signs (cough or hypoxemia) and radiographic abnormalities (alveolar infiltrates) developed within 48 hours after anesthesia. To identify risk factors for postoperative pneumonia, findings for dogs that developed postoperative pneumonia between 2002 and 2006 were compared with findings for a randomly selected control group of unaffected dogs from the same population.
RESULTS: There were no significant differences in age, breed, body weight, sex, location of IVDD, or survival rate between the 2 time periods, but there were significant differences in the use of magnetic resonance imaging, computed tomography, and hemilaminectomy and in the percentage of dogs that developed postoperative pneumonia in the later (4.6%) versus the earlier (0.6%) years. Significant risk factors for postoperative pneumonia included preanesthetic tetraparesis, cervical lesions, undergoing magnetic resonance imaging, undergoing > 1 anesthetic procedure, longer duration of anesthesia, and postanesthetic vomiting or regurgitation. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that at this institution, the incidence of postoperative pneumonia in dogs anesthetized for diagnosis or treatment of IVDD had increased in recent years.