Polycythemia in dogs with chronic hypoxic pulmonary disease

• Published in: Journal of veterinary internal medicine Vol. 36; no. 4; pp. 1202 - 1210
• Main Authors: Holopainen, Saila, Laurila, Henna P., Lappalainen, Anu K., Rajamäki, Minna M., Viitanen, Sanna J.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.07.2022; Wiley
• Subjects: Biochemistry; Blood & organ donations; Bronchoscopy; Cellular biology; Chronic obstructive pulmonary disease; Creatinine; dog; Erythrocytes; erythrocytosis; Gases; Hematology; Hemoglobin; Histopathology; hypoxemia; Hypoxia; Lavage; Lung diseases; Patients; pulmonary; Pulmonary fibrosis; Regression analysis; SMALL ANIMAL; Software; Tomography; Ultrasonic imaging; Variables; Variance analysis; Germany; Finland
• ISSN: 0891-6640; 1939-1676
• DOI: 10.1111/jvim.16466

Background Prolonged tissue hypoxia caused by chronic pulmonary disease is commonly regarded as an important mechanism in the development of secondary polycythemia, but little clinical data are available to support this hypothesis. Objective To study the prevalence and severity of erythrocytosis accompanying chronic hypoxic pulmonary disease in dogs. Animals Forty‐seven dogs with hypoxic chronic pulmonary disease, 27 dogs with nonhypoxic chronic pulmonary disease, and 60 healthy controls. Methods Dogs with chronic pulmonary disease and chronic hypoxemia (partial pressure of arterial oxygen [PaO2] < 80 mm Hg on at least 2 arterial blood gas measurements a minimum of 1 month apart) were identified retrospectively from patient records. Association between arterial oxygen and red blood cell parameters was analyzed using Pearson's correlation coefficients and multivariable linear regression analysis. Results Red blood cell parameters measured at the end of the hypoxemia period were within the laboratory reference range in most dogs. In chronically hypoxemic dogs, hematocrit (Hct) was increased in 4/47 (8.5%; 95% confidence interval [CI], 0‐17) dogs, erythrocyte count (Erytr) was increased in 12/47 (26%; 95%CI, 13‐38) dogs and hemoglobin concentration (Hb) was increased in 3/47 (6.4%; 95%CI, 0‐14) dogs. No marked polycythemia (Hct ≥65%) was noted in any of the dogs. Red blood cell parameters were not associated with the severity of hypoxemia (correlation to PaO2: Erytr, r = −.14; Hb, r = −.21; Hct, r = −.14; P > .05 for all). Conclusions and Clinical Importance Polycythemia is uncommon, and usually mild if present, in dogs with chronic hypoxia caused by pulmonary disease.