title: Use of pericardial fluid pH to distinguish between idiopathic and neoplastic effusions.
abstract: Pericardial effusion (PE) resulting from neoplasia usually is associated with a poor prognosis, whereas idiopathic PE frequently has a good prognosis. This study examined the utility of pH measurement to distinguish between these 2 etiologies. Dogs were classified as having idiopathic PE (n = 12) if pericarditis was diagnosed on histopathology (n = 4) or if no historical, physical, or echocardiographic evidence of recurrent PE was present for at least 6 months after pericardiocentesis (n = 8). Dogs were classified as having neoplastic PE (n = 25) if pericardial or myocardial neoplasia was detected on histopathology (n = 11) or a discrete mass associated with the right atrium, right ventricle, or the aorta was visualized on echocardiography (n = 14). Samples of PE were centrifuged and the supernatant pH was measured with a portable pH meter. The lowest pH (6.40) was found in a dog with idiopathic PE and the highest pH (7.85) was found in a dog with neoplastic PE. However, data from the 2 groups overlapped in 33 out of 37 (89%) instances, and median pH from the idiopathic and neoplastic groups was not significantly different (7.40 and 7.47, respectively; P = 0.28; difference in medians = -0.7; 95% CI, -0.26-0.06). Because of the degree of overlap, our data provide little justification for the use of pH measurement as a diagnostic test in cases of PE.
authors.affiliation: Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA.
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Fine
authors.forename: Anthony H
authors.initials: AH
authors.lastname: Tobias
authors.forename: Kristin A
authors.initials: KA
authors.lastname: Jacob
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology*; D004285:Dogs; D004452:Echocardiography; D005260:Female; D006338:Heart Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000662:veterinary*; D006394:Hemangiosarcoma / Q000150:complications / Q000000981:diagnostic imaging / Q000662:veterinary; D006863:Hydrogen-Ion Concentration; D008228:Lymphoma, Non-Hodgkin / Q000150:complications / Q000000981:diagnostic imaging / Q000662:veterinary; D008297:Male; D008654:Mesothelioma / Q000150:complications / Q000000981:diagnostic imaging / Q000662:veterinary; D008910:Minnesota / Q000453:epidemiology; D010490:Pericardial Effusion / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D011237:Predictive Value of Tests; D013964:Thyroid Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000662:veterinary