In vitro assessment of the effect of acidemia on coagulation in dogs

Abstract

Objective: Minimal data are available assessing the effect of acidemia on coagulation in dogs. The objective of this study was to assess the effect of in vitro acidification of canine blood on coagulation as measured via thromboelastography (TEG) and traditional tests of coagulation. We hypothesized that worsening acidemia would lead to progressive impairment on coagulation.

Design: Prospective study.

Setting: University teaching hospital.

Animals: Six client-owned dogs.

Interventions: None.

Measurements and main results: Blood was collected into 3.2% sodium citrate vacutainer tubes. The pH of blood was adjusted from baseline using hydrochloric acid to create weak acidemia and strong acidemia. Coagulation was assessed using TEG, prothrombin time, and activated partial thromboplastin time. Kruskal-Wallis tests with Dunn's post hoc comparison tests were used to compare groups. Strong acidemia samples were significantly more acidic than baseline based on pH (P < 0.0005), HCO₃^- (P < 0.0062), pCO₂ (P < 0.0001), and base excess (P < 0.0001). Using TEG, in vitro acidification of blood caused significant, progressive impairment of maximum amplitude (P = 0.0282) and alpha angle (P = 0.0312). Acidification of blood had no significant effect on prothrombin time (P = 0.345) or activated partial thromboplastin time (P = 0.944).

Conclusions: In vitro acidification of canine whole blood results in hypocoagulability as measured by some TEG variables.

Keywords: acid-base; acidosis; coagulopathy; hypocoagulable; thromboelastography.