The effects of protamine sulfate on clot formation time and clot strength thromboelastography variables for canine blood samples.

摘要

Objective - To determine the effects of protamine sulfate on clot formation time and clot strength thromboelastography variables for canine whole blood samples. Animals - Blood samples obtained from 11 healthy dogs. Procedures - Blood samples were collected from jugular veins of dogs into syringes with 3.2% sodium citrate (blood to citrate ratio, 9:1). Blood samples were divided into aliquots, and protamine sulfate was added to various concentrations (0 [control], 22, 44, and 66 micro g/mL). Prepared samples were activated with kaolin (n=8) or not activated (8), CaCl₂ was added, and thromboelastography was performed. Reaction time (R), clot formation time (K), rate of clot formation ( alpha angle), and maximum amplitude (MA) were measured. Results - For kaolin-activated and nonactivated blood samples, protamine (66 micro g/mL) significantly increased R and K and decreased alpha angle and MA, compared with values for control samples. Also, protamine (44 micro g/mL) decreased MA in nonactivated blood samples and increased K and decreased alpha angle in kaolin-activated samples, compared with values for control samples. Conclusions and Clinical Relevance - Results indicated protamine prolonged clot formation time and decreased overall clot strength in a dose-dependent manner; such effects may contribute to a hypocoagulable state in dogs. Kaolin-activated and nonactivated blood samples were appropriate for measurement of the effects of protamine on coagulation. Administration of protamine to reverse the effects of heparin should be performed with caution.