Impact of general anesthesia on rotational thromboelastometry (ROTEM) parameters and standard plasmatic coagulation tests in healthy Beagle dogs

Abstract

ObjectiveTo assess the influence of general anesthesia on rotational thromboelastometry (ROTEM) and standard coagulation testing in healthy dogs Study designProspective experimental study Animals10 healthy Beagle dogs MethodsDogs were administered methadone (0.2 mg/kg) intramuscularly. Anesthesia was co-induced intravenously 30 min later with midazolam (0.1 mg/kg) and propofol to effect, and maintained with sevoflurane. Crystalloids were administered at 5 ml/kg/h. Blood was sampled by direct venipuncture before induction (T0) and 3.5 h later (T3.5) and ROTEM parameters (ExTEM, InTEM, FibTEM, ApTEM), standard plasmatic coagulation tests (prothrombin time [PT], activated partial thromboplastin time [aPTT], fibrinogen concentration), hematology, ionized calcium, triglycerides, pH, lactate and body temperature were compared over time with Students t - test or Wilcoxon matched pairs signed-rank tests. ResultsThe following variables dropped significantly between T0 and T3.5: body temperature (p < 0.0001), hematocrit (p < 0.0001), platelet count (p < 0.01), pH (p < 0.01), triglycerides (p < 0.01), fibrinogen concentration (p < 0.01), ExTEM, FibTEM (p < 0.01) and ApTEM (p < 0.05) clotting times. Lactate concentration (p < 0.01), aPTT (p < 0.05) and FibTEM maximum clot firmness increased (p < 0.05). No changes were noted in ionized calcium, PT and InTEM values. Conclusion and clinical relevanceGeneral anesthesia with concurrent hemodilution and hypothermia induced significant but clinically irrelevant changes in coagulation variables measured at 37 °Celsius. Blood samples from anaesthetized animals can be used for determination of coagulation status in dogs.