Sonoclot Coagulation Analyzer Research Articles

Evaluation of Platelet Function by Sonoclot Analysis Compared with Other Hemostatic Variables in Cardiac Surgery

Platelet function can be easily measured as time to peak (TP) by Sonoclot Coagulation & Platelet Function Analyzer (Sienco Inc., Morrison, CO) analysis. However a correlation between Sonoclot analysis and platelet aggregation, which is accepted as a test of platelet function, has not been established. In this study, we compared TP and collagen-induced whole blood platelet aggregation in 15 patients undergoing cardiac surgery. Two or three blood samples were randomly obtained from each patient before and after cardiopulmonary bypass (CPB). Sonoclot analysis, collagen-induced whole blood aggregation, and laboratory measurement (including platelet count and coagulation profile) were measured. Seventy-two samples were obtained (35 before CPB and 37 after CPB). TP was correlated with collagen-induced whole blood aggregation (r = -0.652), platelet count (r = -0.671), fibrinogen level (r = -0.598), prothrombin time (r = 0.394), activated partial thromboplastin time (r = 0.486), and use of CPB (r = 0.380). Significant predictors of TP for multiple linear regression modeling were collagen-induced whole blood aggregation, platelet count, and fibrinogen level (r = 0.742). In conclusion, Sonoclot analysis TP predicts approximate platelet function in patients undergoing cardiac surgery. Implications: Approximate platelet function can be easily measured as time to peak by Sonoclot analysis. In this study, time to peak was predicted by platelet count, whole blood platelet aggregation, and fibrinogen level for multiple linear regression modeling. (Anesth Analg 1998;87:1228-33)

Effect of Age, Gender, and Platelet Count on Sonoclot Coagulation Analysis in Patients Undergoing Orthopedic Operations

To assess the relationship between Sonoclot coagulation variables and age, gender, or platelet count in surgical patients without coagulation disorders. This study included 136 patients undergoing orthopedic surgical procedures under spinal or epidural anesthesia. Whole blood was withdrawn preoperatively from each patient, and a Sonoclot analysis was performed within 2 minutes after the sample was obtained. The Sonoclot results were considered investigational and not used in the perioperative management of the patients. Variables from the Sonoclot graphs were analyzed statistically to determine any associations with age, gender, or platelet count. The Sonoclot baseline height was decreased in patients with lower hemoglobin levels, older age, and female gender. The upward slope from baseline to inflection (R1) was increased in female patients and older patients. In comparison with patients who had lower platelet counts, patients with higher platelet counts exhibited a shorter time to inflection, increased upward slope from inflection to peak (R2), shorter time to peak, increased downward slope from peak to plateau (R3), decreased time to plateau, and lower plateau height (P < or = 0.01 for all relationships). Sonoclot coagulation analysis reliably evaluates platelet count as an indicator of platelet function. Controlled studies are needed to examine the clinical usefulness of Sonoclot coagulation analysis in the diagnosis and treatment of perioperative coagulopathies and hemorrhagic complications.

A.322 Sonoclot coagulation analysis as a rapid guideline in the HELLP syndrome

A.322 Sonoclot coagulation analysis as a rapid guideline in the HELLP syndrome

Persistent hypercoagulation associated with heterotopic ossification in patients with spinal cord injury long after injury has occurred.

Three patients are presented with traumatic spinal cord injury (SCI) complicated by acute heterotopic ossification (HO), and concurrent deep vein thrombosis 15 months, 18 months and 22 years after SCI, accompanied by persistent hypercoagulation. The diagnosis of HO preceded deep vein thrombosis in all three patients. All were treated with etidronate disodium and therapeutic heparin followed by oral anticoagulation. As these patients were not acutely injured, the questions arose as to what predisposed them to deep vein thrombosis and when was the appropriate time to discontinue anticoagulation. Over a course of 3 years following deep vein thrombosis, these patients were monitored for evidence of hypercoagulation by D-dimer assay, plasma fibrinogen estimation, and rate of whole blood clotting by Sonoclot coagulation analyzer. The activity of acute HO was assessed by three-phase bone scan. A steady state of hypercoagulation, reflected by an increase in all three parameters, ran parallel to the extent of acute HO for the entire observation period. Moreover, hypercoagulation was persistently greater during increased acute HO activity even when the warfarin-induced prothrombin time ratio was 1.2-1.5. In addition, as acute heterotopic ossification activity decreased, the test values returned to near normal during warfarin therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of Methylprednisolone on Intravascular Coagulation and Edema Formation Induced by Venous Occlusion

Cause and effect relations between Intravascular coagulation and increased vascular endothelial permeability have recently been recognized. The purpose of this study was to investigate the effect of high dose methylprednisolone on tissue edema formation and coagulation in canine legs subjected to venous occlusion. Eight mongrel dogs received 30mg/kg methylprednisolone administration intravenously. Eight additional days received normal saline as controls. Hind leg venous pressure was raised to 75mmHg continuously for 5 hours by a tourniquet around the thigh. Venous blood was sampled before tourniquet inflation, six times during tourniquet inflation, and 60 min after tourniquet ination. The sample blood was used for measurement of Sonoclot coagulation analysis, prothrombin time, and activated partial thromboplastin time. At each time of venous blood sampling, circumferences of 3 points of the distal part of the hind leg were measured to assess edema. Coagulation studies indicated initial hypercoagulability, and later hypocoagulability during venous occlusion in the control group. In the methylprednisolone-treated group, coagulation parameters remained unchanged throughout the study. Percent increases in circumferences as indices of edema formation were significantly less in the methylprednisolone-treated group than in the control group. The results suggest that inhibitory action of methylprednisolone on activation of the coagulation system secondary to venous occlusion may be a key factor in maintaining the integrity of endothelial permeability, resulting in less edema formation.

Ｓｏｎｏｃｌｏｔ Ｃｏａｇｕｌａｔｉｏｎ Ａｎａｌｙｚｅｒを用いた凝血学的検査の臨床 Ｉ 正常値と基礎的検討

Basic study on normal and abnormal tracings of sonoclot coagulation analyzer (SCA) was performed. Beginning of fibrinogenesis can be detected earlier by SCA than by thromboelastgram. Recalcified citrated whole blood or plasma can be used. Reproductibility of the tracing was good. Not only the concentrations of hemostatic factors and platelet counts but also Ca2+ concentration, the concentrations of F XII activators, hematocrit value affect the tracing. Normal value of the onset time of Japanese adults, which is said to show the interval between the initiation and the beginning of fibrinogenesis was male: X±2SD=124.5±44.2sec, female: X±2SD=96.6±37sec. The sexual difference is statistically significant (p<0.001). SCA is considered to be applicable to clinical investigation of hemostasis.

Evaluation of a new dynamic viscometer for measuring the viscosity of whole blood and plasma.

We evaluated a new type of dynamic viscometer, the Sonoclot Coagulation Analyzer, for use in measuring the viscosity of whole-blood and plasma. Such information can be useful in monitoring patients with hyperviscosity syndromes, e.g., from multiple myeloma. A vibrating Teflon or plastic probe continuously measures dynamic viscosity. The instrument can be calibrated to measure a range of viscosities from 0.69 to 23 cP (mN X s X m-2) or more. The coefficient of variation at 0.69 cP was 3-4% for measurements with the Teflon probe, 7-9% with the plastic probe. Viscosity measured at 37 degrees C for plasma and whole-blood samples from 20 normal patients was 1.22 (SD 0.05) cP and 3.63 (SD 0.52) cP, respectively. Dynamic viscosity measured in blood samples from a single source, with contrived hematocrits ranging from 0 to 89%, increased exponentially as a function of hematocrit, confirming previous studies. Overall, we found this instrument simple and quick to operate, producing accurate, precise viscosity measurements over at least a 40-fold range of viscosity.