The assessment of platelet function using multiple electrode aggregometry in practical procedures in anaesthesia

BACKGROUND

Platelets are responsible for primary haemostasis. Patients with suspected platelet dysfunction require prompt clinical assessment when qualifying for emergency surgical procedures. The purpose of this article is to present our experience in platelet function assessment using whole-blood multiple electrode aggregometry (MEA) in various clinical conditions.

CASE REPORTS

Retrospective analysis of three patients with thrombocytopathy associated with normal platelet counts was performed using standard laboratory tests complemented by MEA. In two cases, platelet dysfunction was due to antiplatelet drugs, while in one other case it was caused by chronic kidney disease.

CONCLUSIONS

Anaesthesiologists strive to make the perioperative period as safe as possible. Platelet function assessment should be considered in every patient in whom haemostatic disturbances are suspected. MEA provides support for clinical decision-making, especially in patients who undergo haemodialysis or require antiplatelet therapy, and are in need of emergency surgery.

Multiple electrode aggregometry as a method for platelet function assessment according to the European guidelines

Platelets play an essential role in haemostasis. Assessment of their function is vital for anaesthesiologists evaluating haemostatic potential, especially during emergency operations. The monitoring of platelets function had been implemented into the European recommendations for management of perioperative and posttraumatic bleeding. One of the diagnostic methods described in the recommendations is multiple electrode aggregometry. As antiplatelet therapy becomes more widely used in modern medicine, this method, in contrast to standard laboratory tests, can significantly help to identify patients with drug-induced thrombocytopaty. The aggregometry enables prompt evaluation of the platelets aggregation which is very useful for everyday decision-making in goal-directed hemostatic therapy.

Is Hydroxyethyl Starch Irrelevant to Hemostasis in Patients Undergoing Liver Transplantation?--In vitro Analysis Based on Thromboelastometry

BACKGROUND

Liver transplantation may be associated with severe bleeding that requires intensive fluid management. Aggressive fluid administration could result in hemodilution, triggering dilutional coagulopathy that intensifies bleeding. Colloids are plasma expanders used in daily practice. Fibrinogen, malfunctioning in liver cirrhosis, is the earliest decreasing clotting factor while bleeding. Fibrinogen supplementation is recommended as the first-choice therapy in such cases. Therefore, the influence of hemodilution on fibrin clot formation among patients with liver cirrhosis was analyzed, followed by the assessment of fibrinogen supplementation in clot restitution.

MATERIAL AND METHODS

Blood collected from 22 patients with post-inflammatory liver cirrhosis was diluted up to 30% and 60% with crystalloid (0.9% NaCl) or colloid (6% hydroxyethyl starch 130/0.4), followed by fibrinogen supplementation corresponding to an overall dose of 4 g. The influence of hemodilution on plasma fibrinogen concentration and on thromboelastometry FIBTEM test was analyzed, as well as the influence of fibrinogen supplementation.

RESULTS

Hemodilution lowers fibrinogen concentration and decreases fibrin clot formation. The higher the grade of dilution, the more profound the disturbances observed; 6% hydroxyethyl starch 130/0.4 cause more intense effect on fibrin clot formation than 0.9% NaCl. Fibrinogen supplementation improves fibrin clot formation as assessed in FIBTEM.

CONCLUSIONS

Fibrinogen supplementation among patients with liver cirrhosis might improve fibrin clot formation during hemodilution. Fibrinogen supplementation might by considered as a possible treatment of coagulopathy during liver transplantation, but further clinical studies need to be performed.

The effects of in vitro hemodilution and fibrinogen concentrate substitution on thromboelastometry analysis in patients qualified for liver transplantation - preliminary results

BACKGROUND

Dilutional coagulopathy might cause life-threatening hemorrhages in liver transplantation. Liver insufficiency is usually accompanied by alteration in fibrinogen (Fib) synthesis, which is one of the main clotting factors providing appropriate hemostasis. Intraoperative hemodilution results in further Fib concentration reduction enhancing coagulopathy and blood loss. Exogenous Fib substitution might prevent this.

METHODS

A prospective study with a control group was designed. The study group consists of patients with cirrhosis who qualified for liver transplantation. Inclusion and exclusion criteria were strictly established. The blood collected from participants was diluted up to 30% and 60% with crystalloid (saline) or colloid (hydroxyethyl starch) in 2 parallel series. The first series consisted of diluted blood, the second of diluted blood with Fib concentrate. Thromboelastometry tests were performed on every blood sample. After collecting data from the first 12 participants, we performed a preliminary analysis.

RESULTS

The maximum clot formation (MCF) in the EXTEM test decreased with progressive blood dilution in both study arms. The MCF values were lower than 35 mm in every diluted blood sample of the study group. The recovery of decreased MCF after Fib concentrate substitution was observed in both groups. The improvement in clot formation was also expressed as amplitude of clot firmness in the 10th minute (A10) in the FIBTEM test.

CONCLUSIONS

Clot formation is disturbed more profoundly by hemodilution in cirrhotic patients. Fib concentrate substitution might be effective in the management of dilutional coagulopathy.