Summary – A Prospective, Randomized Clinical Trial of Efficacy in Coagulopathic Cardiac Surgery Patients

Link to the paper: https://www.ncbi.nlm.nih.gov/pubmed/22914710

Introduction

It’s been found that the usage of allogenic blood products are independently associated with increased mortality and adverse events. In literature, it states that an accurate diagnosis of underlying hemostatic pathology is important and so having an algorithm driven hemostatic therapy is important and found to be better than clinical judgement. Some studies show point of care testing with viscoelastic analyses of clot formation and dissolution reduce transfusion rates of allogenic blood products, and so the goal of the study was to compare therapy algorithms based on point-of-care (POC) vs algorithms based on conventional laboratory testing. The primary outcome analyzed was the amount of perioperative transfused units of packed red cells.

Methods and Materials

The study was a prospective, randomized parallel-group single center study that was carried out in Germany. The participants were 18 or older and had an elective, complex cardiothoracic surgery which could mean combined coronary artery bypass graft and valve surgery, double/triple valve procedure, or aortic surgery. These procedures were done with a cardiopulmonary bypass (CPB) and pregnant patients were excluded.

CPB is a form of extracorporeal circulation where the patient’s blood is rerouted from the heart and lungs to the outside of the body. It takes over the function of the lung and heart which include circulation of blood, oxygenation, and ventilation.

After they found the people who fit the initial set of requirements which was step 1, they had a second step. They required that patients enrolled in the study must be those who had a heparin reversal following CPB and at least 1 of 2 criteria. The first criteria being a diffuse bleeding from capillary beds at wound surfaces requiring hemostatic therapy judged by the surgeon and anesthesiologist OR intraoperative or postoperative blood loss exceeding 250ml/h. Post operative meaning during the first 24 hours after the surgery.  After enrollmentb patients were randomly placed into a POC group and conventional group.

Both groups received conventional coagulation tests for comparison, but physicians from the POC testing group were blinded to the conventional laboratory test results. The point of care testing that were used was thromboelastometry also known as ROTEM and aggregometry for platelet function.

TEG/ROTEM was created by Hellmut Hartert in 1948 to demonstrate hemostatic function for whole blood samples. It helped guide blood component therapy in the Vietnam War and in the 1980’s it was used in liver transplant surgery to improve efficiency and later cardiac surgery patients in the 90’s and trauma patients.

The conventional lab testing and POC hemostatic therapy algorithm analysis was based on evidence based hemostatic therapy management. The POC based algorithm was based on the one used in some university hospitals in Germany.

Laboratory values between the two groups were for the most part were not significantly different. Fibrinogen and lactate were slightly different but otherwise there weren’t any significant differences between the two groups.

Results/Discussion

The usage of packed red blood cells, fresh frozen plasma, and platelets were significantly different between treatment groups. There were significant cost differences between the two groups as well. The POC group had better mortality and outcomes although the sample size was too low to have a significant statistical difference between the two populations. Problems with the study include it being single centered, low sample size, unknown algorithm used, etc. The paper is still significant in the fact it shows improved red blood cell usage where ROTEM and aggregometry guides patient blood management.