Does Rotem-Guided Therapy Influence Postoperative Chest Tube Output in On-pump CABG?

The purpose of this study was to identify the association between ROTEM-guided therapy and chest tube output in patients who have undergone elective on-pump CABG. Introduction: In open heart surgery, there are a variety of ways that coagulation disturbances occur, such as hemodilution of coagulation factors and platelets, a reduction in coagulation factors due to the use of cardiopulmonary bypass the administration of the anticoagulant heparin, and altered temperature. Severe bleeding is frequently associated with open-heart surgery, especially on-pump coronary artery bypass grafting (CABG). Thromboelastometry using rotational thromboelastometry (ROTEM) is a point-of-care testing that can show specific defects in the coagulation process and help guide the way the deficiencies are replaced. ROTEM uses a sample of patients’ blood and forms a clot, creating a graphic and numerical representation of the clotting process. Methodology: This study used a retrospective, quantitative, case-control design at Charleston Area Medical Center in West Virginia. A chart review was conducted on adult patients who underwent elective on-pump CABG from January 1, 2012 to June 1, 2016. A review of medical records was conducted on 200 patients at CAMC Memorial Hospital. The sample was grouped a ROTEM-guided therapy group (n=100) and non-ROTEM-guided therapy group (n=100). Patient characteristics of age, gender, race, and Body Mass Index (BMI) kg/m2 were collected. Clinical characteristics of cardiopulmonary bypass time (CPB) in minutes, number of bypasses, and chest tube output at 1 hour, 2 hours, 4 hours, and 8 hours measured in milliliters (ml) were collected. Means were compared using the Independent t-test for age, BMI, CPB, number of bypasses, chest tube output at 1 hour, at 2 hours, at 4 hours, and at 8 hours. Chi-square test was used to compare gender and race. A multiple step-wise linear regression was used to determine a relationship between chest tube output at 1, at 2, at 4, and at 8 hours with age, gender, race, BMI, CPB, and ROTEM-guided therapy (RGT). Results: There was no statistical significance found between the ROTEM-guided therapy and chest tube output at 1, 2, 4, or 8 hours. The mean age for the total sample was 58.5 years, mean number of bypasses 3.67, and mean BMI was 29.4. Of the 200 patients, 154 (76%) were male, 46 (23%) were female. Statistical significance was found in the RGT group and number of bypasses (p=0.027); and RGT and CPB (p<0.001). A statistically significant association was also found between BMI and chest tube output 1 hour (p=0.001), at 2 hours (p=0.001), at 4 hours (p<0.001), and 8 hours (p<0.001). Discussion: This study found that as BMI increases with patients undergoing on-pump CABG was associated with decreased chest tube output. Though there was longer CPB time and slightly more bypasses conducted on patients who received ROTEM-guided therapy, the amount of chest tube output was not significant different than patients who did not receive ROTEM-guided therapy. The association between the independent variables age, gender, cardiopulmonary bypass time, and number of bypasses with chest tube output at each hour measured was not significant. The literature is conflicting on the efficacy of ROTEM with decreasing chest tube output but supports the findings of increased BMI with decreased chest tube output. Several limitations were identified and discussed. Conclusion: This study revealed there was no difference in chest tube output between the patients who received ROTEM-guided therapy and those who did not receive ROTEM-guided therapy. However, the study did reveal that increasing of BMI may lead to lower intraoperative blood loss.