Thromboelastographic evaluation after cardiac surgery optimizes transfusion requirements in the intensive care unit: a single-center retrospective cohort study using an inverse probability weighting method

Abstract

Objective: There are no reports from Japan showing the effects of using the thromboelastography algorithm on transfusion requirements after Intensive Care Unit (ICU) admission, and post-implementation knowledge regarding the thromboelastography algorithm under the Japanese healthcare system is insufficient. Therefore, this study aimed to clarify the effect of the TEG6s thromboelastography algorithm on transfusion requirements for patients in the ICU after cardiac surgery.

Methods: We retrospectively compared the requirements for blood transfusion up to 24 h after ICU admission using the thromboelastography algorithm (January 2021 to April 2022) (thromboelastography group; n = 201) and specialist consultation with surgeons and anesthesiologists (January 2018 to December 2020) (non-thromboelastography group; n = 494).

Results: There were no significant between-group differences in terms of age, height, weight, body mass index, operative procedure, duration of surgery or cardiopulmonary bypass, body temperature, or urine volume during surgical intervention. Moreover, there was no significant between-group difference in the amount of drainage at 24 h after ICU admission. However, crystalloid and urine volumes were significantly higher in the thromboelastography group than in the non-thromboelastography group. Additionally, fresh-frozen plasma (FFP) transfusion volumes were significantly lower in the thromboelastography group. However, there were no significant between-group differences in red blood cell count or platelet transfusion volume. After variable adjustment, the amount of FFP used from the operating room to 24 h after ICU admission was significantly reduced in the thromboelastography group.

Conclusions: The thromboelastography algorithm optimized transfusion requirements at 24 h after admission to the ICU following cardiac surgery.

Keywords: Cardiac surgery; Intensive care unit; Patient blood management; Thromboelastography; Transfusion.

Fig. 1

TEG6s protocol in the intensive care unit. PB, cardiopulmonary bypass; CBC, complete blood count including red blood cell and platelet counts; PM, Platelet Mapping by TEG6s [15]; FibCare, a device that can rapidly measure the fibrinogen levels in the operating room [10]; ACT, activated coagulation time; R, reaction time of TEG6s; MA, maximum amplitude of TEG6s; FFP, fresh-frozen plasma; PC, platelet concentrate; Cryo, cryoprecipitate. The following were the TEG6s measurement items: CK-R, CKH-R, CRT-MA, and CFF-MA. For the values included in the algorithm, we consulted the academic literature and adopted commonly used values [–14]

Fig. 2

Flow diagram. During the study period, 754 patients underwent cardiac surgery with cardiopulmonary bypass and 59 patients met the exclusion criteria; thus, 695 patients were included. In total, 494 and 201 were classified in the non-TEG and TEG groups, respectively. All classified cases were included in the analysis as there were no omissions due to insufficient data. TEG, thromboelastography

Fig. 3

Forest plot according to multivariable regression analysis. To examine changes in the blood transfusion volume before and after the introduction of the TEG6s algorithm, multivariable regression analysis was performed, with blood transfusion volume as the dependent variable, and “before and after the introduction of the algorithm” as the independent variable, adjusting for age, sex, body mass index, operative time, ventilation time, and blood loss. “Before” referred to the non-TEG group, whereas “after” referred to the TEG group. TEG, thromboelastography; RCC, red cell concentrate; FFP, fresh-frozen plasma; PC, platelet concentrate

Fig. 4

Forest plot according to propensity scores and the inverse probability weighting method. To examine changes in the blood transfusion volume before and after the introduction of the TEG6s algorithm, propensity scores and the inverse probability weighting method was performed, with blood transfusion volume as the dependent variable, and “before and after the introduction of the algorithm” as the independent variable, adjusting for age, sex, body mass index, operative time, ventilation time, and blood loss. “Before” referred to the non-TEG group, whereas “after” referred to the TEG group. TEG, thromboelastography; RCC, red cell concentrate; FFP, fresh-frozen plasma; PC, platelet concentrate