C. R. Reed1, C. McCall2, C. Vatsaas1, S. Agarwal1, E. T. Tracy1 2Duke University Medical Center,Department Of Pathology,Durham, NC, USA 1Duke University Medical Center,Department Of Surgery,Durham, NC, USA
Introduction:
Trauma-induced coagulopathy (TIC) is a significant cause of morbidity in trauma patients. In healthy individuals, blood maintains a pH of 7.35-7.45 but traumatic injury can lead to acidosis and subsequent TIC. Rotational thromboelastometry (ROTEM) is a useful tool in rapidly identifying mechanisms of coagulopathy. However, the effects of traumatic acidosis on ROTEM have not been studied in vivo. We aim to describe the effects of acidemia on ROTEM coagulation time (CT), maximum clot firmness (MCF), and other ROTEM results in trauma patients.
Methods:
We queried our Level 1 trauma center trauma database for all level 1 and 2 trauma activations from 2014-2017. Mortality, demographics, injury data, and emergency department (ED) laboratory studies were evaluated. Patients with arterial blood gas and one or more ROTEM values were included. Acidemia was defined as pH < 7.10 given previous evidence of TIC at this threshold. ROTEM extrinsic (EXTEM) CT and MCF; intrinsic (INTEM) CT and MCF; and fibrin (FIBTEM) MCF were all treated as continuous numerical variables. Non-parametric tests were used to compare continuous and chi-squared test was used to compare categorical variables between the acidemic and non-acidemic groups.
Results:
There were 121 EXTEM, 115 FIBTEM, and 53 INTEM tests performed on patients with complete records. The median age among these patients was 33 (interquartile range [IQR] 35), with an overall mortality of 22%. The median injury severity score was 25 (IQR 19), and 44% of injuries were penetrating. The median initial arterial pH among these patients was 7.24 (0.165), and 21 (17%) were severely acidemic with pH < 7.10. Acidemic patients were more likely to be coagulopathic based on conventional coagulation studies, although only PTT’s difference was statistically significant (PTT p < 0.001 and INR p = 0.056).
Utilizing ROTEM data, EXTEM and INTEM both had significantly reduced MCF values among acidemic patients compared to those without acidemia (p < 0.05 in both cases). However, there were no statistically significant difference in FIBTEM MCF and the EXTEM and INTEM CT based on acidemia (p > 0.05).
Conclusion:
In our study of 121 severely injured patients, we found a significant association between acidemia and crucial elements of their ROTEM coagulation profiles. Given the decreased EXTEM and INTEM MCF with a normal FIBTEM MCF, we suggest that platelet dysfunction is present in acidemia. This effect on TIC appears to be independent of fibrin and coagulation proteases in the development of coagulopathy. Our findings offer further insight into the complex relationships among acid-base hemostasis and coagulation after traumatic injury.
