S. Ninokawa1, D. Tatum2, K. Nordham1, S. Taghavi1, C. Guidry1, P. McGrew1, R. Schroll1, C. Harris1, J. Duchesne1 1Tulane University School Of Medicine,Department Of Trauma & Acute Care Surgery,New Orleans, LA, USA 2Our Lady of the Lake Regional Medical Center,Baton Rouge, LA, USA
Introduction:
Patients with severe hemorrhage managed with mass transfusion protocol (MTP) are at risk of post-transfusion citrate-induced hypocalcemia and hyperkalemia. While ionized calcium (iCa) has been shown to be a predictor of mortality in MTP patients, here we evaluate the interaction of potassium (K), ionized calcium (iCa), and the K/iCa ratio as predictors of mortality in patients with severe hemorrhage receiving MTP.
Methods:
This was a retrospective review of adult trauma patients from 2014-2019 who received MTP within one hour of arrival to a Level 1 trauma center. Receiver operating characteristic (ROC) curve analysis was used to assess the predictive capacity of iCa and the K/iCa ratio on mortality. The coordinate points on the ROC curve were used to establish a K/iCa ratio cut-off value by optimizing the Youden index. To identify the effect of K/iCa on survival, Kaplan-Meier (KM) survival analysis and Cox regression models were used.
Results:
Among 531 MTP patients, 146 met inclusion criteria. Patients who expired had higher K/iCa ratios than those who survived (median[IQR]= 5.7[3.8-7.2] vs 3.7[3.1-4.9], p <0.001). In the ROC curve analysis, the area under the curve (AUC) for predicting mortality by K/iCa (AUC=0.72 [95% CI 0.62 – 0.82], p <0.001) was larger than that of iCa alone (0.66 [95% CI 0.56 – 0.76], p <0.01). In the K/iCa ROC curve, an optimal cutoff value of 5.09 was identified, with a sensitivity of 63.2% and specificity of 78.7%. A KM survival curve revealed that high K/iCa ratio was a strong prognostic marker for mortality (p <0.001). Cox regression demonstrated a significant association between K/iCa ratio and mortality (HR 1.15, 95% CI 1.07– 1.23, p <0.001).
Conclusion:
These findings demonstrate that an elevated K/iCa ratio in trauma patients managed with MTP is a better mortality predictor than iCa alone. During early MTP, K levels should be closely monitored in relation to iCa levels. Further validation of this prognostic marker is needed.
