Outcomes of Empiric Calcium Administration with Prehospital Blood Product Administration

Objective

Hypocalcemia in critically ill patients has been previously shown to lead to higher transfusion needs and increased mortality. The purpose of this study was to evaluate if empiric prehospital calcium administration with concomitant blood product delivery in patients with hemorrhagic shock, improved initial in hospital ionized calcium, reduced coagulopathy, reduced blood product administration and improved 24 hour survival.

Methods

Our study was a convenience sample, retrospective chart review over a six year period analyzing clinical outcomes of patients pre and post protocol initiation, of empiric calcium administration with concomitant administration of blood products during aeromedical transport in a hospital based critical care transport program. T-test, Wilcoxon ranks sum test, and Chi-square tests were used for demographic and presentation differences between the two groups to demonstrate exchangeability between the control (baseline) and treatment (post-protocol change) groups. The primary outcome was initial ionized calcium levels on presentation to the receiving facility, and secondary outcomes of interest were coagulopathy, based on platelet count and INR, total blood product administration, and survival at 24 hours.

Results

131 patients were in the pre-implementation phase and 116 were in the post-protocol change phase. There was no significant difference in age (57.6 vs 55.0 years), sex male (62.6% vs 69.8%), initial vitals, shock index (1.0 vs 1.0) or injury severity score (33.0 vs 30.5). There was a statistically significant improvement in initial ionized calcium levels 4.2(0.6) in the control and 4.5(0.8) in the treatment group, (p=0.026). Initial INR was similar between the two groups (1.4 vs 1.5) (p=0.655), and there was no significant change in platelet count (183.0 vs 198.2 per microliter) (p=0.285). There was no change in survival rates between the control (112, 86.8%) and the treatment groups (99, 86.1%), (p=>0.999). Additionally, there was no change in the amount of blood products administered in the first 24 hours of hospital stay between the two groups, control group received a total of 75 units of blood products and treatment group received 74 units (p=0.389). Of interest there was a significant increase in the amount of pressors given in the post group 27 patients in the control group and 39 patients in the treatment group requiring pressors in the first 24 hours of hospitalization (p 0.033). Not surprisingly there was a significant increase in the amount of TXA (27.6% vs 43.5%) (p=0.016), and calcium given (2.3% vs 19.1%) (p=<.001) in the treatment group, during their prehospital care.

Conclusion

Overall, there was a statistically significant improvement in ionized calcium. However there was no significant difference in coagulopathy, based on INR and platelet count, nor a significant improvement in survival at 24 hours or amount of blood products administered between pre-implementation and post-implementation of empiric calcium co-administration with prehospital blood products. The protocol change did result in an increase in calcium and TXA administration between the pre and post implementation groups.