Variability of Uncrossmatched Blood Use by Helicopter EMS Programs in the United States

Abstract

Study objective: Some helicopter emergency medical services (HEMS) maintain an independent supply of blood for use during transport, although practice is variable and not well described. We aimed to characterize the blood-carrying practices by HEMS programs across the United States.

Methods: Online surveys were sent to the leadership of the 261 HEMS programs nationwide listed in the 2011 Atlas and Database of Air Medical Services (ADAMS) database. We examined blood-carrying practices in aggregate, including typical transport time, proportion of scene transports, and local population density. A GIS (Geographic Information System) and multivariable logistic regression models were used to estimate the impact of characteristics of local practice on each program's decision to carry blood.

Results: A total of 235 (91%) programs responded to the survey, representing 857 of the 929 (92.2%) HEMS rotor wing aircraft nationwide. Fifty-nine (25.3%) programs independently carried blood. A higher proportion of interfacility transports (OR 1.023; 95% CI 1.010-1.036) and decreased local population density (OR 1.006; 95% CI 1.001-1.011) were associated with increased odds of carrying blood. Transport time (OR 1.006; 95% CI 0.991-1.020) and number of transports (OR 1.000; CI 1.000-1.000) were not associated with a program's blood carrying practices. There was no effect of local practices on a program's decision to carry blood (OR 1.002; 95% CI 0.980-1.026).

Conclusion: There is great variability in the utilization of blood by HEMS programs in the United States. Programs that serve more rural areas and programs with a larger percentage of interfacility transports are more likely to independently carry blood.

Keywords: blood transfusion; helicopter EMS; prehospital care; trauma; uncrossmatched blood.