Helicopter “Drip and Ship” Flights Do Not Alter the Pharmacological Integrity of rtPA

Abstract

IntroductionRural and critical access hospitals rely on the “drip and ship” practice using helicopter emergency medical services (HEMS). But those helicopter flights are an unusual environment with physical factors such as vibration and accelerations that could potentially affect the stability, and pharmacological properties of IV rtPA, an issue that has not been previously addressed. Materials and MethodsThis was a prospective cohort study of consecutive acute ischemic stroke patients receiving IV rtPA through a Comprehensive Stroke Center from November 2015 to February 2017 to measure the effects of HEMS on the integrity and activity of rtPA by collecting residual medication left in the vial. Clinical Trial Registrationhttp://www.clinicaltrials.gov. NCT02752256 ResultsA total of 33 patients and rtPA samples were included; 18 patients who presented directly to the Comprehensive Stroke Center emergency department and 15 patients who received rtPA during air ambulance transfer. The median rtPA antigen concentration in the residual medication vial was 3.04 mg/mL (IQR: 1.24-3.87) in the HEMS group and 1.91 mg/mL (IQR: 1.33-2.60) in the controls (P = .168). There were no significant differences in rtPA activity or specific activity between the HEMS and control groups and there was no association between total HEMS flight time on overall rtPA specific activity. ConclusionsIn summary, this study provides supportive evidence of the lack of a detrimental effect of the HEMS physical environment on the integrity of rtPA, therefore endorsing current drip and ship practices without infusion adjustments.