The Effect of Blood Transfusion during Air Medical Transport on Transport Times in Patients with Ruptured Abdominal Aortic Aneurysm

Abstract

Background: Patients presenting with a diagnosis of ruptured abdominal aortic aneurysm (RAAA) to community hospitals must be transported to tertiary care centers, where necessary resources are available. Unfortunately, guidelines for treatment of RAAA lack high-level evidence on the optimal resuscitation of RAAA patients during transport. We hypothesized that transfusion of packed red blood cells (PRBCs) during transport would not delay transport times in patients with RAAA. Methods: We performed a retrospective analysis of a prospective registry including prehospital data of patients with RAAA presenting to a single academic hospital in Western Pennsylvania between 2001 and 2019. Our primary outcomes were prehospital transport times: "transport interval" and "total interval." "Transport interval" is the duration from patient pickup at the outside hospital (OSH) to arrival at the receiving facility. "Total interval" is the duration from dispatch of the air medical transport to arrival of the patient to the receiving facility. We then compared two groups of patients, stratified by the receipt of PRBCs in transit, by reporting mean difference (95% confidence interval: CI) for continuous variables and percent difference (95% CI) for categorical variables. We performed two multivariate linear regression models to test if there was any effect of the receipt of PRBCs in transit on transport times. Results: We included 271 patients with RAAA transported by our air ambulance system who underwent an operation at the receiving facility, 99 (37%) of whom received PRBCs in transit. Mean ± standard deviation (SD) of the total intervals were 67 ± 28 and 71 ± 42 minutes, among patients who received or did not receive PRBCs in transit respectively, with no significant difference (p = 0.437). Following adjusted analysis, the receipt of PRBCs during transport was not associated with increased transport times, after accounting for age, hypotension, endovascular aneurysm repair (EVAR), and PRBC transfusion at the OSH. Conclusion: PRBC transfusion during air medical transport in patients with RAAA did not delay transport times.

Keywords: air medical transport; blood transfusion; packed red blood cells; ruptured abdominal aortic aneurysm; transport time.

Figure 1.a.

Box plot of the median transit time (minutes) spent in transit from the OSH to the final destination (transport interval), stratified by the receipt of PRBCs in transit. Figure 1.b. Box plot of the median overall transit time (minutes) since dispatch to the final destination (total interval), stratified by the receipt of PRBCs in transit.