Abstract

Although blood safety has reached very high standards with respect to infectious complications, delayed or incorrect blood component administration due to human error still represents the greatest transfusion-associated risk. Pretransfusion blood sampling (PTBS) for blood typing and serology testing is a crucial upstream checkpoint in the process chain. In emergencies or disasters, infusion of colloidal plasma expanders and type 0 Rhesus negative red blood cell (RBC) concentrates potentially interfering with blood typing due to red cell pseudoagglutination or mixed-field agglutination, respectively, in theory asks for collection of the very first blood sample along with intravenous (IV) catheter placement at the site of emergency. Vasoconstriction from hemorrhagic shock and unknown patient identity, however, are factors obviating PTBS in this setting. Accordingly, retrospective analysis of 22 patients presenting with WHO grade 4 hemorrhage to a tertiary care emergency center revealed that the PTBS was performed in no instance at the site of trauma. The median time from admission to completion of blood typing was 26 minutes (min; range 13–61). 3 out of 7 severely traumatized and massively transfused patients suffering fatal outcome within 24 hours following admission had no pretransfusion sample taken necessitating transfusion with type 0 RBC concentrates throughout treatment. In one incidence, lack of PTBS contributed to delay in transfusion and death from hemorrhage. In order to facilitate PTBS at the scene of primary care, a new IV catheter system was invented with an integrated blood reservoir containing EDTA anticoagulans. A flexible plastic band holds the reservoir attached to the patient and exerts a forcing function in a way that self-filling of the reservoir following venipuncture has to precede intravenous catheter placement. Upon arrival at the hospital, the reservoir is labeled, disconnected, and immediately sent to the laboratory for blood typing. A prototype version was tested in a randomized controlled phase II clinical trial. Outpatients with traumatic (n=58) or internal hemorrhage (n=7), and patients requiring emergent blood typing for other indications (n=25) were randomized to receive IV access using standard IV catheters or the new system. Handling of the self-sampling catheter was rated comparable to the standard in 90% of treatments by emergency physicians. Blood volumes collected with the emergency IV catheter were sufficient to allow for determination of red cell antigens including Rhesus subgroups, isoagglutinins, and irregular antibodies in 100%, 97%, and 60% of cases, respectively. Repeated blood typing from two truly independent venipunctures under emergency conditions occured in 5/6 patients needing immediate transfusions in the experimental arm as compared to 1/11 patients in the control group. The emergency catheter reduced the mean door-to-blood-type-time from 22.5 min (range: 13 – 121; n=45) to 15 min (range: 7 – 24; n=45; p < .001). ). In conclusion, the novel emergency IV catheter system has the potential to automatically preserve a pretransfusion blood sample unaffected by emergency medication at the scene. It thereby can improve transfusion safety by accelerating pretransfusion serology and by avoiding side effects from immunization and mistransfusion, in particular if targeted to areas where treatment is complex and urgent. It may help to protect the supply with valuable type 0 RBC concentrates in emergency and disaster management.

Disclosures: No relevant conflicts of interest to declare.

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