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ACEM Spring Symposium
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Incidence of hypocalcaemia in adult patients who have received a prehospital blood transfusion from the Auckland HEMS team  

Presentation Description

Blood transfusion can precipitate hypocalcaemia . Hypocalcaemia in both trauma and transfusion has been associated with increased morbidity and mortality (1,2,3). 
Limited current evidence demonstrates that patients receiving prehospital blood transfusion are at high risk of developing hypocalcaemia (4). Consequently, prehospital emergency medical services worldwide administer calcium concurrently with blood transfusion. (3,5,6) 
The NZ Blood Service at ADHB has a partnership with  Northern Rescue Helicopters Limied (NRHL) and provides whole blood for prehospital transfusion of appropriately selected patients.  The current NRHL practice is to administer up to two prehospital units of whole blood. Auckland HEMS use a modified version of the Assessment of Blood Consumption score as a trigger for prehospital transfusion (7,8).  We carry calcium but do not routinely give it alongside transfusions.
To identify the incidence of hypocalcaemia on arrival to the emergency department (ED) post prehospital transfusion.
We reviewed all prehospital blood transfusions given by Auckland HEMS between November 2017 and April 2021.
Patient records were accessed to obtain the Ionised Calcium (iCa) level on arrival to ED. We recorded the 24 hour and 30 day mortality recognising that these variables may not be directly linked. 
Ionised hypocalcaemia was defined as a serum iCa <1.12mmol/L and iCa <0.9mml/L was severe hypocalcaemia(4).
Ethics approval was obtained
65 patients identified. Ten had no iCa available and were excluded. Of the 55 patients, 28 were hypocalcaemic and 5 of these were severe.

Table showing rate of hypocalcaemia (i 

Over half of our cohort are hypocalcaemic on arrival to ED. Auckland HEMS should consider calcium administration concurrently with blood.
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2.         Ditzel, Ricky Michael Jr; Anderson, Justin Lee BHSc; Eisenhart, William Joseph MA; Rankin, Cody Jack; DeFeo, Devin Robert BA; Oak, Sangki BS; Siegler, Jeffrey MD A review of transfusion- and trauma-induced hypocalcemia: Is it time to change the lethal triad to the lethal diamond?, Journal of Trauma and Acute Care Surgery: March 2020 - Volume 88 - Issue 3 - p 434-439 doi: 10.1097/TA.0000000000002570  
3.          Byerly, S., Inaba, K., Biswas, S. et al. Transfusion-Related Hypocalcemia After Trauma. World J Surg 44, 3743–3750 (2020). 
4.         Kyle T, Greaves I, Beynon A, Whittaker V, Brewer M, Smith J. Ionised calcium levels in major trauma patients who received blood en route to a military medical treatment facility. Emerg Med J. 2018 Mar;35(3):176-179. doi: 10.1136/emermed-2017-206717. Epub 2017 Nov 24. PMID: 29175878. 
5.        Cap A, Gurney J, Spinella P, et. al.Damage Control Resuscitation (CPG ID:18). Joint Trauma Service Clinical Practice Guideline. Joint Trauma System, the Department of Defense Center of Excellence for Trauma. 2019
6.        NSW Ambulance  AO.CLI.19 - CLINICAL PRACTICE STANDARD –– Aeromedical Operations - Traumatic Haemorrhage Control. July 2020
7.        Nunez TC, Voskresensky IV, Dossett LA, Shinall R, Dutton WD, Cotton BA. Early prediction of massive transfusion in trauma: simple as ABC (assessment of blood consumption)? J Trauma. 2009 Feb;66(2):346-52. doi: 10.1097/TA.0b013e3181961c35. PMID: 19204506. 
8.        Auckland HEMS whole blood transfusion Standard Operating Procedure