Continuous Veno-Venous Hemofiltration during Intercontinental Aeromedical Evacuation

Abstract

Overseas contingency operations which occur in areas lacking medical infrastructure pose challenges to the stabilization and transportation of critically ill patients. In particular, metabolic derangements resulting from acute kidney injury (AKI) make long-distance aeromedical evacuation risky. Here, we report the first modern use of in-flight continuous veno-venous hemofiltration (CVVH) for intercontinental aeromedical evacuation. Hospital and transport records were reviewed for a 31-yr-old male active duty service member who sustained 40% total body surface area full thickness burns after high-voltage electrical exposure in the southern Philippines. He was evacuated to the Burns Centre at Singapore General Hospital, where CVVH was initiated for anuric AKI secondary to rhabdomyolysis. The United States Army Institute of Surgical Research (USAISR) Burn Flight Team transported the patient to the USAISR Burn Center at Fort Sam Houston, TX, USA. CVVH was performed in-flight for 15 h out of 19.5 h of total flight time. CVVH settings were maintained as follows: blood flow 250 mL/min; replacement fluid rate 3,500 mL/h; and no ultra-filtrate removal. Unfractionated heparin at 500 units/h was utilized for regional anticoagulation. No filter clotting was encountered; a planned filter change was performed during a midway refueling stop. Pre-flight hyperkalemia was managed with low-potassium replacement fluid. No fluid was removed in the setting of large wound insensible losses. The patient remained hemodynamically stable and required no vasoactive medications. Continuous veno-venous hemofiltration can be used safely during high-altitude flight to evacuate casualties with AKI from distant contingency operations. The use of portable hemodialysis equipment in this case also proves the feasibility of deploying renal replacement therapies to more forward facilities than previously considered.