Field-expedient thawing of fresh-frozen plasma

INTRODUCTION: Frozen plasma is superior to crystalloids for hemorrhage resuscitation but remains logistically challenging in austere environments because of specialized clinical equipment for on-demand thawing. This research examines some ad hoc thawing techniques that have been implemented by military medical personnel. METHODS: Fresh-frozen plasma (FFP) units were thawed accordingly: using a slow cooker (three temperature settings) with preheated or room temperature water; affixing flameless ration heaters from meals ready-to-eat (MREs) to FFP and submerging in water; exposing FFP to electric kettle-boiled water; incubating with a sous vide immersion circulator; or using a clinical thawer (control). Hemostatic function, thrombin generation, factor activities, and essential chemistry were measured after thawing. RESULTS: Even at the highest temperatures, without preheated water the slow cooker doubled thawing time (62.5 min vs. control, 32.5 min; p < 0.0001), and the final temperature was 13.5°C versus 28.8°C in control (p < 0.01). When preheated, the slow cooker thawed in 31.3 minutes (p < 0.05), with a final temperature of 22.4°C. Kettle-boiled water thawed in 23.0 minutes with a final temperature of 25.1°C. The sous vide thawed in 28.1 minutes, with a final temperature of 20.2°C. MRE heaters were insufficient. Functional measures were similar in all conditions. DISCUSSION: In emergencies, protracted plasma thawing is unacceptable, and slower thawing methods also produced cryoprecipitate. Although no functional changes were observed with boiled water thawing, potential negative physiological impacts must be examined. Safe, controlled thawing can be obtained with the sous vide, although optimization requires further testing.