Whole Blood Storage Temperature Investigation in Austere Environments.

INTRODUCTION: Military medical research has affirmed that early administration of blood products and timely treatment save lives. The US Navy's Expeditionary Resuscitative Surgical System (ERSS) is a Role 2 Light Maneuver team that functions close to the point of injury, administering blood products and providing damage-control resuscitation and surgery. However, information is lacking on the logistical constraints regarding provisions for and the stability of blood products in austere environments. METHODS: ERSS conducted a study on the United States Central Command (USCENTCOM) area of responsibility. Expired but properly stored units of stored whole blood (SWB) were subjected to five different storage conditions, including combinations of passive and active refrigeration. The SWB was monitored continuously, including for external ambient temperatures. The time for the SWB to rise above the threshold temperature was recorded. RESULTS: The main outcome of the study was the time for the SWB to rise above the recommended storage temperature. Average ambient temperature during the experiment involving conditions 1 through 4 was 25.6°C (78.08°F). Average ambient temperature during the experiment involving condition 5 was 34.8°C (94.64°F). Blood temperature reached the 6°C (42.8°F) threshold within 90 minutes in conditions 1 and 2, which included control and chemically activated ice packs in the thermal insulated chamber (TIC). Condition 2 included prechilling the TIC in a standard refrigerator to 4°C (39.2°F), which kept the units of SWB below the threshold temperature for 490 minutes (approximately 8 hours). Condition 4 entailed prechilling the TIC in a standard freezer to 0.4°C (32.72°F), thus keeping the units of SWB below threshold for 2,160 minutes (i.e., 36 hours). Condition 5 consisted of prechilling the TIC to 3.9°C (39.02°F) in the combat blood refrigerator, which kept the SWB units below the threshold for 780 minutes (i.e., 13 hours), despite a higher average ambient temperature of almost +10°C (50°F). CONCLUSION: Combining active and passive refrigeration methods will increase the time before SWB rises above the threshold temperature. We demonstrate an adaptable approach of preserving blood product temperature despite refrigeration power failure in austere settings, thereby maintaining mission readiness to increase the survival of potential casualties.

Novel Use of Apple Watch 4 to Obtain 3-Lead Electrocardiogram and Detect Cardiac Ischemia.

BACKGROUND: Early recognition and treatment of ST-elevation myocardial infarction (STEMI) results in better outcomes. OBJECTIVES: To describe a novel technique using the Apple Watch 4 (Apple Inc, Cupertino, CA) to obtain a 3-lead electrocardiogram (ECG) and confirm the watch's feasibility to detect cardiac ischemia in selective cases with a particular injury pattern. METHODS: Two male patients in the Emergency Department had STEMI apparent on their ECGs. These findings were compared with those from the Apple Watch 4, whose positioning was adjusted for 3-lead ECG. RESULTS: The patients' real-time, watch-based, 3-lead ECG tracings matched the traditional ECGs demonstrating STEMI, confirming the potential ability of this device to uncover myocardial ischemia. In each patient, cardiac catheterization revealed severe, 100% occlusion of the right coronary artery. CONCLUSION: The Apple Watch 4 could lead to earlier detection of acute coronary artery disease, but sensitivity and specificity remain unknown.