Kragh JF, O'Conor DK. 23(1). 9 - 16. (Journal Article)
Abstract
We sought to better understand the frostbite risk during first-aid tourniquet use by reviewing information relevant to an association between tourniquet use and frostbite. However, there is little information concerning this subject, which may be of increasing importance because future conflicts against near-peer competitors may involve extreme cold weather environments. Historically, clinical frostbite cases with tourniquet use occurred in low frequency but in high severity when leading to limb amputation. The physiologic response of vasoconstriction to cold exposure leads to limb cooling and causes a reduction of limb blood flow, but cold-induced vasodilation ensues as periodic fluctuations that increase blood flow to hands and feet. In animal experiments, tourniquet use increased the development of frostbite. Evidence from human experiments also supports an association between tourniquet use and frostbite. Clinical guidance for caregiving to casualties at risk for frostbite with tourniquet use had previously been provided but slowly and progressively dropped out of documents. Conclusions: The cause of frostbite was deduced to be a sufficiently negative heat-transfer trend in local tissues, which tourniquet use may worsen because of decreasing tissue perfusion. An association between tourniquet use and frostbite exists but not as cause and effect. Tourniquet use increased the risk of the cold causing frostbite by allowing faster cooling of a limb because of reduced blood flow and lack of cold-induced vasodilation. Care providers above the level of the lay public are warned that first-aid tourniquet use in low-temperature (<0°C [<32°F]) environmental conditions risks frostbite.
Keywords: bleeding control and prevention; first aid; prehospital care; freezing cold injury; complication; wounds and injuries
Bryan CJ, Rush SC, Fuessel-Herrmann D, Bryan AO, Morrow CE, Haskell J, Jones MJ, Bowerfind C, Stephenson JA. 23(1). 18 - 22. (Journal Article)
Abstract
Background: Research among military personnel and veterans indicates that subjective appraisal of warzone stressors explains the relation of combat exposure to posttraumatic stress disorder (PTSD), but not the relation of exposure to injury and death to PTSD. Studies have primarily been limited to conventional forces using aggregate measures of warzone stressor exposure. Threat appraisal may play a different role in the emergence of PTSD among military personnel for whom dangerous deployment experiences are more closely associated with exposure to injury and death, such as US Air Force Pararescuemen and Combat Rescue officers. Materials and Methods: In a sample of 207 rescue personnel, correlations among various types of warzone stressor exposure, threat appraisal, and postdeployment PTSD symptoms were examined. Results: The relative strongest correlates of threat appraisal were stressors related to injury, death, and human remains. Although exposure to these stressors was also correlated with PTSD symptom severity, partial correlations of stressor exposure and PTSD symptoms were no longer significant when adjusting for threat appraisal. Conclusion: Results support the contributing role of threat appraisal to PTSD among military personnel whose primary duties entail exposure to injury and death under hostile and dangerous conditions.
Keywords: PTSD; combat; pararescue; threat appraisal