Update on Cold-Induced Injuries.

Cold-induced injuries are a major challenge for burn surgeons, leading to significant sequelae for the patients including amputations, long-term disability, and death. Rapid assessment and diagnosis are essential for optimal outcomes. Various therapies have emerged to improve outcomes. Topical, oral, and intravenous agents have shown to minimize the impact of cold-induced injuries. Thrombolytics have shown the greatest promise in improving tissue perfusion outcomes in cold-induced injuries. This article provides an update on the evidence-based assessment and management of cold-induced injuries, as well as reviews outcomes and future directions of this challenging pathology.

Prolonged critical avalanche burial for nearly 23 h with severe hypothermia and severe frostbite with good recovery: a case report.

BACKGROUND: Accidental hypothermia with severe frostbite is a rare combination of injuries with a high risk for long-term sequelae. There are widely accepted recommendations for the management of avalanche victims and for frostbite treatment, but no recommendation exists for the treatment of frostbite in severe hypothermic patients, specifically for the management of hypothermic avalanche victims presenting with frostbite. CASE PRESENTATION: We present a case of a previously healthy, 53-year-old male skier who was critically buried by an avalanche at 2300 m of altitude at an ambient temperature of - 8 °C for nearly 23 h. The victim was found with the right hand out of the snow and an air connection to outside. He was somnolent with Glasgow Coma Scale 11 (Eye 4, Verbal 2, Motor 5) and spontaneously breathing, in a severely hypothermic state with an initial core temperature of 23.1 °C and signs of cold injuries in all four extremities. After rescue and active external forced air rewarming in the intensive care unit, the clinical signs of first-degree frostbite on both feet and the left hand vanished, while third- to fourth-degree frostbite injuries became apparent on all fingers of the right hand. After reaching a core body temperature of approximately 36 °C, aggressive frostbite treatment was started with peripheral arterial catheter-directed thrombolysis with alteplase, intravenous iloprost, ibuprofen, dexamethasone and regional sympathicolysis with a right-sided continuous axillary block. After ten months, the patient had no tissue loss but needed neuropathic pain treatment with pregabalin. CONCLUSION: The combination of severe accidental hypothermia and severe frostbite is rare and challenging, as drug metabolism is unpredictable in a hypothermic patient and no recommendations for combined treatment exist. There is general agreement to give hypothermia treatment the priority and to begin frostbite treatment as early as possible after full rewarming of the patient. More evidence is needed to identify the optimal dosage and time point to initiate treatment of frostbite in severely hypothermic patients. This should be taken into consideration by future treatment recommendations.

Oropharyngeal Swelling and Airway Obstruction from Environmental Cold Exposure: A Case Report.

A 19-year-old male presented with facial frostbite and severe oropharyngeal edema after prolonged riding of a snowmobile without any facial covering. The diffuse swelling eventually progressed to airway obstruction, requiring a surgical airway. No alternative explanation was found for his presentation, making this the first case found in the literature of airway obstruction secondary to environmental cold exposure.

Development and validation of clinically Mimicable model of frostbite injury-induced chronic pain.

Frostbite, a debilitating condition, significantly affects the well-being of military veterans and high-altitude residents, causing severe clinical complications such as chronic pain that markedly impacts overall quality of life. There has been a notable increase in the development of pre-clinical models for studying frostbite injury, but their suitability for pain evaluation remains limited. The major hurdle in the development of novel therapeutics for the treatment of frostbite-induced chronic pain is the unavailability of well-established preclinical models. In this study, we employed deep-frozen magnets to induce frostbite injury and conducted validation for chronic pain through assessments of face, predictive, and mechanistic validity. Behavioral assays demonstrated that frostbite injury exhibited significant mechanical, thermal & cold hypersensitivity in rats. Further, molecular analysis indicated that frostbite injury triggered the activation of TRP channels (TRPA1, TRPV1 and TRPM8), microgliosis, and neuroinflammation in the dorsal root ganglion (DRG) and spinal cord of rats. Notably, NR2B protein expressions were significantly upregulated in the DRG of injured rats, while no changes were observed in spinal NR2B expressions. Furthermore, the administration of ibuprofen (25, 50, and 100 mg/kg, i.p.) resulted in a significant improvement in behavioral, biochemical, and molecular alterations in frostbite-injured rats. Overall, results suggested that established frostbite model effectively recapitulates face, pharmacological, and mechanistic validity, highlighting its potential for screening future treatment modalities and exploring the intricate mechanisms associated with frostbite-induced chronic pain.

Acupuncture and herbal medicine in preventing amputation and promoting tissue regeneration in severe frostbite: A case series.

BACKGROUND: Frostbite is a medically significant form of tissue injury that can lead to the potential need for amputation or necessitate tissue regeneration. It occurs most frequently at cryogenic temperatures in extreme altitude climbing, winter sports, and military activities. While acupuncture and herbal medicine have been reported to possess tissue regeneration effectiveness, there is currently no clinical evidence supporting their use in treating grade 3 frostbite cases at risk of amputation. CASE PRESENTATION: Three patients were diagnosed with grade 3 frostbite based on the extent and severity of tissue damage after alpine climbing in the Himalayas. After an urgent treatment, partial body amputation was advised. In order to seek any complementary treatment options and avoid amputation, they were referred to a frostbite expert in traditional Korean medicine. They received a comprehensive treatment consisting of acupuncture, bloodletting, direct moxibustion, and herbal medicine. All the patients showed notable healing of the damaged tissue, which prevented the need for amputation. No adverse effects or other sequelae were observed. CONCLUSION: This case series suggests that complementary medicine, primarily acupuncture and herbal medicine, could be effective for severe frostbite. Further studies with larger sample sizes and control groups are needed to determine the efficacy and safety of this treatment modality for frostbite management.

Cold Weather Injuries Among the Active and Reserve Components of the U.S. Armed Forces, July 2018-June 2023.

Cold injuries are a predictable and preventable threat. Continuous surveillance is essential to prevent cold weather injuries and mitigate their adverse impacts on military operations. Military training and combat operations require continued emphasis on effective cold weather injury prevention strategies and adherence to relevant policies and procedures to protect service members against such injuries. For all active component service members (ACSM), the rate of cold weather injuries in 2022-2023 decreased by 15.2% compared to the preceding cold season. The decrease was most pronounced in the Marine Corps, with a 22.0% reduction in the incidence rate of cold injuries. This year's report includes cold injury rates for the Coast Guard. From July 2022 through June 2023, a total of 423 members of the active (n=376) and reserve (n=47) components of the U.S. Armed Forces had at least 1 cold weather injury. The crude overall incidence rate of cold injury among all ACSM during the 2022-2023 cold season was 28.5 per 100,000 person-years (p-yrs), 15.2% lower than the rate observed during the 2021-2022 cold season (33.6 per 100,000 p-yrs). The rates of cold injuries varied among the Armed Forces, with the highest rates per 100,000 p-yrs observed in the Army, at 50.9, followed by the Marine Corps, at 32.2, the Air Force, at 18.9, the Navy, at 8.1, and the Coast Guard, at 5.1. Consistent with previous cold seasons, frostbite (54.0%) remained the most common type of cold injury among ACSM during the 2022-2023 cold season, while the proportions of hypothermia and immersion injuries were 16.5% and 30.3%, respectively. Cold injury rates among ACSM during the 2018 to 2023 cold seasons were generally highest for males, non-Hispanic Blacks, those under 20 years of age, and enlisted members. The number of cold injuries identified in service members deployed outside the U.S during the 2022-2023 cold season (n=10) was comparable to the 2 preceding cold seasons (11 in 2020-2021 and 12 in 2021-2022), with frostbite accounting for half (n=5) of the 2022-2023 cases.

[Research progress on Huangqi Guizhi Wuwu Decoction and predictive analysis of quality markers].

Huangqi Guizhi Wuwu Decoction is a classic prescription in traditional Chinese medicine(TCM) and is known for its effects of tonifying Qi, warming the meridians, and promoting blood circulation to alleviate obstruction. It is primarily used to treat conditions characterized by Qi stagnation, Yang deficiency, and obstruction, and it exhibits pharmacological effects such as immune regulation, anti-inflammation, analgesia, protection of the cardiovascular and cerebrovascular systems, itch relief, reduction of frostbite symptoms, antioxidative stress, promotion of cell apoptosis, and kidney protection. In modern clinical practice, it is commonly used to treat acute myocardial infarction, sequelae of cerebral infarction, cervical spondylosis, frozen shoulder, lower limb arteriosclerosis, lower limb vascular disorders, peripheral neuropathy in diabetes, and lupus nephritis. Recent research has focused on the chemical components, pharmacological effects, and clinical applications of Huangqi Guizhi Wuwu Decoction. Based on the "five principles" of quality markers(Q-markers) in TCM, this study predicted and analyzed the Q-markers of Huangqi Guizhi Wuwu Decoction. It suggested that astragaloside Ⅳ, formononetin, kaempferol, quercetin, cinnamic acid, cinnamaldehyde, 6-gingerol, paeoniflorin, albiflorin, and gallic acid could serve as Q-markers for Huangqi Guizhi Wuwu Decoction. The findings of this study can provide references for quality control of Huangqi Guizhi Wuwu Decoction and the development of new Chinese medicinal formulations.

Optimum design of the geometry of boots and socks with the aim of minimum weight and preventing frostbite.

In order to design shoes suitable for cold environments, knowledge of the thermal conditions inside the shoes and the variables affecting those conditions is necessary. A two-dimensional model of a boot and sock was developed to investigate the effect of the materials and dimensions of various parts of shoes and to design geometry for them to prevent foot frostbite. The optimization algorithm was used to optimize the dimensions of the boots to maximize the minimum foot temperature with the lowest boot weight. Two types of shoe soles and two kinds of shoe uppers were used to design suitable shoes. The results show the following: (1) In the design boots, the thermal insulation of the toe area plays an essential role in preventing frostbite. Two variables of the thickness of the toe cap and the length of the shoe sole had the greatest impact on the design of shoes with the least weight and the most protection against frostbite. So that to increase minimum foot temperature from 7°C to 15°C, 16°C, or 17°C, only the amounts of these variables should increase. (2) In designing the suitable boot, choosing the proper shoe sole had a significant effect on increasing the thermal insulation in the shoe and reducing its weight. So, for the boot with a minimum foot temperature of 20°C, by changing the shoe sole from EVA08 to EVA12, the weight is reduced by 42%. (3) To maximize the minimum foot temperature, it is necessary to use thick socks.

A multifunctional sensor for real-time monitoring and pro-healing of frostbite wounds.

Flexible epidermal sensors based on conductive hydrogels hold great promise for various applications, such as wearable electronics and personal healthcare monitoring. However, the integration of conductive hydrogel epidermal sensors into multiple applications remains challenging. In this study, a multifunctional PAAm/PEG/hydrolyzed keratin (Hereinafter referred to as HK)/MXene conductive hydrogel (PPHM hydrogel) was designed as a high-performance therapeutic all-in-one epidermal sensor. This sensor not only accelerates wound healing but also provides wearable human-computer interaction. The developed sensor possesses highly sensitive sensing properties (Gauge Factor = 4.82 at high strain), strong mechanical tensile properties (capable of achieving a maximum elongation at break of 600 %), rapid self-healing capability, stable self-adhesive capability, biocompatibility, freeze resistance at -20 °C, and adjustable photo-thermal conversion capability. This therapeutic all-in-one sensor can sensitively monitor human movements, enabling the detection of small electrophysiological signals for diagnosing relevant activities and diseases. Furthermore, using a rat frostbite model, we demonstrated that the composite hydrogel sensor can serve as an effective wound dressing to accelerate the healing process. This study serves as a valuable reference for the development of multifunctional flexible epidermal sensors for personal smart health monitoring. STATEMENT OF SIGNIFICANCE: Accelerated wound healing reduces the risk of wound infection, and conductive hydrogel-based sensors can monitor physiological signals. The multifunctional application of conductive hydrogel sensors combined with wound diagnostic and therapeutic capabilities can meet personalized medical requirements for wound healing and sensor monitoring. The aim of this study is to develop a multifunctional hydrogel patch. The multifunctional hydrogel can be assembled into a flexible wearable high-performance diagnostic and therapeutic integrated sensor that can effectively accelerate the healing of frostbite wounds and satisfy the real-time monitoring of multi-application scenarios. We expect that this study will inform efforts to integrate wound therapy and sensor monitoring.

Management of multiple frostbite casualties at a burn center: San Antonio, Texas, 12-20 February 2021.

BACKGROUND: Frostbite is an insidious disease that normally affects people of cold climates. Winter Storm Uri, which occurred from February 12-20, 2021, created unique metrological conditions for Texas. It caused prolonged sub-freezing temperatures and led to rolling blackouts, affecting 2.8 million Texans including 300,000 people in San Antonio. We report 13 frostbite patients admitted to one burn center during this event. OBJECTIVE: We aimed to determine the at-risk population for frostbite, to categorize their injury severity, and to describe their treatment. A secondary aim was to describe the rehabilitation management of these patients. METHODS: This is a single-center retrospective study. Each patient's injuries were assessed by a topographical grading system. Comparisons were made among those who were admitted to the intensive care unit (ICU), admitted to the progressive care unit (PCU), and treated as outpatients. RESULTS: Thirteen patients were identified. Ten (76.9 %) considered themselves homeless, and 9 (69.2 %) were directly exposed to the elements. The median delay between time of injury and presentation to a medical facility was 3 days (IQR 1-6). Only 3 patients presented to a medical facility within 24 h. Six (46 %) sustained grade 2 injuries, 2 (15 %) sustained grade 3 injuries, and 5 (38%) sustained grade 4 injuries. Only one patient met criteria to receive tissue plasminogen activator (tPA), which was discontinued due to hematochezia. Patients admitted to the ICU, when compared to patients admitted to the ward, had a longer length of stay (median 73 days v. 12 days, p = 0.0215), and required more amputations at below-the-knee or higher levels (3 v. 0, p-value 0.0442). CONCLUSION: In a region unaccustomed and perhaps unprepared to deal with winter storms, the population is particularly vulnerable to frostbite. Lack of awareness of frostbite injuries likely led to the delay in the presentation of patients, which prevented the timely use of tPA. Increasing public awareness may increase readiness.

Frostbite and Mortality in Mountaineering Women: A Scoping Review-UIAA Medical Commission Recommendations.

Kriemler, Susi, Kaste Mateikaite-Pipiriene, Alison Rosier, Linda E. Keyes, Peter Paal, Marija Andjelkovic, Beth A. Beidleman, Mia Derstine, Jacqueline Pichler Hefti, David Hillebrandt, Lenka Horakova, and Dominique Jean; for the UIAA MedCom Writing Group on Women's Health in the Mountains. Frostbite and mortality in mountaineering women: a scoping review-UIAA Medical Commission recommendations. High Alt Med Biol. 24:247-258, 2023. Background: The harsh environment of high altitudes (HA) poses many serious health risks for mountaineers, including cold injuries and death. The aim of this work was to review whether female mountaineers are at special risk for frostbite or death at HA compared with their male counterparts. Methods: The UIAA Medical Commission convened an international author team to review women's health issues at HA and to publish updated recommendations. Pertinent literature from PubMed and Cochrane was identified with additional publications found by hand search. The primary search focus was for articles assessing cold injuries and death in women mountaineers at HA. Results: We reviewed the literature and identified 20 relevant studies: 2 studies on frostbite at HA, plus 7 studies and 1 report for death at HA. An additional 10 studies about frostbite at low altitude were included. We found that female mountaineers at HA were at lower risk of death than their male counterparts, but sex differences in frostbite were inconclusive. Conclusions: The frequency of cold injuries and mortality in female mountaineers is not yet well studied, and the studies that have been published tend to lack precise exposure data. More studies and registries with sex-differentiated data are needed.

Experiences of frostbite injury from recreational use of nitrous oxide canisters in a UK burns center: Not a laughing matter.

Nitrous oxide is used as a recreational drug. Contact frostbite injury from compressed gas canisters has previously been described in the literature, but an increased number of such cases has been noted in our busy regional burns center in the UK. A single-center prospective case series of all patients referred and treated for frostbite injury secondary to misuse of nitrous oxide compressed gas canisters between January and December 2022 is presented. Data collection was performed through a referral database and patient case notes. Sixteen patients, of which 7 were male and 9 were female, satisfied the inclusion criteria. Mean patient age was 22.5 years. The median TBSA was 1%. In total, 50% of patients in the cohort had a delayed initial presentation to A&E of greater than 5 days. Eleven patients were reviewed at our burns center for further assessment and management. In total, 11 patients had bilateral inner thigh frostbite injuries, of which 8 had necrotic full-thickness injury, including subcutaneous fat. Seven patients were reviewed at our burns center and offered excision and split-thickness skin graft. Four patients presented with contact frostbite injury to the hand and one patient to the lower lip. This subgroup was managed successfully with conservative management alone. The reproducible pattern of frostbite injury secondary to the abuse of nitrous oxide compressed gas canisters is demonstrated in our case series. The distinct pattern of injury, patient cohort, and anatomical area affected presents an opportunity for targeted public health intervention in this group.

Prevention and Treatment of Nonfreezing Cold Injuries and Warm Water Immersion Tissue Injuries: Supplement to Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Frostbite.

We convened an expert panel to develop evidence-based guidelines for the evaluation, treatment, and prevention of nonfreezing cold injuries (NFCIs; trench foot and immersion foot) and warm water immersion injuries (warm water immersion foot and tropical immersion foot) in prehospital and hospital settings. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians. Treatment is more difficult with NFCIs than with warm water immersion injuries. In contrast to warm water immersion injuries that usually resolve without sequelae, NFCIs may cause prolonged debilitating symptoms, including neuropathic pain and cold sensitivity.

Can iloprost be used for treatment of cold weather injury at the point of wounding in a forward operating environment? A literature review.

INTRODUCTION: Cold Weather Injury (CWI) represents a spectrum of pathology, the two main divisions being Freezing Cold Injury (FCI) and Non-Freezing Cold Injury (NFCI). Both are disabling conditions associated with microvascular and nerve injury often treated hours after initial insult when presenting to a healthcarestablishment. Given that iloprost is used for the treatment of FCI, could it be used in a forward operating environment to mitigate treatment delay? Is there a role for its use in the forward treatment of NFCI? This review sought to evaluate the strength of evidence for the potential use of iloprost in a forward operating environment. METHODS: Literature searches were undertaken using the following question for both FCI and NFCI: in [patients with FCI/NFCI] does [the use of iloprost] compared to [standard care] reduce the incidence of [long-term complications]. Medline, CINAHL and EMBASE databases were searched using the above question and relevant alternative terminology. Abstracts were reviewed before full articles were requested. RESULTS: The FCI search yielded 17 articles that were found to refer to the use of iloprost and FCI. Of the 17, one referred to pre-hospital treatment of frostbite at K2 base camp; however, this was utilising tPA. No articles referred to pre-hospital use in either FCI or NFCI. DISCUSSION: Although evidence exists to support the use of iloprost in the treatment of FCI, its use to date has been in hospital. A common theme is delayed treatment due to the challenges of evacuating casualties from a remote location. There may be a role for iloprost in the treatment of FCI; however, further study is required to better understand the risk of its use.

Frostbite treated with hyperbaric oxygen.

This is a case report of a 39-year-old man who participated in a cross-country skiing race in Alaska. A few minutes with a glove-free hand resulted in frostbites. Medical assistance arrived 24 hours later and enoxaparine was administered. After seven days, hyperbaric oxygen therapy (HBOT) was initiated in Denmark. After 90 days the distal part of the second finger was removed due to mummification. Compared with the original extent of the injury the amputated part was significantly smaller. HBOT as treatment has not yet been described in Danish patients and is only used on an experimental basis worldwide.

The classification of freezing cold injuries - a NATO research task group position paper.

INTRODUCTION: Freezing cold injuries (FCI) are a common risk in extreme cold weather operations. Although the risks have long been recognised, injury occurrences tend to be sparse and geographically distributed, with relatively few cases to study in a systematic way. The first challenge to improve FCI medical management is to develop a common nomenclature for FCI classification. This is critical for the development of meaningful epidemiological reports on the magnitude and severity of FCI, for the standardisation of patient inclusion criteria for treatment studies, and for the development of clinical diagnosis and treatment algorithms. METHODOLOGY: A scoping review of the literature using PubMed and cross-checked with Google Scholar, using search terms related to freezing cold injury and frostbite, highlighted a paucity of published clinical papers and little agreement on classification schemes. RESULTS: A total of 74 papers were identified, and 28 were included in the review. Published reports and studies can be generally grouped into four different classification schemes that are based on (1) injury morphology; (2) signs and symptoms; (3) pathophysiology; and (4) clinical outcome. The nomenclature in the different classification systems is not coherent and the discrete classification limits are not evidence based. CONCLUSIONS: All the classification systems are necessary and relevant to FCI medical management for sustainment of soldier health and performance in cold weather operations and winter warfare. Future FCI reports should clearly characterise the nature of the FCI into existing classification schemes for surveillance (morphology, symptoms, and appearance), identifying risk-factors, clinical guidelines, and agreed inclusion/exclusion criteria for a future treatment trial.