Cold-Induced Vasodilation, Rewarming, and Dexterity Impairment Following Second-Degree Frostbite.

Frostbite, a severe cold injury resulting from exposure to subfreezing temperatures, damages the skin and underlying tissues of the affected area and ranges in severity from first to fourth degree. This case report investigates the impact of second-degree frostbite suffered by a marine during winter training on cold-induced vasodilation (CIVD). Comparisons of CIVD before and after the injury revealed significant alterations in CIVD responses. CIVD, a physiological mechanism characterized by blood vessel dilation in response to cold exposure, plays a crucial role in operating in cold-weather environments and enhancing dexterity. The marine exhibited prolonged CIVD onset time, lower finger temperatures, increased pain sensations, and diminished dexterity after the frostbite injury during follow-up CIVD testing. The findings suggest that the frostbite-induced damage possibly compromised the microvascular function, contributing to the observed changes in CIVD. The marine reported persistent cold sensitivity and difficulty in maintaining hand warmth when assessed postinjury. This case underscores the potential long-term consequences of frostbite on CIVD and manual dexterity, emphasizing the importance of understanding these physiological changes for individuals engaged in cold-weather activities, particularly for military and occupational personnel.

Deep frostbite: Clinical characteristics and outcomes in northeastern China.

OBJECTIVE: To investigate the clinical characteristics and treatment outcomes in patients with severe frostbite in a single institution in northeastern China. METHODS: The clinical records of patients with severe frostbite of the extremities who were hospitalized at the authors' institution between January 2009 and April 2019 were retrospectively reviewed. Demographic data, predisposing factors, clinical presentation, duration of signs and symptoms, number of surgical interventions, and length of hospital stay were extracted and analyzed. RESULTS: A total of 156 consecutive inpatients were treated for severe frostbite with the mean age was 43.7 ± 14.15 years. Hands were the most common site involved (38.5%). The most prevalent predisposing factor for frostbite included alcohol abuse (41.67%), smoking habits (37.18%) and psychiatric illness (14.11%). Mean duration of signs and symptoms was 3.6 days. Most of patients (37.8%) sustained frostbite injury in January. All patients survived, and the mean length of hospital stay was 45.6 days (range, 29-62). Amputations of limbs were performed in 40.4% of patients. CONCLUSION: The incidence of deep frostbite in Jilin province correlates with the environmental temperature and is often associated with alcohol abuse, smoking and other psychosocial factors. Delayed presentation would increase the risk of amputation. These findings should guide clinical decisions about the treatment of individual patients with deep frostbite.

Ski-Everest (8848 m) Expedition: Digit Skin Temperature Responses to Cold Immersion May Reflect Susceptibility to Cold Injury.

INTRODUCTION: We tested the hypothesis that individual susceptibility to freezing cold injury might be reflected in an attenuated cold-induced vasodilatation (CIVD) response by comparing the CIVD responses of an elite alpinist with a history of freezing cold injury in the feet (case alpinist) with those of an age- and ability- matched noninjured alpinists control group (controls). According to this hypothesis, the vasomotor responses to a CIVD test of the case alpinist would represent a pathophysiological response when compared with the normal physiological response of a noninjured cohort. METHODS: The case alpinist and the controls in the cohort group conducted a cold water immersion test comprising sequential immersion of a hand and foot for 5 min in 35°C water, followed by a 30-min immersion in 8°C water and a 10-min recovery period in room air. During this test we monitored the finger and toe skin temperatures. RESULTS: The case alpinist had a significantly attenuated CIVD response and a lower skin temperature in all injured and noninjured digits during immersion (∼2°C lower than in the control group) and an attenuated recovery of finger skin temperatures (∼6°C lower than in the control group). CONCLUSIONS: The attenuated CIVD response of the case alpinist may reflect a previously unrecognized enhanced susceptibility to frostbite. In addition to the poor vasomotor response observed in the injured toes, he also exhibited a poor vasomotor response in his noninjured fingers. The results of the present study indicate that a test of vasomotor activity during thermal stress may identify individuals predisposed to cold injury.

Frostbite-A Case Series From Arctic Greenland.

Greenland is not only the largest island in the world, it is also the least densely populated country on the globe. The majority of Greenland's landmass lies within the Arctic Circle. Weather conditions in Arctic areas can be extreme, thus exposing locals and visitors to a high risk of acquiring frostbite injuries. More than two thirds of Greenland is covered by a permanent ice sheet, and temperatures can drop to below -70°C. In addition, frequent storms, occupational exposure, and alcohol all contribute to an increased risk for frostbite injury. Frostbite may cause major morbidity, including tissue loss and limb amputation. Hence, proper diagnosis and treatment of frostbite injuries is of utmost importance. We present 6 cases of frostbite injuries in Greenland, ranging from mild to severe frostbite in both locals and foreign visitors. The cases illustrate some of the known risk factors for frostbite injuries. The etiology, pathophysiology, clinical presentation, and recommended management of frostbite are summarized. Novel treatments for frostbite and frostbite sequelae are discussed in the context of the Greenlandic healthcare system. Furthermore, cultural aspects and reasons for a seemingly low incidence of frostbite injuries in Greenland are explored.

[The forensic medical assessment of the causes and conditions of the formation of the chilling injury]. / Sudebno-meditsinskaia otsenka prichin i uslovii vozniknoveniia kholodovoi travmy.

The authors present the data of the literature publications and theoretical considerations concerning the causes and conditions behind the formation of the chilling injury. It is demonstrated that the chilling injury develops as a consequence of a disturbance in the relationship between the hypothermic protection of the organism and the cooling potential of its environment. The thermal balance of the human organism depends not only on the natural mechanisms of physical and chemical thermoregulation but also on the character of artificial thermoregulation including the man-made means of cold protection. The critical evaluation of all the available data on chilling injuries to the human body gave evidence that the causes and conditions of their development can be highly multivarious which does not however exclude the possibility of their systematization.

Catheter-Directed Intraarterial Thrombolysis as Part of a Multidisciplinary Management Protocol of Frostbite Injury.

PURPOSE: To evaluate intraarterial catheter-directed thrombolysis for prediction and prevention of delayed surgical amputation as part of multidisciplinary management of frostbite injury. MATERIALS AND METHODS: A retrospective review was performed of 13 patients (11 men, 2 women; median age, 33.4 y; range, 8-62 y) at risk of tissue loss secondary to frostbite injury and treated with catheter-directed tissue plasminogen activator (t-PA) thrombolysis. Amputation data were assessed on follow-up (mean, 23 mo; range, 9-83 mo). Angiographic findings were classified into complete, partial, and no angiographic response and assessed for association with follow-up amputation rates. Correlation between amputation outcome and duration of cold exposure (mean, 23 h; range, 5-96 h), time between exposure and rewarming therapy (mean, 25.5 h; range, 7-95 h), and time between exposure and t-PA thrombolysis (mean, 32 h; range, 12-96 h) was assessed. Complications were recorded. RESULTS: Of 127 digits at risk on baseline angiography that were treated with catheter-directed thrombolysis, complete recovery was seen in 106 (83.4%). Total mean t-PA dose per extremity was 27.5 mg (range, 12-48 mg) over a mean period of 34 hours (range, 12-72 h). Patients with complete angiographic response (8 patients; 79.5% of digits) did not require amputations; 4 of 5 patients (80%) with partial angiographic response (20.5% of digits) underwent amputation (P = .007). There was no significant correlation between amputation rates and duration of cold exposure (P = .9), time to rewarming therapy (P = .88), and time to thrombolysis (P = .56). Femoral access site bleeding in 2 patients was managed conservatively. One patient underwent surgical exploration for brachial artery hematoma. CONCLUSIONS: Intraarterial catheter-directed thrombolysis should be included in initial management of frostbite injury, as it may prevent delayed amputations. The degree of angiographic response to thrombolysis can potentially predict amputation outcomes.

Pathophysiologic Determination of Frostbite Under High Altitude Environment Simulation in Sprague-Dawley Rats.

OBJECTIVES: Pathophysiologic changes of frostbite have been postulated but rarely understood, especially the changes caused by chilly high altitude environment. Therefore, we investigated the pathophysiologic changes of high altitude frostbite (HAF) caused by cold and hypoxia. METHODS: Forty Sprague-Dawley rats were randomly divided into 5 equal groups, namely, control, superficial HAF (S-HAF), partial-thickness HAF (PT-HAF), full-thickness HAF (FT-HAF), and partial-thickness normal frostbite (PT-NF) groups. The S-HAF, PT-HAF, and FT-HAF groups were fed under hypobaric hypoxic conditions simulating an altitude of 5000 m. Then, the PT-NF, S-HAF, PT-HAF, and FT-HAF models were constructed by controlling the duration of the direct freezing by liquid nitrogen. Animal vital signs were measured after the operation, and histopathologic changes were observed after routine hematoxylin and eosin staining. In addition, the microcirculation of frostbite tissues was monitored and compared by contrast ultrasonography during wound healing. RESULTS: The S-HAF, PT-HAF, and FT-HAF groups showed significant differences in the microcirculatory and histopathologic changes in the various tissue layers (P < .05). In addition, combined cold and hypoxia caused more damage to frostbite tissue than pure cold. The circulation recovery of HAF models was significantly slower relative to NF models (P < .05). CONCLUSIONS: A safe and reproducible HAF model was proposed. More important, pathophysiologic determination of HAF provided the foundation and potential for developing novel and effective frostbite therapies.

Frostbite of both first digits of the foot treated with delayed hyperbaric oxygen:a case report and review of literature.

BACKGROUND: Frostbite is an uncommon event that can occur from exposure to temperatures below -4 degrees C and can lead to potential serious tissue damage and necrosis. This in turn can result in debilitating amputations in otherwise healthy people. The pathophysiological mechanisms of frostbite have marked similarities to those seen in thermal burns, ischemia/reperfusion injuries and crush injuries--i.e., non-healing wounds and inflammatory processes. These injuries are commonly treated with hyperbaric oxygen therapy. OBJECTIVES: Evidence for treating frostbite with hyperbaric oxygen (HBO2) is scarce, and to date HBO2 is not a standard addition in the multidisciplinary care of freezing injuries. We aim to contribute to the available evidence with a case report and review the literature to reassess the multidisciplinary treatment of frostbite injuries. CASE REPORT AND REVIEW OF LITERATURE: We present a case report of a woman with deep frostbite of the toes treated with hyperbaric oxygen therapy, after a delay of 21 days, with good results. No surgical intervention was needed. A literature search revealed 17 human case reports on frostbite and four animal studies in which hyperbaric oxygen was applied. All case reports showed positive effects, and in none of the cases was amputation necessary. In the animal studies, two showed significant positive results regarding tissue loss and reduction of inflammatory markers, whereas two did not. CONCLUSIONS: Based on our case report as well as the literature and the mechanisms of hyperbaric oxygen, we make the recommendation that this therapy be considered as an addition to the multidisciplinary treatment of frostbite, even after significant delay of treatment.

Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite: 2014 update.

The Wilderness Medical Society convened an expert panel to develop a set of evidence-based guidelines for the prevention and treatment of frostbite. We present a review of pertinent pathophysiology. We then discuss primary and secondary prevention measures and therapeutic management. Recommendations are made regarding each treatment and its role in management. These recommendations are graded on the basis of the quality of supporting evidence and balance between the benefits and risks or burdens for each modality according to methodology stipulated by the American College of Chest Physicians. This is an updated version of the original guidelines published in Wilderness & Environmental Medicine 2011;22(2):156-166.

[Resuscitation of vital activity after cold arrest of respiration by physiological methods without rewarming the body].

BACKGROUND: The arrest of respiration during deep hypothermia means death, though at a low temperature the heart may rhythmically contract for 30-40 minutes more. The attempts of rewarming only shorten the time before the heart arrest. Calcium ions (Ca2+) are believed to accumulate in the nervous cells in cold. An excess of these ions inhibits the metabolism. Moreover it stimulates the cell proteases, which destroy the cell membranes. AIM: The aim of the study was to make the the attempts to develop the methods of stimulating the respiration and heart without rewarming the body. MATERIALS AND METHODS: The work was carried out on wite rats 250-320g in weight. We introduced disodium salt of ethylenediaminetetraacetic acid into the animals. The second method of blocking the mechanisms of the cold death was artificial respiration. RESULTS: Ethylenediaminetetraacetic acid reacts with calcium ions, decreases their quantity in the blood, and, consequently, in a complex manner in the cell protoplasm. Artificial respiration not only increases the flow of oxygen into an organism but also decreases the lowest temperature threshold of the cold death of an organism. CONCLUSION: A decrease in the surviving threshold by 1.5-1.8 degrees C is very important from the point of view of reanimation of an organism since to preserve life in the critical period of reanimation each 0.5 degrees C are important. Prolongation of minimal frequency of heart contractions and maintaining a minimal arterial blood pressure in an overcooled organism given the body temperature of 11-12.5 degrees C is a special problem of great interest associated with many physiological and biological parameters.

Recognition and treatment of freezing and nonfreezing cold injuries.

This article reviews recent medical literature to provide an overview of the recognition and treatment of the two broad categories of cold injuries, freezing and nonfreezing. Frostbite, a freezing cold injury, is treated traditionally with rapid rewarming followed by tissue care and surgical debridement of necrotic tissue. Recently, newer therapies aimed at prevention of tissue necrosis have shown improved outcomes compared with more traditional therapies. These newer treatment regimens for frostbite include the use of various drugs such as ibuprofen, aspirin, warfarin, tissue plasminogen activator, and prostacyclin. The use of Tc bone scans, magnetic resonance imaging arthrogram, or angiography may have prognostic value for early determination of the extent of tissue loss. The more common nonfreezing cold injuries, though less severe than frostbite, may lead to short- and long-term complications requiring treatment and are discussed also.

[Hypothermia, chilblain and frostbite].

Many factors such as the environmental conditions (temperature and humidity etc.), a nutritional status, the degree of fatigue, a moisturizing state of the body, clothes, the sensitivity to coldness are involved in an outbreak of hypothermia. Children, aged persons and the presence of an underlying disease are also risk factors related to the occurrence of hypothermia. The dysfunction of the respiratory system, the circulatory system and the central nervous system is caused by a decrease in body temperature. Finally, death is brought about at 25 degrees C of body temperature or lower. Frostbite develops when tissue is exposed to -4 degrees C of coldness or lower. The extent of injury is determined by the magnitude of coldness.

The effect of stromal vascular fraction in an experimental frostbite injury model.

BACKGROUND: Despite current treatment modalities, frostbite remains an injury with a poor prognosis which may cause functional morbidities. Several experimental and clinical studies have demonstrated that stromal vascular fraction is an autologous mixture, which can improve wound healing and vasculogenesis. The aim of this study was to show the beneficial effects of stromal vascular fraction on experimental frostbite healing. MATERIAL AND METHODS: Stromal vascular fraction (SVF) was harvested from 5 rats after excision of the inguinal fat pads. Another 20 rats were separated into 2 groups of 10 as the SVF group and the control group. A frostbite injury was created on each rat using a cryoprobe frozen with liquid nitrogen (-196 °C). SVF was applied to the SVF group and phosphate-buffered saline to the control group. All injections were performed subcutaneously within the frostbite injury area. Biopsies were performed on days 5 and 14 for histopathological and immunochemical evaluations. The tissue perfusion rates of both groups were assessed on day 14 using indocyanine green angiography (SPY system). RESULTS: The increase in mean tissue perfusion was 373.3% ( ± 32.1) in the SVF group and 123.8% ( ± 16.3) in the control group (p < 0.001). The macroscopic wound reduction rates of the SVF and control groups were 25.5% ( ± 19.1) and 18.0% ( ± 5.9), respectively on day 5%, and 78.2% ( ± 9.2) and 57.3% ( ± 16.7) on day 14 (p = 0.007; p = 0.003). Acute inflammation and the fibrosis gradient were significantly decreased in the SVF group compared to the control group (p = 0.004, p = 0.054 respectively on day 14). Granulation tissue amount, re-epithelialization score and neovascularization were significantly increased in the SVF group (p = 0.006, p = 0.010 and p = 0.021, respectively on day 14). CONCLUSIONS: The study results demonstrated that SVF increases frostbite wound healing by increasing tissue perfusion rate, neovascularization and re-epithelialization, and modulating acute inflammation and fibrosis.

Dynamic adaptation of the peripheral circulation to cold exposure.

Humans residing or working in cold environments exhibit a stronger cold-induced vasodilation (CIVD) reaction in the peripheral microvasculature than those living in warm regions of the world, leading to a general assumption that thermal responses to local cold exposure can be systematically improved by natural acclimatization or specific acclimation. However, it remains unclear whether this improved tolerance is actually due to systematic acclimatization, or alternately due to the genetic pre-disposition or self-selection for such occupations. Longitudinal studies of repeated extremity exposure to cold demonstrate only ambiguous adaptive responses. In field studies, general cold acclimation may lead to increased sympathetic activity that results in reduced finger blood flow. Laboratory studies offer more control over confounding parameters, but in most studies, no consistent changes in peripheral blood flow occur even after repeated exposure for several weeks. Most studies are performed on a limited amount of subjects only, and the variability of the CIVD response demands more subjects to obtain significant results. This review systematically surveys the trainability of CIVD, concluding that repeated local cold exposure does not alter circulatory dynamics in the peripheries, and that humans remain at risk of cold injuries even after extended stays in cold environments.

Determination of microcirculatory changes and angiogenesis in a model of frostbite injury in vivo.

BACKGROUND: The breakdown of skin microcirculation and the leukocyte-endothelium interaction are assumed to play a key role in the pathophysiology of frostbite injuries. However, little is known as yet. The aim was to develop an in vivo frostbite model to monitor microcirculatory changes and angiogenesis after frostbite injury. MATERIALS AND METHODS: Deep partial thickness frostbite injuries were inflicted with a no-touch-technique to the ears of hairless mice (n=9). To this end, a gas jet of nitrogen vapor (T=-195,8±2.7°C) was delivered onto an area of 1.9 mm(2) for 1,5 s. Intravital fluorescent microscopy in combination with FITC-dextran and Rhodamin 6G as fluorescent dyes was used to assess microcirculatory changes, leukocyte behavior, and angiogenesis during the 14 d of wound healing. RESULTS: The area of no perfusion decreased significantly over the observed period, and perfusion was almost completely restored due to angiogenesis by d 14 (day 1: 1.89 [mm(2)]±0.44SEM, d 14: 0.02±0.01). No post-traumatic extension of the trauma could be observed. Edema formation increased significantly up to d 7. The number of adherent leukocytes showed a significant increase during the first 7 d. Functional vessel density showed a significant post-frostbite decrease to 60% of the baseline value. CONCLUSIONS: This novel frostbite model provides a simple and nonetheless highly effective technique of creating locally limited reproducible frostbite injuries using a no touch technique. Tissue damage can be fully attributed to the thermal trauma, and the model allows repetitive intravital fluorescent microscopy of the microcirculation, leukocyte-endothelium interaction, and angiogenesis.

Intravital pathophysiologic comparison of frostbite and burn injury in a murine model.

BACKGROUND: The breakdown of skin microcirculation and the leukocyte-endothelium interaction are assumed to play key roles in the pathophysiology of burn and frostbite injuries. Available data on frostbite and burn injuries were collected using different experimental models and setups, which limits direct comparisons of these thermal traumata significantly. To determine pathophysiologic similarities and differences, two comparable in vivo frostbite and burn models were used to assess microcirculatory and angiogenetic changes in burn and frostbite injuries. MATERIALS AND METHODS: Either deep partial thickness no-touch burns or frostbite injuries were inflicted to the ears of hairless mice (n = 40) by a hot or cold gas jet (117.0 ± 2.1°C for 1 s and -195.8 ± 2.7°C for 1.5 s, respectively) resulting in a necrotic, nonperfused area of about 1.56 ± 0.28 mm2. Intravital fluorescent microscopy was used in combination with fluorescent dyes in order to assess the microcirculation, angiogenesis, and leukocyte-activity over a 12-d period. RESULTS: The angiogenesis occurred significantly faster after frostbite than after burn (16.4% ± 4.5% versus 30.6% ± 2.8% nonperfused area, compared with the baseline value on d 7 (P = 0.009)). The loss of functional vessel density was significantly more pronounced after frostbite (57.6% ± 2.2% versus 89.2% ± 4.9% (P < 0.001)). However, the area recovered faster. The edema formation, as a parameter for endothelial integrity, was significantly more pronounced and lasted longer after frostbite, compared with the burn injury, and reached its maximum level on d 7 after trauma (162.4% ± 4.2% versus 142.% ± 5.9%; P = 0.007). In contrast to the rolling leukocytes, which showed the same increase on d 1 and then a subsequent decrease in both groups, the number of adherent leukocytes after the burn was markedly higher on d 1 (480% versus 167%; P = 0.001) but decreased much faster. The number of adherent leukocytes after frostbite remained significantly higher than those of the burn group during the entire observation. CONCLUSION: The comparison of analogous intravital burn and frostbite models indicates that despite the similarities, decisive microcirculatory differences in extension and recovery from these two types of thermal trauma exist.

Wilderness Medical Society practice guidelines for the prevention and treatment of frostbite.

The Wilderness Medical Society convened an expert panel to develop a set of evidence-based guidelines for the prevention and treatment of frostbite. We present a review of pertinent pathophysiology. We then discuss primary and secondary prevention measures and therapeutic management. Recommendations are made regarding each treatment and its role in management. These recommendations are graded based on the quality of supporting evidence and balance between the benefits and risks/burdens for each modality according to methodology stipulated by the American College of Chest Physicians.

A clinical review of the management of frostbite.

Frostbite is a thermal injury that can occur when temperatures drop low enough for tissue to freeze. On rewarming the tissues, an inflammatory process develops which is often associated with tissue loss. The extent of the tissue loss reflects the severity of the cold exposure and includes factors such as temperature, duration, wind chill, altitude, and systemic hypothermia. This review discusses the epidemiology, the pathophysiological processes involved, and the clinical management of frostbite injuries. Practical advice is given on both the field and hospital management and how to seek expert advice from remote situations. The review also discusses newer developments in frostbite treatment such as intra-vascular thrombolysis and adjunctive treatments such as the use of intravenous vasodilators.

[Frostbite due to recreational nitrous oxide use]. / Bevriezingswonden door recreatief lachgasgebruik.

BACKGROUND: There is a new type of injury that is observed increasingly often: frostbite of the thighs that has occurred as result of holding a cylinder containing nitrous oxide in position between the legs during recreational use of said substance. Because skin symptoms are often mild in the first few days after the event, the severity of the injury is often not recognized. However, patients can suffer serious scarring from this type of injury. CASE DESCRIPTION: We present two cases involving young patients who were referred to the burns unit with lesions sustained through nitrous oxide use. Upon inspection we observed deep frostbite wounds, which necessitated operative treatment. The patients had to undergo multiple operations and remained under our care for management of their scars. CONCLUSION: It is important to recognize this injury and to consult one of the burns units to treat these patients in a timeline and appropriate manner.