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.

[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.

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.

Treatment of Frostbite With Hyperbaric Oxygen Therapy: A Single Center's Experience of 22 Cases.

INTRODUCTION: Frostbite is well documented in the military and countries with extreme temperatures, and it is most likely due to increased exposure to cold temperatures and/or risk-taking behavior. Severity of injury depends on absolute temperature, wind chill, duration of exposure, wet or dry cold, immersion, clothing quality, and substance use. Hyperbaric oxygen therapy (HBOT) has been described as a treatment option but only in small case series. OBJECTIVE: The aim of this retrospective study is to describe the usage patterns, side effects, and outcomes of HBOT used as an adjunct to wound care at a single major Canadian university hospital. MATERIALS AND METHODS: A retrospective review of patients with frostbite injury admitted and treated with HBOT between January 2000 and March 2015 was performed. A total of 22 patients were studied. Available data included patient demographics, duration of exposure to cold temperature, severity of injury, time to HBOT, duration of therapy, side effects of therapy, concurrent therapies (dressing, anticoagulation, antibiotics), bone scan results, and consequent level of amputation. RESULTS: The cohort consisted mostly of men (18, 81.8%) and patient mean age of 40 years (range, 13-70 years). Ten patients (45.5%) were intoxicated at the time of injury, and psychiatric illness was implicated in 9 (40.9%) patients. Of the presented injuries, 17 (77.3%) had frostbite to the upper extremity. Bone scans were performed on 16 (72.7%) patients. In 4 patients, the absence of radiotracer activity correlated with a protective effect on subsequent amputation levels. All patients received anticoagulant therapy. Of the 22 patients, 16 (72.7%) experienced at least 1 side effect of HBOT, including otologic barotrauma, nausea, vomiting, anxiety, oxygen toxicity seizure, and myopic changes. All study patients recovered without permanent sequelae; it is unclear whether HBOT reduced soft-tissue damage or amputation rates. CONCLUSIONS: This is the largest cohort reported in the literature of patients with frostbite injuries treated with HBOT. Hyperbaric oxygen therapy may show positive impact on the demarcation level of frostbite and, despite the common side effects, it generally causes no long-term sequelae.

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.

The Effect of a 300 mBar Increase in Barometric Pressure on Digital Microcirculation in Healthy Subjects Exposed to High Altitude: Is the Use of a Portable Hyperbaric Chamber to Treat Frostbite and/or Hypothermia in the Field Indicated? (Flow_Pulse Study).

INTRODUCTION: Hypothermia and frostbite occur when there is a significant decrease in central and peripheral body temperature in individuals exposed to cold windy conditions, often at high altitude or in a mountain environment. Portable hyperbaric chambers increase the barometric pressure and thereby the partial pressure of oxygen inside the chamber, and their use is a well-known treatment for altitude illness. This study aims to show that a portable hyperbaric chamber could also be used to treat hypothermia and frostbite in the field, when rescue or descent is impossible or delayed. METHODS: During a European research program (SOS-MAM, Flow Pulse study) measurements were taken from 27 healthy nonacclimatized voluntary subjects (21 men, 6 women, mean age 41 ± 17) at an altitude of 3800 m (Chamonix Mountain Lab, Aiguille du Midi, France) right before and immediately after spending 1 hour in a portable hyperbaric chamber at 300 mbar. We measured digital cutaneous temperature (Tcut), digital cutaneous blood flow (Fcut), digital tissue oxygenation (TcPO2), blood oxygen saturation (SpO2), heart rate, and core temperature. Air temperature inside the chamber (Tchamb) was measured throughout the whole session. RESULTS: We observed significant increases in Tchamb: 9.3°C compared with the outside temperature, Tcut: +7.5°C (±6.2°C 71%), Fcut: +58PU (±89) (+379%), TcPO2: +18 mmHg (±11.9) (304%), and SpO2: 13%. CONCLUSION: This study shows that a portable hyperbaric chamber can be used to treat frostbite and/or hypothermia in the field at altitude when descent or rescue is impossible or even simply delayed.

The utility of bone scintigraphy with SPECT/CT in the evaluation and management of frostbite injuries.

OBJECTIVE:: Frostbite is a localized cold-thermal injury resulting from prolonged exposure of flesh to freezing and near freezing temperatures. The depth and extent of frostbite injuries are not easily assessed, from a clinical standpoint, at the time of injury making it challenging to plan appropriate management and treatment. METHODS:: A review of the literature of management of cold-related injuries and retrospective case review of the imaging and clinical course of frostbite injury. RESULTS:: Bone scintigraphy with single photon emission computed tomography (SPECT)/CT was performed in the acute and subacute course of frostbite injuries, subsequently leading to earlier definitive management and shorter hospital stay. CONCLUSION:: Multiphase technetium-99m-methylenediphosphonate (99mTc-MDP) bone scintigraphy with SPECT/CT can expedite clinical management of frostbite injuries by determining the extent of injury and can accurately predict the level of amputation if needed. ADVANCES IN KNOWLEDGE::  SPECT/CT is underutilized at many facilities but can have a profound and immediate impact on clinical management of patients with frostbite when used in combination with physiological bone scan imaging.

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.

Frostbite: management update / Actualización en el manejo de las congelaciones

The popularity of winter sports is leading to an increase in the number of subjects exposed to environmental pathologies such as frostbite. This is the reason why the patient's profile is changing from the classical descriptions of adults with preexisting conditions, basically those with cognitive impairment that prevented them from a proper protection against cold or as an occupational illness in working routines related with low temperature exposures. Nowadays these disorders occur mainly in healthy athletic young patients who expose themselves voluntarily to the cold environment, both for professional or amateur aims. Frostbite can occur as a single pathology or can take part in a more complex clinical picture that includes more serious conditions, as hypothermia or trauma. In addition to this fact, it is not uncommon that frostbite appears in exhausted and dehydrated subjects. The likelihood of such injuries taking place in remote areas further complicates its management, primarily because of the delay in diagnosis and definitive treatment. Sequelae after frostbite are common and potentially limiting for the posterior sports career. In recent years, efforts have been made to establish algorithms intended for rescue and expedition doctors to manage mountain medical care based on scientific evidence. Current recommendations include prompt identification and immediate medical care, followed by early hospital treatment if necessary and specific long-term rehabilitation programmes. This review attempts to describe current knowledge of the physiopathology and the clinical aspects of frostbite, in addition to new management perspectives, from in-situ emergency care through to hospital treatment

La popularidad de los deportes de montaña conlleva que cada vez haya más individuos expuestos a patologías ambientales como son las congelaciones. De esta forma, el perfil de los pacientes está variando respecto a las descripciones clásicas, donde se consideraban lesiones propias del adulto con patología de base, principalmente alteraciones cognitivas que le impedían protegerse adecuadamente del frío, o bien como una enfermedad laboral en profesiones relacionadas con la exposición a las bajas temperaturas. Actualmente esta patología se presenta más frecuentemente en jóvenes sanos y deportistas que se exponen voluntariamente al ambiente frío para la práctica deportiva. Las congelaciones pueden presentarse como una patología aislada o formando parte de un cuadro clínico más complejo, que puede incluir la hipotermia o patología traumática. Añadido a este hecho, es frecuente que se presenten en individuos debilitados por la fatiga y la desnutrición. La posibilidad de que esta patología tenga lugar en entornos remotos añade complejidad a su manejo y empeora el pronóstico debido al retraso del tratamiento definitivo. Las secuelas tras las congelaciones son frecuentes y potencialmente limitantes para la práctica deportiva posterior. En los últimos años se han hecho esfuerzos para basar los algoritmos de actuación de las patologías de montaña en la evidencia científica, destinados tanto al público deportivo como al personal sanitario. En síntesis, estos versan en la identificación y tratamiento inicial tempranos seguidos de tratamientos hospitalarios administrados de forma precoz en caso de ser necesarios y programas de rehabilitación específicos y prolongados. La presente revisión trata de describir las recomendaciones actuales, desde la identificación y clasificación de las congelaciones hasta los nuevos avances en el manejo sobre el terreno, médico inicial y hospitalario de las mismas

[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.

Sunburn, Thermal, and Chemical Injuries to the Skin.

Sunburn, thermal, and chemical injuries to the skin are common in the United States and worldwide. Initial management is determined by type and extent of injury with special care to early management of airway, breathing, and circulation. Fluid management has typically been guided by the Parkland formula, whereas some experts now question this. Each type of skin injury has its own pathophysiology and resultant complications. All primary care physicians should have at least a basic knowledge of management of acute and chronic skin injuries.

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.

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.

Mount Everest and Makalu cold injury amputation: 40 years on.

Freezing cold injuries (frostbite) of the extremities are a common injury among alpinists participating in high altitude expeditions, particularly during inclement weather conditions. Anecdotally, a digit that has suffered frostbite may be at greater risk to future cold injuries. In this case study, we profile a 62-year-old elite alpinist who suffered multiple digit amputations on both his hands and foot after historic summit attempts on Makalu (8481 m) and Mt. Everest (8848 m) in 1974-1979. We describe the clinical treatment he received at that time, and follow up his case 40 years after the first incidence of frostbite utilizing a noninvasive evaluation of hand and foot function to a cold stress test, including rates of re-warming to both injured and non-injured digits. Finger rates of recovery to the cold stress test were not different (0.8 vs. 1.0°C·min(-1)) except one (injured, left middle finger, distal phalanx; 0.4°C·min(-1)). Toe recovery rates after cold-water immersion were identical between previously injured and non-injured toes (0.2°C·min(-1)). Thermocouple data indicate that this alpinist's previous frostbite injuries may not have significantly altered his digit rates of re-warming during passive recovery compared to his non-injured digits.