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.

Armed Forces Health Surveillance Division. 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.

Biopsychosocial factors associated with complications in patients with frostbite

Cold weather injuries can be devastating and life changing. Biopsychosocial factors such as homelessness and mental illness (especially substance use disorders [SUDs]) are known risk factors for incurring frostbite. Based on clinical experience in an urban level 1 trauma center, we hypothesized that complications following frostbite injury would be influenced by homelessness, SUDs, and other forms of mental illness. The aim of this study was to examine the relationship between biopsychosocial factors and both amputations and unplanned hospital readmissions after cold injuries. Patients admitted with a diagnosis of frostbite between the winters of 2009 and 2018 were included in this retrospective cohort study. Descriptive statistics and multivariable regression assessed factors associated with outcomes of interest. Of the 148 patients in the study, 40 had unplanned readmissions within 1 year. Readmitted patients were significantly less likely to have a stable living situation (48.7% vs 75.0%, P = .005) and more likely to have an SUD (85.0% vs 60.2%, P = .005) or other psychiatric disorder (70.0% vs 50.9%, P = .042). Homelessness and SUDs were independent predictors of unplanned readmission. Overall, 18% of frostbite injuries resulted in amputation. Any history of drug and/or alcohol use independently predicted amputations. The study results suggest that additional hospital and community resources may need to be marshaled to prevent vulnerable patients with biopsychosocial risk factors from having complications after frostbite. Complications place a high downstream burden on healthcare systems. Clinicians caring for frostbite patients with comorbid conditions can use these findings to inform care and discharge decisions.

Review of our 10 years experience in cold burns at the burn center in the Southeast Anatolia region of Turkey

BACKGROUND

Frostbite injuries remain to be one of the most complex and current problems of emergency medicine. Although cold burns are less frequent in hot climatic regions, it is a trauma, especially for men in our region. Also, most of the patients have difficulties in gaining early access to health and burn centers.

METHODS

We performed a retrospective analysis on sixteen patients aged between 13 and 82, who were presented to Gazi Yaşargil Training and Research Hospital Burn Center due to frostbite injuries. Data of each patient, including age, gender, injury time, extremity injuries, bacteriological observations, and general warming, were obtained from patients' files and computer records.

RESULTS

After providing the first intervention to all the patients with trauma, a circulatory disorder of the injury area was deter-mined, and the treatment was provided accordingly. The treatment of these patients required very long and expensive operations, which often resulted in making them disabled.

CONCLUSION

Deep frostbites in the cold winter months are frequently observed due to the unconscious use of ice and illegal crossings from the mountains at the Turkey border.

Update: Cold weather injuries, active and reserve components, U.S. Armed Forces, July 2016-June 2021

From July 2020 through June 2021, a total of 539 members of the active (n=469) and reserve (n=70) components had at least 1 medical encounter with a pri­mary diagnosis of cold injury. The crude overall incidence rate of cold injury for all active component service members in 2020–2021 (35.4 per 100,000 person-years [p-yrs]) was higher than the rate for the 2019–2020 cold season (27.5 per 100,000 p-yrs). In 2020–2021, frostbite was the most common type of cold injury among active component service members in all 4 services. Among active component members during the 2016–2021 cold seasons, overall rates of cold injuries were generally highest among male service members, non-Hispanic Black service members, the youngest (less than 20 years old), and those who were enlisted. The number of cold inju­ries associated with overseas deployments during the 2020–2021 cold season (n=10) was the lowest count during the 5-year surveillance period. Immersion foot accounted for half (n=5) of the cold weather injuries diagnosed and treated in service members deployed outside of the U.S. during the 2020–2021 cold season.

Management of severe frostbite with iloprost, alteplase and heparin: a Yukon case series

BACKGROUND

We identified the need to modernize frostbite management in our northern centre and implemented a treatment protocol in 2015. Our aim was to describe the clinical course of patients presenting to the hospital since the implementation of the protocol.

METHODS

This was a retrospective case series from Whitehorse General Hospital, Whitehorse, Yukon Territory, Canada. We reviewed the charts of patients who presented to the hospital with grade 2-4 frostbite and were treated as per our protocol between Feb. 9, 2015, and Feb. 8, 2020. Patients with grade 2-4 frostbite received iloprost; in addition, those with grade 4 frostbite received alteplase and heparin. We determined the number of digits affected and salvaged, and the time from presentation to the emergency department to treatment initiation. We also examined patients' demographic characteristics, predisposing events, frostbite severity and adverse drug reactions.

RESULTS

In 22 patients treated for grade 2-4 frostbite, 142 digits were affected: 59 with grade 2 frostbite, 25 with grade 3 frostbite and 58 with grade 4 frostbite; of the 142, 113 (79.6%) were salvaged. All 29 digits amputated had grade 4 frostbite. The mean time from presentation to iloprost initiation was reduced from 32.9 hours in 2015 to 3.0 hours in 2020. Sports (10 cases [45%]) and alcohol use (6 [27%]) were the most common precipitating events, with alcohol use tending to result in more severe injury (grade 4 in 5 of 6 cases). Adverse reactions with iloprost (e.g., headache) were common but mild. Adverse reactions with alteplase (e.g., bleeding) were less common but of greater clinical significance.

INTERPRETATION

Over the study period, our protocol contributed to improvement in frostbite care at our institution, resulting in a digit salvage rate comparable to other published results. Our 5-year experience shows that advanced medical care of frostbite can be achieved, even at a rural centre.

Armed Forces Health Surveillance Division. Update: Cold Weather Injuries, Active and Reserve Components, U.S. Armed Forces, July 2015-June 2020

From July 2019 through June 2020, a total of 415 members of the active (n=363) and reserve (n=52) components had at least 1 medical encounter with a primary diagnosis of cold injury. The crude overall incidence rate of cold injury for all active component service members in 2019-2020 (27.4 per 100,000 person-years [p-yrs]) was lower than the rate for the 2018-2019 cold season (35.1 per 100,000 p-yrs) and was the lowest rate during the 5-year surveillance period. In 2019-2020, frostbite was the most common type of cold injury among active component service members in all 4 services. Among active component members during the 2015-2020 cold seasons, overall rates of cold injuries were generally highest among males, non-Hispanic black service members, the youngest (less than 20 years old), and those who were enlisted. The number of cold injuries associated with overseas deployments during the 2019-2020 cold season (n=10) was the lowest count during the 5-year surveillance period. Frostbite accounted for three-fifths (n=6; 60.0%) of the cold weather injuries diagnosed and treated in service members deployed outside of the U.S during the 2019-2020 cold season.

Frostbite: Pathophysiology, Epidemiology, Diagnosis, Treatment, and Prevention

Frostbite can occur during cold-weather operations when the temperature is <0°C (<32°F). When skin temperature is =-4°C (=25°F), ice crystals form in the blood, causing mechanical damage, inflammation, thrombosis, and cellular death. Lower temperatures, higher wind speeds, and moisture exacerbate the process. The frozen part or area should not be rewarmed unless the patient can remain in a warm environment; repeated freeze/thaw cycles cause further injury. Treatment involves rapid rewarming in a warm, circulating water bath 37°C to 39°C (99°F-102°F) or, if this is not possible, then contact with another human body. Thrombolytics show promise in the early treatment of frostbite. In the field, the depth and severity of the injury can be determined with laser Doppler ultrasound devices or thermography. In hospital settings, bone scintigraphy with single-photon emission computed tomography (SPECT) 2 to 4 days postinjury provides detailed information on the depth of the injury. Prevention is focused primarily on covering exposed skin with proper clothing and minimizing exposure to wind and moisture. The Generation III Extended Cold Weather Clothing System is an interchangeable 12-piece clothing ensemble designed for low temperatures and is compatible with other military systems. The Extreme Cold Vapor Barrier Boot has outer and inner layers composed of seamless rubber with wool insulation between, rated for low temperatures. The Generation 3 Modular Glove System consists of 11 different gloves and mitts with design features that assist in enhancing grip, aid in the use of mobile devices, and allow shooting firearms. Besides clothing, physical activity also increases body heat, reducing the risk of frostbite.

Amputation Risk Factors in Severely Frostbitten Patients

In recent years, the incidence of frostbite has increased among healthy young adults who practice winter sports (skiing, mountaineering, ice climbing and technical climbing/alpinism) at both the professional and amateur levels. Moreover, given that the population most frequently affected is healthy and active, frostbite supposes a substantial interruption of their normal activity and in most cases is associated with long-term sequelae. It particularly has a higher impact when the affected person’s daily activities require exposure to cold environments, as either sports practices or work activities in which low temperatures are a constant (ski patrols, mountain guides, avalanche forecasters, workers in the cold chain, etc.). Clinical experience with humans shows a limited reversibility of injuries via potential tissue regeneration, which can be fostered with optimal medical management. Data were collected from 92 frostbitten patients in order to evaluate factors that represent a risk of amputation after severe frostbite. Mountain range, years of expertise in winter mountaineering, time elapsed before rewarming and especially altitude were the most important factors for a poor prognosis.

Armed Forces Health Surveillance Branch. Update: Cold weather injuries, active and reserve components, U.S. Armed Forces, July 2013-June 2018

From July 2017 through June 2018, a total of 478 members of the active (n=402) and reserve (n=76) components had at least one medical encounter with a primary diagnosis of cold injury. The crude overall incidence rate of cold injury for all active component service members in 2017-2018 was 19.6% higher than the rate for the 2016-2017 cold season and was the highest rate since the 2013-2014 season. Frostbite was the most common type of cold injury among active component service members in 2017-2018. Among active component members during the 2013-2018 cold seasons, overall rates of cold injuries were generally highest among males, non-Hispanic black service members, the youngest (less than 20 years old), and those who were enlisted. As noted in prior MSMR updates, the rate of all cold injuries among active component Army members was considerably higher in females than in males due to a much higher rate of frostbite among female soldiers. The numbers of cold injuries associated with overseas deployments have fallen precipitously in the past three cold seasons and included 17 cases in the most recent year.

Frostbite in the Norwegian Armed Forces

BAKGRUNN

Det finnes lite forskning på forekomst av frostskader, både sivilt og militært. Prognosen og tidsforløpet ved slike skader har ikke tidligere vært undersøkt i større kohorter.

MATERIALE OG METODE

Deltagerne var personer registrert i Forsvarets helseregister med kulde- og frostskade i tidsrommet 1.1.2010-31.12.2014. Data om diagnostikk, forløp og behandling ble innhentet fra i alt 460 personer ved hjelp av et spørreskjema. Svarprosenten på undersøkelsen var 66.

RESULTATER

397 av 460 personer (86,3 %) som var registrert med frostskade i Forsvarets helseregister bekreftet at de hadde hatt en kulde- og frostskade. 123 av 397 personene som svarte (30,1 %) anga at de hadde hatt blemmer, noe som gir mistanke om at de hadde pådratt seg annengrads frostskade. 225 av 397 (56,7 %) anga at de hadde hatt frostskade, men ikke blemmer. De aller fleste fikk frostskaden under feltøvelse/vinterøvelse (81,1 %), og ⅔ av de som pådro seg skader var vernepliktige. Langt de fleste hadde skader på fingre/hender eller tær/føtter (96,0 %). To av tre (69,8 %) hadde fortsatt plager fra sin frostskade mer enn to år etter skadetidspunktet.

FORTOLKNING

Mange i militæret pådrar seg frostskader under tjenestegjøring. En femdel anga kroniske helseplager som påvirker arbeidsevnen. Kunnskap om forekomsten av frostskader hos militært mannskap er viktig for Forsvarets videre skadeforebyggende arbeid.

Burns and frostbite in the Red Army during World War II

The start of World War II (WWII) led to the deployment of combat troops in several continents. Destruction and many casualties among both the military and civilians became an inevitable consequence. A large amount of people injured were in need of life-saving treatment and a speedy return to duty. Intensive studies of the specific issues of diagnosis and treatment of thermal injury were conducted in the Soviet Union before the war. The first special units for patients with burn injuries were created, and the first specialists received their first clinical experience. The contributions of famous Soviet scientists in the development of the treatment of burns and frostbite in WWII are studied in this article. The structure of thermal injuries among military personnel and the results of their treatment are shown. Treatment, classification and quantity frostbite in the structure of sanitary losses during the WWII are studied in this article.

Update: cold weather injuries, active and reserve components, U.S. Armed Forces, July 2009-June 2014

From July 2013 through June 2014, the number of active and reserve component service members treated for cold injuries (n=719) was the highest of the past five cold seasons (2009-2014). The rate of cold injury among active component personnel was also the highest of the 5-year period. Army personnel accounted for the majority (62%) of cold injuries. Frostbite was the most common type of cold injury in each of the services. Consistent with trends from previous cold seasons, service members who were female, younger than 20 years old, or of black, non-Hispanic race/ethnicity tended to have higher cold injury rates than their respective counterparts. Numbers of cases in the combat zone have decreased in the past 2 years, presumably as a result of declining numbers of personnel exposed and the changing nature of operations. The increase in numbers and the geographic distribution of cold injuries in the previous cold season are compatible with the unusual pattern of cold weather that marked Winter 2013-2014.

Armed Forces Health Surveillance Center (AFHSC). Cold weather injuries, active and reserve components, U.S. Armed Forces, July 2008-June 2013

From July 2012 through June 2013, the number of active and reserve component service members treated for cold injuries (n=479) was the lowest of the last five cold seasons (2008-2013). Over the last five years hypothermia was the most common cold injury among service members in the Marine Corps and Coast Guard, while frostbite was the most common type of cold injury in the other three Services. Consistent with trends from previous cold seasons, service members who were female, less than 20 years old, or of black, non-Hispanic race/ethnicity tended to have higher cold injury rates than their respective counterparts. Among service members overall, Army personnel accounted for the majority (62%) of cold injuries.

Update: Cold weather injuries, active and reserve components, U.S. Armed Forces, July 2007-June 2012

From July 2011 through June 2012, the number of active and reserve component service members treated for cold injuries (n=499) was lower than the number in each of the four previous one year periods. Over the last five years, frostbite was the most common type of cold injury in all the Services except for the Marine Corps, in which hypothermia was slightly more frequent. Service members who were female, less than 20 years old, or of black, non-Hispanic race/ethnicity tended to have higher cold injury rates than their respective counterparts. Army personnel accounted for the majority of cold injuries. Service members who train in and deploy to areas with wet and freezing conditions - and their supervisors at all levels - should be able to recognize the signs of cold injury and should know and implement the standard countermeasures against the threat of cold injury.

Frostbites in circumpolar areas

Circumpolar areas are associated with prolonged cold exposure where wind, precipitation, and darkness further aggravate the environmental conditions and the associated risks. Despite the climate warming, cold climatic conditions will prevail in circumpolar areas and contribute to adverse health effects. Frostbite is a freezing injury where localized damage affects the skin and other tissues. It occurs during occupational or leisure-time activities and is common in the general population among men and women of various ages. Industries of the circumpolar areas where frostbite occurs frequently include transportation, mining, oil, and gas industry, construction, agriculture, and military operations. Cold injuries may also occur during leisure-time activities involving substantial cold exposure, such as mountaineering, skiing, and snowmobiling. Accidental situations (occupational, leisure time) often contribute to adverse cooling and cold injuries. Several environmental (temperature, wind, wetness, cold objects, and altitude) and individual (behavior, health, and physiology) predisposing factors are connected with frostbite injuries. Vulnerable populations include those having a chronic disease (cardiovascular, diabetes, and depression), children and the elderly, or homeless people. Frostbite results in sequelae causing different types of discomfort and functional limitations that may persist for years. A frostbite injury is preventable, and hence, unacceptable from a public health perspective. Appropriate cold risk management includes awareness of the adverse effects of cold, individual adjustment of cold exposure and clothing, or in occupational context different organizational and technical measures. In addition, vulnerable population groups need customized information and care for proper prevention of frostbites.

Armed Forces Health Surveillance Center. Update: cold weather injuries, U.S. Armed Forces, July 2006-June 2011

From July 2010 through June 2011, the number of U.S. service members treated for cold injuries (n=557) was similar to recent prior years. The most frequently reported cold injury was hypothermia in the Marine Corps and frostbite in the other service branches. Cold injury rates were generally highest among service members who were less than 20 years old and of black, non-Hispanic race/ethnicity. Service members who train in wet and freezing conditions -- and their supervisors at all levels -- should know the signs of cold injury, ensure adequate hydration, and avoid tobacco, caffeine, and vasoconstrictive medications.

ENT morbidity at high altitude

BACKGROUND

People suffer unique health problems in high altitude areas, due to such factors as elevation, aircraft ascent and descent, extreme cold, hypoxia, hypobaria, and low relative humidity. This study was conducted to evaluate ENT morbidity at high altitude.

METHODS

Serving soldiers introduced to a high altitude environment who presented with various ENT symptoms were examined to identify ENT disease. In addition, patients undergoing hyperbaric chamber therapy, tracheostomy and treatment of cold injuries were also examined for ENT problems.

RESULTS

The following were detected: 13 cases of otic barotrauma, 11 cases of sinus barotrauma, three cases of vertigo, six cases of pinna frostbite, three cases of barotrauma caused by hyperbaric chamber therapy, an unusually high incidence of epistaxis, and innumerable patients with high altitude pharyngitis.

CONCLUSION

Diseases of the ear, nose and throat contribute significantly to high altitude morbidity. In a military context, health education of troops is necessary to avoid such problems.

Cold injury in the United States military population: current trends and comparison with past conflicts

OBJECTIVE

The war in Afghanistan represents the first large-scale conflict involving military troops in a cold, mountainous climate since the Korean War. An analysis was conducted to identify the extent of cold weather injuries, especially frostbite, in the deployed military population.

DESIGN

A retrospective analysis of military databases was conducted with tabulation of all cases of cold-weather injuries in Operations Enduring Freedom and Iraqi Freedom. Casualties reviewed occurred between 2001 and 2009.

SETTING

The 81st Medical Group at Keesler AFB.

PARTICIPANTS

A total of 18,214 patients reported in the Joint Theater Trauma Registry (JTTR).

RESULTS

Overall, 19 cases of cold-weather injury were identified in the Afghanistan Conflict. Two cases of frostbite were identified with only 1 likely requiring surgical intervention. No cases were identified in Iraq.

CONCLUSION

The 19 cold-weather injuries represent a dramatic decrease from the 6300 cases of cold-weather injury reported in the last major cold-weather conflict, the Korean War. This decrease results from the shorter and weather-dependent engagements, cold-weather education, and improved equipment of United States and allied personnel.

Demographics of the homeless in an urban burn unit

There are few articles about the homeless in burn literature. We sought to determine the demographic characteristics of the homeless citizens admitted to an urban burn center. This was a retrospective review from March 1999 to May 2004. Statistical analysis included chi2 and one-way analysis of variance. There were 1615 burn admissions, and 73 (4.5%) of these patients were homeless. Although the %TBSA affected was similar for the homeless and domiciled patients, the mean (+/-SD) age of the homeless was 44 +/- 10 years and their length of stay was 15 +/- 15 days, compared with 31 +/- 22 years and 9 +/- 13 days, respectively, for the domiciled. Twenty-one (29%) of the 73 homeless were admitted for frostbite, vs 21 (1.4%) of the 1542 domiciled patients (P= .000). Because of the frostbite, the majority (53%) arrived in the winter, compared with 15% in each of the other three seasons (P= .000). The homeless had a higher frequency of acute and chronic ethanol and cocaine use than the domiciled population (21% vs 6%). There was no significant difference between the homeless and the domiciled population in %TBSA affected, nutritional values, and assault frequency. More than half of the homeless patient admissions to the burn unit resulted from assault or frostbite. The homeless were mainly African-Americans and Caucasians, with a higher frequency of ethanol and cocaine use than in the domiciled burn population. Lack of discharge options for the homeless prolonged the average length of stay, leading to increased costs, often borne by the burn unit.

Frostbite: incidence and predisposing factors in mountaineers

BACKGROUND

Frostbite, the most common cold injury, occurs in mountaineers, a major group at risk, more often than in the general population.

OBJECTIVES

To describe the incidence of frostbite and the situations associated with it in mountaineering, emphasising factors that can be modified to decrease its frequency and severity.

METHODS

In this cross sectional, questionnaire based study, 637 mountaineers were asked if they had suffered any frostbite injuries during the preceding two years and to provide the personal and circumstantial details.

RESULTS

The mean incidence was 366/1000 population per year. Grade 1 injury (83.0%) and hands (26.4%) and feet (24.1%) involvement were most common. There was a significant relation between lack of proper equipment (odds ratio 14.3) or guide (p<0.001) and the injury. Inappropriate clothing, lack or incorrect use of equipment, and lack of knowledge of how to deal with cold and severe weather were claimed to be the main reasons for the injury.

CONCLUSIONS

In high altitude and winter expeditions, mountaineers should wear appropriate clothing, have the necessary equipment such as quality boots and mittens, use a competent guide, and have training on how to tackle cold weather. They should also avoid wet clothing, windy terrains, and should never remain in the same position for long periods to reduce the risk of cold injuries.

Cold injuries

Exposure to cold can produce a variety of injuries that occur as a result of man's inability to adapt to cold. These injuries can be divided into localized injury to a body part, systemic hypothermia, or a combination of both. Body temperature may fall as a result of heat loss by radiation, evaporation, conduction, and convection. Hypothermia or systemic cold injury occurs when the core body temperature has decreased to 35 degrees C (95 degrees F) or less. The causes of hypothermia are either primary or secondary. Primary, or accidental, hypothermia occurs in healthy individuals inadequately clothed and exposed to severe cooling. In secondary hypothermia, another illness predisposes the individual to accidental hypothermia. Hypothermia affects multiple organs with symptoms of hypothermia that vary according to the severity of cold injury. The diagnosis of hypothermia is easy if the patient is a mountaineer who is stranded in cold weather. However, it may be more difficult in an elderly patient who has been exposed to a cold environment. In either case, the rectal temperature should be checked with a low-reading thermometer. The general principals of prehospital management are to (1) prevent further heat loss, (2) rewarm the body core temperature in advance of the shell, and (3) avoid precipitating ventricular fibrillation. There are two general techniques of rewarming--passive and active. The mechanisms of peripheral cold injury can be divided into phenomena that affect cells and extracellular fluids (direct effects) and those that disrupt the function of the organized tissue and the integrity of the circulation (indirect effects). Generally, no serious damage is seen until tissue freezing occurs. The mildest form of peripheral cold injury is frostnip. Chilblains represent a more severe form of cold injury than frostnip and occur after exposure to nonfreezing temperatures and damp conditions. Immersion (trench) foot, a disease of the sympathetic nerves and blood vessels in the feet, is observed in shipwreck survivors or in soldiers whose feet have been wet, but not freezing, for long periods. Patients with frostbite frequently present with multisystem injuries (e.g., systemic hypothermia, blunt trauma, substance abuse). The freezing of the corneas has been reported to occur in individuals who keep their eyes open in high wind-chill situations without protective goggles (e.g., snowmobilers, cross-country skiers).

Frostbite Injuries Treated in the Helsinki Area from 1995 to 2002

BACKGROUND

: Exposure to cold results in frostbite, superficial or deeper tissue damage. In severe frostbites, amputations are life-saving but diminish quality of life (QOL).

METHODS

: Retrospective study was performed. RAND 36- questionnaire was administered to assess QOL. Our aim was to investigate risk factors and adjustment to everyday life of hospitalized patients.

RESULTS

: 92 frostbites in 42 patients were recorded. One third of the patients were chronic alcoholics. Age and temperature were statistically significant factors for unfavorable outcome. 20% of patients required secondary reconstructive procedures. One-third reported their emotional well-being very poor. Half had limitations in social life.

CONCLUSIONS

: Hospitalized cases of frostbite are rare. Anti-social behavior increases the risk in general, and patients present with complicated problems similar to those encountered in burns victims. We recommend that frostbite patients requiring hospital attendance are treated in specialized units, where sufficient expertise for acute as well as reconstructive surgery is available.

The occurrence of frostbite and its risk factors in young men

OBJECTIVES

Previous studies have paid little attention to the occurrence of frostbites and related risk factors. The purpose of this study is to analyse the life-time occurrence of frostbite in young men and its association with the cold-provoked white finger syndrome (CPWF), smoking and hand vibration.

METHODS

The study population consisted of 5839 Finnish men aged 17-30 years entering military service. Data was collected for cases of first-degree, or more severe, frostbite affecting the head and extremities. Logistic analysis was used to assess the risk of frostbite with respect to CPWF, smoking and hand vibration.

RESULTS

The life-time and annual occurrences of frostbite were 44% and 2.2%, respectively (n = 2555). 2333 subjects (41%) had suffered first-degree freezing injury and 671 (12%) suffered severe injury at some time in their lives. The sites most prone to frostbite were the head, 1668 cases (31%), followed by the hands, 1154 (20%), and the feet, 810 (15%). The risk for frostbite in different body parts was increased among the subjects with CPWF (95% CI: 1.66 to 3.87), regular smokers (95% CI: 1.02 to 3.15) and those exposed to vibration (95% CI: 1.07 to 4.03).

CONCLUSIONS

A synergistic increase of frostbite was reported between CPWF and regular smokers, and between CPWF and hand/arm vibration in both exposure classes analysed. The life-time occurrence of frostbite among young healthy men was high. Frostbite, and its association with CPWF, smoking and hand/arm vibration should be noted by the health care personnel in circumpolar countries.

Environmental-temperature injury in a Canadian metropolis

This study performed a preliminary investigation of the incidence and determinants of environmental-temperature injury among residents of Montreal Island, Quebec, Canada. Incidence rates, mortality rates and determinants of environmental-temperature injury were estimated for Montreal Island's 1,802,309 urban and suburban residents. Sources of information included coroner's reports, death certificates, hospital discharge summaries, and hospital chart reviews. The estimated incidence rate for environmental-temperature injury requiring hospitalization on Montreal Island was 3.1 per 100,000 person-years. The estimated mortality rate for all environmental-temperature injuries on Montreal Island was 0.3 per 100,000 person-years. The majority of hospitalizations and deaths were due to cold injury. Male gender, alcohol intoxication, psychiatric illness, older age, and homelessness were suggestive of important risk factors in cold injury. All deaths due to heat injury occurred in elderly females. Montreal Island's ambulance transport service, with its unique database, was identified as a novel surveillance design for environmental-temperature injury. Knowing more about the incidence and determinants of environmental-temperature injury may suggest priorities for interventions to decrease morbidity and mortality.

Epidemiology of U.S. Army cold weather injuries, 1980-1999

BACKGROUND

Cold weather injuries (CWI) are of great military concern due to their wide-ranging impact on military readiness. Previous short-term studies have identified CWI to be more prevalent in African-Americans, infantrymen, and lower-ranking soldiers. The purpose of this cross-sectional study was to determine the occurrence of CWI hospitalizations in the U.S. Army from 1980 to 1999, and to identify possible trends, high-risk groups and/or activities.

METHODS

The U.S. Army Research Institute of Environmental Medicine Total Army Injury and Health Outcomes Database was searched for hospitalizations with ICD-9-CM codes for frostbite, hypothermia, immersion foot, chilblains, and other. Information concerning each soldier included: gender, age, ethnicity, rank, occupation, type of injury, home of record, duty station, principle diagnosis, trauma code, and cause of injury. Data was available on the demographic composition of the Army, by year, and was used as the denominator when calculating the frequency of occurrence.

RESULTS

During the study period there were 2143 hospitalizations due to CWI. African-American men and women were injured approximately 4 times and 2.2 times as often as their Caucasian counterparts, respectively. Trauma and cause of injury codes indicate that about 80% of all CWI hospitalizations result on-duty and during organized training. The yearly rate of CWI hospitalization has declined from 38.2/100,000 in 1985 to 0.2/100,000 in 1999.

CONCLUSIONS

Our data are consistent with previous research concerning the increased rate of CWI among African-Americans though further investigation appears warranted. The occurrence of most CWI during on-duty training suggests preventability. The decline in the overall rate of CWI hospitalizations is multifactorial.

Hypothermia and local cold injuries in combat and non-combat situations--the Israeli experience

INTRODUCTION

Cold weather has been recognized in the Israel Defense Forces (IDF) as a potential medical and operational threat to the soldier. Although regulations have been issued to cope with this situation, every year about 20 cases of hypothermia (T(core) < 35 degrees C) and peripheral cold injuries are reported.

METHODS

This study was aimed at following cold weather injuries (CI) in the IDF in the period 1994-2001. 136 cases were reported to our institute during this period. All patients were from the general population of young (20 +/- 2 yr), male soldiers in the IDF. All were classified a priori as healthy, active subjects.

RESULTS

Of these patients, 51% were diagnosed with mild hypothermia and 49% with peripheral CI. Among those soldiers who suffered from peripheral CI, less than 5% were diagnosed with frostbite. Most of the cases (76%) occurred in the winter months; however, 10% occurred in the spring, 13% in autumn, and 2 cases (1%) were reported in the summer. The majority of all CI cases occurred during routine scheduled training (51%), and 15% occurred during routine duties. Of the cases, 34% occurred during combat operations (mainly ambushing and surveillance).

DISCUSSION

The present study provides data on CI cases in an army where the awareness of the hazards involved in hostile environments is extensive, and in which detailed regulations aimed to prevent these injuries are common practice. The Israeli experience indicates that CI is preventable in most instances by following a few simple regulations and providing proper education to the soldiers and their commanding officers.

Incidence of frostbite and ambient temperature in Finland, 1986-1995. A national study based on hospital admissions

OBJECTIVES

The association of frostbite with ambient temperature in Finland is not known. The present study determined the incidence of frostbite and its association with sex, age and ambient temperature in a nationwide sample.

STUDY DESIGN

The first admissions of all patients (n=1,275) admitted to hospital in Finland during the period 1986-1995 with frostbite as a principal or secondary diagnosis were associated with ambient temperature on the day of admission.

RESULTS

The incidence of frostbite was 2.5 per 100,000 inhabitants, it was higher in males than females and increased linearly with age. The annual incidence of frostbite started to rise at below -15 degrees C and was considerable at under -20 degrees C, particularly in northern Finland. However, the daily incidence increased most in the urban area of Helsinki.

CONCLUSION

In the north, the main factor is the large number of cold days in the year. The daily incidence may be affected by urban lifestyle, possibly fashion, and inability to protect oneself against the cold.

Changing pattern of major lower limb amputations in Seinäjoki Central Hospital 1997-2000

BACKGROUND AND AIMS

There is rather limited recent information on major amputations in Finland. Our objective was to describe the incidence of major lower limb amputations in a defined central hospital, the demographic characteristics of the amputees, diagnosis and situations leading to amputation, level of amputations and survival of the amputees after one year.

MATERIAL AND METHODS

A retrospective study was undertaken on 156 patients with 169 lower limb major amputations from 1997 to 2000 at the Seinäjoki Central Hospital and Ahtäri District Hospital.

RESULTS

The annual incidence of major amputations reduced from 29.5 to 15.2/100000 inhabitants. The mean age of the patients was 78.5 years but highest 80.1 in the year 2000. The reason for major amputation was chronic critical leg ischaemia with or without diabetes mellitus in 79.1% and acute ischaemia in 13.9%. The average below-knee (BK)/above-knee (AK) amputation ratio was 0.80 during the years 1997-1999 and the ratio was lowest 0.67 in year 2000. At the same year 2000 the amount of patients, whose condition was too poor for reconstructive surgery, was significantly higher than in 1997-1999.

CONCLUSIONS

We suggest that BK/AK amputation ratio is decreasing in the future as the amputees tend more often to be institutionalized and immobile, and reconstruction is not an alternative and BK amputation is impossible or useless.

Retrospective study of 70 cases of severe frostbite lesions: a proposed new classification scheme

OBJECTIVE

Previous frostbite classifications were mainly based on retrospective diagnosis and, most of the time, could not be used to predict the final outcome of the lesions and especially the probability of an amputation and its level. The aim of this study was to suggest a new classification at day 0 based mainly on the topography of the lesions and on early bone scan results, which are more convenient and accurate in predicting the final outcome of frostbites.

METHODS

The retrospective study of the clinical histories of 70 patients hospitalized at Chamonix Hospital (Mont-Blanc Massif) from 1985 to 1999 for severe frostbite injuries of the extremities has allowed us to classify the aspects of the initial lesions on day 0 and to compare them with final outcomes.

RESULTS

A strong correlation was found between the extent of the lesion and the outcome of each finger or toe. When the initial lesion was on the distal phalanx, the probability of bone amputation was around 1% for the digit, 31% for the middle phalanx, 67% for the proximal phalanx, 98% for the metacarpal/metatarsal, and 100% for the carpal/tarsal.

CONCLUSIONS

Based on these clinical results and on the results of bone scans (previously validated), a new classification of frostbite severity at day 0 is proposed. Four degrees of severity are defined: first degree, leading to recovery; second degree, leading to soft tissue amputation; third degree, leading to bone amputation, and fourth degree, leading to large amputation with systemic effects.

Emollients in the prevention of frostbite

47% of Finnish conscripts had had at least one frostbite of the head (42% on the ears, 23% on the face) at the age of 19. Non-medicated ointments are traditionally used in Finland for protection against facial frostbite without scientific evidence of their benefit. In studies on cold protecting emollients it was found that 21% of the male conscripts in Finland had used them in the cold. 84% of the users had experienced their effect as somewhat or clearly protective. However, in a controlled prospective epidemiological study of 913 cold injuries of the head, the use of cold protective ointments was associated with an increased risk of frostbite to the head (odds ratio 4.5 for ear frostbite, 5.6 for nasal frostbite and 3.3 for frostbite on other parts of the face). The thermal insulation provided by different emollients in the cold was minimal in in vitro experiments using a skin model. In in vivo studies with test subjects the skin on the applied half of the face cooled at least as quickly as the untreated half. However, when white petrolatum was applied, the subjective skin perception of a test persons was warming in the majority of the tests, in contrast to objective measurements. "Protecting" emollients seem to cause a false sensation of safety leading to an increased risk of frostbite probably mainly through neglect of efficient protective measures.

Frostbite: occurrence, risk factors and consequences

Frostbites affect the civilian northern population more commonly than thought earlier. Cumulative lifetime incidences may be as high as 44-68% for all types of frostbite. Incidences of frostbite have mainly been reported in association with military activities but occur also during occupational duties and in recreational situations. Frostbites often affect the extremities and especially the head region. Several different predisposing factors have been reported in relation to frostbites. These can be divided mainly into environmental, individual, behavioural and occasion-linked factors. Actual risk analyses have been conducted for a limited amount of these predisposing factors. Frostbites very often result in different functional disadvantages, some of which can lead to a temporary or permanent disability to work or carry out military duties, while others may impact negatively on occupational activities, or cause hospitalization and invalidity to varying degrees. Further, frostbites often cause sequelae lasting from a few weeks to a lifetime.

Sequelae of moderate finger frostbite as assessed by subjective sensations, clinical signs, and thermophysiological responses

The aim of the study was to investigate prevalence and qualities of sequelae following moderate finger frostbite. The study material comprised 30 subjects, who had suffered second-degree frostbite (73% contact frostbite) 4-11 years before this study. In clinical tests 66% of the subjects had an elevated tendency for vasospasm, yet only 20% suffered from white fingers. However, no marked traces of frostbite-related alterations were observed in systemic cardiovascular reflex tests or in X-ray examinations of the frostbite area. Subjective assessments revealed a high prevalence of sequelae (63%), although the primary frostbite was moderate and local. The sequelae in the frostbite area included hypersensitivity to cold (53%), numbness of fingers (40%), and declined sensitivity of touch (33%). Also working ability was lowered due to frostbite sequelae (13%). In cold air provocation tests, the skin temperature of the frostbitten areas decreased more quickly and reached lower values than in healthy control subjects. In conclusion the suffered frostbite was associated with an increased tendency for vasospasm. Subjective sensations of the frostbitten area were associated with thermophysiological changes. The sequelae were reported to worsen in the cold environment thus emphasizing the probable occupational limitations of even moderate cold injury.

Army psychiatry in the Korean War: the experience of 1 Commonwealth Division

This study seeks to investigate the incidence of psychiatric casualties in 1 Commonwealth Division during the Korean War. It had been hypothesized that these casualties were unusually low compared with earlier conflicts. Casualty returns and psychiatric reports were analyzed and showed that the war fell into two phases determined by the intensity of combat, which, in turn, influenced the nature of the psychiatric disorders encountered. Rates of acute combat stress were closely correlated with battle casualties, although not with total psychiatric admissions or nonbattle injuries. The limitations imposed on the psychiatric liaison service by the medical organization suggested that the incidence of psychosomatic cases, including cold injury, may have been unintentionally underreported.

Frostbite: pathogenesis and treatment

Frostbite, once almost exclusively a military problem, is becoming more prevalent among the general population and should now be considered to be within the scope of the civilian physician's practice. Studies into the epidemiology of civilian frostbite have identified several risk factors that may aid the clinician in the diagnosis and management of cold injuries. Research into the pathophysiology has revealed marked similarities in inflammatory processes to those seen in thermal burns and ischemia/reperfusion injury. Evidence of the role of thromboxanes and prostaglandins has resulted in more active approaches to the medical treatment of frostbite wounds. Although the surgical management of frostbite involves delayed debridement 1 to 3 months after demarcation, recent improvements in radiologic assessment of tissue viability have led to the possibility of earlier surgical intervention. In addition, several adjunctive therapies, including vasodilators, thrombolysis, hyperbaric oxygen, and sympathectomy, are discussed.

The epidemiology of skiing injuries in Antarctica

A retrospective analysis of all skiing injuries experienced by members of the British Antarctic Survey between 1989 and 1995 was undertaken to test the hypothesis that skiing was responsible for a disproportionate number and severity of injuries compared with other activities. Fifty-nine new consultations for skiing injuries were recorded. This represented 3.2% of all consultations (annual range 1.3-6.7%), or 9.7% of all consultations due to trauma. The mean incidence was 84.3/1000 population/year. The annual proportion and rate of consultation fluctuated but no overall trends were noted. The lower limb was the commonest site of injury (76.3%), with the ratio of lower limb: upper limb injuries being 6.4:1. The commonest single injury was an isolated medial collateral ligament knee sprain (23.7% of all consultations). Head injuries comprised 8.5% and ulnar collateral ligament thumb sprains 5.1%. Assessment of injury by the Injury Severity Score (ISS) showed that skiing injuries were significantly more likely to be non-trivial (ISS > 2) than work-related injuries [chi 2(1, N = 56) = 55.6, p < 0.001] or injuries of all causes [chi 2(1, N = 56) = 65.0, p < 0.001]. They were significantly more likely to need radiological investigation than all injuries [chi 2(1, N = 59) = 22.0, p < 0.001]. The most severe (ISS 13), survivable injury seen during the study period resulted from a skiing accident. This excess of non-trivial injury raises important management issues, particularly as the majority (81%) were recreational.

The epidemiology of cold injury in Antarctica

METHOD

A retrospective study was performed of 10 yr of medical records to determine the type, severity, etiological factors and treatment of cold injury experienced by members of the British Antarctic Survey between 1986-95.

RESULTS

There were 61 new consultations for cold injury. These comprised 2.5% of all new consultations with an incidence of 65.6 per 1000 per year. Cold injuries seen were frostbite (95%), hypothermia (3%) and trench foot (2%). Superficial frostbite was the most common injury (74% of cases) with the face the most frequently affected area (47% of injuries). No cases of frostbite severe enough to cause permanent tissue loss were seen. The prevalence of cold injury increased with falling temperature to a maximum between -25 and -35 degrees C, despite these temperatures occurring infrequently. The relationship with windchill is not as clear cut with frequency of injury tending to follow the frequency of windchill values except at higher windchill values. Neither temperature nor windchill were found to significantly influence the severity of frostbite. Prior cold injury was shown to be significantly (chi2 p < 0.001) associated with further cold injury. Most injuries (78%) occurred during recreation; skiing and snowmobile driving were often implicated.

CONCLUSIONS

Cold injury is uncommon in Antarctica. Despite this, it warrants a continued high profile as under most circumstances it may be regarded as an entirely preventable occurrence.

Cold protecting ointments and frostbite. A questionnaire study of 830 conscripts in Finland

Application of ointments to the face is one of many measures used to avoid frostbite of the head in cold climates. A recent epidemiological study indicated, however, that the use of ointments in the cold may be a considerable risk factor in development of frostbite of the face and ears. A questionnaire on the use of protective ointments was completed by 830 young male conscripts divided into 4 groups by climatic home region on the south - north axis of Finland. Personal estimates of cold exposure, sensitivity to cold, smoking, and cumulative incidence of frostbite to the face and ears were reported. Twenty-one percent of the conscripts had used cold protective ointments, mostly at school age or earlier. In 25% of the conscripts' families some other member (mostly women and children) had used emollients in order to prevent cold injuries. Both the conscripts and their families living in southern Finland used protective ointments more often than those in northern Finland. Almost half (47%) of the conscripts had had frostbites of the head, 42% of the ears and 23% of the face. Those who had used ointments in the cold had a significantly higher cumulative incidence of frostbites on the face (p=0.0031), especially on the cheeks and chin. Their subjective experience concerning the protective effect of ointments in the cold was somewhat or clearly positive in 84% of respondents. The controversy between subjective experience and increased incidence of facial frostbite in ointment users needs further investigation.

Cold weather injuries in an arctic environment

The cases of eight Special Forces soldiers who sustained cold weather-related injuries while conducting winter training as part of Operation Arctic Saber in the Northwest Territories and Arctic Circle are reported. Environmentally related injuries can represent difficult diagnostic and treatment challenges in the field. Moreover, they may compromise the overall mission if they are not identified and treated early. Cold weather injuries can also result in long-term disfigurement and disability that may limit a soldier's future worldwide deployability. Mission requirements, equipment utilization, and environmental exposure place soldiers at particular risk for cold weather-related injuries in such austere settings. Nonetheless, with appropriate education and safety precautions, these potentially life-threatening risks can be greatly minimized.

Frostbite: epidemiology at high altitude in the Karakoram mountains

During a 10-year period (December 1984 to December 1994), 1500 cases of frostbite were treated at a tertiary care medical facility. They were all males with their ages ranging from 17 to 43 years. All the patients sustained the frostbite injury in the northeastern part of Pakistan known as the Karakoram range of mountains. They included a large number of porters and guides employed by various mountaineering expeditions (approximately 250-300 expeditions per year) in that region, as well as local inhabitants. This retrospective study included the heights at which frostbite occurred (range 11,000-22,000 feet above sea level). Of the patients, 15% (n = 225) got frostbitten within 1 h of exposure, whereas the majority (71%) had an exposure of 1-3 h. The effect of seasonal variations (relative hypothermia) on the extent and depth (degree) of frostbite and the distribution of lesions as per body surface subunits (areas) was noted and found to be statistically significant with P < 0.05 for both. The occurrence of frostbite at various heights showed a very steep upward curve beyond a height of 17,000 feet above sea level. This has been termed the 'cut-off' point for frostbite by the authors, the increase depicting the true picture of 'high altitude frostbite'. Tobacco smoking and peripheral vascular disease were found to be important contributing factors. The feet were involved most frequently (64%) followed by the hands (32%), the head and neck region (3%) and the perineum (1%). Independent effects of the height (relative hypoxia) on the depth of frostbite lesion (degree) and on the involvement of multiple body areas (surface subunits) showed significant correlation with P values well below 0.05 for each. Of cases, 92% (n = 1386) had second- or third-degree frostbite necessitating definitive surgical intervention. Total frostbite-related mortality spanned over 10 years was 11%.

Frostbite: review and current concepts

BACKGROUND

A literature review was conducted to analyze developments in the epidemiology, pathogenesis, treatment, and prevention of frostbite injury. Increased participation in outdoor activities, as well as the epidemic of homelessness, makes knowledge of the treatment of frostbite crucial for physicians in both rural and urban areas.

METHODS

A literature search, using the key words "frostbite" and "cold," was done using MEDLINE and Index Medicus. This search focused on the epidemiology, pathogenesis, treatment, and prevention of frostbite.

RESULTS

Research done during the past 15 years has clarified the pathogenesis of frostbite injury and led to a better understanding of how to limit tissue loss. The etiology of frostbite is commonly related to alcohol use, psychiatric illness, or motor vehicle problems. The pathogenesis is linked to tissue freezing, hypoxia, and the release of inflammatory mediators. The initial clinical manifestations of frostbite injury are similar for superficial and deep tissue damage, so early treatment is identical for all injuries. Optimum therapy is based on the rapid reversal of tissue freezing by rewarming in 104-108 degrees F water and the institution of oral and topical antiprostaglandin therapy to limit the release of inflammatory mediators.

CONCLUSION

Rapid triage and treatment of frostbite can lead to dramatic improvements in outcome and prognosis. Increased awareness of antiprostaglandin therapy and preventive measures is crucial for physicians in diverse practice environments.

Cold weather injuries among U.S. soldiers in Alaska: a five-year review

Cold weather injury (CWI) reports covering 272 U.S. Army soldiers from September 1990 to May 1995 were reviewed. First- and second-degree frostbite accounted for 99.3% of all injuries. Although some soldiers had extensive lost duty time from their injuries, no one suffered tissue loss during the 5-year period. Fifty-one percent of injuries occurred during field training. Thirty-six percent occurred while engaging in garrison activities, including physical training, which accounted for 15% of all CWIs. Twelve percent of all injuries occurred during off-duty time. Seventy-one percent of CWIs occurred when the wind-chill factor was at or below -20 degrees F (-29 degrees C). Male African-American soldiers appear to be significantly more susceptible to frostbite than male Caucasian soldiers, especially with regard to frostbite of the distal extremities (relative risk = 3.94; 95% confidence interval = 2.77-5.59). Other identified risk factors include inadequate clothing, wet clothing, dehydration, inactivity, fatigue, and previous CWIs.