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At least 19 recordsLinked to original sources

The value of technetium 99 scintigraphy in the prognosis of amputation in severe frostbite injuries of the extremities: A retrospective study of 92 severe frostbite injuries.

We report a retrospective study of the prognostic value of 2-phase technetium 99m bone scanning performed in 92 patients who presented to Chamonix Hospital with severe frostbite of the extremities in the past 12 years. The results of this study show that an initial bone scan (as early as day 3) has excellent specificity in evaluating the severity of frostbite injury. There was a direct correlation between the demarcation zone of uptake in the phalanges and the eventual level of amputation (positive predictive value, 0.84). A second scan on approximately day 7 was even more sensitive and informative. A strong correlation existed between positive uptake and eventual healing (negative predictive value, 0.99). This study showed that (99m)Tc bone scanning in the first few days after frostbite injury indicates the level of amputation in severe frostbite in more than 84% of cases. We propose an algorithm based on the results of this study that can be used to evaluate new medical and surgical management of frostbite injury.

Adult↗

Frostbite and bone scanning: the use of 99m-labeled phosphates in demarcating the line of viability in frostbite victims.

Early diagnosis of the extent of bone and soft tissue damage is a very important step in treating a frostbite victim. The diagnostic use of Tc-99m-phosphates in assessing the viability of soft tissue and bone in frostbite was evaluated in the early post-thaw period. Four patients were treated with a combination of warm baths, rehydration, vasodilators, epidural block, fasciotomy, and debridement. Six scans were done to stage involvement. In three of the four cases, final involvement could be determined as early as the third day. When a specific level of soft tissue or bone uptake was determined, future scanning showed either improvement, or no change in three of the four patients. In our experience, Tc-99m-phosphate scans represent an improvement over other diagnostic tests for viability of tissues.

Adult↗

[Experimental study of the pathogenesis of frostbite. Part III. Significance of energy status of muscle tissue in the pathogenesis of frostbite].

The authors have investigated energy status of muscle tissue of the lower legs of Wistar rats subjected to freezing, as well as the dependence of ultrastructure changes in muscle tissue mitochondria on the intensity of freezing. The animals were divided into three experimental groups: two groups were exposed to cryoinjury of different intensity, while the third was the control one. Cryoinjury was applied over an experimental after thawing were taken samples of muscle tissue for the analysis of content of energy phosphates and carbohydrates' metabolites, respectively, as well as for morphometric analysis of mitochondria volume out of frozen right and unfrozen left lower legs. Results obtained from different experimental groups were compared mutually and with control group that was not exposed to cryoinjury, respectively. It was found that the freezing in muscle tissue caused hydrops degeneration of mitochondria, depletion of energy reserves, reduction of energy status and the activation of mechanism of anaerobic metabolism. All these alterations were proportional to the intensity of freezing and considerably influenced contractility function of muscle cells, causing prolonged spasm of arterioles in thawed tissue, i.e., rigor congelationis that was primarily defined as an important factor in the pathogenesis of ischemic impairment of thawed tissues.

Animals↗

Experimental and clinical observations on frostbite.

Experimental ischemia by the classic frostbite rabbit ear model clearly defined the role of thromboxane as a mediator of progressive dermal ischemia in frostbite injuries. The therapeutic groups consisted of the antiprostanoids, methylprednisolone, and aspirin combined with anti-thromboxane agents Aloe vera and methimazole, while the control group received no therapy. Survival was measured by planimetry for all groups. No tissue survival was evident in the frostbite control group. Methimazole treatment allowed 34.3% survival, Aloe vera 28.2% survival, aspirin 22.5% survival, and methylprednisolone 17.5% survival. The data compare the results of a modified frostbite protocol using ibuprofen with therapeutic modalities used by other clinical services. Of 154 patients treated for frostbite from 1982 to 1985, 56 were treated with our frostbite protocol; 98 were treated with other modalities. Of the 56 protocol patients, 18 suffered 1st degree frostbite, 25, 2nd degree frostbite, and 13, 3rd degree frostbite. For all degrees of frostbite, 67.9% healed without tissue loss, 25.0% healed with partial tissue loss, and 7% required amputation (P less than .001). Of the patients not on protocol, 11 suffered 1st degree frostbite, 51, 2nd degree frostbite, and 36, 3rd degree frostbite. Of these, 32.7% healed without tissue loss, 34.6% healed with tissue loss, and 32.7% required amputation. The morbidity of progressive dermal ischemia in frostbite may be decreased by the therapeutic use of inhibitors of the arachidonic acid cascade.

Adolescent↗

Frostbite of the face and ears: epidemiological study of risk factors in Finnish conscripts.

OBJECTIVE: To determine the incidence of and the risk factors for local cold injuries of the face and ears in peacetime military service. DESIGN: Prospective, controlled epidemiological study using a questionnaire. SETTING: Finnish defence forces, 1976-89. SUBJECTS: 913 young male conscripts with local frostbite of the head that needed medical attention and 2478 uninjured control conscripts. MAIN OUTCOME MEASURES: Type of activity, clothing, and other risk factors at the time of cold injury. Odds ratios were used to calculate risk. Controls were handled as one group. RESULTS: The mean annual incidence of frostbite was 1.8 per 1000 conscripts. Frostbite of the ear was most common (533 conscripts (58%)), followed by frostbite of the nose (197 (22%)) and of the cheeks and other regions of the face (183 (20%)). Most conscripts (803 (88%)) had mild or superficial frostbite. Risk factors included not wearing a hat with earflaps (odds ratio 18.5 for frostbite of the ear); not wearing a scarf (odds ratio 2.1 and 3.8 for frostbite of the ear and cheeks respectively); using protective ointments (odds ratio 3.3, 4.5, and 5.6 for frostbite of the cheeks, ear, and nose respectively); being extremely sensitive to cold and having hands and feet that sweat profusely (odds ratio 3.5 for frostbite of the nose); and being transported in the open or in open vehicles under windy conditions (odds ratio 2.2 for frostbite of the cheek). CONCLUSIONS: Wearing warm clothing, including a scarf and a hat with earflaps, helps to prevent frostbite. Each person's sensitivity to cold may also be important. The routine use of protective ointments should not be recommended.

Adult↗

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%.

Adolescent↗

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.

Adult↗

Immediate treatment of frostbite using rapid rewarming in tea decoction followed by combined therapy of pentoxifylline, aspirin & vitamin C.

BACKGROUND & OBJECTIVES: Frostbite, the severest form of cold injury is a serious medical problem for our Armed Forces operating in the snow bound areas at high altitude. Effects of treatment by rapid rewarming in tea decoction followed by combined therapy of pentoxifylline, aspirin and vitamin C were evaluated in amelioration of tissue damage due to experimentally induced frostbite in rats. METHODS: Experiments were conducted in 2 groups (25 each) of albino rats (control i.e., untreated and experimental i.e., treated). Frostbite was produced experimentally in all the animals by exposing one of the hind limbs at -12 +/- 1 degree C with wind flow 25-30 lit/min for 30 min in a freezing-machine, with simultaneous recordings of rectal and ambient temperatures. The degree of tissue damage was assessed after 10 days. Following cold exposure, neither external thawing nor any medication was given to the animals of the control group; while the exposed limb of the experimental animals was rewarmed in tea decoction maintained at 37-39 degrees C for 30 min immediately after cold exposure, with simultaneous oral ingestion of warm tea decoction. These animals were also given pentoxifylline (40 mg/kg), aspirin (5 mg/kg) and vitamin C (50 mg/kg) twice daily orally for the next 7 days. RESULTS: In the control group, 68 per cent animals suffered from severe (56%) to very severe (12%) frostbite, while the remaining 32 per cent had moderate frostbite. No animals of this group could escape injury or suffered anything less than moderate frostbite; whereas 52 per cent of experimental animals escaped injury (no frostbite) and 32 and 16 per cent suffered only with primary and moderate degree of injury, respectively. None from this group suffered from severe or very severe frostbite. INTERPRETATION & CONCLUSION: It is evident from the study that this combined therapy resulted in significant improvement in the degree of tissue preservation and proved to be highly beneficial as an immediate treatment of frostbite in rats. The combined pharmacological properties of these drugs might have altered the haemorrheologic status of blood and produced curative beneficial effect in improving tissue survival. Clinical studies are required for confirmation of these beneficial effects in humans, which has already been taken up.

Animals↗

Diagnosis, characterisation and evaluation of treatment response of frostbite using pertechnetate scintigraphy: a prospective study.

No large prospective study is available on use of a radionuclide method to assess frostbite and its response to conservative treatment. Recently, a large retrospective study using two-phase bone scintigraphy suggested that non-uptake (or low uptake) in frostbite lesions in the blood pool or bone phase had a strong correlation with the subsequent need for amputation. In the present study, we performed early blood pool scintigraphy with technetium-99m pertechnetate in 20 patients (10-180 days after frostbite injury; 71 clinical lesions) referred for a topical treatment protocol for mild to moderately severe frostbite, and in 22 asymptomatic controls. The aims of the study were to define the "normal" microcirculation of the hands and feet, to characterise the appearances of frostbite lesions on scintigraphy and correlate these with the clinical presentation, and to evaluate the usefulness of scintigraphy for assessing the treatment response. Six patients were "fresh", 12 had been undergoing conservative treatment (topical homeopathic) for several weeks and two had permanent fibrotic hand phalanges. Nine patients on treatment underwent serial scintigraphy a total of 22 times. Eleven patients were imaged only once, including the two with permanent fixed defects. Three distinct physiological microcirculation patterns were evident in control hands or feet: right- or left-handedness (seven subjects), subclinical inflammatory foci correlating with callosity or pressure points (36 lesions) and distinctly increased pooling of radiotracer at the thenar or hypothenar region (eight subjects). In frostbite patients, 128 lesions (48 inflammatory, 80 ischaemic) were seen on the scan. This number included all 71 lesions identified clinically, the rest being subclinical. Subclinical frostbite lesion as an entity has not been described previously. Microvasculature of normal muscle groups (in the hands, elbow or feet) was shown on scintigraphy to improve after topical treatment. The treatment resulted in improved or normalised perfusion scan in 25 of 45 ischaemic segments with matching clinical improvement, and reduction or normalisation of uptake in inflammatory lesions (n=30). The data confirm the vasodilator and anti-inflammatory action of the topical preparation, and the sensitivity of the radionuclide method in monitoring treatment response. In contrast to the previous findings that non-uptake on a scan performed 2 or more weeks after exposure correlates with the need for amputation, none of the 80 ischaemic lesions in our series required amputation while 60% showed improvement or normalisation in microvascular blood flow even though they were 10-180 days old. Our findings suggest that moderate to severe frostbite lesion can be classified as having infarcted, ischaemic or hibernating (viable) tissue, similar to the classification employed when using myocardial scintigraphy. Absence of uptake even after the initial 10 days does not necessarily indicate infarction and the need for amputation as many such lesions retain potential for vasodilation and recovery.

Adolescent↗

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 Temperature↗

[Effect of frostbite under hypoxia on microcirculatory perfusion in rats].

Changes of microcirculatory perfusion in rats following cold injury of right hind leg under hypoxia were investigated. Male Wistar rats weighing 200 +/- 20 g were randomly divided into three groups: frostbite at normoxia (FN) group; frostbite during acute hypoxia (4 h at 6000 m simulated altitude, FAH) group and frostbite during hypoxia after acclimation (exposure to hypoxia at 6000 m, 4 h daily for 4 weeks, FHAC) group. The results showed that the microcirculatory perfusion of both hind legs decreased markedly in FN after cold injury. It suggests that the frostbite damage can affect microcirculatory perfusion of another leg besides the region of frostbite. The fall of microcirculatory perfusion before freezing in FAH group indicated that there was a compensatory blood redistribution during acute hypoxia. The changes of microcirculatory perfusion in FAH group post-freezing indicated that acute hypoxia can aggravate the frostbite damage. The microcirculatory perfusion of FHAC group pre-freezing was significantly lower than that of FN and FAH group, and after freezing the perfusion of frostbitten leg in FHAC group was significantly lower than that in FN group, suggesting that hypoxia acclimation may cause disturbance of microcirculation and worsen the frostbite damage at high altitude.

Acclimatization↗

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.

Absenteeism↗