Abstract and Introduction
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.
Frostbite is a localized cold thermal injury from exposure to temperatures low enough to cause ice crystal formation in tissues, resulting in damage to cell membranes and osmotically dehydrated cells. The feet and hands are the most commonly affected areas and account for 90% of frostbite injuries. Historically, frostbite was primarily seen in military populations, but it has become increasingly prevalent in homeless people, who are vulnerable to cold injuries. Additionally, a growing interest in outdoor activities, such as skiing, hiking, and mountaineering, has contributed to an increased prevalence of frostbite injuries in the general population.
Frostbite occurs because of 3 interlinked processes: (1) extracellular ice crystal formation as a direct injury, which (2) leads to oncotic fluid shifts and intracellular dehydration, and (3) ultimately cell death. The indirect injury by cold-induced vasoconstriction increases blood viscosity, microvascular thrombosis, and resultant tissue hypoxia, and this begets the final process of the release of potent inflammatory hypoxia-related mediators during the hunting reaction and with tissue reperfusion. These mediators, such as prostaglandin F2α and thromboxane A2, trigger further vasoconstriction, platelet aggregation, and blood vessel thrombosis, leading to more endothelial cell damage and further hypoxia and cell death.[3–5]
The mainstay of frostbite treatment protocol is derived from McCauley et al, which prescribed admission to hospital, rapid rewarming with water immersion at 104°F to 108°F (40°C to 42°C), tetanus prophylaxis, ibuprofen for anti-inflammatory properties, narcotic analgesics for pain control, smoking cessation, limb elevation, rest, and splinting. Since then, few major modifications in frostbite management have been introduced. Adjunctive therapies, such as early intra-arterial thrombolysis, have recently come into favor with promising results. Thrombolytic therapy has been used in frostbite injuries to limit ischemic effects by improving perfusion to affected tissues. This therapy has been shown to be effective if administered within 24 hours after rewarming frostbitten tissue.
Hyperbaric oxygen therapy (HBOT) treats patients with 100% oxygen at greater than 1.0 atmosphere (atm). It can be used to treat selected ischemic problem wounds, wounds caused by radiation, compromised flaps and grafts, and ischemia-reperfusion disorders. Hyperbaric oxygen therapy in a delayed setting (>24 hours) prevents complications of nonhealing wounds (eg, infection) and aids in demarcation. Studies have demonstrated improvement in graft survival from administration of HBOT before and after skin grafting. Other animal studies also support the use of HBOT in flap and graft compromise.
Hyperbaric oxygen therapy has been shown to mitigate reperfusion injuries by temporarily inhibiting neutrophil β2 integrins and inducing activity of antioxidant enzymes and anti-inflammatory proteins. As a therapy for frostbite, HBOT compensates for some microcirculatory failure and tissue hypoxia by increasing oxygen delivery to ischemic tissues directly via elevated arterial oxygen concentration and indirectly via angiogenesis and resolution of tissue edema. It also has demonstrated additional physiologic effects that may promote healing of frostbite injuries.
Hyperbaric oxygen therapy has been used as an adjunctive therapy for frostbite for more than 50 years. Both animal studies and human case reports have described favorable results with the use of HBOT in frostbite injuries.[11–15] However, previous reports of HBOT for this indication have been limited by small sample sizes, with the highest reported cohort being 10 patients. To further the research in this area, the authors aimed to describe the usage patterns, side effects, and outcomes of HBOT at the pediatric and adult institutions of a major Canadian university hospital.
Wounds. 2019;31(12):322-325. © 2019 HMP Communications, LLC