While snowmobiling, Jonathan Allison, a 39-year-old male, is exposed to cold temperatures for an extended time. He arrives at the emergency department complaining he has no feeling in his lower extremities.
History and assessment hints
Initial assessment reveals no sensation below the ankles. Mr. Allison’s bilateral lower extremities are cold. Capillary refill is decreased in the left lower leg and absent in the right lower leg. His pulses are nonpalpable bilaterally. Otherwise, he is healthy. He denies alcohol consumption before snowmobiling. Despite the negative initial screening for frostbite risk factors (smoking, diabetes, and recent alcohol consumption), you suspect frostbite because of his extended exposure to cold. To minimize tissue injury and help save his digits, you rapidly complete your assessment.
On the scene
Then you focus on starting the rewarming process. The patient is normothermic, so to rewarm the affected extremities, you use circulating warm water set to a temperature of 100.4° to 104° F (38° to 40° C), as ordered. The physician obtains central I.V. access and orders analgesics for pain control as the rapid response team obtains vital signs, an electrocardiogram (ECG), and laboratory samples.
Next, the patient is admitted to the burn intensive care unit for treatment and reperfusion therapy. A bone scan shows no blood flow to the feet. To help restore perfusion to his lower legs, the team immediately starts the tissue plasminogen activator (t-PA) frostbite protocol. Mr. Allison receives an initial weight-based t-PA bolus of 0.15 mcg/kg, followed by a 6-hour continuous infusion.
After the first hour of t-PA therapy, Doppler ultrasonography shows he has dorsalis pedis and posterior tibial pulses. Nursing priorities focus on rewarming the extremities and performing hourly neurovascular and vital-sign checks, ECG monitoring, and neurologic assessments. To limit further injury, you perform wound care, cleaning the affected areas and applying an antimicrobial ointment to help prevent infection. As ordered, you give oral and I.V. analgesics as needed to control pain during rewarming, which continues until the t-PA infusion is complete.
Thanks to your rapid assessment and the team’s prompt t-PA initiation, Mr. Allison regains adequate perfusion of the lower extremities, as shown by a repeat bone scan, and is able to avoid digital amputation.
Education and follow-up
Frostbite from cold exposure can severely injure the skin and underlying tissues. Freezing temperatures compromise circulation, damaging endothelial tissue and causing small clots to form in blood vessels. Ultimately, tissue death may occur. Without effective treatment, more than 40% of victims require digital amputation.
Preventing devastating effects of frostbite requires rapid nursing assessment and interdisciplinary interventions, including rapid rewarming of injured tissue, topical antimicrobial cream, antibiotics, pain management, wound care, and monitoring of digits to evaluate perfusion until amputation of the affected areas is deemed necessary. Follow-up bone scans aid evaluation of perfusion and identify areas of permanent injury.
Recent evidence suggests t-PA therapy can restore perfusion to the affected area, reducing tissue loss. Although t-PA as a frostbite treatment is off-label (unapproved), research suggests it improves revascularization by dissolving microclots and restoring tissue perfusion. Be aware that t-PA may cause bleeding and necessitates frequent neurologic assessments. Also, it must be used within 24 hours of the initial injury.
Before discharge, you provide education to Mr. Allison and his family, focusing on teaching them how to recognize frostbite signs and symptoms, such as tingling and burning of the affected area, numbness, blood-filled blisters, white or grayish-yellow skin, and unusually firm or waxy skin. You also stress the importance of seeking immediate medical attention when these occur.
The authors work at the University of Colorado Hospital in Aurora. Samantha Weimer and Linda Staubli are charge nurses in the burn trauma ICU. Mary Beth Flynn Makic is a research nurse scientist in the critical care unit.
Very well written and informative article.I think the microclots dissolving makes a lot of sense.