Case Report

Contents lists available at ScienceDirect

American Journal of Emergency Medicine

journal homepage: www. elsevier. com/ locate/ajem

Reversible common peroneal nerve palsy as a complication of therapeutic hypothermia using Surface cooling device

Abstract

peripheral neuropathy as a result of nonfreezing cold injury by ther- apeutic hypothermia (TH) is extremely rare. We report the case of a 54- year-old woman who suffered from common peroneal nerve palsy caused by inappropriate application of cooling pads for TH after ische- mic encephalopathy following hanging injury. When a cooling device is running, cold water rotates through cooling pads just above the skin. Therefore, the patient’s skin and superficial nerves, such as the common peroneal nerve, can be damaged by cold water. To prevent this complication, a proper-sized pad and proper application of the cooling pad are crucial.

The application of TH can cause several systemic and local adverse events due to a rapid core temperature drop and maintenance of hypo- thermia, which disturb a patient’s homeostasis and can cause local cold injury. Most reported complications are systemic adverse events such as cardiovascular events, infection, electrolyte imbalance, acute kidney injury, and coagulopathy [1-3]. Local adverse events are rarely reported. Nowadays [4], surface cooling with the use of surface cooling pads that are coated with hydrogel is one of most common methods to induce therapeutic hypothermia. Cooling pads adhere to the patient’s abdomen, back, and thighs, allowing for direct thermal conduction through the skin. Consequently, this method can result in superficial skin injury [5] and peripheral nerve damage. This report highlights cold-induced adverse events to the skin and peripheral nerve from the use of a surface cooling device.

A 54-year-old woman was found hanging on a towel rack, unrespon- sive in her home. When the emergency medical technician took her pulse, she had a faint pulse. She was admitted to our emergency depart- ment. She had a medical history of diabetes and alcoholic liver disease. Her height was 152 cm, and body weight was 40 kg. On arrival, blood pressure was 130/90 mm Hg; heart rate, 104 beats per minute; oxygen saturation, 96% by oxygen mask (10 L/min); and temperature, 36.8?C. On examination, she was in a stupor (Glasgow Coma Scale: 6, E1V1M4); her pupil reflex was normal. Results of head computed to- mography and simple neck radiography were normal. We performed intubation and started mechanical ventilation. To reduce hypoxic brain injury, therapeutic hypothermia was initially induced according to the standard guideline [6].

We used the surface cooling device with a medium-sized cooling pad (ARCTIC SUN 2000 temperature management System and ARCTIC GEL Pads; Medivance Inc, Louisville, CO) to decrease body temperature. We kept the patient’s core temperature at a target temperature of 33?C for 24 hours and then rewarmed the patient. When her body tempera- ture reached 36.5?C, we stopped administration of Muscle relaxants and

sedatives; and the patient recovered consciousness. After 48-hour application of the surface cooling device, we removed the cooling device from the patient.

After removal of the cooling pads, the patient complained of paresthesia over the right foot dorsum and foot-drop. Physical examination revealed erythematous and bullous skin lesions on the right knee (Figure) and weakness in dorsiflexion of the ankle and great toe extension. Nerve conduction study and electromyography revealed incomplete right common peroneal neuropathy at the knee level. Motor conduction velocity and amplitude were decreased in the right common peroneal nerve around the fibula neck (velocity of 38.3 m/s and amplitude of 0.5 mV on the right compared to 43.1 m/s and 3.7 mV on the left). Sensory nerve action potential was significantly reduced in the right superficial peroneal nerve compared to the left (amplitude of 5.9 mV on the right compared to 17.4 mV on the left). Electromyography showed evidence of marked denervation with reinnervation in the right tibialis anterior and right peroneous brevis.

The patient was treated with a foot-drop splint and a physiother- apy program. On the 14th day of hospitalization, the patient was discharged with remnant motor and sensory dysfunction. At 6-month follow-up, the patient was completely recovered without neurologic impairment.

In this case, the complication was a nonfreezing-type cold injury because the temperature of water circulating through the cooling pads did not drop below 0?C. Jianping and Pollock [7] reported an experimental study about the effects of nonfreezing cold injury on peripheral nerves. In rat models, after decreasing the temperature by 1?C to 5?C around the nerve by using a cooling device, the vasa nervorum exhibited cold- induced endothelial damage and delayed thrombotic occlusion. Clinically, during hypothermia treatment, the water temperature in the cooling pads decreases below 5?C to 10?C because the guidelines recommend that the body temperature be decreased as soon as possible. If the patient has a fever, the temperature will be even colder, resulting in further injury to patients. A previous study reported that nonfreezing cold injury such as “Trench foot” can be induced by peripheral neuropathy or skin injury [8]. Another study also reported that cryotherapy for the purpose of rehabilitation (ice pack, cold water immersion) can induce decreasing nerve conduction velocity. Patient who undergo cryotherapy can feel numbness and motor weakness in the affected area in a few hours [9].

In this case, the cooling pad was large compared to the patient’s body surface; in particular, the leg pad for the thigh was too long for the patient’s thigh. As a result, the cooling pad adhered over the fibular head areas where the common peroneal nerve runs. For the elderly or women, the cooling pad may be too big, which can result in unexpected complications. Patients with an underlying disease such as diabetes are also more susceptible to nerve injury [10].

0735-6757/(C) 2014

Figure. Erythematous and bullous skin lesions on the right knee.

In conclusion, although peripheral neuropathy and skin injury asso- ciated with the application of a surface cooling device for TH are rare, precautions are needed to prevent potentially devastating injuries. For prevention of cold injury-induced common peroneal palsy, proper ap- plication of the surface cooling device is important. Selection of a proper-sized cooling pad, proper application without covering the fibu- lar head area, and regular evaluation of the skin after application are crucial.

Jae Ho Jang, MD Yong Su Lim, MD, PhD? Jee Yong Jang, MD

Jae Hyug Woo, MD Won Bin Park, MD Department of Emergency Medicine, Gachon University Gil Medical Center

?Corresponding author. Department of Emergency Medicine Gachon University Gil Medical Center, 1198, Guwol-dong Namdong-gu, Incheon, 405-760, South Korea

Tel.: +82 32 460 3015; fax: +82 32 460 3019

E-mail address: [email protected] http://dx.doi.org/10.1016/j.ajem.2014.09.004

References

1. Nielsen N, Hovdenes J, Nilsson F, Rubertsson S, Stammet P, Sunde K, et al. Hypother- mia network. outcome, timing and adverse events in therapeutic hypothermia after out-of-hospital cardiac arrest. Acta Anaesthesiol Scand 2009;53(7):926-34.
2. Polderman KH, Herold I. Therapeutic hypothermia and controlled normothermia in the intensive care unit: practical considerations, side effects, and cooling methods. Crit Care Med 2009;37(3):1101-20.
3. Nielsen N, Sunde K, Hovdenes J, Riker RR, Rubertsson S, Stammet P, et al. Hypothermia Network. Adverse events and their relation to mortality in out-of-hospital cardiac ar- rest patients treated with therapeutic hypothermia. Crit Care Med 2011;39(1):57-64.
4. Jarrah S, Dziodzio J, Lord C, Fraser GL, Lucas L, Riker RR, et al. Surface cooling after cardiac arrest: effectiveness, skin safety, and adverse events in routine clinical prac- tice. Neurocrit Care 2011;14(3):382-8.
5. Liu YM, Ibrahim A, Jan T, Chang P, Fagan S, Goverman J. Skin necrosis as a complica- tion of therapeutic hypothermia. J Burn Care Res 2014;35(3):e184-6.
6. Rundgren M, Rosen I, Friberg H. Amplitude-integrated EEG (aEEG) predicts outcome after cardiac arrest and induced hypothermia. Intensive Care Med 2006;32(6):836-42.
7. Jia Jianping, Pollock Martin. The pathogenesis of non-freezing cold nerve injury. Brain 1997;120:631-46.
8. Iwin Michael S, Sanders Roy. Neuropathy in non-freezing cold injury (trench foot). J R Soc Med 1997;90:433-8.
9. Herrera E, Sandoval MC, Camargo DM, Salvini TF. Motor and sensory nerve conduc- tion are affected differently by ice pack, ice massage, and cold water immersion. Phys Ther 2010;90:581-91.
10. Kitaoka H, Majima M. Impaired regulation of skin temperature in patients with diabe- tes mellitus evaluated by the cold exposure test. Bull Osaka Med Coll 1989;35:99-105.