Microwave Treatment of Cold Injuries

Abstract

In spite of the fact that extremity frostbites are a widespread type of injuries in many countries, specialized equipment for frostbite treatment is lacking. Treatment is carried out by conservative methods. The best results are obtained by using thermal isolation of injured tissues and activation of internal warming. It is proposed to initiate deep warming of frostbitten extremities on exposure to low-power microwave radiation. A microwave chamber has been developed to implement this technique. The efficiency of the approach was earlier demonstrated on animals. An example is given of successful treatment of a cold injury of patient hands and feet that allowed amputation to be avoided.

INTRODUCTION

One of the pathologies common for many countries with cold climate is a cold injury. Cold traumas are also quite often encountered in warm countries in highlands, stations, and mounting skiing resorts. For example, a large number of frostbites permanently occur in the Indian States Jammu and Kashmir. The duration of and expenses on the frostbite treatment exceed those on the burn treatment. The most part of cold injuries ends with amputations and disabilities.[1,2,3,4]

However, there is still no certified hardware for treating such injuries.

This article describes the application of two approaches to treating frostbite. The first is based on medication aimed at enhancing blood flow. The second, fundamentally new in the practice of treating human cold injury, is based on the use of deeply penetrating low power microwave radiation for restore of blood flow in deep-seated vessels and muscle mass.[5,6]

This method has been successfully tested on animals.[7]

CASE REPORT

Patient C, 27-year-old, Medical History No. 21-18047, was hospitalized on December 29, 2018 and was discharged from the hospital on February 1, 2019 (34 days in bad) with the diagnosis: general hypothermia, stuporous stage, the 2°–4° frostbite of hands and feet, early reactive period, and the 2° frozen lumbar region. He lay on the street at a temperature of–27°C for about 5 h.

His toes and fingers were cyanotic, had ligneous density, were insensitive, movements were very difficult, hemorrhagic blisters and subungual hematoma were observed (heavy-degree frostbite), and the Billroths test was negative. A pronounced swelling of feet was observed above the ankle joints and of hands above the wrist joints. The surface temperature of feet and hands was +12°C. It is well known that the blood flow stops at a tissue temperature of from +15°C to +19°C, the critical temperature for fingers is +19°C, and for the foot +15°C.[4,5] At temperatures below critical, recovery of limbs by medication does not give positive results.

Accordingly, for this patient, the expected outcome is amputation of the extremities: legs-at the level of the ankle joints, and hands-at the level of the wrist joints.

An accelerated admission of the patient to a hospital was used with the treatment of the skin of the affected segments with an aseptic solution and the imposition of heat-insulating covers (the thickness of the cotton-gauze bandage was 5 cm). For the treatment of this patient, a device based on a closed microwave chamber[8] and a microwave low-power generator of electromagnetic radiation with a frequency of 2.45 GHz was used.

A device for treating frostbite of the extremities by the method of microwave rewarming is shown in Figure 1.

Figure 1.

External view of the microwave chamber for frostbite rewarming (at the left) and of the impulse centimeter-wave-therapy CMWi-200-Med TeCo device (at the right) used as a source of microwave radiation

The setup contains a source of microwave radiation representing a device for impulse centimeter-wave-therapy CMWi-200,[9] (manufacturer-“Med TeCo” plant, Mytishchy, Moscow region, RF) and a shielded working chamber connected to it with a coaxial cable supplied with the CMWi-200 device. A microwave power radiator (antenna) is placed in the chamber. The use of the modern and mass-market CMWi-200 device as a microwave radiation source ensures the 2.45 GHz frequency stability and possibility of choosing the microwave radiation power within therapeutically necessary limits. The working chamber is a closed metal volume with dimensions of 30 cm × 40 cm × 50 cm with a hole 24 cm in diameter for placing a warmed limb in the chamber. The hole is equipped with a soft radioprotective sleeve, which has an inner layer of a metallized polymer film that protects the patient and staff from unwanted microwave radiation.

When working with the device, the object of influence (frostbitten limb) is placed into the cavity of the working chamber through a protective sleeve. When the microwave source is turned on, the microwave energy through the coaxial cable enters the cavity of the working chamber. Since the walls of the chamber and the metallized film of the sleeve effectively reflect the microwave radiation, all the power supplied to the chamber is dissipated within the treated object, warming it both on the surface and in depth. This achieves the desired therapeutic effect, which consists in relieving the spasm of the main deeply located feeding vessels and restore blood flow.

The surface temperature (the skin temperature) of the warmed-up limb was monitored using an electrothermometer TPEM-1,[10] (Medical equipment plant NPO “Medfizpribor,” Kazan, RF), and the state of blood supply of damaged segments is measured with a portable rheovasograph Mitsar– REO,[11] (“MITSAR-EEG“-plant, St-Petersburg, RF) using computer program for registration and analysis WinReo.

In parallel, a course of conservative vascular, antibacterial, infusion therapy was carried out. Intravenous solutions of drugs warmed up to 40°C were injected in a volume of up to 800–1000 ml to avoid an increase in edema and secondary microcirculation disorders:

• 200.0 ml of 5% glucose solution

  1. 2.0 units of insulin solution
  2. 100.0 ml of 0.25% Novocain solution

• 200.0 ml of 0.9% sodium chloride solution

  1. 20.0 ml of 4% calcium chloride solution
  2. 5 thousand units heparin solution

• 400.0 ml of reopolyglukin solution

  1. 5.0 ml of 1% nicotinic acid solution
  2. 2.0 ml of No Spa solution.

Five thousand units of heparin were injected after 4 h subcutaneously in the umbilical region of the abdomen under the control of the coagulation system of blood.

Dermal blisters appeared in the reactive period were opened, their fillings are removed, and the area was covered with a sterile bandage.

On the day of admission December 29, 2018 [Figure 2a and b] and on the next day, December 30, 2018 the hands with the forearms and the feet with the lower third of the legs [Figure 2a and b] were heated in a microwave chamber for 30 min at a power of 30W for hands and of 45 W for feet. Temperature on the toes before rewarming +12° C, the lower third of the legs +15° C, after rewarming they increased to +34° C.

Figure 2.

Feet (a) and hands (b) in the 1^st day of hospitalization

Already at the end of the day December 29, 2018, after microwave exposure, active movements and sensitivity on the feet and hands were restored. At December 30, 2018 after microwave exposure, sensitivity on the fingers was restored, edema decreased markedly [Figure 3].

Figure 3.

Feet after microwave exposure in the chamber

During the treatment, the positive dynamics was observed, including normalization of the temperature and skin color and restoration of functions of both hands and feet. However, dry gangrene of nail phalanxes of the 1–4 toes of both feet started in the 2^nd week on the treatment [Figure 4].

Figure 4.

Intermediate stage – epidermal peeling off and pulling away of the finger skin (a) and mummification of the nail phalanxes of toe (b)

On January 24, 2019, the nail phalanges of the 1–4 toes of both feet were amputated under spinal anesthesia [Figure 5a]. The postoperative period was uneventful with healing by primary tension. Peeling and discharge of surface necrosis of dermis on hand fingers were observed with preservation of deep layers of dermis. The supportability of the lower extremities, the function of the hand fingers, and the hand skin were saved [Figure 5b].

Figure 5.

Intermediate stage – after surgery (a) and outcome (b) after removal of sutures and healing of wounds by primary tension

The patient was discharged from the hospital in a satisfactory state February 1, 2019.

DISCUSSION

Monitoring the patient's condition over the next year and a half did not reveal any consequences of microwave exposure applied during the treatment of cold injury. It is essential that the use of only the indicated medication methods of treatment would not allow this patient to save his hands and fingers, feet. A randomized study of the efficacy of drug-only treatment for deep frostbite[12] showed some advantage of iloprost and iloprost plus recombinant tissue plasminogen activator, but there was still an insufficient base of existing evidence for these methods of preventing amputation. In our opinion, in case of deep frostbite, there will always be problems with the movement of drugs through cooled vessels, and the use of heating with deeply penetrating fields should help to solve these problems.

CONCLUSIONS

For a patient with deep frostbite of the extremities, hospitalized in the early reactive period, the use of a microwave device containing a closed microwave chamber and a low-power microwave generator significantly improved treatment results, avoided necrosis and extensive amputation.

Although promising results have been obtained for this patient, they should of course be confirmed in other patients with sufficient statistics.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient has given his consent for his/her/their images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

Research quality and ethics statement

The authors followed applicable EQUATOR Network (http://wwww.equator-network.org/) guidelines, notably the CARE guideline, during the conduct of this report.

Financial support and sponsorship

This work was supported in part by the Tomsk State University Academic D.I. Mendeleev Fund Program.

Conflicts of interest

There are no conflicts of interest.