Freon is a chemical halogenated chlorofluorocarbon (CFC) used frequently as an industrial refrigerant. It is a clear, colorless gas or liquid normally found in refrigerators, air conditioners, freezers, dry-cleaning solvents, blowing agents, chemical excipients topical anesthetics, water coolers and aerosols.^1,2 These refrigerant liquids and compressed gases may cause frostbite when contacted on the skin.² Though some cases of Freon inhalation injury are described in the literature, regardless of its extensive use only a few reported cases of Freon frostbite have ever been published.^2,3 One published case happened in a tropical state which was our southern neighbor country and to the best of the authors’ knowledge here we reported the first such cases in Malaysia, a tropical country.

Case report

Case 1

A 22-year-old air-conditioner male technician presented to our burn center with a history of compressor gas contact while at work more than 24 hours previously. The alleged gas r22 was jetted to his right hand for a brief 10 seconds as he tried to conceal it from further leakage and had immediately caused cold, pain and subsequently felt the burn. He then ran his hand through running cold tap water for a few minutes and left it exposed until the next morning when he reported to our burn center as the condition did not improve; he had developed multiple blisters, had a swollen hand and numbness over the right hand.

Upon examination, he was noted to have sustained mixed dermal partial thickness burns over the right hand. There were multiple burn wounds most of which were deep dermal partial thickness burns at the dorsum aspect of 2^nd, 3^rd, 4^th and 5^th digits and superficial dermal partial thickness at the volar aspect of 2^nd and 3^rddigits whereby the middle finger wound was circumferential in nature (Figure 1).

Figure 1. Right hand in dorsum and volar view shows multiple mixed thickness burn wounds with deep dermal partial-thickness wounds mostly at the dorsum aspect which had been de-roofed and superficial dermal partial -thickness at the volar aspect of the hand

The wound was initially dressed conservatively and a tangential excision following thick split-thickness skin grafting was done subsequently on the 3^rdday of admission after the wound had fully demarcated (Figure 2).

Figure 2. Right hand in dorsum and volar view with thick split thickness skin graft applied to the wounds

The skin graft was taken well and successive follow up 6 months later clinically showed some hyperpigmented scar, no more numbness with a good range of movement of 80 degrees’ flexion at DIP and 100 degrees’ flexion at PIP in all affected fingers and no contracture had occurred (Figure 3). No blood investigation or imaging was repeated.

Figure 3. Right hand in dorsum and volar view shows 6 months post operation with well-healed skin graft with no contracture

Case 2

A 25-year-old male engineer was checking on an air-conditioner system in a server room when a sudden leak of Freon gas sprayed on his gloved hands for about 5 seconds. He immediately took off his gloves and put his hands under running tap water for about 5 minutes. He then sought treatment at a general outpatient clinic and the wound was dressed with normal saline on daily basis. On day-4 post-injury, persistent pain and swelling prompted him to seek medical attention at the casualty where he was subsequently referred to our burn center unit. On examination, there was gross soft tissue swelling of the right hand (Figure 4) with a large blister on the center of the palm, filled with gel-like material. Similar blisters were also found on the first web space and base of the left thumb. Otherwise, circulation was good with normal distal skin perfusion with CRT less than 2 seconds. Apart from extreme tenderness, there were no signs of cellulitis or ongoing infection. Additionally, he was afebrile and hemodynamically stable. Full blood count and renal profile findings were unremarkable.

Figure 4. Gross swelling of the right hand with blisters on the palm in volar view

Under intravenous analgesia, bedside wound debridement was done whereby all loose, devitalized tissue was removed, revealing a blanchable, superficial dermal partial thickness type of burn wound (Figure 5).

Figure 5. After removing blisters and loose tissues

For the next eleven days, he was observed closely and treated with modern dressing using ionic silver integrated hydrofiber dressing. He was discharged with a completely healed burn (Figure 6) and normal hand functions 14 days later; he had no contracture and good range of movement of 100 degrees’ flexion at PIP and 90 degrees’ flexion at MCP in all affected fingers.

Figure 6. Right hand in volar view and left hand in dorsum view which shows completely healed burn at two weeks

Freon-induced cryoinjuries are rare. Reported cases are typically work-related as the majority of individuals do not have access to Freon.¹Skin interaction with Freon can make the skin dry, leading to contact dermatitis, mild discomfort or rash. Freon may also cause severe frostbite.²Frostbite is injury produced by the freezing of the tissue, frequently the hands and feet in about 90% of reported injuries, owing to contact to extreme cold. Frostbite can also affect the face, buttocks or perineum and penis.^4,5

Most frostbite casualties that take place in urban areas are homeless or have mental health issues or cognitive alteration. These casualties are more likely to be males, presenting frostbite on the limbs, and in the 30 to 49 years age group. Currently, the appearance of frostbite is growing although limited within the public residents, in particular, those who participate in winter games such as skiing, hiking and ice climbing or include those injured in vehicular mishaps.^4,5 However, frostbite due to Freon is much rarer that can occur in any part of the world including tropical or hot climate countries due to its industrial related injury.

Frostbite harms the flesh in 2 ways, through direct cellular injury and through progressive dermal ischemia. The former begins with the development of extracellular ice crystals, process which is followed by alterations in cells osmotic gradient. This therefore leads to intracellular dehydration and ice formation, amplified intracellular concentration of electrolytes, and mechanical obliteration of cells.⁵ The latter is more detrimental that it is comparable to the occasions that lead to reperfusion injury in which inflammatory substances, causing edema, endothelial damage, and stopped dermal perfusion. Defrosting causes early vasoconstriction of microvessels briefly, followed by recommencement of capillary perfusion which is then interrupted by cascades of emboli in microvessels. These cause additional tissue injury from severe thrombosis and hypoxia.⁵ Freon has an intense cooling consequence, causing cryoinjury through localized cellular damage when being contact with the skin for more than 3 seconds. The injury may be more severe compared to a thermal burn owing to its lipid solubility which rapidly and deeply penetrates the skin, potentially causing irreversible damages. Additionally, it may result in a compartment syndrome.^1,2

Clinically, it is challenging to firstly evaluate the extent of frostbite injury. There could be a varied inconsistency amongst the degrees of injury against the deeper components. Over the past 10 years, the management of frostbite has significantly improved with the advent of clear guidelines and protocols which are now accessible.¹ Principles of management encompass quick rewarming to defrost ice and stop direct cellular injury, post rewarming care and proper wound care including debridement to stimulate well-timed recovery. Field rewarming should only be attempted if there is no additional risk of refreezing, which would otherwise result in more severe injury.^4,5 Nonetheless in our reported cases, rewarming could be done on-site as the culprit was not owing to the extremely cold environment but due to the Freon gas. The Wilderness Medical Society and State of Alaska Cold Injury Guidelines endorse a temperature of 37-39°C, which reduces the ache whilst only slightly reducing the rewarming period with the ideal time period varying from 15 minutes to 1 hour.⁴

Heparinization to avoid thrombosis is still debatable. Active movement during rewarming is beneficial, however, massage should be avoided.²Conversely, use of tissue plasminogen activator (rTPA) and heparin post rapid rewarming is safe and found to reduce digit amputations.⁴Fasciotomy, debridement, and hyperbaric therapy were stated formerly as possibly valuable treatments. However, early debridement can lead to loss of reversibly damaged tissue, causing unwarranted scarring and unfavorable long-term function. Likewise, an excessively conservative method may end in deteriorating infection with progressive tissue necrosis.¹ Thus, allowing demarcation of nonviable tissues is recommended and surgery should be deferred until the area is properly demarcated.²

With the various approaches of treatment available in literature over the years, most cases of Freon induced burn shared a similar presentation with our cases; second-degree frostbite had conducted a range of therapy from conservative, modern dressing to excision and skin grafting. In separate papers, Ogawa and Celalettin reported the wounds healed gradually within 2-3 weeks by conservative treatment only while Sever required the wounds to heal over 8 weeks with excisional debridement and regular dressing. Kua in Singapore reported the use of negative pressure wound therapy and hyperbaric oxygen therapy (HBOT) combination for their cases which presented with compartment syndrome.¹ A conservative approach and the use of HBOT alone resulted in the wound to heal in two weeks.² Nonetheless, sympathectomy and hyperbaric therapy both have conflicting experimental data and no demonstrated clinical significance.⁵ There were two cases which involved progression to 3^rd degree injury whereby one was treated with excision following skin graft and the other with flap reconstruction.¹ However, there was one case reported with loss of tissue, which required skin grafting and amputation of multiple digits. In our case, the Freon caused transient and rapid tissue damage to deep dermal partial thickness and eventually had fully demarcated earlier on course, therefore we are assured that the patient may benefit from early surgical intervention for quick recovery, shorter hospital stay, and prevention of severe long term sequelae.

Freon burn is a serious ailment which can be linked with substantial morbidity. Appropriate pre-hospital intervention and definitive treatment are imperative to decrease tissue damage and optimize the outcome of the injured extremity. Early surgical means can be attempted for better outcome provided the wound has fully demarcated and no additional complication is expected and conservative treatment by means of dressing can be employed on superficial thickness burn injury.

1. Kua EHJ, Tanri NP, Tan BK, Ng SW. Cryoinjury with compartment syndrome of bilateral hands secondary to Freon gas: a case report and review of current literature. Eur J Plast Surg 2015;38:77-80. [Crossref]

2. Özkaya Ö, Egemen O, Bingöl D, Akan IM. Unusual both hands cryogenic burn caused by Freon gas and early treatment with hyperbaric oxygen therapy. Inj Extra 2011;42:192-4. [Crossref]

3. Wisler JW, Wisler JR, Coffey R, Miller SF. The diversity of wound presentation associated with Freon contact frostbite injury. J Burn Care Res 2010;31:809-12. [Crossref]

4. Handford C, Buxton P, Russell K, et al. Frostbite: A practical approach to hospital management. Extrem Physiol Med 2014;3:7. [Crossref]

5. Hutchison RL. Frostbite of the hand. J Hand Surg Am 2014;39:1863-8. [Crossref]