Da Silva J.C., Bento C., Coelho M.J., Almeida M.A.

Plastic, Reconstructive and Aesthetic Department and Burn Unit, São José Hospital, Lisbon, Portugal

SUMMARY. A study was made of thirty patients who sustained chemical burns between May 1998 and May 1999. The criteria considered were sex, age, origin of accident, chemical agent, immediate washing with water, localization, extent and depth of burn, need for hospitalization, and average healing time. Young males suffering work-related accidents were the most frequent victims. Acid was the most frequent agent involved and the hands were the most frequent site of injury. Most burns were small and of second degree, did not require hospitalisation, and healed within two weeks. In certain cases wound healing was delayed for unknown reasons, requiring repeated surgical interventions. Chemical burns accounted for 1.9% of all admissions to the Burns Unit of the São José Hospital.

Introduction

Chemical products are fundamental in our modern society. They are used in numerous industrial and domestic activities and may also be agents of aggression. Approximately 6,000,000 chemical substances known to man, of which 95,000 are marketed and used as medicines, fertilizers, pesticides, cleaning products, disinfectants, paint and other coating removers, solvents, cements, and for other purposes.

Chemical products may be divided into acids, bases, organic compounds, and inorganic compounds. As reported in the literature, sulphuric acid and caustic soda are the acid and base respectively responsible for most burns. Acids and bases have different mechanisms of injury. Acids, like thermal burns, cause coagulation necrosis via intracellular dehydration and protein coagulation, thereby limiting the spread of the chemical in the tissues. Bases destroy cells, forming soaps with fat and hydrolyse proteins causing a liquefactive necrosis that facilitates the spread of the chemical agent.

Cells may be damaged by reduction, oxidation, corrosion, protoplasmic poisoning, desiccation, and vesication. Tissue damage depends on the concentration and quantity of the chemical, the surface area of contact and its duration, the reactivity of the agent, and the amount of heat released by the exothermic reaction.

First aid after a chemical burn should aim to remove the victim from the danger area and remove all clothing impregnated with the chemical, without causing injury to the rescuer. Washing with copious quantities of water should be carried out on site for 15 to 30 minutes. This should be done within the first hour of injury and then repeated in the emergency room for a period of 2 h in the case of acids and 12 h in the case of bases. Although some antidotes exist, the use of water is preferable because the exothermic reaction resulting from the combination of strong acids and bases may cause further thermal injury. The exceptions are burns caused by hydrofluoric acid and oxalic acid, in which case calcium gluconate should be used.

A careful history and physical examination are required. The extent and depth of the burns must be established, and ocular, inhalation, and aspiration burns must be sought. Additionally, associated physical injuries must be looked for. The shock-prevention and resuscitative measures are similar to those used in thermal burns. Early debridement of blisters is important to eliminate the chemical substance rapidly. The biochemical monitoring of these patients is important, since once in the systemic circulation some chemicals may cause cardiac, pulmonary, renal, or hepatic damage. Hydrofluoric acid, for example, causes hypocalcaemia, which may lead to abnormalities of cardiac conduction and even ventricular fibrillation.

The decision to hospitalize a patient may be difficult when the patient is first seen soon after the accident. The extent of the injuries is frequently not immediately evident, and in doubtful cases it is best to admit the patient to hospital and monitor him closely.

Materials and methods

The study was conducted between May 1998 and May 1999, coinciding with the opening of the Out-patient Burns Clinic at the São José Hospital in Portugal in May 1998. All 30 chemical burns cases seen at the Hospital were included in the study.

The parameters considered were gender, age, origin of accident, the chemical agent, immediate washing with water, localization, extent and depth of burn, the need for hospitalization, and the average healing time.

Results

• The average age of the patients was 43 years.
• Most patients were male (Fig. 1).

• Most accidents were work-related (Fig. 2).

• The commonest agents were hydrofluoric acid and caustic soda (Fig. 3).

• The commonest site of injury was the upper limb, especially the hand.
• Ten patients were washed with water immediately after the accident.
• Chemical burns were mostly smaller than 1% (Fig. 4) and second degree (Fig. 5).

• Most patients did not require hospitalization (Fig. 6). Of the 13 admitted two required care in the Burns Unit, while the rest were treated in the Plastic Surgery Ward (Fig. 7).

• Six patients required surgery, of whom three required multiple interventions.
• The average time for wound healing was two weeks (Fig. 8). However, two patients with wound relapse needing repeated surgery took six months to heal.

Discussion

In our study, young males suffering work-related accidents were the most frequent victims of chemical burns. Acids were the most frequent causative agents. However, there were also burns caused by agents of unidentified composition.

The most frequently burned areas were the hands, followed by the lower limbs and trunk.

Most burns were minor and of second degree.

The patients needing admission were burned by ammonia, caustic soda, hydrofluoric acid, iodine, and unidentified industrial chemicals. Two victims of industrial chemicals required multiple surgery and presented delayed wound healing for up to 6 months.

The 1.9% prevalence of chemical burns out of all burns patients admitted to our Burns Unit is in keeping with the figures reported in the literature ranging from 1.4 to 4%.

RESUME. Les Auteurs ont étudié trente patients atteints de brûlures chimiques pendant la période mai 1998-mai 1999. Les critères pris en considération étaient le sexe, l’âge, la cause de l’accident, l’agent chimique, le lavage immédiat avec de l’eau, la localisation, l’extension et la profondité de la brûlure, la nécessité de l’hospitalisation, et le temps moyen de guérison. Les patients mâles atteints de brûlures dues à des accidents liés au travail étaient les victimes les plus communes. L’acide était l’agent intéressé le plus fréquemment et les mains étaient le site le plus commun. La plupart des brûlures étaient petites et de deuxième degré, ne nécessitaient pas l’hospitalisation et guérissaient en moins de deux semaines. Dans certains cas la guérison des lésions était retardée pour des raisons inconnues, ce qui nécessitait des interventions chirurgicales. Les brûlures chimiques constituaient 1,9% de toutes les hospitalisations dans l’Unité des Brûlures de l’Hôpital São José.

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