Formalin (0.25%) as topical anti-microbial agent in burns.
In a prospective controlled trial, 0.25% formalin spray was compared with 2% silver sulfadiazine cream as the local treatment of burns. Formation and separation of eschar, infection and death rates were recorded. In the group receiving formalin, rates of formation and separation of eschar were significantly more (P less than 0.001 and P less than 0.05 resp.) compared to other group. Infection rate and fatality due to infection were also reduced. Other advantages of formalin are ease of application and the low east.
Many effective antibacterial substances are now available for topical application in the prophylaxis of sepsis in burns. However, they have a few practical disadvantages viz., necessity of bulky cotton dressings (silver nitrate) or messy painful application if the agent is cream based (silver sulfadiazine, mafenide acetate and providone iodine). In addition, complications such as metabolic acidosis disturbances of thyroid function  and tissue deposition of silver have been reported after their use.
In search of effective local antimicrobial agent, it appeared that 0.25% formaldehyde solution (formalin) in a form of a spray would be more convenient. Formalin releasing solutions such as noxythiolin and taurolin have been reported to be used for peritonitis,. They possess bactericidal, sporicidal and virucidal properties. Formalin has been used to prevent Haemorrhage from bladder tumours and in urine bags to reduce the incidence of urinary tract infection. It has been tried in the conservative management of carbuncle and therapy of leg ulcers secondary to peripheral vascular diseases. The present controlled prospective study was designed to evaluate efficacy of 0.25% formalin spray as an antiseptic in the management of burns and to compare it with the routinely used agent silver sulfadiazine.
Forty cases admitted to a single surgical unit between March 1986 and January 1989 were included in this study. They were divided into 2 groups viz. study group and control group.
Study group comprised of 20 patients (age ranged between 13 and 45 years; mean 28.86 yrs) with extent of burn injury varying from 10% to 74% (mean 35.07%) of body surface area. Nine patients had superficial and 11 had deep burns. They were treated with 0.25% formalin (3 nil of 40% formalin to 497 ml of normal saline) sprayed with an ordinary spray (sterilised) over the burns till an eschar was formed. After the eschar formation the wound was dressed with Eusol. The patients were given sedation (1 ml of pentazocine) for the first three days to relieve pain just prior to spray. No occlusive dressings were used, and the patients were nursed on ISOMED sterishects. A steel cradle was used to prevent bed sheets from coming in contact with the burn wounds. The average cost of application per patient was around Rs. 20.
The control group had 20 patients (age range: 16-56 yrs; mean 25.86) with extent of burns varying from 10 to 50% (mean 27.36%) of body surface area. Superficial burns were found in 11 patients and deep in remaining 9 patients. Two per cent silver sulfadiazine was applied topically to their burns. Occlusive gauze dressings were then applied which were changed daily. The average cost of therapy per patient was approx. Rs. 200.
In addition to intensive monitoring, intravenous fluids were administered to all the patients according to Parkland's formula . Baseline investigations included estimation of Haemoglobin, packed cell volume, total and differential blood count, urea nitrogen, liver function tests. Burn wound biopsies were evaluated for culture on admission, and were repeated every week. Cultures were considered significant if the growth exceeded 10 organisms per gram of burn tissue. Renal chcmistry and liver function tests were monitored weekly. Prophylactic antibiotics were administered in the form of Ampicillin and chloramphenicol for 10 days and modified according to the sensitivity report. The patients were managed as inpatients until the healing process was complete. Superficial burns healed without any further treatment and deep burns, required skin grafting after healthy granulations had appeared.
Time taken for eschar formation and separation, development of infection, mortality if any and duration of hospital stay were noted for each patient and both the groups were compared statistically using 't' test with respect to these parameters.
Eschar formation occurred after 3.45 ? 0.52 days in the study group. Eschars were found to be dry without any exudation or maceration of wound and surrounding edema was less as compared to that observed in the control group. In the latter group, eschar formation was observed after a longer period (6.00 ? 1.22 days) than in study group (P < 0.001). Eschar separation in the study group commenced after 13.73 ? 3.29 days as compared to 18.67 ? 6.34 days in the control group (P < 0.05)
Only 3 patients in study group developed wound infection. Klebisella were isolated from wound swabs in 2 patients and E. coli in case of remaining one. On the other hand, 9 of 20 silver sulphadiazine treated cases got infected; 7 with klebisella, 1 with pseudo-monas and 1 with E. coli.
The mortality due to septicacmia was 1 in the study group as against 7 from the control group. The overall mortality was of 5 patients in the study group and of 8 in the control group; the causes apart from septicacmia were toxacmia of burns (3 patients in the study group and 1 from the control group died of toxacmia) and bronchopneumonia (1 patient from the study group). Those who died of toxacmia showed reduced urinary output from the 3rd or 4th day of burns and none showed any evidence of wound infection.
The average duration of hospital stay was 26.3 ? 17.9 days in the study group and 22.86 ? 14.17 days in the control group when all the patients were considered. If only survivors are taken into consideration, average hospital stay for study group was found to be 31.9 ? 15.9 days and for control group, 29.2 ? 13.33 days. No local or systcmic toxic reactions were observed following formalin spray. The only complaint was of stinging sensation when formalin was sprayed on the raw wound, how-ever it lasted only for short time (average 3 days).
Spraying of 0.25% formalin as an antiseptic for burns appeared to be more convenient and time-saving than application of cream. Need for occlusive dressing did not arise with spray, permitting better physiotherapy. As patients complained of stinging pain on spraying, an analgesic was used prior to spray to decrease the intensity of pain.
Formation and separation of eschar occurred earlier in the formalin treated group. This may be attributable to the absence of wound exudation or maceration following spraying of formalin. Such factors allow faster 1. healing of superficial burns or early granulation of deep burns. However, in the present study, no significant difference was noted in the hospital stay of both the groups. 2. This may be due to the difference in the extent of burns in two groups (in the study group, 12 patients had more than 30% burns and in control group only 7)
Incidence of infection was significantly lesser in the study group; so was the mortality due to septicaemia. Thus formalin was found to be effective even in presence of hospital strains.
With 0.25% formalin we did not find any local or systemic toxicity. Reports have however appeared describing the occurrence of malignancy in certain groups of individuals. Carcinogenic risk of formalin vapours has been reported in mice. But undue importance should not be given to these findings in the light of the report by Jenson, who studied the cancer registry in Denmark and found that between 1943 and 1976 only 3 cases of nasal carcinoma had been reported in doctors, none of whom were pathologists or anatomists (the two branches of medicine most exposed to formalin inhalation.) This risk gets much more reduced by limiting exposure of formalin to a very short time in patients with burns.
Thus we conclude from this study that formalin as an antiseptic not only improves the outcome of burns (by decreasing infection) but itís also, easy, safe and economical.
We thank Dean, Seth GS Medical College and King Edward Memorial Hospital for permitting us to utilise hospital records and publish this data and constant encouragement.