E Coetzee1, A Whitelaw, D Kahn, H Rode. 1. Department of Surgery and Microbiology, University of Cape Town, South Africa. edt.coetzee@gmail.com
Abstract
BACKGROUND: Burn wound infections are a major cause of morbidity and mortality. The bactericidal action of sodium hypochlorite has been known for centuries and it has been in clinical practice for over 70 years. Whereas a buffered sodium hypochlorite solution is not universally available, an un-buffered solution is cheap and easy to prepare. AIM: The aim of this study was to determine the optimum concentration with regard to safety and efficacy, as well as shelf life of an un-buffered sodium hypochlorite solution for the topical management of burn wound infections. METHODS: Human fibroblasts were exposed to serial dilutions of un-buffered sodium hypochlorite solutions for 30 min and assessed for viability. Isolates of Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pyogenes were exposed to the same dilutions of un-buffered sodium hypochlorite to establish the minimum bactericidal concentration. The pH, osmolality and electrolyte concentrations were measured. These experiments were repeated with solution stored at room temperature for 6 consecutive days. RESULTS: 24% of fibroblasts were viable after exposure to a 0.025% solution and 98.9% with a 0.003% solution. The MBC for the P. aeruginosa isolates was 0.003%, for S. aureus was 0.006% and for S. pyogenes was 0.0015%. This remained constant for 6 consecutive days. The un-buffered 0.0025% solution has a pH of 10, an osmolality of 168 sodium concentration of 89 mmol/dl and chloride of 84 mmol/dl. This remained stable for 14 days. CONCLUSIONS: An un-buffered solution of sodium hypochlorite with a concentration of 0.006% would be suitable for the topical management of burn wound infections caused by common pathogens. It has a shelf life of at least 6 days.
BACKGROUND: Burn wound infections are a major cause of morbidity and mortality. The bactericidal action of sodium hypochlorite has been known for centuries and it has been in clinical practice for over 70 years. Whereas a buffered sodium hypochlorite solution is not universally available, an un-buffered solution is cheap and easy to prepare. AIM: The aim of this study was to determine the optimum concentration with regard to safety and efficacy, as well as shelf life of an un-buffered sodium hypochlorite solution for the topical management of burn wound infections. METHODS:Human fibroblasts were exposed to serial dilutions of un-buffered sodium hypochlorite solutions for 30 min and assessed for viability. Isolates of Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pyogenes were exposed to the same dilutions of un-buffered sodium hypochlorite to establish the minimum bactericidal concentration. The pH, osmolality and electrolyte concentrations were measured. These experiments were repeated with solution stored at room temperature for 6 consecutive days. RESULTS: 24% of fibroblasts were viable after exposure to a 0.025% solution and 98.9% with a 0.003% solution. The MBC for the P. aeruginosa isolates was 0.003%, for S. aureus was 0.006% and for S. pyogenes was 0.0015%. This remained constant for 6 consecutive days. The un-buffered 0.0025% solution has a pH of 10, an osmolality of 168 sodium concentration of 89 mmol/dl and chloride of 84 mmol/dl. This remained stable for 14 days. CONCLUSIONS: An un-buffered solution of sodium hypochlorite with a concentration of 0.006% would be suitable for the topical management of burn wound infections caused by common pathogens. It has a shelf life of at least 6 days.