Comparison of efficacy and cost-effectiveness of 0.55% ortho-phthalaldehyde and 2% glutaraldehyde for disinfection of laryngoscopes: A prospective pilot study

BACKGROUND AND AIMS The laryngoscope is a potential source of cross-infection as it involves contact with the mucous membrane, saliva and occasionally blood. This study compared efficacy and cost-effectiveness of two Centre for Disease Control approved agents for disinfection of laryngoscope blades. METHODS One hundred and sixty patients requiring laryngoscopy and intubation for general anaesthesia were randomly allocated into two groups. After tracheal intubation, used laryngoscope blades were cleaned with tap water. The blades were then immersed in either 2% w/v glutaraldehyde for a contact time of 20 min or 0.55% w/v ortho-phthalaldehyde (OPA) for 10 min. The handles were wiped with 0.5% w/v chlorhexidine wipes. Samples were collected using sterile cotton swabs from the tip, flange and light bulb area of the laryngoscope blade and one from the handle. They were cultured aerobically on blood and McConkey agar. RESULTS In 2% glutaraldehyde group, of 240 samples sent from the blades, 2 (0.8%) showed the growth of methicillin-resistant coagulase-negative staphylococci (MRCONS) and Enterobacter. In OPA group, of 240 samples, 2 (0.8%) showed growth of MRCONS. Thus, 2% glutaraldehyde and 0.55% OPA were comparable in terms of efficacy of disinfection. Growth was seen on 4 out of 160 handles. CONCLUSIONS We suggest OPA for high-level disinfection of laryngoscope blades as it is equally efficacious as compared to glutaraldehyde, with a shorter contact time and available as a ready to use formulation.