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

Abstract

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.

Contamination and Disinfection of Rigid Laryngoscopes: A Literature Review

“…Most of the studies (n = 4) were published in 2017, with one study each published in 2013, 2016, and 2018 . One study was conducted in the United States and two in India . One study each was conducted in Brazil, Iran, Korea, and the United Kingdom .…”

“…The researchers concluded that 2% glutaraldehyde and 0.55% OPA are equally effective for processing laryngoscope blades; however, processing with 0.55% OPA requires a shorter processing time. Because there was microbial growth on 2.5% of the laryngoscope handles after disinfection with 0.5% chlorhexidine germicidal wipes, the researchers also concluded the wipes were not effective for disinfection of laryngoscope handles …”

“…When comparing germicidal wipes used for LLD of laryngoscope handles, Howell et al found there was a residual disinfectant effect when using CHG wipes, but also recommended intermittent steam sterilization of laryngoscope handles disinfected with CHG wipes. Karnik et al found bacterial growth on 2.5% of laryngoscope handles after LLD with germicidal wipes, which supports the need for improved processing methods. For this reason, perioperative leaders and other health care team members using or processing rigid laryngoscopes should consider both the laryngoscope blade and handle to be semicritical items that need to be processed in accordance with the manufacturer's IFU with either HLD or sterilization.…”

“…When the laryngoscope blade is inserted into the patient's mouth and larynx, it can damage the oral mucosa and lead to transmission of microorganisms from the contaminated blade into the patient's mouth and lungs . The health care provider handling the laryngoscope also is at risk for contact with and transmission of pathogenic microorganisms from the contaminated laryngoscope blade and handle …”

“…The blade is therefore a semicritical item that should be processed by sterilization or, at a minimum, by HLD . Microorganisms can be pathogenic on laryngoscope blades even when using US Food and Drug Administration–cleared high‐level disinfectants …”