The effect of steam sterilisation at 134 °C on light intensity provided by fibrelight Macintosh laryngoscopes

Abstract

SummaryWe studied the repeated effect of sterilisation on light intensity in laryngoscopes from Penlon, Riester, Heine (two different blades), Medicon and Upsher. Light intensity was measured by a light meter using two methods. Measurements were performed before the decontamination procedure was carried out and subsequently after each series of 25 procedures until a total of 200 cycles was reached. Using method 1 (and 2), the reduction in light intensity after 200 cycles was 100% (100%; no light emitted), 37% (13%), 75% (69%), 79% (60%), 37% (14%) and 63% (55%) for each blade, respectively. Keywords Equipment; laryngoscopes. Infection control; sterilisation. disinfection. Larynx; laryngoscopy. To prevent infection, decontamination of laryngoscopes is of vital importance, especially in the immunocompromised patient. Although decontamination should start with rigorous mechanical cleaning [1], machine washing being the most effective method, controversy exists as to whether this should be followed by highlevel disinfection or sterilisation [1±3]. Recently, this discussion became particularly relevant when Control of Substances Hazardous to Health (COSHH) regulations applicable throughout the EC made many disinfection agents (e.g. glutaraldehyde solutions) no longer easily accessible. In this respect it is disturbing that alcohol, a frequently used alternative, is not considered to be a high-level disinfectant [1]. There is a high incidence of noncompliance with current guidelines [4,5] and the result of any decontamination protocol relies on consistent adherence [3,6]. These problems can be overcome with the use of sterilisation.However, one of the potential disadvantages of steam sterilisation at 134 8C is that it might be detrimental to ®brelight blades. We are unaware of data describing the effect of steam sterilisation on the ®brelight laryngoscope blades currently on the market. We therefore undertook this study to evaluate the effect of automated machine washing and subsequent steam sterilisation at 134 8C on various ®brelight laryngoscope blades and handles, focusing on the effect on light intensity provided by the blades. Methods

The effect of mechanical cleaning and thermal disinfection on light intensity provided by fibrelight Macintosh laryngoscopes

“…In a previous study it was shown that there were substantial differences between fibrelight laryngoscope blades' ability to withstand the detrimental effects of steam sterilisation at 134°C [7]. In addition, even the best performing blades showed considerable reductions in light intensity after only 200 cycles [7]. However, this study had several limitations such as the small number of participating manufacturers, testing of only one blade of each type, and steam sterilisation of all blades at 134°C.…”

“…Recently, Control of Substances Hazardous to Health (COSHH) regulations applicable throughout the European Union have rendered many high-level disinfectants no longer easily accessible. This has resulted in an increased need to rely on thermal disinfection and ⁄ or sterilisation procedures, which are known to be detrimental to fibrelight bundles [7]. In a previous study it was shown that there were substantial differences between fibrelight laryngoscope blades' ability to withstand the detrimental effects of steam sterilisation at 134°C [7].…”

“…This has resulted in an increased need to rely on thermal disinfection and ⁄ or sterilisation procedures, which are known to be detrimental to fibrelight bundles [7]. In a previous study it was shown that there were substantial differences between fibrelight laryngoscope blades' ability to withstand the detrimental effects of steam sterilisation at 134°C [7]. In addition, even the best performing blades showed considerable reductions in light intensity after only 200 cycles [7].…”

The effect of single use laryngoscopy equipment on illumination for tracheal intubation*

“…We would advise others to carefully assess the options in their hospital, such as using condoms to cover the blade [12], disposable blades or even changing to sterilizing used laryngoscopes. It is interesting to note that even changing the method of cleaning laryngoscopes may change their performance [8].…”

“…We measured illumination by a method similar to that previously described [8] (Fig. 1), lining the blade up with a mark on the inside wall.…”