A Randomised, Single-Blind, Controlled Trial of Silicone Disposable Laryngeal Masks During Anaesthesia in Spontaneously Breathing Adult Patients (Report‪)‬

The classic Laryngeal Mask Airway (cLMA) (LMA-Classic[TM], The Laryngeal Mask Company Limited, Henley-on-Thames, UK) is a reusable supraglottic airway device developed by Dr Archie Brain during the years 1981 to 1988 (1). Reusable laryngeal mask airways (LMA) require a process of washing and preparation for repeat use: however, it has been shown that even repeat autoclaving does not remove protein deposits, thus potentially allowing disease transmission through residual biological debris (2). The increased awareness of possible cross infection associated with reusable airway devices has increased the use of single-use disposable LMAs manufactured from polyvinyl chloride (PVC). PVC contains chemicals called phthalates, such as di-2-ethylhexyl phthalate, which are used to increase the plastic's flexibility. These chemicals however are not linked to the plastic matrix and may slowly leach out during use (3). Phthalates are potentially "carcinogenic, mutagenic and reprotoxic" (3). In response to concerns with PVC LMAs, a number of disposable silicone LMAs have been manufactured, such as the Meditech Systems Limited (MSL) and ProAct (PA) LMAs. We evaluated the use of the PA and MSL (disposable silicone) LMAs in adult patients undergoing general anaesthesia who were breathing spontaneously. The primary outcome variable was airway sealing pressure.