Clinical Efficacy Evaluation of Supraglottic Airway Device SafeLM™ in Paediatric Population

Paediatric patients who are scheduled for surgery where supraglottic airway is deemed appropriate will be recruited with written consent. Following preoxygenation, application of standard monitors, and induction of general anaesthesia, an appropriate size of SafeLM™ will be inserted according to manufacturer's recommendation. Cuff will be deflated and flattened prior, with the back of laryngeal mask lubricated. The device will be advanced by sliding the laryngeal mask down the palatopharyngeal curve along the midline in the mouth until the end of the mask reach the hypopharynx cavity and resistance is met, with the process visualised in real time through the video camera. If there is malalignment, correction manoeuvre such as jaw trust, head reposition, or mask redirection will be done. Once the distal end of mask reaches the hypopharyngeal cavity, the cuff is inflated with the recommended volume of air according to the manufacturer recommendation, until adequate cuff seal is achieved. Then, the patient is put on either spontaneous or pressure-controlled mechanical ventilation. Successful placement will be confirmed. If insertion difficulty is encountered and the laryngeal mask is required to be taken out from the oral cavity, insertion can be reattempt with the same or different size of SafeLM™ after adequate preoxygenation, and it will be considered as second attempt. If it remains unsuccessful on the 3rd attempt, SafeLM™ insertion will be abandoned, subsequent management will be decided by the attending anaesthetist. Glottic exposure grades at the end of each attempt is recorded. The time for insertion is measured for each attempt, using a stopwatch, by obtaining the duration in between the moment when the anaesthetist starts holding the SafeLM™ device, until the appearance of 2 complete continuous capnography waveform on the monitor. Following successful SafeLM™ insertion, the camera can be removed, and orogastric tube will be inserted via the gastric port only if there is clinical indication. Subsequently, oropharyngeal leak pressure (OPLP) is measured and recorded by dialing the fresh gas flow rate to 3 L/min and putting the adjusting pressure limiting (APL) valve at 40 cmH2O, in manual ventilation mode. The equilibrium pressure that the pressure gauze pointer settles down at is the OPLP. The anaesthesia is maintained using TIVA or volatile agent as per the anaesthetist's discretion, keeping the MAC at least 1.0 or BIS level at 40-60, whichever is applicable. All the patients will receive IV dexamethasone 0.2 mg/kg and IV granisetron 0.02 mg/kg as post operative nausea vomiting (PONV) prophylaxis. At the end of anaesthesia, anaesthetic agent administration is terminated. If non-depolarising neuromuscular blockade is given during anaesthesia, an appropriate dose of reversal agent will be given according to the depth of neuromuscular blockade based on either clinical signs or nerve stimulation examination, whichever applicable. After the adequate neuromuscular blockade reversal is confirmed, the laryngeal mask can be removed at the awake state or deep plane of anaesthesia. Patient will be monitored in the post-anaesthesia care unit for at least 30 minutes prior sending back to the designated ward for continuation of care.