Background: Patients often receive IV sedation and nasal cannula O2 during monitored anaesthesia care (MAC). Over-sedation/airway obstruction may cause severe desaturation, especially in obese patients with obstructive sleep apnoea (OSA). A novel nasal TSE-PAP mask assembly using a paediatric mask and existing anesthesia equipment/machine was shown to maintain spontaneous respiration and improve oxygenation in sedated obese patients with OSA(1-3). We report its use in an obese OSA patient with difficult airway during oesophagogastroduodenoscopy (OGD). 

Case Report: A 68 y/o obese male (BMI 41 kg/m2) with known difficult airway, OSA, asthma, tracheal stenosis, HTN, hepatitis C, NIDDM, oesophageal varices presented for OGD. 

He reportedly required tracheostomy after hernia repair 14 yrs ago and forgot to bring his surgeon's note stating that he needed endotracheal intubation anytime he received anesthesia. He also had a history of post-extubation stridor after GA. He had a Class III airway, large tongue, short neck with a large tracheostomy scar, mild expiratory wheezes and room air SpO2 of 93%. 

After discussing with him and the endoscopist, the procedure was to proceed under MAC with video-laryngoscopy standby. He gave consent for photography and case report. 

After he was pretreated with lignocaine and albuterol nebulizer, an infant mask with fully inflated air cushion was placed over his nose and secured with a hook ring and rubber head straps and connected to a breathing circuit and the anaesthesia machine (Fig. 1-3). The APL valve was adjusted to deliver 8 cm H2O CPAP with 4 L/min O2. His SpO2 increased to 97%. He maintained spontaneous ventilation and 98-100% SpO2 throughout (Fig. 2-3).

He tolerated the procedure well without any complication. He was elated that intubation was avoided. He was discharged home without any problem. 

Discussion: This simple nasal TSE-PAP assembly maintained spontaneous ventilation and improved oxygenation in an obese patient with a known difficult airway, OSA and tracheal stenosis under sedation. It utilizes existing anaesthesia equipment and machine and may improve patient safety at a low cost. 

References: 1. www.TSEMask.com; 2. SAMBA 28th AM, 2013; 3. IARS AM: MCC1080, 2015Learning Points: How to prepare a nasal mask

A novel nasal PAP mask assembly maintained spontaneous ventilation and improved oxygenation in an obese patient with OSA, difficult airway, asthma and tracheal stenosis under MAC during ambulatory OGD