Sleep, interrupted

An obese patient presents with a long history of snoring and choking arousals

Peter is a 65-year-old man who is having an endoscopic retrograde cholangiopancreatography (ERCP) for endoscopic resection of an ampullary adenocarcinoma.

He is under sedation in the swimmers position — lying prone with his head tilted sideways. During the ERCP, Peter has an apnoeic episode. He desaturates to 70% and becomes cyanotic.

He is tachycardic (132/min) and his BP is 146/92mmHg. Chest examination is unremarkable. The procedure is abandoned, Peter is repositioned and oxygen administered. His oxygen saturation improves.

Full blood count, urea,