Unexpected intraoperative hypoxaemia in a healthy dog undergoing TPLO

A period of hypoxaemia was unexpectedly detected in an otherwise healthy 10‐year‐old dog undergoing tibial plateau levelling osteotomy surgery. Hypoxaemia developed approximately 10 minutes after the start of surgery. Simultaneously, the plane of anaesthesia was persistently light. Lung compliance was subjectively poor. Among other treatment attempts, an alveolar recruitment manoeuvre was performed, which resolved the hypoxaemia, probably caused by atelectasis. Once normoxaemic, bradycardia ensued but resolved after administration of atropine. A variety of factors may have promoted the presentation in this dog, including prolonged recumbency and a leak around the endotracheal tube. The dog recovered without complications.