Sinus arrest during thoracic drain placement in a dog

A 5‐year‐old female neutered Podenco Canario dog presented with a moderate pleural effusion and subsequently underwent placement of bilateral thoracic drains. Pre‐medication consisted of intravenous medetomidine (2 µg/kg) and methadone (0.2 mg/kg), followed by induction with propofol (2.1 mg/kg, via intravenous administration). Anaesthesia was maintained with isoflurane in 100% oxygen. The modified Seldinger technique was used to place bilateral small‐bore, wire‐guided thoracic drains. During placement of the first chest drain, the dog developed sinus arrest. It is suspected that there was direct vagal nerve stimulation by the guide wire during placement, leading to severe bradycardia and subsequent sinus arrest that was responsive to atropine. It is important to note that the definitive cause of the transient cardiac arrest could not be ascertained. It is possible that this is a rare complication of thoracic drain placement, warranting further research in this area.