Oxygen desaturation following sedation for regional analgesia.

Moderate to severe arterial oxygen desaturation (SaO2 75-88%) occurred in three of four patients who were given sedation during regional conduction block without the administration of oxygen. No desaturation occurred in six patients given oxygen 2 litre min-1 via a nasal catheter during similar procedures. It is concluded that patients undergoing regional conduction block with concurrent sedation should receive additional oxygen routinely unless a pulse oximeter is available for monitoring.