Horner’s syndrome following internal jugular vein cannulation

We present two cases of Horner's syndrome occurring following uncomplicated internal jugular venous cannulation. An awareness of this potential complication will reduce confusion over the aetiology of anisocoria in critically ill patients. This consideration is important, since lesions in the central nervous system or carotid dissection following trauma might otherwise be suspected. Received: 25 July 1997 Accepted: 28 November 1997