Safety with anaesthesia--the paradigm of continuous improvement.

Since the advent of general anaesthesia over 150 years ago it has been recognised that the price of human safety while unconscious is eternal vigilance by the caregiver, the ability to handle life threatening problems and a systematic analysis of error. John Snow, a pioneer of anaesthesia and clinical epidemiology, placed reliance on observation of the respiratory pattern and the pulse and such clinical monitoring was the mainstay of safe anaesthetic practice for over a century. I