Professor Khan is confident that the new technique will be particularly useful for patients who are at risk under a general anaesthesia.

BBC: heart op

In an interview with the BBC, Professor Khan credited the success of the operation to his anaesthetist, Dr Mubashir Zia, who he said had made the operation possible by rendering the spine numb using an epidural, rather than by general anaesthesia.

BBC: heart op

Warren Zapol, of the Massachusetts General Hospital and a professor of anaesthesia at Harvard Medical School, along with his colleagues, monitored the vital signs of mice exposed to low-dosages (80 parts per million) of hydrogen sulphide for several hours.

ECONOMIST: Researchers find hydrogen sulphide can lower metabolism