THAT’S why you feel so groggy after an op

elDerly patients and the very young are particularly vulnerable to confusion and grogginess long after coming round from a general anaesthetic.

now scientists think they know why.

Propofol, a commonly used anaesthetic, is known to act in much the same way as a sleeping pill, but a team at the University of Queensland in australia has found it also stops brain cells communicating with one other, by blocking a protein, syntaxin1a, that helps form connections between these cells.

These connections may be weaker in the young and old, say the researchers in the journal Cell reports. The findings could lead to new forms of anaesthesia.