Try and attend to nurse patient’s last sign of life (9)
I believe the answer is:
heartbeat
'sign of life' is the definition.
'try and attend to nurse patient's last' is the wordplay.
'try' becomes 'hear' (as in to try someone in court or hear their case).
'and' means one lot of letters go next to another.
'attend' becomes 'be at' (to be at an event is to attend it).
'to nurse' is an insertion indicator.
'last' suggests the final letters.
The last letter of 'patient' is 't'.
'hear'+'beat'='hearbeat'
'hearbeat' placed around 't' is 'HEARTBEAT'.
(Other definitions for heartbeat that I've seen before include "Circulation noise" , "Animating force" , "Essential pulsation" , "Pulse of cardiac origin" .)