Strike by hospital employees at first that covers a wide area (6)
I believe the answer is:
swathe
'that covers a wide area' is the definition.
'strike by hospital employees at first' is the wordplay.
'strike' becomes 'swat' (**).
'by' says to put letters next to each other.
'at first' suggests taking the first letters.
The initial letters of 'hospital employees' is 'he'.
'swat'+'he'='SWATHE'
(Other definitions for swathe that I've seen before include "Bandage completely - band of mown grass" , "Wrap in bandages - broad mown band" , "A broad strip as of cut grass" , "Strip cut by a scythe" , "Broad strip or area; wrap in fabric" .)