Hi Sudipta,
I hope you have checked the logs generated by the patch update for any possible issues.
Make sure oracle_home is same for sidadm orasid and listener.ora
Give a full restart of you server and start oracle with orasid. Now give R3trans -d.
Check alert logs
Also, have a look at 491174 - Composite SAP note for ORA-01034
If this is not working then we can move further.
Regards