A patient 38 yrs old male K/C/O HTN, CKD-V on MHD, Chief C/O breathlessnes , high grade fever, decreased appetite , cough. CXR-PA view showes B/L diffuse infiltrates Rt Lt, mostly upper lobe. PCT 10, TLC within normal range. ABG Respiratory acidosis . Patient is on IV antibiotics Colistin 1 million IU TDS, Inj. Meropenem 1Gm TDS, Inj. Sulbactam 500 mg IV TDS, Patient is reponding much with antibiotic therapy . plz guide for further plan of investigation and treatment.