When a Patient with CKD Needs Contrast Radiography

Case A 70-year-old woman is hospitalized after a fall that resulted in a right femoral neck fracture. Her medical history includes obesity, type 2 diabetes mellitus, hypertension, and chronic kidney disease (CKD). She has smoked a pack of cigarettes daily for 40 years. Results of the patient's initial workup in the emergency department demonstrated the right femoral neck fracture, serum creatinine of 1.8 mg/dL, and a negative noncontrast head CT. She was admitted to the hospital and the following day underwent surgical repair. The procedure was uncomplicated. However, on postoperative day 4 the patient is developed sudden onset chest pain and shortness of breath. The acute coronary syndrome work-up is negative. Current medications include prophylactic subcutaneous heparin, insulin glargine, omeprazole, and paracetamol. Temperature is 37.8 degrees C, blood pressure is 110/65 mm Hg, pulse is 116/min, and respirations are 30/min. Pulse oximetry is 88% on room air. Lung auscultation revealed decreased breath sounds at the bilateral bases. Cardiac rhythm is regular with normal S1 and S2. The surgical incision shows no surrounding erythema or purulent drainage. The patient follows commands and moves all extremities except the left leg. Laboratory results are as follows: Complete blood count: Leukocytes 12,000/mm(3), Hemoglobin 11 g/dL, Platelets 250,000/mm(3), Serum biochemical tests: Sodium 135 mEq/L, pH: 7.48, pCO2: 30, mmHg, pO2: 85 mmHg, Bicarbonate 24 mEq/L, serum creatinine: 1.8 mg/dL, Glucose 170 mg/dL, Troponin T is undetectable. Chest x-ray shows slight bibasilar atelectasis without focal consolidation, pleural effusion, or pulmonary edema. ECG shows sinus tachycardia but is otherwise unremarkable. Which of the following is the most appropriate next step in management of this patient? a) IV antibiotics b) IV furosemide c) IV nitroglycerine infusion d) Ventilation perfusion scan e) Computed tomography (CT) pulmonary angiography