Systemic Sclerosis for Lithotripsy

You are in the preadmission anaesthesia clinic. A 57 year old male presents to the clinic prior to extracorporeal shockwave lithotripsy for a staghorn calculus. His past medical history includes systemic sclerosis. Medications listed are: Prednisone 2.5 mg daily Mycophenolate 3g daily Insulin Humalog 16 units three times daily and Lantus 25 units at night Apixaban 5mg twice daily Irbesartan 300mg daily Vitamin D 1000 IU daily Magnesium 500mg twice daily Artificial tears prn Investigations included: Pulmonary function tests CXR Full blood picture Urea and electrolytes 6 minute walk test