Normobaric Hyperoxygenation for Prevention of Contrast Induced Nephropathy

Acute renal failure induced by radiographic contrast agents is a known complication of coronary angiography.hypoxia plays a major role in the pathogenesis of Contrast induced nephropathy.

The aim of the current study is to investigate the effect of normobaric hyperoxygenation therapy on renal functions in patients at high risk for CIN undergoing coronary angiography.

The study is aimed to include 180 consecutive patients with estimated GFR base on the MDRD equation of less than 60 mL/min/1.73 m2 that are candidates for elective coronary angiography. Patients with acute renal failure, acute myocardial infarction, noncompensated congestive heart failure, hemodynamic instability, known sensitivity to contrast media and patients who had been exposed to contrast media during the last 3 months will be excluded. Patients with oxygen blood saturation of less than 94% at room air will also be excluded from the study.

Study protocol Patients will be randomly assigned to receive either 100% oxygen by mask (treated group) or breath room air (control group) for duration of 4 hours starting at the beginning of the angiographic procedure.

All patients will be treated with 0.9% salin and NAC. Coronary angiography will be performed using nonionic, low osmolar iodine (Ultravist®-370) (Schering, Berlin, Germany).

All patients will be hospitalized 1 day before and at least 24 hours following angiography. Blood samples for urea, creatinine and cystatin- C will be drawn on admission, 6, 24 and 48 hours after coronary angiography. Urine sample will be taken 24 hours before angiography and 6, 24 and 48 hours post angiography. In those urine samples the ratio between creatinine to Isoprostanes and NO will be evaluated.