Low incidence of nephropathy in surgical ICU patients receiving intravenous contrast: a retrospective analysis

Objective: Various studies have documented a markedly high incidence of contrast-induced nephropathy (CIN). Most of these studies were conducted in patients not in the ICU. In ICU patients intravenous contrast may be withheld for fear of CIN. We investigated the incidence of CIN in ICU patients. Design and setting: Retrospective cohort study in a 12-bed tertiary surgical ICU. Patients: Were evaluated all contrast-enhanced abdominal computed tomography (CT) scans between 1995 and 2003 in patients not on renal replacement therapy (RRT) before the CT. Patients received prophylactic prehydration and, since 2000, acetylcysteine. Low-osmolarity, nonionic contrast was used. CIN was defined as an increase in serum creatinine of more than 44 mu mol/l (0.5 mg/dl) within 48 h after contrast administration, with no increase in creatinine of 44 mu mol/l during the preceding 2 days. RRT initiated after the CT was also recorded. Measurements and results: The patient was not on RRT before CT in 486 of 589 cases (16% diabetics). In these 486 cases the median (IQR) creatinine decreased significantly from 88 mu mol/l (66-124) on the day of the CT-scan to 84 mu mol/l (63-118) 2 days later. Only 7 of the 486 cases (1.4%) fulfilled the criteria of CIN, and in another 17 (3.5%) RRT was started after the CT. Important coexisting causes of renal failure were present in these patients, and in all survivors renal function recovered. Conclusions: CT with modern contrast is associated with a very low incidence of nephropathy in predominantly nondiabetic surgical ICU patients. Intravenous contrast should only rarely be withheld in these patients.