Renal function impairment (RFI) in the ICU: a 1-year prospective study

We studied prospectively the characteristics and the outcome of patients with RFI in the ICU. RFI was defined as a serum creatinine concentration (sCr) remaining ≥ 1.6 mg/dl, for at least two consecutive days during hospitalization in the ICU (sCr normal value ≤ 1.5 mg/dl). From 1 October 2000 until 30 September 2001, among 362 adult patients (247 M, 115 F, aged 52.4 ± 19 years) who were admitted and remained into the ICU for at least 2 days (mean 13.2 ± 17.3 range 2–143), 60 patients, 16.5%, (42 M, 18 F, aged 58.5 ± 18.1 years) fulfilled the criteria for RFI. They were divided into two groups, A and B according to the timing of RFI development. Group A included 27 patients (19 M, 8 F, aged 60.5 ± 15.4 years) who developed RFI after their admission into the ICU. APACHE II score, BUN and sCr at admission were 18.5 ± 5.8, 23.3 ± 17.9 mg/dl and 1.2 ± 0.2 mg/dl respectively. The mean time to fulfill the criteria of RFI in these patients was 8.4 ± 6.2 days. Group B included 33 patients (23 M, 10 F, aged 56.8 ± 20.1 years, P = NS comparing to group A), who were admitted into the ICU with a sCr ≥ 1.6 mg/dl, which remained there at least for 2 days. APACHE II score, BUN and sCr at admission were 25.1 ± 7.4, 66.4 ± 43.7 mg/dl and 3.6 ± 2.9 mg/dl respectively (P < 0.001 for each parameter, comparing to group A). The mean time of ICU hospitalization was 21.5 ± 26.2 days in patients of group A and 25 ± 30.9 days in patients of group B (P = NS). Oliguria during ICU hospitalization (defined as 24 hour urine output < 450 ml/day) was observed in seven patients (25.9%) of group A and in 15 patients (45.4%) of group B (P = NS). Seven patients of group A and 13 patients of group B were treated finally with CVVH (P = NS). Among the 60 patients with the RFI 44 died (23/27 in group A and 21/33 in group B, P = 0.055). Among the rest 302 patients, without RFI, 76 patients died (P < 0.0001 comparing to the patients with RFI).

We conclude that in ICU patients a sCr which remains ≥ 1.6 mg/dl, for at least two consecutive days, constitute a bad prognostic factor.