Analysis of two groups of patients with acute renal failure in the critical care setting

Introduction

Acute renal (ARF) failure has a notable prevalence in the ICU. When patients are identified by small alterations in the creatinine levels, the percentage of ARF may reach 25% in the critically ill.

Objective

To evaluate ARF in two groups of patients: Group A (GA), patients with ARF at admission to the ICU; Group B (GB), patients developing ARF during the ICU stay.

Materials and methods

A prospective survey, carried out between July 2004 and February 2005 in a tertiary care private hospital. The sample was composed of two groups. GA: patients with ARF at admission, creatinine >2.0 mg/dl and normal renal function prior to the admission. GB: patients with normal renal function, with a 0.5 mg/dl increase in the serum creatinine during the ICU stay or if presented with chronic renal failure, defined as serum creatinine >2 and <4.9 mg/dl, an increase of 1.0 mg/dl in serum creatinine levels. Patients with serum creatinine level >5 mg/dl, history of ARF in another hospital or kidney transplant were excluded.

Results

Six hundred and eighty patients were admitted to the ICU during the study period. Sixty-five patients had ARF, 14 in GA and 51 in GB. The mean age was 62.79 years and 69.4 years, respectively. The causes of ARF in GA were hypoperfusion (28.6%) and sepsis (21.4%), whereas in GB they were hypoperfusion (35.3%), septic shock (29.4%) and sepsis (19.6%). The prevalence of contrast-induced ARF was 7.1% in GA, and 2.0% in GB (P < 0.05). The mean serum creatinine level was 4.2 mg/dl in GA and 2.7 mg/dl in GB (P < 0.05). The mean urine output measured 24 hours before the diagnosis of ARF was 551.08 ml in GA and 713.37 ml in GB. The APACHE II score was 33.94 in GA and 41.76 in GB. The mortality in GA was 28.6% (four patients) and was 58.8% in group B (30 patients) (P < 0.05). The mortality for the ICU in general was 13.2% (90 patients). Twenty-three patients went for dialysis: GA 35.7% (five patients) and GB 35.29% (18 patients). The mean number of sessions was 4.78 in GA and 3.2 in GB. Four patients in GA (80%) and 15 (83.3%) in GB died in the dialysis group.

Conclusions

The ARF mortality remains high despite the advances in technology, notably in patients on dialysis. In some cases the ARF diagnosis was delayed, as demonstrated by the serum creatinine levels in GA.