Unrecognized renal damage in critically ill patients.

Area of Science:

• Nephrology
• Critical Care Medicine
• Biochemistry

Background:

• Routine renal function tests like serum creatinine and urea may not detect early kidney damage in critically ill patients.
• Assessing renal function in critically ill patients requires sensitive markers beyond standard blood tests.

Purpose of the Study:

• To determine the prevalence of unrecognized renal damage in critically ill patients with normal serum creatinine, urea, and creatinine clearance.
• To evaluate the utility of various protein and enzyme excretion markers in identifying renal dysfunction.

Main Methods:

• Studied 40 critically ill male patients with high APACHE II and injury severity scores over five days.
• Measured serum creatinine, urea, creatinine clearance (24-h and Cockcroft-Gault), inulin clearance, and para-aminohippuric acid clearance.
• Assessed daily excretion of alpha-1-microglobulin, Tamm-Horsfall protein, alanine aminopeptidase, angiotensinase A, albumin, and immunoglobulin G.

Main Results:

• Nine out of 30 patients (30%) with initially normal routine renal function tests exhibited abnormal excretion patterns of proteins and enzymes.
• All ten patients with elevated routine renal parameters showed expected correlations with protein and enzyme excretion.

Conclusions:

• A significant percentage (30%) of critically ill patients with normal routine renal function indicators exhibit subclinical renal damage.
• Standard renal function tests are insufficient for detecting all forms of kidney injury in critically ill populations.
• Protein and enzyme excretion markers offer valuable supplementary information for comprehensive renal function assessment.