Electrolyte abnormalities before and after the onset of acute renal failure

The chemical composition of body fluids, which is regulated by the kidneys, may affect renal function. Conversely, the onset of acute renal failure (ARF) interrupts the normal regulation of the volume and content of the body fluids. In order to further study these relationships and determine the epidemiology and consequences of ARF in a tertiary-care setting, the computerized hospital data base was used to identify and obtain laboratory data on patients with ARF. 9,276 patients, encountered over a 90-day period, were surveyed and 96 were found to have developed ARF in the hospital (3.1% of admissions). The majority of the patients with ARF were found on the medicine service (68%), and sepsis with aminoglycoside use was the single most common of multiple etiologic factors. Patients with ARF experienced an increase in morbidity, as evidenced by an increase in the hospital length of stay and frequent need for ICU care. Mortality (29%) was due to the patients' underlying illnesses, and not uremia. Serum levels of the electrolytes prior to the onset of ARF were within the normal range with the exception of the creatinine (2.04 +/- 0.25 mg/dl) and bicarbonate (22.9 +/- 0.6 meq/l). After the development of ARF (mean creatinine 3.91 +/- 0.03) sodium, chloride, and bicarbonate were decreased, and phosphate, uric acid, and the anion gap were increased (p less than 0.05 for all values). The decrease in serum calcium became significant (p less than 0.05) in those patients whose creatinine increased by a factor of 2 or more.