Page 379 - Critical Care Nursing Demystified

364 CRITICAL CARE NURSING DeMYSTIFIED

calcium are linked together; deficiency in one has a significant effect on the
other as magnesium helps the absorption of calcium in the intestines. In de-
creased kidney function, greater amounts of magnesium are retained and
therefore an increased blood level occurs. Normal value is 1.3 to 2.1 mEq/L.
Serum sodium – Most abundant cation in extracellular fluid. Usually where
sodium goes, water goes. Influenced by ADH and aldosterone. Normal value
is 135 to 145 mEq/L

Uric acid – In renal failure this rises as the kidney’s are unable to excrete this
by-product of purine metabolism. Normal value is 2.5 to 7.0 umol/L.

Urine osmolality – Tests concentration of solutes in the urine. Ability to
concentrate urine is lost in renal failure. Normal value is 1.010 to 1.025.
Urine protein – The kidneys do not excrete protein as it is a large molecule
and does not pass through the nephron. In renal diseases, proteinuria will
result. Normal urine contains no protein.
Urinary RBCs – Since RBCs are large molecules, they do not normally pass
into the urine. Presence is indicative of UTI, renal obstruction, inflammation,
or trauma. Normal urine contains no RBCs.
Urinary WBC – Urinary infection and inflammation will result in an increase Downloaded by [ Faculty of Nursing, Chiangmai University 5.62.158.117] at [07/18/16]. Copyright © McGraw-Hill Global Education Holdings, LLC. Not to be redistributed or modified in any way without permission.
in WBC growth in the urine. Normal urine contains no more than four
WBCs per high-powered field.

NURSING ALERT

Obtain a urine specimen prior to administering a diuretic. This will more accurately
reflect the patient’s urinary status.

Diagnostic Studies

ECG/EKG (electrocardiogram) – Shows the response of the heart to electrolyte
imbalance by changes in waveforms and presence of rhythm disturbances.
KUB (kidney ureter bladder x-ray) – Shows position of kidney and presence
of renal calculi or tumors. No contrast medium is used.

Renal biopsy – A small sample of the kidney is removed percutaneously to
test for cellular type (tumor), damage (pyelonephritis), or rejection (renal
transplantation). The nurse needs to perform frequent vital signs and moni-
tor the site for bleeding and infection.
Renal angiography – Involves injection of contrast medium into the renal arterial
tree to visualize kidney structures through fluoroscopy. Shows the presence of
abnormal blood flow, renal artery stenosis, cysts or tumors, renal trauma, and