Elimination

What is elimination and which organs are involved?

• Excretion of waste products from the body

• Organs involved:

  • Kidneys

  • Skin

  • Lungs

  • Intestines

What are the main functions of the kidneys?

• Regulate fluid volume

• Regulate electrolytes

• Maintain acid-base balance

• Excrete metabolic waste (BUN, creatinine)

• Produce hormones (erythropoietin, renin)

• Bone mineralization (activate vitamin D)

• Form urine (filtration, reabsorption, secretion)

What happens when kidney function fails related to fluid, electrolytes, and acid-base balance?

• Fluid overload → edema, pulmonary edema, HTN

• Electrolyte imbalances (especially ↑K⁺)

• Metabolic acidosis

What lab changes occur when kidneys cannot excrete metabolic waste?

• ↑ BUN

• ↑ Creatinine

Why do patients with kidney failure develop anemia?

↓ erythropoietin → ↓ RBC production → anemia → fatigue

How does kidney failure affect calcium levels?

↓ activation of vitamin D → ↓ calcium absorption → hypocalcemia

What urinary changes occur with kidney dysfunction?

• Oliguria (↓ urine)

• Anuria (no urine)

• Proteinuria

• Hematuria

• Glucosuria

What is the role of renin in kidney function?

• Part of RAAS system

• Converts angiotensin I → angiotensin II

• Causes vasoconstriction

• ↑ BP

• Promotes Na⁺ and water retention → ↑ blood volume

What are the priority assessment areas for kidney dysfunction using ABCDE?

• A: usually unaffected

• B: pulmonary edema, crackles, hypoxia

• C: dysrhythmias (electrolyte imbalance), HTN

• D: confusion (uremia)

• E: edema, dry/uremic skin

What are signs of fluid volume overload in renal patients?

• Edema

• Weight gain

• Crackles

• Elevated BP

What electrolyte imbalances are seen in kidney dysfunction?

• Hyperkalemia ⭐

• Hypocalcemia

• Hyperphosphatemia

• Hypermagnesemia

What abnormal urinary patterns should the nurse recognize?

• Oliguria

• Anuria

• Pyuria

• Bacteriuria

• Proteinuria

• Hematuria

• Dysuria

What is a key red flag symptom for kidney problems?

Flank pain ⭐

What medical history increases risk for renal problems?

• Hypertension

• Diabetes

• Lupus (SLE)

• Infections (especially strep)

What is the BEST indicator of kidney function?

GFR (glomerular filtration rate) ⭐

What happens to GFR in renal failure?

GFR decreases because the kidneys lose their ability to filter blood effectively due to nephron damage → less blood is filtered → ↓ GFR

What happens to creatinine in kidney dysfunction?

Creatinine increases because it is a waste product normally excreted by the kidneys → when filtration decreases, creatinine builds up in the blood

What happens to BUN in renal impairment?

BUN increases because urea (a nitrogen waste product) is not being excreted → accumulates in the bloodstream

What happens to hemoglobin, hematocrit, and RBCs in renal failure?

They decrease because the kidneys produce erythropoietin (EPO) → in renal failure, ↓ EPO → ↓ RBC production in bone marrow → anemia

What happens to serum albumin in kidney disease?

Albumin decreases because damaged glomeruli allow protein to leak into urine (proteinuria) → loss of albumin from the blood → ↓ serum albumin → leads to edema

What acid-base imbalance is seen in kidney failure?

Metabolic acidosis

What complications can occur with chronic kidney disease?

• Pruritus (uremia)

• Dysrhythmias

• Heart failure (S3)

• Anemia

• Bleeding

• Pulmonary edema

• Infection

• Bone disease (renal osteodystrophy)

Why are renal patients at risk for bone disease?

• ↑ phosphate binds calcium

• PTH pulls calcium from bones → weak bones

What are the most important things to monitor in renal patients?

• Urine output ⭐

• BUN & creatinine

• Potassium (risk for dysrhythmias)

• Fluid status (weights, edema)

• Mental status (uremia)