Kidney Function and Waste Products

• Acute Kidney Injury (AKI) typically occurs between T12 and L3 in the retroperitoneal area.
• Renal colic, or kidney pain, can radiate down to the toes.
• Right kidney sits slightly lower than the left due to the liver.

Kidney Function

• Excretes waste products, purifying blood by removing substances like phosphates, urea, and creatinine.
• Regulates blood pressure via the renin hormone.
• Impaired kidney function can lead to fluid overload, causing shortness of breath.
• Chronic kidney disease may lead to dialysis and loss of hemoglobin.
• Kidneys not producing erythropoietin can be linked to renin-angiotensin blockers (ARBs).

Waste Products

• Blood urea and creatinine levels reflect waste product buildup.
• Creatinine indicates protein breakdown.
• Blood urea indicates muscle breakdown.

Blood Filtration

• Kidneys filter approximately 1.50 liters of blood in 24 hours.
• Nephrons filter the blood with the urine traveling from the renal pelvis to the bladder via the ureters.
• Bladder capacity is about 750ml.
• The center of the pons in the brain controls the urination.
• Urination involves both voluntary and involuntary muscle control.

Acute Kidney Injury

• AKI results in waste accumulation due to dehydration or vomiting.
• Elevated BUN and creatinine levels along with low urine output are key indicators.

Types of AKI

• Prerenal AKI is caused by severe dehydration, heart failure, or low cardiac output, leading to low blood pressure.
• Intrarenal AKI is caused by nephrotoxic medications like "-mycin" antibiotics, metformin, or IV contrast dyes.
• Accumulation of blood waste in the glomeruli increases BUN and creatinine, resulting in azotemia and potentially oliguria.
• Post-renal AKI is associated with obstructions.

AKI vs. Chronic Kidney Disease

• AKI is potentially reversible with proper management.
• Chronic kidney disease is irreversible.

Kidney Function

• Kidneys excrete unwanted potassium and renin, while reabsorbing bicarbonate to buffer acid.
• Hypovolemia can lead to AKI.
• Antibiotics require renal lab monitoring due to kidney filtration.

Phases of Kidney Injury/Recovery

• Initial kidney injury affects function because of blood loss.
• The diuretic phase signifies recovery.

Clinical Manifestations of AKI

• Oliguric Phase: Urine output less than 400ml/24 hours, dark urine possibly containing casts, RBCs, and WBCs, lasting 10-14 days.
• Fluid overload signs include edema, heart failure, crackles in lungs, labored breathing, low oxygen saturation, hypertension, and low heart rate.
• Fluid retention can lead to pulmonary edema.
• Metabolic acidosis may cause Kussmaul respirations.
• Hyponatremia can lead to cerebral changes and altered consciousness.
• Hyperkalemia is often asymptomatic.
• Leukocytosis and elevated BUN and creatinine levels.
• Neurological disorders: fatigue, difficulty concentrating, seizures, stupor, or coma may occur.

AKI Nursing Considerations

• Monitor strict intake and output is important along with monitoring lungs, respiration, edema, and weight.
• Diuretic Phase: Monitor for hyponatremia, hypokalemia, and dehydration as nephrons recover; daily output may reach 1-3 liters.
• Treatment for blood loss involves IV fluids.
• Vancomycin levels should be monitored due to kidney impact.

AKI Labs

• Sodium - monitor levels
• Potassium - monitor levels
• Blood Urea - monitor levels
• Creatinine - monitor levels

AKI Diagnosis

• Ultrasounds are used to check for kidney stones.
• Biopsies determine the degree of kidney damage.
• CT scans without IV contrast are preferred in the ER for those with Chronic kidney disease.
• Metformin and long-term "-mycin" antibiotics are not good for kidneys. Use of contrast studies can damage the kidneys.

AKI Management

• Manage the patient with attention to medications history and general studies.
• Massive blood loss causing acute kidney injury requires fluid replacement.
• Oliguria requires careful management via diuretics.

AKI Treatments

• Loop diuretics or mannitol may be administered.
• Avoid administration of potassium.
• Administer 10 units of IV insulin and dextrose to shift potassium into cells.
• Administer sodium bicarbonate for metabolic acidosis.
• Administer Calcium carbonate to manage.
• Sodium Kayexalate is administered to remove potassium, causing diarrhea.
• Avoid Kayexalate if bowel sounds are absent to prevent bowel necrosis.

Failed AKI Treatments

• Immediate temporary dialysis is required if patient does not respond to treatments and suffers from pulmonary edema.
• Emergency dialysis catheter placement may be needed if renal function is fully compromised.
• Continuous Renal Replacement Therapy (CRRT) may be needed if the patient is hypotensive instead of dialysis.

AKI Nutrition

• Nutrition therapy includes restricted sodium and potassium intake, with protein intake not being restricted.

AKI Monitoring

• Vital signs and fluid intake and output should be monitored.
• Signs of fluid overload along with level of consciousness should be monitored.
• Heart rhythm, daily weight, and electrolyte levels should be monitored.
• Significant fluid losses should be replaced.
• Aggressive diuretic therapy should be provided for fluid overload.
• Nephrotoxic substances should be avoided.

Explore kidney anatomy, location, and critical functions like waste excretion and blood pressure regulation. Learn about the implications of impaired kidney function, including fluid overload and the potential need for dialysis. Understand how blood urea and creatinine levels indicate waste product buildup, and the kidneys' efficiency in filtering blood.