11 Mar Renal Assessment (Exam 3) Flashcards
What is the primary function of the kidneys?
Regulates EC volume, osmolarity, composition, and BP; excretes toxins; maintains acid/base balance; produces hormones.
What is the normal range for serum creatinine?
0.6-1.3 mg/dL.
What is the glomerular filtration rate (GFR)?
125-140 mL/min.
What is the hallmark of acute kidney injury (AKI)?
Azotemia: buildup of nitrogenous products such as urea and creatinine.
What are common symptoms of hypernatremia?
Orthostasis
Restlessness
Lethargy
Tremor/Muscle twitching/spasticity
Seizures
Death
What is the treatment for hypokalemia?
Treat underlying cause; potassium PO > IV; generally K+ given at 10-20 mEq/L/hr IV.
What is the normal range for ionized calcium (iCa++)?
1.2-1.38 mmol/L.
What is the most common form of AKI?
Pre-renal azotemia.
What is the BUN:Creatinine ratio in pre-renal azotemia?
> 20:1.
Fill in the blank: The kidneys receive ______% of cardiac output.
20
What are the symptoms of hypercalcemia?
Confusion
Lethargy
Paresthesias
Hypotonia/↓DTR
Irritability
Abd pain
HoTN
N/V
Seizures
Short QT-I
Myocardial depression
Prolonged QT-I
What is the treatment for hyperkalemia?
Dialyze within 24h prior to surgery; initial treatment with calcium; insulin + glucose.
What are the common causes of hypokalemia?
Renal loss
GI loss
Intracellular shift
What is the role of aldosterone in potassium regulation?
Aldosterone causes the distal nephron to secrete K+ and reabsorb Na+.
- Aldo and K+ levels are typically inversely related
What is the normal range for blood urea nitrogen (BUN)?
10-20 mg/dL.
What is the significance of urine specific gravity?
Measures nephron’s ability to concentrate urine; normal range is 1.001-1.035.
What are the signs of acute kidney injury?
Asymptomatic
Malaise
HoTN
Hypovolemic or hypervolemic
What can cause hypercalcemia?
Hyperparathyroid
Cancer
Vitamin D intoxication
Milk-alkali syndrome (Excessive GI Ca++ absorption
What is the treatment for hypocalcemia?
Address underlying cause; consider calcium supplementation.
What are the complications of acute kidney injury?
Neurological issues
Cardiovascular problems
Hematological disorders
What are the symptoms of hypomagnesemia?
Muscle weakness
Seizures
Ventricular dysrhythmia
What is the function of the juxtaglomerular apparatus?
Mediates volume homeostasis; senses changes in volume.
What is the recommended Na+ correction rate for hyponatremia?
Should not exceed 1.5 mEq/L/hr.
What is the danger of rapid correction of hyponatremia?
Can cause Osmotic Demyelination Syndrome, leading to permanent neurological damage.
What are the symptoms of hypocalcemia?
Confusion
Laryngospasm
Seizures
What does the presence of proteinuria (>750mg/day) suggest?
Could suggest glomerular injury or UTI.
What is the primary structural and functional unit of the kidney?
Nephron.
What is the effect of Uremic Encephalopathy on dialysis?
Dialysis improves Uremic Encephalopathy
Uremic Encephalopathy refers to neurological dysfunction due to the accumulation of uremic toxins in the blood.
List some mobility disorders associated with kidney complications.
- Neuropathies
- Myopathies
- Seizures
- Stroke
What are some cardiovascular complications of Acute Kidney Injury (AKI)?
- Systemic hypertension
- Left ventricular hypertrophy
- Congestive heart failure (CHF)
- Pulmonary edema
- Uremic cardiomyopathy
- Arrhythmias
What hematological complications arise from AKI?
- Anemia
- Decreased erythropoietin (EPO) production
- Decreased red cell production
- Decreased red cell survival
- Platelet dysfunction
How does uremia affect von Willebrand Factor (vWF)?
Uremia disrupts vWF
This disruption can lead to coagulation issues.
What is the purpose of prophylactic DDAVP in AKI?
To increase vWF and Factor VIII to improve coagulation
Identify metabolic complications of AKI.
- Hyperkalemia
- Water/sodium imbalances
- Hypoalbuminemia
- Metabolic acidosis
- Malnutrition
- Hyperparathyroidism
What are the anesthesia implications for AKI?
- Correct fluid, electrolyte, acid/base status
- Use normal saline (NS) for volume
- Maintain mean arterial pressure (MAP)
- Consider vasopressors
- Prophylactic sodium bicarbonate
What is the leading cause of Chronic Kidney Disease (CKD)?
Diabetes and Hypertension
What are the stages of Chronic Kidney Disease (CKD) based on GFR?
- Stage 1: GFR > 90 mL/min/1.73m²
- Stage 2: GFR 60-89 mL/min/1.73m²
- Stage 3: GFR 30-59 mL/min/1.73m²
- Stage 4: GFR 15-29 mL/min/1.73m²
- Stage 5: GFR < 15 mL/min/1.73m²
What cardiovascular effects are associated with CKD?
- Systemic hypertension
- Dyslipidemia
- Increased risk of Silent Myocardial Infarction
- Peripheral and autonomic neuropathy
What is the recommended target hemoglobin for anemia management in CKD?
10 g/dL
List indications to consider dialysis.
- Volume overload
- Severe hyperkalemia
- Metabolic acidosis
- Symptomatic uremia
- Failure to clear medications
What are the common side effects of hemodialysis (HD)?
Hypotension (HoTN)
What preoperative assessments should be made for patients with end-stage renal disease (ESRD)?
- Stability of ESRD
- Body weight pre/post dialysis
- Blood pressure control
- Glucose management
- Aspiration precautions
What anesthetic agents should be avoided in patients with CKD?
- Morphine
- Demerol
In general, agents with active metabolites should be avoided becuase of their difficulty clearing the kidneys
What should be monitored in CKD patients undergoing anesthesia?
Renal function and drug dosing based on GFR
True or False: Anesthesia and surgery can decrease renal blood flow (RBF) and glomerular filtration rate (GFR).
t
Fill in the blank: The most common side effect of hemodialysis is _______.
hypotension
What is hyponatremia?
Hyponatremia is characterized by low sodium levels (<125 mEq/L)
Normal sodium levels range from 135 to 145 mEq/L.
What are the symptoms of hyponatremia?
Symptoms include:
* Neurological issues
* Headache
* Nausea
* Vomiting
* Fatigue
* Confusion
* Muscle cramps
* Seizures
* Brain stem herniation
* Respiratory arrest
* Death
More pronounced symptoms appear below 130 mEq/L.
How is hyponatremia treated?
Treatment involves:
* Correcting the underlying cause
* Electrolyte drinks
* Normal saline
* Diuretics
* Hypertonic saline (3% sodium chloride) for severe cases
Treatment must be done slowly to avoid osmotic demyelination syndrome.
What causes hypernatremia?
Hypernatremia is caused by excessive water loss or overcorrection of hyponatremia
Symptoms include orthostasis, restlessness, lethargy, tremors, muscle twitching, seizures, and death.
What are common causes of hypernatremia?
Common causes include:
* Excessive evaporation
* Poor oral intake
* Overcorrection of hyponatremia
* Diabetes insipidus
* GI losses
* Excessive sodium bicarbonate
Treatment involves assessing volume status and addressing the root cause.
What is the normal range for potassium levels?
Normal potassium levels are 3.5 to 5 mEq/L
Less than 1.5% of potassium is found in extracellular fluid.
What are the symptoms of hypokalemia?
Symptoms include:
* Muscle weakness
* Cramps
* Ileus
* Cardiac dysrhythmias
* U wave on EKG
Hypokalemia can be caused by renal potassium loss, GI potassium loss, or transcellular potassium shift.
What are common causes of hyperkalemia?
Common causes include:
* Renal failure
* Hypoaldosteronism
* Drugs affecting renin-angiotensin-aldosterone system
* Depolarizing neuromuscular blockers (Succs can increase K+ by ~0.5)
* Acidosis
* Cell death
* Massive blood transfusions
Symptoms include malaise, GI upset, skeletal muscle paralysis, cardiac dysrhythmias, and death.
What does calcium regulation involve?
Calcium regulation involves:
* Parathyroid hormone
* Vitamin D
* Calcitonin
Hypocalcemia can be a complication of parathyroid surgery.
What are the renal functional labs?
Renal functional labs include:
* GFR
* Creatinine clearance
* Serum creatinine
* BUN
* Urine protein
GFR is the best measure of renal function over time.
What is acute kidney injury?
Acute kidney injury affects 20% of hospitalized patients
AKI Afftects 50% of ICU patients
Common causes include hypotension, nephrotoxic drugs, and IV contrast dye.
What are the three types of acute kidney injury?
The three types are:
* Pre-renal azotemia
* Renal azotemia
* Post-renal azotemia
Treatment involves restoring renal blood flow and maintaining MAP.
What are the stages of chronic kidney disease?
Stages are determined by GFR:
* Stage 1: Normal or increased GFR >90
* Stage 2: Mild decrease 60-89
* Stage 3: Moderate decrease 30-59
* Stage 4: Severe decrease 15-29
* Stage 5: Complete kidney failure <15
Diabetes and hypertension are leading causes.
What are preoperative concerns for kidney patients?
Preoperative concerns include:
* Monitoring potassium levels
* Ensuring dialysis before surgery (24hrs before preferred to allow time for fluid shifts)
* Aspiration precautions
Ultrasound may be required to check stomach contents.
What anesthetics should be avoided in chronic kidney disease?
Avoid anesthetics that are:
* Dependent on renal elimination
* Have active metabolites
Examples include morphine and Demerol.
What is renal dosing?
Renal dosing is based on glomerular filtration rate (GFR)
Specific drugs requiring renal dosing include thiazide diuretics, digoxin, and certain antibiotics.
What are the cardiovascular drug considerations in renal patients?
Considerations include:
* Atropine and glycopyrrolate require renal excretion
* Monitor effects carefully
Both drugs are used together for effective reversal.
True or False: Dialysis is indicated for volume overload in chronic kidney disease.
True
Other indications include severe hypokalemia and symptomatic uremia.
What is the impact of blood loss on renal blood flow?
Blood loss activates baroreceptors, increasing sympathetic outflow
This can lead to acute kidney injury if not managed.
What is the purpose of electrolyte drinks in patient treatment?
They can get the patient back where they need to be.
What is the recommended infusion rate for 3% sodium chloride in treating hyponatremia?
80 mL/hr over about 15 hours.
What is the maximum sodium correction rate to avoid complications?
1.5 milliequivalents per liter per hour.
What condition can result from too rapid correction of sodium levels?
Osmotic demyelination syndrome.
- Rapid correction of NA+ (>6mEq/L in 24hrs) can cause osmotic demyelination syndrome
When is it acceptable to speed up the infusion rate of 3% sodium chloride?
When the patient is experiencing hyponatremic seizures.
Common causes of hypernatremia include excessive evaporation and poor oral intake. Name two more.
- Overcorrection of hyponatremia
- Diabetes insipidus
What are signs of hypovolemia in a patient?
- Tachycardia
- Hypotension
What is the normal potassium level range?
3.5 to 5.0 mEq/L.
What are the three categories of hypokalemia causes?
- Renal potassium loss
- GI potassium loss
- Transcellular potassium shift
What symptoms are commonly associated with hypokalemia?
- Muscle weakness
- Cramps
- Cardiac dysrhythmias
What is a common EKG finding in hypokalemia?
What does the typical EKG progression look like?
U wave.
- Peaked T-Wave
- P-Wave disappearance
- Prolonged QRS
- Sine waves
- Asystole
What is the primary treatment for hypokalemia?
Treat the underlying cause and administer potassium.
What can cause hyperkalemia?
- Renal failure
- Hypoaldosteronism
- Acidosis
What are symptoms of hyperkalemia?
- Skeletal muscle paralysis
- Cardiac dysrhythmias
- Malaise
What is the first line of treatment for hyperkalemia?
Calcium.
- 1st line treatment to stabalize the cell membrane.
Besides calcium, what are some other hyperkalemia treatments?
- Dialyze 24hr prior to surgery
- Hyperventilation (Every increase in pH by 0.1 will decrease K+ by 0.4-1.5mmol/L
- Insulin +/-glucose (10u insulin:25g D50): Works in 10-20min
- Bicarb
- Loop Diuretics
- Kayexelate (hrs to days)
What should you avoid in hyperkalemic patients?
- Succs
- Hypoventilation
- LR and other K+ containing fluids
How does hyperventilation affect potassium levels?
Every increase in pH by 0.1 will drive potassium down by 0.4 to 1.5 mEq/L.
- Bless Dr. Schmidt for teaching us why Alkalosis causes hypokalemia and acidosis causes hyperkalemia.
What should be avoided in patients with hyperkalemia?
- Hypoventilation
- Potassium-containing IV fluids
- Excessive insulin
Where is the majority of the body’s calcium stored?
In the bone.
- Hopefully you didn’t say in the SR. :)
What are the symptoms of hypernatremia?
- Orthostasis
- Restlessness
- Lethargy
What is a complication of rapid sodium correction?
Cerebral edema.
What should be monitored when treating sodium levels?
Sodium levels every four hours.
What can excessive sodium bicarbonate lead to?
Hypernatremia.
What is the recommended sodium reduction rate to avoid neurological damage?
Less than or equal to 0.5 mEq/L/hr.
Less than or equal to 10mEq/L/day
What is kayexalate used for?
kayexalate is a treatment for potassium, driving it out through the GI tract.
What should be avoided to manage potassium levels?
Avoid the following:
* Succs
* Hypoventilation
* Potassium-containing IV fluids
What percentage of the body’s calcium is stored in the extracellular fluid?
Only 1% of the body’s calcium is stored in the extracellular fluid.
Where is the majority of calcium stored in the body?
99% of calcium is stored in the bone.
What is the normal ionized calcium level?
1.2 to 1.38 mmol/L.
How does pH affect ionized calcium levels?
Higher pH leads to more calcium being bound to albumin, lowering ionized calcium levels.
- Increased pH means less H+ ions so there are more availble binding spots for calcium on albumin.
What hormones regulate calcium levels?
The three major hormones are:
* Parathyroid hormone
* Vitamin D
* Calcitonin
What can cause hypocalcemia?
Causes include:
* Drop in parathyroid hormone secretion
* Magnesium deficiency
* Low vitamin D
* Renal failure
* Massive blood transfusions
What are the symptoms of hypocalcemia?
Symptoms include:
* Paresthesias
* Irritability
* Hypotension
* Seizures
* Myocardial depression
What are common causes of hypercalcemia?
Common causes include:
* Hyperparathyroidism
* Cancer
What are the signs and symptoms of hypercalcemia?
Signs and symptoms include:
* Confusion
* Lethargy
* Loss of deep tendon reflexes
* Abdominal pain
* Nausea and vomiting
What are the symptoms of low magnesium?
Symptoms include:
* Muscle weakness
* Seizures
* Ventricular arrhythmias
What is the treatment for Torsades de Pointes?
The treatment is 2 grams of magnesium sulfate.
What are the symptoms of hypermagnesemia at levels above 6 mEq/L?
Symptoms include:
* Hypotension
* Drop in deep tendon reflexes
What is the primary structural functional unit of the kidney?
The nephron.
What percentage of cardiac output do the kidneys receive?
The kidneys receive 20% of cardiac output.
What are the primary functions of the kidneys?
Functions include:
* Regulating extracellular volume
* Regulating extracellular osmolality
* Regulating blood pressure
* Excreting toxins and metabolites
* Maintaining acid-base balance
What hormones are produced by the kidneys?
The kidneys produce:
* Renin
* Erythropoietin
* Calcitriol
* Prostaglandins
What is the normal GFR range?
120 to 140 mL/min.
How does GFR change with age?
GFR drops by 10 mL/min per decade after age 20.
What is the normal serum creatinine level for females?
0.6 to 1.3 mg/dL.
What is the normal BUN range?
10 to 20 mg/dL.
What can affect BUN levels?
BUN levels can be affected by:
* Diet
* Intravascular volume status
What does a high BUN indicate?
Possible kidney damage, high protein diet, dehydration, GI bleed, trauma, muscle wasting
High BUN can also indicate other influencing factors.
What is the normal BUN to creatinine ratio?
10 to 1
Normal BUN should be 10 times the creatinine.
What does proteinuria indicate if greater than 750 mg/day?
Possible glomerular injury or UTI
Normal protein in urine should be less than 150 mg/dL per day.
What does specific gravity measure in urine?
Nephron’s ability to concentrate urine
Higher specific gravity indicates less optimal hydration.
What is considered oliguria in urine output?
Less than 500 mL per day
Normal urine output should be at least 30 mL per hour.
What is acute kidney injury (AKI)?
Deterioration of kidneys over hours to days affecting waste excretion and electrolyte homeostasis
AKI affects about 20% of hospitalized patients.
What are common causes of acute kidney injury?
- Hypotension
- Hypovolemia
- Nephrotoxic drugs
- IV contrast dye
Lack of perfusion to the kidneys is a primary cause.
What does azotemia refer to?
Build-up of nitrogenous waste products such as urea and creatinine
Azotemia and kidney injury are often referred to interchangeably.
What are risk factors for acute kidney injury?
- Pre-existing renal disease
- Advanced age
- Congestive heart failure
- Peripheral vascular disease
- Diabetes
- Sepsis
- Major operative procedures
- IV contrast
These factors can compromise kidney perfusion.
What is the diagnostic criterion for acute kidney injury related to serum creatinine?
Increase by 0.3 mg/dL within 48 hours or 50% increase within 7 days
Trends in creatinine levels are important for diagnosis.
What is pre-renal azotemia?
Lack of perfusion to the kidneys causing necrosis
It is the most common form of acute kidney injury.
What is renal azotemia?
Direct damage to the nephron
Causes include acute glomerular nephritis, nephrotoxic drugs, and acute tubular necrosis.
What is post-renal azotemia?
Obstruction causing back-up and damage to the nephron
Causes include kidney stones, BPH, and bladder tumors.
What is the BUN to creatinine ratio in pre-renal azotemia?
Greater than 20 to 1
Indicates an acute spike in BUN for a given creatinine level.
What is the treatment focus for pre-renal azotemia?
Restore renal blood flow
Hydration and managing blood pressure are crucial.
What does a drop in urine output indicate?
A late sign of body fluid loss
Urine output should be monitored closely.
What is the preferred pressor for maintaining renal perfusion?
Vasopressin
Pressors should be used cautiously to avoid further kidney damage.
What is the significance of a drop in GFR in renal azotemia?
Indicates potential damage to nephron function
A drop in urea reabsorption is also observed.
What is the relationship between pre-renal azotemia and acute tubular necrosis?
Pre-renal azotemia can develop into acute tubular necrosis if not reversed
Timely intervention is crucial to prevent permanent damage.
What is the typical BUN to creatinine ratio for pre-renal azotemia?
Greater than 20 to 1
What causes post-renal azotemia?
Output obstruction leading to increased hydrostatic pressure in the nephron
What is a common diagnostic tool for post-renal azotemia?
Renal ultrasound
How is the reversibility of post-renal azotemia related to the duration of obstruction?
Inversely related; longer obstruction means less reversibility
What is the primary treatment for post-renal azotemia?
Remove the obstruction
What neurological complications can arise from acute kidney injury?
Uremic encephalopathy, neuropathies, myopathies, seizures, strokes
What cardiovascular issues can occur due to acute kidney injury?
Systemic hypertension, left ventricular hypertrophy, heart failure, pulmonary edema, arrhythmias
What hematological effect is commonly observed in patients with acute kidney injury?
Anemia due to decreased erythropoietin production
What metabolic abnormalities are associated with acute kidney injury?
Hyperkalemia, water and sodium imbalances, metabolic acidosis
What is the preferred fluid for kidney patients during anesthesia?
Normal saline
What is the preferred colloid for kidney patients?
Albumin
What type of monitoring is advised for patients with acute kidney injury during anesthesia?
Invasive monitoring, such as an arterial line
What is the leading cause of chronic kidney disease?
Diabetes
What are the stages of chronic kidney disease based on GFR?
Stage 1: GFR > 90, Stage 2: GFR 60-89, Stage 3: GFR 30-59, Stage 4: GFR 15-29, Stage 5: GFR < 15
What is the relationship between hypertension and chronic kidney disease?
Hypertension is both a cause and consequence
What is the effect of ACE inhibitors and ARBs in chronic kidney disease?
Reduce systemic blood pressure and glomerular pressure
Both ACEi and ARBS preferentially relax the efferent arterioles in the kidney
Why should ACE inhibitors and ARBs be withheld on the day of surgery?
To reduce the risk of profound hypotension
What hematological treatment is often used in chronic kidney disease patients?
Exogenous erythropoietin
What are indications for dialysis in chronic kidney disease patients?
- Volume overload * Severe hyperkalemia * Extreme metabolic acidosis * Symptomatic uremia * Inability to clear medications
What is the most common side effect associated with dialysis?
Hypotension
What is the leading cause of death in dialysis patients?
Infection
True or False: Chronic kidney disease is reversible.
False, nephrons do not regenerate
What are common complications of acute kidney injury related to electrolytes?
Arrhythmias due to potassium build-up
Fill in the blank: The GFR decreases by _______ per decade starting from age 20.
10
What percentage of chronic kidney disease cases are attributed to hypertension?
26%
What is a common complication of chronic kidney disease that affects the heart?
Silent myocardial infarction due to neuropathy
What are the complications related to platelet function in chronic kidney disease?
Platelet dysfunction and increased bleeding risk
What can be given preoperatively to kidney patients to help with coagulation?
DDAVP (Desmopressin)
What is the most common side effect associated with dialysis?
Hypotension
Hypotension occurs due to fluid shifts during dialysis.
What is the leading cause of death in dialysis patients?
Infection
Dialysis patients have impaired immune systems and wound healing.
What should be assessed regarding end stage renal disease before anesthesia?
Stability of end stage renal disease and dialysis adequacy
This includes checking electrolytes and trends before and after dialysis.
What body measurement is crucial for drug dosing in dialysis patients?
Body weight
It’s important to distinguish between fluid weight and true body weight.
What should be monitored regarding blood pressure medications in dialysis patients?
Whether they are well controlled and continued
Consider the type of medications, such as ARBs or ACE inhibitors.
What glucose level management is important for diabetic dialysis patients?
Assessing A1C levels
A high A1C can indicate unmanaged diabetes despite normal glucose levels.
What precautions should be taken for aspiration in dialysis patients?
Aspiration precautions due to conditions like diabetes and obesity
Assess gastric contents using ultrasound if possible.
What is a potential complication of using certain anesthetic agents in patients with chronic kidney disease?
Uremic bleeding
Platelet function may be impaired due to uremia.
What is the significance of using Desmopressin (DDAVP) in surgical patients?
It is used prophylactically to manage blood loss
Needs to be administered early due to its peak effect.
What characteristics of anesthetic agents should be avoided in renal patients?
Agents that are lipid soluble and have active metabolites
These can accumulate and cause prolonged effects.
Which opioid medications should be avoided due to their metabolites in kidney patients?
Morphine and Demerol
Both have significant active metabolites that can cause respiratory depression.
What is the elimination half-life of normeperidine?
15 to 30 hours
This long half-life increases the risk of neurotoxicity in kidney patients.
What potassium level is ideal for elective surgery in dialysis patients?
Less than 5.5
This helps prevent complications during the procedure.
What is the recommended time frame for dialysis before elective surgery?
Within 24 hours
Ensures optimal electrolyte balance and fluid status.
What physiological response occurs due to blood loss during surgery?
Increased sympathetic outflow and catecholamines
This can lead to afferent arterial constriction and reduced renal blood flow.
What should be maintained for renal blood flow during surgery?
Mean arterial pressure (MAP) within 20% of baseline
This is critical to prevent acute kidney injury.
