Spring 2024 (Exam III) Renal Assessment Flashcards
The kidneys sit retroperitoneal between _______ and _______.
Which kidney is slightly more caudal (lower) to accommodate the liver?
T12 and L4
Right
What is the functional unit of the kidney and what are its components?
- Nephron
Glomerulus
Tubular system - Bowman capsule
- Proximal Tubule (PCT)
- Loop of Henle
- Distal Tubule (DCT)
- Collecting duct
The kidneys receive ________% (range) of CO
The _____ _____ receives the majority of RBF (85-90%)
- 20% (1 L)
- Outer Layer
*LOH particularly vulnerable for developing necrosis in response to HoTN ((↓kidney perfusion)
Besides the kidneys, what organ is retroperitoneal?
Spleen
Primary functions of the kidneys (6 functions).
- Maintain extracellular volume and composition (RAAS and ANP)
- Blood Pressure Regulation (Intermed/Long)
- Excretion of Toxins and Metabolites
- Maintain Acid-Base Balance (excretion of HCO- and H+
- Hormone Production (Renin, Erythropoietin, Calcitrol, PGs)
- Blood glucose homeostasis (Gluconeogenesis and glucose reabsorption)
Calcium requires ________ for adequate absorption and utilization.
Calcitriol (Active Vitamin D)
How does Vitamin D get activated?
Through the kidneys
What hormone will stimulate the release of Ca++ from the bones and which hormone promotes storage of Ca++?
PTH; Calcitonin
____-% of body weight in non-obese patients is composed of water.
about 60%
What are the two main fluid compartments?
ECF and ICF
Per this lecture ECF is _______ the volume of TBW.
< 1/2 volume of TBW
____ ____ is mainly mediated by osmolality-sensors in anterior hypothalamus
Osmolar homeostasis
_____ _____ is mediated by juxtaglomerular apparatus
Volume homeostasis
What are the ways osmolality sensors in the anterior hypothalamus regulate fluid?
- Stimulate thirst
- Release Vasopressin (ADH)
- Cardiac atria releases ANP→ act on kidney to ↓Na+/H20 reabsorption
What are ways JGA regulates fluid?
- ↓Vol @ JGA triggers Renin-Angiotensinogen-Aldosterone system (RAAS)→Na+/H20 reabsorption
What is a normal sodium level?
135-145 mEq/L
There are no absolute cut offs for sodium level for surgery, but these numbers will be a good reference.
Na level below _________ mEq/L and above _______ mEq/L are a no go for surgery.
Below 125 mEq/L
Above 155 mEq/L
What are some causes of hyponatremia?
- Prolonged sweating
- Vomiting/diarrhea
- Insufficient aldosterone secretion
- Excessive intake of water
- Burns
- Trauma
What percent of people in the hospital have hyponatremia and why?
- 15%
- over fluid-resuscitation
- ↑endog vasopressin
There are two patient populations where we are most concerned about sodium levels.
Neuro patients
Kids
The most severe consequence of hyponatremia are these three things:
- Seizures
- Coma
- Death
hypervolemic hyponatremia cause
ARF/CKD heart failure (majority)
hypovolemic hyponatremia cause
generally due Na+/H20 loss (diuretics, gi loss, burns, trauma)
euvolemic hyponatremia cause
salt restriction, endocrine related -Hypothyroid, SIADH (holding on to H20 >Na+)
What are treatments for hyponatremia?
- **Treat underlying causes **
- Normal Saline
- Hypertonic 3% Saline
- Lasix
- Mannitol
What is the correction rate when supplementing Na with 3% saline?
- Na+ correction should not exceed 1.5 meq/L/hr
- Dose: 80 mL/hr over 15h
Rapid correction of Na faster than 6 mEq/L in 24 hours can cause __________ syndrome.
What could this result in?
osmotic demyelination
Seizures, coma, death
What is the dose and rate of 3% hypertonic saline for patients that are hyponatremic and seizing?
- Medical Emergency
- 3-5 mL/kg of 3% saline
- Give dose of over 20 minutes until seizures resolve
Hyponatremic seizures are a medical emergency and can cause __________ brain damage.
Irreversible
What are the causes of hypernatremia?
- Excessive evaporation
- Poor oral intake(very young, old)
- Overcorrection of hyponatremia
- Diabetes Insipidus
- GI losses
- Excessive sodium bicarb to tx acidosis
Symptoms of hypernatremia
- Orthostasis
- Restlessness
- Lethargy
- Tremor/ Muscle Twitching/ spasticity
- Seizures
- Death
What is the recommended Na+ reduction rate and what are the side effects if reduced too quickly?
- ≤0.5 mmol/L/hr and ≤ 10 mmol/L per day
- Cerebral edema, seizures, and neurologic damage
Treatments for hypernatremia?
First, assess volume status (tachycardic, hypotensive, u/o, skin turgor, CVP, SV variation)
Then treat the cause.
Treatments for the following.
Hypernatremic Hypovolemia:
Hypernatremic Hypervolemia:
Hypernatremic Euvolemic:
Hypernatremic Hypovolemia: normal saline
Hypernatremic Hypervolemia: diuretic
Hypernatremic Euvolemic: water replacement (PO or D5W)
What is normal potassium level?
3.5 to 5 mEq/L
Patients will not go to surgery if potassium is less than ______ or greater than _______ mEq/L.
K+ less than 3 mEq/L
K+ greater than 5 mEq/L
What are the causes of hypokalemia?
Excessive release of aldosterone
Diuretics drugs (Lasix, hydrochlorothiazide)
Kidney disease
Excessive intake of licorice (kids eating too much licorice.)
DKA (frequent urination)
3 major categories for hypokalmeia cause
renal loss
GI loss
transcellular shift
s/s of hypokalemia
Generally, cardiac and neuromuscular (K+ of 2mEq/L)
Dysrhythmias (K+ of 2mEq/L)
Muscle weakness
Cramps (Eat a banana)
Paralysis
Illeus (lose parastalsis)
What changes in EKG will you see with hypokalemia?
U-waves
You will see this on the exams and boards.
Treatments for hypokalemia
- Treat the underlying cause
- PO > IV Potassium
May require days to correct
Avoid excessive insulin, β-agonists, bicarb, hyperventilation, diuretics
10 mEq of potassium will increase serum K+ by ________ mEq/L.
0.1 mEq/L
Why may PO potassium be faster in increasing serum potassium levels?
A larger dose can be given PO compared to 10-20 mEq/hr with IV.
When replacing potassium levels, what other electrolytes do you need to keep an eye on?
Phosphorus (normal levels 2.5 - 4.5 mg/dL)
Who are at the most risk of dysrhythmias when getting potassium replacement?
CHF patients
Digoxin patients
What are the causes of hyperkalemia?
Renal failure
Hypoaldosteroinism
Drugs that inhibit RAAS
Drugs that inhibit K-secretion
Use of depolarizing NMBD (Succs)
Acidosis (Resp./ Metabolic)
Cell Death (trauma, tourniquet)
Massive Blood Transfusion
With hyperventilation, a pH increase of 0.1 will cause a ____ in potassium.
0.4 to 1.5 mEq/L decrease in potassium
Succynlcholine will increase serum K by ______
about 0.5-1.0 mEq/ L
s/s hyperkalemia?
- Potentially asymptomatic
- GI upset
- Malaise
- Skeletal muscle paralysis, ↓fine motor
- Severe cardiac dysrhythmias (cardiac arrest)
What are EKG presentations of hyperkalemia?
Peaked T-waves (can progress into sine waves if hyperkalemia is severe)
* P wave disappearance
* Prolonged QRS
* sine waves
* Asystole
Treatment of hyperkalemia
- Dialyze within 24h prior to surgery (can also cause hypovolemia)
- Calcium- 1st initial treatment (quickly stabilize cell membrane)
- Hyperventilation (↑pH by 0.1 →↓K+ by 0.4-1.5 mmol/L)
- Insulin +/- glucose (10u IV: 25g D50) * works in 10-20 min
- Bicarb
- Loop Diuretics
- Kayexalate (hrs to days)
- *Avoid Succs, hypoventilation, LR & K+ containing IV fluids
What do CRNAs do that can cause hyperkalemia in a patient?
Massive Transfusion Protocol and Blood Products