Exam 3 Electrolytes/Hormones/LABS Flashcards
Inadequate oxygen delivery to the kidney causes it to release ________.
Erythropoietin
Things that can cause decreased O2 delivery: anemia, reduced intravascular volume, and hypoxia.
What can reduce EPO production and lead to chronic anemia?
Severe kidney disease
Calcium requires ________ for adequate absorption and utilization.
Calcitriol (Active Vitamin D)
How does Vitamin D get activated?
Through the kidneys.
What hormone will increase active Vitamin D levels?
PTH
Negative feedback loop
For someone who is chronically anemic what can they take?
Synthetic EPO and Iron to generate more RBC
Long term dialysis patients will be on these medications, dialysis will negate the RBCs.
____-% of body weight in non-obese patients is composed of water.
60%
What are the two main fluid compartments?
ECF and ICF
What are the ways osmolality sensors in the anterior hypothalamus regulate fluid?
Stimulate thirst
Release Vasopressin (ADH)
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
What percent of people in the hospital have hyponatremia?
15%
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
What are treatments for hyponatremia?
Treat underlying causes
Normal Saline
Hypertonic 3% Saline (1 meq/L/hr)
Lasix
Mannitol
Over half of the patients that had their sodium corrected 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?
3-5 mL/kg of 3% saline
Give dose of over 20 minutes
Hyponatremic seizures are a medical emergency and can cause __________ brain damage.
Irreversible
What are the causes of hypernatremia?
Excessive evaporation
Insufficient ADH
Poor oral intake (very young, old)
Overcorrection of hyponatremia
Excessive sodium bicarb to tx acidosis
Be cautious when using sodium bicarb to treat acidosis, what is a good alternative to use if you want to avoid raising sodium?
Tromethamine injection (THAM) is indicated for the prevention and correction of metabolic acidosis.
Effects of hypernatremia
Orthostasis - syncope from standing up
Restlessness
Lethargy
Tremor
Muscle Twitching/ Spasticity
Seizures
Death
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)
Effects 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
IV/PO Potassium
May require days to correct.
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 disease (long-term dialysis pt, fistula)
Insufficient secretion of aldosterone
Acidosis
Tissue/muscle damage
Use of depolarizing NMBD (Succs)
Hypoventilation
With hypoventilation, a pH decrease of 0.1 will cause a ______(range) increase in potassium.
0.4 to 1.5 mEq/L increase in potassium
What are the effects of hyperkalemia?
Potentially asymptomatic
GI upset
Malaise
Skeletal muscle paralysis
Severe cardiac dysrhythmias (cardiac arrest)
Lowers resting membrane potential
Decreases action potential duration
What are EKG presentations of hyperkalemia?
Peaked T-waves (can progress into sine waves if hyperkalemia is severe)
Treatment of hyperkalemia
A BIG DICK
Calcium (stabilize cell membrane) Do this first!
Bicarbonate
Glucose
Insulin (10U and 25g of D50)
Increase RR (hyperventilation!)
Albuterol
Dialysis
What do CRNAs do that can cause hyperkalemia in a patient?
Massive Transfusion Protocol and Blood Products
What are lab tests for renal function?
GFR (best measurement) 125-140 ml/min- great for trends but not for acute states.
Creatinine Clearance (best for acute state) 110-150 mL/min
Serum Creatinine 0.6-1.2mg/dL - estimate of GFR
What is creatinine?
A substance produced by skeletal muscle and is a byproduct of creatine breakdown.
Creatinine production is constant and directly __________ to muscle mass.
proportional
An emaciated individual will probably have a lower creatinine level compared to a bodybuilder. But if you see that a cachectic person has a high creatinine level, it might be a sign that the kidneys are not working well.
Creatinine undergoes renal _________ but not _________, making it a useful indicator of GFR.
Creatinine undergoes renal filtration but not reabsorption, making it a useful indicator of GFR.
100% increase in creatinine indicates a ____% reduction in GFR.
50%
If creatinine goes from 1.2 to 2.4, GFR will decrease by 50%.
Large amounts of protein in the urine may suggest ________ injury.
Labs values and test.
Glomerular Injury
(High levels of protein can also mean UTI and not glomerular injury.)
> 750 mg/day of urine protein or 3+ on dipstick
What are normal BUN ranges?
10-20 mg/dL
BUN can be misleading. Diet and changes in intravascular volume can increase or decrease BUN.
What does specific gravity compare?
What are normal ranges of specific gravity?
Comparing 1 mL of urine to 1 mL of distilled water. Measures the ability of the kidney to concentrate or dilute urine.
1.001-1.035
What is BUN: Creatinine ratio?
10: 1
________ is the primary metabolite of protein metabolism in the liver.
Urea
Because urea undergoes filtration and reabsorption, BUN is a better indicator of ____________ symptoms than as a measure of GFR.
Uremic symptoms
What causes BUN of <8 mg/dL?
Overhydration, too much hydration, dilution.
Decrease Urea production (malnutrition, liver dz)
EtOH patients will forget to eat and get calories just from the booze.
What causes a BUN of 20-40 mg/dL?
Dehydration
Increase Protein Input (high protein, GIB, Hematoma breakdown)
Catabolism (Trauma, Sepsis)
Decrease GFR
What causes a BUN >50 mg/dL?
Decrease GFR
Which lab test is a good evaluation of fluid hydration status?
BUN: Creatinine Ratio
BUN can undergo filtration and reabsorption. Creatinine only undergoes filtration. Because of this reason, the ratio between these substances in the blood is helpful in evaluating hydration status.
A BUN:Cr ratio greater than _________ indicates prerenal azotemia.
20:1
A medical condition characterized by abnormally high levels of nitrogen-containing compounds (such as urea, creatinine, and various body waste compounds) in the blood. It is largely related to insufficient or dysfunctional filtering of blood by the kidneys.
Interchangeable term for Acute Renal Failure
Azotemia
Oliguria definition.
Polyuria definition.
Annuria definition.
Oliguria is decreased u/o (500 mL in 24 hours).
Polyuria is excessive u/o.
Annuriaa is no u/o.
What are the factors that can lead to a false urine specific gravity (SG)?
Look at the big picture and assess the weight of the urine relative to sterile water. SG measures the ability of the kidney to concentrate or dilute urine.
Advanced age
Contrast dye
Abx
Diuretics
Mannitol
Glucose
Proteins
What does a high urine specific gravity indicate?
What does a low urine specific gravity indicate?
More concentrated urine, more solutes.
Less concentrated urine, less solutes.
What number indicates good urine output from an anesthesia standpoint?
30 mL/hr (no standardization for weight and no clinical picture)
0.5-1 mL/kg/hr is more accurate
The normal values for total U/O range between _________and _______ mL in adults with normal fluid intake of 2L during 24 hours.
800 to 2000 mL
What is an early indicator of volume change (arm just got cut off)?
ABG results will quickly indicate volume change.
-Base Excess or Base Deficits will indicate volume loss (Indicator of acid/base balance in the blood).
-Increase in Lactate
H/H will not show the volume loss as quickly.
_________ mL in 24 hours will be called oliguria.
500 mL
CVP trending below _______ mmHg (range) will be volume responsive.
CVP above ________ mmHg (range) will be considered volume overloaded.
5 to 8 mmHg
15 to 20 mmHg
CVP is equivalent to right atrial pressure
_______ is a powerful stimulus for renal vasoconstriction.
Left atrial pressure (wedge pressure)
Increase LAP, increase vasoconstriction. Afferent arteriole will increase to decrease hydrostatic pressure.
What are the criteria for using stroke volume variation in assessing fluid status?
Assume the patient is on positive-pressure ventilation.
Assume the patient is in NSR.
Compare inspiratory and expiratory pressure to assess SVV.
An IVC greater than _______% collapse indicates a fluid deficit.
50%
To assess, place an ultrasound on IVC and perform a passive leg raise, if the quick change in volume dilates IVC, the patient may be in a fluid volume deficit.
If someone with AKI progress to dialysis and multi-system organ failure (MSOF), mortality is now greater than ________.
50% (due to sepsis, CV dysfunction, pulmonary compilations)
AKI is serious shit!
On average, GFR decreases by ______ per decade starting from age 20.
10
Excessive use of 0.9% NaCl leads to ________.
Hyperchloremic Metabolic Acidosis
In healthy patients, what does alpha-1 agonist do to renal blood flow?
Reduce RBF
Septic renal patients will benefit from alpha-1 agonists for MAP support. Increased renal perfusion outweighs the renal vasoconstrictive effects.
Vasopressin preferentially constricts the __________ arteriole. Maintains GFR and UOP better than NE or Neo.
efferent
Renal dose __________ does NOT prevent or treat AKI.
dopamine
Anesthesia concerns of CKD.
Assess the stability of ESRD.
Get the accurate weight of the patient within 24 hrs of surgery.
Well-controlled BP
Glucose management (A1c).
Aspiration Precaution (increase risk)
Uremic bleeding (dysfunctional platelets)
What are treatments of uremic bleeding?
Max effect time:
Duration:
DDAVP - max effect 2-4 hours, last 6-8 hours, give this in pre-op
Cryo (Factor VIII, vWF)
What neuromuscular blockers are not dependent on the kidneys?
Atracurium
Cisatracurium
Hoffman elimination- plasma esterases affected by pH and temperature.
When taking care of renal patients, what medications do we worry about having active metabolite?
Opioids (morphine, meperidine)
Morphine is cleared through the urine, active morphine metabolite will lead to respiratory depression.
Lipid insoluble drugs will have a _________ duration of action in renal patients.
prolonged duration (Thiazides, loop diuretics, digoxin, Abx)
Consider decreasing the dose base off of GFR
What induction medications are excreted by the kidneys?
Phenobarbital
Thiopental
What muscle relaxants are excreted by the kidneys?
Pancuronium
Vecuronium
If kidneys do not excrete them, the liver will.
What cholinesterase inhibitors are excreted by the kidneys?
Edrophonium
Neostigmine
What CV drugs are excreted by the kidneys?
Atropine
Digoxin
Glycopyrrolate
Hydralazine
Milrinone
What antimicrobials are excreted by the kidneys?
Vancomycin
Aminoglycosides
Cephalosporins
PCN
What is the main adverse effect of Demerol?
Demerol has active analgesic and CNS effect.
The main adverse effect is neurotoxicity.
Angiotensin, NE, and ______ influence renal arterial tone.
Epinephrine
The primary source of urea is in the ________.
Liver
Normal serum creatinine concentration for males.
Normal serum creatinine concentration for females
Males: 0.8-1.3 mg/dL
Females: 0.6 - 1.0 mg/dL
Normal creatinine clearance (range): _________
110-150 mL/min
Creatinine clearance measurements for mild renal impairment (range) __________
40-60 mL/min
Creatinine clearance measurements for moderate renal impairment (range) __________
25-40 mL/min
These drugs undergo hepatic metabolism and conjugation prior to elimination in the urine (Select all that apply).
A. Pavulon
B. Benzos
C. Opioids
D. Anectine
A, B, and C
Anectine (Succs) is metabolized by plasma cholinesterase
What is the ideal anesthetic agent for renal patients?
Forane (Isoflurane)
Which kidney is lower?
The right kidney is slightly lower than the left kidney to make room for the Liver
Acceptable urine output in the OR is _____ mL/kg/hr unless the patient is on bypass, then it is ______ml/kg/hr.
0.5 mL/kg/hr (OR)
1 mL/kg/hr (bypass)
Renin is secreted by the _______.
Juxtaglomerular Apparatus
