Exam 3 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?
Nephron
The kidneys receive ______% (range) of CO.
20% (1- 1.25 L)
Besides the kidneys, what organ is retroperitoneal?
Spleen
Primary functions of the kidneys (6 functions).
- Maintain extracellular volume and composition
- Blood Pressure Regulation (Intermed/Long)
- Excretion of Toxins and Metabolites
- Maintain Acid-Base Balance
- Hormone Production (EPO)
- Blood glucose homeostasis
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% TBW
ISF + Plamsa <1/2 volume of TBW
What are the two main fluid compartments?
What is more immediately altered by the kidneys?
ECF and ICF
- ECF
What are the ways osmolality sensors in the anterior hypothalamus regulate fluid?
Stimulate thirst
Release Vasopressin (ADH)
* increase H2O, Na+ reabsorption
ANP released by atria -> kidneys reduce Na+/H2O 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
What percent of people in the hospital have hyponatremia?
Why?
15%
over-fluid resuscitation
increased endogenous vasopressin increased H2) reabsorption (stress response)
The most severe consequence of hyponatremia are these three things:
Seizures
Coma
Death
What are treatments for hyponatremia?
- Treat underlying causes
- Normal Saline
- electrolyte drink
- Hypertonic 3% Saline (80 ml/hr over 15 hrs)… shouldn’t exceed
- 1.5 mEq/L in 24 hrs
- Diuretics
- Mannitol
**check Na+ every 4 hours
Rapid sodium corrected faster than 6 mEq/L in 24 hours can cause __________ syndrome.
What could this result in?
osmotic demyelination
permanant neuro damage
What is the dose and rate of 3% hypertonic saline for patients that are hyponatremic and seizing?
3-5 mL/kg of 3% saline
over 20 minutes until seizure resolves
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
*Excessive Na+ bicarb: tx acidosis - GI losses
- DI: loss of dilute urine
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: NS
Hypernatremic Euvolemic: water replacement (PO or D5W)
Hypernatremic Hypervolemia: diuresis
What is normal potassium level?
ICF or ECF?
3.5 to 5 mEq/L
major intracellular cation
<1.5% in ECF (plasma)
What are the causes of hypokalemia?
Hyperaldosteronism
Diuretics
Kidney disease
Excessive Licorice
HCTZ (BP med)
DKA (frequent urination)
N/V/D
Malabsorption
Intracellular shift: alkalosis, beta-agonists, insulin
Effects of hypokalemia
**Generally, cardiac and neuromuscular
Dysrhythmias, U-wave
Muscle weakness/cramping
Illeus (lose parastalsis)
What changes in EKG will you see with hypokalemia?
U-waves
Treatments for hypokalemia
PO> IV Potassium
IV may require days to correct
K+ 10-20 mEq/L/hr
10 mEq of potassium will increase serum K+ by _____ mEq/L.
0.1 mEq/L
What are the causes of hyperkalemia?
- Renal disease
- Hypoaldosteronism
- Drugs that inhibit RAAS (decrease aldosterone)
- Acidosis
- Tissue/muscle damage
- Depolarizing NMBD (Sux increases K+ 0.5-1 mEq/L)
- Massive blood transfusion
Hyerventilation, a pH increase of 0.1 will cause a ______(range) decrease in potassium
0.4 to 1.5 mEq/L
What are the effects of hyperkalemia?
Potentially asymptomatic
GI upset
Malaise
Skeletal muscle paralysis
Severe cardiac dysrhythmias
* peaked T wave
* P wave disappears
* prolonged QRS
* sine waves
* asystole
Treatment of hyperkalemia
Bicarbonate
Insulin (10U and 25g of D50) +/- glucose
#1 Calcium
Increase RR
Loop diuretics
Kayexalate (hrs-> days)
Albuterol
Dialysis within 24 hr before surgery
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.
Large amounts of protein in the urine may suggest ____ or _____ injury.
Labs values and test.
Glomerular Injury or UTI
>750 mg/day
Normal: < 150 mg/dL
What are normal BUN ranges?
causes of low or high levels?
10-20 mg/dL
BUN can be misleading. Diet and changes in intravascular volume can increase or decrease BUN
urea is reabsorbed into the blood
LOW: malnourished, dilute volume
HIGH: high protein diet, dehydration, GI bleed, trauma, muscle wasting
What does specific gravity compare?
What are normal ranges of specific gravity?
1 mL of urine to 1 mL of distilled water
Measures nephron’s ability to concentrate urine
Normal 1.001-1.035
BUN: Creatinine ratio?
what’s reabsorbed?
Good measure of?
10: 1
BUN reabsorbed
Creat. not reaasborbed
Hydration status
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.
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
_________ mL in 24 hours will be called oliguria.
<500 mL
_______ is a powerful stimulus for renal vasoconstriction.
Left atrial pressure (wedge pressure)
What are the criteria for using stroke volume variation in assessing fluid status?
Assume the patient is on positive-pressure ventilation.
and 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.
What is acute renal failure?
Deterioration of renal function over hours to days.
Failure to excrete nitrogenous waste products or maintain fluid and electrolyte homeostasis
If someone with AKI progress to dialysis and MSOF, mortality is now greater than ________.
50%
What do CRNAs do that causes AKI?
Letting the patient get hypotensive.
What are the risk factors for AKI?
Pre-existing renal disease
Advanced age
CHF
PVD
DM
Sepsis
Hypotension
Jaundice
Major Operative Procedures (Cross-Clamped)
IV contrast
Diagnosing AKI:
Serum creatinine rise > ______ mg/dL within 48 hrs
Increase serum creatinine by ______ within 7 days
_______% decrease creatinine clearance
Abrupt ______, although not always seen in AKI.
> 0.5 mg/dL
50%
50%
Abrupt oliguria
Symptoms of AKI
Asymptomatic
Malaise
Hypotension
hypovolemic or hypervoelmic
What are the types of AKI?
Pre-renal
Renal
Post-renal
What are the causes of prerenal azotemia (ARF)?
BUN: Creatinine ratio?
Treatment?
BUN: Creatinine Ratio > 20:1
still absorbing Na+ and H2O
Hemorrhage
GI fluid loss
Trauma
Surgery
Burns
Cardiogenic shock
Sepsis
Aortic clamping
Thromboembolism
Aortic aneurysm dissection
All these will decrease blood flow to the kidneys
TX: fluids, mannitol, diuretics, pressors
What are the causes of renal azotemia (ARF)?
S/S?
Acute glomerulonephritis
Vasculitis
Interstitial nephritis
ATN
Contrast dye
Nephrotoxic drugs
Myoglobinuria
S/S:
* low GFR (late sign)
* low urea reabsorption in proximal tubule -> low BUN
* high creatinine
* BUN: creatinine < 20:1
What are the causes of postrenal azotemia (ARF)?
Treatment?
Nephrolithiasis (kidney stones, most common cause)
BPH
Clot retention
Bladder carcinoma
TX: remove obstruction
Pre-renal azotemia makes up _________ of hospitalized acquired cases.
Half
Pre-renal = most common AKI
How can you distinguish a pre-renal from an intra-renal AKI?
Pre-renal can reabsorb sodium and water.
*Obtain urine/serum test prior to mannitol, diuretics, fluids
Neurological complications of AKI.
Uremic Encephalopathy
Mobility disorders
Neuropathies
Myopathies
Seizures
Stroke
Related to protein/amino acid buildup in blood
Improve with dialysis
List the order of incidence from compilations of AKI:
Pulmonary Edema, LVH, CHF, Systemic HTN
Order of incidence:
1. Systemic HTN
2. LVH
3. CHF
4. Pulmonary Edema
Hematological complications of AKI.
Treatment?
Anemia
- low EPO production
- low RBC production
- low red cell survival
Platelet dysfunction
vWF disrupted by uremia: treat with DDAVP to increase vWF and fact VIII
Metabolic complications of AKI.
Hyperkalemia
Water and Sodium imbalances
Hypoalbuminemia - responds slower to medication
Metabolic Acidosis
Malnutrition
Hyperparathyroidism: PT glands in overdrive attempting to stimulate kidneys to reabsorb Ca++
Unlike AKI, CKD is progressive and __________.
What is the leading cause of CKD?
Irreversible
DM and HTN
Describe stages of ESRD and GFR for each stage.
Stage 1: often undiagnosed
Stage 4: start dialysis
On average, GFR decreases by ______ per decade starting from age 20.
10
CV effects of CKD.
- Systemic HTN
- Retention Na+ and H2O
- Activation of RAAS d/t decreased GFR
- Dyslipidemia (Triglycerides >500, LDL >100)
- Silent MI (most prevalent in DM and women)
Thiazides: 1st line for HTN
What are the functions of ACE inhibitors and ARBs?
Why do we want to hold these medications on the day of surgery?
Pressors?
Decrease systemic and glomerular hypertension
Decrease proteinuria
Decrease glomerulosclerosis
Hold ACE inhibitors/ARBs on the day of surgery to reduce the risk of intraoperative hypotension.
Pressors: Vaso, NE, Epi
What are the hematological complications of CKD?
Anemia - responds well to EPO, target >10 Hgb
Platelet dysfunction: may need DDAVP
What are the five indications of dialysis?
- Volume overload
- Hyperkalemia
- Severe Metabolic Acidosis
- Symptomatic Uremia
- Medication Overdose
Considerations of dialysis:
HD is more ______ than PD.
PD is more gradual and favored for patients that can’t tolerate __________ associated with HD (CHF/unstable angina).
__________ is the most common adverse event.
_________ is the leading cause of death in dialysis patients.
HD is more effective than PD.
PD is more gradual and favored for patients that can’t tolerate fluid shifts associated with HD (CHF/unstable angina).
Hypotension is the most common adverse event.
Infection is the leading cause of death in dialysis patients.
What are treatments of uremic bleeding?
Max effect time:
Duration:
Side Effect:
DDAVP - max effect 2-4 hours, last 6-8 hours, give this in pre-op
*side effect: tachyphylaxis
Cryo (Factor VIII, vWF)
What neuromuscular blockers are not dependent on the kidneys?
Atracurium
Cisatracurium
Avoid: Sux, Roc
When taking care of renal patients, what medications do we worry about having active metabolite?
Opioids (morphine, meperidine)
Morphine: 40% is cleared through the urine
* active metabolites: morphine 3 glucuronide, morphine 6 glucuronide
* leads to rest. depression
Demerol:
analgesic and CNS effects
AE: neurotoxicity
Half-life 15-30 hrs vs. meperidine 2-4 hrs
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
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
Patients maintained on dialysis should undergo dialysis _______ hours preceding elective surgery.
24 hours
Combined blood flow through both kidneys accounts for ______ of total cardiac output.
20-25%
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 - 1.3 mg/dL
Normal creatinine clearance (range): _________
110-150 mL/min
freely filtered, not reabsorbed: all goes out the kidney
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 (Sch) is metabolized by plasma cholinesterase
What is the ideal anesthetic agent for renal patients?
Forane (Isoflurane)
Volume Homeostasis:
Renin is secreted by the _______.
Juxtaglomerular Apparatus
low volume @ JGA triggers RAAS -> Na+/H2O reabsorption
Na+ 130-135 mEq/L
S/S:
HA
N/V
fatigue
confusion
muscle cramps
depressed reflexes
Na+ 120-130 mEq/L
S/S:
malaise
unsteadiness
same as 130-135:
HA
N/V
fatigue
confusion
muscle cramps
Na+ <120
S/S:
HA
restless
lethargy
seizures
herniation
resp. arrest
Want Na+ reduction rate _____mmol/L per hr and ______mmol/L per day to avoid cerebral edema, seizures, and neurologic damage.
< or equal to 0.5 mmol/L
< or equal to 10 mmol/L
Aldosterone causes distal nephron to secrete _____ and reabsorb _____.
secrete K+
reabsorb Na+
In renal failure, as K+ excretion declines, it shifts towards _______.
GI system
*slower process, reason for high K+
Avoid excess ______, _______, ________, ________, and hypervention in hypokalemia.
**all lower potassium
insulin
beta agonists
bicarb
diuretics
In hyperkalemia:
avoid what neuromuscular blocker?
avoid increase or decrease RR?
avoid what IVF?
avoid SUX
avoid hypoventilation
avoid LR (contains K+)
**All increase K+
Hormones that regulate Ca++
parathyroid: increase GI absorption, increase renal reabsorption, and regulates bone/bloodstream levels
Vit D: augments intestinal Ca++ absorption
Calcitonin: promotes storage in bone
Calcium storage %
normal iCal
iCal affected by?
1% ECF
99% bone
iCal 1.2-1.38 mmol/L
alkalosis -> increased Ca+ binding to albumin -> low Ca+
Causes of hypocalcemia:
low PTH
- increases Ca+ absorption in bones, kidneys, GI
Mag deficiency
- required for PTH production
Low vitamin D
- GI Ca+ reabsorption
Renal Failure
- kidneys don’t respond to PTH
Massive blood transfusions
- citrate binds Ca+
What electrolyte imbalance can cause laryngeal spasms?
Treatment?
low PTH/Ca+
Causes of hypercalcemia:
calcium levels associated
hyperparathyroidism: Ca+ < 11
cancer: Ca+ > 13
Vit D intox.
Milk-alkali syndrome
Granulomatous diseases (sarcoidosis)
HypoMAG:
causes:
S/S:
TX:
low intake
real wasting
muscle weakness/excitation
seizures
vent. dysrhythmias
Torsades: tx 2 Mag
HyperMAG:
causes:
S/S:
TX:
very uncommon, usually due to over-treatment:
- pre-eclampsia/eclampsia
- pheochromocytoma
4-5 mEq/L: lethargy, N/V, flushing
> 6mEq/L: hypotension, decreased DTR
> 10 mEq/L: paralysis, apnea, heart blocks
TX: diuresis, IV Ca+, dialysis
Kidney cortex or medulla recieves more blood flow?
cortex 85-90%
medulla inner layer: more prone to necrosis
Each kidney has how many nephrons?
1 million
What 4 hormones does the kidney produce?
renin
EPO
- RBC production
calcitriol
- maintains serum Ca++
prostaglandins
- inflammatory modulators, vasodilate, increase RBF
Most reliable measure of GFR?
creatinine clearance but need 24 hr urine collection
Serum creatinine can be influenced by?
high protein diet, supplements, muscle breakdown
good for acute monitoring, need a baseline
inversely related to GFR
in acute cases. double SC can mean drop in GFR by 50%
kidney injury leads to _____ lactate, ______ base excess, and ______ is a late sign.
high lactate
low BE
late sign: drop in UO
AKI affects ____% hospitalized patients and ______% ICU patients.
20% hospitalized
50% ICU
2 causes of AKI:
decerased renal perfusion
nephrotoxins
Hallmark of AKI?
Azotemia: buildup of nitrogenous products (urea, creatinine)
Preferred IVF for AKI?
Preferred vasopressors?
want natural or synthetic colloids?
NS
vasopressin > alpha-agonists
*vaso better efferent arteriole vasoconstrictor, maintaining RBF
natural: albumin
Prophylactic bicarb decreases formation of _____ _____ and prevents _____ from causing renal failure.
free radicals
ATN
What does frothy urine indicate?
albumin/protein in the urine
*hypoalbuminemia
What poor side effects can blood transfusions cause?
excess hemoglobin -> sluggish cirulation
acidosis
hyperkalemia
What 2 types of patients need aspiration precautions?
DM and obesity
*decreased GI motility
Best NMB for CKD?
nimbex metabolized in the plasma
Blood loss activates _______, leading to increased SNS outflow.
baroreceptors
Catecholamines activate _______, leading to incrased affarent arteriole construction, decreasing RBF.
alpha 1 receptors
