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% to 25% (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
The lungs and kidneys are the primary regulators of acid-base balance, where the lungs excrete __________ and the kidneys excrete the ___________.
Lungs excrete volatile acids (CO2)
Kidneys excrete non-volatile acids
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
____-% of body weight in non-obese patients is composed of water.
60%
What are the two main fluid compartments?
ECF and ICF
Hyponatremic seizures are a medical emergency and can cause __________ brain damage.
Irreversible
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
________ 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
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.
What is acute renal failure?
Deterioration of renal function over hours to days.
Accumulation of nitrogenous waste products over a short period of time. Difficulty maintaining fluid/electrolyte homeostasis.
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!
What do CRNAs do that causes AKI?
Letting the patient get hypotensive.
What do providers do that can cause AKI?
Contrast
Minimize contrast load, and mitigate with fluids.
What are the risk factors for AKI?
Pre-existing renal disease
Advanced age
Congestive HF
PVD
DM
Sepsis
Jaundice
Emergency Surgery
Major Operative Procedures (Cross-Clamped)
Diagnosing AKI:
Serum creatinine rise > ______ mg/dL
_______% decrease creatinine clearance
Serum creatinine change by _______ mg/dL within 48 hours.
Diagnosing AKI:
Serum creatinine rise >0.5 mg/dL
50% decrease creatinine clearance
Serum creatinine change by 0.3 mg/dL within 48 hours.
Symptoms of AKI
Malaise
Fluid Overloaded
Hypotension
What are the types of AKI?
Pre-renal
Renal
Post-renal
What are the causes of prerenal azotemia (ARF)?
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
What are the causes of renal azotemia (ARF)?
Acute glomerulonephritis
Vasculitis
Interstitial nephritis
ATN
Contrast dye
Nephrotoxic drugs
Myoglobinuria
Real kidney problems. Think infections and inflammation.
What are the causes of postrenal azotemia (ARF)?
Nephrolithiasis (kidney stones, most common cause)
BPH
Clot retention
Bladder carcinoma
UTI- cellular debris
Trauma to the urinary tract
Think mechanical obstruction post-kidney.
Pre-renal azotemia makes up _________ of hospitalized acquired cases.
If pre-renal azotemia is not treated in time, it will progress to _____.
Half (Fortunately, this is rapidly reversible.)
ATN (Swiss cheese kidney tubules)
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 dopamine, mannitol, diuretics, fluids.
Treatment of pre-renal azotemia.
Treat through the restoration of renal blood flow.
Usually, a fluid bolus will be enough to reverse pre-renal azotemia.
Compare diagnostic findings between prerenal oliguria and ATN.
BUN: Cr ratio will be normal in ATN and 20:1 in Pre-renal.
Pre-renal urine will be clear. ATN will have more sediments.
What are the causes of renal azotemia?
Reperfusion injury
Release of cytokines, free radicals, and inflammatory cells
Blockage/obstruction inside the kidney
What will be the BUN: Cr ratio of renal azotemia?
What happens to GFR?
What happens to Urea?
What happens to Creatinine?
Less than 15
GFR will decrease, and nothing will get filtered
Urea does not get reabsorbed; low urea in the blood, high urea in the urine.
Creatinine filtration decreases, leading to higher Cr in the blood.
Neurological complications of AKI.
Uremic Encephalopathy (d/t protein and amino acids in the blood).
Improve with dialysis
List the order of incidence from compilations of CKD:
Pulmonary Edema, LVH, CHF, Systemic HTN
Order of incidence:
1. Systemic HTN
2. LVH
3. CHF
4. Pulmonary Edema
Hematological complications of AKI.
Anemia - d/t decreased RBC production, RBC survival, EPO production, hemodilution
Platelet dysfunction (uremic bleeding) - treat with DDAVP
Metabolic complications of AKI.
Hyperkalemia
Water and Sodium retention
Hypoalbuminemia - responds slower to medication
Metabolic Acidosis
Anesthesia concerns of AKI.
Correct fluid, electrolytes, acid/base status
Maintain MAP
Vasopressors-(consider carefully, and think about where the receptors work).
Prophylactic sodium bicarb - decreases the formation of free radicals and treats academia.
Invasive hemodynamic monitoring and lots of ABGs
Pre-Op dialysis, lower K+ (BZD and opioids might stick around longer in patients until they have dialysis).
Unlike AKI, CKD is progressive and __________.
What is the leading cause of CKD?
Irreversible
DM and HTN
RIFLE Criteria
Describe stages of ESRD and GFR for each stage.
No U/O with stage 4 or 5
Stages 3,4,5 - dialysis-dependent
On average, GFR decreases by ______ per decade starting from age 20.
10
CV effects of CKD.
Systemic HTN (cause and consequence)
Retention of sodium and water
Activation of RAAS d/t decreased GFR
Dyslipidemia (Triglycerides >500, LDL >100)
Silent MI (most prevalent in DM and women)
What are the functions of ACE inhibitors and ARBs?
Why do we want to hold these medications on the day of surgery?
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.
What are the hematological complications of CKD?
Anemia - responds well to EPO, target >10 Hgb
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.
The risk of pre-renal azotemia is reduced by maintaining a MAP greater than _______ mmHg and providing appropriate hydration.
> 65 mmHg
No clear benefit to crystalloids vs. colloids, but _______ are clearly associated with an increased risk of renal injury.
Hydroxyethyl starches (synthetics)
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.
Patients maintained on dialysis should undergo dialysis _______ hours preceding elective surgery.
24 hours
What is TURP?
When is it indicated?
Transurethral Resection of the Prostate.
TURP is indicated for prostate removal in BPH.
Neuraxial anesthesia is common in TURP procedures. The spinal is up to a ______ level.
T10 level
This will allow earlier detection of complications because you can assess the patient’s mentation throughout the procedure.
What are the irrigation fluids used in TURP procedures? List the Pros and Cons of each fluid.
TURP requires continuous irrigation to facilitate visualization. The fluid is absorbed through the open venous sinuses of the prostate. Estimated absorption volume: __________ ml/min.
30 ml/min
Risk for fluid overload and toxicity. TURP syndrome.
The pressure of infusion is influenced by the height of the irrigation solution. The height should be no more than __________ cm above the patient.
60 cm
Cardiopulmonary Sx of TURP.
CNS Sx
Metabolic Sx
Misc Sx
Treating TURP syndrome.
Stop the case
Na+ > 120 mEq/L, fluid restriction and lasix
Na+ < 120 mEq/L give 3% at 100 mL/hr, d/c when Na+ >120 mEq/L.
Complications of TURP
Bladder Perforation
Bleeding
Hypothermia
What are the three types of Urolithiasis?
Nephrolithiasis - Renal Stone
Ureterolithiasis - Ureter Stone
Cystolithiasis - Bladder Stone
What do patients with kidney stones present with?
Intermittent or continuous moderate to severe colicky pain in the ipsilateral flank and upper abdomen
Treatment for kidney stones.
Conservative nonsurgical therapy for smaller stones consists of analgesics (NSAIDS, opioids)
Aggressive fluid administration to promote urine flow and passage of the stone
Medical expulsive therapy (MET)- promotes ureter relaxation and spontaneous passage of small ureteral stones.
ESWL, PCNL, Laser Lithotripsy
What is ESWL?
Absolute contraindications for this procedure?
Extracorporeal Shock Wave Lithotripsy - a machine that will direct energy to the stone.
Pregnancy and high risk of bleeding.
The shock wave of ESWL is timed to the R-wave to reduce the risk of __________.
R on T Phenomenon
Other risks include tissue and internal organ trauma.
What is a PCNL?
Percutaneous Nephrolithotomy.
Place urethral stents and then a nephrostomy tube to access the stone.
Paraplegic patients with a sensory deficit below ______ are at risk for autonomic hyperreflexia and require anesthesia to block afferent stimulation that can provoke this reaction (bladder distention).
Below T6
Patients with a spinal corder injury at _______ or higher are at risk for autonomic hyperreflexia.
T7 or higher
Vascular instability, initially a substantial increase BP above the level of the lesion, followed by overzealous vagal response, with bradycardia, heart block, vasodilation, and flushing
Patients with idiopathic hypercalciuria, treated with _______-
thiazide diuretics
_______ prophylaxis is important, particularly with infected stones or pyelonephritis.
Abx
When lasers are required, appropriate _______ protection for the perioperative team and patient.
eye
Combined blood flow through both kidneys accounts for ______ of total cardiac output.
20-25%
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 (Sch) 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.
What are the three layers of the kidney?
Renal capsule
Renal fascia
Adipose capsule
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
