Renal labs extra from oral Flashcards
PT, PTT, bleeding time in CRF, reason and Tx
- increased bleeding despite normal PT, PTT, and BT- cause is defective vWF Give DDAVP 0.3-0.4mg/Kg over 30 minutes or cryo, also have blood warmer ready to go
Hyperkalemia common, what EKG changes does it produce
Peaked T, long PR, long QRS, ST depression HB and V-fib can result
HyperMg leads to
CNS depression and coma
high or low pH in CRF
low, can’t excrete H+ ions
CXR for
HTN CV disease, pericardial effusion, uremic pneumonitis
Dig tox EKG
Short QT, ST depression
Hypocalcemia EKG
Long QT
RF and drugs
Anemia, low serum protein, e-lyte changes, fluid retention, changed cell membrane dynamics all affect drugs Drugs excreted by the kidney unchanged are CONTRAINDICATED, like gallamine, phenobarbital
Common anesthetic drugs to use with caution in RF
Thiopental- high PB Midazolam- 60-80% renal clearance, high PB Dexmedetomidine- high PB
Opioid of choice in RF
Fentanyl Remi also ok
Bad opioids in RF
Meperidine, morphine, hydromorphone
Muscle relaxants to avoid in RF
d-tubo, metocurine, gallamine, pancur, pipecur, doxacur Vec, roc ok (30% renal), but may see longer effect
Extra caution with succs because
K is released! Only use if K is normal, but probably want to avoid it
What is the most common cause of high BUN
CHF secondary to the reabsorption of BUN Low CO causes lows kidney perfusion. Kidneys try to correct perceived fluid deficit by reabsorbing urea.
Why is anemia common in renal failure?
1) Decreased EPO production 2) Build-up of toxins decreases the lifespan of RBCs
Chronic renal patients will usually have an increased or decreased CO?
Increased to compensate for the anemia
Hemoglobin levels as low as __-__ are common for renal patients, so don’t freak out
5-8
Renal patients usually have fucked up coags. Which coags are fucked up and why?
PT, PTT, and bleeding time. These are fucked up because they have shitty vWF. Treat this by replacing vWF.
How can you treat the fucked up coags seen in renal dysfunction?
Replace the vWF! 1) Desmopressin .3-.4mg/kg over 30 min) - Desmopressin will increase the release of vWF from endothelial cells 2) Cryoprecipitate (remember that this contains factor VIII, XIII, fibrinogen, and whaddup –> vWF!)
The hyperkalemia seen in RF can result in these EKG changes
Peaked T waves, ST depression, prolonged PR interval and QRS complex, heart block, and V-fib
Hypermagnesemia resulting from RF can cause
Coma and CNS depression Prolongs the duration of NMBs
Why do we use a microdripper to give fluids in renal patients?
To make sure we don’t fluid overload them
Why does RF cause HTN?
1) Renin release by the diseases kidney 2) High intravascular fluid volume d/t inappropriate handling of sodium and water
RF can lead to ____ pericarditis and cause
uremic pericarditis tamponade
Hypocalcemia causes this on EKG
Prolonged QT
Digitalis toxicity produces this on EKG
Shortened QT and depressed ST
These meds are excreted via the kidneys unchanged and are contraindicated in RF
Gallamine (100% renal elimination) and phenobarbital
Is UO predictive of post-op renal insufficiency?
No
What can happen if you give too much fluid to your anuric renal patients?
CHF and pulmonary edema
UO during surgery should be maintained at this rate
0.5cc/kg/min If it falls, we can give 5mg of lasix
A 50% increase in plasma creatinine means
A 50% reduction in GFR
This is the source of creatinine
Skeletal muscle
We are concerned about K+ when it is over
5
When is vasopressin released?
Released by the posterior pituitary in response to high serum osmolarity and acts on the kidneys
This is the dose for low-dose dopamine
1-2mcg/kg/min
Effect of neuraxial anesthesia in renal dysfunction
• T4-T10 sympathectomy will decrease the release of catecholamines, renin, and vasopressin (ADH) o This is because we’re causing vasodilation and blocking the sympathetic response! o Make sure to pre-hydrate before placement! • Key to maintenance of renal blood flow and GFR is you have to maintain renal perfusion pressure – fluid boluses etc. o Remember that proper RBF is dependent on MAP
Effect of PPV on renal function, and how we can over come this
• The higher the PIP and PEEP the greater the decrease in RBF, GFR, and urine flow rate o Probably because PPV will decrease venous return and CO We can overcome this by hydrating.
Creatinine Clearance
Normal is 125mL/min •
What may a CXR show in the patient with renal failure?
• LVH o Determine presence of hypertensive cardiovascular disease • Pericardial effusion (from uremic pericarditis) • Uremic pneumonitis- RF patients have chronic pulmonary edema → fluid overload, shitty heart function, and leaky capillaries
Avoid these NMBs in renal failure
d-tubocurarine, metocurine, gallamine
What is the most common cause of death in renal failure?
Infection Make sure to use aseptic technique!!
IAs for RF
Halothane Avoid- High K+ & acidosis-> myocardial irritability Enflurane Avoid- fluoride concern Sevoflurane Controversial: some practitioners remain concerned regarding Compound A and fluoride Isoflurane/Desflurane Volatile agents ideal-no dependence on kidney for elimination Accelerated induction and emergence seen with severe anemia Anemia results in decreased solubility of the IA
Ventilation goals in RF
Hypoventilation exacerbates acidosis Hypercapnia predisposes to cardiac arrhythmias from acidosis Alkalosis shifts oxy-hgb curve to left- less O2 available to tissues Overall, we want to maintain normal acid/base balance Remember too that they are anemic and we want to do this to keep the O2 dissociation curve to the right!! Remember that high PIP and PEEP will decrease RBF
This is the pressor of choice for renal pts
Ephedrine
What’s the deal with H2 blockers and renal failure?
H2 blockers are highly dependent on renal excretion
