Renal Flashcards
How to reduce contrast induced nephropathy?
Use less contrast
nonionic, iso-osmolar, low in viscosity contrast
antioxidant: NActeylcysteine, ascorbic acid
bicarb infusion to alkaline urine (3ml/kg/hr for 1 hr prior and 1ml/kg/hr for next 6 hrs
How to reduce contrast rxn in patient with contrast allery?
50mg prednisone 13 7 and 1 hr prior to contrast
50mg diphenhydramine 1 hr prior to dye
Benefit of fenoldopam?
selective dopamine agonist thought to reduce incidence of acute post op renal failure in pt undergoing major vascular surgery and/or recieving contrast dye.
systemic vasodilation in dose dependnt manner (unlike dopamine) while preserving/augmenting renal blood flow.
rapid onset, fast metabolism, good drug for treating severe blood pressure in pts w renal impairement
Don’t admin unless also attempting to reduce blood pressure
CI to extracorporeal shock wave therapy
pregnancy
bleeding diathesis
urinary obstruction below stone
UTI
relative: obesity, aortic aneusrym, orthopedic device, pacemaker
issues with dorsal lithotomy position for turp
-elevated preload
elevate intrabominal pressure and impaire resp fxn
LE nerve injury
How to deal with post op acute renal failure
- Post renal: Check foley for obstruction
- Pre-renal causes: hypovolemia (fluids), hypotension (vasopressors), CHF (inotropes/diuretics)
- Intrinsic: consult nephrologist, consider dialysis if necessary, usually self limited 7-14 days
- Limit any further injury: no contrast, NSAIDs, nephrotoxic agents
Issues with water bath for lithotripsy? General issues
submerged in warm water–>vasodilation–>hypotension
water hydrostatic pressure –>HTN (blood redistributes to central circ), and reduction FRC
arrythmias
alveolar rupture w hemoptysis
How to limit dysarrthmias with lithotripsy
stop procedure
check direction of shock wave
check timing on EKG (R wave)
reduce energy of shock if possible
Why creatinine a good measure of GFR
What does BUN:CR ratio> 10:1 indicate
secreted and not reabs by kidney. takes days to demonstrate acute decline in GFR, confounded by diuretics
usually produced by conditions of decreased tubular flow (hypovolemia, CHF, cirrhosis)
Level of spinal needed for lithotripsy?
T6-Renal is T10-L2 (excessive diaphragm movemement can interfere w procedure
diuretics
head to toe Chronic renal failure concerns
neuro: urremic encephalopathy, peripheral/autonomic neuropathy,
cards: accelerated CAD, fluid overload, CHF, HTN, pericarditis, arrythmias, autonomic neuropathy, conduction blockade
resp: pulm edema, pleural effusion
GI: delayed gastric empyting; bleeding,
endocrine:
- hyper: K, mAg, Po4, uric acid
hypo: na ca, hypoalbumin,
met acidosis
heme: anemia (low EPO), plt and WBC dysfunction
endocrine; insulin resistance, 2 hyperparathyroidism , high TG
RBF autoregulation
What reduces GFR
80-180
NE, Epi, Angiotensin 2, symathetic activation
drugs affected by chronic renal failure
decreased protein binding–>enhanced drug effect: barbs and benzo, etomidate:
active metabolites dependent on renal excretion: keta,ine, morphine, meperidine,
increased BBB permeability and uremic toxins, effects anesthetics may be enhanced
How to view hyperkalemia and case canceing
- severity and chronicity
- need to proceed w surgery: avoid factors that would further hyperK-hypovent, acidosis, succ, K containing fluids
- 5 reasonable
etiology of anemia
How is renal failure anemia compensated for etiology
How can plt dysfunction be treated
decreased EPO, GI bleeding, vit def,
right shift oxy hemoglobin dissociation curve & increased 2,3 DPG
DDAVP desmopressin–>release factor 8 and WVF
How does chronic renal failure affect my intraoperative course
- eval volume status: hypervolemic bf dialsysis and hypo after. consider invasive monitors dependning on severity of coexisting dz and surgery
- consider rapid seq due to delayed gastric emptying
- avoid drugs heavily dependent on renal elim. cisatra vs roc balanced technique with fent midaz and inhalat first choice.
- if pt at risk for additonal renal damage, ensure adequate hydration and perfusion
- avoid hypervent (shift hemoglobin oxygen curve to left, and hypoventiation (hyper)
How to perserve renal fxn in ARF
- prevention bc mortality as high as 50%
- ensure adequate hydration
- avoid nephrotoxic agents: aminoglycosides, contrast, NSAIDS,
- consider renal; protective agents
protential but unproven renal protective agents
dopamine- D1 D2 agonist-renal vasodilation
fenoldopam-D1 agonist -vasodilation, increase RBF and GFR, naturesis and diuresis
mannitol: osmotic diuresis, may relieve tubular obstruction caused by sloughed off endothelail cells, free radical scavanger
furosemide: causes diuresis NAK2CCL), may reduce demand by blocking resportion
N acetylcysteine: antioxidant-protect againist contrast dye nephropahy
ANP: synethetic ANP-increases GFR
How to eval causes of acute renal failure
- postrenal: eval foley consider irrigating
- pre-renal: look for signs of hypovolemia/hypotension increased renal vascular resistance, fluid bolus if can tolerate fluid otherwise diuretic/inotrope, consider lasix to wash out slouh off epithelail cells that could cause obstruction
- renal: ischemia, nephrotoxins, intrinisc dz, ATN (FENA>2
How to assess volume status in RF
Dialysis: last dialysis, compare weights,
vitals, UOP, CXR
signs hypervolemia: HTN, pulm edema, peripheral edema, JVD
signs hypovolemia: hypotension, tachycardia, orthostasis, dry mucous membranes
how to manage fluids during transplant?
concern with blood transfusion in pt with transplanted kidney. how blood should be processed before transfusion.
important to maintain adequare intravascular volume and mainatin renal blood flow to reduce post op ATN and promote early onset graft fxn: isotonic fluids 3:1 ratio
If blood necssary admin washed/leukoreduced, irradaiated (reduce risk transfusion graft vs host, CMV neg pack red blood cells
exposure to leukocyte antigens in blood may lead to development of alloantibodies predisposing to rejection
meds given during kidney transplant
heparin before clamping to prevent clotting
manniol and lasix to promote diuresis and in case mannitol free radical scavanger
How to treat hyperkalemia.
EKG signs
peaked T widened QRS, prolonged PR)
-get code cart and treat according to ACLS
calcium: cardiac membrane stabilize immediate effect
shift extracellular K into cell: insulin/glucose (10-20min), B2 agonist (albuterol), sodium bicarb (less acidosis), hyperventilate (alkalosis)
Why CRF pts a risk for bleeding
heparin used during dialsysis, plt dysfxn
When would you cancel a case for hyponatremia? At what level is it dangerous why?
- Urgency surgery
- Lab value, Baseline, chronic or acute
- Signs sx of hyponatremia
- Neuro: fatigue, lethargy, H/A, confusion, irritable, restlessness, AMS
- Cardiac: cardiopulm arrest
- GI: N/V
- Cerebral edema, seizure, coma, brain stem herniation (brain swelling <130
What is HRS
Life threatnning renal failure that develops in ESLD and ascites with eleavted creatinine >1.5. characterized by vasoconstriction of renal vasculature, decreased GFR, preserved tubular fxn, hyperosmolar urine, urine sodium <10, azotemia, normal renal histology
diagnosising HRS?
renal fxn that improved w fluid challeneg of 1.5l Albumin likely pre renal
urinary sodium>10 meq granular casts ATN
Major
- advanced liver dz and portal HTN
- low GRF (serum creatine >1.5 creatinine clearance <40
- absence of shock, infection, fluid loses, tx w nephrotoxic agents
- no improvement in renal fxn to a 1.5 L fluid challange
- absence of proteinuria, <500mg/day urinary obstruction, renal paranechymal dz
minor: oliguria <500ml/24 hr, low urine sodium <10 mEq, urine osm>serm osm, spotaneous dilutional hyponatremia (sodium <130), absence RBC in urine
pathophysiology HRS
types
tx
-endothelail (NO and prostcyclin), glucagon -increased levels of vasodilators lead to splanic vasodilatin–>reduced effective volume sensed by kidney–>RAAS + sympathetic NS, –>persistant vasodilation splanchnic circc and reduced perfusion of kidney results in profound intrarenal arterial vasoconstriction –>HRS
HRS 1- rapidly progressive creatinine >2.5 cc <20ml/in in less than 2 weeks
HRS 2: creatinine >1.5
medical tx: albumin (volume expansion), midodrine (vasoconstritor), octreotide (inhibitor splanchic vasodilation), transplant
How does pneumoperitoneum cause oliguria
- decreased CO–>increased secretion ADH
- sympathetic induced release of catecholamines–>avtivate RASS
- release of inflammatory mediators can result in AKI
concerns about bicarb admin
- generation of Co2which can diffuse into cells worsening intracellular acidosis
- L ward shift of oxyhemoblobin diss curve increasing hemoglobins affinity for oxygen and decreased unloading
- hyperosmolar state 2/2 to excessive sodium
- hypokalemia 2/2 movement K from extracellular to intracellular space
post op polyuria
tx DI
DI: hypoosmolar fluid-l
mobilization of third space fluid
diuretics
osmotic diuresis from hyperglycemia
tx:
ow sodium-1/2 NS or D5W (DDAVP)-hyperatremia
DDAVP
D5-1/2NS at normal maintenance rate plus 2/3 of prev hours UOP. Do not replace full uop, and monitor for hyperglycemia. If fluid requirements exceed 350-400ml/hr consider giving DDAVP.
drugs to avoid inRF
morphine, ketamine, meperidine (cerebral irritants)
decrease dose of benzo 2/2 exaggerated drug effect
