Nephro Exam 3: LE AKI + RRT (CONDENSED)

AKI diagnosis and staging

• KNOW (KDIGO diagnosis): any ONE of the following

  • SCr increase > _____ mg/dL within _____

  • SCr > _____x baseline within _____

  • Urine output < _____ mL/kg/hr for _____

0.3, 48 hours, 1.5, 7 days, 0.5, 6 hours

AKI diagnosis and staging

• Any degree of AKI increases risk of death. Survivors often develop CKD or need RRT.

• Timelines: AKI < _____, AKD < _____, CKD > _____ (CKD = GFR < _____ mL/min/1.73m2 and/or albuminuria, most common).

• Acute presentation is _____. Chronic is more than _____

7 days, 3 months, 3 months, 60, hours to days, 3 months

PRE-renal (_____)

• _____: hemorrhage, vomiting, diarrhea, burns

• _____: HF, massive PE, cardiac tamponade

• _____: decrease efferent arteriole constriction, which lowers glomerular pressure

• _____: decrease afferent arteriole dilation

• _____

Decreased renal perfusion, Hypovolemia, Decreased CO, ACEi/ARBs, NSAIDs, CNIs

INTRINSIC (_____ within the kidney)

• Caused by ischemia, toxins, or inflammation. Can be vascular or glomerular damage.

• KNOW ATN (_____): _____ are aminoglycosides, iodinated contrast, cisplatin, amphotericin B, mannitol

• KNOW AIN (_____): _____ (beta-lactams, PPIs, NSAIDs, vancomycin, diuretics) and infection

structural damage, tubular, nephrotoxins, interstitial, drugs

POST-renal (_____)

• KNOW _____: KIDNEY STONES (nephrolithiasis). Bladder outlet obstruction (BPH) also listed in review.

• KNOW _____ or _____ (crystal nephropathy): _____, _____, _____ drugs. CRYSTALS form when patients do not drink enough water.

urine flow obstruction, Ureteral Obstruction, Renal Pelvis, Tubular Obstruction, Acyclovir, MTX, sulfa

Subjective of AKI

• Dark or discolored urine, anuria

• Weight GAIN, edema, fatigue, malaise

• Fever, rash, arthralgia, flank or abdominal pain

• Dehydration, vomiting or diarrhea, illness, infection, surgery, hospitalization

• KNOW MEDS: Rx and OTC drugs, herbals, _____ (_____, _____, _____, _____, illicit drugs)

nephrotoxins, NSAIDs, ACEi/ARBs, antibiotics, IV contrast

Objective of AKI: BMP

• KNOW Normal ranges: Na _____, BUN _____, K _____, CO2 _____, SCr _____

• In AKI, _____, _____, and _____ rise

• BUN:SCr ratio above 20:1 suggests _____. About 15:1 suggests _____.

• SCr is a waste product of muscle metabolism and lags 1-2 days behind the actual GFR decline.

135-145, 8-25, 3.5-5.0, 22-29, 0.6-1.5, K, BUN, SCr, Pre-renal, Intrinsic

Urine output

• Goal: _____ mL/kg/hr. Example: a 70 kg patient needs more than 35 mL/hr (420 mL over 12 hours).

• Oliguria: < _____ mL/day. Anuria: < _____ mL/day. Polyuria: > _____ L/day.

0.5, 400, 50, 3

Urinalysis and urine electrolytes

• KNOW Fractional excretion of Na (FENa): pre-renal < _____%, intrinsic > _____%

1, 2

Test	PRErenal	INTRINSIC	POSTrenal
Urine sediment	_____ casts, may be normal	_____ casts, _____	_____
Urinary RBC	_____	2-4+	Variable
Urinary WBC	_____	2-4+	1+
Urine Na	_____ mEq/L	_____ mEq/L	_____ mEq/L
FENa	_____%	_____%	_____
BUN:SCr	_____	_____	_____
UCr:SCr	_____	_____	_____

GO BY COLUMN

hyaline, negative, negative, <20, <1, >20:1, >40:1, Granular, cellular debris, >40, >2, 15:1, <20:1, Cellular debris, >40, Variable, 15:1, <20:1

Test	PRErenal	INTRINSIC	POSTrenal
Urine osmolality	_____ mOsm/kg	_____ mOsm/kg	_____ mOsm/kg
Specific gravity	_____	_____	_____
Protein	_____	Mild to moderate (mild < _____ g/day, moderate _____ g/day)	_____

>500, >1.018, Negative, <300, <1.012, 0.5, 0.5-3.0, <300, Variable, Negative

Prevention of AKI

• No therapy reverses AKI. Prevention is the goal.

• Avoid unnecessary contrast and nephrotoxic drugs. Adjust drug dose and duration to kidney function.

• Pre- and post-procedure hydration for contrast or surgery.

• Glycemic control.

• Identify at-risk patients and avoid kidney insults.

KNOW

Contrast-associated AKI (CA-AKI)

• Onset within 48 hours of IV iodinated contrast.

• Risk factors: eGFR < 30 mL/min, comorbidities, concurrent nephrotoxins.

• KNOW _____: use the lowest effective dose of low- or iso-osmolar contrast, HOLD _____

• KNOW _____ starting 1 hour _____ and continuing 3-12 hours _____ contrast

• KNOW _____ and _____

Prophylaxis, nephrotoxins, NS, before, after, N-acetylcysteine, Na Bicarb

Treatment of AKI

• Stabilize perfusion and maintain MAP above 65 mmHg. Prevent complications.

• Pre-renal: restore perfusion and volume (_____, hemodynamic support)

• Intrinsic: remove _____, manage _____

• Post-renal: relieve obstruction (_____, _____, _____ correction)

• Review meds. Stop or substitute nephrotoxic agents, or adjust dosing.

IV crystalloids, toxins, inflammation, catheterization, stent, surgical

Renal replacement therapy (RRT) indications: AEIOU

• A: _____ (pH _____)

• E: _____ (severe _____, _____)

• I: _____ (salicylates, LITHIUM, ethylene glycol, METHANOL)

• O: _____ (pulmonary EDEMA unresponsive to diuretics)

• U: _____ (ENCEPHALOPATHY, PERICARDITIS)

• Also start for urgent indications or when refractory to medical management. Starting early without an indication adds risk without benefit.

• Modalities: IHD and CRRT. Goal is to remove toxins and fluid and correct acid-base status.

acidosis, <7.2, Electrolyte Imbalance, HYPER-K, HYPER-Mg, Intoxication, Overload, Uremia

PK changes in kidney disease

• Absorption: _____

• Distribution: _____. _____ protein binding of acidic drugs gives a _____ free fraction.

• Metabolism: non-renal (_____) clearance

• Elimination: _____ clearance, so _____ half-life

decreased, unchanged or increased volume, lower, higher, hepatic, lower, longer

When to adjust

• Drugs mostly eliminated by the _____ (example: _____)

• _____ therapeutic index drugs (_____, _____, _____)

• _____ metabolites cleared by kidneys (_____, _____, _____)

• Two ways to adjust: _____ the dose OR _____ the interval

kidneys, vancomycin, Narrow, digoxin, dofetilide, lithium, active or toxic, morphine, codeine, meperidine, reduce, extend

Loading vs maintenance doses

• _____ dose depends on Vd. Do NOT reduce it for kidney function. _____ and _____ can INCREASE Vd.

• _____ dose depends on CLEARANCE. Reduce the dose or extend the interval.

• Protein binding: _____ albumin or _____ means _____ free (active) drug (example: phenytoin)

Loading, sepsis, fluid overload, Maintenance, low, uremia, more

Estimating kidney function for dosing

• KNOW Cockcroft-Gault: use adjusted body weight when actual weight is more than _____ of ideal body weight. Rounding up SCr in older adults is not supported by evidence.

• 2021 CKD-EPI eGFR: add _____ for abnormal muscle mass or NARROW therapeutic index drugs (digoxin, dofetilide, lithium).

• Low muscle mass means low _____, so it may overestimate kidney function.

130%, cystatin c, SCr

High-yield renal dose adjustments (KNOW)

• Antimicrobials

  • _____: NEUROTOXICITY when not adjusted

  • _____ and _____: neurotoxicity, CRYSTAL nephropathy

  • _____: INCREASES SCr w/o a true GFR DECREASE. Also causes HYPER-K.

• _____ and _____: BLEEDING

• _____, _____, _____: SEDATION, falls, encephalopathy

• _____ and _____: ACTIVE metabolites. Prefer _____ or _____.

• _____, _____, _____: NARROW therapeutic index, ARRHYTHMIA

• _____: LACTIC acidosis. _____: HYPO-GLYCEMIA.

• _____: start low and titrate

Cefepime, Acyclovir, Valacyclovir, TMP-SMZ, Enoxaparin, Dabigatran, Gabapentin, Pregabalin, Baclofen, Morphine, Codeine, hydromorphone, fentanyl, Digoxin, Dofetilide, Sotalol, Metformin, Glyburide, Allopurinol

NOOOO renal adjustment needed (KNOW)

• Antibacterials: _____, oxacillin, nafcillin, linezolid, _____, _____, _____, _____, _____, _____

• Other antimicrobials: micafungin, _____, remdesivir

Ceftriazone, Doxycycline, Minocycline, Azithromycin, Moxifloxacin, Metronidazole, Clindamycin, voriconazole

DOAC dosing in AFib

• Use Cockcroft-Gault CrCl, EXCEPT _____

• _____ if 2 of 3 criteria: age _____ or OLDER, weight _____ kg or LESS, SCr _____ or HIGHER

Apixaban, Apixaban 2.5 mg BID, 80, 60, 1.5

Common renal dose adjustments

• _____ (Tx and prophylaxis), _____, _____, _____ (zoster), _____

Pharmacist renal dosing protocols

• Renal dose adjustment is done per pharmacy protocol by CrCl band. Document the change.

Enoxaparin, Gabapentin, Levetiracetam, Valacyclovir, Sitagliptan

Unstable kidney function

• In the first _____ of AKI, kidney function is not stable. Monitor closely. Risk of overdosing, and during recovery, risk of underdosing.

• Kinetic eGFR estimates GFR from _____ values.

• At the bedside, use the SCr trend and urine output, not a single value.

• Starting a med: give the _____ dose. Continuing a med: reduce the _____ dose using CrCl from today's SCr.

24-48 hours, 2 SCr, loading, maintenance

Vancomycin in AKI

• _____ dose uses Vd (_____)

• During AKI, _____ lags behind true _____. _____ dosing is harder.

• Once SCr stabilizes, use _____-guided dosing.

• Case 6 answer: a level that barely falls, with very low urine output, means almost NO CL. Treat kidney function as CrCl under 10. Cockcroft-Gault overestimates clearance in anuric AKI. Hold scheduled dosing, redose by levels, and involve nephrology if RRT is indicated.

Loading, actual BW, SCr, GFR, Maintenance, AUC

Augmented renal clearance

• CL _____ than normal

• KNOW High-CrCl labeling: _____ is not for _____ if CrCl _____ mL/min. Cefiderocol needs more FREQUENT dosing if CrCl _____ mL/min.

Recovery

• Increase doses back toward normal as kidney function recovers.

• Restart held meds when _____ and _____ are stable.

higher, edoxaban, AFib, >95, >120, volume, SCr

RRT Basics

• RRT is a _____ bridge for severe AKI, or ongoing treatment for _____.

• RRT replaces: _____ balance, _____ balance, _____ CL.

• RRT does NOT replace: EPO (_____), _____ activation (_____), _____ and other BP hormones.

• _____ is preferred over _____.

• _____, _____, _____ protein binding, _____ Vd drugs are the MOST dialyzable.

temporary, kidney failure, fluid and electrolyte, acid-base, solute and drug, anemia, Vitamin D, CKD-MBD, renin, IHD, CRRT, small, water-soluble, low, low

Modality comparison

• _____: HOURS per session, 3x/WEEK. HIGHEST CL per hour and highest HYPOTENSION risk. Good drug dosing data. Used in ICU, floor, clinic, or home. Best for STABLE patients.

• _____: longer, SLOWER sessions, usually DAILY. Hybrid of IHD and CRRT. Intermediate clearance and hypotension risk. ICU ONLY. Limited drug dosing data. Used when CRRT is unavailable or stepping down from CRRT.

• _____: CONTINOUS 24 HOURS per day. LOWEST CL per hour and LOWEST HYPOTENSION risk. ICU ONLY. Good drug dosing data. Best for UNSTABLE ICU patients.

• Choose CRRT for: hemodynamic _____ (on _____), cerebral _____ or _____ ICP, large daily fluid needs.

• Choose IHD for: hemodynamic _____, _____ removal (life-threatening _____, _____ ingestion), kidney failure on _____.

IHD, SLED, CRRT, instability, vasopressors, edema, high, stability, rapid, HYPER-K, toxic, chronic dialysis

CRRT modes

• _____: convection, needs REPLACEMENT FLUID, removes SMALL AND MIDDLE molecules

• _____: DIFFUSION, needs DIASYLATE, removes mostly SMALL molecules

• _____: removes SMALL AND MIDDLE molecules

• REPLACEMENT fluid can be given before (pre) or after (post) the _____.

CVVH, CVVHD, CVVHDF, filter

Dialysis circuit and dialyzer

• _____ is pumped out through the access. _____ is given. _____ passes through the dialyzer.

• _____: thousands of hollow fibers of semipermeable membrane. Blood flows _____ the fibers. Dialysate flows COUNTERCURRENT to blood to keep the gradient _____.

• Dialysate for IHD: machine-mixed (_____, _____, _____) or premade sterile bags.

• Molecular size determines removal: small (_____), middle or high-flux (_____, some cytokines), large (_____, _____ protein-bound drugs, _____ cells). _____ size or protein binding means _____ removal.

blood, Heparin, blood, Dialyzer, inside, high, K, Ca, Dextrose, aminoglycosides, vancomycin, albumin, highly, blood, increasing, less

Vascular access

• _____: TEMPORARY catheter

• _____: AV FISTULA preferred

• _____: high INFECTION and THROMBOSIS risk

• _____: if it CLOTS or has LOW FLOW, use ALTEPLASE to restore flow

• KNOW _____ is a complication to watch for

• Create a PERMANENT AV access about _____ dialysis, since FISTULAS take _____ to mature.

AKI, Kidney Failure, Central Venous Catheter, AV Graft, Local Infection, 1 year before, months

Catheter locks and patency (KNOW)

• Clearing an occluded catheter: forced _____, _____ in each lumen, dwell _____, then _____.

• Not working: _____ the dose

• Still occluded: _____.

saline flush, Alteplase 2mg/2mL, 30 mins, aspirate, repeat, catheter exchange

Circuit anticoagulation

• UFH: _____-mediated. Main risks are _____ and _____.

• KNOW Regional citrate: citrate _____ ionized _____ needed for clotting. _____ stays in circuit, so bleeding risk is lower. Main risk is _____. Give _____ or _____. Citrate is converted to _____, and _____ is infused back.

antithrombin, bleeding, HIT, chelates, Ca, anticoag, HYPO-Ca, Ca Gluconate, Chloride IV, Bicarb, Ca Citrate

CRRT complications

• _____: replace with replacement fluids

• _____

Intradialytic complications

• Intradialytic _____: most common HD complication. Main cause is removing _____ fluid _____.

• _____ from aggressive fluid removal or electrolyte shifts. Prevention: _____ (best evidence) or _____.

• Intradialytic _____: volume, RAAS activation, dialysis, removal of BP medications

• Other: _____-type reactions, _____ (from heparin)

Electrolyte Losses, HYPO-PO4, Hypotension, too much, too quickly, muscle cramps, Vitamin E, Gabapentin, HTN, allergic, bleeding

Chronic HD adequacy

• Reach _____ weight (_____ after HD)

• Remove enough waste. _____ is the marker.

• More is not better.

Peritoneal dialysis (PD)

• Uses the peritoneum as the membrane. _____ removes solutes.

• _____ therapy. CAPD uses manual exchanges during the day and a long overnight dwell.

• PD peritonitis: diagnosis needs at least 2 of 3 criteria: _____ and/or _____ effluent, WBC above _____ with more than _____ neutrophils, _____ effluent culture.

• Treatment: start _____, intraperitoneal (IP) preferred, empiric initially.

dry, no edema, urea, diffusion, home, abdominal pain, cloudy, 100, 50%, positive, antibiotics

Dialysis options and transitions

• Options: in-center HD, home HD, or PD (choose by patient preference, lifestyle, comorbidities). Often a bridge to transplant. Lifelong UNLESS transplanted.

• Conservative care (_____): slows CKD progression, focuses on Sxs, for older or frail patients and goals of care.

• Patients can move between options.

• Prepare at CKD stage _____. Start _____ for Sxs.

• Stop _____ for kidney recovery. The pharmacist re-checks the dose of every renally cleared drug at each transition.

no dialysis, 4, dialysis, RRT

RRT terms

• _____: a few hours per session

• _____: sustained low-efficiency dialysis, longer and slower

• _____: continuous, 24 hours

• _____, _____, _____: continuous venovenous filtration, dialysis, and diafiltration

• _____: peritoneal dialysis

IHD, SLED, CRRT, CVVH, CVVHD, CVVHDF, PD

Drugs and dialysis (KNOW)

• Removed by dialysis: _____, _____, most _____, _____, _____, _____

• Give dialyzable drugs _____.

• Vancomycin loading: _____ 25 mg/kg, _____ 20-25 mg/kg. Vd is _____ L/kg x _____ BW.

• Spot dosing by level: dose (mg) = (_____ - _____) x _____

• High-flux HD removes a _____ fraction each session. Redose _____.

• Pre-HD vancomycin level (draw BEFORE HD), then dose after HD:

  • < _____ mg/L: increase the dose

  • _____ mg/L (goal): continue the current dose

  • > _____ mg/L: reduce or hold the dose

• Dosing principles: the biggest CRRT error is antibiotic _____dosing.

• Move antihypertensives to the evening or after HD.

• CKD Med management: phosphate binders, insulin, HYPER-K (check diet and meds), high pill burden and nonadherence, frequent readmissions (do medication reconciliation).

Vancomycin, Aminoglycosides, beta-lactams, levetiracetam, gabapentin, lithium, after HD, IHD, CRRT, 0.7, actual, target level, current level, Vd, large, after HD, 15, 15-20, 20, under

Renal replacement therapy (RRT) indications: AEIOU

• A: Acidosis (pH _____)

• E: Electrolye imbalance (severe _____, _____)

• I: Intoxication (_____, _____, _____, _____)

• O: Overload (_____ unresponsive to _____)

• U: Uremia (_____, _____)

<7.2, Hyper-K, Hyper-Mg, Salicylates, Lithium, Ethylene Glycol, Methanol, Pulmonary Edema, diuretics, encephalopathy, pericarditis