Renal Failure

Renal Failure

Rebecca Burton-MacLeodR5, Emerg MedNov 8th, 2007

Overview of RF

Renal Failure

Acute renal failure Chronic renal failure

Acute on chronic renal failure

Acute renal failure

• 2 main renal physiological functions that are easily measured in ED:– Urine output– Excretion of water soluble waste products of

metabolism• Therefore, definition of ARF:

– Decline in Cr clearance of 50%– Increase in serum Cr of 50%– Renal insult causing pt to require dialysis

ARF

• May have anuric (<100cc/24h), oliguric (<0.5cc/kg/h), or non-oliguric renal failure

• Mortality lower with non-oliguric renal failure; however, may still have renal failure with NORMAL urine output!!

Etiology

• Pre-renal (most common; 55% hosp pts)– Intravascular depletion

(hemorrhage, dehydration, diuresis, GI losses, skin losses)

– Vasodilation or dec cardiac output (sepsis, anaphylaxis, nitrates, antihypertensives, liver failure)

• Post-renal (obstruction anywhere along UT)– Renal calculi– Urethral valves– VUR– Cervical Ca or pelvic

inflammation– Prostatic disease

Etiology: renal causes

• ATN (ischemia, rhabdo, toxins—contrast, aminoglycosides, NSAIDs, ACEi, ARBs, tacrolimus, cyclosporine, cisplatinum, heavy metals, ethylene glycol, cocaine)

• Interstitial insult (adverse drug rxn, often assoc with fever, rash, jt pain)

• Glomerular insult (glomerulonephritis)• Vascular insult (renal art thrombosis or stenosis,

renal vein thrombosis, scleroderma)

Differentiating causes

• History:– Hx thirst– GI losses– Hemorrhage, burns,

trauma– Pancreas/liver disease– Meds– Recent illness– Urgency/frequency/

hesitancy in males

• Physical:– Vitals– Volume status– CV—dysrhythmia, s/s

endocarditis– Abdo—aneurysm,

flank tender, bladder size

– Neuro—asterixis, LOC– Derm—rashes, edema

Diagnosing

• Lytes, BUN, Cr• EKG• U/A, Urine lytes• U/S +/- CT KUB

U/A

• Casts:– Hyaline—generally assoc with pre-renal or

post-renal obstructive causes– RBC—always significant; assoc with

glomerulonephritis– WBC—renal parenchymal inflammation– Granular—cellular remnants and debris– Fatty—nephrotic s/o or other nonglomerular

renal disease

Urine lytes

• Urine Na• Fractional excretion

Na– (Urine Na x plasma Cr)

/ (plasma Na x urine Cr)

– Affected if mannitol or loop diuretics administered

• Urine Na <20 and FENa <1%– Pre-renal failure, acute

obstruction, contrast-induced ATN, rhabdo-induced ATN, nonoliguric ATN

• Urine Na >40 and FENa >1%– ATN, chronic obstruction,

underlying CRF

Prevention

• Adequate volume replacement• Foley/percutaneous nephrostomy • Avoid nephrotoxic agents if possible, or

else use OD dosing• Renal-dosing dopamine in conjunction with

lasix may aid in converting oliguric to non-oliguric RF

• Consider low-dose vasopressin in sepsis

Management of specific problems

• HyperPh: give oral Ca antacids which bind to Ph

• Symptomatic hypoCa: 10cc of 10% Cagluconate IV

• HyperK: if >6.5 and EKG changes…be aggressive!

• Volume overload: diuretics, nitrates, dialysis

Indications for dialysis with ARF

• Fluid overload in oliguric/anuric RF• HyperK• Severe acidemia• Uremic encephalopathy• Toxins: ethylene glycol, methanol, ASA,

Li, theophylline

Prognosis in ARF

• If receive dialysis for ARF then 16% remain dialysis-dependent

• Also, 40% of pts develop CRF

Chronic renal failure

• Definition: – CRF—GFR <60cc/min, but decreased by <75%– ESRD—GFR <10cc/min, serious life-

threatening complications without dialysis or transplant

Etiology • DM (45%)• Hypertension (30%, up to 40% in black popn)• Glomerulonephritis• Collagen vascular disease (SLE, scleroderma, Wagners)• Hereditary (PCKD, Alports s/o)• Obstructive uropathy (BPH, retroperitoneal tumor,

nephrolithiasis)• HIV• Nephrotoxins (contrast, heroin, ampho B, aminoglycosides)• Peds—reflux nephropathy

Complications

• Uremia• Renal osteodystrophy• Normocytic normochromic anemia• Infections (impaired WBC function)• GIB (stress ulcers and impaired hemostasis)• Pericarditis (up to 20% of dialysed pts)

What ? Do you need to ask…

• Dry weight?• Dialysis schedule?• Form of dialysis (hemo, peritoneal)?• Missed dialysis?

Mgmt of specific disorders

• Cases…

Case 1

• 68yo F with sharp lower abdo pain x2d, worsening. Small amount of blood in stool this a.m.

• You’re convinced you need a CT abdo. Speak to Radiol. They ask what her Cr is…

• ….long pause…..142….• Do you still want CT? What are your

options?

Contrast nephropathy

• Risk factors—DM, underlyling renal d/o, amyloidosis, MM, hypo-proteinuric states, larger doses of contrast, repeat exposures to contrast <72hr, type of contrast

• NAC?• Bicarb?

Papers…

• Several studies done looking at benefit of NAC vs. bicarb vs. saline for prevention of contrast nephropathy

• N=264; received either bicarb infusion, or N/S infusion, or NAC and N/S infusion

• 6 hrs pre and post angio• Baseline Cr 139• Change in Cr clearance significantly better

with bicarb than with other regimens

Cont’d

• DBRCT n=326 pts undergoing angio• All had chronic renal disease• Protocols: 1) N/S x12 hrs pre and post and

NAC 2) bicarb x1h pre and 6h post and NAC 3) N/S and ascorbic acid and NAC

• All pts had NAC day prior to procedure and days after

Cont’d

• Outcome:– In N/S and NAC: 9.9% developed CN– In bicarb and NAC: 1.9% developed CN– In N/S and ascorbic acid and NAC: 10.3% CN

– Bicarb and NAC significantly better in medium to high risk pts for CN

• N=118 with Cr >110• Bicarb 3ml/kg/h x1h prior then 1ml/kg/h

x6h post vs. N/S infusion as above• Significantly greater nephroprotective

effects from bicarb• Postulated due to inc flow, local tubular

alkalinization, partial correction of ischemic acidosis

Case 2

• 72yo M presents c/o chest pain, weakness. At triage, HR noted to be 32.

• Brought back to monitored bed.• Hx of DM, hypertension, recent w/u for

back pain• Meds: metformin, lasix, propanolol,

penicillin, one other med he can’t remember the name of…

Case cont’d

• O/e: HR 34, SBP 86, RR 16, sats 93%• Pt pale, slightly diaphoretic; nil else

remarkable on exam• BG—6.8• Plan?

EKG

Any thoughts ?

Plan ?

Case cont’d

• ABG– K 9.8• Cr 589

HyperK in RF• CaCl 5cc IV bolus, rpt q5min prn

– ?is he on digoxin?• Bicarb 50meq IV, rpt x1 prn

– Watch for volume overload!!• Ventolin nebs, rpt or continuous• Insulin—give 10-20U Hum R mixed with glucose

– Use D20 or D50 to decrease volume• Kayexalate, mixed with sorbitol

– Watch for Na overload as exchanges K for Na• IV diuretics

– Only works if residual renal function!• Dialysis!!!

How quickly will K drop?

• Insulin drops K by 1meq/L after 1h• IV Ventolin drops K by 1.1meq/L after

15min• Dialysis:

– Hemodialysis—removes up to 50meq/h– Peritoneal dialysis—removes 15meq/h

Case 3

• 47yo F hemodialysis patient presents to ED c/o SOB

• Last dialysis 5d ago (missed one because travelling back from US); states weight up 6lbs

• O/e: HR 110, BP 145/87, sats 88% r/a• Tachypneic, ++crackles to bilat lungs, elevated JVP• You call her Nephrologist…waiting for them to get

back to you…• Plan?

Pulmonary edema

• Hemodialysis…• Oxygen, sitting position• Consider CPAP• Nitrates: SL, IV or nitroprusside• Lasix 60-100mg IV (for pulm vasodilation)• +/- IV morphine• Sorbitol 70% 50-100cc dose q20-60min (causes

osmotic shift into gut)• Hemodialysis…

Case 4

• 59yo M presents to ED c/o cough, SOB, fever x3d

• Mild chest pain, no abdo pain, no n/v• PMHx: hemodialysis pt, DM, pacemaker• O/e: HR 115, SBP 95, RR 30, sats 95% r/a• Slight JVD, normal HS, lungs clear, abdo

soft• Investigations?

CXR

Old XR (1y ago) Today

EKG

Uremic pericarditis

• Aggressive volume support• Indomethacin • Hemodialysis ++++++• +/- pericardiocentesis (if unstable)• +/- steroid instillation

Case 5

• You get a call from dialysis unit. They’re mid-way thru a run of HD with a pt who has now developed hypotension. They can’t get a hold of Nephro and are not sure what to do with the pt.

• You asked if they’ve slowed the rate and amount of ultrafiltration (duh!)…

• They want to send him down to ED…

Cont’d • Before the pt even arrives, you’re thinking Ddx:

– Hypovolemia (dialysis related, GIB, hemorrhage)– CV causes (MI, dysrhythmias, tamponade)– Lyte d/o (Ca, Mg, K)– Air embolism– Hypoxemia– Drugs (narcotics, antihypertensives, anxiolytics)– Hypersensitivity rxn (to ethylene oxide which sterilizes

dialyzer, polyacrylonitrile in the membranes)– Autonomic neuropathy– Acetate-based dialysate

Mgmt of hypotension

• Obviously, decrease flow rate and amount of ultrafiltration

• N/S IV bolus: 250-500cc in small boluses of 100-200cc and frequently reassess!

• Try to figure out why…

Case 6

• 86yo F presents to ED c/o high BP. Says she takes her BP at home regularly and today it was 195/115. She’s been told this is “too high”. You go in to take a quick hx…nothing exciting. Nurse has not checked pt in yet.

• O/e: NAD. Lungs nil acute. CV nil acute. Abdo nil acute. Skin—note made of Cimino-Brescia fistula in L arm with thrill present

• You ask for a set of vitals and disappear to see your next pt…

Cont’d

• You come back a while later and find the BP cuff cycling q1min measuring her BP…last one 158/90.

• It’s cycling on her L arm…any problem?• You check her fistula site and notice there

is no longer a thrill, but still feel a strong palpable pulse. Concerned?

Thrombosis of access

• Avoid manipulating access site, as may cause venous embolization

• Call Vascular• Occasionally they may use thrombolytic agents to

open thrombosed access but usually surgical revision required

• Bottom line: don’t put tourniquet, check BP, or circumferential bandages on arm with fistula!!

Case 7

• 43yo M presents to ED c/o generalized abdo pain, malaise. He has a peritoneal dialysis line in place. Last seen by Nephro about 3wks ago, everything going well. Very conscientious about his peritoneal catheter and keeping it sterile!

• ROS: small amount of foul urine produced, diarrhea x1 yest, sore throat ~1wk ago

Cont’d

• O/e: T 38.2, HR 92, BP 142/78, sats 98%• Lungs clear, HS normal, H+N small

cervical lymphadenopathy, abdo sl distended, catheter site appears clean, mild abdo tenderness, no guarding, no rebound

• Investigations?

Cont’d

• CBC, lytes, Cr, lipase• Dialysate analysis• U/A

Results

• WBC 12• Lytes N, Cr 327, lipase N• U/A--+RBC, +leuks, +WBC and granular

casts• Dialysate—cloudy, 105 WBC, 60% neuts,

Gm stain pending

Peritonitis

• 70% of cases caused by staph aureus or staph epidermidis

• If polymicrobial infection, then suggests direct contamination from GI tract and should search for perf or fistula!

• Usually can be easily treated as oupt and does not require removal or replacement of catheter

Mgmt

• Intraperitoneal abx x10-14d:– Vanco 30mg/kg IP q5-7d– Ceftazidine 1gm IP q1d– Gentamicin 2mg/kg IP then 20mg/L q1d

• Don’t forget to think about other intra-abdo causes of peritonitis!!