ACUTE RENAL FAILURE

Trish Keresztes, PhD, RN, CCRN

ARF: REVIEW RENAL FUNCTION

Regulate fluid volume. Regulate electrolyte balance. Regulate acid-base balance. Regulate blood pressure. Excrete nitrogenous waste products. Produce erythropoietin. Metabolism of vitamin D.

ACUTE RENAL FAILURE

Precipitous and significant (>50%) decrease in glomerular filtration rate (GFR) over a period of hours to days with an accompanying accumulation of nitrogenous wastes in the body.

ACUTE RENAL FAILURE

Glomerulus: tuft of capillaries. The wall of the glomerular capillary serves as a filtration membrane with three layers– Inner capillary endothelium– Middle basement membrane– Outer layer of capillary epithelium

ACUTE RENAL FAILURE

The glomerular filtrate passes through the three layers of the glomerular membrane and forms the primary urine.

GFR: the filtration of the plasma per unit of time. Directly related to the perfusion pressure in the glomerular capillaries.

ACUTE RENAL FAILURE

Process of urine formation:– Glomerular filtration-> tubular reabsorption-

>tubular secetion->excretion.– Proximal tubules reabsorbs 60-70%

sodium and water and 90% other electrolytes.

– Distal tubules reabsorb sodium, secrete potassium and hydrogen ions (regulate acid base balance.

ACUTE RENAL FAILURE

ACUTE RENAL FAILURE

ACUTE RENAL FAILURE

ARF: RISKS FOR DEVELOPMENT

Hx DM, HTN, CV disease, calculi. Family history calculi, HTN. Hypotensive episodes. Drugs with potential for nephrotoxicity. Major trauma, crushing injuries, severe

allergic reactions.

Acute Renal Failure

Occurs in 4% of all hospital admissions. Occurs in 20% of those admitted into

critical care units. Mortality rate 50% overall. Mortality rate for hospital acquired ARF

is 70%.

Pathophysiology

Glomerular pressure is primarily dependant upon renal blood flow.

Depressed renal blood flow eventually leads to ischemia and tubular cell death.

As tubular cells die, they slough off into the tubules and form obstructing casts which further decrease GFR and lead to oliguria.

ACUTE RENAL FAILURE

Azotemia: refers to an abnormally high level of nitrogenous wastes (urea nitrogen, uric acid, creatinine) in the blood related to a decrease in the GFR.

Uremia: a clinical syndrome that comprises the signs and symptoms associated with end stage renal disease.

ARF CAUSES

Prerenal: decreased blood flow to the kidney.

Intrarenal: Direct damage to the kidney parenchyma.

Postrenal: Obstruction to the flow of urine which may cause hyronephrosis.

Before-within-after the kidney.

ARFPRERENAL CAUSES

Inadequate intravascular volume:hypovolemia– Fluid loss from N/V– Hemorrhage– Excessive diuresis

Redistribution of blood volume– Peripheral vasodilation with sepsis– Third spacing

ARFPRERENAL CAUSES

Reduced cardiac output– Acute MI -> cardiogenic shock– CHF– Cardiac tamponade

Renal artery thrombosis Interruption of blood flow during surgery

ARFINTRARENAL CAUSES

Acute Tubular Necrosis most common form ATN: Prolonged ischemic damage: MAP <60

for 40 minutes Nephrotoxic damage

– Radiographic contrast dye– Drugs: antibiotics (aminoglycosides), NSAIDS– Heavy metals (lead, mercury)

Glomerulonephritis

ARFINTRARENAL CAUSES

Rhabdomyolysis: breakdown of skeletal muscle

Blood transfusion reactions Pesticides Lupus

ARFPOSTRENAL CAUSES

Obstruction due to– Calculi– Blood clots– BPH– Obstruction of indwelling catheter– Tumors

ARFFOUR PHASES

Onset Oliguria (U/O <400ml/day) Diuresis Period of recovery

ARF ONSET

Begins with insult and ends with oliguria Associated with decreased renal blood flow

and GFR and decreased cardiac output. The key is prevention Monitor blood pressure Monitor volume status Monitor cardiac function Monitor labs Identify potential nephotoxins

ARF OLIGURIC PHASE

Obstruction of tubules by cellular debris, tubular casts or tissue swelling.

Total reabsorption of urine filtrate back into circulation.

Renal vasoconstriction ensues.

ARF OLIGURIC PHASE

Can last up to 8 weeks. The longer this phase the poorer the prognosis.

See a volume overloaded patient. Lab values altered. Acidosis. Diet changes. May treat with low dose dopamine.

ARF DIURESIS PHASE

See an increase in urine output. Urine output as much as 1L/hr. Creatinine clearance 15ml/min. Signifies tubular function is returning. Need to monitor volume status-FVD. What happens to lab values during this

phase? What are your concerns?

ARF RECOVERY PHASE

Lasts about six months. ATN irreversible in about 55% of

patients. GFR returns to 70% to 80% of normal

within 1-2 years.

ARF SIGNS AND SYMPTOMS

CNS: lethargy, confusion, tremors, seizures, coma

CV: EKG changes, tachycardia, edema PULM: SOB, rales, frothy sputum with CHF,

rapid respirations (Kussmaul’s) GI: N/V/D GU: urine scant, cloudy, sediment Integ: dry skin, edema, pallor, uremic frost,

pruritis

ARF LABORATORY DATA

BUN Normal BUN:Cr ration is 10:1. If excess in ration of 20:1 suspect dehydration, catabolic state.

Creatinine– Creatinine 1.0 mg/dl: normal GFR– Creatinine 2.0mg/dl: 50% reduction GFR– Creatinine 4.0mg/dl: 70-85% reduction GFR– Creatinine 8.0mg/dl: 90-95% reduction GFR

ARF LABORATORY DATA

Creatinine Clearance– Determines presence and progression of

renal disease.– Estimation of % of functioning nephrons.– Determine medication dosages.

– Calculation= Ucr x V/Pcr

ARF LABORATORY DATA

ABGs Potassium Phosphorus Calcium RBC, HGB

ARF TREATMENT

Correct cause Manage volume status. Correct electrolyte imbalances. Correct acidosis. Treat azotemia: dialysis. Nutritional requirements. Stimulate kidneys: drugs.

ARF HYPERKALEMIA

Kayexalate enema, po Sorbitol retention enema D50W with Humulin R insulin Sodium Bicarbonate IV IV calcium gluconate Dialysis

ARF DIETARY CHANGES

Restrict protein High CHO, fat Restrict fluids Restrict sodium Restrict potassium

ARF MEDICATIONS

Diuretics: lasix, bumex, mannitol Aluminum hydroxide preparations: Calcium replacement Epogen/ iron supplements

ARF: Complications

GI Bleed: occurs in 1/3 of patients with ARF. Accounts for 3% to 8% deaths in patients with ARF.

Pulmonary complications Pericarditis Infections: 33% of patients. Usually

pulmonary or urinary Jaundice

ARF CASE STUDY

61 y/o male admitted to the ER with N/V, abd. pain, general malaise, s/w lethargic, resp’s deep and rapid T99.6, P106 R 32, BP 156/92 +1 edema to mid calves, states he’s not been eating or drinking too much and that he’s had the flu x1 wk. At home meds maxide ?mg. for “blood pressure” and has been taking “a lot” of motrin for aches with the flu

ARF CASE STUDY

LABS: Na 135, K 5.0, Bun 70, Cr 4.3 Ca 8.3, Phos 4.9, H&H 10 &35

ABG pO2 98, pCO2 29,pH 7.30, HCO3 20

What is your impression and why? Identify ALL factors that made you think

of ARF. What phase and what cause?

HEMODIALYSIS

Indications for use:– Acute renal failure– Chronic renal failure– Remove potassium– Remove drugs from overdose– Remove fluids

HEMODIALYSIS

Diffusion: movement of solutes across a semipermeable membrane from an area of higher concentration to lower concentration. Urea, creatinine, potassium.

Osmosis: passage of a solvent or water from area of lesser solute concentration to area of greater solute concentration.

HEMODIALYSIS

Components of hemodialysis– Dialyzer – Dialysate– Vascular access– Hemodialysis machine– Anticoagulation during dialysis

HEMODIALYSISCOMPLICATIONS

Hypotension (need 350cc blood to prime tubing)

Bleeding Infection Heart failure Arrhythmias from hypoxia, hypokalemia

HEMODIALYSISVASCULAR ACCESS

Permanent vascular access AV fistula AV graft tubing Dual lumen Complications: thrombus, infection,

aneurysm formation, ischemia

HEMODIALYSISVASCULAR ACCESS

Temporary access Used for short term dialysis or bridge

until permanent access is available Placed in subclavian, jugular, femoral

veins.

NURSING CAREAV FISTULA/GRAFT

DO NOT take blood pressure in the extremity with the fistula/graft.

DO NOT perform venipunctures in the extremity with the fistula/graft. No IVs.

DO palpate for thrills and auscultate bruits over access.

DO assess for pulses in extremity.

NURSING CAREAV FISTULA/GRAFT

DO elevate extremity. DO check site for bleeding and

infection. DO NOT allow patient to wear tight

clothing or jewelry on extremity. DO NOT let patient sleep on extremity. DO NOT let patient carry heavy objects.

VASCULAR ACCESS

Complications– Infection– Bleeding– Clotting

PERITONEAL DIALYSIS

Good for patient that cannot tolerate HD due to hemodynamic instability, inability to tolerate anticoagulants, and those without venous access

Utilizes principles of diffusion & osmosis

TYPES OF PD

CAPD-continuous ambulatory peritoneal dialysis

MB-CAPD- multiple bag Automated PD IPD-intermittent PD CCPD-continuous cycle PD

Steps of CAPD treatment

Inflow-full bag in (10 minutes) Cloudy outflow Dwell-remains in the abdomen 4-8 hrs Outflow-let gravity drain fluid out (15

minutes) Inflow- start it over again

PERITONITIS

Cloudy outflow Fever Rebound abdominal tenderness General malaise Nausea Vomiting

NURSING CARE

Stress cleanliness in the home Sterile technique with the catheters Dialysate must be room temperature

(cold=cramps) Diet and fluid restrictions are less with

PD Monitor BP (>with FVE, < with FVD)