ACUTE KIDNEY INJURY NOTES QUESTIONS AND ANSWERS

CONCEPT FLUIDS AND ELECTROLYTES Exemplar Acute Kidney Injury ACUTE KIDNEY INJURY NOTES QUESTIONS AND ANSWERS Learning Outcomes • Describe the pathophysiology, etiology, clinical manifestations, and direct and indirect causes of acute kidney injury (AKI). • Identify risk factors associated with AKI. • Utilize the nursing process in providing competent nursing care to the patient with AKI. • Identify therapies used in the collaborative care of individuals with AKI. Questions Review the antecedents of fluid and electrolytes, and answer the following questions: • What role do the kidneys play in the regulation of F&E? • Based on the role the kidneys play in maintaining fluid and electrolyte balance, what would you anticipate happening if these roles became disrupted? • What are the basic components of the kidney, and what role do they have in maintaining renal function? • What would your priority nursing assessments be for a patient with F&E imbalances related to the kidneys not functioning properly? 4 AKI from slight deterioration to severe impairment erized by rapid deterioration of kidney function asCreatinine, BUN, K+ without reduced urine output pment of azotemia Pathophysiology and Etiology of Acute Kidney Failure (AKI) • The causes and pathophysiology of ARF are commonly categorized as prerenal, intrarenal, and postrenal. • Prerenal AKI results from conditions affecting renal blood flow and perfusion. • Intrarenal AKI is characterized acute damage to the renal parenchyma and nephrons. • Postrenal AKI are classified as obstructive causes. Any condition preventing urine excretion can lead to postrenal AKI. Facts about Acute Kidney Failure (AKI) • AKI occurs in approximately one fifth of older adults and may comprise up to 10% of all older adults admitted to acute care settings. • AKI is seen in 2-3% of children cared for in pediatric intensive care units, and up to 8% of infants in neonatal intensive care units. • Potential causes in children and neonates include hemolytic uremic syndrome, acute glomerulonephritis, sepsis, poisoning, hypovolemia, obstructive uropathy, and complication of cardiac surgery, hematologic-oncologic complications, bone marrow transplantation, and respiratory failure. • Children who recover from AKI may have residual kidney damage. RIFLE Classification for Acute Kidney Injury Class GFR Criteria Urinary Output Criteria •R (Risk) Increased serum creatinine 1.5 X 0.5 mL/kg/h for 6 h baseline, OR GFR decreased ≥ 25% •I (Injury) Increased serum creatinine 2 X 0.5 mL/kg/h for 12 h baseline, OR GFR decreased ≥ 50% •F (Failure) Increased serum creatinine 3 X 0.3 mL/kg/h for 24 OR baseline, OR GFR decreased ≥ 75%, OR Anuria for 12 h Serum creatinine ≥ 354 mmol/L with acute rise of at least 44 mmol/L •L (Loss) Persistent acute renal failure = complete loss of kidney function 4 weeks •E (ESKD) ESKD 3 months Pathophysiology of AKI Prerenal Failure • Prerenal Failure – most common – Results from conditions that affect renal perfusion: Hypovolemia • Hemorrhage • Dehydration • Loss from GI tract • Burns • Wounds Low Cardiac Output • Heart failure • Cardiogenic shock Altered Vascular Resistance • Sepsis • Anaphylaxis • Vasoactive medications Pathophysiology of AKI Intrarenal Failure • Intrinsic/intrarenal Failure – Caused by kidney disease Glomerular/microvascular • Glomerulonephritis • Disseminated intravascular coagulation (DIC) • Vasculitis • Hypertension • Toxemia of pregnancy • Hemolytic uremic syndrome Acute Tubular Necrosis (ATN)- primary cause is prolonged ischemia • Ischemia associated with prerenal ARF • Toxins : nephrotoxic drugs, heavy metals, hemolysis (RBC destruction), rhabdomyolysis Interstitial Nephritis • Acute pyelonephritis • Toxins • Metabolic imbalances • Idiopathic Pathophysiology of ARF Postrenal Failure •Postrenal Failure – Obstructive causes of AKI Ureteral Obstruction • Renal Calculi • Cancer • External compression Urethral Obstruction • Prostatic enlargement • Calculi • Cancer • Stricture • Blood clot Risk Factors for AKI • Major trauma or surgery • Infection • Hemorrhage • Severe heart failure • Severe liver disease • Nephrotoxic agents (drugs and radiologic contrast media) • Lower urinary tract obstruction • Age • Child with renal insufficiency 13 Acute Tubular Necrosis » Prevents normal kidney function » Causes – Ischemic – Toxic (Nephrotoxic) » Risk to kidneys high – High blood flow – High O2 requirements – Reabsorption and excretion of metabolites 14 Oliguric Phase Not all AKI has oliguric (low urine output) phase Depends on pathology & cause Pre-renal typically has oliguria, while post-renal has anuria, and intra-renal is non-oliguric The longer the oliguria, the worse the prognosis Onset varies: If cause is ischemic, onset is within 24 hours If cause is nephrotoxic, oliguria develops much later Diuretic Phase High urine output, inability to concentrate urine Initially 1 to 3L/day but as high as 5L/day Nephrons not fully functional High urea concentration causes osmotic diuresis Kidneys can excrete wastes but cannot concentrate urine