Chapter 26

A patient with acute kidney injury (AKI) has been started on continuous venovenous hemodialysis (CVVHD). The nurse knows the hemodialyzer filter used in this type of therapy is permeable to what substance? a. Electrolytes b. Red blood cells c. Protein d. Lipids

ANS: A A continuous venovenous hemodialysis filter is permeable to solutes such as urea, creatinine, uric acid, sodium, potassium, ionized calcium, and drugs not bound by proteins.

To remove fluid during hemodialysis, a positive hydrostatic pressure is applied to the blood and a negative hydrostatic pressure is applied to the dialysate bath. What is this process called? a. Ultrafiltration b. Hemodialysis c. Reverse osmosis d. Colloid extraction

ANS: A To remove fluid, a positive hydrostatic pressure is applied to the blood, and a negative hydrostatic pressure is applied to the dialysate bath. The two forces together, called transmembrane pressure, pull and squeeze the excess fluid from the blood. The difference between the two values (expressed in millimeters of mercury [mm Hg]) represents the transmembrane pressure and results in fluid extraction, known as ultrafiltration, from the vascular space.

A patient was admitted with an infection that had to be treated with gentamicin, an aminoglycoside antibiotic. After 3 days of administration, the patient developed oliguria, and an elevated blood urea nitrogen and creatinine levels. The nurse suspects the patient has developed what type of kidney injury? a. Prerenal b. Intrarenal c. Anuric d. Postrenal

ANS: B Any condition that produces an ischemic or toxic insult directly at parenchymal nephron tissue places the patient at risk for development of intrarenal. Ischemic damage may be caused by prolonged hypotension or low cardiac output. Toxic injury reaction may occur in response to substances that damage the kidney tubular endothelium, such as some antimicrobial medications and the contrast dye used in radiologic diagnostic studies.

The practitioner has ordered continuous renal replacement therapy (CRRT) for a patient with acute kidney injury. The patient needs both the removal of fluids and a moderate amount of solutes. Which type of CRRT would the nurse anticipate being started on this patient? a. Slow continuous ultrafiltration (SCUF) b. Continuous venovenous hemofiltration (CVVH) c. Continuous venovenous hemodialysis (CVVHD) d. Continuous venovenous hemodiafiltration (CVVHDF)

ANS: B Continuous venovenous hemofiltration (CVVH) is indicated when the patient's clinical condition warrants removal of significant volumes of fluid and solutes. Fluid is removed by ultrafiltration in volumes of 5 to 20 mL/min or up to 7 to 30 L/24 h. Removal of solutes such as urea, creatinine, and other small non-protein-bound toxins is accomplished by convection.

A patient with acute kidney injury (AKI) has been started on continuous venovenous hemodiafiltration (CVVHDF). The nurse understands the patient should be closely monitored for what circuit-related complications of the therapy? a. Hypervolemia, hypothermia, and hyperkalemia b. Access dislodgment, decreased outflow pressures, and bleeding c. Filter clotting, access failure, and air embolism d. Increased overflow pressure, dehydration, and calcium loss

ANS: C Circuit-related complications of continuous renal replacement therapy include air embolism, clotted hemofilter, poor ultrafiltration, blood leaks, broken filter, disconnection, access failure, and catheter dislodgement

A patient was admitted with liver failure and acute kidney injury (AKI). Which intravenous solution should the nurse question if it were ordered for this patient? a. D5W b. 0.9% NaCl c. Lactated Ringer solution d. 0.45% NaCl

ANS: C Lactated Ringer solution is contraindicated for patients with kidney or liver diseases or in lactic acidosis.

One therapeutic measure for treating hyperkalemia is the administration of dextrose and regular insulin. Which statement regarding how this treatment works is accurate? a. Glucose and insulin force potassium out of the cells, lowering it on a cellular level. b. Glucose and insulin promote higher excretion of potassium in the urine. c. Glucose and insulin bind with potassium, lowering available amounts. d. Glucose and insulin force potassium into the cells, lowering it on a serum level.

ANS: D Acute hyperkalemia can be treated temporarily by intravenous administration of insulin and glucose. An infusion of 50 mL of 50% dextrose accompanied by 10 units of regular insulin forces potassium out of the serum and into the cells.

A patient with acute kidney injury (AKI) has been started on continuous venovenous hemodialysis (CVVHD). The nurse understands that this type of continuous renal replacement therapy (CRRT) is indicated for the patient who needs what type of treatment? a. Fluid removal only b. Fluid removal and moderate solute removal c. Fluid removal and maximum solute removal d. Maximum fluid and solute removal

ANS: D Continuous venovenous hemodialysis (CVVHD) is indicated for patients who require large-volume removal of fluid and solutes.

Which diuretics maybe combined to work on different parts of the nephron? a. Loop and thiazide diuretics b. Loop and osmotic diuretics c. Osmotic and carbonic anhydrase inhibitor diuretics d. Thiazide and osmotic diuretics

ANS: A A thiazide diuretic such as chlorothiazide (Diuril) or metolazone (Zaroxolyn) may be administered and followed by a loop diuretic to take advantage of the fact that these medications work on different parts of the nephron. Sometimes a thiazide diuretic is added to a loop diuretic to compensate for the development of loop diuretic resistance.

A patient with acute kidney injury has a potassium level of 6.9 mg/dL. The patient has had no urine output in the past 4 hours despite administration of Lasix 40 mg intravenous push. To correct the hyperkalemia the patient is given 50 mL of 50% dextrose in water and 10 U of regular insulin intravenous push. A repeat potassium level 2 hours later shows a potassium level of 4.5 mg/dL. What order would the nurse expect now? a. Sodium Kayexalate 15 g PO b. Nothing; this represents a normal potassium level c. Lasix 40 mg IVP d. 0.9% normal saline at 125 mL/h

ANS: A Acute hyperkalemia can be treated temporarily by intravenous (IV) administration of insulin and glucose. An infusion of 50 mL of 50% dextrose accompanied by 10 units of regular insulin forces potassium out of the serum and into the cells. However, the potassium was not eliminated from the body; it was simply shifted intracellularly. Soon the potassium will return to the bloodstream, and the Kayexalate will help permanently remove it from the body. Lasix is not expected to work in the presence of anuria. The patient's vital signs do not support hypovolemia. In the presence of anuria, a large fluid infusion can precipitate acute heart failure.

The practitioner has ordered dialysis for a patient with acute heart failure who is unresponsive to diuretics. Which type of dialysis would the nurse anticipate being started on this patient? a. Intermittent ultrafiltration b. Continuous venovenous hemofiltration (CVVH) c. Continuous venovenous hemodialysis (CVVHD) d. Continuous venovenous hemodiafiltration (CVVHDF)

ANS: A Intermittent ultrafiltration using a peripheral venous catheter is more likely to be used to remove excess volume from patients with acute decompensated heart failure when the kidneys are unresponsive to diuretics.

A patient is admitted with acute kidney injury (AKI). Which event from the patient's history was the most probable cause of the patient's AKI? a. Recent computed tomography of the brain with and without contrast b. Recent bout of acute heart failure after an acute myocardial infarction c. Twice-daily prescription of Lasix 40 mg by mouth d. Recent bout of benign prostatic hypertrophy and transurethral resection of the prostate

ANS: A Intravenous contrast media can be nephrotoxic, especially with the patient's preexisting cardiac disease. The other choices, although possible causes, are less likely than the intravenous contrast media.

A patient who receives peritoneal dialysis is admitted after a 3-day history of flulike symptoms. The patient reports muscle cramps and is noted to have a low blood pressure and tachycardia. The nurse suspects the patient may be experiencing what condition? a. Dehydration b. Peritonitis c. Fluid obstruction d. Hernias

ANS: A This patient has dehydration. This patient is showing signs and symptoms of muscle cramps and low blood pressure.

A patient was admitted with an infection that had to be treated with an aminoglycoside antibiotic. After a few days the patient developed oliguria and elevated blood urea nitrogen and creatinine levels. The patient's vital signs are stable. The nurse would anticipate the practitioner ordering which dialysis method for this patient? a. Peritoneal dialysis b. Hemodialysis c. Continuous renal replacement therapy d. Intermittent ultrafiltration

ANS: B As a treatment, hemodialysis separates and removes from the blood excess electrolytes, fluids, and toxins by means of a hemodialyzer. Hemodialysis would be the first choice for managing this patient with medication toxicity.

A patient with chronic kidney disease was admitted with severe electrolyte disturbances. The patient had been ill and missed several hemodialysis sessions. The patient is disoriented, dizzy, cold, clammy, and complains of severe abdominal cramping. The patient's electrocardiogram appears normal. Which electrolyte disturbance would the nurse suspect the patient may be experiencing? a. Hyponatremia b. Hypokalemia c. Hypercalcemia d. Hypochloremia

ANS: B Hyperkalemia, hypocalcemia, hyponatremia, hyperphosphatemia, and acid-base imbalances occur in kidney disease. Signs of hyponatremia include disorientation, muscle twitching, nausea, vomiting, abdominal cramps, headaches, dizziness, cold, clammy skin, tachycardia, and seizures.

Which medication is classified as a loop diuretic? a. Acetazolamide b. Furosemide c. Mannitol d. Metolazone

ANS: B Loop diuretics include furosemide, bumetanide, and torsemide. Furosemide is the most frequently used diuretic in critical care patients. It may be administered orally, as an intravenous (IV) bolus, or as a continuous IV infusion. Diamox is a carbonic anhydrase inhibitor diuretic. Mannitol is an osmotic diuretic, and metolazone is a thiazide diuretic.

A patient has developed acute kidney injury (AKI) secondary to hemorrhage shock. Which intravenous solution would the nurse expect to be ordered for this patient? a. Dextrose in water b. Normal saline c. Albumin d. Lactated Ringer solution

ANS: B Prerenal acute kidney injury (AKI) is caused by decreased perfusion and flow to the kidney. It is often associated with trauma, hemorrhage, hypotension, and major fluid losses. If contrast dye is used, aggressive fluid resuscitation with normal saline is recommended.

A patient has developed acute kidney injury (AKI) secondary to cardiogenic shock. Which laboratory value would the nurse find helpful in evaluating patient's renal status? a. Serum sodium b. Serum creatinine c. Serum potassium d. Urine potassium

ANS: B Serum creatinine is the most reliable predictor of kidney function. In the acutely ill patient, small changes in the serum creatinine level and urine output may signal important declines in the glomerular filtration rate and kidney function.

What is the most common site for short-term vascular access for immediate hemodialysis? a. Subclavian artery b. Subclavian vein c. Femoral artery d. Radial vein

ANS: B Subclavian and femoral veins are catheterized when short-term access is required or when a graft or fistula vascular access is nonfunctional in a patient requiring immediate hemodialysis. Subclavian and femoral catheters are routinely inserted at the bedside. Most temporary catheters are venous lines only. Blood flows out toward the dialyzer and flows back to the patient through the same catheterized vein. A dual-lumen venous catheter is most commonly used.

An alert and oriented patient presents with a pulmonary artery occlusion pressure (PAOP) of 4 mm Hg, blood pressure of 88/50 mm Hg, cardiac index of 1.8, and urine output of 15 mL/h. The patient's blood urea nitrogen (BUN) is 44 mg/dL and creatinine is 3.2 mg/dL. Lungs are clear to auscultation with no peripheral edema noted. Which treatment would the nurse expect the practitioner to order? a. Lasix 40 mg intravenous push b. 0.9% normal saline at 125 mL/h c. Dopamine 15 mcg/kg/min d. Transfuse 1 U of packed red blood cells

ANS: B The patient's hemodynamic parameters are most consistent with hypovolemia. The acute kidney injury would probably be prerenal from inadequate blood flow. The treatment of choice for hypovolemia is fluid resuscitation. Important criteria when calculating fluid volume replacement include baseline metabolism, environmental temperature, and humidity. The rate of replacement depends on cardiopulmonary reserve, adequacy of kidney function, urine output, fluid balance, ongoing loss, and type of fluid replaced.

What is the recommended nutritional intake of protein to control azotemia in the patient with acute kidney injury? a. 0.5 to 1.0 g/kg/day b. 1.2 to 1.5 g/kg/day c. 1.7 to 2.5 g/kg/day d. 2.5 to 3.5 g/kg/day

ANS: B The recommended energy intake is between 20 and 30 kcal/kg/day, with 1.2 to 1.5 g/kg of protein per day to control azotemia (increased blood urea nitrogen level).

An elderly patient is in a motor vehicle accident and sustains a significant internal hemorrhage. The nurse knows the patient is at risk for developing what type of acute kidney injury (AKI)? a. Intrinsic b. Postrenal c. Prerenal d. Intrarenal

ANS: C Any condition that decreases blood flow, blood pressure, or kidney perfusion before arterial blood reaches the renal artery that supplies the kidney may be anatomically described as prerenal acute kidney injury (AKI). When arterial hypoperfusion caused by low cardiac output, hemorrhage, vasodilation, thrombosis, or other cause reduces the blood flow to the kidney, glomerular filtration decreases, and consequently urine output decreases. Any condition that produces an ischemic or toxic insult directly at parenchymal nephron tissue places the patient at risk for development of intrarenal AKI. Any obstruction that hinders the flow of urine from beyond the kidney through the remainder of the urinary tract may lead to postrenal AKI.

A patient with chronic kidney disease receives hemodialysis treatments 3 days a week. Every 2 weeks, the patient requires a transfusion of 1 or 2 U of packed red blood cells. What is the probable reason for this patient's frequent transfusion needs? a. Too much blood phlebotomized for tests b. Increased destruction of red blood cells because of the increased toxin levels c. Lack of production of erythropoietin to stimulate red blood cell formation d. Hemodilution secondary to fluid retention

ANS: C In chronic kidney disease, the kidneys do not produce sufficient amounts of erythropoietin in response to normal stimuli such as anemia or hypotension. The other choices are not reasons for frequent blood transfusions in this patient.

What is the dose for low-dose dopamine? a. 1 to 2 mcg/kg/min b. 1 to 2 mg/kg/min c. 2 to 3 mcg/kg/min d. 2 to 3 mg/kg/min

ANS: C Low-dose dopamine (2 to 3 mcg/kg/min), previously known as renal-dose dopamine, is frequently infused to stimulate blood flow to the kidney. Dopamine is effective in increasing urine output in the short term, but tolerance of the dopamine renal receptor to the medication is theorized to develop in the critically ill patients who are most at risk for acute kidney injury.

A patient with acute kidney injury (AKI) has been started on continuous venovenous hemodialysis (CVVHD). The nurse understands the patient should be closely monitored for what patient-related complications of the therapy? a. Air embolism, access failure, and blood leaks b. Decreased inflow pressure, air bubbles, and power surge c. Infection, hypotension, and electrolyte imbalances d. Catheter dislodgement, decreased outflow pressure, and acid-base imbalances

ANS: C Patient-related complications of continuous renal replacement therapy (CRRT) include dehydration, hypotension, electrolyte imbalances, acid-base imbalances, blood loss, hemorrhage, hypotension, and infection.

To assess whether or not an arteriovenous fistula is functioning, what must the nurse do and why? a. Palpate the quality of the pulse distal to the site to determine whether a thrill is present; auscultate with a stethoscope to appreciate a bruit to assess the quality of the blood flow. b. Palpate the quality of the pulse proximal to the site to determine whether a thrill is present; auscultate with a stethoscope to appreciate a bruit to assess the quality of the blood flow. c. Palpate gently over the site of the fistula to determine whether a thrill is present; listen with a stethoscope over this site to appreciate a bruit to assess the quality of the blood flow. d. Palpate over the site of the fistula to determine whether a thrill is present; check whether the extremity is pink and warm.

ANS: C The nurse frequently assesses the quality of blood flow through the fistula. A patent fistula has a thrill when palpated gently with the fingers and a bruit when auscultated with a stethoscope. The extremity should be pink and warm to the touch. No blood pressure measurements, intravenous infusions, or laboratory phlebotomy is performed on the arm with the fistula.

A patient is admitted with sepsis and acute kidney injury (AKI). The patient is started on continuous renal replacement therapy (CRRT). The nurse knows that fluid that is removed each hour is charted as what on the CRRT flowsheet? a. Convection b. Diffusion c. Replacement fluid d. Ultrafiltrate

ANS: D The fluid that is removed each hour is not called urine; it is known as ultrafiltrate. Typically, some of the ultrafiltrate is replaced through the continuous renal replacement therapy circuit by a sterile replacement fluid. Diffusion is the movement of solutes along a concentration gradient from a high concentration to a low concentration across a semipermeable membrane. Convection occurs when a pressure gradient is set up so that the water is pushed or pumped across the dialysis filter and carries the solutes from the bloodstream with it.

Laboratory results come back on a newly admitted patient: Serum blood urea nitrogen, 64 mg/dL; serum creatinine, 2.4 mg/dL; urine osmolality, 210 mOsm/kg; specific gravity, 1.002; and urine sodium, 96 mEq/L. The patient's urine output has been 120 mL since admission 2 hours ago. These values are most consistent with which diagnosis? a. Prerenal acute kidney injury b. Postrenal acute kidney injury c. Oliguric acute kidney injury d. Intrarenal acute kidney injury

ANS: D Urinary sodium less than 10 mEq/L (low) suggests a prerenal condition. Urinary sodium greater than 40 mEq/L (in the presence of an elevated serum creatinine and the absence of a high salt load) suggests intrarenal damage has occurred. The urine output does not seem to suggest oliguria. The other options do not fit the data as presented.