ATI Fluid and Electrolyte Exam

Correct answer C: respiratory alkalosis with compensation

Explanation:

C. respiratory alkalosis with compensation

In this case, the patient's pH is 7.52, which is alkalotic (normal pH range: 7.35–7.45). The decreased PaCO2 and HCO3- levels indicate that the body is compensating for respiratory alkalosis. Typically, in respiratory alkalosis, there is a decrease in PaCO2 due to hyperventilation, and the kidneys try to compensate by decreasing bicarbonate (HCO3-) to buffer the pH change. Thus, the decreased bicarbonate suggests that the kidneys are compensating for the alkalosis caused by the respiratory system.

Why the other options are incorrect:

A. respiratory acidosis without compensation

Respiratory acidosis occurs when the PaCO2 increases, typically due to hypoventilation or respiratory depression. In this case, the PaCO2 is decreased, so this option is not consistent with the ABG results.

B. metabolic acidosis with compensation

Metabolic acidosis would typically show decreased bicarbonate (HCO3-) levels and a compensatory decreased PaCO2 as the body attempts to balance the pH. However, the pH is alkalotic (7.52), not acidotic, so this is not consistent with the patient's results.

D. metabolic alkalosis without compensation

Metabolic alkalosis would result in an elevated pH and an increase in bicarbonate (HCO3-). The decreased bicarbonate seen here, coupled with a high pH, is not indicative of metabolic alkalosis. Furthermore, the decreased PaCO2 suggests compensation, not a lack of compensation.

Summary:

The patient is experiencing respiratory alkalosis with compensation, as evidenced by the elevated pH, decreased PaCO2, and decreased bicarbonate (HCO3-) levels, indicating renal compensation for the respiratory alkalosis.

The correct answers are B: pH 7.29 and C. PaCO2 49 mm Hg.

Explanation of the correct answers:

B. pH 7.29

Metabolic acidosis is characterized by a low pH, typically less than 7.35. A pH of 7.29 indicates that the client is in acidosis, which is consistent with metabolic acidosis. In this condition, the kidneys are unable to excrete enough acid, leading to a decrease in blood pH.

C. PaCO2 49 mm Hg

In metabolic acidosis, the body compensates by increasing respiratory rate to expel CO2, which is an acid. However, compensation may not be fully effective, and PaCO2 can remain elevated as the body tries to buffer the excess acid. A PaCO2 level of 49 mm Hg suggests respiratory compensation for the metabolic acidosis, though it is still higher than the normal range of 35-45 mm Hg.

Why the other options are incorrect:

A. HCO3- 29 mEq/L

In metabolic acidosis, the bicarbonate (HCO3-) level is typically low (below 22 mEq/L) due to the loss of bicarbonate or accumulation of acids. A level of 29 mEq/L is elevated, which would indicate metabolic alkalosis, not acidosis.

D. pH 7.49

A pH of 7.49 is alkaline, not acidic. This value would be consistent with metabolic alkalosis rather than metabolic acidosis. A normal pH range is 7.35-7.45, and a value above 7.45 suggests alkalosis.

E. PaCO2 30 mm Hg

A PaCO2 of 30 mm Hg is lower than the normal range, indicating respiratory compensation for alkalosis. In metabolic acidosis, the body would typically attempt to decrease CO2 levels through hyperventilation to lower the acid load. However, the PaCO2 would typically be higher or normal, not lower in metabolic acidosis.

Summary:

In metabolic acidosis, the nurse should expect a low pH (indicating acidosis), and PaCO2 may be elevated due to respiratory compensation. The HCO3- is typically low in metabolic acidosis, and a pH of 7.49 would suggest alkalosis, not acidosis. Thus, the correct answers are pH 7.29 and PaCO2 49 mm Hg.

The correct answer is D: Compensated metabolic acidosis.

Explanation of the correct answer:

D. Compensated metabolic acidosis

In a patient with emphysema, the primary issue is often respiratory acidosis, caused by impaired gas exchange and the inability to expel CO2 properly. This leads to an accumulation of CO2, which increases the concentration of carbonic acid in the blood and lowers the pH (making the blood more acidic). The kidneys typically compensate for respiratory acidosis by retaining bicarbonate ions (HCO3-) in an effort to buffer the excess acid and increase the blood pH.

However, in this case, the kidneys have retained more bicarbonate, but not enough to correct the pH problem. The patient has compensated to some extent (as indicated by the retention of bicarbonate), but not enough to fully normalize the pH. Therefore, this situation is considered compensated metabolic acidosis — the kidneys are trying to balance the acidosis caused by respiratory issues, but the compensation is incomplete.

Why the other options are incorrect:

A. Uncompensated metabolic alkalosis

Metabolic alkalosis is characterized by an increase in blood pH due to an excess of bicarbonate or loss of hydrogen ions. In this case, the patient is retaining bicarbonate, but it is not enough to correct the acidosis, so the condition is not metabolic alkalosis, nor is it uncompensated. Uncompensated metabolic alkalosis would involve an increase in blood pH, not a decrease.

B. Uncompensated respiratory alkalosis

Respiratory alkalosis occurs when there is excessive loss of CO2 (often due to hyperventilation), which leads to a decrease in carbonic acid and an increase in pH. In this patient's case, emphysema is typically associated with respiratory acidosis, not alkalosis, and the kidneys are compensating for the acidosis by retaining bicarbonate. Therefore, this option does not match the situation.

C. Compensated respiratory acidosis

Compensated respiratory acidosis involves a condition where the lungs are unable to expel CO2 efficiently, leading to increased blood CO2 levels and acidosis. The kidneys attempt to compensate by retaining bicarbonate to neutralize the acid. While this patient does have respiratory acidosis from emphysema, the compensation described involves the kidneys retaining bicarbonate, making it a metabolic compensation. The acidosis is respiratory, but the compensation is metabolic, leading to compensated metabolic acidosis rather than compensated respiratory acidosis.

Summary:

The patient's emphysema has caused respiratory acidosis, and while the kidneys are attempting to compensate by retaining bicarbonate, they have not done so enough to correct the blood pH. This is consistent with compensated metabolic acidosis, as the kidneys are working to buffer the acidosis but have not fully resolved it.

The correct answer is C: When I sit down to watch television, I'll be sure to put my feet up.

Explanation of the correct answer:

C. When I sit down to watch television, I'll be sure to put my feet up.

This statement reflects a correct understanding of how to manage venous insufficiency, which occurs when the veins in the lower extremities cannot adequately return blood to the heart. Elevating the legs improves venous return, reduces venous pressure, and helps to decrease swelling and prevent venous stasis ulcers. Clients with venous insufficiency are encouraged to elevate their legs above the level of the heart several times per day, particularly when sitting or resting, to promote circulation and reduce edema.

Why the other options are incorrect:

A. If my stockings feel tight, I'll just roll them down for a while.

This is incorrect and potentially harmful. Compression stockings should never be rolled down, as this can cause a tourniquet effect, further impeding blood flow and worsening venous congestion. If the stockings feel too tight, the client should speak with a healthcare provider to ensure they are the correct size or pressure level.

B. I'll put on my elastic stockings at the first sign of swelling.

This reflects incorrect timing for wearing compression stockings. The client should apply compression stockings in the morning before getting out of bed, when swelling is minimal, and wear them throughout the day. Waiting until swelling occurs defeats the purpose of preventing venous pooling and edema.

D. It's okay to cross my legs as long as it's for less than an hour.

This is incorrect. Clients with venous insufficiency should be taught to avoid crossing their legs at any time, regardless of the duration, because it can impede venous return and contribute to stasis, increasing the risk of complications such as varicose veins, venous ulcers, or thrombosis.

Summary:

The most appropriate statement is C, as elevating the legs while sitting helps manage venous insufficiency by promoting venous return and reducing swelling. The other statements reflect incorrect or unsafe practices that may worsen the client’s condition.

The correct answer is D: removing excess H⁺ from the plasma

Explanation of the correct answer:

D. removing excess H⁺ from the plasma

When hydrogen ion (H⁺) concentration increases in the blood, the blood becomes more acidic. Bicarbonate ions (HCO₃⁻) act as chemical buffers by binding to free H⁺ ions, forming carbonic acid (H₂CO₃). This weak acid then quickly converts into CO₂ and water, which can be exhaled by the lungs. This process effectively removes excess H⁺ from the plasma, helping to maintain the blood's pH within the normal range (7.35–7.45).

The reaction is:

H⁺ + HCO₃⁻ → H₂CO₃ → CO₂ + H₂O

Why the other options are incorrect:

A. combining with Cl⁻

Bicarbonate does not combine with chloride to buffer hydrogen ions. However, chloride shift occurs in red blood cells for charge balance, but it’s not a direct buffering action.

B. dissociating into H⁺ and CO₃²⁻

Bicarbonate does not dissociate into H⁺ and carbonate under normal physiological conditions. That would increase acidity, not buffer it.

C. releasing H⁺ into the plasma

This would increase the acidity of the blood, which is opposite of what buffers like bicarbonate are meant to do.

E. combining with hemoglobin

Hemoglobin does buffer some H⁺ ions, but the question is specifically about bicarbonate ions, not hemoglobin.

Summary:

Bicarbonate is a key buffer in the blood, and when H⁺ increases, it helps remove those excess H⁺ ions by converting them into carbonic acid, which breaks down into CO₂ and water, thus neutralizing the acid and stabilizing pH.

The correct answer is B: The client reports that they performed yard work for 8 hr in 35° C (95° F) temperature earlier that day.

Explanation of the correct answer:

B. The client reports that they performed yard work for 8 hr in 35° C (95° F) temperature earlier that day

This is the most likely cause of a current fluid and electrolyte imbalance. Prolonged physical activity in hot temperatures increases insensible fluid losses through sweat, which contains not only water but also significant amounts of sodium, potassium, and chloride. Without adequate fluid and electrolyte replacement, this can quickly lead to dehydration, hyponatremia, or hypokalemia. The high temperature (95°F) and extended duration (8 hours) of exertion are critical risk factors that make this the most probable and immediate cause of imbalance.

Why the other options are incorrect:

A. The client reports working in a warehouse in 21.1° C (70° F) temperature

This temperature is considered moderate and unlikely to cause significant fluid loss under normal working conditions. Unless the activity was extremely strenuous, such an environment does not typically result in fluid or electrolyte imbalances. Therefore, this is not a probable cause.

C. The client reports that their provider decreased their diuretic dose

Decreasing a diuretic dose actually reduces the risk of fluid and electrolyte imbalances. Diuretics can cause losses of sodium, potassium, and water, so lowering the dose makes an imbalance less likely, not more.

D. The client reports they had a 24-hr intestinal virus 2 weeks ago

Although vomiting and diarrhea from a virus can cause electrolyte imbalances, the timing is important. Since the illness occurred 2 weeks ago and only lasted 24 hours, it is unlikely to be the current cause of the client's symptoms unless they had not fully recovered or have had ongoing symptoms, which is not indicated here.

Summary:

The most immediate and physiologically plausible cause of a fluid and electrolyte imbalance is prolonged physical exertion in hot weather, as it results in substantial fluid and electrolyte loss through sweating. The other options are either too remote in time, represent a reduced risk, or involve environments unlikely to lead to imbalance.

The correct answers are

A. A+

D. AB-

E. AB+

F. A-

Explanation of the correct answers:

A. A+

A person with A+ blood can receive A- blood. Although A+ individuals can receive Rh-positive blood, they can also safely receive Rh-negative blood (such as A-), as it will not cause an immune reaction. The ABO compatibility is also intact, as the person with A+ blood can receive A blood.

D. AB-

A person with AB- blood can receive A- blood. Since AB- individuals can receive both A and AB blood, and Rh-negative blood is compatible with their Rh factor, A- blood is suitable for them.

E. AB+

A person with AB+ blood is a universal recipient and can receive blood from any ABO group and both Rh-positive and Rh-negative blood. Therefore, A- blood can be transfused to someone with AB+ blood without issue.

F. A-

A person with A- blood can receive A- blood. Since the ABO group and Rh factor both match, there are no incompatibilities, making this a perfect match for transfusion.

Why the other options are incorrect:

B. B+

A person with B+ blood cannot receive A- blood. B+ individuals cannot tolerate A blood due to ABO incompatibility. They require B blood, not A blood.

Summary:

The following blood types can receive A- blood: A+, AB-, AB+, and A-. B+ cannot receive A- due to ABO incompatibility.

Correct answer A: Prolonged PR intervals

Explanation:

Prolonged PR intervals are typically associated with hypercalcemia. High calcium levels can alter the electrical conduction of the heart, causing a delay in the conduction through the atrioventricular (AV) node. This results in a prolonged PR interval on the electrocardiogram (ECG). Hypercalcemia can slow the conduction from the atria to the ventricles, leading to this finding.

Why the other options are incorrect:

B) Elevated ST segments:

While elevated ST segments are often linked to hypercalcemia, they are not the most common ECG change. Hypercalcemia tends to cause shortened ST segments, which could be seen as elevated ST segments in some cases. However, prolonged PR intervals are the hallmark finding for this electrolyte imbalance.

C) Prolonged QT intervals:

Prolonged QT intervals are usually seen with hypocalcemia, not hypercalcemia. In hypercalcemia, the QT interval tends to shorten due to faster repolarization.

D) Peaked T waves:

Peaked T waves are commonly seen in hyperkalemia, not hypercalcemia. Hyperkalemia affects myocardial repolarization and leads to tall, peaked T waves on the ECG.

Summary:

For a patient with hypercalcemia, a prolonged PR interval is the typical ECG finding due to delayed conduction through the AV node. This is an important finding for diagnosis and management. The elevated ST segment is a secondary effect that may be seen, but prolonged PR intervals are the most directly associated with hypercalcemia.

Correct answer A: Crohn's disease

Explanation of the correct answer:

A. Crohn's disease

Crohn's disease is a chronic inflammatory bowel disease that affects nutrient absorption in the gastrointestinal tract. Calcium is absorbed in the small intestine, and conditions like Crohn’s disease that impair the integrity or function of the intestinal lining can lead to malabsorption of calcium, increasing the risk of hypocalcemia. Inflammation, chronic diarrhea, and reduced vitamin D absorption (necessary for calcium absorption) all contribute to this risk.

Why the other options are incorrect:

B. Postoperative following appendectomy

A routine postoperative period after an appendectomy does not typically involve significant alterations in calcium levels unless there are complications such as severe infection, sepsis, or extensive gastrointestinal issues. Therefore, this is not a typical risk factor for hypocalcemia.

C. History of bone cancer

Bone cancer is more commonly associated with hypercalcemia, not hypocalcemia. This is due to bone destruction (osteolysis), which releases calcium into the bloodstream. Therefore, this condition would more likely lead to elevated serum calcium levels.

D. Hyperthyroidism

Hyperthyroidism may lead to hypercalcemia, particularly due to increased bone turnover and calcium release into the blood. Hypocalcemia is more commonly associated with hypoparathyroidism or thyroidectomy, not hyperthyroidism.

Summary:

The most appropriate and physiologically supported risk factor for hypocalcemia among the options is Crohn’s disease, due to its impact on intestinal absorption of calcium. The other options either have no significant association with hypocalcemia or are more commonly linked to hypercalcemia.