A nurse is caring for a patient who has acute kidney injury.
The patient’s ABGs are: pH: 7.26, PaCO2: 30 mm Hg, HCO3: 14 mEq/L. Which of the following acid-base imbalances should the nurse identify the patient is experiencing?
Metabolic alkalosis.
Metabolic acidosis.
Respiratory alkalosis.
Respiratory acidosis.
The Correct Answer is B
Choice A rationale:
Metabolic alkalosis is characterized by a high pH (above 7.45), high bicarbonate (HCO3-) levels, and normal or low PaCO2. The patient's ABGs show a low pH (7.26), low bicarbonate (14 mEq/L), and low PaCO2 (30 mm Hg), which are not consistent with metabolic alkalosis.
Choice C rationale:
Respiratory alkalosis is characterized by a high pH (above 7.45), low PaCO2, and normal or slightly elevated bicarbonate levels. The patient's ABGs do show a low PaCO2, but the pH is low (acidic) and the bicarbonate is low, which are not consistent with respiratory alkalosis.
Choice D rationale:
Respiratory acidosis is characterized by a low pH (below 7.35), high PaCO2, and normal or slightly elevated bicarbonate levels. The patient's ABGs do show a low pH, but the PaCO2 is also low, which is not consistent with respiratory acidosis.
Rationale for the correct answer, B:
Metabolic acidosis is characterized by a low pH (below 7.35), low bicarbonate levels, and normal or low PaCO2. The patient's ABGs are consistent with metabolic acidosis because they show a low pH (7.26), low bicarbonate (14 mEq/L), and low PaCO2 (30 mm Hg).
Acute kidney injury is a common cause of metabolic acidosis. The kidneys play a vital role in regulating acid-base balance by excreting acids and reabsorbing bicarbonate. When the kidneys are damaged, they are unable to excrete acids effectively, leading to an accumulation of acids in the blood and a decrease in bicarbonate levels.
Additional Information:
It's important to note that the patient's low PaCO2 is likely a compensatory mechanism for the metabolic acidosis. In response to acidosis, the respiratory system tries to increase ventilation to blow off more carbon dioxide, which helps to raise the pH. However, this compensatory mechanism is often not enough to fully correct the acidosis.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A rationale:
Distended neck veins are not a reliable indicator of dehydration in adults. They can be caused by other factors, such as heart failure or fluid overload.
In cases of dehydration, the veins in the neck may actually be less visible due to decreased blood volume.
It's important to assess for other signs and symptoms of dehydration, such as urine output, skin turgor, and vital signs, to make an accurate diagnosis.
Choice B rationale:
A bounding pulse can be a sign of dehydration, but it can also be caused by other factors, such as anxiety, exercise, or fever. It's important to assess the pulse rate and rhythm in conjunction with other signs and symptoms to determine the cause.
A normal pulse rate is 60-100 beats per minute in adults. A bounding pulse is typically a strong, forceful pulse that can be easily felt.
Choice C rationale:
A blood pressure of 146/94 mm Hg is considered elevated, but it is not necessarily a sign of dehydration. Blood pressure can be elevated due to other factors, such as stress, pain, or underlying medical conditions. It's important to assess blood pressure in conjunction with other signs and symptoms to determine the cause. Choice D rationale:
Urine specific gravity is a measure of the concentration of solutes in the urine. A higher urine specific gravity indicates more concentrated urine, which is a sign of dehydration.
A normal urine specific gravity is 1.005-1.030. A urine specific gravity of 1.034 is considered high and is a strong indicator of dehydration.
Correct Answer is B
Explanation
Choice A rationale:
The spinal cord plays a crucial role in pain transmission, but it does not initiate the afferent pathways. It receives pain signals from nociceptors and relays them to the brain for processing.
The spinal cord is also involved in pain modulation, as it can dampen or amplify pain signals depending on various factors. However, it is not the primary trigger for pain sensation. That role belongs to nociceptors.
Choice B rationale:
Nociceptors are specialized sensory receptors that detect potentially damaging stimuli, such as intense heat, pressure, or chemical irritants.
They are located throughout the body, including the skin, muscles, joints, and internal organs.
When nociceptors are activated, they generate electrical signals that travel along nerve fibers to the spinal cord and brain. This process initiates the afferent pathways, which ultimately lead to the conscious perception of pain.
Nociceptors are essential for protecting the body from harm. They alert us to potential dangers and trigger responses that help us avoid injury or further damage.
Choice C rationale:
Endorphins are natural pain-relieving substances produced by the body. They act on receptors in the brain and spinal cord to reduce pain perception.
However, endorphins do not trigger the afferent pathways. They work by modulating pain signals that have already been initiated by nociceptors.
Choice D rationale:
The cortex is the outer layer of the brain that is responsible for higher-level functions, such as thinking, feeling, and decision- making.
It plays a role in the conscious experience of pain, but it does not trigger the afferent pathways.
The cortex receives pain signals from the spinal cord and processes them, leading to the awareness of pain.
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