On arrival at the intensive care unit, a critically ill patient suffers respiratory arrest and is placed on mechanical ventilation. The physician orders pulse oximetry to monitor the patient’s arterial oxygen saturation (SaO₂) noninvasively. Which vital sign abnormality may alter pulse oximetry values?
Tachycardia
Hypotension
Tachypnea
Fever
The Correct Answer is B
Choice A: Tachycardia
Tachycardia, defined as a heart rate exceeding 100 beats per minute, can affect the accuracy of pulse oximetry readings. When the heart beats too quickly, it may not fill with enough blood between beats, leading to reduced perfusion and oxygen delivery to tissues. However, while tachycardia can influence the readings, it is not the most significant factor compared to hypotension.
Choice B: Hypotension
Hypotension, or low blood pressure, significantly impacts pulse oximetry accuracy. When blood pressure is low, there is reduced perfusion to peripheral tissues, including the extremities where pulse oximeters are typically placed. This reduced perfusion can lead to inaccurate readings, as the device may not detect sufficient blood flow to measure oxygen saturation accurately. Hypotension is a critical factor that can alter pulse oximetry values, making it the most relevant choice.
Choice C: Tachypnea
Tachypnea, or rapid breathing, can affect oxygen levels in the blood but does not directly interfere with the pulse oximeter’s ability to measure oxygen saturation. While it indicates respiratory distress and can lead to hypoxemia, the pulse oximeter can still provide accurate readings unless accompanied by other factors like low perfusion.
Choice D: Fever
Fever can cause peripheral vasodilation, which might theoretically affect pulse oximetry readings by altering blood flow to the extremities. However, this effect is generally minimal compared to the impact of hypotension. Fever alone is unlikely to cause significant inaccuracies in pulse oximetry measurements.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A Reason:
Constant bubbling in the water seal chamber of a chest drainage system typically indicates an air leak. This can occur if there is a break in the system, allowing air to enter. The air leak could be from the chest tube insertion site, the tubing, or the drainage system itself. Identifying and correcting the source of the air leak is crucial to ensure the system functions properly and the patient’s condition does not worsen.
Choice B Reason:
A tension pneumothorax is a life-threatening condition where air accumulates in the pleural space and cannot escape, leading to increased pressure on the lungs and other thoracic structures. While a tension pneumothorax can cause significant respiratory distress, it is not typically indicated by constant bubbling in the water seal chamber. Instead, signs of tension pneumothorax include tracheal deviation, hypotension, and severe respiratory distress.
Choice C Reason:
A kink in the tubing of a chest drainage system can obstruct the flow of air and fluid, but it does not cause constant bubbling in the water seal chamber. Instead, a kink would likely result in a lack of drainage or intermittent bubbling as the obstruction temporarily blocks and then allows passage of air or fluid.
Choice D Reason:
Increased drainage in a chest tube system indicates that more fluid or air is being removed from the pleural space, but it does not cause constant bubbling in the water seal chamber. Increased drainage might be seen in cases of hemothorax or pleural effusion, where large amounts of fluid are present.
Choice E Reason:
Tidaling refers to the normal rise and fall of water in the water seal chamber with the patient’s respiratory cycle. It indicates that the chest tube is patent and functioning correctly. Absence of tidaling could suggest that the lung has fully re-expanded or that there is an obstruction in the system. However, tidaling itself does not cause constant bubbling.
Correct Answer is ["A","B","C","D"]
Explanation
Choice A reason: A buffalo hump is a characteristic sign of Cushing’s syndrome. It refers to the accumulation of fat on the back of the neck and shoulders. This symptom occurs due to the excessive production of cortisol, which leads to abnormal fat distribution in the body.
Choice B reason: Moon face is another hallmark of Cushing’s syndrome. It describes the rounding and fullness of the face, which results from fat deposits. This symptom is also caused by prolonged exposure to high levels of cortisol.
Choice C reason: Hypertension, or high blood pressure, is commonly associated with Cushing’s syndrome. Cortisol increases blood pressure by enhancing the sensitivity of blood vessels to catecholamines and by promoting sodium and water retention.
Choice D reason: Purple striations, or stretch marks, are often seen in individuals with Cushing’s syndrome. These marks typically appear on the abdomen, thighs, breasts, and arms. They result from the thinning of the skin and the breakdown of collagen due to elevated cortisol levels.
Choice E reason: Tremors are not typically associated with Cushing’s syndrome. While Cushing’s syndrome can cause a variety of symptoms, tremors are more commonly linked to other conditions such as hyperthyroidism or neurological disorders.
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