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 D
Explanation
Order a high-fiber diet
Choice A Reason:
Encourage dietary intake
Encouraging dietary intake is generally important for maintaining nutritional status, but it is not specific to the preparation for a barium enema. The preparation for a barium enema typically involves dietary restrictions to ensure the colon is clear for the procedure. Therefore, this choice is not correct.
Choice B Reason:
Encourage plenty of fat
Encouraging plenty of fat is not appropriate for the preparation of a barium enema. High-fat foods can slow down the digestive process and may interfere with the clarity of the images obtained during the procedure. Therefore, this choice is not correct.
Choice C Reason:
Serve dairy products
Serving dairy products is not recommended before a barium enema. Dairy products can cause gas and bloating, which can interfere with the procedure. Additionally, some patients may be lactose intolerant, which can further complicate the preparation. Therefore, this choice is not correct.
Choice D Reason:
Order a high-fiber diet
Ordering a high-fiber diet is the correct choice. A high-fiber diet helps to clear the intestines by promoting bowel movements. This is important for ensuring that the colon is empty and clear for the barium enema, which allows for better imaging and more accurate results.
Correct Answer is D
Explanation
Choice A: Rosebud-like Stoma Orifice
A rosebud-like stoma orifice is typically a normal appearance for a new stoma. The stoma should be moist, pink to red in color, and protrude slightly from the abdomen, resembling a rosebud. This appearance indicates good blood flow and proper healing. Therefore, this finding does not usually require immediate reporting to the provider.
Choice B: Stoma Oozing Red Drainage
While some minor bleeding or oozing can be normal immediately after surgery, persistent or significant red drainage from the stoma could indicate a complication such as infection or trauma to the stoma site. This finding should be monitored closely, but it is not as immediately concerning as a purplish-colored stoma, which indicates a more severe issue.
Choice C: Shiny, Moist Stoma
A shiny, moist stoma is a sign of a healthy stoma. The stoma should always appear moist and slightly shiny due to the mucus produced by the intestinal lining. This finding is normal and does not require reporting to the provider.
Choice D: Purplish-Colored Stoma
A purplish-colored stoma is an immediate concern and should be reported to the provider. This discoloration can indicate compromised blood flow to the stoma, which can lead to tissue necrosis if not addressed promptly. Ensuring adequate blood supply is crucial for the stoma’s viability and the patient’s overall health. Immediate medical intervention is necessary to prevent further complications.
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