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  #1  
Old 07-22-2012
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Lungs Asthma - the best clinical indicator of obstruction

Which of the following is the best clinical indicator of significant pulmonary obstruction in patients with asthma?

A) Arterial hypoxemia
B) Dyspnea
C) FEV1/FVC ratio of less than 75%
D) Large anatomic dead space volume
E) Rapid respirations
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Old 07-22-2012
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I initially thought B or C.. But will go with A

But significant obstruction ll lead to Arte Hypoxemia.. As in status asthmaticus..
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Old 07-22-2012
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CLINICAL indicator would be A i guess
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You specifically asked for CLINICAL findings, so I'll say its E. greater the work needed for breathing, greater the rate of respiration. As the obstruction worsens, the patient takes shallow and rapid breaths.

Dyspnea is subjective so pretty much useless. Arterial hypoxemia isnt a clinical finding...even if you have a pulse oxymeter in your pocket
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Old 07-22-2012
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Quote:
Originally Posted by smanthrav View Post
You specifically asked for CLINICAL findings, so I'll say its E. greater the work needed for breathing, greater the rate of respiration. As the obstruction worsens, the patient takes shallow and rapid breaths.

Dyspnea is subjective so pretty much useless. Arterial hypoxemia isnt a clinical finding...even if you have a pulse oxymeter in your pocket
What abt silent chest - tachypnea cant be seen in this, but its an emergency.

Arterial hypoxia decides the amt of obstruction and need for mechanical ventilation.
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Originally Posted by curiousmind View Post
What abt silent chest - tachypnea cant be seen in this, but its an emergency.

Arterial hypoxia decides the amt of obstruction and need for mechanical ventilation.
I agree. I'm just not sure if you can call arterial PO2 a clinical indicator.
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Old 07-22-2012
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E)...???
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Clinical indicator is probably B.
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Old 07-23-2012
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Default correct answer :)

I went for arterial hypoxemia, I figured that dyspnea would be too subjective. For some reason this question makes all of us think about the exacerbation of asthma while the question never mentions anything like that (subliminal manipulation? ).

The way I think about thi squestion now, knowing the answer, is that they asked the clinical indicator of significant pulmonary obstruction meaning the severity of asthma (stages), so spirometry parameters are the only ones among the given options that actually fit.


Here's an official (really long!) explanation.

Option C (FEV1/FVC ratio of less than 75%) is correct. In individuals with chronic obstructive pulmonary diseases (COPD), including asthma, resistance to airflow is increased, which makes it much more difficult to breathe. This difficulty is due to a reduction in the diameter of the airways of the lungs. The most sensitive measure of airway obstruction is the FEV1/FVC ratio, where FEV1 is the amount of air that can be exhaled forcefully within 1 second, and FVC (forced vital capacity) is the total amount of air exhaled through a maximal forceful expiration. Airway obstruction is indicated when the FEV1/FVC ratio falls below 75%.

Option A (Arterial hypoxemia) is incorrect. In individuals with severe airway obstruction, arterial blood can become significantly hypoxemic. However, hypoxemia is not specific to the diagnosis of pulmonary obstruction.

Option B (Dyspnea) is incorrect. Dyspnea is not specific to the diagnosis of pulmonary obstruction. Patients who complain about breathing limitations during exercise or even at rest should be given a pulmonary function test. Normal individuals should be capable of expelling 8085% of their vital capacity within 1 second.

Option D (Large anatomic dead space volume) is incorrect. The amount of anatomic dead space (locations where air is not exchanged) does not change even during a severe asthmatic attack.

Option E (Rapid respirations) is incorrect. In individuals with asthma, constricted airways prohibit rapid expulsion of air. Thus, the respiratory rate in asthmatics tends to be slower than normal.
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Old 07-23-2012
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Default Just random

Hi Casandra! I was just wondering where you get all these good questions from? Is it from uworld or any other qbank? Just wondering, because if its from a diff source than uworld, i would go through them all, otherwise there's so many! Lol
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