MCQ 4

Q4.The most useful and predictive tool in evaluating the condition of a patient with an acute asthmatic attack and in assessing response to therapy is
  A. Chest radiography
  B. Arterial blood gas measurement
  C. Measurement of pulsus paradoxus
  D. Observation of accessory muscles use
  E.  Measurement of peak expiratory flow or FEV1

Answer and explanation

The correct answer is "E".

Explanation :

Several investigations have shown that the most efficient means of assessing the severity of an asthmatic attack and of following the therapeutic response is the measurement of some parameter of respiratory function such as peak flow or forced expiratory volume in 1 sec(FEV 1).

"The chest radiograph will frequently show only hyperinflation in attacks of varying degrees of severity.

Arterial blood gas will reflect hypoxemia and and hypercapnia in all but the most severe episodes, when they may reflect respiratory fatigue and severe obstruction as rising Pco2 levels .

Accessory muscles use and the presence of pulsus paradoxus reflect changes in intrathoracic pressure and the work of breathing, and they may actually disappear if the patient's breathing worsens to the point of becoming shallow. Thus, these signs may be misleading".