Examination questions.
20 October 2003



A seven year old boy of Samoan descent is seen at at a doctor's office. 
There are no abnormal sounds on chest examination, but his mother says 
he has been wheezing. Your initial thinking is that...

      a) there is no evidence of airway obstruction, so asthma is unlikely
      b) his mother's account of the case is likely to be misleading
      c) a flow-volume curve should be obtained using a pneumotachograph
      d) the noise his mother describes is likely have been due to 
      turbulent air flow during inspiration 
->    e)  the length and time-course of the history are most likely to be 
      helpful in diagnosis 




Measurement of percentage saturation of hemoglobin by oxygen, "Sa02",

      a) is done on an arterial blood gas machine in a clinical laboratory
->    b) may give normal results in patients suffering severe dyspnea
      c) is low in anemia, because of the reduced oxygen content of the blood
      d) requires that an arterial blood gas sample be drawn
      e) gives a value directly proportional to the amount of oxygen in the blood



"Central" cyanosis

      a) indicates there is more than a certain amount of carboxyhemoglobin in the blood
      b) is detected as a green colour often seen best in the lips
      c) is an objective and reliable indicator of arterial deoxygenation
->    d) is better seen in a polycythemic than in an anemic individual
      e) may be due to pooling of blood in the limbs in cold weather