A premature infant has two pulse oximeters placed: one on the ...

[future617RT]

A premature infant has two pulse oximeters placed: one on the right hand and one on the left foot. The respiratory therapist notes that the reading on the right hand is consistently 12 greater than the reading on the left foot.
 
  Which of the following is the best interpretation of this finding?
  a. The infant has left-sided intra-pulmonary shunting.
  b. The infant likely has pneumonia.
  c. The infant is in septic shock with systemic capillary shunting.
  d. The infant has persistent pulmonary hypertension of the newborn.
  e. The infant has shunting across the ductus venosus.

Question 2

A patient had a penetrating knife wound to her chest wall that resulted in a valvular pneumothorax. What is another term for this condition?
 
  a. Spontaneous pneumothorax
  b. Tension pneumothorax
  c. Iatrogenic pneumothorax
  d. Benign pneumothorax

[katara]

Answer to Question 1

D
For the newborn in respiratory distress, pulse oximetry is often used to monitor both the preductal SpO2 and the postductal SpO2 . To measure the preductal SpO2, the oximeter probe is placed on the right hand or wrist; to measure the postductal SpO2, the probe is placed on either foot. A large difference between the two readings (>10) indicates a right-to-left shunt, and persistent pulmonary hypertension of the newborn (PPHN) is likely.

Answer to Question 2

B
A valvular pneumothorax is also called a tension pneumothorax. Gas enters the pleural space on inspiration but cannot exit due to the valvelike action of the pleura or chest wall itself.