What is the Pflex on the following pressure-volume loop? a. 10 ...

[frankwu]

What is the Pflex on the following pressure-volume loop?
 
  a. 10 cm H2O
  b. 15 cm H2O
  c. 19 cm H2O
  d. 23 cm H2O

Question 2

Regardless of the procedure used to establish an appropriate PEEP level, ventilating pressures should not be allowed to exceed which of the following?
 
  a. Upper inflation point on the inspiratory limb (UIPi)
  b. 2-3 cm H2O above the UIPi
  c. 30 cm H2O
  d. Lower inflection point on the inspiratory limb

[babybsemail]

Answer to Question 1

ANS: C
The Pflex, or lower inflection point on the inspiratory limb, is the point on the curve where the slope of the inspiratory line changes significantly (see the following figure).

Answer to Question 2

ANS: A
Regardless of the procedure used to establish an appropriate PEEP level, ventilating pressures should not be allowed to exceed the UIP on the UIPi, because injury to lungs can occur if the lungs become overstretched. The appearance of the UIP on the graphic display may be influ-enced by the type of recruitment procedure used. For example, in one study, when the VT was set low (5-6 mL/kg), the UIP was 26 cm H2O.