How many time constants are necessary for 95 of the tidal volume ...

[mp14]

How many time constants are necessary for 95 of the tidal volume (VT) to be delivered from a mechanical ventilator?
 
  a. 1
  b. 2
  c. 3
  d. 4

Question 2

Compute the inspiratory time necessary to ensure 100 of the volume is delivered to an intubat-ed patient with a Cs = 60 mL/cm H2O and the Raw = 6 cm H2O/(L/sec).
 
  a. 0.36 second
  b. 0.5 second
  c. 1.4 second
  d. 1.8 second

[underwood14]

Answer to Question 1

ANS: C
One time constant allows 63 of the volume to be inhaled; 2 time constants allow about 86 of the volume to be inhaled; 3 time constants allow about 95 to be inhaled; 4 time constants allow about 98 to be inhaled; and 5 time constants allow 100 to be inhaled.

Answer to Question 2

ANS: D
Time constant (TC) = C (L/cm H2O)  R (cm H2O/(L/sec)). 100 of the volume will be delivered in 5 time constants. Therefore, multiply 5 times the time constant.

[mp14]

Great answer, keep it coming

[gcook]

Thanks for the timely response, appreciate it