RETENTION - CLEARANCE

1
RETENTION - CLEARANCE
Yves Alarie, Ph.D Professor Emeritus
University of Pittsburgh,USA
2
A. MODEL A model proposed by the Task Group on
Lung Dynamics is used. This model is shown in
Figure 18 and includes the following items
previously presented.
3
a) Mass concentration in the air. b)
Particle size to determine percentage
deposition in each portion of the respiratory
tract. c) Class of
particles in terms of clearance
time.
4
B. INPUTS FOR THE MODEL These are given in Table
10 and include the following D1 Total dust
concentration in inhaled air (mg/m3) D2 Total
dust concentration in exhaled air
(mg/m3) D3 Total dust deposited in N-P
compartment (mg) D4 Total dust deposited in T-B
compartment (mg) D5 Total dust deposited in P
compartment (mg)
5

C. OUTPUTSFOR THE MODEL CLEARANCE,HALF-LIVES,PATH
WAYS AND MECHANISMS These are given in Table 10
in an attempt to summarize all of these items.
First, look at Figure 18, for each letter on this
Figure there is an explanation for it in Table
10. Dont believe the numbers in Table 10. Use
them for relative comparisons rather than
absolute numbers.
6

• F. IMPLICATION OF THE MODEL
• With availability of computers it is now easier
  to predict aerosol accumulation and clearance in
  the respiratory tract (17,18).
• An example

7
Click for larger picture