BIOFLUID DYNAMICS OF THE HUMAN RESPIRATORY SYSTEM

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31 Οκτ 2013 (πριν από 4 χρόνια και 9 μέρες)

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BIOFLUID DYNAMICS OF THE
HUMAN RESPIRATORY SYSTEM

The future belongs to those who
believe in the beauty of their
dreams

Eleanor Roosevelt


from left to right:

1. Hong Guo 3. Tejas Choksi,

2. Amaury Pita 4.Julian Bedoya

Contributors

Description of The Respiratory System

www.lungusa.org

Functions of Biofluids in The Respiratory
System

General functions of blood:



Transportation


pH regulation and ion composition


Restriction of fluid losses at injury sites


Defense against toxins and pathogens


Stabilization of body temperature


Composition of Inhaled and Exhaled Gases


users.tpg.com.au


Alveolar

Organization


Martini, 2001

Mechanics of Ventilation

The change in

alveolar ventilation:


Is
inversely

related
to changes in
arterial Pa
CO2

and


Directly
proportional to total
body CO
2

production.



www.biosci.ohiostate.edu


Effects of
pH

and
partial pressure of oxygen

on
the
percent saturation of hemoglobin


www.biosci.ohiostate.edu


Change in extra cellular pH due to change in
alveolar ventilation rate

www.ursai.kcom.edu

Oxygen Transport


Oxygen
-
hemoglobin saturation curve

www.biosci.ohiostate.edu

Carbon Dioxide Transport


www.ursai.kcom.edu

Pulmonary Volumes and Capacities

www.biosci.ohiostate.edu

Conceptual Model of Respiratory System

Menon et.al 1984

Pulmonary Cellular Mechanics


Changes in lung volume affects: Airflow; Aspects
of lung metabolism; Function and growth.



Mechanical forces

may be secondary to
gradients in gravity, motion, osmotic forces and
interactions between cells and/or matrix
components.



Cells within a complex 3
-
D structure such as the
lung are likely to be subjected to different


physical forces.

Respiratory Fluid Mechanics


Continuity Equation
:





Navier
-
Stokes Equation
:


(for 1
-

D, incompressible fluid & for a
constant viscosity)



Laminar velocity profile for fully
developed flow

Fung, 1990


Glottis shown during inspiration (a) and
expiration (b)


Renotte,et.al 2000

Pressure Drop As a Function of Airway
Generation




Filled circles

represent actual values.

o

Open circles represent values predicted by


Poiseuille’s Law.

Fung, 1990

Gas Flow In Bifurcation


2
-

D plane schematic of CFD
model used for flow in bifurcation


Liu, et.al 2002


Dean vortices observed during
flow in a curved bifurcation

Caro, et.al 1978

Velocity Profiles for Pulsatile Flow vs.
Womersley number



Womersley number
is defined as:




Where:



= Circular frequency

ν

= Kinematics


viscosity

Caro, et.al 1978

Flow Visualization


The flow patterns at peak systole in the
main pulmonary arteries

Sung, et.al 1998

CFD for Respiratory System


CFD model of the human nasal cavity

www.wmrc.com

Mechanical Ventilation



Mechanical Ventilator: Volume Ventilators, High
Frequency Ventilators, Pressure Ventilators

www.addenbrookes.org.uk

Direct Contact and Membrane
Oxygenators


www.vuse.vanderbilt.edu


Direct Contact

Membrane

Heart

Lung Machine with An Oxygenator

Connected to The Patient


www.vuse.vanderbilt.edu

Recent Advances


IMO (
Intravenous or Impantable
Membrane Oxygenator
)


artificial lung device

www.vuse.vanderbilt.edu

Artificial Impantable Lung

www.vuse.vanderbilt.edu

Thank you

The future belongs to those who
believe in the beauty of their dreams

Eleanor Roosevelt