1. Artificial lung Done by : Eng.Samar.T.Alqattan
Kuwait University
Collage of Engineering and Petroleum
Chemical Engineering Department
Artificial lung
Done by : Eng.Samar.T.Alqattan
Supervisod by : Prof. Mohammed Fahim
Dr. Amal Elkillani

2. Eng.samar alqattan , Chemical Engineering Department
Agenda
1. Overview
2. Introduction
3. Comparison between natural and artificial lung
4.Classification of artificial lungs technology
5. Basic principles of operation
6. Mass transfer in artificial lungs
7. Summary
Eng.samar alqattan , Chemical Engineering Department

3. Eng.samar alqattan , Chemical Engineering Department
Overview
How we can breath ?
The process of breathing consider to be a gas exchange by two parts:
1) Respiratory system
( O2 from atmosphere to lungs , CO2 from lungs to atmosphere )
2) Blood system ( O2 from lungs to cells , CO2 from cells to lungs)
Eng.samar alqattan , Chemical Engineering Department

4. Eng.samar alqattan , Chemical Engineering Department
Introduction
Artificial lungs : are medical devices designed to take over the respiratory function of the lung, which is to oxygenate the blood and remove carbon dioxide
Current artificial lungs are also known as blood oxygenators
Eng.samar alqattan , Chemical Engineering Department

5. Eng.samar alqattan , Chemical Engineering Department
Each year nearly 350,000 Americans die of some form of lung disease.
Artificial lungs are used for :
open-heart surgical procedures
treating respiratory insufficiencies or failures.
Eng.samar alqattan , Chemical Engineering Department

6. Eng.samar alqattan , Chemical Engineering Department
The alveolar-capillary membrane in the natural lung showing intimate contact between gas and blood in the lung
Eng.samar alqattan , Chemical Engineering Department

7. Eng.samar alqattan , Chemical Engineering Department
Comparison of gas exchange parameters of the natural lung and current artificial lungs or blood oxygenators.
The O2 and CO2 diffusing capacities of the lungs are proportional to the gas exchange area of the alveolar-capillary membrane and to the inverse of the diffusion distance across the alveolar-capillary membrane into blood.
Eng.samar alqattan , Chemical Engineering Department

8. Eng.samar alqattan , Chemical Engineering Department
Classification of artificial lung technology.
Eng.samar alqattan , Chemical Engineering Department

9. Eng.samar alqattan , Chemical Engineering Department
BASIC PRINCIPLES OF OPERATION
Hollow fiber membranes form the basic gas exchange units of contemporary artificial lungs (usually made of often polypropylene) and are small polymer tubes with microporous walls of 20 to 50 µm thickness and with outer diameters from 200 to 400 µm.
Scanning electron micrograph of microporous hollow fiber membranes used in artificial lungs. The walls of the fibers (right) contain submicron pores where respiratory gases diffuse.
Eng.samar alqattan , Chemical Engineering Department

10. Eng.samar alqattan , Chemical Engineering Department

11. Eng.samar alqattan , Chemical Engineering Department

12. Eng.samar alqattan , Chemical Engineering Department
Determinants of Gas Exchange
The overall O2 exchange rate :
The gas exchange permeance for CO2 removal:
The overall transfer resistance in an artificial lung :
Eng.samar alqattan , Chemical Engineering Department

13. Eng.samar alqattan , Chemical Engineering Department
Where :
Where:
αp and Db are the effective solubility and diffusion coefficient of the diffusing gas in blood
δ bl : is an average boundary layer thickness
where :
αp : the solubility of the gas within the nonporous polymer
Dp: diffusivity of the gas within the nonporous polymer
δ : the polymer layer thickness
Pm : the polymer permeability to specific gases
Eng.samar alqattan , Chemical Engineering Department

14. Eng.samar alqattan , Chemical Engineering Department
illustrates the membrane and blood-side diffusional resistances to gas exchange in artificial lungs
Eng.samar alqattan , Chemical Engineering Department

15. Eng.samar alqattan , Chemical Engineering Department
Mass Transfer Correlations
Classical diffusional boundary layer on a flat surface. .
The blood-side permeability, Kb, for artificial lungs can be estimated from mass transfer correlations obtained for flow through bundles of hollow fiber membranes. Convective
mass transfer correlations have the general form
Eng.samar alqattan , Chemical Engineering Department

16. Eng.samar alqattan , Chemical Engineering Department
THE BLOOD OXYGENATOR
The key design considerations in blood oxygenators include:
1) minimizing the resistance to blood flow,
2)reducing the priming volume,
3) ensuring easy debubbling at setup,
4)and minimizing blood activation and thrombogenicity.
Eng.samar alqattan , Chemical Engineering Department

17. Eng.samar alqattan , Chemical Engineering Department
Properties of blood oxygenators currently used clinically
Eng.samar alqattan , Chemical Engineering Department

18. Eng.samar alqattan , Chemical Engineering Department
Example
If membrane permeance dictated overall gas exchange, an artificial lung with 2 m2 membrane area perfused with blood at a PCO2 of 50 mm Hg and a diffusion coefficient of 1*10-2 ml/cm2/s/cm Hg Determine the gas exchange rate for CO2 removal ?
Solution
= (1*10-2) ml/cm2/s/cm Hg * 2 m2 * 50 mmHg * ( 1cm / 10 mm) *
( cm / 1m ) * ( 1 lit / 1000 ml ) * ( 60 s/ 1 min ) = 60 lit/min
Eng.samar alqattan , Chemical Engineering Department

19. Eng.samar alqattan , Chemical Engineering Department
SUMMARY
The natural lung represents a remarkable organ for gas exchange, and developing an artificial lung that approaches the gas exchange prowess of the natural lung is a significant engineering challenge.
Several research efforts are underway on the development of next-generation artificial lungs designed specifically for respiratory support of the failing lung.
Eng.samar alqattan , Chemical Engineering Department

20. Thank you for listening
Eng.samar alqattan , Chemical Engineering Department