ARTIFICIAL ARTIFICIAL LUNGLUNG

Kuwait UniversityCollage of Engineering and PetroleumChemical Engineering Department

Done by : Eng.Samar.T.Alqattan

Supervisod by : Prof. Mohammed Fahim

Dr. Amal Elkillani

Eng.samar alqattan , Chemical Engineering Department

AgendaAgenda

5 .Basic principles of operation

4.Classification of artificial lungs technology

6 .Mass transfer in artificial lungs

7 .Summary

3 .Comparison between natural and artificial lung

2 .Introduction

1 .Overview

OVERVIEWOVERVIEW

Eng.samar alqattan , Chemical Engineering Department

How we can breath How we can breath ??

The process of breathing consider to be a gas exchange a gas exchange by two parts:

1 )Respiratory systemRespiratory system ( O2 from atmosphere to lungs , CO2 from lungs to atmosphere )

2 )Blood system Blood system ( O2 from lungs to cells , CO2 from cells to lungs)

Eng.samar alqattan , Chemical Engineering Department

IntroductionIntroduction

Artificial lungs 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 blood oxygenatorsoxygenators

Eng.samar alqattan , Chemical Engineering Department

Each year nearly 350,000350,000 Americans die of some form of lung disease.

Artificial lungs Artificial lungs are used for :1)open-heart surgical procedures2)treating respiratory insufficiencies or failures.

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

ComparisonComparison of gas exchange parameters of the natural lung natural lung and current artificial lungs artificial lungs or blood oxygenators.

The O2O2 and CO2CO2 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

ClassificationClassification of artificial lung technology.

Eng.samar alqattan , Chemical Engineering Department

BASIC PRINCIPLES OF OPERATIONBASIC PRINCIPLES OF OPERATION

Hollow fiber 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

Eng.samar alqattan , Chemical Engineering Department

Eng.samar alqattan , Chemical Engineering Department

Determinants of Gas ExchangeDeterminants 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

Where :

where: αp : the solubility of the gas within the nonporous polymer Dp: diffusivity of the gas within the nonporous polymer

δ : the polymer layer thicknessPm : the polymer permeability to specific gases

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

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

Mass Transfer CorrelationsMass 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. Convectivemass transfer correlations have the general form

Eng.samar alqattan , Chemical Engineering Department

THE BLOOD OXYGENATORTHE 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

Properties of blood oxygenators currently Properties of blood oxygenators currently used clinicallyused clinically

Eng.samar alqattan , Chemical Engineering Department

ExampleExample

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 ?

SolutionSolution

= (1*10-2) ml/cm2/s/cm Hg * 2 m2 * 50 mmHg * ( 1cm / 10 mm) * ( 10000 cm / 1m ) * ( 1 lit / 1000 ml ) * ( 60 s/ 1 min ) = 60 lit/min 60 lit/min

Eng.samar alqattan , Chemical Engineering Department

SUMMARYSUMMARY

The natural lung natural lung represents a remarkable organ for gas exchange, and developing an artificial lung artificial lung that approaches the gas exchange prowess of the natural lung is a significant engineering challenge.engineering challenge.

Several research efforts are underway on the development of next-generation artificial lungs artificial lungs designed specifically for respiratory support of the failing lung.

THANK YOU FOR LISTENING

Eng.samar alqattan , Chemical Engineering Department