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

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

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

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

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

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

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

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

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

Eng.samar alqattan , Chemical Engineering Department

Eng.samar alqattan , Chemical Engineering Department

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

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

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

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

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

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

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) * ( 10000 cm / 1m ) * ( 1 lit / 1000 ml ) * ( 60 s/ 1 min ) = 60 lit/min Eng.samar alqattan , Chemical Engineering Department

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

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