RespiLab RESPILAB: A VIRTUAL LABORATORY FOR THE ANALYSIS OF HUMAN RESPIRATORY CONTROL SYSTEM I OC I n s t i t u t e o f I n d u s t r i a l a n d C o n t r o l E n g i n e e r i n g I O C I n s t i t u t e o f I n d u s t r i a l a n d C o n t r o l E n g i n e e r i n g Alher Mauricio Hernandez 1, Miguel Angel Mañanas 1, Ramon Costa-Castelló 2 1 Department of Automatic Control (ESAII), Biomedical Engineering Research Center (CREB) 2 Institute of Industrial and Control Engineering (IOC)

RespiLab I.Introduction II.Objectives III.The Respiratory Control System Model descriptionModel description Ventilatory stimuliVentilatory stimuli Optimization of respiratory frequencyOptimization of respiratory frequency Restrictive and obstructive diseasesRestrictive and obstructive diseases IV.Virtual Lab Description Tool developmentTool development Interactive elementsInteractive elements Plots and examplesPlots and examples V.Conclusions Content Introduction Objectives Resp. System Resp. System Virtual Lab Virtual Lab Conclusions

RespiLab Christian Darkin / Science Photo Library ® Content Introduction Objectives Resp. System Resp. System Virtual Lab Virtual Lab Conclusions Introduction Biomedical Engineering (BME) is the application of engineering sciences and technology to medicine and biology. The interdisciplinary nature of this activity implies interplay and overlapping of interest and effort between engineering and biologic points of view. Engineers do not need a deep knowledge of certain medical topics (and vice versa). BME is different to other engineering areas in the sense of obtaining results from experimental procedures and reproducing real physiological situations.

RespiLab Introduction It is very difficult and expensive to interact with the human being body and even dangerous in certain situations. The field of BME includes many career areas, and one of them is the application of engineering system analysis (physiologic modeling, simulation, and control) to biologic problems. The respiratory control system is a nonlinear, multi-output, delayed-feedback dynamic system which is constantly being perturbed by physiologic and pathologic disturbances. Bsip, ciot/ Science Photo Library ® Bsip Vem / Science Photo Library ® Content Introduction Objectives Resp. System Resp. System Virtual Lab Virtual Lab Conclusions

RespiLab Objectives Developing a virtual laboratory to study the respiratory system under normal conditions and pathological situations. Proposing the use of Virtual Labs in the study of respiratory system in BME programs, in order to overcome the drawbacks of interaction with human body. Designing a Virtual Lab in a visually attractive and interactive way. Content Introduction Objectives Resp. System Resp. System Virtual Lab Virtual Lab Conclusions

RespiLab The Respiratory Control System 1. Model Description (I) Content Introduction Objectives Resp. System Resp. System Virtual Lab Virtual Lab Conclusions The respiratory control system is dedicated to the exchange of O 2 and CO 2. Control of ventilation is automatic and normally involuntary. Respiratory system adjusts alveolar ventilation (V A ) to preserve homeostasis, that is to say, so that the arterial CO 2 pressure (PaCO 2 ), and arterial O 2 pressure (PaO2), remain practically constant or under acceptable ranges.

RespiLab The model described in (Fincham and Tehrani, 1983) and (Tehrani, 1993) considers a controller whose parameters of respiratory pattern are calculated every cycle as it happens physiologically. Lung volume changes following a sinus during the respiratory cycle to simulate more properly inspiration and expiration intervals. The Respiratory Control System 1. Model Description (II) 1/f V A t. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab The Respiratory Control System 1. Model Description (III) Content Introduction Objectives Virtual Lab Virtual Lab Conclusions 1/f V A t. In the plant, there are blocks and variables indicating physiological processes: Gas concentrations in veins and arteries. Gas exchange in body tissue and brain. Circulatory mixing and circulation time delay from tissues to chemoreceptors. The model includes important variables in the respiratory pattern generation as tidal volume (V A ), and respiratory frequency (f). The model has been implemented in Matlab/Simulink® Resp. System Resp. System

RespiLab The Respiratory Control System 2. Ventilatory Stimuli Hypercapnia: It corresponds to a presence of CO 2 in the inhaled gas or CO 2 retention. An input variable, P I CO 2, is considered whose value is 0 torr (0 % of atmospheric pressure) in normal conditions and increases with the hypercapnic stimulus. Hypoxia: This stimulus can result from disturbances of respiration or a reduction in pressure of inspired air as occurs at high altitudes. For the simulation, an input variable, P I O 2, is considered with values lower than 159 torr (21% of atmospheric pressure), corresponding to normal conditions at sea level. Exercise: During exercise, O 2 consumption and CO 2 production ( ), rise to counterbalance the metabolic increased demand. A value of. is considered at rest, and increases with exercise. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab 3. Optimization of Respiratory Frequency Three well known different equations to calculated the respiratory frequency on the basis of optimization of respiratory work are considered: (Otis et al., 1950). (Mead, 1960) (Widdicombe and Nadel, 1963) All three can be used in the model in order to evaluate differences in the respiratory variables at different levels of stimulus. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System The Respiratory Control System

RespiLab 4. Restrictive and Obstructive Diseases There are two main types of lung disease, obstructive and restrictive, which are related to changes in Resistance (R rs ) and Elastance (E rs ) respectively. These two mechanical parameters are included in respiratory frequency equations. Restrictive lung diseases are caused either by an alteration in lung tissue or by disease of the chest wall, or neuromuscular apparatus. E rs In obstructive lung conditions, airways are narrowed, usually causing an increase in the time it takes to empty the lungs. R rs Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System The Respiratory Control System

RespiLab Virtual Lab Description 1. Tool Development Presented software application is based on Easy Java Simulations (EJS), an open source java-based tool that allows creating interactive dynamic simulations. SIMULINK Model (Fincham et al., 1983) EASY JAVA The model is based on MATLAB/Simulink®. The simulation runs in Simulink while is controlled by Easy Java. The interface to the user has been designed and implemented in EJS. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab Virtual Lab Description 2. Interactive Elements (I) In the interactive module parameters can be changed by means of sliders and tabs in order to simulate different ventilatory conditions. A multisignal scope can be seen when this option is selected by the user. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab Virtual Lab Description 2. Interactive Elements (II) Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab Virtual Lab Description 3. Plots and Examples (I) One of the two kinds of plots are shown when the corresponding tab of signal scope is selected by the user: A change from resting conditions to a specific level of exercise is produced at 90 seconds. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab Virtual Lab Description 3. Plots and Examples (II) With the objective of evaluate differences in the breathing pattern between a healthy person and a restrictive patient, at 3 minutes E rs changes from normal conditions to values corresponding to a restrictive patient. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab Virtual Lab Description 4. Respilab Demo Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System

RespiLab

RespiLab Conclusions This laboratory is completely graphic and interactive, so it can be used to illustrate the behavior of human respiratory control system under certain circumstances or pathologies and the influence of relevant parameters in the system.This laboratory is completely graphic and interactive, so it can be used to illustrate the behavior of human respiratory control system under certain circumstances or pathologies and the influence of relevant parameters in the system. RespiLab allows the students and researchers obtain sensations and experience that would be very difficult otherwise because of the difficulties in performing experimental human studies.RespiLab allows the students and researchers obtain sensations and experience that would be very difficult otherwise because of the difficulties in performing experimental human studies. The use of virtual laboratories and interactivity in BME has proved to be an efficient way to shortcut the learning process an improve the students capabilities.The use of virtual laboratories and interactivity in BME has proved to be an efficient way to shortcut the learning process an improve the students capabilities. The tool has been built combining MATLAB/Simulink and EJS. While MATLAB/Simulink allows to implement complex models in straightforward manner, EJS allows to design attractive views and introduce interactivity easily.The tool has been built combining MATLAB/Simulink and EJS. While MATLAB/Simulink allows to implement complex models in straightforward manner, EJS allows to design attractive views and introduce interactivity easily. Content Introduction Objectives Virtual Lab Virtual Lab Conclusions Resp. System Resp. System