1. Medical Training - Physiology & Pathophysiology - For internal use only

2. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20082 Objective of the Presentation This presentation on the physiology of the respiratory system gives participants an overview of of the anatomical structures required for normal respiration in a human being, the terminology used for respiratory mechanics and the normal values for a human subject. The area of pathophysiology covers known clinical pictures and indications for ventilation.

3. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20083 Contents Respiratory physiology Spontaneous breathing Respiratory mechanics Gas exchange Pathophysiology and clinical pictures Indications for ventilation Summary

4. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20084 Respiratory Physiology Coverage of an organism‘s energy needs requires –continuous supply of nutrients –oxygen (O 2 ) to obtain stored ATP (adenosine triphosphate) from cells. During the conversion CO 2 and water are released. Prerequisites: –Functional respiratory drive and respiratory musculature –Intact gas exchange unit (lung parenchyma) –Sufficient O 2 transport (blood circulation function).

5. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20085 Spontaneous Breathing Spontaneous breathing is triggered by a reflex. It is an unconscious process which – in contrast to other reflexes – can be partly controlled by holding one‘s breath. Stimulus to breathe is made up of the following –increase of the CO 2 level in the blood –decrease in O 2 level in the blood –decrease of pH level in the blood

6. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20086 Respiratory Mechanics Intrapulmonary pressure –Inspiration: < atmospheric pressure active process, overcoming the elastic retraction force of the lungs –Expiration: > atmospheric pressure passive process, by means of elastic retraction force of the lungs

7. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20087 Introduction and Brief Overview Ventilation/ Volume Tidal Volume (TV) is the volume of air that is inhaled in one normal breath (about 500ml/at rest 6-8ml/kg) Quelle: Schmidt, Thews, Lang, Physiologie des Menschen, Springer, 2000

8. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20088 Lung Volumes Tidal Volume (TV): 500-800 ml Total Capacity (TC): 6000 ml Residual Volume (RV): 1200 ml –Maximum Expiration Vital Capacity (VC): approx. 5000 ml –Difference between Total Capacity and Residual Volume Inspiration Capacity (IC) : 2500 – 3500 ml –Inspiration from resting end-expiratory position Functional Residual Capacity (FRC) : 2300 ml –Sum of Residual Volume and Expiratory Reserve Volume

9. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 20089 Resistance/ Compliance Resistance: Measurement of flow resistance of the respiratory system that must be overcome during inspiration and expiration. Compliance: Measurement of the lungs‘ intrinsic elasticity Describes the elastic properties of the respiratory system

10. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200810 Resistance Measure for airways resistance = flow resistance Defined by the pressure difference behavior between the beginning and end of a conduit (therefore, between the atmosphere and the alveoli) and the gas volume that flows through the conduit per time unit (= flow) R = Δp/V [R] = 1 mbar/l/sec In a healthy adult: 2 – 4 mbar/l/sec

11. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200811 Compliance Measure of the lungs‘expansibility Describes the elastic properties of the respiratory apparatus Defined as the ratio of volume change to the related pressure change: C = ΔV / Δp [C] = 1 ml/mbar Depends on the elasticity of the pulmonary fiber network, intrapulmonary fluid level and on surfactant activity.

12. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200812 Surfactant Surface active agent Substance which is active on the inner surface of the alveoli Reduction of surface tension by a factor of 15 to 20 Decrease of “opening pressure” of small alveoli Increase in lung compliance Prevention of alveoli collapse

13. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200813 Pressure-Volume Curve

14. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200814 Respiration Gas exchange between organism and environment –external respiration (at the alveolar level) –internal respiration (at the cellular level) O 2 consumption: 3 – 5 ml/kgKG/min CO 2 production: 3 ml/kgKG/min

15. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200815 External Respiration O 2 diffuses from the alveoli into the blood and CO 2 from the blood into the alveoli along the alveolar-capillary membrane

16. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200816 Gas Exchange (External Respiration) The gas exchange at the alveolar level depends on Ventilation Diffusion Perfusion Dead space ventilation intrapulmonary right-left shunt

17. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200817 Partial Pressures Depending on Airway pO 2 (mmHg)pCO 2 (mmHg) Atmosphere150-1600 Inspired air140-1500 Alveolar air10040 Arterial blood90 - 10040 Gem. venous blood4045 Cells< 5> 45

18. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200818 Disruption of O 2 Availability/Transport to Alveolar Level Decrease in O 2 availability (CO 2 enrichment) Mechanical disorders –Secrete accumulation –Swelling of mucus membranes (bronchial asthma, bronchitis) –Lengthening of exchange route (pulmonary edema) –Bronchial spasms –Foreign bodies –Tumor stenosis Disorder of Central Respiratory Control (head injury) Respiratory mechanics disability caused by trauma to thorax Failure of respiratory musculature (intoxication)

19. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200819 Disruption of O 2 Transport from Alveolar Level to Cellular O 2 Supply Impaired pulmonary perfusion (emphysema, ARDS) Heart failure Lack of volume (bleeding, burns) Impeded transport capacity of erythrocytes (intoxication) Impaired O 2 utilization – internal respiration (intoxication)

20. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200820 Indications for Ventilation Ventilation disorders –Trauma to thorax –Injuries of the diaphragm Diffusion disorders –Pulmonary edema Central respiratory disorders –SHT Perfusion disorders –Pulmonary embolism, emphysema Disorders of distribution

21. © WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO.KG, Medical Training Physiology & Pathophysiology, June 200821 Summary Basic knowledge of anatomy is a prerequisite for understanding respiratory physiology. Basic knowledge of respiratory physiology facilitates the understanding of respiratory disorders. Understanding of processes in respiratory physiology and standard values make possible patient-adapted care in cases of respiratory disorders and indications for ventilation.