Medical Training Physiology Pathophysiology For internal use only

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Medical Training - Physiology & Pathophysiology For internal use only

Medical Training - Physiology & Pathophysiology For internal use only

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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. 2

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 Contents • • Respiratory physiology Spontaneous breathing Respiratory mechanics Gas exchange Pathophysiology and clinical pictures Indications for ventilation Summary 3

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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). 4

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 p. H level in the blood 5

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 6

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 Introduction and Brief Overview Ventilation/ Volume Tidal Volume (TV) is the volume of air that is inhaled in one normal breath (about 500 ml/at rest 6 -8 ml/kg) Quelle: Schmidt, Thews, Lang, Physiologie des Menschen, Springer, 2000 7

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 8

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 9

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 10

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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. 11

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 12

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 Pressure-Volume Curve 13

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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/kg. KG/min • CO 2 production: 3 ml/kg. KG/min 14

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 15

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 Gas Exchange (External Respiration) The gas exchange at the alveolar level depends on • Ventilation • Diffusion • Perfusion • Dead space ventilation • intrapulmonary right-left shunt 16

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 Partial Pressures Depending on Airway p. O 2 (mm. Hg) p. CO 2 (mm. Hg) Atmosphere 150 -160 0 Inspired air 140 -150 0 Alveolar air 100 40 Arterial blood 90 - 100 40 Gem. venous blood 40 45 Cells <5 > 45 17

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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) 18

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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) 19

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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 20

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008

© WEINMANN GERÄTE FÜR MEDIZIN GMBH+CO. KG, Medical Training Physiology & Pathophysiology, June 2008 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. 21