1. Hyperoxyc test in man MUDr. Dobroslav Hájek, CSc. MUDr. Michal Jurajda

2. The atmosphere N 2 78,1% O 2 20,9%O 2 20,9% CO 2 0,03% noble gases 1%

3. Concentration of gases Partial pressure- pressure of the given gas in the mixuture of gases.

4. atmospheric pressure ????

5. Ventilation under extrem pressure conditions High altitudes – low pressure Diving – high pressure Remember: optimal pO 2 cca 21 kPa

6. Hyperbaric oxygenation - increases physically dissolved oxygen in blood and tissues

7. Hyperbaric therapy is used in: 1.CO intoxication. 2.Air embolism. 3.Decompression. 4.Anaerobic infections. 5.Non healing wounds

8. Hemoglobinu saturation

9. Oxygen measurements saturometer – saturation of Hb (%) oxymeter - paO 2 (Pa) lung function Fi O 2 paO 2

10. Right to left shunt Hypothetical fraction of blood flow (right ventricle output) passing the lungs without beeing oxygenated.

11. Right to left shunt Anatomical Functional

13. Dead space The dead space (alveoli with low ventilation/perfusion ratio) incrase the right-to left shunt.

14. paO 2 = S.pvO 2 +(1-S).piO 2 paO 2 = S.pvO 2 -S.piO 2 + piO 2 S.pvO 2 -S.piO 2 = paO 2 -piO 2 S.(pvO 2 -piO 2 ) = paO 2 -piO 2 S = (paO 2 -piO 2 )/(pvO 2 -piO 2 ) S = (piO 2 -paO 2 )/(piO 2 -pvO 2 )

17. Remember When the increased right-to left shunt is caused by vascular bed involvement (typically: lung embolism) the response of partial oxygen pressure in arterial blood (paO 2 ) to oxygen administration is very poor. (The paO 2 increase is very low when oxygen is administered)

18. Clinical cases Poisoning by hyptotic or sedative drugs (e.g. barbiturates, benzodiazepins, morphin) Foreign body (corpus alienum) in bronchus with its obstruction Ventilation/perfusion unbalance.

19. The objective Estimate rght to left shunt

20. Material Transcutaneous oxymetr Medicinal oxygen in gas bottle with pressure reduction valve and flow regulation valve. Mask with gas blender and delivery hose

22. Clarc electrode Polarographic electrode that measures the partial oxygen pressure in the given space At a given constant voltage the current is proportional to the partial pressure of oxygen.

23. Leland C. Clark

24. The method Increasing FiO 2 increases p a O 2 p a O 2 can be measured in arterial blood or in arterialised capillary blood by transcutaneous oxymeter (heated electrode). The incerease of p a O 2 is dependent on FiO 2 and right to left shunt.