D VAPORIZERS.pptx in anaethethiaachine o

It's a must know for all

1. VAPORIZERS Prof. A.I. Eshiet

2. Vaporizers Definition: This is a device that delivers a set concentration of a volatile anaesthetic agent. -It controls the vaporization of the volatile anaesthetic agent . -Output added to the fresh gas flow.

3. Vaporizers Classification: Mechanism for adding anaesthetic vapour -Variable bypass -Measured flow Internal Resistance of the Vaporizer -High: Plenum -Low: Drawover Temperature compensated(TEC)

4. Boyle’s bottle Vaporizers

5. Modern vapourizer

6. Schematic diagram

7. Vaporizers Classification: Plenum Draw over Dual Circuit- Vapour blender

8. Vaporizer Plenum Vaporizer -Driven by positive pressure from the anaesthetic machine. -Performance does not change with spontaneous breathing or mechanical ventilation. -Has high internal resistance. -The supply pressure remains constant.

9. Vaporizer Plenum Vaporizer: -The vaporizer is calibrated . -Delivers a precise concentration of the agent over a wide range of fresh gas flow. -Performance depends on SVP. -Vaporizer is designed for specific volatile anaesthetic agent. -It is a vaporizer outside circuit.

10. Vaporizers Plenum Vaporizer: -SVP of the volatile agent varies with temperature. -Designed to function within a specific temperature range. -Unidirectional -Variable bypass

11. Vaporizers Plenum Vaporizer Function: Splits incoming fresh gas into two streams. One stream passes through the bypass channel of the vaporizer. The second stream is diverted into the vaporizing chamber. The gas in the vaporizing chamber becomes fully saturated with the volatile anaesthetic agent. The saturated gas leaves the vaporizing chamber to mix with the other gas in the bypass channel before leaving the vaporizer. The ratio of the two streams; splitting ratio, determines the concentration of the agent delivered.

12. Vaporizer Draw-Over Vaporizer: Vaporizer in circuit. Low resistance Uses FGF at atmospheric pressure. Inefficient compared plenum vaporizer.. Driven by patient’s respiratory effort Robust and portable Adapted to field work eg . Military service.

13. Vaporizer Dual – Circuit(TEC 6 Vaporizer): -FGF does not enter the vaporizing chamber. -FGF passes through a separate channel to mix with pure vapour leaving the chamber at the outlet. -Designed specifically for desflurane because of its high SVP

14. Vaporizers Factors Affecting Vaporizer Output: -FGF : The concentration of the anaesthetic agent delivered by vaporizer is proportional to the volume of gas passing through the vaporizing chamber. - Surface Area -Increased by: 1.wick 2.metal baffles

15. Vaporizer Temperature: -Rise in temperature results in an increase in output. -Lost of latent heat of vaporization cause a fall In temperature and decrease in output.

16. Vaporizers Temperature Compensation: -Use of metal case with high thermal conductivity and specific heat capacity. -Bimetallic strip -Bellows -Electronic control -Automatic adjustment of the splitting ratio.

17. Vaporizer Gas Flow Rate: -Alters the total flow through the vaporizing chamber. At high flow rate, the gas leaving the Vaporizing chamber is less saturated. Composition of Carrier Gas: -Viscosity -Density

18. Vaporizer Boiling Point -Volatile agent with high boiling take a long time to vaporize. Ambient Pressure -Reduced ambient pressure result in an increase in output

19. DESFLURANE VAPOURIZER:SCHEMATIC DIAGRAM