lecture 3- the anesthesia machine

wilson

what are the parts of he high pressure system

A. oxygen cylinder

B. cylinder valve

C. cylinder pressure gauge

D. Regulator (or reduction

valve)

what are the intermediate pressure system

oxygen flush/bypass valve

what are the parts of the low pressure system

E. flow meter

F. vaporizer

H. common gas outlet

I. common gas inlet

J. one-way valves

•inspiratory

•expiratory

K. pop-off valve

what are parts of the high pressure system

A B C D

what are parts of the intermediate pressure system

G

what are parts of the low pressure system

E F H I J K

from the oxygen cylinder to the pressure reducing valve (aka regulator)

high pressure system

from the pressure reducing valve to the flowmeter

intermediate pressure system

from the flowmeter to the common gas outlet

low pressure system

what is this

cryogenic liquid supply

what is this

compressed gas in cylinders

what is this

oxygen concentrator

explain compressed gas in cylinders

E cylinder

G and H will set up as a central supply system

typically 2 banks connected to common manifold that converts them into one continuous supply

large liquid oxygen containers installed at facilities that have a fairly constant demand

cryogenic liquid supply

how do oxygen concentrator increase O2

absorbing nitrogen onto a moleculra sieve and allows O2 and trace gases to pass through —> resulting in O2 concentration of 90-96%

safety to remember for oxygen cylinder

must be inspected and tested at least every 5 years

use color coding oxygen=green in US

what are oxygen cylinder made of

steel, steel carbon fibers, or aluminum

why should you open oxygen cylinder valve slowly

because rapid recompression of gas generates heat

what is the capacity and pressure for E oxygen xylindres

600 L capacity

2200 psi

what is the capacity and pressure limits of H oxygen cylinder

6900 liters

2200 psi

what is the left arrow

handle attach

what is the right arrow

port

what is this

conical depression to receive yoke retaining screw

what is this

hanger yoke: orients nad supports cylinder, provides gas-tight seal

what is this

cylinder valve

what is the blue arrow

pressure gauge

what is the yellow arrow

regulator

what does the regulator do

reduces the gas pressure from the cylinder to a usable level of a constant 50 osi

specific for. gas and tank size

terminates in a gas specific male DISS fitting

what is the cylinder pressure gauge

must be installed down stream of each pressure regulator

calibrated in psi

allows user to calculate remaining liters in tank or pipeline pressure

what is the red

regulator

what is the green

cylinder pressure gauge

what is this in psi

1500 psi

what is this in liters

when should you change cylinder

when pressure < 500 psi

what is the oxygen flush valve

receives O2 from the pipline inlet or cylinder pressure regulator and directs a high unmetered flow directly to the common gas outlet

what is the L/min of oxygen flush valve when activated and what can it cause

35 to 75L/min pisslbe bartrauma so nerver use when connected to patient

which is correct

right correct

indicates rate of flow of gas passing through

flow meter

directions ot turn flow meter

Turn control knob counterclockwise to increase flow and clockwise to decrease flow (do not over tighten!)

has height of the flow meter increase

more gas flow

• Only present on a rebreathing system – allows gases to travel in one direction as the patient breathes

• Inspiratory valve

• Expiratory valve

unidirectional valves

disadvantages of unidirectional valves

increases resistance to breathing; if one or both valves are leaky ➔ patient will rebreathe CO2

• If valves are sticky, pressure in the system and against breathing in and out!

ways to monitor

assess the machine before and during use

watch your patient closely

capnograph to monitor breaths

• A device that changes a liquid anesthetic agent into its vapor

and adds a controlled amount of that vapor to the fresh gas

flow going into the patient breathing system.

vaporizer

how does a vaporizer dilute vapro

by splitting the gas flow that passes through the vaporizer

• by pass the vaporizer outlet

  • vaporizing chamber

oh no! i knocked over the vaporizer what do I do now

• Generally, if vaporizer is tipped it should be flushed with a high O2 flow rate for the max time recommended by manufacturer. Ideally, vaporizer should be emptied prior to transport, left in upright position, and dial set to “0” position.

• Overfilled vaporizer may deliver lethal concentrations or cause vaporizer failure with zero output.

• If filled with wrong agent, vaporizer must be completely drained and all liquid discarded. O2 should be run through until no agent detected

what is the purple bottle of liquid anesthetic

isoflurane

what is the yellow bottle of anesthetic

sevoflurane

receives all gases and vapors from the machine and delivers the mixture to the breathing system

common/fresh gas inlet and outlet

where does the common/ fresh gas inlet attach

close to the patient on the non-rebreathing system so never activate the oxygen flush valve when using this type of system

when using a reservoir bag how many breaths does this allow

5-6

what are reservoir bags used for

to monitor frequency of respiratroy rate and compliance of patient’s pulmonary system during assisted ventilation

what is the formula to determine what size reservoir bag to use

body weight x tidal volume x 5

what are adjustable pressure limiting (“pop off”) valve used for

to control pressure in the breathing system

transiently close APL to deliver manual ventilation to patient

other wise must be kept open at all time

what are the top 3 killers

closed pop off valve

too little O2

too high vaporizer setting

what are some safety concerns

• Improper cylinder storage

• Tipping over vaporizer

• Wrong inhalant in vaporizer

• Overfilling vaporizer

• Using oxygen flush valve when attached to a patient

• O2 and N2O are flammable

Cylinder valve, pressure regulator, or gauges should never come in contact with

oils, greases, organic lubricants, rubber or combustible substances

how to perform a machine leak test (aka machine pressure check)

1. make sure O2 flow meter is off

2. close the APL (pop-off) valve

3. occlude the patient end of the Y-piece with a hand, finger, or syringe plunger

4. use O2 flowmeter to fill system can use very short burst from flush to fill large bags

5. observe the pressure guage for at least 10 seconds (suggest 30 seconds)

• If no leak observed, proceed to step 6.

• II. If leak observed (i.e. drops > 1 cmH20/sec), slowly titrate the O2 flow meter up to maximum of 300 mL/min:

  • a) If this stops the leak, the machine and breathing system is acceptable to use.

  • b) If it takes >300 mL/min of O2 to stop the leak, the machine and breathing system should not be used until the source of the leak is identified.

6. release APL valve

   1. remove occlusion from Y-piece