L1: Anesthetic Equipment (Granone) Flashcards
Machine divisions
1) High pressure (gas from cylinders/pipeline w/ pressure reduced to working pressure)
2) low pressure (once gas blends w/ anesthetic vapor and flowmeters, common gas outlet, and vaporizer)
3) breathing system
4) scavenging system
High pressure system components
1) Gas sources: pipeline, cylinders
2) Pressure regulator (first stage)
3) Oxygen flush valve
4) Flow control valve
PSI of oxygen when it comes out the wall
50-55 PSI
PSI And volume of full normal size “E” tank of O2
2200 PSI, 660 L
PSI and volume of large “H” tanks of O2
6900 L O2
2200 PSI
PISS =
Pin index safety system
-prevents interchanging of wrong tank w/ wrong gas
Pressure of cylinder contents proportional to:
Volume of gas in cylinder
Pressure of nitrous oxide in tank
745 PSI
pressure drops when 25% of contents remain; pressure drop proportional to volume
Chars. Of pressure reducing valve
-reduces gas pressure to working machine pressure (2200 PSI to 40-50 PSI of constant pressure w/o no flowmeter fluctuations)
Oxygen flush valve chars.
- direct connection b/w high pressure system and patient breathing circuit
- O2 to common gas outlet or patient circuit
- bypasses vaporizer
- delivers 35-75 L/min (unregulated)
- dilutes out system gas/anesthetic
- risk of over-pressurizing! Can cause pneumothorax, volutrauma, barotrauma
Flow control valves char.
- component of high pressure system and flowmeter
- gas passes through small orifice to flowmeter
- don’t overtighten knob
Flowmeter chars.
- May be more than one on a machine if multiple gases
- calibrated for a specific gas
- controls rate at which specific gas is delivered (L/min)
- Bobbin w/ a tapered tube
- rise proportional to gas flow through tube
- read bobbin at top, read ball in center
Mannifold
- connects flowmeter(s) to vaporizer
- order of flowmeters become important: oxygen should be downstream and closest to the vaporizer so no matter what there is a greater chance a flow will reach the p
Vaporizers char.
-turns liquid anesthetic into vapor and delivers at clinically useful concentrations
MAC of iso
1.2-1.3%
Classifications of vaporizers
1) Concentration calibrated
2) Flow over (DNK)
3) Thermocompensated - doesn’t fluctuate output based on outside temp.
4) Out of circuit
5) Agent specific - designed for only iso or only sevo
6) Plenum
Desflurane vaporizer chars.
- has high saturated vapor pressure
- low boiling point (23.5 C)
- must always be plugged in
- must be heated and vaporized to deliver adequate anesthesia to patient
- expensive and has restrictions
Main fxs of breathing systems
delivery of inhalant and oxygen to patient, w/ removal of CO2 and excess anesthetic gases
4 breathing system categories
Open
Semi-open
Semi-closed
Closed
Open breathing system chars.
- No reservoir for supplied gas/anesthetic
- No reservoir for waste anesthetic gas
- ie: cotton ball soaked in inhalant in chamber
Semi-open breathing system chars.
- may or may not have reservoir for anesthetic gases
- no rebreathing of expired gases
- no CO2 absorption
- Ex: Bain, Jackson-Rees, Ayre’s T piece
Semi-closed breathing system chars.
- DOES have reservoir for anesthetic gases
- absorption of carbon dioxide
- can have low (22 ml/kg/min) flow of fresh gas
- low flow is metabolic requirement for oxygen
- Ex: circle breathing system
Closed breathing system chars.
- has reservoir for anesthetic gases
- absorbs CO2
- has complete rebreathing of expired gases, excluding CO2
- O2 flow meets patient metabolic O2 requirements
Advantages of closed breathing system
- more economical
- conservation of heat and humidity
- reduced anesthetic gas pollution
- reduced risk of barotrauma
- aid in diagnosis of hypermetabolic state
