6 Anesthesia Machine Flashcards
How to check low pressure leak, best test of what
Negative pressure test, bulb to common gas outlet, fails if inflates in 10 seconds. All flows and vent off, test each vaporizer (best test of vaporizer leak)
How to do high pressure leak test, how check valve affects what is tested
Close apl and pressurize to 30. If check valve- assesses breathing circuit and low p system up until valve. If no check valve- entire low pressure system
5 tasks of oxygen
02 pressure failure alarm, 02 pressure failsafe device, flowmeter, flush valve, and vent drive gas
Cylinder colors air, 02, nitrous
Air: black and white. 02: green. Nitrous: blue
Air: max p, max vol, pin
1900 psi, 625 l
O2: psi, L
1900 psi 660 l
Nitrous: psi, L, wt when full v empty
745 psi, 1590l. 20.7 lb, 14.1 lb
How to calc time left in cylinder
L/psi when full = contents remaining /psi. Then divide answer (L) by LPM flow rate
When to change nitrous tank
Any time it falls below 745 psi
Safety relief devices for cylinder
Fusible plug that melts w elev temp (bismuth, lead, tin, cadmium), valve that opens at elev pressures, a frangible disc that ruptures under pressure
Failsafe is in which system, 2 components
Intermediate. Alarm when 02 pressure below 30 psi. Stops or dec nitrous when pressure in 02 pipe falls below 20 psi
What hypoxia prevention device does
Limits n20 flow to 3x the 02 flow
Reynolds: laminar v turbulent dependent on what
Laminar- gas viscosity. Turbulent- gas density
Fi02 calc
Air flow rate x21 plus 02 flow ratex100 / total flow rate
With fresh gas coupling how to calc tidal vol delivered
Vt set on vent + fgf on insp - vol lost to compliance
How to calc vol lost to circuit
Compliance x peak pressure
Pumping effect
Increases vaporizer output, anything that causes gas that has left vaporizer to re-enter it
What increases pumping effect
Low fgf, low conc dial setting, low levels of anesthetic in vap chamber
How to calc how long vaporizer agent will last
Ml used per hr= vol% x fgf (l/min) x 3
How to calc vaporizer output at elevation
Normal dial setting in % x 760 / ambient pressure mmhg
How altitude effects des output
Lower pressure/higher altitude requires higher setting.
First monitor to detect a pipeline crossover
O2 analyzer
02 flush valve pressure and rate q
50 psi, 35-75 l/min
2 ways to reduce barotrauma risk
Decoupling fresh gas and insp pressure limiter
When pos pressure and neg pressure relief valves open
75 cm h20 and -8 cm h20
Variables in VCV vs PCV
VCV: PIP, PCV: TV, insp time
Pts w low compliance
Preg, obese, lap, ARDS
When bipap is useful
Pts w COPD when CPAP isn’t enough
What is a/w pressure release vent, when useful
Spont vent mode like bipap, released at preset intervals to help exhale. Useful in ARDS
IRV: useful in who, risk of what, requires what
Small FRC or ARDS. Risk of auto peep/breath stacking. Req sedated and paralyzed
Soda lime rxn
CO2 + h20= h2co3. H2co3 + Naoh= na2co3 + h20 + heat. Na2c03 + ca(oh)2 = caco3 + naoh
Best mesh size for soda lime
4-8 mesh
When ph falls to what will ethyl violet change color
10.3
Desiccated soda lime inc produc of what, IA most to least. And what with only Sevo
CO. Des, iso, sevo. Compound A.
Most unstable IA in presence of soda lime
Sevo
Benefits of amsorb plus, what it uses. Cons
Caoh. No CO produc, almost no compound a, lower fire risk. Cons: less absorptive than soda lime
Max ppm halogenated alone, nitrous alone, and both
Halogenated 2 ppm, nitrous 25 ppm, both: <0.5 and 25
Water content of soda lime
15%
