regarding low flow versus high flow of gases during controlled ventilation

[frontier]

sirs,
i want to know whether you people prefer low flow of gases during controlled ventilation ,for example total 1.5 litre of gases per minute(900 ml of N2O +600 ml of 02) using a bain circuit or closed circuit.what are the advantages & disadvantages,regards

[jafo1964]

Theorotically low flow is not permitted in Mapleson D - Bain is the coaxial version
Mapleson circuits are eliminate CO2 by using adequate FGF to push it out of the APL valve to atmosphere or scavenging system if you have one.
Recommended FGF to prevent rebreathing is 2 to 2.5 times MV
But if you have an ETCO2 monitor you can reduce the flow and permit rebreathing and make sure that ETCO2 remains within acceptable limits. Still flows have to be relatively high.

Yes i use low flow with circle absorber.
N2O 1 L + 500ml of O2.

Advantages
Less use of IA -- cost containment
Conserves heat -- Decreases hypothermia
Humidification - decreases POPC
Decreased OT contamination  - lesser effects on all OT personnel
Conserves gas usage -- again cost effective

Esp with newer costly IA like sevoflurane - it is cost effective
2% sevo with flow rate of 1.5L uses lesser liquid agent than the same sevo 2% with flows of 4L or more litres
With low flow actual cost of using sevo is reduced

For details kindly refer the Exponential function of Lowe vs. the Linear function of Lin for low flow anaesthesia

Low flow also has its disadvantages esp with Sevo. Low flow has more incidence of Compound A production but that happens when flows are below 1 litre.

regs

[frontier]

thank you sir for your reply.regards

[aira93]

Regarding to the low  flow of versus, I would prefer a high flow of gases during controlled ventilation. How about you?




________________
Bathroom fan

[jafo1964]

the truth is that all of use either intermediate flow or high flow
very few people use low flow
because
it needs good machine
good monitoring
good understanding of concepts

is low flow then necessary?
newer Inhalationals will be more better,  but more costly
if you use low flow you can use better agents at a more economical rate


atmosphere needs to be protected
like cars and industries have stingent emission standards anaesthetists will alos have to follow it sooner or later

So it is inevitable that slowly but surely anaesthesia will move towards low flow

regs

[yogenbhatt1]

Low flow on Bains will be unscintific as Dr. Jafo mentioned.
But I have seen a few of our members use Bains Circuit in Circle absorber. What is the logic?? I cant imagine.
Low flow is best.
We use up about 16 ltrs of gases in Bains or 8 ltrs in other open circuits. What happens to Nitrous Oxide that goes in the atmosphere?
The only way to break up Nitrous is Lightening.
How much effective it is, only time will tell.
At this rate a time may come when Nitrous may be banned all over the world. Imagine what happens then.
May be your Anaesthesia machines will not be needed,
only IV routs will be preffered.
Be prepared now only and imagine tomorrow.
Regards.

[frontier]

sir,
  we often use 1-1.5 litre of O2+N20 ,but with good anesthesia machine in which oxygen analyser is there & constant EtCO2 monitoring.regards