Perioperative Sweating cases!

[DrAmir0078]

Where did you come up with these FGF settings??

Dr.btbam,
I had learned this settings from my Seniors, all our adult patients gets 7 Lt/min flow of Oxygen, please tell us if this is wrong, I probably need to do a research for cost effectiveness regarding Oxygen cylinder, it is going to be revolutionary.
I have to make alive video of our machine and tell you what we are doing!

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[DrAmir0078]

Wait, Iraq has HIPAA?

Like the Health Insurance Portability and Accountability Act of 1996? I know we were "greeted as liberators", but this seems suspect.

I meant patient privacy which ethically important, we get fired the same as you in the US, and I brought HIPPA because you are familiar with the name, as I learned this from the US as you know I was working a Technician in my years in the US at GWUH !

 

[DrAmir0078]

I'll just assume what his attending tells him to do.

But yes, even without end tidal gas monitoring you could probably easily get away with 3-4 L flow/min and have no compromise in patient care. I mean you could just use around 2L/min if you were experienced and knew to keep the vaporizer up higher for the first 15 minutes.

I need to investigate a lot Dr. Mman !
Why we are using 7 Lt !
As I said, I need to make something, because it will save a lot of Oxygen Cylinder ! ! !

 

[daneeka]

I need to investigate a lot Dr. Mman !
Why we are using 7 Lt !
As I said, I need to make something, because it will save a lot of Oxygen Cylinder ! ! !

Hi DrAmir,

The reason you're using a high fresh gas flow (FGF) is to overcome the limitation of not using a gas analyser.

In the circle circuit on your anaesthetic machine, the ratio between recycled gas (previously expired by the patient, scrubbed of CO2 through the soda lime, and returned) versus fresh gas from (passed through the vaporiser) depends on your FGF.

So at 7L/min, almost all gas reaching the patient is fresh; at 0.5L/min almost all gas reaching the patient is recycled. You can imagine that at 0.5L/min the number on the vaporiser is nowhere near what is actually being breathed - some O2 and some volatile agent has been removed by the patient so the concentration of these drop. To complicate matters, removal of volatile agent by the patient changes as the case goes on and the patient 'fills up' with drug.

When I give an anaesthetic, I can anticipate this drop and turn my vaporiser to say 4% isoflurane, even though I only want 1% isoflurane. Then my gas analyser tells me that yes, the patient is breathing 1% isoflurane and adequate oxygen. In fact, I barely pay attention to the number on the vaporiser dial and rely on the gas analysis to tell me what the current % is.

It lets us save a lot of money not on just O2, but also the (often quite expensive) volatile agent.

Please keep in mind, if you try to do this without a gas analyser you run the risk of giving much less volatile and even oxygen than you think you're giving.

Have a look at this BJA education article for a bit more detail: Low-flow anaesthesia | Continuing Education in Anaesthesia Critical Care & Pain | Oxford Academic

 

[DrAmir0078]

Hi DrAmir,

The reason you're using a high fresh gas flow (FGF) is to overcome the limitation of not using a gas analyser.

In the circle circuit on your anaesthetic machine, the ratio between recycled gas (previously expired by the patient, scrubbed of CO2 through the soda lime, and returned) versus fresh gas from (passed through the vaporiser) depends on your FGF.

So at 7L/min, almost all gas reaching the patient is fresh; at 0.5L/min almost all gas reaching the patient is recycled. You can imagine that at 0.5L/min the number on the vaporiser is nowhere near what is actually being breathed - some O2 and some volatile agent has been removed by the patient so the concentration of these drop. To complicate matters, removal of volatile agent by the patient changes as the case goes on and the patient 'fills up' with drug.

When I give an anaesthetic, I can anticipate this drop and turn my vaporiser to say 4% isoflurane, even though I only want 1% isoflurane. Then my gas analyser tells me that yes, the patient is breathing 1% isoflurane and adequate oxygen. In fact, I barely pay attention to the number on the vaporiser dial and rely on the gas analysis to tell me what the current % is.

It lets us save a lot of money not on just O2, but also the (often quite expensive) volatile agent.

Please keep in mind, if you try to do this without a gas analyser you run the risk of giving much less volatile and even oxygen than you think you're giving.

Have a look at this BJA education article for a bit more detail: Low-flow anaesthesia | Continuing Education in Anaesthesia Critical Care & Pain | Oxford Academic

Thanks Dr. Daneeka
Our Machine, although has no Soda limes and it is closed circuit, but I am thinking recycling is not happening!
I am making a video, and will post it here as a comment or do you want me to make it separate thread to discuss the FGF?
Bare with me until uploading is done on YouTube!
I am going to read this article!
I need to know!
Thanks

 

[pgg]

Thanks Dr. Daneeka
Our Machine, although has no Soda limes and it is closed circuit, but I am thinking recycling is not happening!

At 7 LPM it's not a closed circuit; 6.5+ LPM is being vented either to the room or to the scavenging system, if one is present.

What is meant by "closed circuit" anesthesia is setting fresh gas flows to a level where ONLY metabolic oxygen consumption is supplied, and all expired CO2 is sunk into the soda lime or other absorbant. Typically flows are in the 300-500 ml/min range.

True "open circuit" would be a Mapleson setup where no gas is recycled by design (though it's important to understand that rebreathing can occur with these circuits if FGF is low).

99% of the time anesthesia machines that recirculate some gas and vent some gas and are thus semi-closed systems. Although most of us tend to run FGFs as low as possible to reduce volatile anesthetic consumption (cost), conserve heat/humidity, it's rare that anyone does true closed circuit anesthesia.

Also, true closed circuit anesthesia is a little harder to do with isoflurane because of its solubility - vaporizers need to be set very high (4%+) initially to achieve acceptable end tidal concentrations. Sevoflurane's package insert more or less precludes true closed circuit anesthesia because of its recommendations against low FGFs (compound A accumulation concerns). Desflurane is ideal.


In any case, if your machines don't have CO2 absorbant, then you're stuck using higher flows to wash out the CO2.

 

[DrAmir0078]

At 7 LPM it's not a closed circuit; 6.5+ LPM is being vented either to the room or to the scavenging system, if one is present.

What is meant by "closed circuit" anesthesia is setting fresh gas flows to a level where ONLY metabolic oxygen consumption is supplied, and all expired CO2 is sunk into the soda lime or other absorbant. Typically flows are in the 300-500 ml/min range.

True "open circuit" would be a Mapleson setup where no gas is recycled by design (though it's important to understand that rebreathing can occur with these circuits if FGF is low).

99% of the time anesthesia machines that recirculate some gas and vent some gas and are thus semi-closed systems. Although most of us tend to run FGFs as low as possible to reduce volatile anesthetic consumption (cost), conserve heat/humidity, it's rare that anyone does true closed circuit anesthesia.

Also, true closed circuit anesthesia is a little harder to do with isoflurane because of its solubility - vaporizers need to be set very high (4%+) initially to achieve acceptable end tidal concentrations. Sevoflurane's package insert more or less precludes true closed circuit anesthesia because of its recommendations against low FGFs (compound A accumulation concerns). Desflurane is ideal.


In any case, if your machines don't have CO2 absorbant, then you're stuck using higher flows to wash out the CO2.

OK Dr. pgg
So, I uploaded a video showing our Machine, so from my understanding it is not closed circuit or semiclosed!
No Soda Lime, but the canister is fixed in place, so do you think it is a rebreathing system because exhaled vases (expiration) goes to that canister and back to the patient with the Oxygen pushed to the patient through the inspiration tube!
It is a bit confusing!

 

[chocomorsel]

Is there capability for EKG? If so, why is it rarely used? It can be very valuable especially in the older patient population.

How can you tell if your patient is having any ischemia/MI under anesthesia as ischemia happens often in our field. MIs, are rare, but happen and EKG is invaluable in this regard.

BTW, Welcome OP. This is an awesome thread. Keep it coming. You are making the best situation out of limited resources.

 

[vector2]

OK Dr. pgg
So, I uploaded a video showing our Machine, so from my understanding it is not closed circuit or semiclosed!
No Soda Lime, but the canister is fixed in place, so do you think it is a rebreathing system because exhaled vases (expiration) goes to that canister and back to the patient with the Oxygen pushed to the patient through the inspiration tube!
It is a bit confusing!

I'm not sure where your video is, but ultimately the point being made is that in a circle system, total incoming or biologically produced gas flow from all sources must equal the total amount of gas flow consumed / scavenged / vented to atmosphere. Otherwise, in a closed system, high FGF (like 7L per min) would continue to keep pressurizing the system and it would pop like a balloon. Modern anesthesia machines have active scavenging systems which sequester excess gas because we have regulations on the amount of volatile anesthetic or nitrous which can be present in the OR atmosphere.

 

[DrAmir0078]

I'm not sure where your video is, but ultimately the point being made is that in a circle system, total incoming or biologically produced gas flow from all sources must equal the total amount of gas flow consumed / scavenged / vented to atmosphere. Otherwise, in a closed system, high FGF (like 7L per min) would continue to keep pressurizing the system and it would pop like a balloon. Modern anesthesia machines have active scavenging systems which sequester excess gas because we have regulations on the amount of volatile anesthetic or nitrous which can be present in the OR atmosphere.

This is the link to the new thread has a video

Our Anesthesia Machine Setting - Mysterious FGF debate!

No Soda Lime, but a scavenger system or a valve to release the excess of gasses, otherwise like what you said balloon!

 

[DrAmir0078]

Is there capability for EKG? If so, why is it rarely used? It can be very valuable especially in the older patient population.

How can you tell if your patient is having any ischemia/MI under anesthesia as ischemia happens often in our field. MIs, are rare, but happen and EKG is invaluable in this regard.

BTW, Welcome OP. This is an awesome thread. Keep it coming. You are making the best situation out of limited resources.

We have one Lead EkG monitoring, not 12 Lead in this hospital, and we can provide that for special patients!

Thanks a lot