Nitronox. Why isn't it used anymore?

[frdude1000]

We have learned about Nitronox in my AEMT class. I think the main problem is practicality (two separate bottles) as well as exposure risk. The back of an ambulance is not a well vented place...the medication is self administered and the pt. will drop the mask once they have had enough.

 

[Handsome Robb]

We have learned about Nitronox in my AEMT class. I think the main problem is practicality (two separate bottles) as well as exposure risk. The back of an ambulance is not a well vented place...the medication is self administered and the pt. will drop the mask once they have had enough.

The issue is getting the mixers.

They really aren't bad to use, plug the pigtail into your onboard o2 and have them hold the mask, turn on the exhaust fan and you're fine.

It's a demand valve mask so when they drop it it doesn't continuously flow, only when you breathe and create a vacuum in front of the mask, much like a SCBA/SCUBA mask.

 

[jwk]

Here in the Netherlands almost every ambulance carries entonox, but not everybody uses it. We are only allowed to use it outside of the ambulance. Problem is that most medics here don’t believe it works because they have tried it and it doesn’t work. My experience is that it is great to use in combination with Fentanyl. It lowers the stress levels and allows the fentanyl to work better.
I’ll use it for kids. For adults I prefer to use a combination of midazolam and esketamine if I know that I’m going to hurt them. That will knock them out just long enough to prepare them for transport. After that I use fentanyl during transport.

N2O + narcotic is approaching general anesthesia. Not really something I'd promote for use in the field. As for the idea that "it doesn't work" - well, that's either because they don't know what they're doing or their expectations are unrealistic. You cannot administer N2O and expect to get total pain relief.

 

[jwk]

It's a demand valve mask so when they drop it it doesn't continuously flow, only when you breathe and create a vacuum in front of the mask, much like a SCBA/SCUBA mask.

There is still the issue of waste gases, whether y'all want to admit it or not. We have very high air circulation rates in the OR, but we still are very concerned about waste anesthetic gases, including N2O, and our biomedical engineering guys test at least monthly for waste gas concentrations in the room.

 

[Handsome Robb]

There is still the issue of waste gases, whether y'all want to admit it or not. We have very high air circulation rates in the OR, but we still are very concerned about waste anesthetic gases, including N2O, and our biomedical engineering guys test at least monthly for waste gas concentrations in the room.

I agree it is a concern but with the windows open, the HVAC system running and the exhaust fan system running I'd be willing to bet that we circulate more air relative to the size of the room through the back of the rig than your OR.

 

[Rialaigh]

plain and simple why it isn't used in the south anymore...no real good way to keep track of it, had lots of providers huffing it every now and then for kicks.


I loved it, it's a great drug, worked great on entrapments or people who had bad femur fractures that we had to get on backboards and move. Was easy to quickly medicate them while we grabbed the rest of our equipment and that way moving them (or extricating a limb) was much less of a painful experience. Once in the bus we would get a line and give them versed with some narcotic and they wouldn't remember a thing from any of it. Seriously though, best med ever for extricating hands and arms from rollers and stuff in industrial settings.

 

[the_negro_puppy]

We used to have it and now have methoxyflurane instead.

Works reasonably well, quick to use. Works really well for injuries or pain not requiring narcs and is really good for serious pain as you can have the patient on it in 10 seconds, getting analgesia while you get iv access and push morphine which can take a few minutes.

This combined with morphine can provide high levels of analgesia, had a pt with a midshaft # femur tell me he couldn't feel his leg.

 

[jwk]

We used to have it and now have methoxyflurane instead.

Works reasonably well, quick to use. Works really well for injuries or pain not requiring narcs and is really good for serious pain as you can have the patient on it in 10 seconds, getting analgesia while you get iv access and push morphine which can take a few minutes.

This combined with morphine can provide high levels of analgesia, had a pt with a midshaft # femur tell me he couldn't feel his leg.

And you're one of the few places in the world that have it commercially available. It's not available anywhere in the US.

 

[Clare]

Entonox is a single cylinder here and we also have methoxyflurane but I've never used it, I don't understand why we have both really to be honest

 

[CANDawg]

Entonox is a single cylinder here and we also have methoxyflurane but I've never used it, I don't understand why we have both really to be honest

Single cylinder here too. Invert it a few times, hook up the mask, and away you go. It's also in our BLS scope here, which means EMTs can not have morphine but still have a pain management protocol.

 

[chaz90]

I love the concept of having some non narcotic analgesia available. Oh well, maybe one day it'll make it's way to the US.

 

[MikeCivitello]

I would agree with Robb. Working in an OR setting - with a continuous flow system is much different than what the Nitronox system is intended for and how it would be used. OR settings and dental offices use continuous flow systems - and typically for long durations. The Nitronox system is a demand flow system (gas only flows when the patient inhales) - and for short durations.

JWKs point should not be disregarded whatsoever though - there should be a concern for occupational exposure - and the operators should ensure that they do have good fresh air circulation or venting if in the back of the ambulance. In the hospital and dental settings - they should always be connected to a Vacuum source to vent the exhaled gas out of the building.

Also - with regard to occupational exposure safety - the issues of nitrous oxide use have more to do with chronic exposure day in and day out. There are small dosimeter detection badges that can be worn and submitted to testing agencies to report back 8 hour time weighted averages.


Quote:
Originally Posted by jwk
There is still the issue of waste gases, whether y'all want to admit it or not. We have very high air circulation rates in the OR, but we still are very concerned about waste anesthetic gases, including N2O, and our biomedical engineering guys test at least monthly for waste gas concentrations in the room.

I agree it is a concern but with the windows open, the HVAC system running and the exhaust fan system running I'd be willing to bet that we circulate more air relative to the size of the room through the back of the rig than your OR.

 

[MikeCivitello]

We have learned about Nitronox in my AEMT class. I think the main problem is practicality (two separate bottles) as well as exposure risk. The back of an ambulance is not a well vented place...the medication is self administered and the pt. will drop the mask once they have had enough.

Do not most ambulances have windows that can be opened and exhaust fans? Also keep in mind - it is not a continous flow where added concerns would be if the patient removes the mask from their face or drops it. The valve is closed until the patient inhales and then closes again when they stop inhaling.

On practicality - all you are connecting is a hose with quick connect to your existing oxygen source. The Nitronox system has a small cylinder of N20 (about a 20-30 minute supply) already connected to it. To start using the system - connect to oxgyen, turn the N20 valve to open, and hand the mask to the patient.

 

[Carlos Danger]

I agree it is a concern but with the windows open, the HVAC system running and the exhaust fan system running I'd be willing to bet that we circulate more air relative to the size of the room through the back of the rig than your OR.

In the OR, the anesthesia circuits scavenge 99% of the gas that the patient exhales, whereas in the ambulance, it is all exhaled directly into the cabin. So even if the ambulance does have better air circulation than the OR, there will be far more gas circulating in the cabin of the ambulance than there is in the OR.

in addition, the ambulance cabin is a lot less square footage than most OR's, meaning the potential exists for much higher gas concentrations.

I assume that as long as the exhaust fans are working properly there would be no issue, but IME, exhaust fans are one of those items that are often neglected and poorly maintained.

At the implementation of a nitrous protocol, it would be wise to have the ambulances checked at the highest flows you'll use, to be sure that concentrations don't exceed the 50ppm standard, and also make sure that the fans are continually maintained. If it's not already required by state law.

 

[Rialaigh]

I'm fairly certain it is not an issue of exposure. I know down here in the southeast it was an issue of provider usage and abusage (that rhymes..hehe..) that led to it being taken off the ambulances. There is no way to regulate amount used. If I am not mistaken there was an ambulance crash where it was determined both providers were nicely buzzed that resulted in the death of someone.

It's a medication that has abusable potential with no easy way to strictly regulate usage, its not coming back in the US...

 

[JPINFV]

I would agree with Robb. Working in an OR setting - with a continuous flow system is much different than what the Nitronox system is intended for and how it would be used. OR settings and dental offices use continuous flow systems - and typically for long durations. The Nitronox system is a demand flow system (gas only flows when the patient inhales) - and for short durations.

There's a few other points in regards to OR use. the patient is intubated and in a closed loop ventilator system with the exhaust going through scrubbers on the anesthesia machine. It's also combined both with other IV medications as well as other inhaled medications since the concentration needed to obtain anesthesia is too high (50% of people will not respond to a surgical incision to a mean aveolar pressure of 104 cm H2O. The rest of the gases the hospital I rotated through for anesthesia was less than 10. Which brings me to the other big point. When used in the OR, the end tidal concentration is measured the same way as CO2 is measured.

 

[jwk]

There's a few other points in regards to OR use. the patient is intubated and in a closed loop ventilator system with the exhaust going through scrubbers on the anesthesia machine. It's also combined both with other IV medications as well as other inhaled medications since the concentration needed to obtain anesthesia is too high (50% of people will not respond to a surgical incision to a mean aveolar pressure of 104 cm H2O. The rest of the gases the hospital I rotated through for anesthesia was less than 10. Which brings me to the other big point. When used in the OR, the end tidal concentration is measured the same way as CO2 is measured.

Most modern anesthesia systems are semi-closed, not closed. Believe it or not, there is a big difference between the two.

We use CO2 absorbers that remove CO2 only - O2, N2O, and anesthetic vapors are recirculated.

The 50% not responding to a surgical stimulus is MAC, for minimum alveolar concentration. MAC is measured in percent of expired gas, and the easiest way to think of it is as an ED50. That's why N2O alone is not capable of producing a surgical level of anesthesia, since 104% N2O is not physically possible.

EtCO2 is routinely measured in mmHg, and although most monitors have the capability to change the units, mmHg is the standard. N2O is expressed in % because it is mixed in specific ratios with other gases, although again, some monitors are able to change the units. I've never seen anyone use any other measurement for N2O - it would be far too confusing.

Not trying to be too picky, but units of measure are critically important.

 

[JPINFV]

Sorry... minimum... brain fart on the medium vs minimum and the units.

No worries on being picky either... tis important.

I've only seen N2O used either near the end of cases since it's breathed off much quicker than sevo, or as a quick boost. However the vast majority of cases at the hospital I rotated through was ran using sevo, or rarely des.

 

[Handsome Robb]

In the OR, the anesthesia circuits scavenge 99% of the gas that the patient exhales, whereas in the ambulance, it is all exhaled directly into the cabin. So even if the ambulance does have better air circulation than the OR, there will be far more gas circulating in the cabin of the ambulance than there is in the OR.

in addition, the ambulance cabin is a lot less square footage than most OR's, meaning the potential exists for much higher gas concentrations.

I assume that as long as the exhaust fans are working properly there would be no issue, but IME, exhaust fans are one of those items that are often neglected and poorly maintained.

At the implementation of a nitrous protocol, it would be wise to have the ambulances checked at the highest flows you'll use, to be sure that concentrations don't exceed the 50ppm standard, and also make sure that the fans are continually maintained. If it's not already required by state law.

You bring up good points.

My only real argument against it is we've had nitronox on the units for some time up until the last few years when we couldn't get parts and I work for a reputable company and in my experience the address issues that are similar to the ones you bring up as far as using it in the units.

I'm interested to see if it comes back now that a system is again readily available. We still have the protocol for it. I generally will "bum" it off our ALS ski patrollers while we're still on scene picking a patient up from them while we work on an IV and get some fentanyl or morphine on board, works like a dream especially in kids. Our MD is huge on pain management. I might have to bring this to his attention.

 

[MikeCivitello]

There's a few other points in regards to OR use. the patient is intubated and in a closed loop ventilator system with the exhaust going through scrubbers on the anesthesia machine. It's also combined both with other IV medications as well as other inhaled medications since the concentration needed to obtain anesthesia is too high (50% of people will not respond to a surgical incision to a mean aveolar pressure of 104 cm H2O. The rest of the gases the hospital I rotated through for anesthesia was less than 10. Which brings me to the other big point. When used in the OR, the end tidal concentration is measured the same way as CO2 is measured.

I should have been more specific in my post - I typed one thing and was thinking something else!

None of our nitrous oxide and oxygen systems are used the OR. Outside of dental (and other private practice specialties) our systems are typically used in Emergency Departments, Radiology, and Oncology - where they are doing procedural sedations with nitrous oxide and oxygen. Procedures that 15-30 minutes in length. Patients are not intubated and conscious. Our systems are intended for pain management and minimal to moderate sedation. Administration is often done with a full facemask - but some still use the dental nasal hoods.