Why Isn't Nitrous Oxide Widely Available for Labor Pain Relief in the U.S.?

My understanding is that Nitrous Oxide is considered a workplace safety hazard for dental hygienists and others who are around it a lot:

http://www.cdc.gov/niosh/nitoxide.html

Maybe US hospitals would say that using nitrous in labor posed too much hazard to their employees?

Penny, you raise an interesting point, as there does seem to be a fair bit of debate in the literature about the occupational safety of the gas, and interest in using scavenging systems in dental office and hospitals that would reduce occupational exposure. Those discussions don't seem to address the lack of availability for obstetrics patients in the first place, though.

Great post! I have wondered that myself. Two midwifery students from England did a short stint at the birth center where i trained, and they were very surprised that we didn't use it. As far as we can figure out, there is no state health code against it, and the midwives briefly toyed with the idea of bringing it in. But, the state health code does prohibit birth centers for providing certain types of labor analgesia, so that may prohibit nitrous oxide, also. They didn't want to push it.

This is only a guess, but I suspect the issue might be liability. Have their been controlled clinic studies? If not, probably folks are afraid of being sued.

Based on how I felt when laughing gas was used at the dentist's, I felt too "loopy", for lack of better word, not exactly the state of mind I want to be when I meet my child for the first time. I agree, though, let's see some more research on this.

An anesthesiologist I know has this response:

Nitrous oxide in trace amounts is considered a biological hazard. It must be scavenged, which is difficult to impossible for someone who has just been taught to self-administer while in labor.

In a study in the 1970s, chair-side dental assistants in offices where N2O was used had higher rates of spontaneous abortion than assistants in dental
offices where N20 was not used. That was probably why N2O disappeared in the US by the end of that decade.

There is a tremendous abuse potential for N20, and perhaps other countries do not seek to control access, but the US does. Dentists often abuse N2O, resulting in neuropathy. N2O cylinders sitting around would be likely to be abused.

Nitrous can be administered in a "safe" 50% mixture with O2, but the results can be highly variable and are unpredictable. Some patients get little relief,
while the same inhaled concentration could render others unconscious. Disinhibition regularly occurs (it was described in the demonstration that gave W.T.G. Morton, one of the founders of surgical anesthesia, the idea) and can lead to dangerous behavior, such as excitation and pulling out IVs. People can have
amnesia from N2O; while receiving it they can be screaming in pain, but later not remember. The patients and nurses at my hospital would not accept what N2O
has to offer.

A properly done labor epidural allows the mother to be fully sentient with well controlled pain and the ability to cooperate. N2O has some analgesic properties, but they only come with a clouding of the sensorium and risks such as combativeness, loss of consciousness, and pulmonary aspiration.

If one wants analgesia free of risks of inhaled vapors, one can use injections of demerol, morphine, etc. These make the baby a little sleepier, but not critically so unless used in large and repeated doses.

Rachel: Occupational question here.

Do you have any idea if it's being used in Europe for abortions, and if so, know of anywhere I can look for studies/info on that one?

Mind, all of the %$#@!! laws flopped on providers here to make it difficult for us to provide them may still mean we can't use it for that, but it seems like it'd be a pretty excellent option, if not, and if it's worked elsewhere.

Heather, that's a great question, and one I don't know the answer to off the top of my head, although I'll see what I can find. I would normally recommend EMBASE as a starting point and some double-checking in PubMed for this question, but EMBASE is subscription-only. I'll take a look.