View Full Version : Albuterol for Emergency Tx of Premature labor?
Was reading MSF's "Essential Drugs: Practical Guidelines" and came across mention reference to the use of injectable Aluterol as an emergency tx for premature labor.
The first question that came to mind is what is premature? At what point do you have a primmy - an ICN case, that obviously not going to make it in an austere setting, and at what point is it better to just deliver the kid? 8 months? 8 1/2 months? other?
The second thought was that Albuterol inhalers are common in the population - injectable albuterol is not... so could you use an inhaler or two to the same ends...? (ditto for the nebulizer route - having the liquid drug, but lacking the IV...) This is more a question on time/dose problems to see if it's viable than anything else.
yes - there are a string of contra-indications: enclampsia/pre-enclampsia, uterine hemorrhage, uterine infection, severe cardiopathy. - so even if you have the material for the IV route, what is the best cource of action in those cases?
anyways, information I'm uncertain on or don't know:
how much total medicne is in an albuterol inhaler?
if 0.001mg = 1ug and 1.0mg = 1000ug?
(think I got that right... mg=10^-3 and ug=10^-6)
If that's the case - this is impractical... I was thinking 1.0mg=100ug originally... but still an interesting exercise. Probably.
quantity of fluid per drop in an IV, or more to the point how long it will take at a rate of 30-40 drops per minute to empty a 500-550ml IV bag. ie: at what rate is the medicine being administered, so puffs per minute could be calculated. (I'm thinking 1cc = 1 drop, but I'm not positive)
known information:
injectable (liquid) albuterol:
5ml ampoule = 0.25mg (0.05mg/ml) or
1ml ampoule = 0.5mg (0.5mg/ml) or
5ml ampoule = 5mg (1mg/ml)
Aerosol inhaler releases 100ug (0.1mg) per puff
Adult dose for asthma is 1-2 puffs (100-200ug or 0.1 - 0.2mg)
Adult IM/SC dose is 0.5mg for Asthma or
IV (slow) is 0.25mg
Can we generalize this to 2x - 2.5x IV dose = inhalation dose?
(checks w/ RQD's rule of thumb for this conversion)
But can we expand that to 2.5x - 5x the inhalation dose for IM/SC dose? - in general?
Tx for premature labor is:
5mg (looks like up to 50 puffs? - maybe this will work... well, 100 - 125 after the rule of thumb for administration route...) anyway, by infusion it's diluted in 500ml of 5% glucose OR 0.9 NaCl at about 30-40 dpm... and that rate is gradually increased until uterine contractions cease. Then the dosage is decreased.
have I got this right?
so how many puffs per minute to match the IV route?
how many puffs are in a standard albuterol container (how many containers would be needed?)
if you couldn't get a line, does that mean you could go with a matching IM/SC injection or injections (probably the latter - spaced how often and how much?)
If using the injectable med in a nubulizer for astham tx... well, same Q's... w/ average portable nebulizer rates added to confuse things...
Related is at what rate the battery powered nubulizers administer medicine...
(going the other way - for an asthma attack and using a nebulizer and liquid albuterol...)
Anyway, who wants to jump in and work out the drug calculations for altering routes of administration? (please show your calculations)
thanks,
-t
Obstetrics is clearly not my area...
http://www.aafp.org/afp/980515ap/vonderp.html This is a practical 1998 discussion of pre-term labor that seems applicable to the discussion.
Because I trained in the 1980's, ritodrine was more commonly in use, with some use of terbutaline. Ritodrine has decreased in use.
The AFP article mentions a wide variety of drugs, as well as clarifying your question about the definition of pre-term labor.
As far as your calculations go - an albuterol MDI delivers 100mcg (0.1mg), of which 90mcg makes it to the mouthpiece. There are 80 puffs in a 6.8gm canister, and 200 puffs in a 17gm cannister. We might give 0.2-0.3mg or even as much as 0.5mg albuterol via nebulizer as a single dose. So you can see that 2 puffs, or 3 puffs will be about comparable in amount to a typical nebulizer dose.
Terbutaline is also available as an inhaler. I believe depending on the country it's sold in, it comes in 200mcg or 250mcg/inhalation MDI's. A terbutaline dose for pre-term labor given SQ is 0.25mg, which is comparable to the MDI doses. The oral doses of the beta-2 agonists hare higher (more or less 10 times higher - whether for albuterol or terbutaline when used for asthma, or for terbutaline used for pre-term labor).
IOW - people do not take lots of puffs from a MDI to achieve the effects you are talking about. In that sense your calculations are headed in the direction of an overdose.
The only data I've encountered on beta-2 agonists for pre-term labor have been SQ or IV dosing - not inhaled. I did a little searching prior to posting - while it's clearly not exhaustive, it didn't turn up anything on inhaled beta-2 agonists intentionally being used for pre-term labor. What came up were package insert concerns about the *potential* to interfere with labor progressing if a woman inhales such an agent - based on the data with IV administration at effective doses for pre-term labor.
If you (or other members) turn up references on inhaled beta-2 agonists for pre-term labor, please post them.
As far as improvising goes, there are a number of agents which have an effect on pre-term labor mentioned in the AFP article - quite a variety of classes of medications. I'd also point out the information it includes on fetal survival and corticosteroid therapy. Assuming that's still as valid as it was in 1998, that would be worthwhile to consider - perhaps as much or more so than efforts to stop labor. It also emphasizes preventing pre-term labor - which gets into pre-natal care, and inevitably brings up elements of laboratory medicine.
It's been more than 20 years since I heard a vigorous discussion of using an alcohol drip for pre-term labor.
As far as the meds discussed in the AFP article, as I ponder what I'd likely have available among my top 10 or top 20 drugs to cover a widest variety of needs, I come back to corticosteroids. Particularly if I only had those 10 or so drugs.
EEEK! sounds like I got it right (or was closer) the first time. Was unsure, so asked one of my roomies (PhD candidate in math). Went with his solution and am ending up w/ egg on my face... - won't do THAT again...
> The oral doses of the beta-2 agonists hare higher (more or less 10 times higher - whether for albuterol or terbutaline when used for asthma, or for terbutaline used for pre-term labor).
That much? RQD's rule for inhalation is x2.5... does that extend to all drugs? When I think "oral" I'm thinking swallow. That's a lot different than "inhale"...
> It's been more than 20 years since I heard a vigorous discussion of using an alcohol drip for pre-term labor.
please say more!!! - you seem to be implying that getting 750mL of vodka into mom's gullet might just do the trick... (well - that would probably be an OD too...)
Only thing I've heard an ETOH drip used for was pollyethalene(sp?) ie: antifreeze poisoning...
> As far as the meds discussed in the AFP article, as I ponder what I'd likely have available among my top 10 or top 20 drugs to cover a widest variety of needs, I come back to corticosteroids. Particularly if I only had those 10 or so drugs.
which one are you thinking of in particular? (and what are the other 9-19?)
Thanks for the informative and thoughtful reply! Sorry it's taken so long to get back to you.
btw: "lab medicine" - why? - what?
thanks,
-t
ps: I was a bit shocked to find that "pre-term" was considered 9mo or less. (allways thought 9mo was the norm, not 9mo and 1 week...) Still, it's been a long time since I was around ICN nurses, but our premies tended to be a LOT more pre-term than a week. And females are unlikely to be able to pinpoint the exact DAY they got pregnant, as opposed to the delivery day. A 1 week window seems a bit short for being "early"...
That much? RQD's rule for inhalation is x2.5... does that extend to all drugs? When I think "oral" I'm thinking swallow. That's a lot different than "inhale"...
I'm not sure where you are with that, but I'm guessing you're talking about drugs used for rescucitation that are traditionally given IV. In some instances, some of these agents can be given down an endotracheal tube if you have intubated the patient but do not yet have IV access. For example - epinephrine, atropine can certainly be given endotracheally. Note - that's not even inhaling - it's more like dumping liquid into the airway and having it aspirated, and looking at how well that volume is absorbed. There's also usually a "chaser" of fluid, such as saline.
Yes - simply compare doses of tablets (albuterol, terbutaline, etc.). You'll see the miligrams compared to the inhaled doses (in 100's of micrograms).
Only thing I've heard an ETOH drip used for was pollyethalene(sp?) ie: antifreeze poisoning...
Polyethylene glycol. Actually, you can also use an alcohol drip for methanol ingestion, too.
In either case, what you're accomplishing is a delay in the body metabolizing polyethylene glycol or methanol, and giving yourself time to find a way to remove the offending polyethylene glycol or methanol (such as by dialysis). Both substances cause the most damage by being metabolized. When you read about seeing (high anion gap) metabolic acidosis with poisoning by ethylene glycol or methanol, you're talking about later in the course of the event, once metabolism has occured.
Our enzymes preferentially metabolize ethanol, so if you run an alcohol drip, you will delay metabolism of ethylene glycol or methanol.
It's not enough to do only that - you still need to get rid of the offending substances.
> As far as the meds discussed in the AFP article, as I ponder what I'd likely have available among my top 10 or top 20 drugs to cover a widest variety of needs, I come back to corticosteroids. Particularly if I only had those 10 or so drugs.
which one are you thinking of in particular?
Whichever corticosteroid I have available. If push comes to shove - take your pick, what've you got.
Again - it's not stopping pre-term labor, it's dealing with newborn survival once delivered. What you're looking at is fetal lung maturity. It improves with corticosteroids.
btw: "lab medicine" - why? - what?
I didn't follow you there.
Actually - ethylene glycol - period - just caught that. Got on a roll following your comment. Ethylene glycol is absorbed after ingestion, and then metabolized.
PEG (polyethylene glycol) is actually different, and is ingested for bowel preparation (for stuff like colonoscopy) or for control of more difficult constipation. It's not absorbed.
PEG is found in products such as miralax, as well as in bowel preps such as GoLytely, Co Lyte, etc.
Picture this if you need an association or mnemonic:
Instead of the Lite Beer commercial -- you get the 2 GI guys doing the GoLytely commercial:
TASTES GREAT!! LESS FILLING!
DB,
need to get back to you on your last 2 posts, but for now, just caught a snippit on public TV about an unidentified primate that lives in Lima and the mothers diet was high in a leaf that contains tannins...
apparently, it helps stop post partem hemoriging and prevents miscarages due to it's anti-stringent properties.
anyone run across anything like this for people??? Sounds like coffee and tea is good for moms! though they implied fairly heavy doses... maybe a useful primitive Tx if you have nothing else. For that matter why does strong coffee help in an ashma attack and would tea also (or boiled bark?)
thanks,
-t
For that matter why does strong coffee help in an ashma attack and would tea also (or boiled bark?)
Not that aminophylline/theophylline are the greatest asthma drugs around, but caffeine seems to have pretty much similar actions in the body as they do. You will no doubt find lot of pharmacology, 2nd messenger hypothesis stuff, cAMP (cyclic AMP) and so on.
The whole methylxanthine angle is treating asthma mainly by treating bronchospasm.
It pretty leaves the inflammatory component of asthma out of the picture, which is where we're seeing more asthma deaths (particularly when people keep beating away at bronchospasm as the person gets sicker and don't up the ante to deal with inflammation). There's nothing wrong with dealing with bronchospasm preventively (exercise or cold induced asthma, for example), or as it occurs, it's just not a great strategy to only treat bronchospasm with prolonged episiodes, especially in someone who is not rapidly improving.
I was at a medical staff meeting last night, and had a chance to chat with a neonatologist. I used the conversation to catch up on my old/out of date recollections of neonatology.
If you get a sense that I am de-emphasizing control of pre-term labor at all dates in austere circumstances in my comments in this thread (as well as pointing out a wider variety of pharmacologic interventions than beta-2 agonists), you're correct.
I have been emphasizing new-born survival, which is also what my colleague emphasized to me last night. It's somewhat related to pre-maturity, but is also something of different topic.
My colleague also pointed out examples of times where going ahead with early delivery is desireable for mother and child -- such as severe hypertension in the mother, or addressing the higher rates of death/complications among larger babies of diabetic mothers (especially late term pregnancy).
He also pointed out that L/S ratios are being used less often on amniotic fluid than in the past - at least for decision making about delivery. Not that L/S ratios would be available in austere conditions - but the types of thinking that involve L/S ratios could still be imagined and would be a tie-in to what I mentioned about glucocorticoids. My colleague also affirmed the use of glucocorticoids in selected instances of early delivery.
I guess I come back to suggesting that the AFP article is a good starting point, and should give some ideas for general pharmacologic interventions where it's applicable.
Oh - yeah - lest I forget...
My colleague also reminded me that there are different outcomes and abilities to influence outcomes at different dates of pregnancy (how pre-mature a delivery is), as well as why there is pre-maturity.
I guess it's one more topic where learning the principles, and having a broader "fund of knowledge" is really the need.
I'm not discouraging lay people from stepping up to the plate in austere circumstances. However, I am trying to discuss things on a level which pushes people to stretch themselves to learn. KISS approaches work well when you're able to support a patient and get them to a higher level of care somewhat quickly.
Being in a location for the forseeable future, and not having a higher level of care available means treating people in place, which imposes the demands of providing definitive care for the duration. KISS approaches unravel more often than not at some point in that episide of care.
Could some of that be addressed by telecommunication with other personnel? Perhaps.
Could that involve having a conversation that includes knowing what supplies you have in your inventory? Probably. Might that include making the best judgement available at the time given the available supplies - it's hard to imagine not doing it that way.
Realistically, would we see some pre-term labor result in babies born into austere circumstances who will have complications that will be insurmountable? Probably. Psychological support, grieving, education, community care, etc. are all needs applicable to this subject, just as they are to the scope of healthcare needs to be encountered in a prolonged austere adventure/misadventure.
What duration of course of treatment of pre-term labor is realistic to plan for? For how many patients?
Again - it comes back to knowing your group of people, their health, their ages, and so on.
It also is a good reminder that we can always care for people whether or not we have the means to treat a condition, whether or not we're successful in treating that condition.
Powered by vBulletin™ Version 4.1.3 Copyright © 2012 vBulletin Solutions, Inc. All rights reserved.