Cite this post as:
Scott Weingart, MD FCCM. Wee – What the heck is a Mapleson B Circuit and Why You Probably Shouldn’t Care. EMCrit Blog. Published on March 11, 2014. Accessed on April 18th 2024. Available at [https://emcrit.org/emcrit/what-the-heck-is-a-mapleson-b-circuitu-probably-shouldnt-care/ ].
Financial Disclosures:
Dr. Scott Weingart, Course Director, reports no relevant financial relationships with ineligible companies.
This episode’s speaker(s), (listed above), report no relevant financial relationships with ineligible companies.
CME Review
Original Release: March 11, 2014
Date of Most Recent Review: Jan 1, 2022
Termination Date: Jan 1, 2025
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thanks for doing this Scott. saves me a lot of arguing with the Chrimestar
somehow I doubt it will save you : )
Scott your plan has worked! I don’t have time for my usual manifesto – but you’ll pay for it with a protracted verbal rant at smaac! As you know from our face-to-face discussions, our areas of agreement actually far outweigh our areas of disagreement. I will say this though. Whilst I agree 100% re 2 handed face mask technique (and the use of the “thumb grip” rather than the “classical grip”), I disagree that the benefits of the collapsible bag on the Mapleson are negated by using two hands. I also think that it’s worth delineating the issues with FMV… Read more »
can’t wait! i won’t rile you up by responding–I’ll wait to hoist a beer in person, my friend.
he keeps getting back up..
Hi Nick,
Having reasonable familiarity with both self-inflating ventilators and the Mapleson circuit I certainly can appreciate the greater tactile and visual feedback you get with the latter that I (or the patient is) achieving adequate ventilation via the mask. But from a practical viewpoint how would you alter your strategy if you felt prior to induction that you were likely to enter a can’t ‘ventilate’ scenario. Would you more likely to ‘vortex’ to LMA rather than trying a mask seal if you had trouble intubating?
best off going to Nick’s original post and commenting there, not sure if he is reading the comments here
Hey Scott, I debated a bit with Nic and Minh about this a while back, frankly I’m still somewhat on the fence. I found you kind of jumped all over the place in the wee, comparing Mapleson to BVM, NRB mask, NC and ventilators as it suited you. If you take nasal prongs and 2 hand mask seal as a given in both scenarios, the comparison between BVM and Mapleson is simpler: -Mapleson does PEEP like a vent, better than a PEEP valve. That’s why we use flow inflating bags in grunting, indrawing newborns, they just need a bit of… Read more »
Sean, I refuse to have to pick just BVM vs. NRB/NC for the simple reason that I don’t use just one. The debate Nick set up is use of mapleson B for everything vs. Rich’s and my strategy of NRB/NC unless shunt and then a PEEP-capable device. You’ve got to accept the bundle b/c that is how it is done on pts. Mapleson doesn’t do PEEP like a vent the BVM with a PEEP valve does (low-flow CPAP), in some ways the Mapleson does it better than a vent (high-flow CPAP). However, if the NC cannula is there, then all… Read more »
Don’t bring one to a code either.
1. I’ve already started preoxygenating before anesthesia gets arrives.
2. The middle of a code is not the time to introduce new equipment to the team.
I also want a peep valve on every single bm that I use you never know when that patient is going to need to peep.
Hi Scott, You know I love your podcast and look forward to hearing it. I agree with most of what you say, except on airway issues where I often disagree considerably. Case in point: your friend is correct here. The Mapleson D set-up is vastly superior to BVM and there are only two reasons not to use it for initial airway management: you don’t have one or you don’t know how to use it. I suspect in the ED the issue is both, in which case one can use a BVM with PEEP valve, although it should be of the… Read more »
Hi Scott, Being an Intensivist of anaesthetic background and having worked and trained in the UK, I enjoyed your podcast greatly. The Mapleson C and not B as suggested here is used extensively in UK in anaesthetic practice. The difference between the Mapleson C and Mapleson B is that the Mapleson C is devoid of the long tubing between the valve and the bag and therefore easier to handle than the Mapleson B. The big advantage with these is that you can see the bag move and therefore have a rough idea of the increasing tidal volume and rate. This… Read more »
fantastic comment. you will however see the BVM bag moving with spont resps, just as you do with the Mapleson–for both of them of course, this is reliant on a tight mask seal
Hi Nick,
Having reasonable familiarity with both self-inflating ventilators and the Mapleson circuit I certainly can appreciate the greater tactile and visual feedback you get with the latter that I (or the patient is) achieving adequate ventilation via the mask. But from a practical viewpoint how would you alter your strategy if you felt prior to induction that you were likely to enter a can’t ‘ventilate’ scenario. Would you more likely to ‘vortex’ to LMA rather than trying a mask seal if you had trouble intubating?
Great post Just a note – the animation above depicts a Mapleson A not Mapleson B (where the FGF should enter after the corrugated tubing near the patient.) – I usually anaesthetise in theatre and will therefore use either the ventilator (plus or minus cpap/pressure support + CPAP if required) or a variant on mapleson A the parallel lack system (http://www.frca.co.uk/images_main/resources/Intersurgical/lack.jpg), why this doesnt exist with simple one way inspiratory / expiratory flutter valve down each limb I dont know as this would massively reduce the required FGF to prevent rebreathing of dead space gas for SV or IPPV. As… Read more »
thought all of these were specifically designed for rebreathing to save on volatile gas costs, is this not the case?
I am in support of a BVM with NC + Peep Valve….i work in ED..but when i was in Anaesthetics, using a mapleson with a relaxed time controlled environment was excellent and trains you to understand lung compliance and improves use hand masking…However, i cannot even remember the last time i was in ed, with a crashing patient who i had the luxury of time with. Usually on night shifts, I’m intubating and running the resus as well so the chances of me being able to perfectly face mask bag my patients is prob not very high.id like all the… Read more »