As resuscitation skills go, ventilation with a bag-valve mask is among the most fundamental â but that doesnât mean itâs easy. Rescuers have to worry about airway patency, mask seal, and also attaining the right volume, rate and pressure. Deliver too much air too fast, and you risk hyperventilation, which can . When too much air volume enters the lungs, they expand like a balloon, ultimately taking up space the heart needs to fill with blood. Other complications include regurgitation and aspiration of stomach contents due to insufflation. This could mean worsened patient outcomes, up to and including increased mortality.
The risk was first documented some time ago. A study by top cardiac docs back in 2004 found âDespite seemingly adequate training, professional rescuers consistently hyperventilated patients during out-of-hospital CPR.â1 Subsequent pig studies showed overventilation significantly decreased coronary perfusion pressures and survival rates. Ten years later French investigators used ultrasound to discover gastric insufflation rates that in some cases approached 60% during pressure-controlled facemask ventilation of hospital patients.2 French docs two years later concluded, âHealth care professionals tend to cause hyperventilation with current devices.â3
Faced with this recognized shortcoming in emergency caregiver performance, Bobbi Sue McCollum had a reasonable question: What should we do about it?
McCollum, an emergency nurse in the Portland, Oregon area, asked that of an instructor at an ACLS renewal class whoâd outlined the issue. The answer she got was less than satisfying: âStop doing it.â
âI just couldnât even fathom that we could be accidentally killing people we were trying to save,â McCollum said. âThen youâre sitting in a dark room, wondering, âHave I ever done that?â And then your second question is, âWell, what are we going to do to make it stop?ââ
McCollum was the right person to ponder the predicament. Handy, creative and interested in finding solutions since a fifth-grade invention convention, she turned the challenge over in her head on the drive home. By the time she got there, sheâd had an idea.
A SOLUTION THAT COUNTERS HUMAN TENDENCIES
Hyperventilation, McCollum understood, is a product of adrenaline and time dilation â the sensation where things seem to slow down at critical moments, such as when a crashing patient needs resuscitation. âA moment really feels like a minute when someoneâs dying,â she said. âSo the idea that anyone could accurately count things out consistently with all these other things happening around them is absurd.â
Any solution would have to counter these human tendencies. McCollum went home and took apart a BVM to ensure she understood its physics. Convinced her idea would work, she headed to the craft store. The first challenge was to create a plastic valve that would control the bagâs refill time.
She found a material used by sculptors to make molds, then used strips of foam to build approximations of the parts she needed and created one. Pouring resin into that mold created a workable part she then mounted back onto the disassembled BVM.
The second part â a mechanism to control volume output by squeezing the bag in various ways â was more challenging. McCollum rigged up a complex system of beakers and tubes to test the volume output when the bag was compressed at various points. That ultimately led to a cover for the body of the bag that featured compression-point tabs to help standardize volume output.
âI understood I needed the bag to tell me when to squeeze it, but I couldnât be required to look at the bag,â she explained. âWhen you have a patient, youâre not staring at your equipment â youâre watching your patient. Youâre also supposed to be looking for chest rise and making sure you have a mask seal and are discussing the next steps in your care. Too many things are happening. I knew if I could just feel when it was time to squeeze, I could still participate in all those other things.â
Marking the bag to control volume delivery and restricting rate with a control valve that delayed the bagâs refill solved both challenges. McCollum called her product the Goldilocks Valve, because it represented rescue breathing âdone just right.â
The operational difference for providers is squeezing the bag until your fingers touch â something not done with traditional BVMs, where it would deliver too much air.
âThatâs the tactical cue,â she added. âYou have the compression points and squeeze till your fingers touch, and then the valve delays the refill for the appropriate amount of time. So when itâs totally reinflated, you can just feel, then you squeeze again. Thatâll give you approximately 10 breaths per minute.â
McCollum tested the result with medical students at the University of Portland, who ran mock codes using both a regular BVM and the Goldilocks Valve. âThere was a significant difference in the rates and volumes given,â she said. âWe were able to show its efficacy, and that was just with our prototype.â
A BIG BET PAYS OFF
Nonetheless, McCollum had trouble getting the device to market. While a legitimate risk, hyperventilation in emergency care isnât easily understood by lay people or on many folksâ minds. No big-money funders showed initial interest in the idea.
Without immediate traction, debt was mounting on the fledgling project, for which McCollumâs husband had cashed in his retirement. Then her best friend, Sara Halmes, stepped in with an offer to bankroll the creation of a company to produce Goldilocks Valves. âI told her, âSara, thatâs a terrible plan,ââ McCollum recalled. ââYouâre breaking all the rules. Youâre not supposed to mix money and friends.ââ
She did anyway. Halmesâ investment funded early 3D printing of the valves, but initial efforts lacked the needed precision. However, with the help of McCollumâs sister-in-law, Zelda English, McCollum and Halmes had meanwhile produced a video to help generate interest in their project. That came to the attention of producers in Hollywood, who invited them to compete on a reality show aimed at helping inventors overcome the obstacles holding them back.
They didnât win the show â but it provided them their first true working prototype. âBecause of that, we had a working process,â McCollum said.
More rejections followed, though, from both investors and potential manufacturers. Bank balances dwindled. The quest began to look dire. McCollum started to contend with the prospect that hers might be another great EMS idea left unrealized.
Finally a paramedic friend, Jeff Birrer, suggested a Hail Mary trip to EMS World Expo â the industryâs largest trade show and educational conference. It was in Las Vegas that year â an affordable flight. They couldnât afford a booth, but getting onto the exhibit hall floor would cost $35 â which was exactly what was left in the businessâ reserves.
McCollum bet her last $35 and went in â and spun triple sevens. She found a small business that loved the idea but couldnât make it happen. But they introduced her to representatives from . Pulmodyne leaders were aware of the Goldilocks Valve and very interested in it. The company obtained its rights, and itâs now offered as its .
A NEW STANDARD OF CARE?
Still using McCollumâs tactile feedback approach, the is a manual resuscitator that reliably delivers the 10 500â600-milliliter breaths per minute recommended by the American Heart Association for average adults. The control valve restricts refill of the bag to around four seconds, helping limit the frequency of squeezes, and at 1,200 milliliters the bag itself is smaller than most adult bags, helping control the volume of air delivered. Users simply squeeze the bag, pressing their thumb and fingers together using the ridges. When the control valve isnât activated, the device functions as a traditional unrestricted BVM. The VT Select comes with an optional PEEP valve, filter and dial manometer.
The VT Select can now be seen throughout EMS and fire departments, including the FD serving McCollumâs suburban town. Feedback has been positive. In one anecdote, a New York police officer was asked to bag for a shorthanded crew and balked, afraid heâd mess up. In under a minute, the EMS crew showed him how to use the VT Select, and he assisted them successfully.
With stories like that, McCollum hopes the solution â simple, low-tech and low-cost â can help improve this common but suboptimal prehospital practice.
âI get that Iâm the most biased person you can ask,â she said. âBut realistically, just fully understanding the challenge, this is such a simple solution, I think it could easily change the standard of care.
âWe have something that can stop this problem now â thereâs no reason not to use it. I mean, I donât have to have the worldâs best-selling medical device. At the end of the day, I just donât want to hurt anyone.â
REFERENCES
1. âDeath by hyperventilation: A common and life-threatening problem during cardiopulmonary resuscitation.â Tom P. Aufderheide, Keith G. Lurie. Critical Care Medicine. Sep 2004.
2. âReal-time detection of gastric insufflation related to facemask pressure-controlled ventilation using ultrasonography of the antrum and epigastric auscultation in nonparalyzed patients: a prospective, randomized, double-blind study.â Lionel Bouvet, Marie-Laure Albert, Caroline Augris, et al. Anesthesiology. 2014.
3. âEvaluation of bag-valve-mask ventilation in manikin studies: What are the current limitations?â Abdo Khoury, Fatimata Seydou Sall, Alban De Luca, et al. BioMed Research International. May 2016.
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