Pre-Hospital CPAP

Many EMS providers are starting to look at pre-hospital CPAP. CPAP stands for Constant Positive Airway Pressure. The best way to describe it is that you place a resistance against patient exhalation to increase pressure inside the lung causing more alveoli to open up and exchange gas. This can be critical when patients have many of their alveoli compromised; exactly the problem when fluid backs up in the lungs to due Congestive Heart Failure. This is usually accomplished through use of a PEEP valve, or Positive End Expiratory Pressure valve, used in combination with high flow oxygen support for the inspiratory phase of respiration..

Patients who receive CPAP in combination with drug therapy in the field often show remarkable improvement quickly. Several agencies have reported that using CPAP, they don’t have to do as many endotracheal intubations.

What is even better is that patients who have had CPAP administered in the field are likely to stay in the hospital fewer days. They don’t have to be weaned off a ventilator because they were never on one. This could dramatically cut the acute care costs for these patients.

I’m been asked a lot lately about what types of CPAP devices are out there which are suitable for EMS use. In response to these questions I would like to share;

My short primer on EMS CPAP technology. 

There are currently 3 brands of CPAP devices on the market, in two basic styles. The Caradyne device called the Whisperflow, is owned by Respironics, which is a simple Downs Flow Generator. They make these in two models; one is called a Fixed Flow device which offers no adjustments and provides about 30% Oxygen. The reduced oxygen concentration extends use time because with these Downs Flow type devices, oxygen is consumed very quickly. CPAP devices operate at flows near 100LPM, and a device of this type can burn a D tank in 4 minutes at 100%. The second Adjustable Flow model, offers adjustable flow and FIO2. Unfortunately, you really do not have any way to assess the effectiveness of a given setting.

The second device is made by Vital Signs. It is also available in two models. One is called a Downs Fixed Flow Generator, the other the Downs Adjustable Flow Generator. Both models operate the same way and are virtually identical to the two Caradyne models. The only real difference is the Vital Signs units have a round body and the Caradyne units have a square body.

All 4 of these Downs Flow devices use a CPAP mask assembly that relies on a fixed PEEP valve on the mask. Usually most use 10cm, to start. None offer a pressure gauge to assess proper function of the disposable PEEP valve. All make a lot of noise, particularly in comparison to the third device described below. They also by comparison increase the work of breathing. As most of you know from experience, the CHF patients that wind up needing an ET tube are just plain tuckered out.

The third device is about 2 decades newer in design. Emergent makes the PortOVent CPAPos. This device only flows oxygen during the inspiratory phase; so even at 100% oxygen (which most protocols call for) it uses less oxygen, and reduces the work of breathing. It is also much less noisy. The Emergent device has a better mask, an internal adjustable PEEP valve, and an integrated pressure gauge. There is also a single pressure control knob that in conjunction with the pressure gauge permits carefully titrated application. It is a little more expensive, but you get what you pay for.

One issue that sometimes comes up is size. The Downs Flow devices are much smaller than the Emergent, but this is somewhat misleading. The majority of the bulk you carry is the high-pressure oxygen supply hose and the large CPAP set (mask, hose, and PEEP if required). The reality is all five units are nearly the same size, deployment wise, with the larger Emergent PortOVent CPAP device a few square inches larger and a few ounces heavier.

To sum it up, it looks like CPAP is ready for prime time. The number of CHF patients is increasing. EMS providers are now looking at adding this treatment modality to their protocols. As with any new technology, it is of paramount importance to get familiar with all of the available options.

UPDATE on What’s New in CPAP for 09


About Dan White

I'm a retired Paramedic and EMS Instructor with 35 years EMS and emergency medical product experience. I love canoes, cars and EMS. I have written a lot about EMS Technology on the Paramedic Blog, the Insights on Innovation column for, on and I can be reached directly at 573-240-0002.
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3 Responses to Pre-Hospital CPAP

  1. Unknown says:

    Greetings To all, As of January 1st 2006 NYC EMS has approved CPAP under standing orders for Acute Pulmonry Edema/CHF. Our agency has a few CLI\’s, we and the medical directors from several EMS agencies are being trained by the manuafactuer on it\’s proper use. We in turn will train all the 911 field medics though mandatory in service. We should roll them out shortly there after. I for one am looking forward to the possitive impact it can have on the patients as well as becoming the new EMS standard or care. I still wouldlike to see Combi tubes as alternate/secondary airways in NYC. However that will be a long time coming. Stay Safe Anthony Gorman NREMT-P, CLIREMAC Paramedic

  2. Eric says:

    My agency is in the process of evaluating CPAP.  We currently are looking at the Whisperflow (30% FIo2) and the new Boussignac systems.  We are looking really hard at the WhisperFlow, and I was wondering your thoughts on the Boussignac. 

  3. Dan says:

    The Boussignac system works, and is one of
    3 non-traditional ways to deliver something very close to CPAP in a single use
    disposable. The biggest advantage of these devices (Boussignac, DHD EZ-PAP, and
    also DHD Oxy-PEEP) is that when you get to the ER, you don\’t have to wait for
    an RT to come down. You just put them on a wall flowmeter and go. The biggest
    disadvantages are the Price (all at 55-65$ per use), and the imprecise nature
    of the delivered therapy. None include a pressure manometer – if you want to
    know what you are doing to the patient you will need to add a disposable manometer
    (another 6-8$). None can deliver true 100% oxygen, because at a high-inspired
    flow rate like 60-90 LPM, the devices must dilute to work (Flowmeters only go up
    to 25LPM, right?) The Oxy-PEEP delivers the highest FIO2 of these disposable systems, and has had good reports
    from folks I trust in the field. The Boussignac system is very similar to the
    DHD EZ-PAP, only better. I enjoyed meeting Dr. Boussignac in person at EMS Today
    and really admire his ingenuity. I like his CPR Tube design even more. The one CPAP you did
    not ask about is the one I like the best.

    The Emergent Port02Vent is far better than anything else –
    it has a built in pressure gauge, can deliver 100% oxygen at a high flow rate
    of up to 100LPM. It also uses far less oxygen than any other true CPAP system,
    and is a lot less noisy (these patients are already pretty scared). It has infinitely
    variable PEEP control, which allows you to titrate to effect carefully and
    gradually. It also allows you to do nebulizer treatments inline at a low PEEP
    pressure of 2-5cm, for rapid drug absorption on COPD patients. They have a very
    cool deal available right now, which can make acquiring the best CPAP device on
    the market very affordable. Their per use cost is very low compared to other
    devices (36-38$), which is about the same as a much older designed Flow
    Generator like the Whisperflow costs to use.

    The above are my personal and biased opinions. But
    I\’ve been involved in EMS ventilation technology since 1978, and spent 6 months
    learning about everything in the world that does CPAP before I formed this
    opinion. Send me a private e-mail at my e-mail link & I\’ll let you know how
    you can get the best CPAP for the least money :>)

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