There are currently four different ways to deliver CPAP in the field:
1. The Downs Flow Generator – The Downs Flow Generator is the original CPAP machine. There are currently two distinct types of Downs Flow device, the Adjustable Flow and the Fixed Flow. They are simple and rugged devices featuring a DISS input, round or square shaped expansion chamber, venturi air entrainment port, and circuit connection.
The expiratory phase is controlled separately at the patient mask with a PEEP valve. The non-adjustable type PEEP valves work better than adjustable PEEP valves, but make it less convenient and more expensive to adjust pressure. The latest version of the Adjustable Downs Flow type CPAP is the new FloPAPP from Flotec, Inc. The FloPAPP features adjustable aspiratory flow rates and an adjustable PEEP valve on the mask. This allows the clinician to slowly increase PEEP pressure to protocol-based pressure objective or patient tolerance. With adjustable inspiratory flows, you can also better match the flow rate to the patient’s inspiratory drive (I also really like the compact disposable patient circuit).
2. Demand-Flow – There are currently two demand-flow types of CPAPs on the market: the Emergent PortO2Vent and the Airon MACS CPAP. Both of these high-quality devices provide infinitely variable PEEP, a built-in pressure gauge, and they only flow oxygen during inspiration, for reduced oxygen consumption and easier patient monitoring.
3. Ventilator with CPAP functionality – These are several great devices on the market, including the LSP AutoVent 4000, CareVent ALS+, Impact’s 754 and new 731, and the Draeger Oxylog 3000. A few can deliver either CPAP or BiPAP at the preference of the physician. Most have advanced respiratory monitoring capabilities well beyond those found on the other types of EMS CPAP devices. And they can all serve at least three different roles: work as a CPAP, provide controlled mandatory ventilation for emergency patients, and or work during patient transports as a ventilator.
4. Disposable – The Boussignac CPAP device is an oxygen-powered disposable PEEP valve and mask assembly. It provides expiratory pressure support generated by the flow of oxygen from a standard regulated oxygen source. It also provides some oxygen enrichment; however, since PEEP is tied to oxygen flow rate, it cannot deliver low PEEP at high FIO2. The only other drawback is that is does not provide Inspiratory Pressure Support, the other half of what makes CPAP beneficial. Another disposable option is the Smith Oxy-PEEP. This product features a variable FIO2 venturi, non-rebreathing bag, and variable PEEP valve. It can provide low PEEP and high FIO2 simultaneously, but it also does not support inspiration with positive airway pressure. The latest disposable CPAP device worth noting is the new O2ResQ. The O2ResQ is a true disposable CPAP of the fixed Downs Flow type. It’s very simple and easy to use; it uses an innovative plastic expansion chamber with venturi air entrainment port, and offers different threshold resistor style PEEP valves.
CPAP has really come of age in EMS. Once all we had was the choice between an oxygen mask and an ET tube. In medic school we learned a lot about how to breathe for patients that cannot breathe on their own. For the first time, CPAP gives us a practical tool for helping patients ventilate better before they stop breathing. Over half the EMS agencies that could use CPAP under their state protocols now do. If your agency is not among them, it’s time you took another look.