 Courtesy photo Smiths Medical Oxy-PEEP |
Many EMS providers have recently started using Constant or Continuous Positive Airway Pressure (CPAP) therapy. Also referred to as non-invasive ventilation, these devices have reduced the need for intubation in patients experiencing congestive heart failure (CHF).
CPAP devices are an effective therapy for patients with compromised alveoli. During the inspiratory phase of respiration, oxygen-rich gas is supplied at flow rates high enough to increase airway pressure. During the expiratory phase, the patient exhales against a resistance called Positive End Expiratory Pressure (PEEP). The combination of positive inspiratory and positive expiratory pressure can help reduce the work of breathing and improve alveolar gas exchange.
Patients who receive CPAP in the field often show remarkable improvement quickly. Many providers using CPAP have reported that they intubate far fewer of their CHF and acute respiratory patients. This reduces the duration and complications from a long hospital stay. Here are the different types of CPAP devices and some of the more popular models designed for EMS use.
CPAP device types
There are basically four different types of EMS CPAP devices. The first type for EMS is the Downs Flow Generator. Two different manufacturers offer Downs Flow Generators: Respironics, showcasing three models Vital-Signs offering two. Both manufacturers have Fixed Flow and Adjustable Flow Models. The generator is a simple and rugged device that attaches directly to your portable oxygen regulator’s high-pressure port. They combine a Venturi valve and an expansion chamber for generating high, constant flow rates of ventilation gas. The disposable CPAP set combines a large bore oxygen hose and a facemask with PEEP valve.
The second type is the newer Demand Flow CPAP device. The Emergent PortO2Vent is the only stand-alone demand CPAP device available today. It provides oxygen flow only while the patient inspires, resulting in reduced gas consumption and improved respiratory monitoring. The PortO2 has an integrated PEEP mechanism with a pressure manometer for conveniently adjustable pressure therapy using a single control knob. It also features automatic mask leak compensation and uses a disposable circuit with one of the best facemasks on the market.
The third type is the Transport Ventilator with an integrated CPAP function. Several of the newer EMS ventilators offer CPAP built in. The latest one to hit the market is the AutoVent 4000 from Allied Healthcare. Other EMS/Transport Ventilators with CPAP are the Draeger Medical Oxylog 3000, the Uni-Vent Eagle 754 from Impact Instrumentation, the CareVent ALS+ from O-TWO Systems, and the pNeuton Ventilator from Airon. Any of these devices offer the superior control of time-cycled, volume-constant, mandatory ventilation WITH the ability to help people breath better BEFORE they stop.
The latest product to hit the market is the “disposable CPAP.” I have had many questions lately about this one. There are two different devices on the market that do something very close to CPAP. They can benefit many of the same patients who would benefit from CPAP or BiPAP therapy.
 Courtesy photo The Boussignac CPAP |
The Boussignac CPAP is a respiratory aid device for patients breathing spontaneously. This system is permanently open. Pressure is generated by the injection of gases passing through micro-capillaries (located all around the CPAP device) increasing in speed and generating turbulence therefore creating a “virtual valve.” Smiths Medical Oxy-PEEP is a high concentration, high flow oxygen diluter with adjustable PEEP. This unique system allows for variable flows, variable O2 concentrations and variable PEEP, all in a pre-packaged kit suitable for the ambulance.
Both devices deliver oxygen with PEEP. Neither actually supports constant or continuously positive pressure during inspiration (the “C” in “CPAP”). When the patient inhales, they get supplemental oxygen; when they exhale, they receive PEEP. With a real CPAP machine, the airway pressures remain positive during both inspiration and expiration.
These new products do have one definite advantage over more traditional CPAP therapy -- they can really speed up turnaround times. You just switch the patient over to wall outlet O2 and leave. You don’t have to wait for the on-call respiratory therapist to come down with the CPAP or Bi-PAP machine. They offer EMS providers a valuable treatment option with simple operation, without the capital expense of a pneumatic CPAP device.
There are several different ways for EMS agencies to deliver CPAP therapy in the field. Studies have demonstrated that CPAP can reduce the number of CHF patients that need to be intubated. It is the most rapidly growing new technology in EMS right now, and with very good reason. I’ve heard medics say that using a CPAP device is one of the most fun things to do on the street besides give Narcan. It’s that good.
