Rise of the CPR Machines

Red Blood Cells

The latest device to be added to the EMS provider’s arsenal is the Automated CPR machine. They are meant to be attached to a patient in Cardiac Arrest in order to provide un-interrupted compressions for as long as the device is operating. The primary justification for their use is that they will provide perfect compressions each and every time, something even the best provider is unable to do, primarily due to fatigue. In addition, the use of the machine frees up the crew, allowing them to begin other procedures, ventilate, or simply remain seated during the ambulance ride. Do these machines actually work? Some studies suggest that they do, such as the John Hopkins study; which measured blood flow in pigs as the device was operated (link), and the The Heart Institute study (link) which measured the perfusion of human subject on whom the device was used. Both studies showed that an automated CPR device resulted in increased cardiac pressures and perfusion over manual CPR. In addition, the fringe benefits such as freeing up on-scene personnel and allowing them to remain safely seated during ambulance rides mean that an automated CPR machine is definitely a device that warrants some consideration.

There are two forerunners in automated CPR technology; the LUCAS made by Jolife, and the Autopulse made by Zoll (formerly Revivant).

Table comparing CPR machines

  The Autopulse makes use of a “Life Band”, a disposable strap that is used to constrict the patient’s entire chest. The band is a onetime use item and must be replaced after operation, at a cost of $125. The Life Band attaches to a half backboard upon which the patient lays. This board contains all the controls for the device as well as holds the battery pack.

  Also available is the LUCAS (Lund University Cardiac Arrest System), which was released in Europe in 2003 (and in the US in 2007). This arch shaped device clips into a narrow back plate and uses a single piston assembly to mimic the compression area of manual CPR. The original LUCAS was only powered by compressed air sources and used up 52 Liters/min of air while operating. The LUCAS 2 works exactly the same as the original LUCAS, only it is powered by a rechargeable battery back which will last for up to 45 minutes of operation. The device also includes a stabilization strap to further secure the device to the patient as well as two arm straps to hold the patients arms out of the way. Making use of these is recommended, but not if their deployment would delay transportation of the patient.

  As far as the EMS provider is concerned both devices could be considered identical. Yes there are some ideological differences such as whether or not the device should constrict the whole chest, as the AutoPulse does, or mimic current CPR techniques as the LUCAS does. A carefully constructed, random sample study will have to be done to prove beyond a shadow of a doubt which machine (if any) provides the best chance of an arrest victim walking out of the hospital. Currently, there is not enough data to make an accurate, real life judgment on either unit.

  As far as the EMS provider is concerned, both devices allow for un-interrupted compressions beyond the number an average human could provide. Both devices allow for hands-free CPR which will free the crew up to perform other life saving tasks, as well as keeping them safe in the back of an ambulance. No matter which machine is used, it is important that the crew receive proper instruction on its use and consistently practice, so that it can be put into use with minimal interruption. It is also important that manual CPR techniques are not forgotten, because machinery malfunctions are inevitable and manual CPR is still a proven way to get blood flowing throughout the body.

Photo Credit: Image: renjith krishnan / FreeDigitalPhotos.net

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