Getting the depth of chest compressions right is one measure of quality, according to a research article on this development, reports New Scientist.
And Philips' new device helps first aiders to do the same, adds the report.
The company claims that its CPR coach works by giving physical feedback to let first aiders know when the right depth has been reached - that is around 4 centimetres for an adult, and around 2.5cm for a child.
The CPR coach is a pad placed over the patient's chest that contains accelerometers to monitor compression depth.
When the right depth has been reached, the device vibrates to warn the rescuer to stop.
This can be combined with audio coaching, in the form of rhythmic beeps for a rescuer to follow.