Mechanical chest compression devices for CPR

Mechanical chest compression devices for CPR

Conventionally cardiopulmonary resuscitation (CPR) is done by manual chest compressions, with operators rotating to avoid fatigue. Automatic machines have been developed using pistons, pneumatic vests and band like mechanisms to take over the tiring work of chest compressions which is the most demanding part of CPR, especially when it is prolonged. Theoretically they can be better than humans as they don’t pause or get tired. They could also give consistent pressure and timing. But this hype has not come into actual practice as a recent Cochrane review has shown [1]. Sometimes some have shown harm as well. The review had assessed data from 11 trials with 12944 adult subjects.

The authors felt that mechanical chest compression devices used by trained staff are a reasonable alternative when high quality CPR is not possible or dangerous to the provider. Potential situations include:

  1. Limited availability of rescuers
  2. Prolonged ongoing CPR
  3. CPR during hypothermic cardiac arrest
  4. CPR in a moving ambulance
  5. CPR in an angiography suite
  6. During preparation for extracorporeal CPR (ECPR)

A simulation study on the quality of CPR between manual chest compression and mechanical chest compression devices performed in an ambulance has been reported [2]. It was a manikin based study of 96 participants as well as two types of mechanical compression devices. One minute continuous chest compression was performed when the ambulance was idle, travelling at 30 km/hour and at 60 km/hour. In manual compression, significant variation was noted among different speeds in terms of average compression rate and depth as well fraction of insufficient compression depth and fraction of normal hands positioning. Automatic compression devices were not affected by ambulance speed, though there was difference between the two devices tested.

References

  1. Wang PL, Brooks SC. Mechanical versus manual chest compressions for cardiac arrest. Cochrane Database Syst Rev. 2018 Aug 20;8:CD007260.
  2. Kamauzaman THT, Ngu JTH, Arithra A, Noh AYM, Siti-Azrin AH, Nor J. Simulation study on quality of CPR between manual chest compression and mechanical chest compression devices performed in ambulance. Med J Malaysia. 2021 Mar;76(2):171-176.