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Update on Mechanical CPR – 2014

• Dr Anantharaman (from Singapore) shared his expertise about Mechanical CPR at the ICEM 2014 Conference in Hong Kong and I was an interested listener having recently posted on this subject.

Hong Kong – ICEM 2014

• There is a need for improving CPR quality in all countries as survival rates are poor
  • In Singapore it can take >15 mins for trained rescuers to arrive at the scene of a Cardiac Arrest
  • Survival of CPR falls rapidly from the onset of arrest (see graphs below)
  • Mechanical CPR may improve the quality of CPR (the second link in the so-called chain of survival)

• Emergency Medical Systems (EMS) face challenges for transport – both in terms of safety and in terms of the quality of CPR provided in transport – mechanical CPR may help in this respect

• Minimal Interruptions to CPR is ideal because it takes multiple compressions to build up a pressure head:

• Background of Mechanical CPR
  • Originally perfumed on Dogs (successfully) around 50 years ago
  • Later Piston systems showed no mortality benefit in humans (but some haemodynamic benefit)
• Data to date has been mixed on modern devices such as the LUCAS and AUTOPULSE
• One notable 2006 JAMA paper suggested potential HARM from mechanical CPR:

• More recent studies have suggested no benefit from the current devices but with some methodological issues
• The Speakers atICEM suggest that further studies are required due to these issues
  • Clear rules on application of the Mechanical CPR and lack of standardised algorithms
  • Use of intention to treat analysis – may affect results

• Recent Evidence on the various devices includes the following:
  • AUTOPULSE Device
    • CIRC Trial
      • Survival in patients receiving Mechanical CPR has NOT shown benefit in recent trials such as the CIRC Trial (2011).
      • However, the manual CPR in these studies was of higher quality than one would expect.
      • The fraction of effective chest compressions was about the same between groups.
  • LUCAS Device
    • LINC Trial
      • 4-hour survival rate: Mechanical compression group (23.6%) versus the conventional group (23.7%)
      • 6-month survival rate: Mechanical group (8.5%) versus conventional group (8.1%)
      • 6-month good neurologic status (based on Cerebral Performance category of 1 or 2): Mechanical group (99%) versus conventional group (94%)
    • MECCA Trial (Singapore)
      • Provisional results of this as yet unpublished trial were presented:
        • 1189 eligible patients
        • Low levels of survival overall
        • Higher survival in Mechanical CPR group but not statistically significant
  • Using a “Pit Crew” method (Ong 2012) for implementing Mechanical CPR may reduce the time it takes to fit the device and  maximised the time of chest compressions

Take Homes

• How do we deliver better chest compressions?
  • Recent reviews of the evidence have suggested that is unclear whether Mechanical CPR has benefit
  • The presenters at ICEM believe that Mechanical CPR may have a role – especially in transporting patients
  • Modern devices may cause less injury compared to older Piston Types
  • Good CPR requires Teamwork and Training regardless of whether human CPR or machine CPR is used
  • Public Education on the importance of early CPR will save lives as Cardiac Arrest is a pre-hospital event with survival likelihood determined by early intervention (CPR and Defibrillation)

• AEDs which are now widely used in public buildings.  In the same way technology such as Mechanical CPR devices may become increasingly available in the pre hospital setting.
• Mechanical CPR may have a future role despite the disappointing trial data described above
• Technology is likely to advance and more trials of implementation are required in this area

Further Listening – Lecture by Marcus Ong (2011)