This document discusses the importance of effective chest compressions during cardiopulmonary resuscitation (CPR). It notes that recent American Heart Association guidelines have emphasized minimizing interruptions to chest compressions and limiting ventilation rates during CPR. The document explains that chest compressions are critical for increasing survival, especially when collapse to shock time is greater than 15 minutes. It also discusses how excessive or interrupted ventilations can decrease blood flow and notes that observed CPR often involves too many ventilations contrary to guidelines. The key message is that effective, continuous chest compressions with few interruptions and limited ventilations are the most important aspect of CPR.

1. The Science Behind Chest
Compressions
Matthew Sholl, MD MPH, FACEP
Maine Medical Center/MaineHealth

2. Curr Op Crit Care 2004;10:208-212

4. Excellent Chest Compressions
are the Foundation of Survival!

5. Recent Changes in ACLS?
• Most recent AHA changes
(2005/2010)attempted to highlight the
importance of uninterrupted chest
compressions and limited the positive
pressure ventilation rate to 8 – 12 breaths
per minute
Why focus on minimally interrupted chest
compressions and limiting positive
pressure ventilation?

8. What’s The Big Deal?
Do Chest Compressions Really Work?

13. • While in early phases
of OHCA (< 5 min), no
benefit to bystander
CPR existed
• As time to shock
increased, see
increasing survival
benefit of bystander
CPR
• No survivors seen if
collapse to shock
interval > 15 minutes

15. The Most Important Treatment
You Offer…
• … is effective chest compressions
• Effective means:
– Right rate (at least 100)
– Right depth (2.5 inches or 5 cm)
– Relax – allow for recoil
– NO interruptions
– Avoid excessive ventilations
• Despite our best ALS capabilities, our BLS
skills are what appears to be most
important

16. Cardio-cerebral Resuscitation
(CCR)
• Based on the Three Phase Model of resuscitation
• Generated in AZ –the AZ Sarver Heart Center
Goals:
1. Minimize interruptions of chest compression
2. Provide immediate post-shock chest
compressions for prolonged VF
– Why is that important?
3. Delay or eliminate endotracheal intubation
4. Minimize all positive pressure ventilation
5. Decrease the time interval to IV Epinephrine

17. Benbrow, B –6th Annual Symposium on Neurologic Emergencies and Neurocritical Care , June 2009, NYC, NY

18. A New Horizon for OHCA…
• Two new thoughts on OHCA:
1.Primary and Secondary Injury
– Primary injury – cardiac arrest
– Secondary injury – brain injury
• Even if we can obtain ROSC – still see large
numbers of deaths
• These deaths predominantly due to hypoxic brain
injury
– Target of therapeutic hypothermia
2.Three Phase Model for Resuscitation…

20. Three Phase Model of
Resuscitation

21. Minimizing Positive Pressure
Ventilation
• Old Paradigm:
– ABC’s – M2M/BVM/ETT to deliver high flow O2
• New Concepts:
– Positive pressure ventilation increases intrathoracic
pressure
– Increased intrathoracic pressure decreases venous
return
– Resultant decrease in coronary and cerebral blood flow
• SO… AHA has recommended RR of 8 – 12
breaths/minute

22. The Message may Not Have Been
Received….

24. • Observational study of EMS
practitioners performing CPR
• Measured ventilation rate
• Average rate = 37 +/- 3 per
minute
– Range 15-49
– Recall: BLS/ACLS
recommends 8-12
• Second part of the study….

25. Disadvantages to Ventilations
During CPR
• Delays/Interrupts chest compressions
• Complicated
• Stops bystanders from doing CPR
• Gastric inflation – aspiration
• Increases intrathoracic pressure
– Reducing coronary/cerebral perfusion
• Animal models show worse outocme

26. What Have We Learned So
Far?
• OHCA happens to a lot of people!!
– One of the top causes of death
• There remain opportunities to save lives
– Especially through engaging laypersons and
both PAD programs as well as by-stander
CPR
• New ACLS/BLS protocols attempted to improve
well preformed, continuous chest compressions
with minimal interruptions
• Despite these recommendations, still see many
interruptions and too aggressive ventilation

27. Questions?

28. Thank You