Episode 12 Part 1: ACLS Guidelines – What’s New & Controversial

In Part 1 of this episode on the latest ACLS Guidelines, Dr. Steven Brooks and Dr. Michael Feldman review and debate what’s new and what’s controversial in the the 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Within the  frameworks of Cardiocerebral Rescusitation and the 3 phase model of rescucitation (electrical, circulatory and metabolic), they discuss the importance of high quality CPR, the de-emphasis on early ventilation and the utility of continuous quantitative waveform capnography. Dr. Brooks and Dr. Feldman answer questions such as: of all the therapeutic manoeuvres we do for the cardiac arrest patient, which ones have been shown to improve survival to hospital discharge? What is the evidence for chest compression machines? What is the utility of bedside ultrasound in the cardiac arrest patient? Why is cardiac arrest survival to discharge in Seattle the best in the world? Should we be performing ‘hands-on defibrillation’? and many more…..


 

Written Summary and blog post by Lucus Chartier, March 2011

Links in the chain of survival

  • Immediate recognition of cardiac arrest and activation of EMS system
  • Early CPR with emphasis on good compressions
  • Rapid defibrillation
  • Effective advanced cardiac life support
  • Integrated post‐cardiac arrest care (including therapeutic hypothermia)
  • EMS systems that effectively implement these can achieve witnessed VF cardiac arrest survival of almost 50%

 

Cardiocerebral resuscitation (CCR)

  • New concept emphasizing high quality, minimally‐interrupted CPR to maximize blood flow to the brain
  • C‐A‐B is the new algorithm, as opposed to the previously taught A‐B‐C, because of the realization that arterial oxygen saturation remains high for the first 5‐10min of a cardiac arrest, that recoil of the chest during chest compressions improves oxygenation, that delaying a definitive airway increases survival, and that high qualitycompressions increases survival
    • Caveat: because children usually die as a result of asphyxial and respiratory complications, ventilations should be emphasized for them, and so the ABCs are still the most appropriate algorithm for the majority of paediatric cardiac arrests
  • BLS changes from 2005 Guidelines:
    • Compressions before giving breaths, and pulse checks 10 seconds or less
    • Faster compressions: at least 100 compressions/min, i.e. 30‐compression cycle in 18 seconds or less
    • Deeper compressions: adults – at least 2 inches & children/infants at least 1/3 the depth of chest

Three phase model of resuscitation

  1. Electrical phase – first few minutes after the cardiac arrest: disorganized cardiac activity with minimal ischemia, requiring prompt defibrillation
  2. Circulatory phase – 6‐10min: ischemic insult and injury developing, requiring uninterrupted compressions before defibrillation is attempted, as the heart needs to be ‘primed’ for defibrillation with compressions
  3. Metabolic phase – 10min and after: therapeutic hypothermia and vasopressors may help in postcardiac arrest syndrome

 

Carbon dioxide: Capnography in ACLS Guidelines

End‐tidal CO2 (continuous quantitative waveform capnography) serves 3 purposes in initial resuscitation:

  1. Helps confirm endotracheal tube placement and monitoring displacement
  2. Helps monitor quality of CPR (if ETCO2 < 10mmHg, patient likely needs faster or harder CPR –although epinephrine may lead to decrease in ETCO2 level)
  3. Detects ROSC (return of spontaneous circulation) with abrupt and sustained increase > 40mmHg

 

Pearls about ACLS Guidelines

  • Point of Care Ultrasound should only be used in restricted situations during cardiac arrest rescucitation, in order to determine whether the heart is still beating in light of a potentially reversible cause of cardiac arrest (eg, pneumothorax, cardiac tamponade, hypovolemic shock), and which would prompt you to continue resuscitative efforts
  • Minimize pre‐shock pause between the last compression and defibrillation to increase success
  • Ventilation at high respiratory rates (25 breaths per minute) is common during resuscitation from cardiac arrest. The guidelines say to deliver ventilations at a regular rate 1 breath every 6 to 8 seconds (8 to 10 breaths/minute) without interruption of chest compressions. Ventilating faster will decrease venous return and decrease cardiac output especially in patients with hypovolemia or obstructive airway disease.
  • The upper limit of the rate of sinus tachycardia is determined by the 220 minus the age of the patient
  • The starting dose for synchronized cardioversion in the setting of atrial fibrillation is now to start at 120‐200J (instead of the previous recommendation of 100‐120J)
  • Remember the Hs and Ts, along with their respective treatment:
    • Hypovolemia (fluid, pressors), hypoxia (oxygen), hydrogen ion (NaHCO3 only in certain situations), hypo/hyperkalemia (potassium, or calcium, insulin and glucose), hypothermia (re‐warming)
    • Tension pneumothorax (needle thoracostomy) cardiac tamponade (pericardiocentesis), toxin (antidote), thrombosis (thrombolytic if pulmonary embolus; thrombolytics or cath lab if myocardial infarction)

Key live-saving steps in 2010 Guidelines: The 5 C’s of ACLS

  1. Compressions (hard, fast & uninterrupted)
  2. Cardiovert (defibrillate early)
  3. Capnography (CO2 monitoring)
  4. Cooling (therapeutic hypothermia)
  5. Cath (PCI)

Key References

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About the Author:

Dr. Anton Helman is an Emergency Physician at North York General in Toronto. He is an Assistant Professor at the University of Toronto, Division of Emergency Medicine and the Education Innovation Lead at the Schwartz-Reisman Emergency Medicine Instititute. He is the founder, editor-in-chief and host of Emergency Medicine Cases.

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