Zeid’s Critical Care Post – Chest Compressions in CPR

Hands off? Never!!

We have all heard that tweeter go off, “60 year old male, cardiac arrest with downtime of 20 minutes. No shocks advised and coming in a BLS unit.” As your airway and vascular access pathways run through your head, EMS comes in through Resus 4 bagging your patient while performing chest compression. They start giving you their prehospital report and while unfastening the patient from the EMS stretcher and transferring him to the hospital bed, compressions stop. Anywhere from 5-15 seconds later the patient is now on the bed and the designated team member resumes compressions.

The importance of high quality CPR is stressed during our BLS/ACLS courses. The trend continues during any high-level resuscitation lecture that you might have heard. The AHA repeats this point several times in their guidelines;

“Increased emphasis has been placed on high-quality CPR using performance targets (compressions of adequate rate and depth, allowing complete chest recoil between compressions, minimizing interruptions in compressions, and avoiding excessive ventilation).”

Of the many interventions we do, the intervention shown most to correlate with survival and positive neurological outcomes is high quality chest compressions. A lot of resuscitation research is based off animal models, for obvious reasons. Berg et all described a significant drop in coronary perfusion pressure when chest compressions are interrupted. This is depicted in the image below:

Click here for graph

An important take away point is not only the significant and sudden drop in coronary perfusion pressure when chest compressions are interrupted but also the additional time required after resumption to reach previously achieved levels of perfusion. This time period has been estimated to be anywhere from 40-45 seconds during animal studies and were shown to be associated with worsening outcomes. The red arrow in the graph above highlights this period.

Paradis et all highlighted this point when they showed that ROSC is associated with higher initial and maximal coronary perfusion pressure during CPR in humans. Christenson et all also found that patients who receive longer periods of uninterrupted chest compressions are more likely to survive. These studies are in the references for further reading.

Other significant barriers to uninterrupted compressions include pulse checks and airway management. This is difficult to avoid but attempts should be made to minimize pulse check during CPR and this is reflected in the AHA guidelines as well. In the appropriate situation, EtCO2 monitoring can serve as a useful surrogate for determining ROSC. A sudden increase of >10mm Hg has shown to be an indicator of ROSC and thus allowing you to minimize interruptions for pulse checks. Obviously, this requires endotracheal intubation and represents a limitation of this method.

This brings forward the next reason for interruption in chest compressions: endotracheal intubation. In our EMS system, a majority of cardiac arrest patients come in with BVM or a supraglottic airway such as a combi-tube or King airway in place. While there is some debate regarding the timeliness of endotracheal intubation during cardiac arrest, there is no doubt that should be achieved with minimal interruptions in chest compressions. Some studies suggest that passive oxygenation (i.e. nasal cannula or non-rebreather mask) may be superior to BVM ventilation. The literature also suggests that ET intubation may be deferred till ROSC with no significant differences in outcomes. Endotracheal intubation, if attempted, should be performed by an experienced provider since the incidence of esophageal intubation is estimated to be 3-15%. This results in worsening hypoxia and hypercarbia. Additionally, Wang et all found that the median duration of all endotracheal intubation associated interruptions is about 105 seconds and represents about 23% of all interruptions in chest compressions. In summary, there is not a lot of definitive evidence regarding airway management in cardiac arrest patients but use your clinical judgment to ensure first-pass success and minimize interruptions in compressions.

In conclusion, when that cardiac arrest patient is wheeled in to your resuscitation room you should assign someone to take over compressions from EMS immediately. We already have dismal survival rates for out of hospital cardiac arrest in the metro Detroit area and it is your obligation to provide your patient with the best possible chance of survival.


  1. Berg RAR. Circulation (New York, N.Y.): Adverse hemodynamic effects of interrupting chest compressions for rescue breathing during cardiopulmonary resuscitation for ventricular fibrillation cardiac arrest. American Heart Association, etc; 11/2001;104:2465.
  2. Cardiopulmonary resuscitation for cardiac arrest: the importance of uninterrupted chest compressions in cardiac arrest resuscitation, Cunningham, Lee M. et al. The American Journal of Emergency Medicine , Volume 30 , Issue 8 , 1630 – 1638
  3. Christenson J,Andrusiek D, Everson-Stewart S, et al. Chest compression fraction determines survival in patients with out-of-hospital ventricular fibrillation. Circulation 2009;120(13):1241-7.
  4. Paradis NAN. JAMA : the journal of the American Medical Association: Coronary perfusion pressure and the return of spontaneous circulation in human cardiopulmonary resuscitation. American Medical Association; 02/1990;263:1106.
  5. Wang CC. Resuscitation: The association between timing of tracheal intubation and outcomes of adult in-hospital cardiac arrest: A retrospective cohort study. Elsevier; 08/2016;105:59.

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