The latest: Push at least 100 times a minute, but not more than 120, and push at least 2 inches, but no more than 2.4.
(Photo credit: AHA)

CPR Timeline
(American Heart Association)

Fast but not too fast, and deep but not too deep.

That’s the gently tweaked CPR compression guidance offered in the American Heart Association’s new 2015 guidelines for CPR and emergency cardiovascular care, just out in the Oct. 15 edition of Circulation. They’re minor changes, adding upper limits to existing parameters for rate and depth.

The new compression rate is 100–120 a minute; previously it was “at least 100.”

The new compression depth is 2–2.4 inches for adults and adolescents; it had been “at least 2 inches.”

Key data supporting the upper rate limit came from a 2015 study that found, with adjustments for compression fraction and depth, rates from 100–120 were associated with greatest survival to hospital discharge.1 At more than 120, rescuers appeared to tire and not push as hard, decreasing circulation. The compression rate for pediatrics now mirrors that of adults, though standard CPR is still recommended over compression-only CPR in children.

The depth limit was driven by a smaller study that suggested injuries could happen with compressions deeper than 2.4 inches.2 But don’t stop pushing hard, the chair of the AHA’s Emergency Cardiovascular Care Committee says; “Ribs bend with chest compressions,” Clifton Callaway, MD, noted in a summary of the new guidelines, “and the ‘injury’ is usually very mild. It definitely is not life-threatening.”

The new guidelines continue to promote hands-only CPR but also re-emphasize the value of breaths by those who can and will deliver them. Some additional key issues and major changes for BLS providers:

• Trained rescuers are encouraged to perform some resuscitation steps simultaneously (e.g., checking for breathing and pulse at the same time) to get compressions started faster.
• Integrated teams of trained rescuers can use a choreographed approach rather than sequential.
• Increased emphasis has been placed on high-quality CPR using performance targets.
• Criteria for minimizing interruptions are clarified; the goal is a compression fraction as high as possible, with a target of at least 60%.
• For patients with ongoing CPR and an advanced airway in place, a simplified ventilation rate of a breath every 6 seconds is recommended.
• In the area of ancillary devices, the AHA does not recommend the routine use of impedance threshold devices, though it notes combining an ITD with active compression-decompression CPR “may be a reasonable alternative” with the equipment and personnel. In 2010 it said the ITD “may be considered” by trained personnel.

Similarly, the AHA notes evidence doesn’t show a benefit to the use of mechanical CPR devices, but they also “may be a reasonable alternative” where manual compressions are challenging or dangerous.

Some key issues and major changes for ALS providers:

• Vasopressin has been removed from the Adult Cardiac Arrest Algorithm. Combining it with epinephrine offers no benefit over epi alone.
• When EtCO2 is low in intubated patients after 20 minutes of CPR, they have a very low likelihood of resuscitation. Consider that (though not solely) in weighing termination.
• Evidence is inadequate to support the routine use of lidocaine after cardiac arrest, but its initiation/continuation can be considered after ROSC from VF/PVT arrests.

For more on the new guidelines.
emsworld.com

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