EMT Chapter 25-MCIT-F3-2208 | The Heart Of The Matter :  This course dives into six decades of resuscitation evolution. This is the story of science clawing its way through bad ideas, good intentions, and the occasional accidental break through to give us the CPR of today. 

The lessons covered are

• Lesson 1:  CPR: From Bellows And Barrel Rolls
• Lesson 2:  Life In The ABC Lane: When CPR Got A Rulebook
• Lesson 3:  The CPR Plot Twist: Bye-Bye ABC, Hello cab!
• Lesson 4:  Push Hard, Push Smart: The Metric-Driven Makeover, and,
• Lesson 5:  The Last Lesson… Until the Next Update

Excerpt from EMT Chapter 25-MCIT-F3-2208 | The Heart Of The Matter

Let’s break down what high-quality CPR actually means, because these aren’t arbitrary numbers—there’s solid physiology behind every metric.

First, compression rate: 100 to 120 per minute. Not 80, not 140, but that specific range. Why? Too slow and you’re not generating enough cardiac output. Too fast and you don’t allow enough time for the heart to refill between compressions, which actually decreases the blood flow you’re generating. Think of it like pumping water from a well—if you pump too slowly, you’re not moving much water. If you pump too fast, the well doesn’t have time to refill, and you’re pumping air.

Depth is critical: at least 2 inches, but no more than 2.4 inches. Research using imaging studies showed that you need to compress at least 2 inches to generate adequate pressure gradients and blood flow. But go too deep and you significantly increase the risk of injuries—rib fractures, sternal fractures, internal organ damage. That upper limit of 2.4 inches is there for a reason. In the real world, most providers don’t push deep enough. We’re naturally hesitant to push hard on someone’s chest, but you need to overcome that hesitation.