In cold January night Howard Snitzer collapsed in front of a Minnesota grocery store and for more than an hour an a half Snitzer had no pulse. It got to the point in the ER that the doctors said there was nothing more they could do but thankfully for Snitzer the flight nurse who had come in the emergency helicopter believed otherwise.
The reason the nurse believed otherwise was because like a growing number of early responders he was trained in capnography, and it was this knowledge that told the nurse that due to the carbon dioxide levels blood was was still flowing into the vital organs like the heart and brain.
When the nurse told the doctors that he thought there was still a chance to save Snitzer they said the man was dead and that the nurse should just walk away.
The nurse “called the emergency room doctor, who told him that I was dead and that they should walk away,” says Snitzer. “And he hung up and he said to the rest of the people in the room, ‘Is anyone else here uncomfortable with walking away from this?’ And they all said yes. And it was at that point that he called Dr. White.”
That’s Dr. Roger White, an anesthesiologist at Mayo Clinic. He’s the one who finally came up with the solution to get Snitzer’s heart beating normally again.
“We just continued believing that the measurement of carbon dioxide pressure said that if we can stop that fatal rhythm, Howard will be OK,” White explains.
After shocking Snitzer’s heart 12 times and administering intravenous drugs, they finally did manage to stop that fatal heart rhythm. When a pulse and a regular heartbeat had been restored, Snitzer was airlifted to the Mayo Clinic.
White says that before the use of capnography, the only way of assessing blood flow to vital organs was by feeling for a pulse or by looking for dilated pupils. He says those methods are very crude and can fail. Snitzer never had a pulse despite good carbon dioxide readings. Without the information from capnography, he says, it would have been reasonable to stop CPR — and Snitzer likely would have died.
“The lesson that I certainly learn from this is you don’t quit — you keep trying to stop that rhythm as long as you have objective, measurable evidence that the patient’s brain is being protected by adequate blood flow as determined by the capnographic data,” says White.
So what it this capnography?
Well it is a machine that is able to measure how much carbon dioxide is being expelled with each breath, and it has been used for years by anesthesiologists to monitor a patient’s breathing during surgery. However in recent years it has started making its way out of the operating room and into the hands of emergency responders.
Gretchen Cuda-Kroen had a chance to find out exactly how it works and provided this description in her post at NPR
At a fire station in Brook Park, Ohio, medical officers put a tube in my nose and hook me up to the machine to show me how it works.
“OK, that last data stream there is the capnography. Now just breathe normal,” Lt. Mark Lynch says, pointing at a graph on the screen that moves up and down when I breathe.
I watch the monitor as I inhale and exhale. “Every time I breathe out, it goes up,” I remark.
“Yes. That’s the exhalation. Right,” Lynch confirms.
There is also a number on the screen that corresponds to the carbon dioxide I exhale — an estimate of carbon dioxide levels in my blood. As I change my breathing, the number changes, too. By breathing rapidly, I blow out carbon dioxide, and the number on the screen goes down. If I hold my breath, it goes up. Lynch explains that if I were unconscious and receiving CPR, the carbon dioxide levels would tell them how efficiently their chest compressions were pumping blood through my lungs and to my organs. Breathing normally, my number is 35.
“Now, during good CPR, this is probably going to be around 25 — if you keep this up in that 25 range, then there’s circulation still going on. … That’s where you’re going to get a positive outcome,” Lynch says.
I’m betting that Howard Snitzer is very thankful to one nurse who knew how this all worked and didn’t give up on him.