Have you ever had a Coke?
How about a flat Coke? What was the difference? It was still good, right? But it was not as good. Why are the bubbles so important to the flavor? The Coke was missing something. Kind of like fries without ketchup, fish and chips without vinegar, lemonade without lemon, or a
Acid is so important to cooking good food: think pickles, lemon zest, vinaigrette, coffee. This article is about medicine, I swear.
But what’s with the Coke example? There’s no acid taken out of Coke to make it flat. Just bubbles. Right?
Let’s do some firefighter level science for just a second here: the bubbles are carbon dioxide. Under pressure, dum dum dum dada dum dum, the carbon dioxide liquifies and mixes with the water. And liquid carbon dioxide is acidic. Hence the name carbonic acid, which is the name of the molecule created by combining water and carbon dioxide. (If this simplified version of chemistry is offensive to you, you are too smart for this article, so please feel free to correct me in the comments or just go to doctor school or whatever.)
So as the carbon dioxide (CO2) breaks free from the water, the carbonic acid is destroyed. The acid disappears from
In a roundabout way, what I’m trying to explain here is that as an EMS worker, when you think CO2, think acid.
Respiratory rate? What’s that?
Exactly. This is the most overlooked vital sign in EMS. Get in the habit of checking respiratory rate (RR) as one of the vital signs you evaluate on every patient. And if it’s elevated, think acid. (There might be other reasons, of course. But until you have ruled out acidosis, they’re not really worth considering.)
If the blood becomes acidic for any reason, the respiratory rate will increase because more respirations means more CO2 out and more oxygen (O2) in. Counterintuitively, increased RR is not the result of decreased oxygen. It’s the result of acidosis. Which means that it is entirely possible for a patient in profound respiratory distress to have a peripheral capillary oxygen saturation (SpO2) over 90%.
Failure is between distress and arrest.
Most respiratory distress (not all) in the elderly in Colorado is caused by chronic obstructive pulmonary disorder (COPD). The distress is the result of poor gas-exchange–carbon dioxide is not efficiently escaping the body’s circulating blood. Oxygenation is also diminished but the key factor is trapped CO2. As carbon dioxide continues to be spilled into the blood by cells as a byproduct of energy production, the body responds to ineffective gas exchange with increased respiratory rate.
I’ve wondered whether patients in respiratory failure are completely incapable of following directions or if they are just so focused on breathing that they consciously shutout all stimuli (including the directions of the attending paramedic). At one point in the process, the one turns into the other. Either way, it is an archetypal death-stare presentation. Short choppy breaths. Suddenly the patient that has been leaning forward trying to move as much air as possible will lean back and start to list to one side.
As a paramedic working in the field (I can’t speak for anyone else), a diminishing mentation is the key finding that distinguishes respiratory distress from respiratory failure. Inside of the failure patient, the feedback loop has been overwhelmed. The RR can only increase so much, it’s ability to compensate is finite.The respiratory distress patient compensates and the respiratory failure patient cannot. Once you observe this sign, cardiac arrest is near.
Oh dear! What do I do?
This isn’t a JEMS article. It’s not an excerpt in a paramedic textbook. And it’s not your protocol. So while it might feel like I’ve reached the point in the article where I tell you what treatment plan is most appropriate in what setting, that just isn’t what this is blog about. I only mean to help explain some things that used to mystify me. I hope there is something useful to be found in my particular method of explaining this subject.
The bottom line is that medicine is not about intervention. Treatment is simple. Your patient has x problem, you provide x treatment. Assessment is hard. The real question is not what is the treatment? It’s what is the pathology? And answering that question takes experience, understanding, and (most of all) compassion.
And if this little explanation helps you help your patients, I’d love to know it. Put it in the comments.