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It’s the kind of Friday where the air still smells like cut grass and warm asphalt from an afternoon thunderstorm that cleared out just in time for sunset.
You and your partner split a bag of kettle corn from the vending machine having one of those philosophical compromises where half is sweet and half is salty, and somehow both are perfect. You’re mid “discussion” about whether caramel belongs on popcorn at all when the CAD chirps and sends you across town to a 68-year-old male with difficulty breathing.
The address pulls you to a narrow rowhouse on the east side of your district, the kind of block where every porch has a rocking chair and somebody’s always out walking a dog at any hour.
You grab you box if life and bag of tricks and make your way up to the house. A woman in her mid-sixties opens the door before you even knock. She’s been watching for the lights.
“He’s in the back bedroom. I found him about twenty minutes ago. He wasn’t like this when I came home from dinner with my sister, I promise you.”
You follow her down a short hallway past a line of family photos of grandkids, what looks like a beach vacation from the early 2000s, a wedding portrait.
On the kitchen counter, there’s a pharmacy prescription bag, a small pill organizer open to Friday, and an empty cup of water. You file that away. Down the hall, the door is open. You can hear him before you see him.
In the bedroom, Leonard is sitting on the edge of the bed, leaning forward with his elbows propped on his knees in the classic tripod position. A nasal cannula loops from his nose back to a concentrator humming in the corner with what looks like enough tubing to outline a zip code.
His chest is moving, barrel-shaped, you note, with a prolonged exhale and the subtle but unmistakable use of accessory muscles. His lips aren’t blue, but they’re not exactly pink either. His eyes are half-lidded, and when you introduce yourself and kneel in front of him, he raises his chin. That’s all he’s got right now to give.
“Leonard, I’m one of the EMS providers. Can I shake your hand?”
You take his hand while your partner starts attaching the monitor. His grip is slow and weak. His skin is warm and dry, not diaphoretic, which is a small reassurance. You keep your voice unhurried.
“How long have you been sitting like this?” He states “A…Few… days.” You repeat, “A few days you’ve been working to breathe, or few days since it got bad like this?” He replies, “Both. Yeah. Both.”
His wife is standing in the doorway. You turn to her briefly. You ask “Has he used his nebulizer today?” She states, “He says it makes his heart race so he stopped using it as much. Maybe once this week.
You ask what his normal oxygen use is. She says, “Just two liters.” You ask if, “He has he seen his pulmonologist recently?” His wife states, “He was supposed to go last month. He cancelled it. He thought he was doing better.”
You look back at Leonard. He’s watching you with that look that sick people get when they’ve been managing something slowly getting worse and they’re surrendering. You give him a nod and reassure him you got him! He replies with a struggling “Okay!”
That one word cost him more than you’d like. Your partner turns the monitor toward you.
So, what do you think? How is he doing?
You ask your partner to pull out the CPAP and prep it along with gesturing with the pinching of a albuterol bullet. Your partner asks if you want a DuoNeb. You ask if Leonard had a temp and your partner replies with, “Nope, 98.8.”
You agree to the DuoNeb and turn back to Leonard. He’s still tripoding, still using accessory muscles, still getting the job done on sheer stubbornness. You talk to him like a person, not a condition.
“Leonard, I want to put a mask on you that’s going to help push the air in. It’s going to feel a little different at first, like the air is coming at you, but it’s going to make breathing a whole lot less work. You’ll still be doing the breathing. The mask just helps.” He nods and follows with …”Yeah. Okay.”
Your partner gets the mask seated and sealed. You coach Leonard through the first few breaths, you can see the muscles in his neck and between his ribs begin to let go, just slightly, as the pressure support takes over some of the work. You turn to his wife and explain what you are doing, loud enough also for Leonard to hear.
Three minutes in, you check the monitor again.
How’s he looking now?
You let him know you are going to give him some steroids and run him up to University to be monitored and work on potentially a new medication regime. He agrees and you get Leonard onto the cot with minimal effort on his part, mask still in place.
His wife grabs his wallet, his medication list, she’s kept one on the fridge, because she’s done this before and like a 2026 hospital stay champ, his phone charger. In the unit, you call to University mentioning his EtCO2 trend, his home O2 regimen, and the missed pulmonology appointment.
As you pull into the bay, you ask Leonard a serious medical question. “Kettle corn, should it be more sweet or salty?” Leonard replies back quickly with a grin under his mask “Sweet!”
Unpacking the Numbers
Let’s take this in order. The SpO2 of 88% on two liters of home oxygen is concerning in isolation, but in a known, advanced COPD patient, it may be closer to their baseline than you’d expect.
The more important question is: where is it relative to their normal? Leonard’s wife confirms he usually runs “in the low 90s” at rest on his concentrator. Tonight he’s below that on two liters with significantly increased work. That delta matters.
You note, intentionally, that you’re targeting 94–96% in a known COPD patient, not 100%. The concern about hypoxic drive in advanced COPD is nuanced and often overstated, but the principle remains: you titrate oxygen in COPD rather than flooding it. You watch the number, you watch the patient, and you don’t chase a number that isn’t safe for this particular lung.
The heart rate of 108 in a resting patient is elevated, full stop. We talked about this in earlier shifts. The resting heart rate should not be in triple digits while someone is sitting in their bedroom. Something is driving it, and in Leonard’s case it’s a combination of hypoxia, increased sympathetic tone from the work of breathing, and as we’ll get to the underlying physiology.
Now the big one (and I say the best): EtCO2 of 68 mmHg. Normal range for a spontaneously breathing patient is 35 to 45. At 68, Leonard is significantly retaining CO2. In acute respiratory distress from a previously normal patient, this would mean severe hypoventilation and impending respiratory failure. But in Leonard, a known advanced COPD patient this may represent his chronic baseline plus acute worsening. The distinction matters clinically, but your treatment direction is the same: he needs more support than he’s getting.
Then there’s the waveform. Look at it carefully.
That sloped, prolonged Phase III instead of a sharp, flat alveolar plateau is the waveform signature of obstructive airway disease. In a normal lung, all alveoli empty at roughly the same time, producing a clean, flat plateau before the sharp downstroke.
In COPD, some alveoli are obstructed more than others. Gas exits unevenly, at different rates, from different lung segments, producing that characteristic upward slope across Phase III. The longer and steeper that slope, the more severe the obstructive physiology.
The other element happening here is intrinsic PEEP, positive end-expiratory pressure that builds up because the lungs can’t fully deflate between breaths. Air traps. The next breath starts before the last one finished.
Over time, this over-inflates the lungs, pushes the diaphragm flat, and reduces the mechanical efficiency of breathing to the point where the patient is working ten times as hard for half the result.
Leonard has been compensating for this for years. Tonight his compensation ran out.
The Pathophysiology Snapshot
In advanced or complex COPD, the patient can have two overlapping processes and create the characteristic capnography pattern. Emphysema destroys alveolar walls, reducing elastic recoil and creating large air spaces that trap gas.
Chronic bronchitis narrows and inflames the conducting airways, impeding airflow. Both contribute to expiratory flow limitation, the inability to exhale efficiently and both show up as a prolonged, sloped Phase III on the capnography waveform.
The EtCO2 value rising above 45 mmHg in a spontaneously breathing patient indicates hypoventilation relative to CO2 production: the respiratory system cannot keep pace with clearing what the body generates.
In Leonard’s case, days of increased work and reduced effective tidal volume led to progressive CO2 accumulation. Acute-on-chronic hypercapnia is the result.
CPAP and BiPAP help by reducing work of breathing (offloading fatigued respiratory muscles), providing PEEP that holds airways and alveoli open long enough for oxygen to diffuse. When you watch the EtCO2 trend down after initiating NIPPV, you are watching the intervention work in real time. It would not be uncommon for it to rise slightly as you put it on initially.
Once they start to oxygenate, ease the work of breathing and get out of the acute stressed state it will come down. The other part that will help is the in-line DuoNeb to reduce the bronchospasm and ease the airway resistance.
***Street Trick: A rising EtCO2 with a shark-fin waveform in a known COPD patient means they are tiring out even if their SpO2 looks “acceptable.” If their EtCO2 was 45 last month and it’s 68 tonight, that trend is the emergency. Don’t anchor to the number in isolation. Trend beats threshold, every time.
Chris Kroboth has been a career paramedic/firefighter for over 17 years and in EMS for over 23. He has been in prehospital and in-hospital education for the past 18 years. His last assignment before returning to operations was as the EMS training captain in charge of continuing education programs and certification. He is also affiliate faculty with the Virginia Commonwealth University Paramedic Program. He is the U.S. clinical education manager for iSimulate and also facilitates national conference clinical challenges to include EMS World, ENA and NTI.
Always learn something from each article. Great information as always!