Q: What’s All That Stuff on the Monitor Mean?

I’m happy to explain everything on the bedside monitor screen, but if I tell you, you have to promise me something: Don’t stare at it.

One thing I can’t bear is having a critically ill patient and walking into their room to find the family staring at the monitor like a preschooler when Paw Patrol is on.

“What’s that number? Is that low? Is it bad?”

The questions spill out of their mouths without reserve. They’re stressed. They want to know everything is alright. Or, they want to be prepared for the worst case scenario. They see that monitor as something plugged directly into their loved one’s “live or die button.”

Here’s something I want all of you to know: You need to take your eyes off of the monitors and put them on the person you love. If you’re at the bedside, stay there. You are not at the “monitorside.” We are at the monitorside at the nurses’ station. It’s our job to keep track of the monitor. We are slaves to it, but we are considering an uprising. We mostly hate the monitors, trust me. Of course, they give us vital information (because it shows the vital signs…get it? I’m here all week), so we’ll never have a full-on revolt, but we still hate them nonetheless.

To reiterate, I say “mostly hate” because they are important and we do rely on them. Having said that, they suck. Why? The best way to explain the awful relationship nurses have with monitors is to break down exactly what most of the normal things are on monitors and why they are both good and bad. Of course, they are absolutely mostly good. Like 98% good. But man, that 2%…Grrr…

Anyhow! Moving on!

Let’s start with a scenario—something mild and non-traumatizing. Let’s say we have a healthy young man in his early 20’s who is having chest pain. Eventually, we will find out that he’s perfectly healthy and that his pain is from a muscle strain from recently taking up weightlifting. But, for now, he’s a new patient complaining of chest pain. Obviously, we would have this guy on all of the basic bits of bedside monitoring.

First, Let’s Look at that Blood pressure.

That one.

Yes, it’s everyone’s favorite vital sign: blood pressure. Let’s say this patient is a really nice and cooperative person…hell, he’s so cooperative, let’s call him Buddy. Buddy sees me coming toward him with a blood pressure cuff and he actually raises his arm for me to put the cuff on. WHAT A GUY.

I can’t tell you how many people do not do this. Seriously. I know at least 99.9999% of people coming to the ER (excluding kids) have had their damned blood pressure taken before, yet almost all of them go completely limp and refuse to lift their arm to put a blood pressure cuff in place—even when I am in the middle of attempting to wrap the cuff around an arm. I don’t have to knuckle-punch your boob putting a blood pressure cuff on, ladies—why must you force me to?

Anyway, Buddy lifts up his arm and lets me put the blood pressure cuff on beautifully. I take a step back to admire how amazingly positioned that cuff is. Wow. I’m tearing up a little, even. Buddy then relaxes his arm and I press the little button on the monitor to get the blood pressure cuff to inflate. It fills up to 140 mmHg and then Buddy looks at me nervously, saying, “This kinda hurts, Mike.”

That’s when I realize that it would be great to explain to Buddy how taking a blood pressure works.

Why Blood Pressure cuffs Squeeze So hard

Blood pressure is measured in two numbers, both in terms of millimeters of mercury (mmHg), which is just a unit of measurement for pressure. The first thing a blood pressure cuff has to do to measure this is…and this is important…CUT OFF YOUR CIRCULATION. THERE IS NO WAY AROUND THIS. So when you’re having your blood pressure taken and you think, “Wow, this kinda hurts and it’s making my hand numb,” that’s why. The cuff is literally creating a temporary tourniquet to stop blood flow to your arm.

This is also why, when a manual blood pressure is taken by a nurse, they hold a stethoscope against the inside of the bend of your elbow. They are listening to the blood flow in your brachial artery. If they inflate the cuff and can still hear your pulse, they inflate it more. The automatic cuff does something similar in that it listens. In both cases, the listener is sensitive to noise, so please be still and quiet. People love talking through blood pressure readings. Also, if the cuff is “too tight,” people love screaming through blood pressure readings, which only serves to increase the chances of a repeat blood pressure being required, which creates more screaming…and so on and so forth.

Anyway, Buddy is now sitting nice and quiet with his arm relaxed, and the cuff has tightened enough to cut off his circulation. He sits still, despite the discomfort, as I have now properly explained that blood pressures aren’t designed to be comfortable, and he’s okay with that. The machine is now slowly releasing pressure until the monitor first hears Buddy’s circulation return to the artery. As soon as the first noise of circulation happens, the pressure of the cuff is noted in the monitor. In Buddy’s case, 140 mmHg cut off his circulation, and the first sound was heard when the cuff deflated to 121 mmHg, so the top number of his blood pressure will be 121. Great start, Buddy!

Now circulation has returned to Buddy’s arm, but conditions are not ideal for his brachial artery. There’s still a bit of pressure to fight against with the cuff still inflated. In order to hear the pressure of the artery at rest (basically—perhaps “non-stressed” is appropriate here) between beats, the cuff has to release to the point of the blood in the artery no longer being audible. At the moment the sound cuts out again, the bottom number is recorded. In Buddy’s case, the sound drifted away at 82 mmHg. That means that Buddy’s complete blood pressure is 121/82, which is just fine. Great stuff, Buddy! Time to move on and away from blood pressure…

“But what’s that number in parentheses? The 89.” interrupts someone I assume to be Buddy’s girlfriend of two weeks who never bothered to introduce herself to me, even after I introduced myself. “Is that his pulse?”

She’s asking about that one.

Ah, yes. The mean arterial pressure. The number that no family member seems to like, even though they have no idea of what it means. This is a simple calculation performed by taking the top number (systolic blood pressure, officially) adding it to twice the bottom number (diastolic blood pressure, officially) and then dividing the result by three. This gives you an estimate of the mean arterial pressure, which is important as it shows the average pressure in a patient’s arteries, which tells us how well blood is being pumped to those vital things called organs. Blood pressure cuffs give us a rough estimate of the mean arterial pressure. The only way to get a true accurate recording is to stick a pressure-sensitive line directly into a patient’s artery, but Buddy isn’t even close to sick enough for such a thing, so we have to rely on his cuff to give us an accurate reading, which is absolutely fine. (For a true calculation of mean arterial pressure, click here.)

I tell Buddy that these readings are great, but I’ve set the cuff to go off every fifteen minutes since he is here for chest pain. I reiterate that when the cuff starts inflating, he needs to hold still until the reading is finished.

“But what about that other number? That one with the squiggly line that says 100. Is that his heart rate? Because I heard 100 is a high heart rate. Aren’t you worried?” chimes in Buddy’s girlfriend. She’s the classic “distrustful of hospitals” visitor. She’s the type who thinks we show up to work just to put people at risk, and she’s starting to bug me. Yes, I realize that I made her up. She might be annoying in her approach and manners, but her questions work for this scenario. But honestly, I don’t know what Buddy sees in her.

I get the “aren’t you worried?” question a ton in the ER. If I worried as often as family members and patients thought I should be worried, my head would explode. I wouldn’t be able to focus. I do worry from time to time, but if I worried as much as everyone else wants me to worry, I wouldn’t be able to function. And do you really want your nurse freaking out? No, you want your nurse in control. I’m in control here, Buddy’s girlfriend!


Pulse Oximetry

That one. And for the purposes of keeping things simple, Buddy’s reading is NOT 84. I’m saying it’s 100.

The number she’s asking about is the measurement of pulse oximetry. It’s read as a percentage, so Buddy’s 100 is the best it will ever get. This reading is being taken from the probe I put on Buddy’s finger. The little red light shines through Buddy’s skin and is able to sense the amount of light absorption in the red blood cells and can differentiate between the hemoglobin (an oxygen-carrying protein on red blood cells) carrying oxygen and the hemoglobin no longer carrying oxygen. From this, it produces a percentage of red blood cells carrying oxygen (Buddy’s is 100! Hooray!—ignore the example picture, as that’s a poor reading), and also, since it is looking at blood passing through arteries at a certain rate, it can determine a pulse rate.

That one.

I look at Buddy’s girlfriend after saying this, and she scoffs. “So is the 100 his heart rate or not?” she asks. I take a deep breath, force a smile, and educate his girlfriend who still hasn’t given me her name.

“It’s a percentage. But it can show his heart rate. 100% is great. We are only concerned when it dips below 93%. But if you look up here, this is Buddy’s actual heart rate.”

Cardiac Monitoring

That one.

What I’m pointing to is the squiggly lines that keep dipping up and down in spikes and bumps. This is Buddy’s cardiac monitoring, and it’s showing that his heart is beating at a rate of 76, which is great. The “normal” range is 60-100, but various factors can change what is normal for different people. I’m not going into that here. Buddy is a healthy guy. 76 is great.

The squiggly lines next to the 76 are actually tremendously complicated. For these purposes right now, I’m going to give you a basic idea of what’s going on, because heart rhythms are worth an entire textbook to explain. Just know that we who are monitoring these squiggly lines know exactly what’s going on and it took a lot of blood, sweat, and tears to understand those stupid little lines.

VERY basically, your heart is an electric creature. Every beat is an electrical event. Electricity dictates how well your heart pulls blood in and pushes it out. Your pulse is an electric event. And we measure that electricity. We can measure it so precisely, we can see which part of your heart is stressed (if any) by looking at a squiggly line. Pretty cool, right? Buddy’s heart is in what we call a normal sinus rhythm. This means his heart is beating as it should. This is great. I will cover heart rhythms as best as I can in future posts, so I’m just going to leave things here. Buddy is fine, and the squiggly line is telling us good things. We have good vibes in the room, I’m happy to have explained the monitor to you all, so I’m just going to step out for a minute to check on—

“Hey! But what’s that number in the middle? The one with the other squiggly line that looks weird and says 16…wait…4…wait…35…wait—”


The Stupid Damned Respirations

That one. But really, just ignore it. I’ve probably silenced the alarms on it anyhow.

I take a breath, grind my teeth, and lean against the wall to keep me from falling to the floor kicking and screaming.

Every monitor is equipped with a respiration count, and let me say this loud and clear:


A patient’s respiratory rate itself is important, and it’s just the number of breaths a person takes per minute. This can be simply calculated by watching a person breathe for fifteen seconds and then multiplying that number by four, or watching a person breathe for ten seconds and multiplying that number by six, or watching someone breathe for a full minute and writing that down, or just noticing that a person is breathing normally and writing down your favorite estimate appropriate for their age…the POINT IS…NO ONE TRUSTS THE MONITOR FOR THIS NUMBER.

The respiratory rate on the screen is “monitored” by the cardiac monitoring stickers on Buddy’s chest. There are five in total, and their rate of physical movement on a person’s chest determines the respiratory rate on the monitor. Now, think about how comfortable ER carts are to lie on. Add in the amount of time we expect you to stay in one. Now allow for normal fidgety movement…these are all things that cause the respiratory rate alarm to sound. It tries its best to take the rise and fall of the electrodes on a patient’s chest to mean that this is when their chest went up and down…therefore…a breath! But, no. Respiratory rates on monitors are 99% stupid. There, I said it. I can’t think of a single time a respiratory rate alarm went off and I believed it. Why? Because Buddy—healthy Buddy—just shifted in his bed for a bit to find a comfy spot and his respiratory rate alarmed because it sensed he was breathing 90 times per minute. That’s not possible in a grown man without massive effort. So what did I do? I silenced the alarm.

And I silenced the alarm while staring straight at Buddy’s girlfriend. I can do it with my eyes closed, it’s so reflexive.

Now, don’t get me wrong—there are situations during which close monitoring of the respiratory rate is crucial. I’m thinking of a patient being on a ventilator (a machine connected to a tube in a patient’s throat that most people call “life support”), suffering an opioid overdose, having a PCA pump (AKA: morphine button), or someone with sleep apnea. But, in these cases, THEY GET SOMETHING MORE ACCURATE TO MONITOR RESPIRATIONS. Or, they use end-tidal CO2 (I’m not going to explain that here, no way—maybe later, but that’s more advanced stuff). In other words, when monitoring a patient’s respiration rate is vital, no one uses the basic monitor. And honestly, just watching chest rise and fall is more accurate than this part of the monitor.

So, those are the four basic monitor functions. Buddy and his girlfriend both seem satisfied with my descriptions. I also go so far as to assure them that Buddy’s vital signs are also being transmitted to a monitor at the nurses’ station, so either myself or one of the other nurses can respond if something goes wrong—though I don’t expect this to happen in Buddy’s case. His 12-lead EKG (another future entry) and blood work (another several future entries, I’m sure) all look great, so it’s just up to the doc as to whether or not to send Buddy home or keep him for observation (another future entry).

Since the tension has lifted in the room, I feel free to tell Buddy and his girlfriend about how much the monitors bother me as a nurse.

And they do.

Why I Say That the Monitors Bug Me

(FYI: What I’m really talking about in this section is a perspective on a real problem in healthcare called Alarm Fatigue.)

Yes, they are essential. I’d never do without a monitor on most patients. But, damn are they ever ready to alarm. If a nurse is new or if they don’t have the time to tell the monitor about the patient (AKA: program it and set appropriate parameters aside from the default settings), these things can and will alarm about almost everything. A cough can be interpreted as an unstable heart rhythm. Shifting from lying on one side to the other can be interpreted as respiratory arrest. The list goes on and on.

Monitors are designed by companies who don’t want to take the blame for anything being missed in the clinical setting, and understandably so. But, the result is that the nurse (never the doctor—real talk: the vast majority of doctors have no clue how to work a monitor—it’s not their job to know. This is why a doctor will let a monitor alarm blare on and on while they are standing at the bedside—they truly don’t know how to fix it) has to adjust every monitor to accommodate each and every patient. I try, but sometimes how busy I am doesn’t allow me to adjust the monitor settings, so it alarms at every opportunity. This is especially aggravating when I’m drowning in patients. I mean, imagine that you are way over your head in bullshit, everything is beeping in shrill tones because you are way over your head in bullshit and don’t have a moment to fix it. It can make a person nearly go insane.

If every nurse had the time to reprogram the alarm limits on every monitor to accommodate each patient, the world would be a better place.

The world would be an even better place if everyone knew what the numbers on the monitor meant—thus, this article.

And the world would be a perfect place if everyone knew what everything on a monitor meant and promptly forgot about it all so they could pay attention to the person they are there to see.

Really—Don’t Stare at the Monitor

I get it. The monitor is an active thing. Sometimes your loved one isn’t active. Sometimes they are hooked up to everything and they aren’t able to communicate and the only thing making any noise or movement in the room is that goddamned monitor.

Trust me, despite modern technology and all its miracles, there is nothing more important than paying direct attention to the patient—in your case, your loved one. There is no technology that can replace being present. The monitors are our friends, as they are doing their best to watch over everyone when we can’t be in the room, but they aren’t the most important thing in the room by a long shot.

This is why you, as a loved one at the bedside, should not stare at the monitor. Yes, I realize we are in the age of screen-staring, but seriously, this type of screen-staring is especially depressing. You are there to spend time with someone who is sick and needs your company, not to provide a third-string defense against monitor readings. Even though I’ve described the basic things monitors monitor, you are in no way an expert. Hell, even if you were, you should not be watching the monitor. I’ve seen great off-duty ICU nurses at the bedside with sick loved ones and they are still staring at the monitor, even though they know better.

Of course, if the monitor alarms, it’s tough to ignore. I get that. But monitor alarms are just trying their best to replace direct visual assessment—so keep your eyes on your loved one. If an alarm keeps going off and you’re concerned, hit the call light. The nurse may want to change some settings to make everyone’s life a little less noisy.

So, forgive me and my attitude toward monitors. I do my best to program them for each patient individually so they don’t alarm so much, but it doesn’t always work out. I do believe that a basic education for the general public as to what monitors are telling us is in order, and that’s what I hope to have accomplished here. If you have any comments or questions, I’d be happy to hear them. Thank you for reading all of this.

Oh! I almost forgot! Buddy was discharged with a muscle strain. He’s just fine.

…and his “girlfriend” ended up being his mother. That’ll teach me about making assumptions. She must be in her forties, at least—she looks fantastic. She ended up thanking me for my care. We ended on a high note. Goes to show, you never know how these patient/family/nurse interactions will end.


So who am I to give advice? Your answer is here.

Have a question? Ask here.

And, of course, feel free to leave a comment. I’m okay with being corrected or engaging in conversation.

Related links:

A simple explanation of what blood pressure is: http://www.bloodpressureuk.org/microsites/u40/Home/facts/Bloodpressure

A detailed guide to mean arterial pressure: http://www.bloodpressureuk.org/microsites/u40/Home/facts/Bloodpressure

A good explanation of pulse oximetry: https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/pulse-oximetry

A pretty good Wikipedia article about cardiac monitoring: https://en.wikipedia.org/wiki/Cardiac_monitoring

A detailed article about ECG interpretation: https://nurse.org/articles/how-to-read-an-ECG-or-EKG-electrocardiogram/

Yes, I know the importance of the respiratory rate, and here’s a study evaluating why it is often neglected as a vital sign in the clinical setting: https://clinmedjournals.org/articles/ianhc/international-archives-of-nursing-and-health-care-ianhc-2-050.pdf

Understanding End-Tidal CO2: https://www.americannursetoday.com/understanding-end-tidal-co2-monitoring/

A great article on Alarm Fatigue: https://www.americannursetoday.com/hear-hear-combating-alarm-fatigue/

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