Vent Alarms

So the purpose of this lesson is to review the basics of what mechanical ventilation does for our patients as well as what alarms you will need to know on the NCLEX and as a new grad nurse.


So when we talk about mechanical ventilation we're referring to somebody who is on a ventilator with either an ET tube or tracheostomy tube. The ventilator will push air into the patient's lungs through that advanced airway. So this is creating a positive pressure within the circuit and forces oxygen into the lungs. Remember that when we breathe normally it's a negative pressure pulling air into the lungs, so this is a bit unnatural. You can see here how the air flows into the patient and then when the patient exhales it comes out through a separate tube so that the carbon dioxide and other gases can be released safely. Now these ventilators have several triggers and settings in place to determine whether or not the patient is actually receiving the oxygen it's trying to give them. So what we're going to look at here are two of the most common alarms that you need to know, because they typically indicate that something is preventing your patient from getting the breaths they need.


The first alarm is the high-pressure alarm. Essentially the ventilator is trying to push the air into the lungs and its meeting a lot of resistance and it can't get the air in like it supposed to. Common causes of this would be kinked tubing - so if the ET tube is bent or has gotten clamped by something, that will cause significant resistance and increased pressure. We also see this alarm with excess secretions because the secretions are blocking the tube or the airways and, again, causing resistance to that air flow. Now sometimes when patients are agitated they may tend to bite down on the ET tube which causes that constriction and prevents flow, which causes increased pressure. In these cases sometimes will use a Bite Block to prevent them from biting on their tube. It’s basically a piece of plastic that goes around the tube so that they bite on the plastic and not on the tube. And then whenever a patient coughs they’re physically forcing air back out of the tube against the pressure of the ventilator and that can cause this high pressure alarm to go off.


The second alarm you need to know is the low pressure alarm. What this means is that the ventilator is trying to put air into the lungs but it is sensing that there's no resistance to flow at all. The most common cause of this is disconnection of the tubes or the circuit. The circuit could come disconnected from the ventilator itself or it could get disconnected from the ET tube. The second possibility with a low pressure alarm is that your patient has somehow reached up, grabbed the ET tube, and pulled it out. We call that extubation or self extubation. Both of these situations mean that the patient is no longer connected to the machine that is literally breathing for them.


Once you know which alarm is going off you can troubleshoot to see where the problem lies. If it's low pressure the very first thing you want to check is that your patient still has the ET tube in place then you want to make sure the circuit is all still connected.


Now the biggest problem with ventilator alarms comes in the fact that when you hear the alarm going off from across the unit, you have no idea what alarm it actually is. They all sound the same. A lot of times these alarms go off simply because the patient coughed or because the parameters are not set appropriately. So you'll see people completely ignore ventilator alarms. This is one of the most dangerous forms of alarm fatigue in the hospital.


I once worked on a unit where the teamwork and collaboration between nurses was not very good. People tended to only look out for themselves and their own patients. One day I was taking care of a patient in an Airborne isolation room and as I went to the ante room to remove my PPE, I heard a ventilator alarm going off. I ran out of the ante-room and into my other patients room to find that he had self extubated. I had no idea how long that alarm had been going off. There were three nurses sitting at the nurses station and not one of them looked up until I yelled for help. Luckily the patient was fine, although he did end up getting re-intubated, but it was a sharp reminder to me of how dangerous alarm fatigue can really be.


So let's recap really quick. Remember that ventilation forces air into the patient's lungs by positive pressure. A high pressure alarm means your tube might be kinked, your patient might have excessive secretions, or they might be biting the tube or coughing. A low pressure alarm means your circuit might be disconnected or your patient might have self extubated. It is absolutely imperative that as soon as you hear a ventilator alarm you go into the room and check on your patient. Find out what the alarm is and troubleshoot it based on what you know the possible causes are.


We want you guys to be diligent nurses who are confident and have peace of mind when taking care of patients on a ventilator, because you know exactly what the problem is. Go out and be that nurse who always pays attention to alarms. And, as always, happy nursing!