Nursing care
Ventilator Alarms: the method, the errors, and the exam
Written and reviewed by Dana Whitfield, RN, MSN · 5 min read · Updated September 2026
Short answer
A ventilator alarm tells you where to look, not what to do first. High-pressure alarms mean something is blocking flow: a kink, secretions, biting on the tube, or the patient coughing. Low-pressure alarms mean air is escaping: a disconnection, cuff leak, or displaced tube. If you cannot resolve it in seconds, disconnect and bag the patient while you troubleshoot.
What the skill is for
A ventilator alarm is a symptom, not a diagnosis. It tells you that pressure, volume or rate has crossed a threshold, and your job is to work out why within seconds, because the patient in front of you cannot breathe unassisted. This is not a skill you reason through slowly at the bedside; it is a skill you recognise instantly, because the two alarm categories point in opposite directions.
High-pressure alarms mean resistance has gone up somewhere between the ventilator and the alveoli: a kinked tube, a mucus plug, biting on the ETT, bronchospasm, or the patient coughing against the vent. Low-pressure alarms mean the circuit has lost its seal: a disconnected tube, a leaking or deflated cuff, or a dislodged ETT. Confusing the two wastes the seconds you do not have. This is why the skill sits at the centre of ICU and med-surg competency checklists, and why it appears constantly on the exam.
The method, step by step
Start by looking at the patient, not the machine. Colour, chest rise, oxygen saturation and level of consciousness tell you whether this is an emergency or a nuisance alarm. If the patient is deteriorating and you cannot identify the cause immediately, disconnect from the ventilator and bag with 100% oxygen using a manual resuscitation bag. Troubleshoot the machine afterwards, with the patient stable.
If the patient looks adequate, read the alarm type. For high pressure: check for kinks along the tubing, suction for secretions, assess for biting and insert a bite block, auscultate for wheeze, and check whether the patient is fighting the vent, which may need sedation review. For low pressure: check every connection point along the circuit, verify cuff pressure and reinflate if needed, and confirm the ETT has not slipped by checking the depth marking at the lips against the documented baseline. Reset the alarm only once the cause is corrected, never to silence it.
Where it goes wrong
The most common error is treating the alarm as the problem, silencing it, and moving on. An alarm that keeps recurring after a reset means the underlying cause was never fixed, and the next occurrence may be worse. A second error is troubleshooting the machine while the patient is visibly hypoxic; in that scenario, bag first, always.
A third error is misreading the direction. New nurses sometimes assume any alarm means the patient needs more suction, when a low-pressure alarm from a cuff leak needs cuff assessment, not airway clearance. Suctioning a patient who has a disconnected circuit delays the actual fix. Always match the intervention to the alarm category before acting.
Practising it deliberately
Drill the two categories as a pair until the association is automatic: high pressure, obstruction; low pressure, leak. Say it out loud during simulation until it no longer requires conscious recall. Then attach a specific intervention to each cause, not to the category in general, so you are not left guessing what 'troubleshoot' means in the moment.
Practise the decision point separately from the troubleshooting: at what point do you stop investigating and bag the patient? Run scenarios where the SpO2 is dropping and the cause is not obvious within five to ten seconds, and rehearse disconnecting and bagging as the default safe action, not a last resort you reach for reluctantly.
Applying it on the exam
NCLEX questions on this topic almost always give you an alarm type and a patient assessment finding, then ask for the priority action. If the stem mentions a high-pressure alarm with new wheeze, the answer is assess and treat the airway, not silence the alarm. If the stem mentions a low-pressure alarm with falling saturation and no obvious circuit problem, disconnect and bag is often the safest first answer among the options.
Watch for distractors that offer 'increase the FiO2' or 'call respiratory therapy' as the first action. Those may be appropriate second steps, but the immediate priority is airway and ventilation via manual bagging, then troubleshooting, then escalation. Answer for the patient in front of you first.
A worked example
A patient on volume-control ventilation triggers a high-pressure alarm. On assessment, the patient is coughing forcefully, SpO2 has dropped from 96% to 89%, and coarse breath sounds are audible bilaterally. The correct sequence is to check the tubing for kinks, then suction the airway, since coughing plus coarse sounds plus falling saturation points to secretions obstructing flow.
Compare this with a patient whose low-pressure alarm sounds and SpO2 drops to 84% with no audible air leak found on quick inspection. Here the safer move is to disconnect and bag immediately with 100% oxygen while a second clinician checks the ETT depth and cuff pressure, because a hidden disconnection or cuff failure cannot be assumed benign while the patient desaturates.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our respiratory practice questions are the closest set to what this page covers.
Common questions
What does a high-pressure ventilator alarm mean?
It means resistance to airflow has increased somewhere in the circuit or airway. Common causes are a kinked tube, secretions, the patient biting the ETT, bronchospasm, or the patient fighting the ventilator. Check the tube, suction, and assess breath sounds in that order.
What does a low-pressure ventilator alarm mean?
It means the circuit has lost its seal and air is escaping instead of reaching the lungs. Causes include disconnection, a leaking or underinflated cuff, or a displaced endotracheal tube. Check every connection and the cuff pressure, and confirm tube position against the baseline depth marking.
When should you bag a patient instead of troubleshooting the alarm?
When the patient is deteriorating and you cannot identify the cause within seconds. Disconnect from the ventilator, bag with 100% oxygen using a manual resuscitation bag, and stabilise the patient before returning to troubleshoot the machine.
How does the NCLEX usually test ventilator alarms?
It pairs an alarm type with an assessment finding and asks for the priority action. Match high pressure to obstruction causes and low pressure to leak causes, and choose airway and ventilation actions over documentation or notification steps when the patient is unstable.