Pulmonary · Topic 6 of 28

Ventilator Troubleshooting

Pulmonary · mechanical ventilation

Ventilator Troubleshooting

Sudden trouble on the ventilator: bag with 100% oxygen, run DOPES, then use peak versus plateau pressure to split resistance from compliance.

Key numbers

Peak minus plateau: resistance vs compliancePpeak > 25 cmH₂O

High peak, normal plateau: airway resistancePpeak − Pplat > 10

Keep plateau pressure ≤ 30 cmH₂OPplat ≤ 30 cmH₂O

01 · FirstCrashing on the vent: disconnect and bag

With sudden desaturation or hypotension on the ventilator, disconnect the patient and hand-bag with 100% oxygen: this releases stacked breaths and separates a ventilator or circuit failure from a patient problem.

02 · The ruleRun DOPES for acute deterioration

Work through DOPES: Displacement of the tube, Obstruction of the tube, Pneumothorax, Equipment failure, and Stacked breaths (auto-PEEP) — the S is added in asthma and is addressed first by disconnecting.

03 · CalculatePeak minus plateau: resistance vs compliance

A raised peak pressure (eg, > 25 cmH₂O) calls for an end-inspiratory hold: peak minus plateau is the resistive pressure; plateau minus PEEP is the elastic (compliance) pressure.

Causes & risk factors

Why it happens

Most vent hypotension: sedation or high intrathoracic pressureHypotension on the ventilator is most often from sedatives and opioids or high PEEP/auto-PEEP; with no tension pneumothorax, bag slowly (2–3 breaths/min) with 100% oxygen and give 500–1000 mL saline.

Presentation

What you'll see

Auto-PEEP: expiratory flow never reaches zeroAuto-PEEP (intrinsic PEEP, breath stacking) is present when expiratory flow has not returned to zero before the next breath; quantify it with an end-expiratory hold in a passive patient.

Low-pressure or low-volume alarm: leak or disconnectionA low tidal-volume or low minute-volume alarm means gas is escaping: circuit disconnection, a cuff leak, or a tube that has migrated up toward the cords — reconnect, check the cuff, recheck tube position.

Do right now

In this order

First moves

Crashing on the vent: disconnect and bag

→

Run DOPES for acute deterioration

→

Hypotension plus rising peak pressure: tension pneumothorax

Why each step

Crashing on the vent: disconnect and bagWith sudden desaturation or hypotension on the ventilator, disconnect the patient and hand-bag with 100% oxygen: this releases stacked breaths and separates a ventilator or circuit failure from a patient problem.

Run DOPES for acute deteriorationWork through DOPES: Displacement of the tube, Obstruction of the tube, Pneumothorax, Equipment failure, and Stacked breaths (auto-PEEP) — the S is added in asthma and is addressed first by disconnecting.

Hypotension plus rising peak pressure: tension pneumothoraxAcute hypotension and tachycardia with a sudden rise in peak pressure on positive-pressure ventilation is tension pneumothorax until proven otherwise: examine the chest and decompress (needle or tube thoracostomy) without waiting for a film.

Management

Orders

Treat auto-PEEP by lengthening exhalationLengthen expiratory time: lower the respiratory rate, raise inspiratory flow (> 80 L/min in severe obstruction) to shorten inspiration, aim for I:E of 1:4 or longer, and treat bronchospasm and secretions.

Suspected displacement: confirm with end-tidal CO₂Suspect tube displacement with loss of the end-tidal CO₂ waveform, a new leak or unilateral breath sounds; confirm position with capnography and tube depth, and reintubate a dislodged tube.

Suspected obstruction: pass a suction catheterIf a suction catheter will not pass the full length of the tube, it is kinked, bitten or plugged: suction, relieve biting, and exchange the tube if the obstruction persists.

Dyssynchrony: exclude DOPES, then treat discomfortPatient–ventilator dyssynchrony (grimacing, biting the tube, double triggering) raises peak pressure; examine the patient and waveforms, exclude the DOPES causes, then increase analgesia-sedation if needed.

Red flags & don'ts

Avoid harm

Auto-PEEP causes hypotension and missed triggering complicationAuto-PEEP raises intrathoracic pressure, lowering venous return and cardiac output (hypotension), and adds inspiratory work so patients struggle to trigger breaths; it is typical in asthma and COPD.

The rules

Know these

Keep plateau pressure ≤ 30 cmH₂OPlateau pressure, not peak, reflects alveolar distension: keep it ≤ 30 cmH₂O, reducing tidal volume when it is higher; a high peak alone in severe asthma does not mean overdistension.

High peak pressure: resistance or compliance?

Commonly confused

Peak pressure	High
Plateau pressure	Normal
Peak–plateau gap	Wide (> 10 cmH₂O)
Causes	Kinked or bitten tube, secretions, bronchospasm
First moves	Suction, bite block, bronchodilator

More detail

Reference

Show 5 reference facts

In an ICU cohort of intubated patients, atelectasis and retained secretions were the most common cause of acute desaturation; edema, tube occlusion or displacement, dyssynchrony, bronchospasm and pneumothorax were less frequent.

A high minute ventilation (> 20 L/min) alone can create auto-PEEP even without airflow obstruction.

In obstructed patients, applied (extrinsic) PEEP can reduce the inspiratory work of triggering imposed by auto-PEEP.

Prolonged FiO₂ above 0.6 risks oxygen toxicity; titrate to an oxygen-saturation target rather than leaving FiO₂ high.

For a suspected ventilator fault with ineffective ventilation, press the oxygen-boost button, call respiratory therapy, and support the patient with a resuscitation bag and bacterial filter.

Pearl

When the ventilated patient crashes, take the ventilator out of the equation: disconnect and bag with 100% oxygen, then work through DOPES.

Sources · Merck Manual Professional — Overview of Mechanical Ventilation · Weingart S. EMCrit 16 — Coding Asthmatic, DOPES and Finger Thoracostomy · Penn Medicine — Ventilator alarm troubleshooting (critical care curriculum card) · Merck Manual Professional — Treatment of Acute Asthma Exacerbations · Acute desaturation in intubated patients. Critical Care (abstract, PMC3061787) · Koshy TV, Varghese AS. Adding an "R" in the "DOPE" mnemonic for ventilator troubleshooting. Indian J Crit Care Med 2018;22:388 · Clinical approach to ventilator alarm management (alarm causes and responses), BMC Nursing 2025 (PMC12210660) · Starter sheet built from the verified AGACNP fact map (facts reviewed 2026-10-15).