Ventilator Troubleshooting
immediate assessment
Ventilated patient suddenly desaturates, alarms, or looks wrong: troubleshoot the patient before the machine. Off the vent, bag with a self-inflating bag on 100% O2, then DOPE in order: Displacement, Obstruction, Pneumothorax, Equipment failure (1).
- bagging fixes it immediately → Equipment: ventilator or circuit problem; reconnect, check settings and circuit for leaks or disconnection.
- bagging easy, saturation recovers, re-deteriorates on the vent → ventilator-specific issue: work through auto-PEEP and dyssynchrony below.
- bagging feels difficult, high resistance → pass a suction catheter down the tube now.
- catheter will not pass, or meets firm resistance → Displacement or Obstruction: kinked, bitten, cuff herniation, mainstem migration, extubation; reposition or change the tube.
- catheter passes freely, suction does not help → Pneumothorax: unilateral absent breath sounds, tracheal deviation, hemodynamic collapse.
do not delay for imaging if
- unilateral absent breath sounds + hypotension + tracheal deviation → tension pneumothorax: decompress now, do not wait for a chest x-ray.
- the patient is peri-arrest on the vent, disconnect and bag while you work the DOPE sequence, get help now.
define & classify
Two pressures localize the problem (2):
| pattern | points to |
|---|---|
| high peak, normal plateau (gap > 5 cmH2O) | airway resistance problem: bronchospasm, secretions, kinked/bitten tube, circuit obstruction. |
| high peak, high plateau (gap small) | compliance problem: pneumothorax, worsening ARDS/edema, auto-PEEP, abdominal distension, mainstem intubation, patient splinting/fighting the vent. |
| low delivered tidal volume, volume-control mode | circuit leak, cuff leak, disconnection, or a pressure-limited breath cut short by high resistance/compliance. |
peak is read during flow. plateau is read on an inspiratory hold once flow stops, reflecting the alveoli, not the airway.
initial management
high peak pressure, resistance pattern
- suction the ETT, check for kinking or biting, insert a bite block.
- bronchospasm/wheeze → albuterol nebulizer 2.5-5 mg, repeat, add ipratropium 0.5 mg nebulized.
- severe bronchospasm not responding → magnesium sulfate 2 g IV over 20 min.
high plateau pressure, compliance pattern
- tension pneumothorax → needle decompression at the 2nd ICS, midclavicular line or, on the right, the 5th ICS, anterior / mid-axillary line (3); then chest tube
- no universally preferred site: follow local protocol; on the left favor the 2nd ICS midclavicular line, the heart sits closer to the axillary sites
- unilateral breath sounds, tube deeper than expected at the teeth → mainstem intubation: pull back to correct depth, recheck bilateral breath sounds, confirm on chest x-ray.
- abdominal distension/raised intra-abdominal pressure → decompress with an NG tube, consider bladder pressure measurement.
- worsening pulmonary edema/ARDS pattern → reassess fluid balance, go to ARDS.
dyssynchrony, fighting the vent
- optimize analgesia and sedation first: fentanyl and propofol infusion, target RASS -2 to 0.
- adjust trigger sensitivity, inspiratory flow, or rise time before adding more sedation.
- persists despite optimized sedation and settings, patient unsafe on the vent → short course of neuromuscular blockade, rocuronium 0.6-1.2 mg/kg IV or cisatracurium infusion, only with adequate sedation running and a plan to reassess.
calculator RASS · MDCalc ↗︎
hypotension right after intubation
- work through AH SHITE (4): Acidosis/Anaphylaxis, Heart (tamponade, pulmonary hypertension, right heart strain), Stacked breaths (auto-PEEP), Hypovolemia, Induction agent, Tension pneumothorax, Electrolytes.
- most common causes: unmasked hypovolemia and vasodilation from induction agents, propofol especially.
- fluid bolus 250-500 mL crystalloid unless obviously overloaded; hold or reduce the sedative infusion; push-dose pressor ready (phenylephrine 100 mcg IV, or norepinephrine push if available).
reassess
- after any intervention, recheck peak and plateau pressure, not just the alarm status.
- repeat arterial blood gas if oxygenation or ventilation was in question.
- flow-time waveform: expiratory flow must return to zero before the next breath; if not, auto-PEEP persists.
- trend blood pressure and heart rate over the next 10-15 min; one normal reading after a bolus is not enough.
advanced management
auto-PEEP / breath stacking
- recognize it (5): flow never returns to zero before the next breath; rising pressures with no DOPE cause; worsening hypotension in an obstructive patient (asthma/COPD) on the vent.
- measure it: end-expiratory hold, the pressure above set PEEP at end-expiration is auto-PEEP (intrinsic PEEP).
- fix it: lower respiratory rate; tidal volume toward 6 mL/kg PBW; higher inspiratory flow to shorten inspiration and lengthen expiration (I:E around 1:4-1:5 in severe obstruction); treat bronchospasm.
- hemodynamic collapse → disconnect from the circuit for 15-30 sec, allow full passive exhalation (gentle chest wall pressure helps), reconnect on more conservative settings; a bedside emergency maneuver, not routine.
dyssynchrony types
- ineffective triggering patient effort fails to trigger a breath, usually auto-PEEP raising the trigger threshold (6): fix the auto-PEEP, lower trigger sensitivity.
- double triggering two breaths stack in one effort, usually inspiratory time set shorter than the patient’s neural inspiratory time: lengthen inspiratory time or switch mode; consider sedation.
- auto-triggering vent fires without patient effort: circuit leak, water in the tubing, or cardiac oscillation; check the circuit before blaming the patient.
troubleshooting
- sudden desaturation / high-pressure alarm disconnect and bag first (see immediate assessment above), work the DOPE sequence.
- low tidal volume alarm, volume-control mode check cuff pressure and circuit for a leak → reinflate cuff, tighten connections; no leak → reassess resistance / compliance (define & classify above).
- hypotension after intubation or a vent change auto-PEEP suspected → disconnect maneuver first, faster than a bolus if breath stacking is the cause (advanced management above); not auto-PEEP → work AH SHITE (initial management above).
escalation / ICU
call ICU / anesthesia urgently for
- tension pneumothorax, decompress first, call in parallel.
- a difficult or failed airway, a tube that will not pass or reposition.
- hypotension refractory to fluid bolus and sedation adjustment, needing vasopressor support.
- persistent high plateau pressure or auto-PEEP despite ward/HDU-level adjustments.
- any DOPE-negative sudden decompensation on the vent that you cannot explain at the bedside.
pearls & pitfalls
- disconnect and bag first, every time. Never troubleshoot the machine while the patient is still on it.
- post-intubation hypotension is common and usually not catastrophic, but work through AH SHITE, do not assume it is “just the propofol.”
- more sedation before checking waveforms and pressures is a common trap: know why the patient is fighting the vent before treating it.
sources
| source | type |
|---|---|
| 1. DOPE mnemonic, ventilator troubleshooting | review |
| 2. High airway and alveolar pressures, LITFL | review |
| 3. Ahmad et al., needle decompression site meta-analysis, World J Emerg Surg 2025 | meta-analysis |
| 4. AH SHITE, post-intubation hypotension, REBEL EM | review |
| 5. Intrinsic PEEP, LITFL | review |
| 6. Pham et al., Asynchrony Consequences and Management, Crit Care Clin 2018 | review |
dosing above follows international guidance. Verify against the current Kuwait / MOH or hospital protocol where locally sensitive.
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Last updated · September 2026