ICU Cases · Mechanical ventilation
The sudden high airway-pressure alarm
A focused CICM short case on the highest-yield bedside discriminating skill in mechanical ventilation — measuring the plateau pressure to separate a resistance problem (airway or circuit) from a compliance problem (lung or chest wall) — and the machine-to-alveolus approach to the cause.
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You are called to a ventilated patient on volume-controlled ventilation whose high airway-pressure alarm is sounding. The peak inspiratory pressure has risen from 24 to 46 cmH2O, the set tidal volume is unchanged, and the patient is now coughing against the ventilator with falling oxygen saturation. You have minutes.[1]
State the principle first: the peak pressure reflects resistance plus compliance, but the plateau pressure reflects compliance alone, so the immediate next step is a 0.5-second inspiratory hold to measure the plateau. That single number forks the differential.[1]
References3ShowHide
- [1]Bersten AD, Soni N (eds). Oh's Intensive Care Manual. 8th edition, Elsevier, 2018.
- [2]Marino PL. The ICU Book. 4th edition, Lippincott Williams & Wilkins, 2014.
- [3]Dreyfuss D, et al. High Inflation Pressure Pulmonary Edema. Respective Effects of High Airway Pressure, High Tidal Volume, and Positive End-Expiratory Pressure. American Review of Respiratory Disease, 1988.PMID 3057957