M21Troubleshooting the ventilated obstetric patient

Clinical overview

At three in the morning the call is rarely "the plateau pressure has drifted up by four". It is "she's desaturating", "the alarm keeps going", "she's fighting the ventilator", or "her pressure has dropped". This module is the structured response to those calls in a pregnant or recently delivered patient, where the differential contains everything in general intensive care plus haemorrhage, embolism, eclampsia, amniotic-fluid embolism, aortocaval compression and peripartum cardiomyopathy.

One habit outranks the rest: when a ventilated patient deteriorates suddenly and you are not certain why, disconnect from the ventilator and hand-ventilate with a bag. It takes seconds, it tells you immediately whether the problem is in the machine or the patient, and it relieves dynamic hyperinflation while you think.

Core knowledge

The sudden-deterioration sweep

Work it in this order, out loud, with the team:

1. Airway — is the tube where it should be? Displacement into a bronchus or out of the trachea is the most common and most immediately fatal cause. Capnography, chest movement, air entry, depth at the teeth.
2. Obstruction — secretions, blood, clot, kinking, biting. Pass a suction catheter: it is diagnostic as well as therapeutic.
3. Pneumothorax — reduced air entry, rising pressures, hypotension. In a ventilated patient it can tension quickly; a hypotensive patient with a plausible story is decompressed on clinical grounds.
4. Equipment — circuit disconnection, water, valve failure, tubing, oxygen supply.
5. Stacked breaths — dynamic hyperinflation with trapped gas (M20). Disconnect and let the chest empty.
6. The obstetric differential — concealed haemorrhage, pulmonary or amniotic-fluid embolism, eclampsia, cardiomyopathy, aortocaval compression, high neuraxial block if regional anaesthesia is in play.

The first five are the standard critical-care sweep; the sixth is what makes this an obstetric module. Both run in parallel — a bleeding patient can also have a blocked tube.

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Figure M21.1 — In sudden deterioration, disconnect and bag with 100% oxygen while running airway, obstruction, pneumothorax, equipment, stacked-breath and obstetric checks in parallel; bag feel helps distinguish ventilator fault or trapped gas from persistent patient, airway or lung difficulty.