IPPV - failure to deliver ventilation

Failure to ventilate despite apparently appropriate ventilator settings and exclusion of patient factors requires assessment of which ventilator settings are not being delivered.

Poor gas exchange

• Increase FIO2 to 1.0 and start manual ventilation.

• Exclude patient factors.

• Check endotracheal tube is correctly positioned, patent, and both lungs are being inflated. Consider tube replacement.

• Check ventilator circuit is both intact and patent, and ventilator is functioning correctly. Check ventilator settings, including FIO2, PEEP, I:E ratio, set VT, respiratory rate and/or pressure control.

Low VT or low pressure alarm

Expired VT will be lower than inspired VT with bronchopleural fistula. In other situations where expired VT is suddenly significantly lower than inspired VT, or maintenance of circuit pressure is not possible, there is a leak in the ventilator circuit. The patient should be manually ventilated while the leak is identified and corrected. If the leak persists with manual ventilation, repositioning or replacement of the endotracheal tube is required.

High pressure alarm

A sudden increase in airway pressure indicates a change in resistance to gas flow. After patient factors have been excluded:

• Check patency of the endotracheal tube (e.g. with a suction catheter); re-intubate if in doubt.

• Check patency of ventilator circuit and catheter mount. Look for excessive trapped water partially occluding the catheter mount.

• Check for sputum obstructing the HME.

• Consider a chest X-ray to identify endotracheal tube malposition (e.g. cuff above vocal cords, tip at carina, tube in main bronchus).