If the patient receiving NIV is not improving, consider:
- Chest physiotherapy, if the patient has copious secretions.
- Is medical therapy maximal? Nebulizers can be entrained into the NIV circuit but in general, where possible, should be given off NIV as the delivery rate is not controlled on NIV.
- Has a complication such as pneumothorax or aspiration pneumonia developed?
- Consider whether the oxygen delivery is excessive; oxygen can be added at a flow rate of 1–4 L/min, target arterial oxygen saturation of 88–92%.
- Check NIV is working:
- Switched on
- Connected
- Not alarming
- Delivering a pressure at the mask end
- Check for a mask leak, and if present adjust the mask. Loosen straps and reseat the mask. Do not simply tighten the straps, as this can squash the membranes and increase the risk of nasal bridge ulceration. Nasogastric tubes, if needed, should be fine-bore to reduce mask leak.
- Persistent hypercapnia, when none of the above applies, is likely to be due to inadequate ventilation. If continuing with ward based NIV in general the next step would be to increase the IPAP by an increment of 2–5 cm H2O (most machines deliver a maximal IPAP of ∼30 cm H2O).
- In the case of persistent hypoxia consider increasing the FiO2 or increasing the EPAP.
- Arterial blood gases should be rechecked one hour after changing NIV settings.
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