Conventional teaching states that altered mental status (AMS) is a contraindication to use of noninvasive ventilation (NIV) due to three main concerns:
- Patients with certain types of AMS have a risk of developing aspiration with positive-pressure ventilation, or NIV.
- Patients whose AMS results in agitated behavior may have reduced cooperation with a tight-fitting NIV mask.
- Due to the tight seal of the NIV mask, secretions cannot be cleared from their mouth if needed.
But not all altered mental status is the same! The presence of AMS is not as important as the type of AMS. For example, patients with coma are different from patients with agitated delirium or patients with confusion.
Using NIV for patients with coma
Literature supports the use of NIV in patients with a low Glasgow Coma Scale (GCS) score. In fact, NIV can be successful in patients with a GCS score of less than 8, especially if the cause of the low GCS score is due to confusion from hypercapnia such as in acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Similarly, mental status changes such as delirium due to an infection may also be amenable to the use of NIV.
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- Gónzalez Díaz, G, Alcaraz, AC, Talavera, JCP, et al. 2005. Noninvasive positive-pressure ventilation to treat hypercapnic coma secondary to respiratory failure. Chest. 127: 952–960. PMID: 15764781
- Scala, R, Naldi, M, Archinucci, I, et al. 2005. Noninvasive positive pressure ventilation in patients with acute exacerbations of COPD and varying levels of consciousness. Chest. 128: 1657–1666. PMID: 16162772