Table 4.

Effect of various non-invasive respiratory support modes on laryngeal muscle activity.

	Thyroarytenoid muscle	Cricothyroid muscle	Comment
Normal function	Laryngeal constriction early expiratory phase	Laryngeal relaxation during inspiration	Synchronized support of inspiratory dilation/expiratory constriction
PS – NIPPV	Increased inspiratory activity	Decreased inspiratory activity	Increased inspiratory resistance, decreased VT
NAVA – NIPPV	No increase	Normal activity	Improved VT v PS
High frequency nasal oscillatory ventilation	No increase	Normal activity	Spontaneous RR decreased at lower f

PS-NIPPV: pressure supported nasal intermittent positive pressure ventilation; NAVA: neutrally adjusted ventilator assist;