Effects of neurally adjusted ventilatory assist on air distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease

Table 2 Respiratory parameters varying pressure support and NAVA assist levels

Ventilator mode	50%		100%		150%
Ventilator mode	PSV	NAVA	PSV	NAVA	PSV	NAVA
Assist pressure (cmH₂O)	6.73 ± 0.70	6.88 ± 1.08	8.20 ± 0.73^b	7.68 ± 1.39	9.74 ± 1.23^c	7.94 ± 1.25
Ppeak (cmH₂O)	11.35 ± 0.91	12.88 ± 3.30	16.01 ± 0.84	16.52 ± 4.82	20.77 ± 0.94	18.81 ± 4.29
EAdi (μV)	14.69 ± 8.72	11.67 ± 8.64	11.48 ± 7.75	11.43 ± 8.13	14.33 ± 6.87^c	11.86 ± 6.34
Respiratory rate (/min)	22.58 ± 5.28	22.34 ± 4.58	21.00 ± 7.71	23.06 ± 5.40	18.10 ± 6.67	19.59 ± 5.52
MVe (L/min)	7.66 ± 2.58	7.39 ± 2.20	8.58 ± 4.22	8.41 ± 3.32	8.84 ± 3.48^c	7.65 ± 3.00
Inspiratory time (s)	0.93 ± 0.21	1.02 ± 0.14	1.10 ± 0.45	1.01 ± 0.21	1.22 ± 0.55	1.05 ± 0.18
Vt (L)	0.35 ± 0.09	0.34 ± 0.10	0.42 ± 0.14	0.38 ± 0.14	0.53 ± 0.21^c	0.40 ± 0.11
Trigger delay (s)	0.17 ± 0.08^a	0.05 ± 0.02	0.25 ± 0.23^b	0.06 ± 0.06	0.34 ± 0.18^c	0.06 ± 0.05
Cycle delay (s)	0.11 ± 0.10^a	0.02 ± 0.01	0.32 ± 0.49^b	0.06 ± 0.11	0.48 ± 0.72^c	0.05 ± 0.07
Work of breathing (μV∙s)	7.31 ± 5.76	6.20 ± 5.96	6.10 ± 5.83	5.11 ± 2.31	7.33 ± 4.13	6.26 ± 3.91
Work of trigger (μV∙s)	1.20 ± 0.68^a	0.89 ± 0.36	1.52 ± 1.25^b	1.11 ± 0.59	2.17 ± 1.08^c	1.20 ± 0.92
(ROI1 + 2) × Vt (L/min)	0.20 ± 0.16^a	0.17 ± 0.13	0.26 ± 0.15	0.20 ± 0.14	0.26 ± 013^c	0.21 ± 0.14
(ROI3 + 4) × Vt (L/min)	0.21 ± 0.12	0.19 ± 0.09	0.20 ± 0.12	0.20 ± 0.11	0.24 ± 0.12	0.22 ± 0.10

EAdi electrical activity of the diaphragm, MVe minute ventilatory volume, NAVA neutrally-adjusted ventilator assist, Ppeak peak pressure, PSV pressure support ventilation, ROI regions of interest, Vt tidal volume
^aSignificant different versus NAVA 50%
^bSignificant different versus NAVA 100%
^cSignificant different versus NAVA 150%

ISSN: 1364-8535