Nitroglycerin can facilitate weaning of difficult-to-wean chronic obstructive pulmonary disease patients: a prospective interventional non-randomized study

Table 3 Breath components and oxygenation during weaning trials without (Control day) and with (Study day) nitroglycerin

Variable		Mechanical ventilation	Spontaneous breathing trial		P value^a
			Start	End
V_T, Ml	Control day	617 ± 103	289 ± 123^b	298 ± 114^b	0.18
	Study day	608 ± 88	343 ± 114^b	365 ± 73^b
Frequency, beats/minute	Control day	16 ± 3.8	29 ± 7.7^b	29 ± 7.8^b	0.44
	Study day	16 ± 4.1	25 ± 5^b	26 ± 5^b
V_E, L/minute	Control day	9.7 ± 2.9	8.1 ± 3.6	8.3 ± 3.3	0.51
	Study day	9.7 ± 3.2	8.8 ± 3.3	9.4 ± 2.6
f/V_T, beats/minute per liter	Control day	26 ± 8	114 ± 48^b	108 ± 42^b	0.03
	Study day	27 ± 7	82 ± 29^b,c	73 ± 19^b,c
PaO₂, mm Hg	Control day	130 ± 35	65 ± 18^b	66 ± 17^b	0.23
	Study day	132 ± 35	85 ± 18^c,d	89 ± 23^c,d
PaCO₂, mm Hg	Control day	51 ± 10	69 ± 13^b	70 ± 13^b	0.20
	Study day	49 ± 11	61 ± 13^b,c	64 ± 16^b
pHa	Control day	7.41 ± 0.06	7.32 ± 0.07^b	7.30 ± 0.07^b	0.20
	Study day	7.42 ± 0.05	7.34 ± 0.06^d	7.34 ± 0.07^b
SaO₂, percentage	Control day	98.3 ± 1.6	89.2 ± 6.2^b	88.8 ± 4.7^b	0.01
	Study day	98.2 ± 1.5	95.3 ± 2.2^c	94.9 ± 2.2^c
SvO₂, percentage	Control day	75.7 ± 3.5	67.3 ± 7.2^d	69.3 ± 7.5^d	0.04
	Study day	73 ± 4.1	72.3 ± 4.3^c	74.6 ± 4.3^c
Qs/Qt, percentage	Control day	15.0 ± 6.0	37.8 ± 17.8^b	39.5 ± 13.8^b	0.04
	Study day	14.3 ± 5.9	25.7 ± 6.6^c	28.5 ± 8.1^d
O₂ER, percentage	Control day	24.4 ± 3.3	24.7 ± 8.4	22.9 ± 8.5	0.32
	Study day	27 ± 4.1	24.8 ± 4.4	22.1 ± 4.5

Values are presented as mean ± standard deviation. ^aP value of the interaction (day × time) of the repeated-measures two-way analysis of variance comparison between the Control day and Study day across time (that is, during mechanical ventilation, the second minute [for breath components] or 10th minute [for oxygenation variables] [Start], and the last minute [End] of the spontaneous breathing trial). ^bP < 0.001 versus mechanical ventilation. ^cP < 0.05 versus control day. ^dP < 0.05 versus mechanical ventilation. f/V_T, frequency/tidal volume (index of rapid shallow breathing); O₂ER, oxygen extraction ratio; PaCO₂, arterial carbon dioxide partial pressure; PaO₂, arterial oxygen partial pressure; pHa, arterial pH; Qs/Qt, venous admixture; SaO₂, arterial oxygen saturation; SvO₂, mixed venous oxygen saturation; V_E, minute ventilation; V_T, tidal volume.

ISSN: 1364-8535