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. 2010 Nov 15;14(6):R204. doi: 10.1186/cc9326

Table 2.

Hemodynamics during weaning trials without (Control day) and with (Study day) nitroglycerin

Variable Mechanical ventilation Spontaneous breathing trial P valuea
Start End
HR, beats/minute Control day 91 ± 14 105 ± 14b 111 ± 15b 0.26
Study day 94 ± 16 105 ± 16b 107 ± 13b
sBP, mm Hg Control day 149 ± 19 179 ± 26c 177 ± 25c 0.002
Study day 144 ± 21 142 ± 23d 135 ± 15d
mBP, mm Hg Control day 94 ± 14 110 ± 21b 109 ± 20c < 0.001
Study day 91 ± 14 89 ± 15d 85 ± 12d
RPP, mm Hg beats/minute Control day 13,708 ± 3,166 19,041 ± 4,129b 19,856 ± 4,877b < 0.001
Study day 13,400 ± 2,637 14,738 ± 2,706d 14,625 ± 2,383d
PRA, mm Hg Control day 11.7 ± 3.2 13 ± 5.6 13.3 ± 5.8 0.001
Study day 10.6 ± 2.9 8.3 ± 3.5d 8.7 ± 3.2d
Mpap, mm Hg Control day 29.9 ± 4.8 40.3 ± 6.2b 41.6 ± 5.8b < 0.001
Study day 28.8 ± 5.9 28.3 ± 4.6d 28.3 ± 3.9d
Ppao, mm Hg Control day 14.8 ± 3.8 23.3 ± 7.6b 23.4 ± 7.4b < 0.001
Study day 14.8 ± 4.9 14.2 ± 3.7d 14.8 ± 3.7d
CO, L/minute Control day 6.6 ± 2 8.2 ± 2 8.7 ± 2.5c 0.89
Study day 6.4 ± 2 8.3 ± 2.3c 8.7 ± 2.7b
SV, mL Control day 73.2 ± 22.7 77.8 ± 16.3 78.8 ± 19.5 0.69
Study day 70.3 ± 27.7 80.8 ± 26.8 81.3 ± 24.4
SVR, dyne/s per cm5 Control day 1,084 ± 387 992 ± 300 931 ± 277 0.10
Study day 1,085 ± 361 827 ± 268c 756 ± 252b
PVR, dyne/s per cm5 Control day 199 ± 69 176 ± 70 171 ± 51 0.28
Study day 192 ± 87 147 ± 57 137 ± 57c
LVSW, g-m Control day 78.2 ± 26.4 91.9 ± 31.2 93.4 ± 37.1 0.62
Study day 73.5 ± 33.8 82.9 ± 35.6 78.3 ± 33.1
RVSW, g-m Control day 18.5 ± 9 28.8 ± 8.2b 30.8 ± 11.2b 0.07
Study day 17.6 ± 10.3 22.8 ± 12.1 22.3 ± 10.1d

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 and the 10th minute [Start] and last minute [End] of the spontaneous breathing trial). bP < 0.01 versus mechanical ventilation. cP < 0.05 versus mechanical ventilation. dP < 0.05 versus control day. CO, cardiac output; HR, heart rate; LVSW, left ventricular stroke work; mBP mean arterial blood pressure; mPAP mean pulmonary arterial pressure; Ppao, pulmonary artery occlusion pressure; PRA, right atrial pressure; PVR, pulmonary vascular resistance; RPP, rate-pressure product; RVSW, right ventricular stroke work; sBP, systolic arterial blood pressure; SV, stroke volume; SVR systemic vascular resistance.