Heart–lung interactions during neurally adjusted ventilatory assist

Table 3 Mean central venous and mean pulmonary artery pressures for the entire experimental period

	PSVlow	PSVal	PSVhigh	NAVAlow	NAVAal	NAVAhigh	P value
							Level	Mode	Interaction
Expiratory values
Central venous pressure (mmHg)	10 ± 3	10 ± 3	10 ± 3	11 ± 3	10 ± 3	11 ± 3	0.064	0.091	0.919
Mean pulmonary artery pressure (mmHg)	30 ± 8	27 ± 6	27 ± 6	30 ± 5	29 ± 5	28 ± 5	0.002	0.065	0.208
Transmural central venous pressure (mmHg)	3 ± 4	1 ± 5	2 ± 4	5 ± 4	2 ± 3	3 ± 3	0.06	0.267	0.566
Transmural mean pulmonary artery pressure (mmHg)	22 ± 9	18 ± 8	19 ± 7	24 ± 6	21 ± 5	21 ± 6	<0.001	0.091	0.683
Cyclic pressure changes
Central venous pressure (mmHg)	−0.5 ± 0.4	0.4 ± 0.4	1.0 ± 0.4	−1 ± 0.5	−0.8 ± 0.6	−0.5 ± 0.7	<0.001	<0.001	<0.001
Mean pulmonary artery pressure (mmHg)	−2.2 ± 1.1	0.5 ± 1.4	2.5 ± 1.3	−3.2 ± 0.9	−2.7 ± 1.2	−1.9 ± 1	<0.001	<0.001	<0.001
Transmural central venous pressure (mmHg)	1.3 ± 1.6	0 ± 0.9	−0.9 ± 1.1	1.4 ± 2.4	1.6 ± 1.6	0.1 ± 1.8	0.009	0.08	0.03
Transmural mean pulmonary artery pressure (mmHg)	−0.3 ± 1.8	0.1 ± 0.8	0.5 ± 0.8	−0.8 ± 2.1	−0.4 ± 1.3	−1.2 ± 1.9	0.479	0.078	0.026

Data presented as mean ± standard deviation. Central venous and pulmonary artery pressures (zeroed to atmosphere) and their respective transmural values for the different experimental periods. The transmural values were calculated by subtraction of the esophageal pressure. Cyclic pressure changes are the differences between mean inspiratory and mean expiratory pressures. Data reflect mean values from the analysis of the entire experimental periods. P values from repeated-measures analysis of variance (within-subject factors: ventilation mode, support level). NAVA, neurally adjusted ventilator assist; NAVAal, adequate NAVA level identified by a titration procedure; NAVAhigh, 200% of the adequate NAVA level; NAVAlow, 50% of the adequate NAVA level; PSV, pressure support ventilation; PSVal, adequate level of pressure support ventilation identified on clinical grounds; PSVhigh, 150% of adequate PSV level; PSVlow, 50% of adequate PSV level.

ISSN: 1364-8535