Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study

Table 4 Changes in microvascular variables as mean arterial pressure was increased from 65 mmHg to 85 mmHg with norepinephrine

	Mean arterial blood pressure			ANOVA	Linear trend
	65 mmHg	75 mmHg	85 mmHg	P	P
Vascular density (vessels/mm²)
Large diameter vessels	11 ± 1	10 ± 3	10 ± 3	0.81	0.61
Medium diameter vessels	15 ± 3	16 ± 4	16 ± 4	0.82	0.53
Small diameter vessels	24 ± 8	23 ± 8	22 ± 1	0.09	0.03
Microvascular flow index
Large diameter vessels	2.3 ± 0.6	2.3 ± 0.8	2.2 ± 0.8	0.34	0.16
Medium diameter vessels	2.2 ± 0.7	2.2 ± 0.7	2.1 ± 0.9	0.79	0.52
Small diameter vessels	2.1 ± 0.7	2.2 ± 0.7	2.0 ± 0.8	0.69	0.47
Perfused vessels (%)
Large diameter vessels	82 ± 21	80 ± 28	87 ± 6	0.46	0.40
Medium diameter vessels	77 ± 27	77 ± 29	77 ± 6	0.98	1.00
Small diameter vessels	72 ± 26	71 ± 27	67 ± 32	0.55	0.38
Total vessels	75 ± 25	75 ± 27	76 ± 4	0.92	0.73
Heterogeneity flow index
Large diameter vessels	1.0 ± 0.5	1.3 ± 1.2	1.5 ± 1.4	0.07	0.02
Medium diameter vessels	1.6 ± 1.6	1.5 ± 1.4	1.7 ± 1.2	0.86	0.78
Small diameter vessels	1.8 ± 1.3	1.8 ± 1.2	1.7 ± 1.1	0.97	0.80

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