Sepsis impairs microvascular autoregulation and delays capillary response within hypoxic capillaries

Table 2 Capillary perfusion, O₂ transport, functional capillary density, capillary and RBC function

Variable	Sham (n = 6)	CLP (n = 5)	p value
Capillary perfusion/O₂ transport
RBC SR variation
art SR (RBC/s)	10.8 ± 0.9	9.0 ± 1.6	NS
art SR (RBC/s) CV (%)	43.1 ± 4.3	48.8 ± 2.4	NS
ven SR (RBC/s)	9.7 ± 1.5	7.6 ± 1.1	NS
ven SR (RBC/s) CV (%)	42.8 ± 5.7	58.6 ± 7.6	=0.092
qO₂ variation
art qO₂ (pLO₂/s)	20.7 ± 1.2	14.4 ± 2.1	=0.013
art qO₂ (pLO₂/s) CV (%)	55.4 ± 5.8	76.4 ± 6.5	=0.024
ven qO₂ (pLO₂/s)	16.9 ± 1.9	8.3 ± 1.1	=0.002
ven qO₂ (pLO₂/s) CV (%)	59.7 ± 6.0	79.3 ± 8.1	=0.054
Capillary O₂ ER (%)	19.1 ± 8.0	39.1 ± 7.7	=0.102
Functional capillary density^a
CDcontinuous (caps/mm)	20.8 ± 1.7	15.2 ± 0.8	=0.014
CDintermittent (caps/mm)	3.6 ± 1.1	5.8 ± 1.1	NS
CDstop (caps/mm)	3.6 ± 0.4	8.7 ± 1.1	=0.001
Capillary function^b
art response time (SO₂ < 20 %)	2.1 ± 0.3	7.5 ± 0.9	<0.001
ven response time (SO₂ < 20 %)	2.6 ± 0.7	6.4 ± 1.6	=0.026
RBC function
RBC ATP efflux (H/N)^c	1.48 ± 0.10	0.55 ± 0.04	<0.001

Values are mean ± SE
^aEvaluated on the basis of 30-second flow behavior (intermittent flow = capillary comes to arrest for at least 1 second; stopped-flow (stop) = RBCs are arrested for 30 seconds)
^bCapillary response time = time required for capillary RBC SO₂ to return to values >20 %
^cATP efflux where H/N is RBC ATP efflux ratio under normoxic (N = RBC exposure to 5 minutes 21 % O₂) and hypoxic (H = RBC exposure to 5 minutes 0 % O₂) conditions
art Arteriolar end of capillary network, CD Capillary density, CLP Cecal ligation and perforation, CV Coefficient of variation (= SD/mean; based on 30-second RBC SR and RBC qO₂ profiles), ER Extraction ratio, qO₂ Capillary oxygen supply rate, RBC red blood cell, SO₂ Oxygen saturation, SR Supply rate, ven Venular end of capillary network

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