Postischaemic regional microvascular variations in the porcine renal cortex

Regional microcirculatory differences in the superficial renal cortex were studied before and during 4 h following 60 min of renal ischaemia in seven pigs under continuous intravenous chlormethiazole-pancuronium anaesthesia. Superficial renal cortical blood flow (Qsrc) was measured by laser Doppler flowmetry (LDF) in two different regions. In two other different regions tissue oxygenation (PtO2) was measured by surface electrodes. Thus, microcirculatory measurements were simultaneously carried out in each animal in four different regions of the left kidney. After 60 min of renal ischaemia, pronounced renal cortical microcirculatory disturbances were found. The regional microcirculatory differences were notable, especially after ischaemia. On average, Qsrc was 49 +/- 11 (s.d.) arbitrary units at baseline and decreased to 24 +/- 4 arb. units 4 h after start of reperfusion (P less than 0.05). Before ischaemia the average difference between Qsrc simultaneously measured in two different parts of the renal cortex was 26 +/- 15% of the mean of both measurements, and it was 30 +/- 22% 4 h after start of reperfusion (n.s.). Mean PtO2 (m-PtO2) was on average 4.5 +/- 1.3 kPa at baseline and 2.4 +/- 1.5 kPa 4 h after start of reperfusion (P less than 0.05). The average difference between m-PtO2 simultaneously measured in two different parts of the renal cortex at baseline was 24 +/- 13% of the mean of both measurements and 57 +/- 49% 4 h after start of reperfusion (n.s.). In each of the two measured regions of the renal cortex m-PtO2 was calculated from 160 small tissue volumes distributed within a surface area of about 1 mm2.(ABSTRACT TRUNCATED AT 250 WORDS)