Autoregulation of Spinal Cord Blood Flow

Abstract

The response of SCBF to changes in pACO2 was tested in Rhesus monkeys under normotensive conditions. A sigmoid shaped response was demonstrated. At a pACO2 of 10 to 50 mm. Hg, SCBF remained constant and in the normal range. As the pACO2 was raised from 50 to 90 mm. Hg, SCBF increased. Further increases in the pACO2 above 90 mm. Hg failed to effect further changes in SCBF. We conclude from these data that SCBF is somewhat less responsive than CBF to changes in pACO2. Next, the effect of changes in MAP on SCBF was studied under normocapnic conditions. SCBF remained constant and in the normal range with an MAP of 50 to 135 mm. Hg. Above 135 mm. Hg, SCBF rose with further increases in MAP. With decreases in MAP below 50 mm. Hg, SCBF fell passively. It is our conclusion that autoregulation exists in the lateral white matter of the spinal cord and follows a pattern similar to that suggested for the cerebrum.

Use of hydrogen for measurement of regional cerebral blood flow: problem of intercompartmental diffusion.

“…They reported flow rates for dorsal horn grey matter electrodes which would be more appropriate for white matter (17 cc/100 grams/minute). 12 Due to indicator diffusion between grey and white matter, this measured flow was most likely a weighted mean for the whole dorsolateral quandrant of the spinal cord. This is similar to our inability to demonstrate appropriate grey matter clearance rates (70 to 90 cc/100 grams/minute) in rabbit cortex.…”

Blood supply and vascular reactivity of the spinal cord under normal and pathological conditions

“…Further increases above 90 mm Hg had no effect on SCBF, which had reached a physical maximum. 45 In another study, Kobrine and coworkers 47 found that SCBF remained constant when MABP was between 50 and 135 mm Hg. Below 50 mm Hg, vascular resistance decreased maximally, and SCBF became a function of MABP.…”

“…When MABP fell below 40 mm Hg, SCBF dropped significantly. 38 Kobrine and associates 45 found that when CO 2 pressure was between 10 to 50 mm Hg in monkeys, SCBF stayed constant. When the pressure of CO 2 surpassed 50 mm Hg, SCBF increased.…”

Анатомія Та Патофізіологія Пошкодження Спинного Мозку, Пов’язані З Проведенням Нейроаксіальної Анестезії

“…Раніше межі авторегуляції СМ визначались як САТ від 50-60 до 120-135 мм рт.ст. [24,28]. Протягом останніх років Drummond та його колеги поставили під сумнів прийняте попередньо судження щодо діапазону 50 мм рт.ст., що стано-вить відповідну та сумісну нижню межу авторегу-ляції головного мозку в людини.…”