EFFECT OF CONTINUOUS ARTERIOVENOUS HEMOFILTRATION COMBINED WITH SYSTEMIC VASOPRESSOR THERAPY ON DEPRESSED LEFT-VENTRICULAR CONTRACTILITY AND TISSUE OXYGEN DELIVERY IN CANINE ESCHERICHIA-COLI SEPSIS

Background: In a previous study, we showed that continuous arterioveno us hemofiltration (CAVH) reversed the depression in left ventricular ( LV) contractility in canine Escherichia coli sepsis by the removal. of a circulating substance the molecular weight of which is less than 30 ,000. Despite the normalization of LV contractility, however, we were unable to demonstrate an improvement in systemic arterial blood pressu re (BP), presumably because the mechanisms underlying the depression i n LV contractility and the decrease in BP are different in sepsis, In the current study, we examined the effect of combined treatment with C AVH and the alpha-adrenergic agonist phenylephrine on LV mechanics and tissue oxygen delivery in our canine E. coli model. Methods: Measurem ents were obtained at baseline (condition B). after 4 h of sepsis (con dition S), and after 2 h of CAVH and phenylephrine (condition P) (tota l of 6 h of sepsis). During P, phenylephrine was infused to restore BP to that found at baseline, The slope of the end-systolic pressure-dim ension relation was used as the index of LV contractility; LV anterior -posterior dimensions were measured by sonomicrometry. Results During combined CAVH and phenylephrine treatment, the decrease in the slope o f the end-systolic pressure-dimension relation otherwise observed at S was reversed. The slope (mean +/- SD) was 57.5 +/- 32 mmHg/mm at B ve rsus 22.2 +/- 8 mmHg/mm at S (P < 0.05, B vs, S) versus 62 +/- 37 mmHg at P (P < 0.05 S vs, P) (analysis of variance), Mean BP was restored to that found at B (123 +/- 19 mmHg versus 82 +/- 14 mmHg (P 4 0.05 B vs. S) versus 116 +/- 27 mmHg (P < 0.05 S vs. P), Combination treatmen t with CAVH and phenylephrine also improved stroke volume (39.3 +/- 13 .5 versus 32 +/- 8 versus 44 +/- 12 ml) and tissue oxygen delivery dur ing P compared with results obtained when phenylephrine was given alon e. Conclusions: Our study offers a rationale for the combined use of p henylephrine and CAVH in the reversal of cardiac depression and hypote nsion in sepsis.