Effects of dopexamine on blood flow in multiple splanchnic sites measured by laser Doppler velocimetry in rabbits undergoing cardiopulmonary bypass

Abstract

Decreased gut perfusion has been reported during cardiopulmonary bypass (CPB). Studies of treatments to avoid splanchnic ischaemia during CPB have given conflicting results. We studied 12 rabbits during mild hypothermic non-pulsatile CPB. Tissue blood flow in three different splanchnic areas (gastric, jejunum and ileum) was measured by laser Doppler velocimetry (LDV) before CPB (T0), after steady state (T1), after administration of dopexamine 2 micrograms kg-1 min-1 (T2) and 4 micrograms kg-1 min-1 (T3), and after return to baseline (T4). Splanchnic blood flow decreased during CPB. Dopexamine increased significantly jejunum LDV (100% at T1 to mean 271 (SD 210)% at T2) and ileum LDV (100% at T1 to 187 (112)% at T2). Gastric LDV was not altered by infusion of dopexamine during CPB. This could partly explain the conflicting results on the value of gastric tonometry as an index of splanchnic injury.

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“…The administration of dopexamine significantly increased IMBF at all measurement times. Similar increases in IMBF, measured using LDF, during dopexamine administration have been demonstrated in other experimental and clinical settings [17-19]. In a mild hypothermic cardiopulmonary bypass model in rabbits, dopexamine significantly increased jejunum and ileum blood flow, estimated using LDF [17].…”

“…Similar increases in IMBF, measured using LDF, during dopexamine administration have been demonstrated in other experimental and clinical settings [17-19]. In a mild hypothermic cardiopulmonary bypass model in rabbits, dopexamine significantly increased jejunum and ileum blood flow, estimated using LDF [17]. In an experimental setting in pigs, jejunal mucosal blood flow was not influenced by dopexamine infusion during intestinal hypotension, but dopexamine brought about intestinal vasodilatation [10].…”

Bacterial translocation secondary to small intestinal mucosal ischemia during cardiopulmonary bypass. Measurement by diamine oxidase and peptidoglycan

“…Since they are supplied by end-arteries, it is likely that the tip of villi is particularly sensitive to ischemia. In animal models of CPB, blood flow to the jejunal and ileal mucosa during CPB is about one third of pre-CPB blood flow [14,15]. However, these changes have not been documented clinically.…”

Haemodynamic effects of dopexamine on postprandial splanchnic hyperaemia

“…Splanchnic blood flow was found decreased during cardiac shock and cardiopulmonary bypass (CBP) as well [22,23]. Measurements in different splanchnic areas of a rabbit model indicated that the prophylactic use of dopexamine protected jejunum and ileum blood flow but not gastric perfusion [24]. These findings might explain the conflicting results with respect to the effect of the drug on gastric mucosa.…”