Dopexamine reverses the vasopressin-associated impairment in tissue oxygen supply but decreases systemic blood pressure in ovine endotoxemia.

Research paper by Martin M Westphal, Andreas Wilhelm AW Sielenkämper, Hugo H Van Aken, Henning Dirk HD Stubbe, Fritz F Daudel, Ralf R Schepers, Simone S Schulte, Hans-Georg HG Bone

Indexed on: 31 Aug '04Published on: 31 Aug '04Published in: Anesthesia and analgesia


Since arginine vasopressin (AVP) may reduce cardiac output and, in proportion, oxygen delivery, we studied the efficacy of dopexamine (DPX) as an adjunct to AVP infusion. After 1 h of continuous AVP infusion (0.04 U/min) in healthy sheep (n = 7), DPX was additionally administered in incremental doses (1, 5, and 10 microg. kg(-1). min(-1); each dose for 30 min). After a 24-h period of recovery, endotoxin was continuously infused in the same sheep to induce and maintain a hypotensive/hyperdynamic circulation. After 16 h of endotoxemia, AVP and DPX were given as described previously. AVP infusion increased systemic vascular resistance index and decreased cardiac index in both healthy and endotoxemic conditions (P < 0.001 each). This was accompanied by an augmented pulmonary vascular resistance index in endotoxemia (159 +/- 13 dynes. cm(-5). m(-2) versus 202 +/- 16 dynes. cm(-5). m(-2)) and a decrease in oxygen delivery index (health: 842 +/- 66 mL. min(-2). m(-2) versus 475 +/- 38 mL. min(-2). m(-2); endotoxemia: 1073 +/- 49 mL. min(-2). m(-2) versus 613 +/- 44 mL. min(-2). m(-2)) and mixed venous oxygen content (health: 63% +/- 2% versus 47% +/- 2%; endotoxemia: 68% +/- 2% versus 51% +/- 3%; P < 0.001 each). Small doses of DPX (1 and 5 microg. kg(-1). min(-1)) improved not only the AVP-associated depressions in cardiac index, oxygen delivery index, and mixed venous oxygen content, but also the pulmonary vasopressive effect in both groups. While large-dose DPX (10 microg. kg(-1). min(-1)) also reduced mean pulmonary arterial pressure in endotoxemia (27 +/- 1 mm Hg versus 23 +/- 1 mm Hg; P < 0.05 versus baseline), mean arterial blood pressure decreased (105 +/- 4 mm Hg versus 80 +/- 3 mm Hg) and heart rate increased (84 +/- 4 bpm versus 136 +/- 9 bpm; P < 0.001 versus AVP alone), thereby limiting its therapeutic use.