Vascular and extravascular volume expansion of dobutamine and norepinephrine in normovolemic sheep

Christopher T. Stephens, Nabeel Uwaydah, George Kramer, Donald S. Prough, Michael Salter, Michael P. Kinsky

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


In low-flow states, such as circulatory shock, both fluids and catecholamines are often coadministered. We have previously found that adrenergic agents alter volume expansion after a fluid bolus. The present study tested the volume expansion properties of dobutamine and norepinephrine in sheep treated with (series 1) and without (series 2) a fluid bolus. Series 1 (n = 6 per group): no drug (control), dobutamine (10 μg • kg -1 • min -1), or norepinephrine (1.0 μg • kg -1 • min -1) was begun 30 min before a 24-mL • kg -1, 20-min, 0.9% NaCl bolus. The effect of drug and fluid on plasma volume (ΔPV), urinary output (UOP), and extravascular volume (ΔEVV) was determined. Series 2: Identical protocol but no fluid bolus. Series 1: the fluid bolus resulted in a peak and sustained ΔPV expansion. Norepinephrine (7.5 ± 0.9 mL • kg -1) and dobutamine (9.5 ± 1.1 mL • kg -1) significantly increased ΔPV compared with control (3.8 ± 1.1 mL • kg -1). Cumulative UOP was reduced by dobutamine (3.8 ± 1.4 mL • kg -1) compared with norepinephrine (25.1 ± 3.9 mL • kg -1) and control (16.9 ± 4.0 mL • kg -1). Norepinephrine increased ΔPV, while reducing ΔEVV after bolus. Series 2: ΔPV was unchanged in the control group. Dobutamine and norepinephrine increased ΔPV over time, 5.1 ± 0.5 and 4.0 ± 0.5 mL • kg -1, respectively. At study end, UOP was lowest in dobutamine. Norepinephrine resulted in loss of ΔEVV fluid. data suggest a novel role for adrenergic receptors in regulating vascular and EVV expansion. β-Adrenergic agonists enhance vascular volume expansion, whereas α-adrenergic agonists eliminate extravascular fluid.

Original languageEnglish (US)
Pages (from-to)303-311
Number of pages9
Issue number3
StatePublished - Sep 2011


  • Fluid therapy
  • adrenergic agonists
  • catecholamine infusions
  • dobutamine
  • norepinephrine
  • sheep
  • vascular volume expansion

ASJC Scopus subject areas

  • Emergency Medicine
  • Critical Care and Intensive Care Medicine


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