Mechanism of Pressor Response to l-Norepinephrine During Hemorrhagic Shock

Abstract

Dogs were bled 50 ml./min. until mean systemic pressure approximated 35 mm. Hg. Blood pressure was maintained at this level for 30 min. l-Norepinephrine was then infused in amounts sufficient to increase systemic blood pressure to twice the shock level or more. Measurements of systemic blood pressure, right atrial and pulmonary arterial pressures and of direct Fick cardiac output were made in the control period, during shock, during norepinephrine infusion, and following discontinuation of norepinephrine. Both cardiac output and peripheral resistance increased during the infusion of norepinephrine.