Epinephrine Versus Dopamine to Treat Shock in Hypoxic Newborn Pigs Resuscitated With 100% Oxygen

Abstract

Shock and tissue hypoperfusion are common after asphyxia. We compared systemic and regional hemodynamic effects of epinephrine and dopamine in the treatment of shock and hypotension in asphyxiated newborn piglets resuscitated with 100% oxygen. Twenty-four piglets (1-3 days old; weight, 1.4-2.6 kg) were acutely instrumented to measure cardiac index (CI), carotid, mesenteric and renal arterial blood flows, and mean systemic (SAPs) and pulmonary arterial pressures (PAPs). Piglets had normocapnic alveolar hypoxia (F(IO2)=0.08-0.10) for 50 min and reoxygenated with F(IO2)=1.0 for 1 h then F(IO2)=0.21 for 3.5 h. After 2 h reoxygenation, either dopamine (2 microg kg(-1) min(-1)) or epinephrine (0.2 microg kg(-1) min(-1)) was given for 30 min in a blinded randomized manner, which was then increased to maintain SAP (within 10% of baseline, pressure-driven dose) for 2 h. Hypoxia caused hypotension (SAP, 44%+/-3% of baseline), cardiogenic shock (CI, 41%+/-4%), and metabolic acidosis (mean pH, 7.04-7.09). Upon reoxygenation, hemodynamic parameters immediately recovered but gradually deteriorated during 2 h with SAP at 45+/-1 mmHg, CI at 74+/-9% of baseline, and pH 7.32+/-0.03. Low doses of either drug had no significant systemic and renal hemodynamic response. Epinephrine (0.3-1.5 microg kg(-1) min(-1)) for 2 h increased SAP and CI (with higher stroke volume) and decreased pulmonary vascular resistance (with reduced PAP-SAP ratio), whereas the responses with dopamine (10-25 microg kg(-1) min(-1)) were modest. Low-dose epinephrine improved mesenteric and carotid arterial flows, whereas the pressure-driven doses of epinephrine and dopamine increased carotid and mesenteric arterial flows, respectively. To treat shock in asphyxiated newborn piglets resuscitated with 100% oxygen, epinephrine exhibits an inotropic action compared with dopamine, whereas both catecholamines can increase carotid and mesenteric perfusion.

Dopamine infusion for postresuscitation blood pressure support after profound asphyxia in near‐term fetal sheep

“…Although dopamine has traditionally been suggested to raise pressure through inotropic effects at low doses and through pressor effects at higher doses (Evans, 2006), the evidence for this is mixed. In short‐term studies in newborn piglets after hypoxia, dopamine typically had little effect on systemic vascular resistance (Barrington et al 1995; Cheung & Barrington, 2001) but increased MAP modestly (Obaid et al 2008; Joynt et al 2010), suggesting a primarily cardiac effect at doses of up to 20 μg kg −1 min −1 .…”

“…Early clinical studies suggested that low‐dose dopamine (2.5 μg kg −1 min −1 ) was associated with increased contractility and systolic blood pressure in severely asphyxiated neonates (DiSessa et al 1981), with primarily vasopressor actions at higher doses (Seri & Evans, 2001). In newborn piglets exposed to acute hypoxia followed by hyperoxia, infusion of dopamine (and other related inotropic agents, including adrenaline, dobutamine and milrinone) can acutely increase arterial blood pressure and perfusion of key organs for several hours, primarily by increasing cardiac output, consistent with primarily inotropic effects (Barrington et al 1995; Cheung & Barrington, 2001; Obaid et al 2008; Joynt et al 2010). It is unknown whether these benefits are persistent.…”

A comparison of combination dopamine and epinephrine treatment with high-dose dopamine alone in asphyxiated newborn piglets after resuscitation

“…Other than dopamine, epinephrine is commonly used in neonatal intensive care units. A significant improvement of cardiac function has been observed after administration of epinephrine in various asphyxiated newborn porcine models ( 9 , 10 ). Clinically, epinephrine has been shown as effective as dopamine for the treatment of hypotension in low-birth-weight infants ( 11 ).…”

Not All Models Are Created Equal: Animal Models to Study Hypoxic-Ischemic Encephalopathy of the Newborn

“…In addition to its vasoregulatory effect on the cerebral circulation, the effect of CO 2 on myocardial injury following reoxygenation has been shown by Borke et al [13] . Nevertheless, the animals are usually critically ill with the features of clinical asphyxia, such as shock, hypotension and multi-organ dysfunction or failure [14] .…”