Document Detail


The hemodynamic effects of dobutamine during reoxygenation after hypoxia: a dose-response study in newborn pigs.
MedLine Citation:
PMID:  17545944     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Asphyxiated neonates usually have myocardial stunning and hypotension and require inotropic support. A randomized controlled study was designed to examine the dose-response effect of dobutamine (5-20 microg x kg(-1) x min(-1)) on systemic and regional circulations and oxygen metabolism in a neonatal swine model of hypoxia/reoxygenation. Thirty-eight anesthetized newborn piglets were acutely instrumented for continuous monitoring of heart rate, systemic and pulmonary arterial pressures, and pulmonary (surrogate for cardiac index), right common carotid, and superior mesenteric and left renal arterial flows. After stabilization, they were exposed to normocapnic alveolar hypoxia (10%-15% oxygen) for 2 h followed by reoxygenation with 100% oxygen for 1 h, then 21% for 3 h. Piglets were block randomized to receive dobutamine infusion (5, 10, or 20 microg x kg(-1) x min(-1)) or saline (control) at 2 to 4 h of reoxygenation (n = 8 each). A nonasphyxiated, sham-operated group was included (n = 6). Blood samples were collected for blood gas analysis, arterial and venous co-oximetry, and plasma lactate concentration determination. At 2-h reoxygenation after hypoxia, there was hypotension (systemic arterial pressure, 27 to 36 mmHg) and myocardial dysfunction (cardiac index from 178-209 to 134-156 mL x kg(-1) x min(-1)). Cardiac index improved significantly with 20 microg x kg(-1) x min(-1) of dobutamine (P < 0.05) and modestly in the treatment groups of 5 and 10 microg x kg(-1) x min(-1) (P < 0.1) (at 120 min, 172 +/- 35, 160 +/- 30, and 158 +/- 56 mL x kg(-1) x min(-1) vs. 119 +/- 33 mL x kg(-1) x min(-1) of controls, respectively), with corresponding increases in stroke volume. Pulmonary vascular resistance was lower in all dobutamine-treated groups (vs. controls, P < 0.05) There were no differences in heart rate, systemic and pulmonary arterial pressures, systemic vascular resistance, and regional flows between groups. The group of 20 mug.kg.min of dobutamine also had higher systemic oxygen delivery (at 120 min, 18 +/- 5 vs. 11 +/- 3 O(2) mL x kg(-1) x min(-1) of controls, P < 0.05) with no significant differences in systemic oxygen consumption and regional oxygen delivery between groups. After the reoxygenation of newborn piglets with severe hypoxia, high dose of dobutamine is effective to treat myocardial stunning and low cardiac output with no significant effect on blood pressure or regional circulation. Further clinical studies are needed to confirm these findings in the human neonate.
Authors:
Zakariya Al-Salam; Scott Johnson; Sameh Abozaid; David Bigam; Po-Yin Cheung
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Shock (Augusta, Ga.)     Volume:  28     ISSN:  1073-2322     ISO Abbreviation:  Shock     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-08-28     Completed Date:  2007-10-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9421564     Medline TA:  Shock     Country:  United States    
Other Details:
Languages:  eng     Pagination:  317-25     Citation Subset:  IM    
Affiliation:
Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn
Anoxia / drug therapy,  physiopathology*
Asphyxia Neonatorum / drug therapy*,  physiopathology
Blood Pressure / drug effects
Cardiac Output / drug effects
Dobutamine / administration & dosage*,  therapeutic use
Dose-Response Relationship, Drug
Heart Rate / drug effects
Humans
Infant, Newborn
Lactic Acid / blood
Oxygen / therapeutic use*
Stroke Volume / drug effects
Swine
Vascular Resistance / drug effects
Chemical
Reg. No./Substance:
34368-04-2/Dobutamine; 50-21-5/Lactic Acid; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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