Sudden death rates were lowest in patients treated with ICDs compared with drug treatment or no antiarrhythmic treatment. However, although ICDs reduced sudden death in selected high-risk patients with severe left ventricular dysfunction, the effect on long-term survival was limited, principally by high nonsudden death rates.
The capability of stroma-free hemoglobin solutions to act as a plasma expander with oxygen and carbon dioxide transport properties has encouraged the idea of their possible use in settings of massive blood loss. Using a canine hemorrhagic shock model (systolic arterial pressure < or = 50 torr for 60 min), we evaluated the efficacy of an ultra-pure stroma-free bovine hemoglobin solution (PBHg) as a resuscitation fluid in hypovolemic and acidotic animals, using homologous blood (PRBC) and 10% human serum albumin (HSA) as control solutions. Following volume replacement, dogs were studied for 2 h under anesthesia and for 4 h subsequently while awake. Resuscitation with PBHg (30 +/- 3 ml/kg) was able to restore stable hemodynamics and correct acidosis to an extent comparable to that in animals treated with PRBC. Additionally, oxygen transport was maintained at a higher level than that in dogs treated with HSA. Administration of PBHg in this shock model revealed no significant cardiopulmonary toxicity or adverse effects. These short-term results suggest that PBHg may be useful for effective resuscitation after major blood loss.
The effects of stroma-free hemoglobin (SFHgb) on the coronary circulation remain unclear. An intact canine model utilizing intracoronary adenosine to abolish the confounding effect of autoregulation was used to study maximal myocardial oxygen delivery during progressive hemodilution with polymerized bovine SFHgb. The circumflex coronary artery was instrumented with a flow probe, hydraulic constrictor, and proximal and distal catheters for adenosine infusion and distal pressure measurement, respectively. This preparation was used to generate diastolic coronary pressure-flow relations during maximal vasodilation. Maximal coronary conductance and maximal myocardial oxygen delivery were determined in two groups of 7 dogs each following hemodilution, first with 6% hetastarch (Control), followed by further hemodilution with ultra-pure, polymerized, bovine SFHgb. After hemodilution with SFHgb, maximal coronary flow increased slightly without evidence of coronary vasoconstriction. Since hemodilution with this material increases oxygen carrying capacity, maximal oxygen delivery is greater than Control, despite the very low canine hematocrit. These findings suggest: 1) SFHgb can provide adequate oxygen delivery to the myocardium despite extreme degrees of hemodilution, and 2) in this intact model, there is no evidence of adverse coronary vasomotion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.