Quarterly Literature Update
The following contains the quarterly summary of peer-reviewed publications related “exclusively” to ANH for the months of July to September 2006, (and a few publications missed during the prior quarter) taken from the National Library of Medicine databases. My commentary (italics) may be added to reports of special import. NLIM now lists abstracts before they are formally published, as “Epubs.” For simplicity, Epubs are listed separately.
Bennett J et al: Acute normovolemic hemodilution in moderate blood loss surgery: a randomized controlled trial. Transfusion, Volume 46, pages 1097-1103. (PMID: 16836555) Patients undergoing elective hip surgery wee randomized to either ANH or a standard transfusion group. Blood transfusion requirements did not differ significantly between groups. However, infective complications were lower in the ANH group.
Cabrales P et al: Blood viscosity maintains microvascular conditions during normovolemic anemia independent of blood oxygen-carrying capacity. American Journal of Physiology Heart and Circulatory Physiology, Volume 291, pages H581-590. (PMID: 16517943) Another hamster window microcirculation study from this prolific group in which effects of ANH on viscosity and oxygen delivery were studied. In this study, decreased microcirculatory conditions associated with ANH were secondary to decreased viscosity, not decreased oxygen delivery.
Epstein NE et al: Impact of intraoperative normovolemic hemodilution on transfusion requirements for 68 patients undergoing lumbar laminectomies with instrumented posterolateral fusion. Spine, Volume 31, pages 2227-2230 with discussion on page 2231. (PMID: 16946658) The effect of ANH on allogeneic transfusion was studied in patients undergoing extensive spine surgery. The majority of patients required no allogeneic blood, although this study is seriously flawed from a methodological standpoint.
Farina JA et al: Comparative study of isovolemic hemodilution with 3% albumin, dextran-40, and prophylactic enoxaparin (LMWH) on thrombus formation at venous microanastomosis in rats. Microsurgery, Volume 26, pages 456-464. (PMID: 16924631) A rodent study that compared ANH with albumen or dextran with fractionated heparin in reducing thrombus formation in venous anastomosis. ANH with albumen was the most effective antithrombotic agent.
Han SH et al: The effect of esmolol-induced controlled hypotension in combination with acute normovolemic hemodilution on cerebral oxygenation. Acta Anaesthesiologica Scandinavica, Volume 50, pages 863-868. (PMID: 16879470) The effect of ANH and controlled hypotension on cerebral oximetry was studied in patients undergoing orthopedic surgery. Controlled hypotension plus ANH was associated with lower regional oxygen saturation indices compared to ANH alone.
Huang Y et al: PEGylated albumin-heme as an oxygen-carrying plasma expander: Exchange transfusion into acute anemia rat model. Biomaterials, Volume 27, pages 4477-4483. (PMID: 16678256) A study in rats using ANH to simulate a hemorrhagic state, examined the effect of a novel PEgylated albumen heme on various parameters of oxygen transport. The PEGylated solution functioned as an effective oxygen-carrying plasma expander.
Jabbour N et al: Impact of a transfusion-free program on non-Jehovah's Witness patients undergoing liver transplantation. Archives of Surgery, Volume 141, pages 913-917. (PMID: 17001788) Since the inception of the transfusion-free liver transplantation program at USC – LA, 239 orthotopic liver transplants were performed. Compared to an earlier control group, the transfusion-free program has reduced allogeneic transfusion rates.
Loubser PG: Needleless adaptation to blood collection bags used for acute normovolemic hemodilution. Anesthesia Analgesia, Volume 103, pages 491-492. (PMID: 1686144) Letter describing a modification of blood collection bags used for ANH.
Mathru M et al: Splanchnic oxygen consumption is impaired during severe acute normovolemic anemia in anesthetized humans. Anesthesiology, Volume 105, pages 37-44. (PMID:16809992) They induced ANH to a Hb of 6 g/dl, in patients undergoing spine or abdominal surgery, studying several parameters of splanchnic oxygen delivery and consumption. Splanchnic oxygen consumption was impaired and oxygen delivery decreased, suggesting that the risk to the GI tract during ANH is substantial.
Morariu AM et al: Acute isovolemic hemodilution triggers proinflammatory and procoagulatory endothelial activation in vital organs: role of erythrocyte aggregation. Microcirculation, Volume 13, pages 397-409. (PMID: 16815825) A porcine study examining erythrocyte aggregation and endothelial activation during ANH. Erythrocyte aggregation was reduced during ANH. The findings suggest an endothelium-dependent thrombogenic response may occur in the microcirculation during ANH.
Ramnarine IR et al: Autologous blood transfusion for cardiopulmonary bypass: effects of storage conditions on platelet function. Journal of Cardiothoracic and Vascular Anesthesia, Volume 20, pages 541-547. (PMID: 16884986) Platelet function (impedance aggregometry) of ANH blood stored in citrate or heparinized blood bags at room temperature was studied in 27 patients undergoing CABG surgery. Platelet function was reduced by storage in both agents, although more with heparin. Even after reinfusion, platelet function in vivo was reduced. The authors conclude that ANH whole blood should not be stored in citrate. Scharbert et al, Anesth Analg, Volume 102, pages 1280-4, 2006, reported that platelets stored at room temperature were associated with marked inhibition of platelet aggregation. This effect was absent when platelets were stored near 37oC. So, are Ramnarine’s findings secondary to temperature, citrate, heparin or both?
Ruttmann TG et al: The haemodilution enhanced onset of coagulation as measured by the thrombelastogram is transient. European Journal of Anaesthesiology, Volume 23, pages 574-579. (PMID: 16507197) Volunteers were subjected to hemodilution by rapidly infusing crystalloid. TEG showed faster onset of coagulation, while antithrombin levels decreased.
Shander A et al: The long and winding road of acute normovolemic hemodilution. Transfusion, Volume 46, pages 1075-9. (PMID: 16836551) An editorial comment on the study by Bennett et al, above, in the same Journal.
Sharma V et al: Evaluation of Epsilon amino-caproic acid (EACA) and autologous blood as blood conservation strategies in patients undergoing cardiac surgery. Heart, Lung and Circulation, Volume 15, 261-265. (PMID: 16698318) They compared two groups of patients undergoing cardiac surgery. ANH was performed in one group while EACA was used in the other. No difference was found between groups with respect to allogeneic transfusion. However, this study is seriously flawed from a methodological standpoint.
Verdin-Vasquez RC et al : Use of perftoran emulsion to decrease allogeneic blood transfusion in cardiac surgery: clinical trial. Artificial Cells Blood Substitutes Immobilization Biotechnology, Volume 34, pages 433-454. (PMID: 16818416) The PFC perftoran was used in conjunction with ANH in 30 patients undergoing cardiac surgery. Compared to controls, the Perftoran patients manifested a higher PaO2 and required less allogeneic blood
AI
