Quarterly Literature Update

The following contains the quarterly summary of peer-reviewed publications related “exclusively” to ANH for the months of April to June 2008 (and possibly a few publications missed during the prior quarters) 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.

Anon: Blood-sparing techniques in pediatric neuroanesthesiology. Anesteziol Reanimatol 2:22-6. (PMID: 18543425) This article reports the effect of various blood conservation tools in 89 patients undergoing neurosurgery. They conclude that ANH and autotransfusion are the “summation” of blood sparing effects.

Casati V et al: Complex cardiac surgery in Jehovah's Witnesses with chronic renal failure. J Cardiothorac Vasc Anesth 22:453-4. (PMID: 18503941) The authors describe 2 JW patients with chronic renal failure undergoing complex cardiac surgery, using their blood conservation protocol (which included ANH).

Erol DD et al: The effect of acute normovolaemic haemodilution on blood gas parameters: a case report. Adv Ther 25:148-51. (PMID: 18311548) This article was reviewed in ANH Bulletin #95.

Gal R: Acute normovolemic haemodilution for management of blood loss during radical prostatectomy. Bratisl Lek Listy 109:144-6. (PMID: 18517140) In this study, 15 patients undergoing radical prostatectomy also received ANH as a blood conservation tool. Only 2 patients required 1 unit of allogeneic blood.

Haas T et al: The in vitro effects of fibrinogen concentrate, factor XIII and fresh frozen plasma on impaired clot formation after 60% dilution. Anesth Analg 106:1360-5. ROTEM was used to assess the effects of hemodilution on coagulation parameters in this in vitro blood study. At 60% hemodilution, supplementation with fibrinogen restored all abnormal ROTEM values (but not Factor XIII.) (PMID: 18420845)

Imai Y et al: Isovolaemic haemodilution decreases the shivering threshold in rabbits. Eur J Anaesthesiol 25:450-3. (PMID: 18339218) This article was reviewed in ANH Bulletin #95.

Joubert KE: Acute normovolaemic haemodilution--is it a solution to reduce perioperative blood transfusions? J S Afr Vet Assoc 78:188-94. (PMID: 18507216) A review article on ANH, with special relevance to animals.

Kheirabadi BS et al: Effects of synthetic versus natural colloid resuscitation on inducing dilutional coagulopathy and increasing hemorrhage in rabbits. J Trauma 64:1218-28; discussion 1228-9. (PMID: 18469644) In this rabbit study, 40% hemodilution was achieved using either hextend, dextran or albumen for fluid replacement. The albumen group was associated with increased survival and better coagulation parameters.

Li LY et al: Effect of acute progressive normovolemic hemodilution with lactated Ringer's, gelatin and hydroxyethyl starch on coagulation and survival rate in rabbits. Beijing Da Xue Xue Bao 40:292-300. (PMID: 18560458) This complex study sought to compare the effects of various hemodilution strategies on coagulation function both in vitro and in vivo. LR, HES or gelatin were used for ANH. The main result was that in vivo ANH was associated with no change or an acceleration of coagulation function, in contrast to in vitro hemodilution.

Loubser PG et al: Case 3 – 2008: The use of acute normovolemic hemodilution during cardiac surgery in a patient with human immunodeficiency virus infection. Journal of Cardiothoracic and Vascular Anesthesia, 22:474-81. (PMID: 18503944) The authors describe a patient with HIV infection undergoing cardiac surgery with ANH. The implications of performing such a modality in HIV positive patients are discussed.

Nagy CJ et al: Acute normovolemic hemodilution, intraoperative cell salvage and PulseCO hemodynamic monitoring in a Jehovah's Witness with placenta percreta. Int J Obstet Anesth 17:159-63. (PMID: 18308549) This article was reviewed in ANH Bulletin #95.

Parkin IR et al: Acute perioperative normovolaemic haemodilution in major maxillofacial surgery. Br J Oral Maxillofac Surg 46:387-90. (PMID: 18321618) This article was reviewed in ANH Bulletin #95.

Rahman IA et al: Thoraco-abdominal aneurysm repair in a Jehovah's Witness: Maximizing blood conservation. Perfusion 22:363-4, 2007. (PMID: 1841622) A case report is described in which a JW patient undergoing TAAA repair using a blood conservation protocol is described.

Yang ZJ et al: The effect of isovolemic hemodilution with Oxycyte , a perfluorocarbon emulsion, on cerebral blood flow in rats. PLoS ONE 3:e2010. (PMID: 18431491) In this study, regional cerebral blood flow was measured during ANH with either albumen or perfluorocarbon. The perfluorocarbon group manifested more stable cerebral blood flow, as well as higher oxygen content in arterial blood.

Xiong L et al: Acute normovolaemic haemodilution with a novel hydroxyethyl starch (130/0.4) reduces focal cerebral ischaemic injury in rats. Eur J Anaesthesiol 25: 581-8. (PMID:18413007) In this rat study, the neuroprotective effect of ANH with a new starch formulation, HES130/0.4 was studied. Rats undergoing ANH were subjected to middle cerebral artery ligation, and infract size measured. Use of the new HES to a hematocrit of 25-30% was associated with improved neurological outcome.

Epubs

Dahaba AA et al: Influence of acute normovolaemic haemodilution on bispectral index monitoring and propofol dose requirements. Acta Anaesthesiol Scand, May 12. (PMID: 18477087) They compared the effect of ANH and a propofol infusion on the BIS in subjects exposed to oxygen or air. ANH enhanced the effect of propofol on the BIS during induction; however, there were no other changes.

Lundby C et al: Does recombinant human epo increase exercise capacity by means other than augmenting O2 transport? J Appl Physiol Jun 5. (PMID: 18535134) In this fascinating study, 8 subjects were treated with recombinant epoetin alfa for 13 weeks. They were then subjected to ANH to the Hb level prior to epoetin treatment. Exercise studies of leg and muscle oxygen uptake were performed at various steps. Oxygen delivery was augmented by epoetin secondary to increased muscle oxygen delivery, but not increased cardiac output.

Pape A et al: Improved short-term survival with polyethylene glycol modified hemoglobin liposomes in critical normovolemic anemia. Intensive Care Med Apr 2. (PMID: 18385978) In this study, dogs subjected to a critical level of ANH received either saline or a liposome-encapsulated Hb substitute. The Hb substitute was associated with prolonged survival and hemodynamic stability.

June Scientific Meetings

The 30th Annual Meeting of the SCA convened this month in Vancouver, Canada. Unfortunately, there were no abstract presentations related to ANH – in recent years, research related to blood management seems to be waning at this meeting.

The 23rd Annual Meeting of the European Association of Cardiothoracic Anaesthesiologists also convened this month in Antalya, Turkey. Their abstracts are now published in the Journal of Cardiothoracic and Vascular Anesthesia and online at www.jcvaonline.com. There was one abstract related to ANH as follows;

O-04 – Aghadavoudi O, Ostovan J: Assessment of the haematological and haemodynamic influence of colloid and crystalloid solutions in acute normovolaemic haemodilution in coronary artery bypass grafting surgery. They computed the effect of fluid replacement with either colloid or crystalloid in 60 patients undergoing CABG surgery. Although they do not describe their blood collection protocol, they report that the transfusion or requirement for allogeneic blood was significantly less in the colloid group. (JCTVA, Volume 23, C31, Supplement.)

Intellectual Property Update – The HBS Nomogram

Intellectual property updates are designed to inform readers of any new technologies or inventions that are in the pipeline, as it were. The USPTO website is a verifiable treasure trove of ideas and concepts and the source of some of these updates.

I recently came across a fascinating but lengthy patent that presents a new method of evaluating blood volume and measuring response to allogeneic blood transfusion.

The patent is currently in the examination process, but is now published on the USPTO website under number 20070178167. Titled “Systems and Method for Homeostatic Blood States (HBS),” the patent is authored by Audrius Andrijauskas from Vilnius in Lithuania.

The key element in this invention is the HBS Nomogram, shown below. The nomogram guides the transfusion of packed RBCs, and analyzes several variables including ideal blood volume, target red cell mass and a constant ‘k.’ An Osmonomogram is also presented which defines tables of normal mean cell hemoglobin content, mean cell volume, and mean cell hemoglobin concentration. The invention claims that this method can be used to guide intravenous fluid therapy and even treat dehydration and can be incorporated into an apparatus that actually calculates these variables.

In presenting this invention, Andrijauskas reviews the current limitations of existing art. First, current methods or estimates or total blood volume are reported as being inaccurate. Estimates of what is termed the “exchangeable blood volume” such as for e.g. during ANH, are also thought to be less than the actual total blood volume. The inventor describes the dangers of performing ANH based on these calculations. Blood compartment models are presented that account for tissue perfusion, tissue osmolarity and blood equilibrium.

The invention also claims that it has major relevance to patients undergoing surgery with blood loss, requiring a packed RBC blood transfusion. This work makes fascinating if not confusing reading, since many of the physiologic principles that are currently mainstream seem challenged in this work. However, the theory of the HBS Nomogram seems applicable to software and/or microprocessors, and we may see it incorporated into some new technology in the future.