HEMODILUTION

Last update: 04/24/2009
 

Microcirculatory effects of intravenous fluids in critical illness: plasma expansion beyond crystalloids and colloids. Curr Opin Anaesthesiol. 2009 Apr;22(2):163-167. Use of viscous plasma expanders in experimental models of extreme hemodilution, hemorrhagic shock and endotoxemia shows that the limiting factor in anemia is not oxygen-carrying capacity but the decline of microvascular function due to the lowering of functional capillary density. In support of this hypothesis, we find that viscogenic colloids including high-molecular-weight starches, dextrans, polyvinylpyrrolidone, keratin and polyethylene glycol-conjugated albumin maintain or restore microvascular function in extreme hemodilution, polyethylene glycol-conjugated albumin yielding the best results.  Preclinical studies show that polyethylene glycol-conjugated albumin at concentrations in the range of 2-4% extends the transfusion trigger, providing the more extended and complete microvascular and systemic recovery from hemorrhagic shock, extreme hemodilution and endotoxemia, postponing the need of reestablish intrinsic blood oxygen-carrying capacity to hemoglobin concentrations lower than those associated with accepted transfusion triggers.

Acute normovolemic hemodilution.Surg Infect (Larchmt). 2005;6 Suppl 1:s9-s15. Acute normovolemic hemodilution achieves equivalent outcomes at lower cost compared with autologous pre-donation. Patient safety is increased, and if pharmacologic strategies are combined with acute normovolemic hemodilution, allogeneic blood transfusion may be eliminated entirely.

A Prospective Randomized Trial of Acute Normovolemic Hemodilution Compared to Standard Intraoperative Management in Patients Undergoing Major Hepatic Resection.

Ann Surg. 2008 Sep;248(3):360-369. For patients undergoing major liver resection, ANH is safe, effectively reduces the need for allogeneic transfusions, and should be considered for routine use. Given the modest transfusion rate in the STD arm, future efforts should attempt to target ANH use to patients most likely to benefit.

Acute normovolaemic haemodilution with crystalloids in coronary artery bypass graft surgery: a preliminary survey of haemostatic markers.

Acta Cardiol. 2008 Jun;63(3):335-9.ANH reduced the need for PRBC and FFP by 58% and 74%, respectively. Regarding the increase in PT and decrease in Plt count, we concluded that performing ANH with saline solution (SS) in patients undergoing CABG surgery may cause a non-clinically significant change in coagulation state.

The effects of hydroxyethyl starch 130/0.4 (6%) on blood loss and use of blood products in major surgery: a pooled analysis of randomized clinical trials.

Anesth Analg. 2008 Aug;107(2):382-90. Blood loss and transfusion requirements can be significantly reduced in major surgery when using third generation HES 130/0.4 (Voluven) compared to second generation waxy maize starch HES 200/0.5. Since HES 130/0.4 and HES 200/0.5 were found similar regarding volume efficacy in other studies, HES 130/0.4 is recommended in this clinical setting.

Hydroxyethyl starch versus ringer solution in cardiopulmonary bypass prime solutions.

J Cardiothorac Surg. 2008 Jul 12;3(1):45. [Epub ahead of print] In this study, it was shown that the usage of HES 130-0.4 as a prime solution did not have negative effect on postoperative INR level, platelet count, the need for transfusion and the amount of drainage, despite the negative opinions that similar solutions caused coagulation disorders. Another interesting result of the study was that blood platelet count at 24th hour was statistically significantly higher in group treated with HES.. HES 130-0.4 solution is an alternative colloidal solution which can be used as the prime solution or as a mixture with the crystalloids in cardio-pulmonary bypass applications.

Acute normovolemic haemodilution for management of blood loss during radical prostatectomy.

Bratisl Lek Listy. 2008;109(3):144-6. This study demonstrated the effectiveness and safety of ANH as a method for avoiding the allogeneic blood transfusion in patients undergoing radical prostatectomy

The promise of next generation colloids.

Crit Care. 2008 May 14;12(3):147. [Epub ahead of print] The aim of perioperative haemodilution is to reduce loss of red blood cells during elective surgery. The oncotic and molecular characteristics of the various plasma substitutes employed determine how effectively normovolaemia is maintained, and their non-oncotic effects include alterations in microvascular perfusion. PEGylated albumin is superior to hydroxyethyl starch, as reflected by survival, haemodynamic parameters and assessment of the microcirculation using intravital microscopy.
Bloodless spinal surgery: a review of the normovolemic hemodilution technique.
Surg Neurol. 2008 Apr 17; [Epub ahead of print] This study reviews how NH may be safely and effectively used by spinal surgeons, particularly for those who perform multilevel lumbar laminectomies with or without fusion.
Survival time in severe hemorrhagic shock after perioperiative hemodilution scenario with polyethylene glycol conjugated human serum albumin is longer than with HES 130/0.4: a microvascular perspective.
Crit Care. 2008 Apr 18;12(2):R54 [Epub ahead of print] PEG-Albumin's ability to prolong maintenance of microvascular function better than Voluven is a finding that would be significant in a clinical setting involving preoperative blood management and extreme blood loss.
Characterization of the coagulation deficit in porcine dilutional coagulopathy and substitution with a prothrombin complex concentrate.
Anesth Analg. 2008 Apr;106(4):1070-7 Dilutional coagulopathy produced a generalized decrease in coagulation factors and impaired platelet function. Substitution with PCC effectively normalized coagulation and significantly improved hemostasis after venous and arterial bleeding.
Acute perioperative normovolaemic haemodilution in major maxillofacial surgery.
Br J Oral Maxillofac Surg. 2008 Mar 3; [Epub ahead of print] The purpose of this study was to compare a group of patients having major head and neck operations who had APNH, with a historical group, to assess the need for allogeneic transfusion. Of the 21 patients who had APNH only one patient required allogeneic blood. In the historical group of 24 patients, 15 patients had required allogeneic blood (p=0.0001). APNH is an economic, safe and practical way of saving blood.

The effect of acute normovolaemic haemodilution on blood gas parameters: a case report.

Adv Ther. 2008 Feb 28; [Epub ahead of print] After induction of general anaesthesia, 1600 ml of blood was collected and replaced with an equal volume of 6% hexaethyl starch. Results: Haemoglobin and haematocrit concentrations were significantly lower following haemodilution (14.9 and 9.2 g/dl for haemoglobin versus 45.0% and 31.7% for haematocrit). There was no significant change in the heart rate, blood pressure or end-tidal carbon dioxide tension throughout the operation period. Central venous pressure increased marginally from 5 to 90 min, but was within normal limits. There was no significant change in blood gas parameters following haemodilution. Platelet count decreased following haemodilution but the values were within normal limits. Conclusion: Acute normovolaemic haemodilution with 6% hexaethyl starch is a safe procedure for blood conservation in selected operations. It did not cause any haemodynamic or blood gas parameters to change. It did not have any adverse effect on haemostatic mechanisms that could enhance the risk of bleeding at surgery.

Effect of restrictive fluid management and acute normovolemic intraoperative hemodilution on transfusion requirements during living donor hepatectomy.

Transplant Proc. 2008 Jan-Feb;40(1):224-7. A restrictive fluid management strategy with acute normovolemic intraoperative hemodilution was a safe blood-salvage technique for living-donors for liver transplantation. This approach was also associated with decreased length of hospital stay and a trend toward decreased transfusion requirements.

Hemodilution and anemia in patients with cardiac disease: what is the safe limit?

Curr Opin Anaesthesiol. 2008 Feb;21(1):66-70. The absolute lowest threshold for anemia in patients with cardiac disease cannot be established. Further studies are needed to develop evidence-based transfusion guidelines for these patients. Rather than primarily focusing on transfusion, physicians should first administer therapies that have been shown to improve outcome. In the setting of coronary artery disease, control of heart rate appears of paramount importance.

Clinical relevance of the effects of plasma expanders on coagulation.

Semin Thromb Hemost. 2007 Nov;33(8):810-5. Most plasma expanders have marked effects at various points in the hemostatic system and that there are significant differences between various plasma replacement fluids but that clinically relevant effects on bleeding are mostly present if large volumes (i.e., > 1.5 L) are infused or if the patient has a concomitant or preexistent hemostatic impairment.

Perioperative hemodilutional autologous blood transfusion in burn surgery.

Injury. 2007 Nov 28; [Epub ahead of print] Perioperative haemodilutional autologous blood transfusion is considered applicable in burn surgery. This study evaluates the effectiveness of the technique in the treatment of burns.

Hydroxyethyl starch: the effect of molecular weight and degree of substitution on intravascular retention in vivo.
Anesth Analg. 2007 Sep;105(3):724-8. HES-B and HES-C are equally retained in the blood vessels. Middle-sized HES-B with low DS and middle substitution pattern stayed in the blood vessels as long as the large-sized HES. HES solutions of varying characters should be examined to optimize HES infusion.

Pulmonary function is better preserved in pigs when acute normovolemic hemodilution is achieved with hydroxyethyl starch versus lactated ringer's solution.
 Shock. 2007 Apr;27(4):390-396. In this kind of experimental model, ANH with 6% HES (200/0.5) seems to preserve lung structure better as evidenced by maintenance of oxygenation indexes and respiratory compliance when compared with that in the Ringer's solution hemodiluted group.

Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement.
Transfusion. 2007 Feb;47(2):341-50. Besides conventional cardiac preservation techniques, preoperative ANH further attenuates myocardial injuries. Optimization of preischemic myocardial oxygen delivery and/or consumption and the postconditioning effects of endogenous EPO are potential mechanisms for ANH-induced cardioprotection.

Cardioprotective effects of acute normovolemic hemodilution in patients undergoing coronary artery bypass surgery.
Chest. 2005 Aug;128(2):838-47. In addition to conventional myocardial preservation techniques, preoperative ANH achieved further cardiac protection in patients undergoing on-pump myocardial revascularization. FULL TEXT