Acute normovolemic hemodilution.

This article examines the technique of hemodilution and the consequences, benefits, efficacy, cost effectiveness, and future of acute normovolemic hemodilution.

Modern concepts of autologous haemotherapy.

The increasing current perception that the safety of allogeneic blood transfusion has dramatically been improved during the last decade is challenging autologous haemotherapy methods. In addition, growing concern about the unfavourable cost-effectiveness of most autologous haemotherapy methods requires a refinement of the application of these measures to well defined circumstances. In contrast, newly emerging transfusion-transmissible infections or periods of blood shortage might revive interest in these blood sparing techniques. Preoperative autologous blood donation still plays a significant role in settings with high individual benefit for the patient, high transfusion probabilities and when all opportunities of cost minimization can be applied. Preoperative plasmapheresis is considered to be a sensible adjunct if intraoperative retransfusion of salvaged and washed red cells is planned. Acute normovolaemic haemodilution is valuable when the patient's tolerability of the haemodilution and the expected blood loss are carefully examined beforehand. Intra- or postoperative salvage of wound blood can also be regarded as useful measures to prevent allogeneic transfusions as long as the specific advantages and disadvantages of the different methods are taken into account. Finally, alternative and supplemental measures such as iron or erythropoietin administration should always be considered in order to optimize the efficacy and effectiveness of autologous haemotherapy methods. The goal of a "bloodless medicine" might not be reached but is supposed to be approached closely with an integrated concept exploiting all measures available. However, in times of restricted health care resources, regular sound cost-effectiveness analyses, taking the availability and the current safety profile of allogeneic blood products into account, are always warranted and needed.

Effects of standardized acute normovolemic hemodilution on intraoperative allogeneic blood transfusion in patients undergoing major maxillofacial surgery.

The aim of the present study was to demonstrate the practicality and efficacy of acute normovolemic hemodilution (ANH) to reduce allogeneic red blood cell (RBC) transfusion in patients undergoing elective surgery with anticipated high intraoperative blood loss (BL). 124 patients (age 48 +/- 18 years, ASA classes I-III) underwent major maxillofacial surgery in a university hospital (68% tumor surgery, 32% dysgnathia correction). After induction of general anesthesia, ANH was performed by standardized withdrawal of 900 ml (2 units) of whole blood and simultaneous infusion of 500 ml of hydroxyethyl starch solution (6% HES 130,000/0.4) and 1500 ml of crystalloidal solution. Intraoperative BL was fluid-compensated until physiologic parameters indicated the need for RBC transfusion. First, autologous ANH-blood was retransfused followed by, if necessary, allogeneic RBC. Total BL was referred to the patient's calculated blood volume (BV): fractional blood volume loss, BL(fract) = BL/BV. ANH took 16 +/- 2 min and was void of any adverse event. The costs for ANH was 24 per patient. 55 patients had a mean BL(fract) of 44 +/- 28% and required an intraoperative transfusion; 49/55 patients with an average BL(fract) of 37 +/- 14% were transfused with only autologous ANH-blood; 6/55 patients with a mean BL(fract) of 100 +/- 47% underwent additional transfusion with allogeneic RBC. Standardized, 2 unit, ANH is a practicable, safe and economic blood conservation technique that allowed for the complete avoidance of allogeneic RBC transfusion in 89% of patients undergoing maxillofacial surgery that required an intraoperative RBC transfusion.

[Indications for blood transfusion during orthopedic surgery]. / Indikation zur Bluttransfusion bei orthopädischen Eingriffen.

Ageing of the population increases the number of large orthopedic surgical interventions in elder people. High perioperative blood loss together with a reduced tolerance to anemia increase the transfusion probability in this patient subgroup. The expected cost explosion in the transfusion system (cost intensive quality management, imbalance between the number of donors and recipients) as well as the remaining transfusion related risk of hemolysis, infection and immunosuppression reflect the high socio-economic significance of the development of institutional transfusion programs. The present article summarizes: (1) the (patho-) physiology of anemia compensation, (2) the decision making for transfusion in healthy patients and patients with cardiovascular disease, and (3) the currently applied pre- and intraoperative techniques to reduce allogeneic transfusion in orthopedic patients.

[Rational use of blood cell products in orthopedics and traumatology]. / Rationaler Einsatz von Blutkonserven in Orthopädie und Traumatologie.

STUDY DESIGN: The risk of transmission of human immunodeficiency virus (HIV), hepatitis B and C viruses as well as the development of costs has changed the use of homologous blood cell products. METHODS: The present investigation shows the state of the art of blood salvage in orthopedic and elective trauma surgery. RESULTS: In this investigation the established methods such as controlled hypotension (spine surgery), arrest of blood supply (extremity surgery) and the following methods of autotransfusion have been examined: acute normovolemic hemodilution (ANH), intra- (Cell-Saver, Haemonetics Corp.) and postoperative autotransfusion, autologous donor plasmapheresis and autologous predeposit. CONCLUSIONS: Using this method it is possible to reduce homologous blood transfusions particularly in elective procedures such as orthopedic surgery and elective trauma surgery to a minimum.

[Autologous blood procurement--acute normovolemic hemodilution vs. preoperative autologous blood donation]. / Autologe Blutgewinnung--akute normovolämische Hämodilution vs. präoperative Eigenblutspende.

Autologous blood procurement remains in evolution. Interest in preoperative autologous blood donation (PAD) increased substantially in the 1980's due to the recognition that HIV was transmissible by blood. Concomitant with increased blood safety, however, PAD activity has declined approximately 40% since 1992. Reasons for this decline are unclear; patients may feel more comfortable with issues regarding blood safety, but associated costs and discard rates of up to 50% of blood units are other important factors. An alternate strategy is acute normovolemic hemodilution (ANH), which has the advantages of lower costs along with no wastage of blood units. A further advantage is that since ANH units never leave the patient's bedside, there is no possibility of an administrative error that could lead to ABO-related hemolysis (as could occur with PAD units stored in the blood bank). Concerns regarding the adequacy of national blood inventories may restimulate interest in autologous blood procurement, independent of issues regarding blood risks or costs.

A prospective randomized study comparing two techniques of perioperative blood conservation: isovolemic hemodilution and hypervolemic hemodilution.

UNLABELLED: We compared hypervolemic hemodilution (HVH) and isovolemic hemodilution (IVH) as means of perioperative blood conservation under standardized conditions. Thirty ASA status I/II adults slated for orthopedic, ear-nose-throat, or general surgery with expected blood loss of >500 mL underwent either IVH (n = 15) or HVH (n = 15). They were hemodiluted to a hematocrit (Hct) of 25% by blood withdrawal and simultaneous polygeline (Hemaccel((R))) infusion (IVH) or by infusing polygeline without blood withdrawal, thus creating hypervolemia (HVH). Further blood loss to a Hct of 20% was allowed before autologous/allogeneic blood transfusion to aim for a 24-h postoperative Hct of > or =25%. Systolic blood pressure (P = 0.0107) and central venous pressure (P = 0.0281) were significantly higher during HVH. The mean difference (MD) between the target postdilution Hct of 25% and the Hct achieved was not statistically significant in either group (MD [95% confidence interval; CI], 0% [-0.7% to 0.7%] for IVH and 0.6% [-0.1% to 1.3%] for HVH). The actual amount of allogeneic blood used was similar in the two groups, with an MD (95% CI) of -7 (-326 to 312), and was significantly less than the corresponding projected amount (MD [95% CI], -581 mL [-753 to -409 mL] in IVH; -376 mL [-531 to -221] in HVH). The two techniques were similar in time taken (MD [95% CI] = 7 min [-0.5 to 14.5 min]), cost incurred (MD [95% CI] = $1.7 (-$4.10 to $7.50]), and volumes of polygeline used (MD [95% CI] = -6 mL/kg body weight [-16 to 4 mL/kg body weight]). This study found IVH and HVH comparable in significantly reducing perioperative allogeneic blood requirements, time needed, and cost incurred. The formula used for achieving the desired HVH appears promising. IMPLICATIONS: Both hypervolemic hemodilution (HVH) and isovolemic hemodilution (IVH) claim to reduce red blood cell loss during surgery by diluting the patient's blood. This study found both comparable in significantly reducing the exposure to bank blood in the perioperative period, the time needed, and the cost incurred. HVH, being simpler, because it does not involve blood withdrawal, appeared superior to IVH in the healthy adults studied. Larger studies are needed to substantiate the results.

Perioperative hemodilution.

Acute normovolemic hemodilution (ANH) entails the removal of blood from a patient either immediately before or shortly after induction of anesthesia and the simultaneous replacement with cell-free fluid, preferably synthetic colloids with a predictable volume effect (6% dextran 60/70, 6% hydroxyethyl starch 200,000 and 130.000, respectively). Hemodilution is part of the concept for avoiding or limiting the use of allogeneic blood and should be considered for patients undergoing elective surgery free of contraindications and presenting with an initial hemoglobin concentration > or = 12 g/dl and an anticipated blood loss of > or = 1500 ml. The efficacy of ANH, judged by the necessity to transfuse homologous blood, depends on the preoperative (initial) hematocrit, the target hematocrit (to which hemodilution is performed), and the preset intra- and postoperative transfusion trigger. In the past data from clinical trials have shown that in healthy subjects a target hematocrit of 20-25% (7.0-8.0 g/dl hemoglobin concentration) is feasible and safe for the patient. The lower the target hemoglobin concentration, the more extensive monitoring is required: intraoperative target hemoglobin concentrations of 5.0 g/dl and less have been tolerated by young surgical patients without adverse effects. The safety as well as efficacy of acute normovolemic hemodilution in terms of reducing homologous blood transfusion requirements have been demonstrated in various clinical studies. ANH therefore is regarded an integral part of programs aimed at reducing the need for homologous blood, and can thus be successfully combined with preoperative autologous blood deposition, intraoperative blood salvage and carefully adjusted surgical techniques.

Economic evaluation of a randomized clinical trial of haemodilution with cell salvage in aortic surgery.

BACKGROUND: This study evaluated the costs of acute normovolaemic haemodilution (ANH) and intraoperative cell salvage (ICS) versus homologous blood transfusion in aortic surgery in a prospective multicentre randomized trial. METHODS: One hundred and forty-five patients were randomized either to standard transfusion practice (homologous) or to a combination of ANH and ICS (autologous). Costs for each inpatient admission were identified. Cell salvage costs were assigned on the assumption that 50 operations were done each year employing a trained cell salvage operator. The results were analysed statistically using bias-corrected bootstrap analysis. RESULTS: Patients who had transfusion of homologous blood received some 251 units and those having a homologous transfusion received 103 units (P = 0.008). There was no difference in morbidity, mortality and duration of hospital stay. Transfusion-related mean costs were similar at 340 UK pounds for patients having a homologous transfusion and 357 UK pounds for those receiving autologous blood (mean difference 17 UK pounds (95 per cent confidence interval [c.i.]--184 UK pounds to 174 UK pounds); P not significant). There was also no significant difference in mean overall costs: 5859 UK pounds for homologous and 5384 UK pounds for autologous transfusion (mean difference--475 UK pounds (95 per cent c.i.--2231 UK pounds to 1342 UK pounds)). Sensitivity analysis showed that costs remained similar for 20 and 150 operations per annum. Exclusion of a dedicated cell salvage operator reduced autologous transfusion costs but did not have a significant impact on overall cost. CONCLUSION: Autologous transfusion is cost neutral in aortic surgery even when surgical activity is low.

Intraoperative autotransfusion in hip arthroplasty.

Two groups of patients having primary or revision total hip replacement were studied during a period of 11 months. The first group of 40 consecutive patients consented to have whole blood collected coincident with acute normovolemic hemodilution. An inventory of autologous red blood cells, plasma, and platelets was prepared in the operating room as a preliminary to surgery. Subsequently, the same supplies and equipment were used for autotransfusion intraoperatively. In a case-control study, another 40 patients having total hip replacements were matched for age, gender, and weight. The second group of patients refused hemodilution and received autotransfusion alone. The perioperative transfusion requirements of the two groups were compared. The total blood product donor exposure rate of the first group was 1/4 of the controls (0.6 and 2.4 donor units per patient, respectively). The average length of stay in the hospital after surgery for the first group was shortened significantly (6.2 versus 8.4 days), possibly from less immunogenic insult associated with increased transfusions of autologous blood products. Hemodilution, followed by autotransfusion, was cost effective in primary and revision total hip replacements, autotransfusion alone was cost effective only in revision arthroplasty.

A randomized trial comparing acute normovolemic hemodilution and preoperative autologous blood donation in total hip arthroplasty.

BACKGROUND: The value of acute normovolemic hemodilution (ANH) as compared to preoperative autologous blood donation (PABD) in orthopedic surgery is unknown. Therefore, a prospective, randomized study was conducted to compare these techniques in patients undergoing primary total hip arthroplasty. STUDY DESIGN AND METHODS: ANH patients underwent phlebotomy for up to 3 units, or to a target Hct level of 28 percent after induction of anesthesia. PABD patients were asked to donate up to 3 units before admission. RESULTS: Mean baseline Hct levels were not different in ANH and PABD patients (39. 7 +/- 4.5 vs. 41.8 +/- 3.8%, p = 0.09). No difference was found in allogeneic blood exposure among ANH and PABD cohorts: 4 (17%) of 23 ANH patients received a total of 9 allogeneic blood units, compared to no allogeneic transfusions in the PABD cohort (p = 0.30). Total blood costs associated with ANH were significantly (p<0.05) lower than blood costs associated with PABD ($151 +/- 154 vs. $680 +/- 253, respectively). CONCLUSION: In patients undergoing total hip arthroplasty, ANH is safe, can be considered equivalent to PABD in effectively reducing exposure to allogeneic RBCs, and is less costly than PABD.

Acute normovolemic hemodilution.

Acute normovolemic hemodilution was described to be useful as a blood conservation strategy more than 25 years ago, yet seldom is practiced today. The benefit of acute normovolemic hemodilution is perceived to be modest and the technique is not taught in anesthesia or surgery training programs. Acute normovolemic hemodilution is an autologous blood procurement strategy that is superior to the predeposit of autologous blood for several reasons: Acute normovolemic hemodilution is less costly, with an average cost of $25 per unit compared with $175 per unit predonated; and acute normovolemic hemodilution units are reinfused to patients before the patient leaves the operating room, so that the units need not be tested and there is no possibility of administrative error. Emerging clinical studies now show that acute normovolemic hemodilution is equivalent to predonated autologous blood in reducing allogeneic blood exposure in patients undergoing elective surgery.

Hemodilution with other blood reinfusion techniques in total hip arthroplasty.

Acute normovolemic hemodilution has been reported to result in blood savings varying from 18% to 90%. Very few of these are randomized prospective studies. This study attempts to determine the blood transfusion savings if acute normovolemic hemodilution is used in combination with autologous predonated blood and cell saver. Thirty-three patients undergoing total hip arthroplasty were assigned randomly to one of two groups (control, n = 16; hemodilution, n = 17). Patients in both groups entered an autologous predonation program if cleared medically and were placed on Cell Saver intraoperatively and in the postanesthesia care unit. In addition, the hemodilution group underwent acute normovolemic hemodilution preoperatively. Only 41% of the patients in the hemodilution group required any autologous blood transfusion as compared with 75% of the control group. In addition, the hemodilution group required a mean lower quantity of autologous blood transfusion (41% of the estimated blood loss) as compared with the control group (71%). The net anesthesia time increased by an average of 11.4 minutes in the hemodilution group. Acute normovolemic hemodilution is a safe procedure even in an older patient population. Hemodilution resulted in fewer patients needing autologous predonated blood transfusions. The major benefit of hemodilution was seen when predonation was not possible.

Intraoperative hemodilution is more cost-effective than preoperative autologous donation for patients undergoing procedures associated with a low risk for transfusion.

STUDY OBJECTIVE: To determine the utilization and cost of autologous blood that was donated preoperatively, and to compare it to the cost of employing intraoperative hemodilution to provide autologous blood for patients undergoing surgical procedures with a low risk for the need for transfusion. DESIGN: Retrospective chart review. SETTING: University medical center. PATIENTS: All ASA physical status I and II patients who underwent nononcologic gynecologic procedures and preoperatively donated autologous blood between July 1993 and June 1994. MEASUREMENTS AND MAIN RESULTS: The utilization and overall cost of predonated autologous blood was determined. The cost for employing intraoperative hemodilution and potential cost saving was then calculated. Of the 234 units of preoperatively donated autologous blood, 38 units were returned to patients who had an estimated blood loss of at least 500 ml, 32 units returned to patients who had an estimated blood loss less than 500 ml, and 164 units were wasted. No patient received allogeneic blood. The estimated total cost for all preoperatively donated autologous blood was $23,274.62. Employing hemodilution for those same patients would have cost $5,574.74, and resulted in a potential 75.6% savings. CONCLUSIONS: Inappropriate selection of patients for preoperative blood donation is costly. For those patients scheduled to undergo surgical procedures associated with a low probability for the need for blood transfusion, but who desire that autologous blood be available, hemodilution provides fresh whole blood, free from the possibility of processing or clerical errors, while decreasing blood bank utilization and affording substantial cost savings.