Acute Normovolemic Hemodilution Can Replace Preoperative Autologous Blood Donation as a Standard of Care for Autologous Blood Procurement in Radical Prostatectomy

Myocardial oxygen balance during acute normovolemic hemodilution: A novel compartmental modeling approach

BACKGROUND

Hemodilution was introduced initially as a blood conservation technique to reduce allogeneic blood transfusion in patients undergoing surgical procedures. Although the technique has been approved by the National Institute of Health consensus panel, limits of hemodilution under anesthetic conditions have not been established as they have in animal models.

METHODS

A novel multi-compartmental modeling approach has been proposed that includes the effect of anesthesia to quantify the effect of hemodilution on myocardial oxygen balance during myocardial ischemia.

RESULTS

The results showed that isovolemic hemodilution would cause detrimental effects around a hematocrit of 15%. Even though the fall in oxygen content caused by the decrease in hemoglobin concentration was compensated by an increase in coronary blood flow induced by hypoxic vasodilation and decreased viscosity, the endocardial tissue received less oxygen compared to the epicardial regions, and this sub-endocardial ischemia eventually led to cardiac failure. Statistical analysis also showed that the type of acellular replacement fluid failed to affect the heart rate, the stroke index or the cardiac index during hemodilution, and supplemental oxygen improved the endocardial oxygen supply.

CONCLUSION

The model validates the clinical conclusions that sub-endocardial ischemia causes cardiac failure under extreme hemodilution conditions and the model can also be easily integrated into other human simulators.

Zika Virus and Patient Blood Management

Sporadic Zika virus infections had only occurred in Africa and Asia until an outbreak in Micronesia (Oceania) in 2007. In 2013 to 2014, several outer Pacific Islands reported local outbreaks. Soon thereafter, the virus was likely introduced in Brazil from competing athletes from French Polynesia and other countries that participated in a competition there. Transmission is thought to have occurred through mosquito bites and spread to the immunologically naive population. Being also a flavivirus, the Zika virus is transmitted by the Aedes mosquito that is endemic in South and Central America that is also the vector of West Nile virus, dengue, and chikungunya. In less than a year, physicians in Brazil reported a many-fold increase in the number of babies born with microcephaly. Despite initial skepticism regarding the causal association of the Zika virus epidemic and birth defects, extensive basic and clinical research evidence has now confirmed this relationship. In the United States, more than 4000 travel-associated infections have been reported by the middle of 2016 to the Centers for Disease Control and Prevention. Furthermore, many local mosquito-borne infections have occurred in Puerto Rico and Florida. Considering that the virus causes a viremia in which 80% of infected individuals have no symptoms, the potential for transfusion transmission from an asymptomatic blood donor is high if utilizing donor screening alone without testing. Platelet units have been shown to infect 2 patients via transfusion in Brazil. Although there was an investigational nucleic acid test available for testing donors, not all blood centers were initially required to participate. Subsequently, the US Food and Drug Administration issued a guidance in August 2016 that recommended universal nucleic acid testing for the Zika virus on blood donors.In this report, we review the potentially devastating effects of Zika virus infection during pregnancy and its implication in cases of Guillain-Barre syndrome in adults. Furthermore, we urge hospital-based clinicians and transfusion medicine specialists to implement perisurgical patient blood management strategies to avoid blood component transfusions with their potential risks of emerging pathogens, illustrated here by the Zika virus. Ultimately, this current global threat, as described by the World Health Organization, will inevitably be followed by future outbreaks of other bloodborne pathogens; the principles and practices of perioperative patient blood management will reduce the risks from not only known, but also unknown risks of blood transfusion for our patients.

A novel approach to modeling acute normovolemic hemodilution

Acute normovolemic hemodilution (ANH) was introduced as a blood conservation technique to reduce patient exposure to allogenic blood transfusion during surgery. Despite years of research and experience, the best practice procedure, efficacy and safety of ANH remain in question. In this work, a numerical model is developed for the ANH procedure based upon a multi-compartmental, fluid model of the body. The model also analyzes the most commonly used acellular fluids for ANH or for fluid therapy following hemorrhage. The model allows user input of critical ANH parameters, providing the ability to simulate the patient׳s response in real time to many clinical scenarios, using various types of resuscitation fluids. First, the patient׳s response to a representative, clinical ANH protocol and surgery was simulated. Then, the effect of several variables was investigated including: type/amount of resuscitation fluid, number of blood units collected during ANH, and amount of surgical blood loss. Our simulations highlighted the importance of osmotic molecules within the blood in preventing excessive fluid retention and initiating fluid clearance after surgery. The developed model can be utilized as a tool to simulate and optimize a variety of proposed protocol related to the ANH procedure and surgery. It can also be utilized as an educational or training tool to become familiar with the ANH procedure.

Blood conservation strategies in orthopedic surgeries: A review

In orthopedics management of surgical blood loss is an important aspect which has evolved along with modern surgeries. Replacement of lost blood by transfusion alone is not the answer as was considered earlier. Complications like infection and immune reaction due to blood transfusion are a major concern. Today numerous techniques are available in place of allogenic blood transfusion which can be employed safely and effectively. In this article we have reviewed these techniques, their merits and demerits.

Acute normovolemic hemodilution can aggravate neurological injury after spinal cord ischemia in rats

BACKGROUND

Acute normovolemic hemodilution (ANH) is currently performed during thoracoabdominal aortic surgery. However, the effects of ANH on spinal cord ischemic injury are currently unknown. Because hemodilution below a certain level of hematocrit (Hct) aggravates the neurological damage after cerebral ischemia, we hypothesized that ANH may increase neurological damage after spinal cord ischemia. The aim of these experiments was to determine the effects of ANH on spinal cord ischemic injury.

METHODS

Thirty male Sprague-Dawley rats were randomly assigned to 1 of the following 3 groups: no hemodilution (group C), target Hct level of 30% (group HD30), and target Hct level of 25% (group HD25). ANH was performed upon withdrawal of blood and simultaneous replacement with the same volume with hydroxyethyl starch. Spinal cord ischemia and reperfusion were induced by using a balloon-tipped catheter placed in the descending thoracic aorta, and changes in mean arterial blood pressure were recorded. Neurological function of the hindlimbs was evaluated for 7 days and recorded using a motor deficit score (MDS) (0 = normal; 5 = complete paraplegia). The number of motor neurons within the spinal cord was counted after final MDS evaluation.

RESULTS

Group HD25 developed hypotension during the latter part of the ANH procedure. Group C and group HD30 experienced 3 minutes of reperfusion hypotension, whereas 6 minutes of hypotension was observed in group HD25. Two rats in group HD25 died during the experimental period. Seven days after reperfusion, the MDS of group C, group HD30, and group HD25 was 1.0 (0.5-2.0), 1.0 (0.5-2.0), and 4.0 (2.8-4.2) (median [95% confidence interval]), respectively. Group HD25 showed significantly higher MDS compared with group C (corrected P = 0.0018; 95% CI for median difference = 1.0-3.5). Motor neuron numbers in the anterior horns of group C, group HD30, and group HD25 were 26.5 (25.0-27.5), 23.5 (22.0-26.5), and 12.5 (8.4-16.6) (median [95% CI]), respectively. Motor neuron numbers of group HD25 were significantly lower than those of group C (corrected P < 0.0001; 95% CI for median difference = 9.0-18.0).

CONCLUSION

The results of the present study indicate that intraoperative ANH to an Hct of 25%, combined with coincident hypotension, caused a delayed recovery of baseline mean arterial blood pressure during the reperfusion period and aggravated neurological outcome after spinal cord ischemia.

Intraoperative red blood cell salvage and autologous transfusion during open radical retropubic prostatectomy: a cost-benefit analysis

INTRODUCTION

Open radical retropubic prostatectomy (RRP) has an average blood loss of over 1,000 ml. This has been reported even from high volume centres of excellence. We have looked at the clinical and financial benefits of using intraoperative cell salvage (ICS) as a method of reducing the autologous blood transfusion requirements for our RRP patients.

MATERIALS AND METHODS

Group A comprised 25 consecutive patients who underwent RRP immediately prior to the acquisition of a cell saver machine. Group B consisted of the next 25 consecutive patients undergoing surgery using the Dideco Electa (Sorin Group, Italy) cell saver machine. Blood transfusion costs for both groups were calculated and compared.

RESULTS

The mean postoperative haemoglobin was similar in both groups (11.1 gm/dl in Group A and 11.4 gm/dl in Group B). All Group B patients received autologous blood (average 506 ml, range: 103-1,023 ml). In addition, 5 patients (20%) in Group B received a group total of 16 units (average 0.6 units) of homologous blood. For Group A the total cost of transfusing the 69 units of homologous blood was estimated as £9,315, based on a per blood unit cost of £135. This cost did not include consumables or nursing costs.

CONCLUSIONS

We found no evidence that autologous transfusions increased the risk of early biochemical relapse or of disease dissemination. ICS reduced our dependence on donated homologous blood.

[Strategies for transfusion-free radical retropubic prostatectomy in Jehovah's witnesses]

OBJECTIVES

While radical retropubic prostatectomy carries significant potential for blood loss requiring transfusion, Jehovah's Witnesses do not permit the use of allogeneic blood products. This study presents strategies for transfusion-free radical retropubic prostatectomy for prostate cancer treatment in Jehovah's Witnesses patients.

METHODS

From March 1998 to May 2009, 25 Jehovah's Witnesses patients diagnosed with prostate cancer underwent radical prostatectomy and bilateral iliac and obturatory lymphadenectomy. Preoperative hemoglobin boost utilizing erythropoietin aiming hemoglobin over 14 g/dL, normovolemic hemodilution and availability of cell salvage machine were provided for blood loss management.

RESULTS

The mean age was 62 (43 to 70) years and the mean hospitalization time was 3.5 (3 to 7) days. Mean intra-operative bleeding was 430 (+/-120) ml and the mean pre- and post-operative hemoglobin (measured before discharge) was 15.1 (+/-0.8) and 11.7 (+/-2.3) g/dL, respectively. There was no need for cell salvage machine or transfusion. The lowest hemoglobin was 5.7 g/dL due to post-operative bladder neck bleeding, which responded to twenty days of office based erythropoietin subcutaneously on alternate days reaching 12 g/dL hemoglobin. There was no complication related to non-transfusion.

CONCLUSIONS

The proposed techniques were essential for maximum reduction of the need for transfusions without increasing complications. Further studies are needed to introduce these methods in all cases of radical retropubic prostatectomy regarding the benefits in lowering costs and risks related to transfusion.

Acute normovolemic hemodilution for radical retropubic prostatectomy and radical cystectomy

OBJECTIVES

Radical retropubic prostatectomy (RRP) and radical cystectomy (RCx) are well tolerated and widely performed. Because intraoperative blood loss is one of the most common problems, we performed acute normovolemic hemodilution (ANH) to prevent allogenic blood transfusion (ABT). In this study we tried to clarify the safety, effectiveness and problems of ANH at urologic operations.

METHODS

The study included 169 patients who underwent RRP and 97 patients underwent RCx from April 2003 to March 2006. The eligible patients for ANH were required to have preoperative hemoglobin of 12 g/dL or more without history of myocardial ischemia. The amount of blood collected was 800 mL in RRP and 800 mL or 1200 mL in RCx. Neoadjuvant chemotherapy was performed in 11 (11.3%) of 97 patients with RCx.

RESULTS

ANH was available in 164 (97.0%) of 169 patients in RRP and 41 (42.3%) of 97 patients in RCx. All 11 (11.3%) patients who received neoadjuvant chemotherapy before RCx revealed anemia and all were excluded from ANH. No patients had an hypovolemic event develop during the autologous blood being stored. The median volume of intraoperative blood loss was 1400 mL in 164 RRP and 19 patients (11.6%) required ABT. In 41 patients undergoing RCx, the median volume of blood loss was 1720 mL and 13 patients (32.5%) required ABT. In the postoperative period, no patients had cardiovascular or pulmonary complications develop originated from ANH.

CONCLUSIONS

ANH is a safe and useful method of transfusion during RRP and RCx. ANH can be recommended for patients who need these operations.

Low hematocrit impairs gastric mucosal CO2 removal during experimental severe normovolemic hemodilution

OBJECTIVE

The net effects of acute normovolemic hemodilution with different hemoglobin levels on splanchnic perfusion have not been elucidated. The hypothesis that during moderate and severe normovolemic hemodilution, systemic and splanchnic hemodynamic parameters, oxygen-derived variables, and biochemical markers of anaerobic metabolism do not reflect the adequacy of gastric mucosa, was tested in this study.

METHODS

Twenty one anesthetized mongrel dogs (16 +/- 1 kg) were randomized to controls (CT, n = 7, no hemodilution), moderate hemodilution (hematocrit 2 5% +/- 3%, n = 7) or severe hemodilution (severe hemodilution, hematocrit 15% +/- 3%, n = 7), through an isovolemic exchange of whole blood and 6% hydroxyethyl starch, at a 20 mL/min rate, to the target hematocrit. The animals were followed for 120 min after hemodilution. Cardiac output (CO, L/min), portal vein blood flow (PVF, mL/min), portal vein-arterial and gastric mucosa-arterial CO2 gradients (PV-artCO2 and PCO2 gap, mm Hg, respectively) were measured throughout the experiment.

RESULTS

Exchange blood volumes were 33.9 +/- 3.3 and 61.5 +/- 5.8 mL/kg for moderate hemodilution and severe hemodilution, respectively. Arterial pressure and systemic and regional lactate levels remained stable in all groups. There were initial increases in cardiac output and portal vein blood flow in both moderate hemodilution and severe hemodilution; systemic and regional oxygen consumption remained stable largely due to increases in oxygen extraction rate. There was a significant increase in the PCO2-gap value only in severe hemodilution animals.

CONCLUSION

Global and regional hemodynamic stability were maintained after moderate and severe hemodilution. However, a very low hematocrit induced gastric mucosal acidosis, suggesting that gastric mucosal CO2 monitoring may be useful during major surgery or following trauma.

Intraoperative cell salvage during radical prostatectomy is not associated with greater biochemical recurrence rate

OBJECTIVES

To evaluate the risk of long-term biochemical recurrence for patients who receive cell-salvaged blood. Radical retropubic prostatectomy (RRP) is historically associated with the potential for significant blood loss. Different blood management strategies include blood donation, hemodilution, preoperative erythropoietin, and intraoperative cell salvage (IOCS). Oncologic surgeons have been reluctant to use IOCS because of the potential risk of tumor dissemination.

METHODS

We retrospectively analyzed an RRP database and compared those who did and did not receive cell-salvaged blood by baseline parameters, pathologic outcomes, and biochemical recurrence. We also stratified our patients according to the risk of recurrence.

RESULTS

A total of 1038 patients underwent RRP between 1992 and 2003. Of these, 265 (25.5%) received cell-salvaged blood and 773 (74.5%) did not. The two groups had similar baseline characteristics. No differences were found between the two groups when compared by risk of seminal vesicle invasion or positive surgical margins. Those who received cell-salvaged blood had a lower risk of extraprostatic extension. The median follow-up for all patients was 40.2 months. The overall risk of biochemical recurrence at 5 years for those who did and did not receive cell-salvaged blood was 15% and 18%, respectively (P = 0.76). No significant differences were found in the risk of biochemical recurrence when patients were stratified according to low, intermediate, and high risk.

CONCLUSIONS

IOCS is a safe and effective blood management strategy for patients undergoing RRP. The risk of biochemical recurrence was not increased for those who received cell-salvaged blood. Concerns about spreading tumor cells by way of IOCS would seem unwarranted.

Use of acute normovolemic hemodilution in patients undergoing radical prostatectomy

OBJECTIVES

To evaluate the efficacy and safety of acute normovolemic hemodilution (ANH) in patients undergoing radical prostatectomy. Preoperative autologous blood donation (PAD) is widely accepted as a means of reducing the need for allogeneic blood transfusion in radical prostatectomy. ANH is an alternative method for obtaining autologous blood.

METHODS

On the basis of our previous report that showed the equivalence of PAD and ANH, we prospectively replaced PAD with ANH as a standard practice for radical prostatectomy after September 1999. Of 174 radical prostatectomy patients between September 1999 and June 2004, 153 underwent ANH alone, 15 chose to receive both PAD and ANH, and ANH was contraindicated in 15 because of comorbidities.

RESULTS

For the 153 patients undergoing ANH alone, 1032 +/- 201 mL of autologous blood was collected. With an intraoperative blood loss of 1602 +/- 926 mL, 14 patients (9.2%) received allogeneic blood transfusion. The preoperative, intraoperative nadir, and postoperative hematocrit value was 43.6% +/- 3.4%, 25.8% +/- 3.8%, and 31.9% +/- 4.3%, respectively. No patient experienced a perioperative adverse event related to hemodilution or blood transfusion.

CONCLUSIONS

Our continued experience has shown that ANH is a safe and effective means of autologous blood procurement. Given its advantages, including lower cost, lower risk, and simplicity, we conclude that ANH can replace conventional PAD for use in radical prostatectomy, although the true value of ANH should be determined by future randomized studies including a no-treatment control group.

Acute Normovolemic Hemodilution

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

[Anaesthesia and prostate surgery]

OBJECTIVES

To review the current data about anaesthetic management in prostate surgery with special regards on analysis and prevention of specific risks, appropriate anaesthetic procedure keeping with surgery and patient, recognition and treatment of adverse events.

DATA SOURCES AND EXTRACTION

The Pubmed database was searched for articles (1990-2004) combined with references analysis of major articles on the field.

DATA SYNTHESIS

It is strongly recommended to settle germfree urine in the preoperative period. The thromboembolic risk of radical retropubic prostatectomy for cancer parallels lower abdomen oncologic surgery and is prolonged. Preoperative evaluation of cardiovascular, respiratory, neurological and metabolic comorbidity is a source of prognostic information and an essential tool in the management of elderly patients with prostate disease. Extreme patient positioning applied in prostate surgery induces haemodynamic and respiratory changes and are associated with severe muscular and nervous injuries. The laparoscopic access for radical prostatectomy is a growing alternative to the open surgical procedure. Acute normovolaemic haemodilution is a consistent and cost-effective blood conservation strategy in reducing allogenic blood transfusion for radical retropubic prostatectomy. Whether open transvesical or transurethral prostatectomy for treatment of benign hypertrophy depends on the size of the gland: transurethral resection is safe up to 80 g. Intrathecal anaesthesia with a T9 cephalad spread of sensory block, produces adequate conditions for transurethral prostatectomy and allows a rapid diagnosis of irrigating fluid absorption syndrome. In spite of recommended preoperative antibiotic prophylaxis, bacteriemias are frequent during transurethral prostate resection.

A Comparative Evaluation of Inhaled Halothane, Isoflurane, and Sevoflurane During Acute Normovolemic Hemodilution in Dogs

The hemodynamic response to acute normovolemic hemodilution (ANH) can be affected by the anesthetics used. We randomized 18 mongrel dogs to undergo ANH with 3 different inhaled anesthetics: halothane, isoflurane, or sevoflurane. Hemodynamics, oxygen transport, and gastric pH were measured before blood withdrawal, at the end of hemodilution, and 30 and 60 min after the end of hemodilution. The baseline measurements of all hemodynamic variables were similar among groups, with the exception of heart rate, which was more rapid in the sevoflurane group. Thirty minutes after hemodilution, the cardiac index increased 88%, 86%, and 157% in the halothane, isoflurane, and sevoflurane groups, respectively, whereas arterial-venous oxygen differences and oxygen consumption were larger in the halothane group compared with the isoflurane and sevoflurane groups. Gastric pH obtained by tonometry did not change and was not different among groups. Because the hemodynamic response to ANH was not blunted, all three anesthetics may be safely used for the maintenance of anesthesia.

Intraoperative cell salvage during radical prostatectomy: a safe technique for Jehovahs witnesses

Radical retropubic prostatectomy (RRP) is an operation historically associated with the potential for significant blood loss. Patients who refuse a blood transfusion, such as Jehovah's witnesses, may be only offered radiation therapy as potentially curative treatment for prostate cancer because of the potential for a transfusion. Intraoperative cell salvage (IOCS) is an effective blood management strategy for patients who are not willing to accept predonated autologous or allergenic blood. We present our management for Jehovah's Witness patients with clinically localized prostate cancer, emphasizing our blood management approach. This is the first such report.

Transfusion in surgery and trauma

The role of transfusion in surgery and trauma continues to evolve with our greater understanding of the true indications for and effects of transfusion. The potential adverse immune consequences and end-organ effects of blood transfusion must be weighed against the need for replacement of blood volume and oxygen-carrying capacity. The techniques to conserve blood and avoid transfusion play an important role in caring for the bleeding surgical patient. The future holds great promise for the possibility of redefining the art of blood transfusion and perhaps one day replacing it entirely.

Preoperative autologous donation versus cell salvage in the avoidance of allogeneic transfusion in patients undergoing radical retropubic prostatectomy

There are many methods for preventing allogeneic blood administration during radical retropubic prostatectomy, and many of these methods have been compared with each other, but no studies have compared preoperative autologous donation (PAD) and cell salvage (CS). In this study, we evaluated these two methods in patients undergoing radical retropubic prostatectomy. In a prospective cohort model, allogeneic exposure in patients from one surgeon who routinely had his patients donate blood before surgery was compared with that in patients from a different surgeon who predominantly used CS. Fifty patients were enrolled in the study: 26 in the PAD group and 24 in the CS group. No difference in allogeneic exposure was seen between the two groups. A significant difference was seen in the volume of red blood cells lost (891 +/- 298 mL versus 1134 +/- 358 mL in the PAD and CS groups, respectively). We conclude that PAD and CS are equivalent in their ability to avoid allogeneic transfusion. Larger surgical blood loss in the CS group would suggest that in a more rigorously designed study, CS might provide better allogeneic avoidance than PAD.

IMPLICATIONS

In this prospective cohort study, cell salvage and preoperative autologous donation were compared with respect to their ability to avoid allogeneic transfusion. There was a suggestion that cell salvage might offer better allogeneic transfusion avoidance.

Influence of crystalloid and colloid replacement solutions on hemodynamic variables during acute normovolemic hemodilution

STUDY OBJECTIVE

To determine whether, in maintaining normovolemia during acute normovolemic hemodilution, replacement fluid choice influences intraoperative hemodynamic variables.

DESIGN

Prospective, randomized, single-blinded study.

SETTING

Operating room of a tertiary-care university hospital.

PATIENTS

40 adult, ASA physical status I, II, and III patients scheduled for acute normovolemic hemodilution during radical prostatectomy.

INTERVENTIONS

Patients were randomly assigned to four replacement fluid groups to receive 1) Ringer's lactate, 2) 5% albumin, 3) 6% dextran 70, or 4) 6% hetastarch. A standardized general anesthetic was used, and patients underwent moderate hemodilution to a target hemoglobin of 9 gm/dL.

MEASUREMENTS

Hemodynamic variables were recorded using standard monitors, 5-lead electrocardiography, radial arterial catheter, and pulmonary artery catheter. Red blood cell loss for the entire hospitalization was calculated.

MAIN RESULTS

Demographic and clinical outcome data were similar among the groups. During acute normovolemic hemodilution, heart rate and pulmonary capillary wedge pressure were unchanged from baseline in all groups, but patients receiving Ringer's lactate or albumin had greater declines in mean arterial pressure at the end of acute normovolemic hemodilution. Cardiac and oxygen consumption indexes were stable during acute normovolemic hemodilution, but oxygen extraction increased.

CONCLUSIONS

During hemodilution, anesthetized patients maintain whole body oxygenation by increasing oxygen extraction. The administration of hetastarch or dextran as the replacement fluid during acute normovolemic hemodilution is associated with a more stable mean arterial pressure, but overall acute normovolemic hemodilution is well tolerated irrespective of the replacement fluid used.

Haemodilutional Effect of Standard Fluid Management Limits the Effectiveness of Acute Normovolaemic Haemodilution in AAA Surgery—Results of a Pilot Trial

OBJECTIVE

To evaluate the impact of standard fluid management on the effectiveness of ANH as a blood conservation method in elective open AAA repair.

DESIGN

Prospective randomised controlled study.

METHODS

Thirty-four patients undergoing elective AAA repair were randomised to have ANH (16) or act as controls (18). Intra-operative cell salvage was permitted in both groups. Haemoglobin (Hb) concentrations were determined at variable intervals peri-operatively. Blood loss and the use of heterologous blood were recorded.

RESULTS

The pre- and post-operative Hb concentrations, surgical blood loss and the use of cell salvage were similar in both groups. Hb concentration (median, range) decreased significantly from pre-operative to aortic clamping (with blood loss <100 ml) in ANH patients from 8.8 (7.5-10.2) to 5.7 (4.2-6.6)mmol/l following ANH but also in controls from 8.6 (7.5-9.7) to 7.0 (4.5-9.0)mmol/l due to fluid infusion (P<0.01 for every comparison). Bank blood requirements were similar: median 2 units in ANH and 2.5 units in control patients (P=0.68).

CONCLUSIONS

Large volumes of fluids infused during AAA repair already conserve blood by the mechanism of hypervolaemic haemodilution. When cell salvage is used with standard fluid management during AAA repair, additional ANH is ineffective in saving blood.

Planning for hemorrhage. Steps an anesthesiologist can take to limit and treat hemorrhage in the obstetric patient

Obstetric hemorrhage continues to be a significant cause of maternal mortality and morbidity. Blood transfusion in such circumstances may be life saving but involves exposing the patient to additional risks. Limiting blood transfusion and using autologous blood when possible may reduce some of these risks. This article outlines the techniques that may be used to limit and more effectively treat hemorrhage in the obstetric patient, with particular attention paid to reducing the use of allogeneic blood transfusion.

Hyperoxic ventilation at the critical haematocrit

OBJECTIVE

During normovolaemic haemodilution arterial O(2)-content decreases exponentially. Nevertheless, tissue oxygenation is first maintained initially by increased organ perfusion and O(2)-extraction. As soon as these compensatory mechanisms are exhausted, myocardial ischaemia and tissue hypoxia occur at an individual 'critical' haematocrit (Hct) value. This study was conducted in order to assess whether tissue hypoxia at the critical Hct is reversed by hyperoxic ventilation with 100% O(2).

METHOD

Eighteen anaesthetized pigs were ventilated with room air and were hemodiluted by 1:1 exchange of blood with 6% pentastarch to their individual critical Hct (onset of myocardial ischaemia; significant ECG changes). At the critical Hct, hyperoxic ventilation was initiated. In nine complete datasets, global O(2) delivery and consumption, local tissue O(2) partial pressure (tpO(2)) (MDO-Electrode, Eschweiler, Kiel, Germany) and organ blood flow (microsphere method) in skeletal muscle were analyzed at baseline, after haemodilution to the critical Hct and after 15 min of hyperoxic ventilation.

RESULTS

At the critical Hct (7.2+/-1.2%), tpO(2) was reduced from 23+/-3 to 10+/-2 Torr with 50% of all values in the hypoxic range (<10 Torr, all P<0.05). During hyperoxic ventilation, contribution of physically dissolved O(2) to the O(2) delivery and O(2) consumption increased by 400 and 563% (P<0.05) and instantly restored tpO(2) to 18+/-2 Torr, (hypoxic values 25%, P<0.05).

CONCLUSION

Hyperoxic ventilation reversed tissue hypoxia at the critical Hct due to preferential utilization of plasma O(2) and allowed temporary preservation of tissue oxygenation. During haemodilution, hyperoxic ventilation might offer an effective bridge until red cells are ready for transfusion.

The influence of crystalloid and colloid replacement solutions in acute normovolemic hemodilution: a preliminary survey of hemostatic markers

Acute normovolemic hemodilution (ANH), in which blood for autologous use is collected immediately before the onset of surgical blood loss, is a recommended autologous blood procurement technique for blood conservation. Both crystalloid and colloid replacement fluids have been used to maintain normovolemia during ANH, but few data are available to justify the use of a particular replacement fluid. Therefore, we designed a prospective, randomized study to determine if the replacement fluid choice affects various coagulation variables and perioperative blood loss. Forty adult patients, ASA physical status 1-3, scheduled for ANH during radical prostatectomy were randomly assigned to one of four replacement fluid groups: (a) Ringer's lactate, (b) 5% albumin, (c) 6% dextran 70 (DEX), or (d) 6% hetastarch (HES). After the induction of a standardized general anesthetic, all patients underwent ANH to a final hemoglobin level of 9 g/dL. Complete blood count, prothrombin time, partial thromboplastin time, fibrinogen, factors V and VIII levels, bleeding time, and thromboelastography (TEG measurements were obtained at similar time points in the procedure. When compared with baseline, activated partial thromboplastin time decreased and factor VIII levels increased in the postanesthesia care unit in both the Ringer's lactate and 5% albumin groups. The DEX and HES groups demonstrated a decrease in TEG maximum amplitude between preoperative and postanesthesia care unit measurements and TEG alpha (angle) was decreased from baseline in the DEX group. The changes in factor VIII, activated partial thromboplastin time, and TEG measurements indicate that HES and DEX may attenuate the hypercoagulability related to surgery.

Clinical trial of esmolol-induced controlled hypotension with or without acute normovolemic hemodilution in spinal surgery

BACKGROUND

Drug-induced controlled hypotension (CH) combined with acute normovolemic hemodilution (ANH) is being widely used for blood conservation in surgical patients. The purpose of this study was to investigate the efficacy and safety of esmolol-induced CH combined with ANH (hematocrit down to 28%).

METHODS

Thirty patients who were scheduled to receive spinal surgery were randomly divided into two groups: an esmolol-induced CH alone group (esmolol group, n=15) and a CH-ANH combined group (E-ANH group, n=15). Controlled hypotension was induced with esmolol 500 micro g/kg, followed by a continuous infusion of 0-300 micro g/kg/min to maintain mean arterial pressure at 55-65 mmHg.

RESULTS

The mean infusion rate of esmolol in the esmolol-ANH group was 46+/-6 micro g/kg/min (mean+/-SD), which was significantly lower than the 77+/-9 micro g/kg/min used in the esmolol group (P<0.05). The number of units of homologous blood (packed RBC) transfused perioperatively was 2.2+/-0.6 units in the esmolol-ANH group, which was significantly less than 4.3+/-0.4 units used in the esmolol group (P<0.01). While O2 delivery decreased significantly during CH, O2 consumption remained unchanged in both groups. No complications resulted from CH or ANH in any of the groups.

CONCLUSION

Our data suggest that ANH of moderate degree can be combined with esmolol-induced CH to improve blood conservation in surgical patients.

Identifying patients for blood conservation strategies

BACKGROUND

Generally, only the type of operation is used to estimate the need for perioperative homologous blood transfusion. This study quantified the extent to which the estimation could be improved if, in addition, simple patient characteristics were taken into account.

METHODS

Retrospective data on 24 509 consecutive adult surgical patients were used to derive and validate three models to predict perioperative homologous transfusion. The first model was a univariable model with type of operation as the only predictor. The second and third models were a full and a simplified multivariable logistic regression model. The performance of the multivariable models was tested in two validation sets: in similar patients who had operations in the same general hospital (internal validation) and in patients who had operations in a university hospital (external validation). The areas under the receiver-operator characteristic (ROC) curve were compared with that found in the derivation set.

RESULTS

There were no important differences in characteristics between the derivation and validation sets. The ROC area of the model including surgery only was 0.92 (99 per cent confidence interval (c.i.) 0.91 to 0.94) and that of the full and simplified multivariable models 0.95 (99 per cent c.i. 0.94 to 0.96) and 0.94 (99 per cent c.i. 0.93 to 0.95) respectively. The latter two were significantly different from the first one. In the external validation set the ROC area of the simplified model was 0.84 (95 per cent c.i. 0.83 to 0.86). Patients who had a preoperative haemoglobin level lower than 13 g/dl and underwent major invasive surgery had the highest risk (43 per cent) of transfusion.

CONCLUSION

A simple algorithm using type of operation and haemoglobin concentration was effective in identifying patients likely to need perioperative homologous blood transfusion.

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.

Efficacy of preoperative donation of autologous blood in patients undergoing radical retropubic prostatectomy

BACKGROUND

Radical retropubic prostatectomy (RRP) has resulted in substantial blood loss and the frequent need for homologous blood transfusion. In this study, the efficacy of autologous blood transfusion, from medical and financial perspectives, was evaluated in patients undergoing RRP.

METHODS

Between 1994 and 2000, 80 patients with localized prostate cancer underwent RRP in our institute. Based on informed consent, preoperative donation of autologous blood (PDA) was performed in 65 out of 80 patienets. Four or six units were donated during the first 3 years; however, donation units were reduced to a maximum of 4 units since 1997 onwards. The discard rate of donated blood and frequency of homologous transfusion were examined. Changes of hematocrit (Ht) and hemoglobin (Hb) levels through donation and surgery and important factors that may affect postoperative levels of Ht and Hb were evaluated in 56 patients receiving 4-unit donations.

RESULTS

Overall, 2 or 4 units of donated blood were discarded in four patients and homologous transfusion was required in two patients. In 56 patients receiving 4-unit donation, the mean Ht level at predonation was 43.3%. Following donation, this decreased to 35.7%. The administration of recombinant human erythropoietin (rHuEpo) relieved declining Ht levels following donation, but changes in Ht levels after surgery were minor. Important factors related to postoperative decline of Ht and Hb levels were operative time and blood loss.

CONCLUSIONS

The program of 4-unit PDA can be performed safely without rHuEpo injection, and it is useful to reduce the risk of requiring homologous transfusion. However, more efficient programs to relieve patient burden and to reduce medical cost are needed.

Intraoperative cell salvage in radical retropubic prostatectomy

OBJECTIVES

To investigate the efficacy and safety of intraoperative cell salvage with autotransfusion using leukocyte reduction filters in patients undergoing radical retropubic prostatectomy (RRP).

METHODS

Between September 1996 and March 1999, 62 patients (age range 48 to 70 years) with clinically localized prostate cancer underwent RRP with intraoperative cell salvage as the sole blood management technique. Salvaged blood was passed through a leukocyte reduction filter before autotransfusion. The 62 cell salvage patients were compared with a cohort who predonated 1 to 3 U autologous blood (n = 101). The estimated blood loss, preoperative and postoperative hematocrit, need for homologous transfusion, and biochemical recurrence rates were compared between the two groups. The progression-free survival rates were compared using the Kaplan-Meier method.

RESULTS

No difference was found in preoperative prostate-specific antigen level, pathologic stage, or estimated blood loss between the cell salvage and autologous predonation groups. The preoperative and postoperative hematocrit levels were higher in the cell salvage group (42.7% versus 39.6% and 31.3% versus 27.9%, respectively; P <0.001 for each). The homologous transfusion rates were lower in the cell salvage group (3% versus 14%, P = 0.04). The incidence of progression-free survival (prostate-specific antigen level 0.4 ng/mL or greater) was no different between the groups (P = 0.41).

CONCLUSIONS

Intraoperative cell salvage with autotransfusion using leukocyte reduction filters in RRP results in higher perioperative hematocrit levels and low homologous transfusion rates and eliminates the need for autologous predonation. Cell salvage does not appear to be associated with an increased risk of early biochemical progression after RRP.

The effect of acute normovolaemic haemodilution on blood transfusion requirements in abdominal aortic aneurysm repair

OBJECTIVE

to evaluate the impact of acute normovolaemic haemodilution (ANH) on the blood transfusion requirements in elective abdominal aortic aneurysm (AAA) repair in a single vascular unit.

METHODS

thirty-two patients underwent ANH during elective AAA repair between 1992 and 1997. The operation was performed by the same surgeon/anaesthetist team in 75% of cases. Their demographic details, type of aneurysm (infra-renal or supra-renal), preoperative blood cross match, use of intra-operative red cell salvage, blood loss, peri-operative bank blood requirements, pre-op and on-discharge haemoglobin levels and post-operative outcome were recorded. The results were compared to a group of 40 randomly selected patients (to represent the unit average) who underwent elective AAA repair by variable surgeon/anaesthetist teams without ANH in the same time period.

RESULTS

there were more supra-renal AAA repairs in the ANH group (8/32) than in the non-ANH group (0/40, p<0.01). ANH patients required significantly less blood transfusion peri-operatively (median 2 units) than the non-ANH patients (median 3 units, p=0.02). There were no other significant differences between the variables measured.

CONCLUSION

these results suggest that a dedicated team can achieve significant reductions in the use of heterologous blood transfusion compared to the vascular unit average experience by the effective use of ANH.

Diaspirin crosslinked hemoglobin enables extreme hemodilution beyond the critical hematocrit

BACKGROUND

Normovolemic hemodilution is an effective strategy to limit perioperative homologous blood transfusions. The reduction of hematocrit related to hemodilution results in reduced arterial oxygen content, which initially is compensated for by an increase in cardiac output and oxygen extraction ratio. To increase the efficacy of hemodilution, a low hematocrit should be aimed for; however, this implies the risk of myocardial ischemia and tissue hypoxia.

OBJECTIVE

To assess whether hemodilution can be extended to lower hematocrit values by the use of a hemoglobin-based artificial oxygen carrier solution.

DESIGN

Prospective, randomized, controlled.

SETTING

Animal laboratory of a university hospital.

SUBJECTS

Twelve anesthetized, mechanically ventilated pigs.

INTERVENTIONS

Isovolemic hemodilution was performed with either 10% diaspirin crosslinked hemoglobin (DCLHb Baxter Healthcare, Boulder, CO; n = 6) or 8% human albumin solution (HSA, oncotically matched to DCLHb, Baxter Healthcare; n = 6) to a hematocrit of 15%, 8%, 4%, 2%, and 1%.

MEASUREMENTS AND MAIN RESULTS

In both groups, measurements were performed at baseline at the previously mentioned preset hematocrit values and at the onset of myocardial ischemia characterized by critical hematocrit (significant ST-segment depression >0.1 mV and/or arrhythmia). To determine peripheral tissue oxygenation and myocardial perfusion and function, the following variables were evaluated: total body oxygen transport variables, tissue oxygen partial pressure (tPo2, MDO-Electrode, Eschweiler Kiel, Germany) on the surface of the skeletal muscle, coronary perfusion pressure, left ventricular (LV) end-diastolic pressure, global and regional myocardial contractility (maximal change in pressure over time, LV segmental shortening, microsonometry method), LV myocardial blood flow (fluorescent microsphere technique), LV oxygen delivery, and the ratio between LV subendocardial and subepicardial myocardial perfusion. In the HSA group, critical hematocrit was found at 6.1 (1.8)% (hemoglobin, 2 g x dL(-1)), whereas all DCLHb-treated animals survived hemodilution until hematocrit 1.2 (0.2)% (hemoglobin, 4.7 g x dL(-1)) was achieved without signs of hemodynamic instability. Although arterial oxygen content was higher in the DCLHb group at 1.2% hematocrit than in the HSA group at critical hematocrit (i.e., hematocrit, 6.1%; hemoglobin, 2 g.dL-1) neither oxygen delivery and oxygen uptake nor median tPo2 and hypoxic tPo2 values on the skeletal muscle were different between groups. In contrast, subendocardial ischemia was absent in DCLHb-diluted animals until 1.2% hematocrit was achieved. This was attributable to a higher coronary perfusion pressure (65 (22) mm Hg vs. 19 (8) mm Hg; p <.05), higher subendocardial perfusion (4.1 (2.6) mL.min-1.g-1 vs. 1.2 (0.4) mL x min(-1) x g(-1)), and subendocardial oxygen delivery (5.7 (2) mL x min(-1) x g(-1), p <.05) in DCLHb-diluted animals, resulting in superior myocardial contractility reflected by maximal change in pressure over time (3829 (1914) vs. 1678 (730); p <.05) and higher regional myocardial contractility (11 (8)% vs. 6 (2)%; p <.05). An increased LV end-diastolic pressure reflected LV myocardial pump failure in HSA-diluted animals but was unchanged in DCLHb-diluted animals. In the DCLHb group, systemic vascular resistance index remained at baseline values throughout the protocol, whereas coronary vascular resistance decreased. In contrast, both variables decreased in HSA-diluted animals.

CONCLUSION

DCLHb as a diluent allowed for hemodilution beyond the hematocrit value, determined "critical" after hemodilution with HSA (6.1% (1.8)%). Even at 1.2% hematocrit (hemoglobin, 4.7 g x dL(-1)) myocardial perfusion and function were maintained, although at the expense of peripheral tissue oxygenation. This discrepancy in regional oxygenation might be caused by a redistribution of blood flow favoring the heart, which is related to a disproportionate decrease of coronary vascular resistance index during hemodilution with DCLHb.

Anesthesia for radical prostatectomy, cystectomy, nephrectomy, pheochromocytoma, and laparoscopic procedures

This article presents some of the more salient aspects of the anesthetic management of the common major renal surgical procedures and discusses the physiology and anesthetic implications of minimally invasive laparoscopic urologic surgery.

Efficacy of preoperative autologous blood donation: analysis of blood loss and transfusion practice in total hip replacement

STUDY OBJECTIVE

To determine the frequency of allogeneic transfusion for total hip replacement (THR) surgery and to examine the efficacy of preoperative autologous blood donation (PABD) under specified, standardized blood transfusion guidelines.

DESIGN

Prospective, nonrandomized study.

SETTING

University medical center.

PATIENTS

All ASA physical status I, II, III, and IV patients undergoing single, primary, THR surgery from April 1998 to March 1999.

INTERVENTIONS

All patients received standardized transfusion and anticoagulation therapy. Demographic, blood loss, and transfusion data were collected and compared between all patients participating in PABD (donors) and patients not participating in PABD (nondonors). Overall allogeneic blood exposure was established. Since most anemic patients could not participate in PABD, allogeneic transfusion frequency was also examined in a subset of nonanemic patients (hemoglobin > or =12 g/dL) who were potentially able to participate in PABD.

MEASUREMENTS AND MAIN RESULTS

n = 231 patients, 142 donors and 89 nondonors. Mean estimated blood volume (EBV) of donors was 4991 +/- 1042 mL versus nondonors 4631 +/- 1108 mL (p < 0. 01). ASA physical status I-II/III-IV among donors was 118/24 versus nondonors 61/28 (p < 0.01). Overall allogeneic blood exposure was 22% (51/231). Allogeneic transfusion frequency for all donors was 15% (22/142) versus nondonors 33% (29/89) (p < 0.05). Among nonanemic patients, donor versus nondonor EBV and ASA physical status I-II/III-IV were 5074 +/- 1019 mL versus 4743 +/- 1172 mL and 107/20 versus 48/15 (p = NS); allogeneic transfusion frequency reduced to 13% (16/127) versus 17% (11/63) (p = NS), respectively.

CONCLUSIONS

Allogeneic blood exposure was >10% despite the use of PABD. The efficacy of PABD has been obscured by the fact that donors of autologous blood tend to be larger and healthier than nondonors. After exclusion of anemic patients, autologous donors and nondonors were clinically comparable and the difference in allogeneic blood exposure was not statistically significant. PABD offers only a modest, if any, benefit for THR surgery.

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.

Preoperative treatment with recombinant human erythropoietin or predeposit of autologous blood in women undergoing primary hip replacement

BACKGROUND

Controversy exists about the advantages of predeposit of autologous blood (PDAB), and whether more comfortable blood conservation regimens may yield comparable results. To test the hypothesis that preoperative treatment with recombinant human erythropoietin (rHuEPO) with or without acute concomitant normovolaemic haemodilution (ANHD) is as effective as PDAB in reducing allogeneic blood transfusions, we conducted a prospective randomised study in women undergoing primary hip replacement.

METHODS

Sixty consecutive female patients scheduled for primary hip replacement and suitable for PDAB were randomly assigned to one of 3 groups. Group I (EPO) and II (ANHD) received 600 U/kg rHuEPO s.c. and 100 mg iron saccharate i.v. on day 14 and, if needed, on day 7 before surgery. Additionally, in group II acute normovolaemic haemodilution (ANHD) was implemented after induction of anaesthesia. In group III (PDAB) conventional PDAB up to 3 U, without volume replacement but with concomitant oral iron therapy, was performed starting 4 weeks before surgery.

RESULTS

The blood conservation methods resulted in a comparable net gain of red cells in all 3 groups until the day of surgery. Because of the withdrawal of autologous blood, haemoglobin values before surgery were lower in the PDAB group than in the EPO and ANHD groups, and during surgery were lower in the PDAB and ANHD groups than in the rHuEPO-only group. Applying moderate ANHD in conjunction with preoperative rHuEPO treatment did not yield an incremental decrease in allogeneic transfusions. There was no difference between the groups in the number of patients who received allogeneic transfusions or in the total number of allogeneic units transfused.

CONCLUSIONS

Withdrawal of autologous blood is associated with lower pre- and intraoperative haemoglobin levels when compared to preoperative augmentation of red cell mass using rHu-EPO. As a measure to reduce allogeneic transfusion requirements, preoperative treatment with rHuEPO may be as effective as standard predeposit of autologous blood in women undergoing primary hip replacement, but requires less preoperative time.