Effects of acute normovolemic hemodilution and allogeneic blood transfusion on postoperative complications of oral and maxillofacial flap reconstruction: a retrospective study.

OBJECTIVE: Patients undergoing oral and maxillofacial flap reconstruction often need blood transfusions due to massive blood loss. With the increasing limitations of allogeneic blood transfusion (ABT), doctors are considering acute normovolemic hemodilution (ANH) because of its advantages. By comparing the differences in the (Δ) blood indices and postoperative complications of patients receiving ABT or ANH during the reconstruction and repair of oral and maxillofacial tumor flaps, this study's purpose was to provide a reference for the clinical application of ANH. METHODS: The clinical data of 276 patients who underwent oral and maxillofacial flap reconstruction from September 25, 2017, to October 11, 2021, in the Department of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, were retrospectively analyzed. According to the intraoperative blood transfusion mode, the patients were divided into two groups: ABT and ANH. The differences in the (Δ) blood indices and the incidence of postoperative complications between the groups were analyzed. RESULTS: Among the 276 patients who had ANH (124/276) and ABT (152/276), there were no differences in (Δ) Hb, (Δ) PT, or (Δ) FIB (P > 0.05), while (Δ) WBC, (Δ) PLT, (Δ) APTT and (Δ) D-dimer were significantly different (P < 0.05). The blood transfusion method was not an independent factor for flap crisis (P > 0.05). The wound infection probability in patients with high post-PTs was 1.953 times greater than that in patients with low post-PTs (OR = 1.953, 95% CI: 1.232 ∼ 3.095, P = 0.004). A normal or overweight BMI was a protective factor for pulmonary infection, and the incidence of pulmonary infection in these patients was only 0.089 times that of patients with a low BMI (OR = 0.089, 95% CI: 0.017 ∼ 0.462). Moreover, a high ASA grade promoted the occurrence of pulmonary infection (OR = 6.373, 95% CI: 1.681 ∼ 24.163). The blood transfusion mode (B = 0.310, ß = 0.360, P < 0.001; ANH: ln hospital stay = 2.20 ± 0.37; ABT: ln hospital stay = 2.54 ± 0.42) improved the length of hospital stay. CONCLUSION: Preoperative and postoperative blood transfusion (Δ) Hb, (Δ) PT, and (Δ) FIB did not differ; (Δ) WBC, (Δ) PLT, (Δ) APTT, and (Δ) D-dimer did differ. There was no difference in the effects of the two blood transfusion methods on flap crisis, incision infection or lung infection after flap reconstruction, but ANH resulted in a 3.65 day shorter average hospital stay than did ABT.

Exploration of the Clinical Effect of Different Autotransfusion Methods on Patients With Femoral Shaft Fracture Surgery.

OBJECTIVE: To explore the clinical effect of predeposit, salvage, and hemodilution autotransfusion on patients with femoral shaft fracture (FSF) surgery. METHODS: Selected patients with FSF were randomly divided into three groups: intraoperative blood salvage autotransfusion, preoperative hemodilution autohemotransfusion, and predeposit autotransfusion. Five days after the operation, the body temperature, heart rate, blood platelet (PLT), and hemoglobin (Hb) of patients were determined. The concentrations of EPO and GM-CSF in the three groups were calculated by ELISA. The content of CD14+ monocytes was calculated by FCM assay. The growth time and condition of the patient's callus were determined at the 30th, 45th, and 60th day after operation. Cox regression analysis was used to analyze the correlation between EPO, GM-CSF, CD14+ mononuclear content, callus growth, and autotransfusion methods. RESULTS: There were no statistically significant differences in body temperature and heart rate between the three groups (p > 0.05). PLT and Hb in the Predeposit group were markedly increased compared with that in the Salvage and Hemodilution groups. The concentrations of EPO and GM-CSF in the Predeposit group were markedly increased compared with that in the Salvage and Hemodilution groups. The content of CD14+ monocytes in the Predeposit group was significantly higher than that in the Salvage and Hemodilution groups. Predeposit autotransfusion promotes callus growth more quickly. CONCLUSION: Predeposit autotransfusion promoted the recovery of patients with FSF after the operation more quickly than salvage autotransfusion and hemodilution autotransfusion.

Bilateral nephrectomy impairs cardiovascular function and cerebral perfusion in a rat model of acute hemodilutional anemia.

Anemia and renal failure are independent risk factors for perioperative stroke, prompting us to assess the combined impact of acute hemodilutional anemia and bilateral nephrectomy (2Nx) on microvascular brain Po2 (PBro2) in a rat model. Changes in PBro2 (phosphorescence quenching) and cardiac output (CO, echocardiography) were measured in different groups of anesthetized Sprague-Dawley rats (1.5% isoflurane, n = 5-8/group) randomized to Sham 2Nx or 2Nx and subsequently exposed to acute hemodilutional anemia (50% estimated blood volume exchange with 6% hydroxyethyl starch) or time-based controls (no hemodilution). Outcomes were assessed by ANOVA with significance assigned at P < 0.05. At baseline, 2Nx rats demonstrated reduced CO (49.9 ± 9.4 vs. 66.3 ± 19.3 mL/min; P = 0.014) and PBro2 (21.1 ± 2.9 vs. 32.4 ± 3.1 mmHg; P < 0.001) relative to Sham 2Nx rats. Following hemodilution, 2Nx rats demonstrated a further decrease in PBro2 (15.0 ± 6.3 mmHg, P = 0.022). Hemodiluted 2Nx rats did not demonstrate a comparable increase in CO after hemodilution compared with Sham 2Nx (74.8 ± 22.4 vs. 108.9 ± 18.8 mL/min, P = 0.003) that likely contributed to the observed reduction in PBro2. This impaired CO response was associated with reduced fractional shortening (33 ± 9 vs. 51 ± 5%) and increased left ventricular end-systolic volume (156 ± 51 vs. 72 ± 15 µL, P < 0.001) suggestive of systolic dysfunction. By contrast, hemodiluted Sham 2Nx animals demonstrated a robust increase in CO and preserved PBro2. These data support the hypothesis that the kidney plays a central role in maintaining cerebral perfusion and initiating the adaptive increase in CO required to optimize PBro2 during acute anemia.NEW & NOTEWORTHY This study has demonstrated that bilateral nephrectomy acutely impaired cardiac output (CO) and microvascular brain Po2 (PBro2), at baseline. Following acute hemodilution, nephrectomy prevented the adaptive increase in CO associated with acute hemodilution leading to a further reduction in PBro2, accentuating the degree of cerebral tissue hypoxia. These data support a role for the kidney in maintaining PBro2 and initiating the increase in CO that optimized brain perfusion during acute anemia.

Effectiveness, safety and indications of acute normovolemic haemodilution in total knee arthroplasty.

Total knee arthroplasty (TKA) is the most cost-effective, and potent method for the treatment of end-stage knee osteoarthritis. Acute normovolemic haemodilution (ANH) can effectively replace the need for allogeneic transfusions due to the high amount of bleeding during TKA. However, more studies are needed to prove the efficacy and safety of ANH and to clarify its indications in the field of knee replacement. Medical records from June 1, 2019 to June 1, 2021 were searched and grouped according to inclusion and exclusion criteria. PART I: 58 patients with ANH during TKA were selected as the ANH group (n = 58), and 58 patients with allogeneic transfusion were chosen as the control group (n = 58). PART II: Patients with anaemia were divided into the ANH group (n = 18) and the control group (n = 12). PART I: The postoperative inflammatory index and serum albumin in the ANH group were significantly lower than those in the control group. No significant difference was observed in the theoretical loss of red blood cells, postoperative renal function, liver function, cardiac function and biochemical ion index between the two groups. The effective rate of ANH in the normal haemoglobin group was significantly lower than that in the anaemia group. PART II: In patients with anaemia, the theoretical loss of red blood cells in patients with ANH was less than that in the control group. The postoperative inflammation, renal function, liver function and cardiac function in the ANH group were better than those in the control group, and no significant difference was noted in biochemical ions and nutritional status indicators. This paper shows that ANH not only can replace allogeneic transfusion in TKA, especially in patients with anaemia, but also has lower inflammatory indicators than allogeneic transfusion. From a security perspective, the body's tolerance to ANH is within the body's compensation range.

Comparing acute normovolumic hemodilution with autologous platelet-rich plasma for blood preservation during aortic surgery : study protocol for a randomized controlled clinical trial.

BACKGROUND: Both acute normovolumic hemodilution (ANH) and autologous platelet-rich plasma (aPRP) have been demonstrated blood-protective effects in cardiac aortic surgery; however, the efficacies of the two methods have not been compared. This study aims to compare the effects of aPRP and ANH prior to aortic surgery on postoperative bleed and other outcomes. METHODS AND ANALYSIS: This is a prospective, single-center, double-blind controlled clinical trial including 160 patients randomized 1:1 to receive aPRP (test group) or autologous whole blood (ANH, control group). The primary objective is to compare the drainage volumes in the two groups at 24, 48, and 72 h postoperatively. Secondary outcomes include input of allogeneic blood and blood products and durations of aortic block, extracorporeal circulation, deep hypothermic arrest of circulation, tracheal extubation, hospital stay, requirement for secondary surgical hemostasis, and application of intra-aortic balloon pump or extracorporeal membrane oxygenation in the two groups. In addition, heart rate, systolic blood pressure, diastolic blood pressure, central venous pressure, and thromboelastography recorded before blood reservation (T1), after blood reservation (T2), before blood transfusion (T3), and after the blood is returned (T4) to the transfusion will be compared between the two groups of patients. DISCUSSION: This study will demonstrate if the use of aPRP could reduce the risk of bleeding after aortic surgery compared with ANH. The results are expected to have practical clinical applications in terms of more effective blood protection and shorter hospital stay. TRIAL REGISTRATION: This study was registered with the Chinese Clinical Trial Registry ( http://www.chictr.org.cn/ ) with the ID ChiCTR 1900023351.Registered on May 23, 2019. TRIAL STATUS: Recruiting start date: July 1, 2019; expected recruiting end date: July 1, 2024 Version number and date: Version 2 of 05-04-2019.

Treatments for Acute Nonarteritic Central Retinal Artery Occlusion: Findings From a Cochrane Systematic Review.

Many interventions for nonarteritic central retinal artery occlusion (CRAO) are associated with serious complications and little effect on visual outcomes. We report on the findings of a Cochrane systematic review that searched seven databases for peer-reviewed articles reporting on treatments for acute nonarteritic CRAO. We assessed six randomized controlled trials, including interventions such as tissue plasminogen activator (t-PA), isovolumic hemodilution, eyeball massage, intraocular pressure reduction, anticoagulation, vasodilation, oxygen inhalation, laser embolysis, transcorneal electrical stimulation, thrombolysis, pentoxifylline, and enhanced external counterpulsation. However, none of the randomized controlled trials demonstrated significant improvement in visual acuity at 1 month compared to observation, and some patients treated with t-PA experienced serious adverse effects including intracranial hemorrhage. Proposed interventions for acute nonarteritic CRAO may not be better than observation, but the evidence is uncertain. Larger, well-designed studies are necessary to determine the most effective management option for acute nonarteritic CRAO. [Ophthalmic Surg Lasers Imaging Retina 2023;54:650-653.].

Autologous versus allogeneic blood transfusion: A comparative study of the peri-operative outcomes in a tertiary care hospital in South India amidst the COVID-19 pandemic.

Autologous blood transfusion is known to have advantages over allogeneic transfusion. The COVID-19 pandemic intensified the already existing shortage of allogeneic blood supply. We carried out a study during this period with the aim to elicit the effects of autologous blood collection and transfusion, to compare the peri-operative outcomes of autologous and allogeneic transfusion practices and also to assess the influence of the autologous transfusion programme in the Blood Centre inventory. It was prospective observational comparative study among neurosurgical and vascular surgical patients in a tertiary care centre in South India. 141 patients were allocated into Group I (n = 71) who received autologous transfusion and those who received conventional allogeneic transfusion were clustered as Group II (n = 72) for analysis. We employed Acute Normovolemic Hemodilution (ANH), Pre-deposit Autologous Donation (PAD) and Intra-operative Cell Salvage (ICS) as various modalities for autologous blood collection. In our study, 43 (60.6%) from Group I received exclusive autologous blood transfusion, whereas 28 (39.4%) required additional allogeneic transfusion. No significant difference in hemoglobin, hematocrit, platelet count and INR were observed between the groups post transfusion. Significant difference was observed in the thoracoabdominal aortic aneurysm (TAAA) patients with respect to duration of ICU stay (2.7 ± 1.1 days in Group I and 6.2 ± 0.8 days in Group II; p = 0.002) and re-exploration due to bleeding (16.7% in Group I and 40% in Group II; p = 0.048). Autologous blood transfusion is safe and effective. It can be employed as routine practice and also during any acute shortage or pandemic.

Revisiting the benefits of isovolemic hemodilution red cell exchange for sickle cell disease.

BACKGROUND: Isovolemic hemodilution red cell exchange (IHD-RCE) is a modified form of the standard red cell exchange (STD-RCE), intended to reduce red cell requirements in patients with sickle cell disease (SCD). This retrospective crossover analysis of nine patients aims to add to the limited existing literature on IHD-RCE and address the equipoise regarding whether the benefits of (a) decreased RBC usage per exchange and (b) increased interprocedure interval (via lower fraction of cells remaining, FCR) can be observed at the same time, in the same patient. METHODS: At a single center, we identified 37 patients with SCD undergoing chronic RCE between 2014 and 2021. We excluded those patients who did not have at least six consecutive procedures of each type (STD- and IHD-RCE), arriving at nine patients for analysis. RESULTS: When using greater decreases in hematocrit than previously published, we did not find that IHD-RCE resulted in any clinically apparent adverse events. We did find greater decreases in diastolic blood pressure and increases in heart rate in some patients, as compared to STD-RCE. After correcting for total blood volume, seven of the nine patients had significantly reduced red cell requirements with each IHD-RCE. Because the pattern of achieving a lower FCR than programmed was seen to an equal extent with both IHD-RCE and STD-RCE, none of the nine patients showed any statistical difference in actual FCR between procedure types. DISCUSSION: Our data do not support the observation of both IHD-RCE benefits, decreased red cell usage per exchange and lower FCR/increased interprocedure interval, simultaneously.

Blood volume estimation in cardiac surgery - A comparative analysis.

INTRODUCTION: This paper seeks to identify which of three published formulas used for estimating the blood volume of normal human subjects correlates most closely with blood volumes measured in a published study where erythrocyte volume was determined by a method using 51Cr and a nonradioactive dye was used to determine the plasma volume. METHODS: Blood volumes predicted by three published algorithms were compared with blood volume estimates from a study by Retzlaff et al. using the two-tailed Wilcoxon signed rank test and a robust version of the Bland-Altman test. RESULTS: When applied to a sample of normal subjects selected from Mayo Clinic personnel and patients, the Nadler formula correlated more closely with blood volume measured using a radio nucleotide technique than did the Allen formula or one based on a saline haemodilution technique. CONCLUSIONS: The Nadler formula correlated more closely with blood volume measurements derived from Retzlaff's study than the other formulas for estimating blood volume in a population with height and weight distribution more consistent with that seen in North America. It should be used in preference to the Allen formula for estimating blood volume in adult patients currently undergoing cardiac surgical procedures. Saline haemodilution techniques used to measure blood volume require validation against more recently developed nuclear medicine techniques using statistical methods other than regression analysis. Until validated, they should be used with caution for estimating blood volume in adult patients currently undergoing cardiac surgical procedures. If a formula using height, weight and sex is used to estimate blood volume in the context of cardiac surgery, then it must be derived using a much more comprehensive sample of the population to which it is applied than has occurred to date. In particular, it should include broader distributions of height, weight and the presence or absence and type of significant valvular disease.

Transfusion-free Strategies in Liver and Pancreatic Surgery: A Predictive Model of Blood Conservation for Transfusion Avoidance in Mainstream Populations.

OBJECTIVE: The objective of this study is to (1) describe the techniques and prove the feasibility of performing complex hepatobiliary and pancreatic surgery on a Jehovah Witness (JW) population.  (2) Describe a strategy that offsets surgical blood loss by the manipulation of circulating blood volume to create reserve whole blood upon anesthesia induction. BACKGROUND: Major liver and pancreatic resections often require operative transfusions. This limits surgical options for patients who do not accept major blood component transfusions. There is also growing recognition of the negative impact of allogenic blood transfusions. METHODS: A 23-year, single-center, retrospective review of JW patients undergoing liver and pancreatic resections was performed. We describe perioperative management and patient outcomes. Acute normovolemic hemodilution (ANH) is proposed as an important strategy for offsetting blood losses and preventing the need for blood transfusion. A quantitative mathematical formula is developed to provide guidance for its use. RESULTS: One hundred one major resections were analyzed (liver n=57, pancreas n=44). ANH was utilized in 72 patients (liver n=38, pancreas n=34) with median removal of 2 units that were returned for hemorrhage as needed or at the completion of operation. There were no perioperative mortalities. Morbidity classified as Clavien grade 3 or higher occurred in 7.0% of liver resection and 15.9% of pancreatic resection patients. CONCLUSIONS: Deliberate perioperative management makes transfusion-free liver and pancreatic resections feasible. Intraoperative whole blood removal with ANH specifically preserves red cell mass, platelets, and coagulation factors for timely reinfusion. Application of the described JW transfusion-free strategy to a broader general population could lessen blood utilization costs and morbidities.

Effects of acute normovolemic hemodilution on allogeneic blood transfusion & coagulation in orthognathic surgery: A randomized study.

BACKGROUND: Acute normovolemic hemodilution (ANH) is one of the important techniques predominantly used in cardiac, hepatic, and vascular surgery for decreasing allogeneic blood transfusion. However, the effect of ANH in orthognathic surgery has been rarely studied. Therefore, this study aims to assess the ANH-mediated reduction in the allogeneic red blood cell transfusion for orthognathic surgery patients. STUDY DESIGN AND METHODS: In this single-center study, 18-80 years old patients were recruited. Patients with hemoglobin ≥11 g/dL and normal coagulation function were randomly divided into ANH or standard treatment group. RESULTS: Ninety six patients underwent ANH, and 101 patients received standard treatment. No differences in demographic or major pre-operative characteristics were observed between the two groups. One patient in the ANH and three patients in the standard treatment group received allogeneic blood [3(2.97%) vs. 1(1.16%), control vs. ANH, p = .395]. Multivariate logistic regression analysis revealed that ANH treatment was not associated with transfusion of allogeneic blood (p = .763). After retransfusing autologous blood, PT and APTT in the ANH group significantly increased compared to standard treatment group (PT: -1.73 ± 1.09 vs. -2.15 ± 1.06, p = .035; APTT: -6.39 ± 5.76 vs. -8.16 ± 5.70, p = .031; control vs. ANH). No significant differences between the two groups were observed for changes in coagulation parameters at first postoperative day. However, platelet counts in the ANH group decreased compared to the standard group. No significant difference in major adverse outcomes was observed between the two groups. CONCLUSION: ANH did not reduce the incidence of allogeneic transfusion in patients undergoing orthognathic surgery.

Exercise-related hemoconcentration and hemodilution in hydrated and dehydrated athletes: An observational study of the Hungarian canoeists.

Hemoconcentration during exercise is a well-known phenomenon, however, the extent to which dehydration is involved is unclear. In our study, the effect of dehydration on exercise-induced hemoconcentration was examined in 12 elite Hungarian kayak-canoe athletes. The changes of blood markers were examined during acute maximal workload in hydrated and dehydrated states. Dehydration was achieved by exercise, during a 120-minute extensive-aerobic preload. Our research is one of the first studies in which the changes in blood components were examined with a higher time resolution and a wider range of the measured parameters. Hydration status had no effect on the dynamics of hemoconcentration during both the hydrated (HS) and dehydrated (DHS) load, although lower maximal power output were measured after the 120-minute preload [HS Hemoglobin(Hgb)Max median 17.4 (q1 17.03; q3 17.9) g/dl vs. DHS HgbMax median 16.9 (q1 16.43; q3 17.6) g/dl (n.s); HS Hematocrit(Hct)Max 53.50 (q1 52.28; q3 54.8) % vs. DHS HctMax 51.90 (q1 50.35; q3 53.93) % (n.s)]. Thirty minutes after the maximal loading, complete hemodilution was confirmed in both exercises. Dehydration had no effect on hemoconcentration or hemodilution in the recovery period [HS HgbR30' 15.7 (q1 15.15; q3 16.05) g/dl (n.s.) vs. DHS HgbR30' 15.75 (q1 15.48; q3 16.13) g/dl (n.s.), HS HctR30' 48.15 (q1 46.5; q3 49.2) % vs. DHS HctR30' 48.25 (q1 47.48; q3 49.45) % (n.s.)], however, plasma osmolality did not follow a corresponding decrease in hemoglobin and hematocrit in the dehydrated group. Based on our data, metabolic products (glucose, lactate, sodium, potassium, chloride, bicarbonate ion, blood urea nitrogen) induced osmolality may not play a major role in the regulation of hemoconcentration and post-exercise hemodilution. From our results, we can conclude that hemoconcentration depends mainly on the intensity of the exercise.

Estradiol dominance induces hemodilution and mild hematological alterations in mifepristone-treated rats.

We examined that an estradiol-dominant state against progesterone could affect hematological parameters through hemodilution because estradiol is known to increase plasma volume via oncotic pressure. We performed a 2- and 3-week repeated oral dose study with mifepristone, a progesterone receptor antagonist, in female rats and examined erythrocyte counts, hemoglobin, hematocrit, plasma volume, levels of estradiol and progesterone, water intake, and water loss. Mifepristone treatment decreased some hematological parameters mildly and increased plasma volume. There were no remarkable changes in the balance of water intake and water loss through urination. Both estradiol and progesterone levels and the ratio of estradiol to progesterone increased. Therefore, our findings indicate that repeated mifepristone treatment increases estradiol levels and plasma volume, resulting in lower erythrocyte counts, hemoglobin, and hematocrit. The present study proved the possible contribution of estradiol to understanding the toxicological significance of mifepristone-induced hemodilution.

Effects of room temperature and cold storage on the metabolic and haemostatic properties of whole blood for acute normovolaemic haemodilution.

BACKGROUND: Acute normovolaemic haemodilution (ANH), as a blood-conservation technique, avoids the need for allogeneic blood transfusions. The historic practice of cold-storing type-O whole blood (WB) in military fields popularised the transfusion of refrigerated WB to treat acute bleeding. In this study, we compared the effects of room temperature (RT) and refrigeration up to 24 hours on the coagulation properties of WB for ANH. MATERIALS AND METHODS: Each WB sample, collected from 12 male volunteers, was divided into two parts, one stored at RT and the other refrigerated for 24 hours. Complete blood counts (CBC), blood gas levels, and coagulation profiles were measured, and rotational thromboelastometry (ROTEM) measurements were performed at the initial collection time point (baseline) and at 6, 12, and 24 hours after initial collection. RESULTS: The preservation of platelet aggregation response induced by arachidonic acid and adenosine diphosphate was better in cold-stored WB compared to that in RT-stored WB. The platelet aggregation response induced by thrombin receptor-activating peptide 6 was significantly decreased in all samples after 24 hours of storage when compared with that at baseline. The lactate levels in WB stored at RT increased significantly after 6 hours of storage compared to that of cold-stored samples. There were no significant differences in CBC, coagulation parameters, and ROTEM variables between the cold-stored and RT-stored WB samples. CONCLUSION: WB for ANH stored in the refrigerator showed better metabolic characteristics after 6 hours of storage and better aggregation response after 12 hours of storage than WB stored at RT.

Hemodilution in high-risk cardiac surgery: Laboratory values, physiological parameters, and outcomes.

BACKGROUND: Acute normovolemic hemodilution (ANH) is a blood conservation strategy in cardiac surgery, predominantly used in coronary artery bypass graft (CABG) and/or valve procedures. Although higher complexity cardiac procedures may benefit from ANH, concerns for hemodynamic instability, and organ injury during hemodilution hinder its wider acceptance. Laboratory and physiological parameters during hemodilution in complex cardiac surgeries have not been described. STUDY DESIGN AND METHODS: This observational cohort (2019-2021) study included 169 patients who underwent thoracic aortic repair, multiple valve procedure, concomitant CABG with the aforementioned procedure, and/or redo sternotomies. Patients who received allogeneic blood were excluded. Statistical comparisons were performed between ANH (N = 66) and non-ANH controls (N = 103). ANH consisted of removal of blood at the beginning of surgery and its return after cardiopulmonary bypass. RESULTS: Intraoperatively, the ANH group received more albumin (p = .04) and vasopressor medications (p = .01), while urine output was no different between ANH and controls. Bilateral cerebral oximetry (rSO2 ) values were similar before and after hemodilution. During bypass, rSO2 were discretely lower in the ANH versus control group (right rSO2 p = .03, left rSO2 p = .05). No differences in lactic acid values were detected across the procedural continuum. Postoperatively, no differences in extubation times, intensive care unit length of stay, kidney injury, stroke, or infection were demonstrated. DISCUSSION: This study suggests hemodilution to be a safe and comparable blood conservation technique, even without accounting for potential benefits of reduced allogenic blood administration. The study may contribute to better understanding and wider acceptance of ANH protocols in high-risk cardiac surgeries.

The impact of crystalloid versus colloid on coagulation as measured by thromboelastometry in term parturients: an in vitro study.

OBJECTIVE: A pilot study to examine the impact of crystalloid versus albumin hemodilution in vitro on coagulation using thromboelastometry in pregnant patients. METHODS: This prospective, observational pilot study included seventy-six pregnant patients at term (≥37 weeks) without history of bleeding or clotting disorder or on anticoagulation. Blood was collected and diluted with either Plasma-Lyte or albumin at the following levels: 0%, 20%, 25%, 30%, 35%, 40%, 45%, 55%, 60%, 65%, 70%, 75%, 80%. Thromboelastometry was performed to assess for coagulation changes. RESULTS: There was a small, statistically significant difference in the FIBTEM A5 between the Plasma-Lyte and albumin samples. However, the predicted probability of coagulopathy, using FIBTEM A5 less than 12 mm, was not different between the groups at any dilution. There was no difference in EXTEM clotting time at low-moderate levels of hemodilution. At dilutions above 40%, the albumin group had a significantly greater prolongation in clotting time compared to the Plasma-Lyte group. CONCLUSION: When albumin is used at low-moderate levels of hemodilution in vitro in parturients there is no additional risk of coagulopathy compared to hemodilution with crystalloid. Given that colloids are frequently used to restore intravascular volume during massive hemorrhage, these results support that during early stages of hemorrhage, albumin may not contribute to additional coagulopathy beyond that of hemodilution, although further in vivo studies are needed.

Acute Normovolemic Hemodilution-assisted Terminal Blood Procurement in Swine for Ex Vivo Organ Perfusion.

Swine (Sus scrofa domesticus) are commonly used large animal subjects for the study of disease and preclinical therapies. Organ machine perfusion is a therapy that has gained momentum as a research platform for the study of ex vivo organ preservation and therapeutics. However, complex perfusion circuits and research protocols often require large volumes of blood as perfusate. Here, we report a technique for increasing terminal blood yield during swine organ and blood procurement; our method involves acute normovolemic hemodilution and exsanguination via the femoral artery. We collected a total of 47 ± 4 mL/kg of blood and 4.3 ± 0.6 g/kg of hemoglobin, representing 73% ± 6% of the estimated blood volume and 64% ± 8% of the total estimated intravascular hemoglobin (n = 4). Neither pH, lactate, nor pO2 levels changed significantly during blood procurement. Acute normovolemic hemodilution is an effective method for increasing RBC and hemoglobin yield during blood procurement in swine.

Albumin Infusion in Critically Ill COVID-19 Patients: Hemodilution and Anticoagulation.

Hypercoagulation is one of the major risk factors for ICU treatment, mechanical ventilation, and death in critically ill patients infected with SARS-CoV-2. At the same time, hypoalbuminemia is one risk factor in such patients, independent of age and comorbidities. Especially in patients with severe SARS-CoV-2-infection, albumin infusion may be essential to improve hemodynamics and to reduce the plasma level of the main marker of thromboembolism, namely, the D-dimer plasma level, as suggested by a recent report. Albumin is responsible for 80% of the oncotic pressure in the vessels. This is necessary to keep enough water within the systemic circulatory system and for the maintenance of sufficient blood pressure, as well as for sufficient blood supply for vital organs like the brain, lungs, heart, and kidney. The liver reacts to a decrease in oncotic pressure with an increase in albumin synthesis. This is normally possible through the use of amino acids from the proteins introduced with the nutrients reaching the portal blood. If these are not sufficiently provided with the diet, amino acids are delivered to the liver from muscular proteins by systemic circulation. The liver is also the source of coagulation proteins, such as fibrinogen, fibronectin, and most of the v WF VIII, which are physiological components of the extracellular matrix of the vessel wall. While albumin is the main negative acute-phase protein, fibrinogen, fibronectin, and v WF VIII are positive acute-phase proteins. Acute illnesses cause the activation of defense mechanisms (acute-phase reaction) that may lead to an increase of fibrinolysis and an increase of plasma level of fibrinogen breakdown products, mainly fibrin and D-dimer. The measurement of the plasma level of the D-dimer has been used as a marker for venous thromboembolism, where a fourfold increase of the D-dimer plasma level was used as a negative prognostic marker in critically ill SARS-CoV-2 hospitalized patients. Increased fibrinolysis can take place in ischemic peripheral sites, where the mentioned coagulation proteins can become part of the provisional clot (e.g., in the lungs). Although critically ill SARS-CoV-2-infected patients are considered septic shock patients, albumin infusions have not been considered for hemodynamic resuscitation and as anticoagulants. The role of coagulation factors as provisional components of the extracellular matrix in case of generalized peripheral ischemia due to hypoalbuminemia and hypovolemia is discussed in this review.

Effects of whole blood storage in a polyolefin blood bag on platelets for acute normovolemic hemodilution.

Acute normovolemic hemodilution (ANH) is a potential transfusion method for platelets, as well as for red blood cells. However, previous studies have shown that whole blood storage in ANH decreases platelet aggregability by 14.7-76.3% and that this decrease is not recovered by reinfusion. We investigated whether a new whole blood storage method for 6 h using a polyolefin bag, based on the platelet concentrates storage method, would maintain platelet function better than the conventional method using a polyvinyl chloride bag. We demonstrated that storage of whole blood in a polyolefin bag maintained ADP-induced aggregation rates at more than twofold higher than those in a polyvinyl chloride bag, and also significantly suppressed P-selectin expression, a platelet activation marker (ADP-induced aggregation rates: 24.6 ± 5.1% vs. 51.7 ± 11.5%, p = 0.002; P-selectin expression; 50.3 ± 8.4MFI vs. 31.6 ± 9.3MFI, p = 0.018). These results could be attributed to the high gas permeability of polyolefin, which lowered PCO2 and maintained a high pH with or without agitation. There were no significant changes in platelet count and red blood cell parameters due to the storage methods. Our results suggest that ANH using polyolefin bags is advantageous in improving hemostatic function compared to the conventional method.

The Use of Acute Normovolemic Hemodilution in Clipping Surgery for Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: The occurrence of coronavirus disease 2019 (COVID-19) has overwhelmed the blood supply chain worldwide and severely influenced clinical procedures with potential massive blood loss, such as clipping surgery for aneurysmal subarachnoid hemorrhage (aSAH). Whether acute normovolemic hemodilution (ANH) is safe and effective in aneurysm clipping remains largely unknown. METHODS: Patients with aSAH who underwent clipping surgery within 72 hours from bleeding were included. The patients in the ANH group received 400 mL autologous blood collection, and the blood was returned as needed during surgery. The relationships between ANH and perioperative allogeneic blood transfusion, postoperative outcome, and complications were analyzed. RESULTS: Sixty-two patients with aSAH were included between December 2019 and June 2020 (20 in the ANH group and 42 in the non-ANH group). ANH did not reduce the need of perioperative blood transfusion (3 [15%] vs. 5 [11.9%]; P = 0.734). However, ANH significantly increased serum hemoglobin levels on postoperative day 1 (11.5 ± 2.5 g/dL vs. 10.3 ± 2.0 g/dL; P = 0.045) and day 3 (12.1 ± 2.0 g/dL vs. 10.7 ± 1.3 g/dL; P = 0.002). Multivariable analysis indicated that serum hemoglobin level on postoperative day 1 (odds ratio, 0.895; 95% confidence interval, 0.822-0.973; P = 0.010) was an independent risk factor for unfavorable outcome, and receiver operating characteristic curve analysis showed that it had a comparable predictive power to World Federation of Neurosurgical Societies grade (Z = 0.275; P > 0.05). CONCLUSIONS: ANH significantly increased postoperative hemoglobin levels, and it may hold the potential to improve patients' outcomes. Routine use of ANH should be considered in aneurysm clipping surgery.