Changes in hematocrit based on incremental blood sampling: mathematical models perform poorly

PURPOSE: Excessive blood sampling, with its inherent risks, is of growing concern among clinicians. We performed this study to measure the changes in hematocrit (Hct) during a laboratory investigation where multiple blood samples are collected. The performance of a simple mathematical model, used in clinical practice to predict Hct changes, is evaluated. METHODS: Eight healthy male volunteers participated in this study. The equation Hct(f) = Hct(i)*(EBV-BL)/EBV is used to predict changes in Hct. Where Hct(f) and Hct(i) are, respectively, the final and initial Hct, EBV is the estimated blood volume and BL is the blood loss. RESULTS: Thirty-five pharmacokinetic samples per subject were collected totalling 314 mL of BL.The Hct decreased from 44.2% +/- 2.2% to 39.9% +/- 2.5% (P = 0.001). On average, model predictions tended to have a discrete tendency to underestimate the Hct changes (-0.5% points of bias). While the predictions of the Hct were very accurate in 50% of the subjects, the discrepancy of the Hct predictions was clinically significant in the other 50% of the subjects. CONCLUSION: Consistent with the model prediction, this study demonstrated a significant reduction in the Hct values in healthy subjects undergoing incremental phlebotomy. On average, the model successfully predicted the decrease in Hct. However, the inter- and intra-individual variabilities in the Hct changes are clinically significant. In clinical settings, which are not well controlled environments, the variability is likely to be greater and the clinical use of the model cannot replace the need to monitor the Hct.     

Intraoperative use of platelet-plasmapheresis in vascular surgery

STUDY OBJECTIVE: To determine, in a pilot study, whether pheresis of plasma and platelets before surgical blood loss, with reinfusion of the autologous plasma and platelets after completion of the aortic reconstruction, will result in decreased bleeding and decreased transfusion of allogenic blood components in patients undergoing elective aortic reconstruction. DESIGN: Randomized study. SETTING: University medical center. INTERVENTIONS: Patients were randomized to perioperative (acute) platelet plasmapheresis (APP group) versus conventional blood component therapy (control group). In the APP group, blood was withdrawn after induction of anesthesia, to sequester approximately 300 mL of platelet rich plasma (PRP); platelet poor plasma (PPP) and red blood cells (RBC) were sequestered as well. An autotransfusion device was used to collect and re-infuse autologous RBC during the course of the operation in both groups. After completion of the aortic reconstruction, autologous PRP and PPP were re-infused in the APP group. Blood loss, volume of blood component transfusions, and preoperative and postoperative hemoglobin (Hb), hematocrit (Hct), platelet, international normalized ratio (INR), and activated partial thromboplastin time (aPTT) were recorded. MEASUREMENTS AND MAIN RESULTS: There was no difference between groups in demographics, preoperative laboratory values, or surgical procedures, although more patients were treated for aneurysms (73% vs. 60%) and fewer for occlusive disease (20% vs. 40%) in the control versus APP group. Also, there were no differences between the control and APP groups in duration of operation, blood loss, volume of colloid infused, or volume of allogenic RBC and plasma transfused. Patients in the APP group received a greater volume of crystalloid solution (9.1 +/- 3.4 L vs. 6.8 +/- 3.0 L; p = 0.002), but fewer units of allogenic platelets than the control group (0.7 +/- 1.0 units vs. 0.2 +/- 0.4 units; p < 0.04). There were no differences in postoperative Hb, Hct, INR, aPTT, or fibrinogen. The platelet count was lower in the APP group than in the control group (123 +/- 40 x 10(3)/mm(3) vs. 182 +/- 51 x 10(3)/mm(3); p = 0.004). CONCLUSIONS: Perioperative platelet plasmapheresis led to fewer allogenic platelet transfusions in patients undergoing elective aortic reconstruction. However, there was no decrease in blood loss and no reduction in transfusion of allogenic RBC or plasma. Perioperative platelet plasmapheresis is not recommended for routine use in elective aortic reconstruction.     

学龄前儿童先天性脊柱侧凸矫形手术围术期输血的相关因素分析——一项单中心回顾性分析

目的回顾性分析学龄前儿童（≤72个月）行先天性脊柱侧凸矫形手术围术期血液管理的临床特点及相关影响因素。方法针对2年以来行先天性脊柱侧凸矫形手术的110例学龄前儿童（≤72个月）相关资料进行回顾性分析,组间比较采用t检验,组内比较采用重复测量的方差分析,多元Logistic回归分析被用来确定异体红细胞输注的独立预测因子。结果共有91例患儿（83％）术中输入异体红细胞,与术中异体红细胞输入量存在明显相关性的因素有患儿的体重、术前Cobb角、融合节段、手术时间、截骨数量、失血量以及术前血红蛋白（hemoglobin,Hb）浓度、红细胞比容（hematocrit,Hct）、血小板（bloodplatelet,Pit）计数,其中独立因素有Cobb角、截骨数量、术前Hb浓度、Hct、Pit计数。输血患儿与未输血患儿比较,术中截骨率、术中出血量和术后24h伤口引流量显著增加,术后住院时间也明显延长。结论可作为围术期输血评估的独立因素有Cobb角、截骨数量、术前Hb浓度、Hct、Plt计数,而与患儿的年龄、体重、融合节段及手术时间无明显相关性,有助于对学龄前儿童先天性脊柱侧凸矫形手术围术期输血需求的早期识别和准确评估,保证患儿的生命安全。     

Preoperative blood volume deficit influences blood transfusion requirements in females and males undergoing coronary bypass graft surgery

STUDY OBJECTIVE: To evaluate whether preoperative blood volume and postoperative blood loss influence blood transfusion in females and males undergoing coronary artery bypass graft (CABG) surgery. DESIGN: Prospective study. SETTING: Anesthesiology department of a teaching hospital. PATIENTS: 57 CABG patients (21 females and 36 males). MEASUREMENTS: Blood volume was determined using the radioactivity dilution method. Preoperatively, each patient received intravenous (IV) injection of 1 mL Albumin I(131) tracer having 25 microcuries of radioactivity. Five-milliliter blood samples were collected at different intervals. From these samples, hematocrit (Hct) value, preoperative total blood volume, red blood cell (RBC) volume, and plasma volume were determined. Postoperatively, some consenting patients received another 1 mL dose of the tracer, and the postoperative blood volumes were determined. If a patient received a blood transfusion, the units of packed red blood cells (PRBCs), platelets, or fresh frozen plasma (FFP) transfused were recorded. For each patient we recorded the gender, age, weight, height, body surface area (BSA), preoperative Hct, duration of surgery, and discharge Hct. RESULTS: Preoperatively, the mean total blood volume, RBC volume, and plasma volume, respectively, were 2095 mL/m(2), 631 mL/m(2), and 1,465 mL/m(2) in females; and 2,580 mL/m(2), 878 mL/m(2), and 1,702 mL/m(2) in males. The preoperative blood volumes were significantly lower (p < 0.01) in females than in males. There was no significant difference between males and females in the extent of blood loss during CABG. Intraoperatively, females received PRBC transfusion of 1.38 units, significantly more (p < 0.01) than the 0.39 units received by males. During the entire hospital stay, females received 4.33 units of PRBC, significantly more than (p < 0.02) the 1.33 units received by males. Significantly more (p < 0.01) females (12 of 21) received intraoperative PRBC transfusion than did males (6 of 36). Multiple logistic regression analysis of the data showed that PRBC transfusion was significantly correlated with the preoperative total blood volume and RBC volume. CONCLUSION: The greater need for blood transfusion in females than in males during CABG is primarily attributable to significantly lower preoperative total blood volume and RBC volume in females.     

Hypothermia is an independent predictor of mortality in ruptured abdominal aortic aneurysms

Hypothermia is known to significantly increase mortality in trauma patients, but the effect of hypothermia on outcomes in ruptured abdominal aortic aneurysms (RAAA) has not been evaluated. The authors reviewed their experience from 1990 to 1999 in 100 consecutive patients who presented with RAAA and survived at least to the operating room for surgical treatment. There were 70 men and 30 women, with a mean overall age of 74 +/-8 years. Overall mortality was 47%. Univariate ANOVA (analysis of variants) showed significant correlation with mortality for decreased intraoperative temperature, decreased intraoperative systolic blood pressure, increased intraoperative base deficit, increased blood volume transfused, increased crystalloid volume (all p < 0.001); decreased preoperative hemoglobin (p = 0.015); and increased age (p = 0.026). Patient sex, initial preoperative temperature, preoperative systolic blood pressure, and operating room time were not correlated with mortality in the univariate analysis. Using these same clinical variables, multiple logistic regression analysis showed only 2 factors independently correlated with mortality: lowest intraoperative temperature (p = 0.006) and intraoperative base deficit (p = 0.009). The mean lowest temperature for survivors was 35 +/-1 degrees C and for nonsurvivors 33 +/-2 degrees C (p < 0.001). When patients were grouped by lowest intraoperative temperature, those whose temperature was < 32 degrees C (n = 15) had a mortality rate of 91%, whereas patients with a temperature between 32 and 35 degrees C (n = 50) had a mortality rate of 60%. In the group that remained at or > 35 degrees C (n = 35) the mortality rate was only 9%. A nomogram of predicted mortality versus temperature was constructed from these data and showed that for temperatures of 36, 34, and 32 degrees C the predicted mortality was 15%, 49%, and 84%, respectively. The authors conclude that hypothermia is a strong independent contributor to mortality in patients with ruptured abdominal aortic aneurysms and that very aggressive measures to prevent hypothermia are warranted during the resuscitation and treatment of these patients.     

老年股骨颈骨折半髋关节置换术后输血预测模型的建立

目的分析老年股骨颈骨折患者半髋关节置换术后输血的危险因素,建立老年股骨颈骨折患者半髋关节置换术后输血的列线图预测模型。 方法回顾性分析2016年1月至2020年6月江苏省苏北人民医院股骨颈骨折行半髋关节置换术的235例患者。纳入标准：年龄≥60岁,新发、单侧股骨颈骨折;手术方式为半髋关节置换术。排除标准：合并全身其他骨折;术前输血;合并凝血功能障碍或者其他血液系统疾病;身体状况较差无法耐受手术者;病历资料不完整者。根据术后是否输血,分为输血组和未输血组。收集其临床资料,包括性别、年龄、身体质量指数(BMI)、高血压、糖尿病、冠心病、脑卒中、吸烟、饮酒、术前血红蛋白(Hb)、术前血小板(PLT)、术前白蛋白、术前凝血功能、术前抗凝药使用、骨折Garden分型、受伤至手术时间、假体类型、术后是否引流、术后血钙浓度、美国麻醉师协会(ASA)分级、麻醉方式、手术时间、术中出血量等。应用单因素和多因素logistic回归模型筛选术后输血的独立危险因素;通过R软件构建列线图预测模型,并绘制出受试者工作特征(ROC)曲线及校准曲线来评价模型的区分度和准确度。 结果本研究共纳入235例研究对象,输血组60例,输血率为25.5%。两组患者在术前Hb(χ²＝62.831)、麻醉方式(χ²＝6.539)、手术时间(χ²＝79.392)、术中出血量(χ²＝74.515)、假体类型(χ²＝5.631)方面的组间差异有统计学意义(均为P<0.05)。多因素logistic回归模型分析显示：术前Hb水平(Hb<100 g/L)、手术时间延长(时间≥60 min)、术中出血量增多(出血量≥200 ml)是老年股骨颈骨折患者半髋关节置换术后输血的独立危险因素(均为P<0.05)。列线图预测模型曲线下面积AUC为0.95,校准曲线的斜率接近1,提示该预测模型具有良好的区分度和准确度。 结论基于术前血红蛋白、手术时间、术中出血量这3项独立危险因素构建的老年股骨颈骨折患者半髋关节置换术后输血预测的列线图模型具有良好的区分度和准确度,望为临床上早期甄别术后高风险输血患者提供指导意义。     

Postoperative autotransfusion in primary knee replacement surgery

OBJECTIVE: To assess the efficacy of postoperative autologous transfusion to reduce homologous blood transfusion needs in primary knee replacement surgery. PATIENTS AND METHODS: A prospective study was carried out in 33 consecutive patients with diagnoses of arthrosis scheduled for primary knee replacement surgery with postoperative autotransfusion using a CBCII Constavac-Stryker (Stryker Instruments, Michigan, USA) recovery system from June through October 2002. We analyzed patient age, sex, preoperative and postoperative (24 hours) hemoglobin and hematocrit values, autologous blood reinfused and homologous blood transfusion incidence rate (if hematocrit was below 25%). RESULTS: Of the 33 patients receiving postoperative autotransfusion, one also needed homologous blood transfusion (3%). The mean volume of filtered whole blood reinfused was 538.63+/-261.23 mL, 1100 mL being the largest volume reinfused. We observed no complications related to use of autotransfusion devices during the perioperative period. CONCLUSIONS: Postoperative autotransfusion as the only blood salvage technique in primary knee prosthesis surgery nearly eliminates homologous transfusion needs. In addition, it is a safe, simple procedure and has replaced our hospital's preoperative autologous transfusion procedure.     

Influence of intraoperative fluid volume on cardiopulmonary bypass hematocrit and blood transfusions in coronary artery bypass surgery

A hematocrit (Hct) of less than 25% during cardiopulmonary bypass (CPB) and transfusion of homologous packed red blood cells (PRBC) are each associated with an increased probability of adverse events in cardiac surgery. Although the CPB circuit is a major contributor to hemodilution intravenous (IV) fluid volume may also significantly influence the level of hemodilution. The objective of this study was to explore the influence of asanguinous IV fluid volume on CPB Hct and intraoperative PRBC transfusion. After Institutional Review Board approval, a retrospective chart review of 90 adult patients that had undergone an elective, isolated CABG with CPB was conducted. Regression analysis was used to determine if pre-CPB fluid volume was associated with the lowest CPB Hct and the incidence of an intraoperative PRBC transfusion. In separate multivariate analyses, higher pre-CPB fluid volume was associated with lower minimum CPB Hct (p < .0001), and higher minimum CPB Hct was associated with a decreased probability of PRBC transfusion (p < .0001). Compared to patients that received <1600 mL (n = 55) of pre-CPB fluid, those that received >1600 mL (n = 35) had a decreased mean low CPB Hct (22.4% vs 25.6%, p < .0001), an increased incidence of a CPB Hct <25% (74% vs. 38%, p = .0008) and PRBC transfusion (60% vs. 16%, p < .0001), and increased median PRBC units transfused (2.0 vs 1.0, p = .1446) despite no significant difference in gender, age, patient size, baseline Hct, or CPB prime volume. Patients that received a PRBC transfusion (n = 30) received a significantly higher volume of pre-CPB fluid than nontransfused patients (1800 vs. 1350 mL, p = .0039). These findings suggest that pre-CPB fluid volume can significantly contribute to hemodilutional anemia in cardiac surgery. Optimizing pre-CPB volume may preserve baseline Hct and help limit intraoperative hemodilution.     

Fast-track cardiac anesthesia in patients with sickle cell abnormalities.

We conducted a retrospective review of 10 patients with sickle cell trait (SCT) and 30 patients (cohort control) without SCT undergoing first-time coronary artery bypass graft surgery with cardiopulmonary bypass. Demographic, perioperative management, and outcome data were collected. Both groups were matched according to age, weight, duration of surgery, and preoperative hemoglobin (Hb) concentration. Distribution of gender, medical conditions, pharmacological treatment, and preoperative left ventricular function were similar between the groups. The comparisons were analyzed in respect to postoperative blood loss and transfusion rates, as well as duration of intubation, intensive care unit, and hospital length of stay (LOS). All patients underwent fast-track cardiac anesthesia. A combination of cold crystalloid and blood cardioplegia was used. The lowest nasopharyngeal temperature was 33 degrees C. There were no episodes of significant hypoxemia, hypercarbia, or acidosis. None of the patients had sickling crisis during the perioperative period. The postoperative blood loss was 687 +/- 135 vs 585 +/-220 mL in the SCT and control groups, respectively. The trigger for blood transfusion during cardiopulmonary bypass was hematocrit <20% and Hb <75 g/L postoperatively. Three SCT patients (30%) and 10 control patients (33%) received a blood transfusion. Median extubation time was 4.0 vs 3.9 h; intensive care unit LOS was 27 vs 28 h; and hospital LOS was 6.0 vs 5.5 days in the SCT and control groups, respectively. There were no intraoperative deaths. One patient in the SCT group died from multiorgan failure 2 mo after surgery. IMPLICATIONS: Fast-track cardiac anesthesia can be used safely in patients with sickle cell trait undergoing first-time coronary artery bypass graft surgery. Extubation time and intensive care unit and hospital length of stay are comparable to those of matched controls, and blood loss and transfusion requirements are not increased. A hematocrit of 20% seems to be a safe transfusion trigger during cardiopulmonary bypass in these patients.     

One hundred consecutive hepatobiliary resections for biliary hilar malignancy: preoperative blood donation, blood loss, transfusion, and outcome

BACKGROUND: Many reports on blood loss and transfusion requirements during hepatectomy for metastatic liver cancer or hepatocellular carcinoma have been published; however, there are no reports on these issues in hepatectomy for biliary hilar malignancy. The aim of this study was to review our experience with blood loss and perioperative blood requirements in 100 consecutive hepatectomies for biliary hilar malignancy. METHODS: One hundred consecutive hepatectomies with en bloc resection of the caudate lobe and extrahepatic bile duct for hilar malignancies were performed, including 81 perihilar cholangiocarcinomas and 19 advanced gallbladder carcinomas involving the hepatic hilus. Fifty-eight hilar resections were combined with other organ and/or vascular resection. Data on preoperative blood donation, intraoperative blood loss, and perioperative transfusion were collected and analyzed. RESULTS: Preoperative autologous blood donation was possible in 73 patients (3.4 +/- 1.2 U). Intraoperative blood loss was 1850 +/- 1000 mL (range, 677-5900 mL), and it was < 2000 mL in 62 patients. Intraoperatively, only 7 of the 73 patients (10%) who donated blood received transfusion of unheated, homologous blood products (packed red blood cells or fresh frozen plasma), whereas 18 the 23 patients (67%) without donation received homologous transfusions. Only 16 patients received transfusion postoperatively, and overall, 35 patients received unheated homologous blood products. Total serum bilirubin concentrations after hepatectomy in patients receiving autologous blood transfusion only was similar to those in patients who did not receive transfusion. The incidence of postoperative complications was higher in the 35 patients who received perioperative homologous transfusion than in 65 patients who did not (94% vs 52%; P <.0001). The mortality rate (including all deaths) was 3% (myocardial infarction, intra-abdominal bleeding, and liver failure, 1 patient each). CONCLUSIONS: Despite the technical difficulties arising from hepatectomy for biliary hilar malignancy, approximately two thirds of hepatectomies can be performed in an experienced center without perioperative homologous blood transfusion using preoperative blood donation.     

Massivtransfusion mit dem Rapid Infusion System®Einfluss auf die Körperkerntemperatur

Extensive blood loss requires adequate volume replacement. However the infused volume cannot be adequately warmed especially when high infusion rates are necessary. Subsequently, hypothermia develops and results in hemodynamic instability and coagulopathy. The Rapid Infusion System (RIS) allows high infusion rates (up to 1.5 l/min) while at the same time guaranteeing sufficient warming. The efficacy of the RIS was investigated in 43 consecutive patients who required a massive transfusion. The average volume transfused in these patients was 31.7 +/- 4.5 l (minimum: 7.8 l; maximum: 165.3 l) which is equal to an average exchange of 6.4 times the circulating blood volume (maximum: 39.4 blood volumes). The replacement of such high blood volumes has not yet been published in a series of patients. Despite these high transfusion rates, the body core temperature was maintained at 35.85 +/- 0.1 degrees C. Only five patients had a body core temperature below 34 degrees C, all were trauma patients and four of these five patients already had a preoperative temperature below 34 degrees C. The mortality in this study was 28%, which is markedly reduced in comparison to previous publications although they all considered at patients with significantly less blood loss. Maintaining normothermia and normovolemia by the use of the RIS may explain the improved outcome.     

Rh(D)阴性血型病人剖宫产术中成分式自体输血的安全性

目的 评价Rh(D)阴性血型病人剖宫产术中成分式自体输血的安全性.方法 拟行剖宫产术的Rh(D)阴性血型病人30例,年龄20～35岁,体重50～80 kg,ASA分级Ⅰ或Ⅱ级.静脉输注乳酸钠林格氏液7 ml/kg后经桡动脉采血,采血速率60～80 ml/min,采血同时静脉输注与采血等速率的6%羟乙基淀粉130/0.4.采集的自体血经2个循环的直接法分离为富含血小板血浆、贫血小板血浆和浓缩红细胞,每个循环以分离出红细胞后15 s时停止采血.出血量≥全身血容量的20%时立即回输自体血;出血量<全身血容量20%者,在缝合子宫后回输,依次回输富含血小板血浆、输贫血小板血浆和输浓缩红细胞.监测母体生命体征指标和胎儿心率.记录自体血采集过程中低血压和心动过速的发生情况.分别于采血前(基础状态)、采血结束时、自体血回输前和术后24 h时采集外周静脉血样,测定Hb、Hct、Plt、PT、APTT、INR和Fib.胎儿娩出后采集脐动脉血样,进行血气分析.于胎儿娩出后1、5min时行Apgar评分.记录术中出血量和异体输血情况.结果 自体血采集过程中未见低血压和心动过速的发生,胎儿HR维持在正常范围.与基础状态比较,其他时点SpO2、Hb、Hct、Plt、PT、APTT、INR和Fib差异无统计学意义(P>0.05).脐动脉血pH值、BE和乳酸浓度均在正常范围内.胎儿娩出后1、5 min时Apgar评分分别为(9.0±0.8)、(9.2±0.8)分;术中出血量(405±28)ml,所有病人未输注异体血.结论 Rh(D)阴性血型病人剖宫产术中成分式自体输血的安全性良好.

Abstract：

Objective To investigate the safety of autologous blood component transfusion during cesarean section in patients with Rh (D)-negative blood group.Methods Thirty ASA Ⅰ or Ⅱ patients of Rh (D)-negative blood group, aged 20-35 yr, weighing 50-80 kg, undergoing elective cesarean section, were enrolled in this study.After lactated Ringer' s solution 7 ml/kg was infused, blood was obtained from radial artery at a rate of 60-80ml/min, and blood volume was maintained by simultaneous infusion of 6% hydroxyethyl starch 130/0.4 at the same rate. The collected blood was subjected to two cycles of autologous blood component separation. Blood collecting during each cycle was stopped 15 s after red blood cells were separated. The autologous blood was infused when the blood loss≥20% of blood volume. The autologous blood was infused after suture of the uterus when the blood loss < 20% of blood volume. The parameters of maternal vital signs and fetal heart rate were monitored. Hypotension and tachycardia were recorded during autologous blood collecting. SpO2 was monitored routinely. Venous blood samples were taken before blood collecting (baseline), at the end of blood collecting, before autologous blood transfusion, 24 h after operation for determination of Hb, Hct, Plt, PT, APTT, INR and Fib. Umbilical arterial blood samples were obtained after delivery for blood gas analysis. Apgar score was recorded at 1 and 5 min after birth. Blood loss and allogeneic blood transfusion were also recorded. Results No hypotension and tachycardia occurred during the process of blood collecting and the fetal heart rate was within the normal range. Compared with the baseline value, there were no significant differences in SpO2 , Hb, Hct, Plt, PT, APTT, INR and FIB value at the other time points. The pH value and concentrations of base excess and lactate were within the normal range.The Apgar score was (9.0 ±0.8) and (9.2 ± 0.8) at 1 and 5 min after birth respectively. The blood loss during operation was (405 ± 28) ml and no patients received homologous blood transfusion. Conclusion The safety of autologous blood component transfusion is good during cesarean section in Rh (D)-negative blood group patients.     

Transfusion for operation: reduction and proper preparation of blood for transfusion

In order to minimize preoperative transfusion requirements and to order proper preoperative transfusion blood, we induced deliberate hypotension and analyzed preoperative preparation of blood with C/T (cross-match/transfusion) ratio. We tried to establish a maximum surgical blood order schedule (MSBOS) based on the surgical transfusion experience of about 10 operations at our hospital. Deliberate hypotension was induced with prostaglandin E1 (PGE1) in 14 patients with mastectomy. Bleeding volume in PGE1 group (n = 7) was reduced to approximately 50% of control group (n = 7) at average dose of 35 +/- 25 ng.kg-1.min-1 with enough urine output. The dose of PGE1 was smaller than other reports because of the application of continuous epidural block to general anesthesia in all cases. Average C/T ratio was 4.6 and it was 3.6-24 in the 10 operations, which are higher than recommended value of the Ministry of Health and Welfare as well as ASA committee. We confirmed deliberate hypotension with PGE1 and continuous epidural block under general anesthesia were useful to minimize blood loss during mastectomy and clarified the improvement of the present preoperative blood ordering.     

A clinical study of the analysis and ranking of the determinant factors for non-blood open heart surgery]

We analyzed the determinant factors as to whether open heart surgery with non-blood transfusion may be indicated or not, according to the formula based on the quantitative theory (class II). Extracorporeal circulation with non-blood priming were indicated on 106 patients using Cell Saver apparatus in our department, they were divided into two groups; blood transfusion group (group I): 38 patients, and non-blood transfusion group (group II): 68 patients. These two groups were compared for study in terms of age, preoperative body weight (BW), the body surface area (BSA), preoperative Hct value (Hct), calculated Hct value (Hct(C)) at the start of extracorporeal circulation (ECC), the aortic cross-clamping time (AXT), the total extracorporeal circulation time (TECCT) and total bleeding amount. The followings are described in the ranking of importance. 1) The amount of blood loss in ICU: less than 400 ml. 2) Hct(C): more than 30%. 3) The amount of blood loss after ECC: less than 130 ml. 4) Hct: more than 40%. 5) BW: more than 55 kg. 6) The total bleeding amount: less than 600 ml. 7) TECCT: less than 90 min. 8) AXT: less than 50 min. In addition, prospective factors which should be considered preoperatively are determined in the following ranking. 1) Hct. 2) Hct(C). 3) BW. From these results, the amount of blood loss in ICU, Hct and Hct(C) were found to be reliable critical in any case as determinant factors for open heart surgery with non-blood transfusion.     

Effects of intraoperative plasmapheresis on blood loss in cardiac surgery

Intraoperative platelet-rich plasmapheresis allows autotransfusion of fresh, undamaged platelets and clotting factors at the completion of the operation. To evaluate this technology, we randomly assigned 100 consecutive patients who were to undergo an elective coronary bypass procedure and had normal clotting studies into the experimental (plasmapheresis) or the control group. Characteristics of both groups were similar, including average age (61.4 years versus 61.3 years [experimental versus control group]), sex (78% male versus 74% male), preoperative weight (80.9 kg versus 80.2 kg), preoperative red cell mass (1,989 mL versus 1,890 mL), perfusion time (102 minutes versus 106 minutes), and coagulation studies. Both internal mammary arteries were used in 68% of the patients. All patients had preoperative and postoperative blood volume determinations and complete clotting studies. Sixty-two variables related to bleeding were analyzed. Strict indications for transfusion were a hemoglobin level less than 7 g/100 mL in patients younger than 70 years and a hemoglobin level less than 8 g/100 mL in patients older than 70 years. The group receiving intraoperative plasmapheresis had a significant reduction in operative red cell mass loss (1,050 +/- 43 mL versus 1,226 +/- 61 mL; p = 0.021), a reduction in the average homologous transfusion (0.67 +/- 0.15 unit versus 1.8 +/- 0.25 units; p = 0.0002), and an increase in the percentage of patients not requiring blood transfusions (66% versus 32%; p = 0.001). This technique is useful in reducing postoperative blood loss and homologous transfusions.     

Blood loss and the need for transfusion in patients who undergo partial or radical nephrectomy for renal cell carcinoma

PURPOSE: We assessed blood loss and subsequent transfusion associated with nephrectomy performed for suspected renal cell carcinoma to establish guidelines for preoperative autologous blood donation and identify a subgroup of patients that may benefit from erythropoietin administration. MATERIALS AND METHODS: We retrospectively reviewed the charts of 211 patients who underwent partial (73%) or radical (23%) nephrectomy for presumed renal cell carcinoma at our institution between 1990 and 1999. Patients were divided into groups 1-44.5% treated with radical nephrectomy for localized disease, 2-21.3% radical nephrectomy for metastatic lesions invading the renal vasculature or inferior vena cava, 3-8% radical nephrectomy for metastatic disease with locally extensive lesions and 4-26.5% partial nephrectomy for localized lesions. Patient charts were evaluated for preoperative and postoperative hematocrit, estimated blood loss, transfusions received, surgical complications and underlying disease. RESULTS: Median estimated blood loss was 200, 400, 250 and 555 cc in groups 1 to 4, respectively. However, patients in groups 2 and 3 had a substantially greater range of blood loss than those in groups 1 and 4, respectively. The incidence of those with a blood loss of greater than 1 l. was 7%, 36%, 24% and 11% in groups 1, to 4, respectively. The incidence of those requiring transfusion was significantly lower in group 1 than in groups 2 to 4 (18% versus 44%, 24% and 30%, respectively, p <0.009). Mean transfusion requirement plus or minus standard deviation was significantly greater in groups 2 and 3 than in 1 and 4 (2.3 +/- 1.08, 5.5 +/- 4.4, 11.3 +/- 9.6 and 2.3 +/- 1.7 units, respectively, p <0.05). No significant difference was noted in the change in hematocrit as a result of surgery in the 4 groups (p >0.05). Similarly underlying disease and operative complications did not have a significant effect on blood loss or transfusion (p >0. 05). CONCLUSIONS: Radical or partial nephrectomy for localized renal cell carcinoma leads to consistent and well tolerated operative blood loss that rarely results in the need for substantial transfusion. In contrast, nephrectomy for advanced disease may cause a risk of greater blood loss and subsequent need for the transfusion of multiple units of blood. While preoperative autologous blood donation may have limited value in this regard due to the high cost and number of units needed, preoperative erythropoietin administration may be a viable option. Prospective randomized studies are currently planned.     

Autologous platelet sequestration in patients undergoing coronary artery bypass grafting

OBJECTIVES: Blood conservation remains an important issue for patients undergoing cardiac surgery with cardiopulmonary bypass. Platelet sequestration (PSQ) is an aggressive autologous blood conservation method, whose effectiveness is still debated. The main objective of the present study was to evaluate whether PSQ reduces postoperative blood transfusion requirements in patients undergoing coronary artery bypass grafting (CABG) and to determine if PSQ is a cost-effective blood conservation method. MATERIAL AND METHODS: All adult patients admitted for CABG entered the study. Exclusion criteria were: recent blood transfusion (<7 days), a platelet count of 150x10(3)/microl or less, hematocrit less than 35% and body weight 50 kg or less. The sequestration was aim 20% or more of the total platelet plasma volume. The sequestration protocol was three sequestration cycles performed just prior to surgery. The concentrated platelet portion was reinfused after weaning from the cardiopulmonary bypass. Hundred seven parameters/patients were recorded. Sixty patients entered the study; 30 in the PSQ group and 30 controls (CTR). RESULTS: Patient characteristics, operation data, preoperative hematology and coagulation parameters did not differ between the groups. In the PSQ group a mean of 433+/-34 ml concentrated platelet portion was collected. The mean platelet count in the concentrated platelet portion was 749+/-157x10(3)/microl, resulting in a platelet yield of 28+/-6% (2040%). The average total chest tube blood loss was 423 ml (PSQ) compared to 858 ml (CTR), p<0.001. A greater number of CTR patients required blood transfusion postoperatively (23) compared to PSQ (3), P<0.001, and fluid requirements were also significantly increased in the control group, P<0.001. No statistical differences in hematology and coagulation parameters between the groups were observed. The hospital mortality was low and the incidence of postoperative complications was few and without group differences. Post-extubation gas exchange was better in PSQ patients compared to CTR. CONCLUSIONS: A preoperative PSQ of a minimum 20% of the total platelet plasma volume resulted in significantly lower postoperative blood loss and fluid and blood transfusion requirements compared to controls. Post-extubation gas exchange was also better after PSQ. Only one patient did not tolerate the sequestration. No other adverse effects of the procedure were observed.     

A simple mathematical approach to calculate blood loss in radical prostatectomy

INTRODUCTION: The aim of this study was to apply a simple mathematical approach to calculate blood loss in 126 patients undergoing radical retropubic prostatectomy (RRP). MATERIALS AND METHODS: Perioperative red blood cell loss (RBCL) was estimated by adding the difference in circulating red blood cells from before to after surgery to the allogeneic red blood cells transfused in the same period. RESULTS: Mean preoperative hematocrit was 45 +/- 4% and mean perioperative RBCL was 574 +/- 297 ml, corresponding to a mean equivalent whole blood loss (WBL) of 1,479 +/- 831 ml. Twenty of 126 patients (15.9%) received 42 units of allogeneic packed red blood cells (PRBC), for a mean of 2.1 +/- 1.2 U/patient. The transfusion rate was higher in patients with a preoperative hematocrit of 40% or less (45 vs. 13%, p = 0.014). CONCLUSIONS: Anatomical RRP is still associated with appreciable operative blood loss. Owing to the high preoperative hematocrit values, the allogeneic blood transfusion rate is low and the transfusion requirement of the majority of patients is limited to about 2 units of PRBC. Preoperative autologous blood augmentation strategies may not be routinely needed for patients with a basal hematocrit of >40%.     

Gender is an essential determinant of blood transfusion in patients undergoing coronary artery bypass graft procedure

STUDY OBJECTIVE: To determine factors that account for gender difference in the need for blood transfusion in coronary artery bypass graft (CABG) patients. DESIGN: Retrospective study of consecutive patients. SETTING: Anesthesiology department of a teaching hospital. PATIENTS: 253 CABG patients (163 males and 90 females). INTERVENTIONS: Packed red blood cells (PRBCs), platelets, and fresh frozen plasma (FFP) were transfused depending on the need of each patient. MEASUREMENTS AND MAIN RESULTS: For each patient, we recorded the gender, age, weight, height, body surface area (BSA), and duration of surgery. Hematocrit (Hct) levels prior to surgery, end of surgery, and at discharge from the hospital were recorded. PRBC administration and use of FFP and platelets were noted. Differences between the data for female and male patients were evaluated using Student's t-test, Chi-square test, and regression analysis. Approximately 60% female and only 20% male patients received PRBCs intraoperatively, whereas 78% females and only 43% males received PRBCs during their entire hospital stay. On average, females received 1.20 units of PRBCs intraoperatively and 2.38 units during the entire hospital stay, while the males received 0.31 units and 1.36 units for similar periods. Gender differences in PRBC transfusion persisted even when females and males were compared within the same subgroups for age, weight, duration of surgery, and preoperative Hct. PRBC units given intraoperatively had a significant correlation with age and preoperative Hct in females, but they had a significant correlation with age, preoperative Hct, and duration of surgery in males. PRBCs given during the entire hospital stay, however, had significant correlation with age, preoperative Hct, and duration of surgery in both females and males. Multiple logistic regression analysis showed that the probability of a patient receiving or not receiving PRBC transfusion is significantly influenced by age, preoperative PRBC mass, duration of surgery, and gender. CONCLUSION: Gender is an independent essential determinant of blood transfusion in CABG patients, and it may interact with age, weight, preoperative Hct, duration of surgery, and other factors in determining the probability of transfusion.     

Effect of hematocrit on regional oxygen delivery and extraction in an adult respiratory distress syndrome animal model

BACKGROUND: The purpose of this prospective, randomized, controlled study was to investigate the effects of hematocrit (Hct) on regional oxygen delivery and extraction following induction of adult respiratory distress syndrome (ARDS) in an animal model. METHODS: Animals were instrumented to monitor central venous pressure (CVP), systemic mean arterial pressure (MAP), pulmonary artery occlusion pressure (PAOP), and cardiac output (CO) and to measure blood flow in the renal, hepatic, and superior mesenteric arteries and portal vein. ARDS was induced, positive end expiratory pressure (PEEP) applied and CO was maximized with volume loading and epinephrine infusion. Data were acquired at baseline (BL) and at Hct levels ranging from 25% to 50%. RESULTS: Systemic DO(2) increased steadily and significantly with increased Hct. Systemic O(2) extraction ratio (O(2)ER) decreased significantly with increasing Hct until a threshold value of 40%, after which further increases in Hct did not cause a statistically significant decrease in O(2)ER. Similarly, renal and hepatic DO(2) increased and O(2)ER decreased in a statistical significant manner with transfusions up to a Hct of 35%. In the splanchnic circulation blood transfusions did not cause any statistically significant increase in DO(2), and O(2)ER showed no decrease after an Hct of 35%. Systemic, renal, hepatic, and splanchnic VO(2) were not affected by changes in Hct. Blood viscosity decreased from a baseline value of 2.9+/-0.2 centipoise at a Hct of 38% to 2.3+/-0.1 centipoise at a Hct of 25% (P<0.05). Viscosity increased progressively with increasing hematocrits and reached the value of 4.2+/-0.2 centipoise at an Hct of 50% (P<0.05 versus Hct 30%, 35%, 40%, 45%). CONCLUSIONS: Based on the results of this non-supply-dependent animal model we conclude that a progressive increase in Hct up to 40% causes a corresponding increase in systemic DO(2) associated with a decrease in O(2)ER. However, there is no improvement in renal, hepatic, and splanchnic DO(2) and O(2)ER after a threshold Hct of 35%. All other factors being the same, an Hct greater than 35% may in fact cause a decrease in blood flow rate and change in blood flow characteristics as a consequence of increased blood kinematic viscosity, which may alter and compromise cellular oxygen transfer.