Expected Blood Loss Research Articles

Intraoperative blood management in joint replacement surgery.

Interest is growing in blood conservation and avoidance of transfusion in patients undergoing orthopedic surgery, especially in the field of joint replacement. Several methods have proven successful in reducing intraoperative blood loss, which can translate into lessened allogeneic and autologous transfusion requirements. Available techniques include acute normovolemic hemodilution, hypotensive anesthesia, intraoperative blood salvage, specialized cautery, topical hemostatic agents, and pharmacologic agents given in the perioperative period. The greatest potential benefit arises in operations with greater expected blood loss or in special situations such as in patients with religious issues, bilateral joint replacement, coagulation disorders, or significant preoperative anemia.

Preoperative Assessment

The preoperative evaluation of patients is an essential component of their subsequent successful management. Its importance is often underestimated and it can be time consuming. In addition to assessing the patient's physical health, the preoperative visit is the first contact between patient and anaesthetist so it is important for establishing the patient's confidence. The aims of assessment are summarized in Figure 1. The main objective is to avoid any unanticipated problems during the patient's subsequent management. Anticipation of potential difficulties allows a suitable plan to be made and avoids crisis management. In patients with challenging problems it is essential to involve senior anaesthetists and surgeons at an early stage and, if possible, to work at elective times. Specific demands imposed by the surgery must be considered, such as the expected blood loss or the risk of nausea and vomiting. The various anaesthetic and analgesic techniques can be discussed and the preoperative medication rationalized. Postoperative treatment in high dependency or intensive care units can be planned and elective cases deferred until such beds are available. In emergency surgery, the time for evaluation is limited, as is the opportunity to optimize the patient's medical condition or organize special investigations.

Reducing unnecessary cross-matching: a patient-specific blood ordering system is more accurate in predicting who will receive a blood transfusion than the maximum blood ordering system.

Most blood transfusions are given in the operating room. Adoption of the Maximum Surgical Blood Ordering Schedule in the 1970s reduced the amount of blood unnecessarily cross-matched, but the national cross-match-to-transfusion ratio remains at approximately two-to-one. We tested the ability of a patient-specific blood ordering system (PSBOS) to more accurately predict potential operative transfusion. All adult patients who had blood cross-matched before surgery (February through June 1999) for elective operative procedures at the University of Michigan Hospital were identified. Complex surgeries were excluded. Surgeons estimated the expected blood loss for their surgeries, and the expected postoperative hematocrit was calculated using the patient's blood volume, the surgeon-defined expected blood loss, and preoperative hematocrit. Lowest tolerated hematocrit was set at 21% except in patients with coronary artery disease or who were ASA physical status III or more (28%). Sensitivity, specificity, positive predictive value, and negative predictive value of the PSBOS were calculated. Our analysis included 178 cases in which blood was cross-matched before surgery, representing 69 different surgeries and 42 surgeons. Only 16% of patients received an intraoperative transfusion. Of the 156 patients that PSBOS predicted would not require an operating room transfusion, 139 were not transfused. Of the 21 patients PSBOS predicted would be transfused, 11 were. The sensitivity of the algorithm as tested was 41%, the specificity 93%, the positive predictive value was 55%, and the negative predictive value was 89%. We conclude that PSBOS, which includes patient and surgeon variables in transfusion prediction, is more accurate than the Maximum Surgical Blood Ordering Schedule, which uses only surgical procedure. Currently, many units of blood set aside for surgery are never required, resulting in extra work and expense for blood banks. A formula that included patient weight and hematocrit and typical surgery blood loss was used to predict who would require transfusions. We reduced the predicted number of patients who had blood set aside from 178 to 21.

Effects of blood volume restitution following a portal hypertensive–related bleeding in anesthetized cirrhotic rats

The aim of this study was to investigate the influence of different strategies of blood volume restitution in the outcome of portal hypertension–related bleeding in anesthetized cirrhotic rats. Gastrointestinal hemorrhage was induced by sectioning a first order branch of the ileocolic vein in 38 cirrhotic rats (common bile duct ligation and occlusion). The subsequent hypovolemic shock was treated with no transfusion (n = 17), moderate transfusion (50% of expected blood loss, 5 mL, n = 11), and total transfusion (100% of expected blood loss, 10 mL, n = 10). At the end of the blood transfusion period (minute 15), mean arterial pressure (MAP) partially recovered in rats receiving moderate transfusion or no transfusion but decreased in the 10-mL transfusion group (↓12 ± 43%, P < .05 vs. no transfusion and 5 mL transfusion). After transfusion, groups given no or 5 mL transfusion remained hemodynamically stable. However, rats receiving 10 mL transfusion continued to deteriorate with persistent bleeding and progressive fall in MAP (↓65 ± 12%; P < .05 vs. no transfusion and 5 mL transfusion). Collected blood loss was significantly greater in the 10-mL group (20.0 ± 1.5 g) than in groups given 5 mL (15.9 ± 2.8 g; P < .05) or no transfusion (13.2 ± 2.1 g; P < .05 vs. 10 mL and 5 mL transfusion). Survival in the no transfusion group was 47%. Rats given 5-mL transfusion had 64% survival. The worst survival was observed in the 10-mL transfusion group (0% survival; P < .05). We concluded that a transfusion policy aimed at completely replacing blood loss worsens the magnitude of bleeding and mortality from portal hypertensive-related bleeding in cirrhotic rats. On the contrary, moderate blood transfusion allowed hemodynamic stabilization and increased survival. (HEPATOLOGY 2001;33:821-825.)

Short-Term Crystalloid Fluid Resuscitation in Uncontrolled Intra-abdominal Bleeding in Swine

Fluid therapy in uncontrolled bleeding is controversial. In a previously used experimental animal model of aortic injury, the outcome often was impaired by re-bleeding that began at least 20 minutes after crystalloid fluid resuscitation was initiated. Therefore, it was hypothesized that re-bleeding might be avoided if volume loading is carried out for 20 minutes and then discontinued. Ten minutes after a 5 mm laceration was produced in the infra-renal aorta on eight anesthetized pigs, they received a 20-minute intravenous infusion of Ringer's solution in the ratio of 1:1 to the expected blood loss. Hemodynamics were studied for 120 minutes using arterial and pulmonary artery catheters and blood flow probes placed proximal and distal to the aortic lesion and around the left renal artery and portal vein. The bleeding stopped between three and four minutes after the onset of bleeding. The blood flow rate dropped to 38% (mean) of baseline in the splanchnic region, to 31% in the upper aorta, and to 13% in the kidney. The flow rates and the oxygen consumption increased transiently during fluid resuscitation, but never reached baseline levels. Re-bleeding amounted to about 15% of the initial bleeding and occurred in only three of the animals. Four of the pigs died of shock within 90 minutes (range 47-85 minutes) after the aortic injury. Short-term crystalloid fluid therapy in uncontrolled aortic hemorrhage transiently improved the hemodynamic status and the oxygen consumption following the initial bleeding. Furthermore, the infusion did not cause re-bleeding of more than 100 ml, which occurred in previously conducted experiments when the infusion was continued for more than 20 minutes.

The predictive power of baseline hemoglobin for transfusion risk in surgery patients.

Preoperative hemoglobin concentration may be an important predictor of transfusion risk in surgical procedures with significant expected blood loss. Contemporary studies investigating transfusion risk with regard to the relationship between perioperative administration of Epoetin alfa and baseline hemoglobin provide data to test this hypothesis. The predictive power of seven preoperative variables (hemoglobin concentration, age, erythropoietin level, ferritin concentration, serum iron, total iron-binding capacity, and predicted blood volume) on transfusion risk was examined via retrospective logistic regression analysis of 276 orthopedic surgical patients. In the two studies used to perform the regression analysis, patients were treated daily with either Epoetin alfa or placebo. Based on the retrospective analyses, a prospective study was conducted to validate the hypothesis. Of the seven variables evaluated, baseline hemoglobin concentration and predicted blood volume were significantly predictive of transfusion risk in both Epoetin alfa- and placebo-treated patients. Further, an inverse correlation between hemoglobin concentration and transfusion risk was demonstrated in placebo-treated patients. Placebo-treated patients with hemoglobin > 10 to < or = 13 g/dL had an approximately twofold greater risk of transfusion than patients with hemoglobin > 13 g/dL. In contrast to placebo treatment, Epoetin alfa significantly reduced transfusion risk in patients with hemoglobin > 10 to < or = 13 g/dL. Baseline hemoglobin concentration is an excellent predictor of transfusion risk in orthopedic surgical patients. As a result, hemoglobin testing should be considered a part of routine preoperative testing for orthopedic surgical patients.

The Bridgeport Hospital experience with autologous transfusion in orthopedic surgery.

The transfusion records of 341 orthopedic patients who donated blood preoperatively in the years 1992 and 1993 were audited to review the transfusion practices associated with the surgical procedures. The study sample underwent 182 total knee (TKA), 123 total hip (THA) arthroplasties, and 33 laminectomies with fusion (LAM) and 3 without. Data used were age, gender, predonation hemoglobin concentration (Hbd), initial (Hbi) and final (Hbf) hemoglobin concentration, surgical procedure, surgical blood order (SBO), and estimated blood loss (EBL). We analyzed for means and associations and differences between covariates. The means of EBL (mL), transfused units, donated units, Hbi, (g/dL), Hbd, and Hbf (g/dL) for the most common procedures were: TKA--272, 1.1, 2.1, 10.4, 13.9, and 10.1; THA--951, 2.3, 2.4, 9.4, 13.8, and 9.9; and LAM--589, 1.5, 2.2, 12.0, 14.6, and 11.2. Phlebotomies for procedures with minimal blood loss, as for total knee arthroplasties, result in wastage. Autodonation under such circumstances takes patients to an unnecessary low hemoglobin concentration prior to either retransfusing the blood taken or discarding part of it. The number of preoperative autologous units donated can be reduced if predonation hemoglobin concentration is > 15 g/dL and expected blood loss is not > 2 g.

Do Heparinase Thrombelastographs Predict Postoperative Bleeding?

Postoperative hemorrhage is a major cause of morbidity and mortality in patients who undergo cardiopulmonary bypass (CPB). The thrombelastograph (TEG) is a viscoelastic whole blood test that measures clot dynamics from clot formation through clot lysis. Previous studies have shown that post-bypass TEGs are accurate predictors of postoperative bleeding. TEGs from heparinized blood reversed with heparinase may be employed during CPB to evaluate coagulation. CPB heparinase TEGs may allow for earlier recognition of patients who may bleed after bypass. Earlier TEG analysis would allow targeting of specific therapies to begin before the patient bleeds excessively. Fifty-four heparinase TEGs during warming and fifty-four native TEGs post-protamine administration were collected. Parameters evaluated were R, K, alpha angle, MA, MA60, coagulation index, activated clotting time. hematocrit, prothrombin time, partial thromboplastin time, thrombin time, fibrinogen concentration, platelet count, blood loss during and after CPB, and blood and blood product administration. Coagulation indexes for CPB heparinase TEGs that were less than -2 or heparinase TEGs that were fibrinolytic were 87% accurate in predicting patients with excessive intraoperative blood loss, but were not predictive of blood product administration. The sensitivity was 12.5% and the specificity was I 00% in predicting excessive intraoperative bleeding. Post-protamine coagulation index inversely correlated with intraoperative red blood cell administration (r=-0.403, p&lt;0.05), but was not predictive. Patients with fibrinolytic TEGs required blood products to compensate for expected blood loss associated with the fibrinolytic state. Simultaneous routine coagulation tests did not correlate significantly with blood loss or blood product administration, nor were they predictive. The findings of this study suggest that the presence of fibrinolysis in either a heparinase TEG on bypass or a post-protamine TEG is the most important predictor of blood and blood product administration. But, since only 20% of the patients in the study exhibited fibrinolytic TEGs, a study that included a much larger sample of patients would need to be done to confirm this finding.

Estimated Blood Loss and Transfusion Rates Associated with Percutaneous Nephrolithotomy

We analyzed retrospectively 127 percutaneous nephrolithotomies performed on 96 patients between 1986 and 1989 to estimate the average total blood loss from the procedure. Blood transfusions and a postoperative decrease in hemoglobin level were combined to estimate total blood loss. The average blood loss for uncomplicated 1-stage single puncture percutaneous nephrolithotomy was 2.8gm./dl. hemoglobin. Factors potentially influencing blood loss were identified. Multiple punctures and/or renal pelvic perforation was associated with a 2-fold greater blood loss. Half of the expected blood loss occurred in patients with a preexisting nephrostomy tract. Calculus morphology, location, composition and length did not affect total blood loss, nor did the number of fragments or stone-containing calices. Other factors, such as puncture site, type of fascial dilation, hypertension, renal insufficiency, infection, previous open renal surgery or previous extracorporeal shock wave lithotripsy, also did not affect total estimated blood loss. During the study years the blood transfusion rate was 23% in all patients and 14% in those with a single puncture uncomplicated by renal pelvic perforation and without a mature nephrostomy tract. The only statistically significant risk factors influencing the likelihood of a blood transfusion were preoperative anemia and total blood loss. Although our current transfusion rate associated with percutaneous nephrolithotomy (4% in nonanemic patients from 1989 to 1992) is much lower, patients must be made aware of the likelihood of blood transfusion, and urologists should recognize the risk factors for blood loss and transfusion.

L'érythroaphérèse préopératoire permet-elle d'éviter la transfusion homologue ?

The risk of transfusion-related viral infections promotes techniques intended to reduce such a risk. Preoperative erythroapheresis is an autologous blood collection technique which minimizes the inconvenience of repeated predeposit autologous donations. Erythroapheresis has been performed in 451 patients, 24 to 72 hours before surgery using a discontinuous flow cell separator (PCS+Haemonetics). The mean collected red cells volume was 485 ml (250-900) and was replaced by hydroxy-ethyl-starch (ELOHES). Homologous blood transfusion was avoided in 431 patients (95,6%). This technique is indicated for surgery with an expected blood loss between 1000 and 1500 ml or when the patient cannot be included in a preoperative blood donation programme. Preoperative erythrocytapheresis is a simple and well tolerated procedure. To have recourse to apheresis techniques allows to increase the number of autologous transfused patients.

Hémodilution normovolémique préopératoire par érythrophérèse

Normovolaemic haemodilution was carried out by crythropheresis by the Blood Bank, 24 to 72 yours before surgery, using a plasmapheresis device. A special disposable haemodilution kit was used, with one plasma and three red cell collection bags and CPD as anticoagulant. Plasma was replaced by 4 % albumin. One to 4 red cell packs with 75 % haemoatocrit was obtained and stored for 10 days. This technique is indicated for surgery with an expected blood loss between 1,000 and 1,500 ml, or when the patient cannot be included in a preoperative blood donation programme. The contra-indications are the same as those of intentional normovolaemic haemodilution. This technique has been used in 101 patients due to undergo orthopaedic surgery. Compared with standard haemodilution bags, the advantages of this technique are the excellent asepsis of this product, its 10 days storage and high haematocrit, and the absence of anaesthetic drugs within the bags as well. This technique does not interfere with haemodynamic conditions during anaesthesia ; it saves time for both anaesthetists and surgeons. In the authors' experience, this technique has in part replaced the more usual technique.

Juvenile nasopharyngeal angiofibroma.

AbstractThis paper contains a review of the gross pathology and histopathology of juvenile nasopharyngeal angiofibroma and a review of the theories of origin of this tumor. The relative merits of hormone therapy, carotid arteriography, external and interstitial radiation therapy, cryosurgery, and various surgical approaches are discussed.A plan for the management of these tumors has been developed:1. Estrogen therapy is begun one month pre‐operatively, if it is to be used.2. The patient sees a prosthodontist so that he may have a temporary plastic plate made which will fit onto the teeth in such a manner that it will hold a transpalatal flap in place following surgery, without disturbing the suture line.3. Arteriography is scheduled only if there is evidence of intracranial extension or an extensive recurrence.4. Radon seeds, usually 10 in number and 1 me in size, are ordered for the day of surgery.5. Liquid nitrogen is made ready for use with a closed cryo‐probe system.6. The expected blood loss and the possible use of planned hypotensive anesthesia are discussed with the anesthesiologist. An adequate supply of blood is to be available in the operating room at the start of the resection of tumor.7. A plan is made for a transpalatal or transantral approach, or both, or occasionally for a lateral rhinotomy approach. Rarely has a transmandibular pterygoid approach been found necessary.The combined transpalatal‐transantral approach is described in detail. Two. cases are presented.