Mechanics of avian fibrous periosteum: tensile and adhesion properties during growth

Aprotinin is a proteinase inhibitor that reduces blood loss in total hip arthroplasty when administered in large doses. Little is known about the capability of smaller doses of aprotinin in reducing blood loss and transfusion needs in this surgical setting. We reviewed the medical records of 372 patients who had undergone unilateral primary total hip arthroplasty under general anaesthesia during a 6-year period (1989 to 1994) at our institution. Successively, 193 patients had and 179 patients had not received aprotinin in a dose of 20,000 kallikrein inhibitor units per kilogram body weight intravenously before surgery. Neither the volume of red blood cells lost nor that of red blood cells transfused during hospitalization differed significantly between the patients who had and those who had not received aprotinin (520 +/- 406 vs. 549 +/- 394 mL and 463 +/- 379 vs. 475 +/- 367 mL; P = 0.49 and P = 0.76 respectively). These results suggest that small-dose aprotinin was not effective in reducing blood loss and transfusion needs in patients undergoing unilateral primary total hip replacement.     

Genetic therapy for transplant vascular sclerosis

Red blood cells are still transfused inappropriately in spite of recent media attention and public awareness about the risks of blood products. A prospective audit was conducted to determine the avoidable blood transfusion rates in the elective perioperative setting utilising the guidelines issued by the American College of Physicians (ACP). Of 82 consecutive adult patients who were admitted for major elective surgery over a 3-month period, 28 were transfused a total of 94 units of homologous SAG-M blood, of which 50 (53%) were inappropriate as recommended by the ACP guidelines. Violations of the guidelines were perioperative transfusion in bleeding patients who were haemodynamically stable (31%) and transfusion in asymptomatic, stable patients solely to attain a haemoglobin level above 10 g% (22%). There is a need for objective, easily adaptable and widely disseminated consensus guidelines to the indications for red blood cell transfusion.     

Red blood cell transfusions for total hip replacement in a regional hospital. A six-year analysis

To evaluate changes in the need for homologous blood and to assess the impact of autologous blood transfusion, red cell transfusions in unilateral total hip replacement surgery, performed electively in the period 1986-1991, were studied in a regional hospital. Transfusion data, perioperative blood loss and post-operative haemoglobin concentration of 495 patients were analysed. From 1986 to 1991, the percentage of patients not transfused with homologous blood increased from 18.5 to 45.5%. After the introduction of an autologous blood transfusion programme in 1987, 116 of 430 patients (27.0%) donated autologous blood. No increase in the percentage of autologous donors was observed during the study. Most common reasons for nonparticipation were the patient's age, doctors' underordering and logistic limitations. 81.9% of autologous donors had total hip replacement surgery without homologous transfusions. Mean blood loss reduced significantly from 1,373 +/- 781 ml in 1986 to 958 +/- 582 ml in 1991 (p < 0.001). Transfusion requirement in the nonautologous patients fell from 2.6 +/- 1.8 units in 1986 to 1.4 +/- 1.4 units per patient in 1989 and increased thereafter to 2.2 +/- 2.1 units in 1991 (p < 0.01) and showed a strong correlation with blood loss (r = 0.58; p < 0.001). No changes in postoperative haemoglobin concentration were observed throughout the study. In conclusion, collection of autologous blood is effective, albeit still underutilized, to reduce homologous blood requirement. The close correlation between blood loss and transfusion requirement accentuates the role of surgical practice in the reduction of homologous transfusions.     

Intraoperative autotransfusion is associated with modest reduction of allogeneic transfusion in prosthetic hip surgery

BACKGROUND: The efficacy of intraoperative salvage and washing of wound blood and the predictors of allogeneic red cell transfusions in prosthetic hip surgery are insufficiently known. METHODS: In 96 patients, undergoing primary or revision surgery, salvaged and washed red cells and, if necessary, allogeneic blood were used to keep haematocrit not lower than 33%. The bleeding of red cells during hospital stay was calculated from the red cell balance. The preoperative red cell reserve (mililitres of red cells in excess of a haematocrit of 33%) was estimated and the difference between this volume and the total bleeding of red cells was retrospectively used to classify patients with regard to the need for red cells. Stepwise regression analysis was used to define patient-related variables associated with allogeneic blood transfusion. RESULTS: Preoperative knowledge of the type of operation (primary, revision), the preoperative red cell reserve, and the body mass could predict roughly half of the need for banked blood (r2 = 0.45). Only one-third of the total bleeding of red cells was retransfused. For complete avoidance of allogeneic blood, autotransfusion was most effective in patients with a moderate need (0-4 u). However, 32% of such patients required allogeneic blood. CONCLUSIONS: Autotransfusion has a limited efficacy to decrease the need for allogeneic blood, and other blood-saving methods should be added for this purpose. It is difficult to predict the need for allogeneic blood preoperatively.     

The risk of acquiring Lyme disease or babesiosis from a blood transfusion

To determine the risk of acquiring Lyme disease or babesiosis from blood transfusion, serum was collected before and 6 weeks after patients received multiple transfusions during cardiothoracic surgery and antibodies to Borrelia burgdorferi and Babesia microti were measured. Of 155 subjects, 149 received 601 total units of packed red blood cells (PRBC) and 48 received 371 total units of platelets. No patient developed clinical or serologic evidence of Lyme disease; 1 (who received 5 units of PRBC) developed clinical and serologic evidence of babesiosis. The risk of acquiring Lyme disease from a transfused unit of PRBC was 0 (95% confidence interval [CI], 0-0.5%) and from a transfused unit of platelets was 0 (95% CI, 0-0.8%); the same risks for babesiosis were 0.17% (95% CI, 0.004%-0.9%) and 0 (95% CI, 0-0.8%), respectively. The risk of acquiring either Lyme disease or babesiosis from a blood transfusion in Connecticut is very low.     

Changing transfusion practices in hip and knee arthroplasty

BACKGROUND: This study was designed to examine changes in perioperative transfusion practices after the introduction of autologous blood conservation strategies into routine clinical practice. STUDY DESIGN AND METHODS: The existing medical records of all patients undergoing total hip or knee arthroplasty at Mayo Clinic in Rochester, MN, who resided in Olmsted County, were reviewed over three periods: 1981-82 (232 procedures), 1987-88 (269 procedures), and 1993-94 (398 procedures). RESULTS: The proportion of patients receiving any perioperative red cell (RBC) units significantly decreased (from 85% in 1981-82 to 65% in 1993-94). The timing of transfusion also changed; the proportion of RBC units transfused in the preoperative or intraoperative periods decreased from 68 percent in 1981-82 to 38 percent in 1993-94, with the balance of RBC units transfused in the postoperative period. Although the number of RBC units utilized per procedure in the intraoperative period significantly decreased, the number of RBC units transfused in the postoperative period significantly increased (from 0.6 +/- 1.0 to 1.1 +/- 1.4 units per procedure in 1981-82 and 1993-94, respectively, p < 0.05). CONCLUSION: Although blood conservation strategies have been successful in reducing RBC transfusion intraoperatively, avoidance of intraoperative transfusion may in some cases postpone, rather than prevent, transfusion.     

Lack of adherence to the guidelines on the use of fresh frozen plasma

OBJECTIVE: Evaluation of transfusion practice with regard to the guidelines for fresh frozen plasma. DESIGN: Prospective. SETTING: Academic Medical Centre, department of internal medicine, Amsterdam, the Netherlands. METHOD: During 4 weeks in April-May 1996 the indication of every request for fresh frozen plasma was established by an inquiry by telephone and compared with the indications defined by the National organization for quality assurance in hospitals (CBO). To objectivate the stated indication it was checked whether laboratory tests had been performed (prothrombin time (PTT) and activated partial thromboplastin time (APTT), and if so, what the results were. Moreover, the numbers of transfused units of red cells, platelets and fresh frozen plasma in the first 24 hours were checked. RESULTS: During the study period there were 195 requests for 844 units of plasma. 613 units were transfused in 100 patients. If the CBO guidelines were applied strictly, the proportions of plasma units inappropriately requested and inappropriately administered were 53% and 47% respectively (in 32 patients). If the CBO indications were applied less strictly, still 25% of the units were inappropriately requested and 18% inappropriately administered (in 23 patients). CONCLUSION: The guidelines were observed only moderately. Better compliance is important for medical, logistic and financial reasons.     

Perioperative specific management of blood volume loss in craniosynostosis surgery

Accurate assessment and replacement of blood loss and fluid-electrolyte deficit during craniosynostosis repair is difficult owing to patient size and the diversity of surgical technique. Forty-three patients undergoing primary craniosynostosis repair over a 10-year period were studied retrospectively to determine blood loss and fluid deficit and to assess blood transfusion practices during both intraoperative and postoperative periods. Blood loss was calculated on the basis of estimated red cell mass (ERCM) and fluid-electrolyte imbalance was investigated with blood samplings. Blood transfusion was considered appropriate if the postoperative or posttransfusion ERCM was within 12% of the preoperative value. Estimated fluid requirement (EFR) was used in 4 ml kg(-1) h(-1) except for neonates. Intraoperatively, 80% of all patients were appropriately managed with respect to blood transfusion and EFR. Postoperatively only 20% of the patients receiving transfusions were transfused appropriately. In 23.3% of these patients (10/43) unexpected respiratory distress developed immediately after their recovery from the anesthesia. With the measurement of estimated blood volume and allowable blood loss, appropriate transfusion could be achieved for the successful treatment of the primary craniosynostosis.     

Giving both enoxaparin and dextran increases the need for transfusion in revision hip arthroplasty

OBJECTIVE: To find out if the need for transfusion was increased by volume substitution with dextran 70 in patients receiving prophylaxis against thrombosis with low molecular weight heparin. DESIGN: Open randomised controlled trial. SETTING: University hospital, Sweden. SUBJECTS: 40 patients undergoing revision hip arthroplasty. INTERVENTIONS: Enoxaparin 40 mg was given daily. Intraoperative normovolaemia was maintained with albumin (n = 20) or dextran 70 (n = 20). Intraoperative autotransfusion was used. Packed cell volume was kept above 0.29, if necessary with homologous blood. MAIN OUTCOME MEASURES: External blood loss, red cell balance. RESULTS: Dextran patients received 0.64 (0.2) g/kg of dextran (mean (SD)) and required more (p < 0.05) homologous blood (3.8 (2.4) units) than those receiving albumin (2.3 (1.6) units). The initial and final packed cell volumes were similar (0.40 and 0.32 compared with 0.41 and 0.32, respectively). The calculated loss of red cells was larger in the dextran group (1401 (511) compared with 1077 (374); p < 0.05). CONCLUSION: The combination of enoxaparin and dextran appreciably increased the need for transfusion compared with enoxaparin alone.     

Blood conservation in hip trauma

Patients with hip or pelvic fractures experience significant blood loss as a result of the fracture and from the surgery that subsequently is performed. The emergent and unplanned nature of fracture surgery precludes the use of preoperative blood donation and the optimization of chronic medical problems. Blood transfusion frequently is required to maintain adequate tissue O2 delivery in these injured patients. However, the administration of allogeneic blood causes other problems, including a well documented increase in the risk of infectious complications. Perioperative measures to minimize blood loss such as hypotensive anesthesia and red blood cell salvage are important, but often are inadequate to prevent the need for blood transfusion. Recently, erythropoietin therapy has been shown to stimulate hematopoiesis in patients with hip fractures. The authors discuss their experience with blood loss management in these patients with hip injuries, including aggressive Fe replacement therapy and the use of recombinant human erythropoietin.     

Blood utilization in hip and knee arthroplasty: a cost-minimization study

The non-utilization of crossmatched blood is an expensive waste of resources. We have audited blood utilization for all primary total hip and knee arthroplasty patients. We compared routine pre-operative crossmatching (Phase 1) with a policy of group, screen and save (G & S) only (Phase 2). The patient groups were similar in both phases. Pre- and post-operative haemoglobin results were not significantly different between Phase 1 and 2. No adverse transfusion reactions occurred. In Phase 1, 213 units were crossmatched pre-operatively, but only 127 (60%) were transfused. In Phase 2, 117 units were requested and all transfused. The G & S only policy proved to be a safe and practical option which improved the efficiency and cost-effectiveness of blood ordering. Based on a handling charge of 37.50 Pounds per unit of blood by the Regional Transfusion Centre, an estimated annual saving of over 8000 Pounds can be made in our directorate.     

Recombinant human erythropoietin as adjuvant treatment for autologous blood donation in elective surgery with large blood needs (> or = 5 units): a randomized study

BACKGROUND: Autologous blood transfusion presents no infectious or immunologic side effects. The aim of this randomized study was to determine the impact of recombinant human erythropoietin (rHuEPO) on the donation of 5 units of autologous blood by nonanemic patients who were candidates for elective surgery with transfusion requirements of > or = 5 units. STUDY DESIGN AND METHODS: Starting on Day -35, 420 mL of blood was taken weekly. All patients received 200 mg of iron saccharose complex intravenously at each visit and six subcutaneous injections of rHuEPO (141 U/kg) or placebo between Days -21 and -7. RESULTS: Of 50 patients, 45 completed the study (placebo, 21; rHuEPO, 24). Total red cell production was higher in the rHuEPO group (p = 0.001). Donation of 5 units was possible for 67 percent (placebo group) and 79 percent (rHuEPO group) of patients (p = 0.5). The mean number of blood units donated was 4.6 (placebo group) and 4.7 (rHuEPO group). More patients in the placebo group received allogeneic blood (9/21 [43%] vs. 6/23 [26%]), although the difference did not reach significance (p = 0.34). CONCLUSION: In nonanemic patients donating 5 units of blood, rHuEPO associated with intravenous iron increased total red cell production. However, no difference was found between the rHuEPO and placebo groups with regard to the number of units of autologous blood donated of the number of patients receiving allogeneic blood transfusion.     

Prospective randomized placebo-controlled trial of aprotinin for elective aortic reconstruction

BACKGROUND: The serine protease antagonist, aprotinin, reduces perioperative blood loss in cardiac surgery and orthotopic liver transplantation. A pilot study suggested that the drug may also reduce bleeding during infrarenal aortic replacement; the aim was to confirm or refute this observation with a prospective, randomized, double-blind, placebo-controlled trial. METHODS: Some 136 patients were randomized to receive either aprotinin, given as a loading dose of 2 x 10(6) kallikrein inactivator (KI) units followed by 0.5 x 10(6) KI units/h or equal volumes of 0.9 per cent saline. After 80 patients had been randomized the infusion dose was doubled to ensure that plasma levels were similar to those seen in successful cardiac studies. Blood loss, coagulation and haematological parameters were recorded throughout surgery and for 7 days afterwards. Blood was transfused to maintain the haemoglobin level at 100 g/l. RESULTS: Four patients were withdrawn after randomization when found at laparotomy to be unsuitable for the planned reconstruction. The 30-day mortality rate was 4.5 per cent, with no excess complications in either group. Blood loss collected on swabs was reduced from 480 ml in placebo-treated patients to 379 ml with aprotinin (P = 0.014). Blood loss into suction drains in the first 24 h after operation was reduced from 295 to 205 ml in aprotinin-treated patients (P = 0.002). However, no significant reduction was found in intraoperative or total blood loss, or transfusion requirement. CONCLUSION: The small reduction in blood loss in patients treated with aprotinin demonstrated in this study does not support its use in routine elective aortic surgery.     

The specific hospital significantly affects red cell and component transfusion practice in coronary artery bypass graft surgery: a study of five hospitals

BACKGROUND: Interhospital differences in blood transfusion practice during coronary artery bypass graft (CABG) surgery have been noted, but the underlying issues have not been identified. STUDY DESIGN AND METHODS: Records of 3217 consecutive CABG cases in five university teaching hospitals in 1992 and 1993 were stratified by hospital, type of revascularization conduit, patients' sex, and other factors. Statistical methods were used to compare patient characteristics, transfusion outcomes, and hospital outcomes. RESULTS: Forward two-step logistic regression using patient likelihood of red cell transfusion factors in the first step and the specific hospital in the second step revealed a significant effect of hospital on the delta odds ratios for red cell transfusion. This finding was confirmed by analyses of a highly stratified subset of cases, males in diagnosis-related group 107 (primary cases of coronary bypass without coronary catheterization) who underwent revascularization with venous and internal mammary artery grafts, revealing variations among hospitals from 109 to 457 units of red cells transfused per hundred cases. Corresponding variations in transfusions of all blood components were from 324 to 1019 units by hospital. Variation in red cell transfusion practice among surgeons in the same hospital was not responsible for these interhospital differences. CONCLUSION: The effect of the specific hospital on transfusion practice is attributed to institutional differences that, through reasons of training or hierarchy, become ingrained in hospitals.     

Frontal sinus mucoceles causing proptosis--two case reports

BACKGROUND: Blood requirements for Head and Neck surgical procedures have not been studied carefully. In order to set up an autotransfusion program, the blood loss and transfusion requirements should be known precisely. METHODS: The blood bank database was used to determine which Head and Neck procedures required blood transfusion during the previous 5 years. A list of 10 transfusion-associated operations was established, the records of all patients who underwent these procedures during a 5-year period were reviewed, and average the blood loss and number of units transfused determined. RESULTS: All procedures were for cancer resection. The operations were classified in 3 groups according to their transfusion probability: high (> 80%), low (< 5%) and moderate. For the moderate transfusion group, age, preoperative hemoglobin, and past medical history of cardiac and pulmonary disease were associated with higher incidence of transfusion. An average delay of 3 weeks was found between the diagnosis and the actual surgery. CONCLUSION: The transfusion requirements of Head and Neck surgical procedures could be safely met by an autotransfusion protocol, given the average delay of 3 weeks between diagnosis and surgery.     

Blood transfusion and lung function in chronically anemic patients with severe chronic obstructive pulmonary disease

OBJECTIVE: To study in anemic patients with chronic obstructive pulmonary disease (COPD) whether blood transfusion reduces minute ventilation and work of breathing (WOB). DESIGN: We prospectively evaluated the minute ventilation and WOB in 20 anemic adults (hemoglobin of <11 g/dL). Ten patients had severe COPD and ten patients were without lung disease. Measurements were made before and after receiving red blood cell transfusion; post-transfusion measurements were made 24 to 36 hrs after the last transfusion. SETTING: The study was performed in the intensive care unit of a tertiary referral center for home mechanical ventilation and for patients considered difficult to wean from mechanical ventilation. PATIENTS: Twenty clinically stable patients (12 female, eight male) with chronic anemia were studied. Ten patients with COPD (mean forced expiratory volume in 1 sec: 0.55+/-0.1 [SD] L) were compared with ten patients without lung disease. All participants had adequate renal and left ventricular function. INTERVENTIONS: Patients received 1 unit of packed red blood cells for each g/dL that their hemoglobin value was less than an arbitrarily defined target value of 11.0 to 12.0 g/dL. Each unit was transfused over 2 hrs and < or =3 units in total was given. MEASUREMENTS AND MAIN RESULTS: Esophageal pressure was measured from a catheter which was positioned in the middle of the esophagus. Flow was measured using a pneumotachygraph connected to a mouthpiece while a nose clip closed the nostrils during the measurements. From these data, respiratory rate, minute ventilation, and inspiratory resistive WOB were computed. Arterial blood gas values, oxygen saturation, hemoglobin, and hematocrit were also measured, and oxygen content was calculated before and 24 to 36 hrs after transfusion. In patients with COPD, hemoglobin increased from 9.8+/-0.8 to 12.3+/-1.1 g/dL due to a mean transfusion of 2.2+/-0.4 (SD) units of red blood cells. There was a reduction in the mean minute ventilation from 9.9+/-1.0 to 8.2+/-1.2 L/min (p < .0001); correspondingly, WOB decreased from 1.03+/-0.24 to 0.85+/-0.21 WOB/L (p< .0001). The capillary P(CO2) increased from 38.1+/-6.0 to 40.7+/-6.8 torr (5.1+/-0.8 to 5.8+/-0.9 kPa) (p < .05). Similarly, capillary P(O2) changed from 56.9+/-8.9 to 52.8+/-7.0 torr (7.6+/-1.2 to 7.0+/-0.9 kPa) (p < .05). In anemic patients without lung disease, minute ventilation, WOB, and the capillary blood gas values did not change after increase of the hemoglobin by a similar degree. CONCLUSIONS: We conclude that red blood cell transfusion in anemic patients with COPD leads to a significant reduction of both the minute ventilation and the WOB. In these patients, transfusion may be associated with unloading of the respiratory muscles, but it may also result in mild hypoventilation.     

Efficacy of 2 different leukocyte filters for erythrocyte concentrates

By leukocyte reduction in red blood cell concentrates to < 5 x 10(6) leukocytes per transfused unit, febrile non-hemolytic transfusion reaction as well as alloimmunization and transmission of certain viral diseases (CMV, HTLV-1) can be prevented. Using a Nageotte hemocytometer with a large-volume chamber, the residual leukocyte number after filtration of 40 buffy-coat free red blood cell units with the filters Pall RC100 and Sepacell R500 B1 was determined in a clinical routine setting. Both tested filters underscored the limit (< 5 x 10(6) leukocytes per unit) set by the American Association of Blood Banks. Hemoglobin loss accounted for 8.9 g (Pall RC100) versus 7.7 g (Sepacell R500 B1), which is about 15-18% of the hemoglobin content of a red blood cell concentrate.     

Red blood cell transfusion practices in patients undergoing orthopedic surgery: a multi-institutional analysis

This retrospective review analyzed and compared transfusion practices in patients undergoing orthopedic surgery in five Massachusetts hospitals with current practice guidelines; opportunities for improvement were identified. Patient-specific clinical information and data about transfusion practices were obtained from the medical records of 384 Medicare patients undergoing orthopedic surgery between January 1992 and December 1993. The number of patients who donated autologous blood preoperatively differed significantly among hospitals as did the number of autologous units that were unused. The number of blood units transfused at each transfusion event also differed significantly; some surgeons transfused > or =2 units in the majority of their patients, while others transfused 1 unit at a time. This variation in practice was not explained by differences in patients' clinical status. The mean pretransfusion hematocrit was higher for autologous versus allogeneic blood, suggesting more liberal criteria to transfuse autologous blood. Nearly half of all transfusion events were determined to have been potentially avoidable. Avoidable transfusions were also three to seven times more likely with autologous than with allogeneic blood. Significant inter-hospital differences existed in the number of elective surgery patients exposed to allogeneic blood. The major determinant of allogeneic blood use in these patients was the availability of autologous blood. Each additional autologous blood unit available decreased the odds of allogeneic blood exposure twofold. Differences in intraoperative and postoperative blood salvage use also were noted. These findings indicate that significant variations in practice exist. Comparative data enabled hospitals to identify and target specific areas for improvement.     

Intraoperative heparinisation, blood loss and myocardial infarction during aortic aneurysm surgery: a Joint Vascular Research Group study

OBJECTIVES: The primary aim of this prospective multi-centre study involving patients undergoing elective abdominal aortic aneurysm (AAA) surgery was to investigate the relationship between intraoperative intravenous heparinisation, blood loss during surgery and thrombotic complications. METHODS: Two hundred and eighty-four patients were randomised to receive intravenous heparin (n = 145) or no heparin (n = 139). Groups were evenly matched for age, sex, weight, aneurysm size, haemoglobin concentration, platelet counts and distal occlusive disease measured by ankle/brachial systolic pressure. RESULTS: There were no statistically significant differences in blood loss (median 1400 ml vs. 1500 ml; z = 0.02, p = 0.98, 95% C.I. = -200 to 200), blood transfused (4.0 units vs. 4.0 units; z = 1.09, p = 0.28, 95% C.I. = -1 to 0) or distal thrombosis between the two groups. However, analysis of the clinical outcome revealed that 5.7% of the non-heparin group but only 1.4% of the heparinised patients suffered a fatal perioperative myocardial infarction (MI); p < 0.05. All MI, including non fatal events, affected 8.5% and 2% respectively (p = 0.02). CONCLUSIONS: Heparin does not increase blood loss or the need for blood transfusion during surgery. Heparin is not necessary to prevent distal thrombosis when the aorta is cross clamped. The results of the study are consistent with the known mechanisms leading to intraoperative MI and strategies for its prevention. Intravenous heparin, given before aortic cross clamping, is an important prophylaxic against perioperative MI in relation to AAA surgery.