Packed red cells in acute blood loss: dilutional coagulopathy as a cause of surgical bleeding

Efficacy and safety of tranexamic acid in cervical spine surgery: a systematic review and meta-analysis

Background

Tranexamic acid (TXA) is an antifibrinolytic drug associated with reduced blood loss in a range of surgical specialties. This meta-analysis aimed to compare the efficacy and safety of TXA in cervical surgery, focusing on its effects on intraoperative blood loss and related outcomes.

Methods

We searched the PubMed, EMBASE, Medline, and Cochrane Library databases to identify all literature related to TXA used in cervical spinal surgery. Intraoperative blood loss, postoperative drainage volume, total blood loss, postoperative hematological variables, and complications were analyzed.

Results

Eight trials met the inclusion criteria. The pooled results showed that intraoperative blood loss, total blood loss, and postoperative drainage volume were significantly lower in the TXA group than in the control group. The hemoglobin and hematocrit on postoperative day 1 was significantly higher in the TXA group than in the control group. There was no significant difference in complications between the two groups.

Conclusion

The available evidence indicates that TXA effectively reduces blood loss in cervical spinal surgery while maintaining a favorable safety profile, without increasing associated risks.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42023459652.

Plasma and Platelet Transfusions Strategies in Neonates and Children Undergoing Cardiac Surgery With Cardiopulmonary Bypass or Neonates and Children Supported by Extracorporeal Membrane Oxygenation: From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding

OBJECTIVES

To present the recommendations and consensus statements with supporting literature for plasma and platelet transfusions in critically ill neonates and children undergoing cardiac surgery with cardiopulmonary bypass or supported by extracorporeal membrane oxygenation from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

DESIGN

Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children.

SETTING

Not applicable.

PATIENTS

Critically ill neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A panel of nine experts developed evidence-based and, when evidence was insufficient, expert-based statements for plasma and platelet transfusions in critically ill neonates and children following cardiopulmonary bypass or supported by extracorporeal membrane oxygenation. These statements were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding experts. A systematic review was conducted using MEDLINE, EMBASE, and Cochrane Library databases, from inception to December 2020. Consensus was obtained using the Research and Development/University of California, Los Angeles Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. We developed one good practice statement, two recommendations, and three expert consensus statements.

CONCLUSIONS

Whereas viscoelastic testing and transfusion algorithms may be considered, in general, evidence informing indications for plasma and platelet transfusions in neonatal and pediatric patients undergoing cardiac surgery with cardiopulmonary bypass or those requiring extracorporeal membrane oxygenation support is lacking.

Predictors for blood loss in pediatric patients younger than 10 years old undergoing primary posterior hemivertebra resection: a retrospective study

Background

Blood loss during hemivertebra resection may be substantial. Few studies have examined the risk factors of blood loss undergoing hemivertebra resection, especially those in patients under 10 years old.

Methods

Patients under 10 years old diagnosed with congenital scoliosis and hemivertebra were retrospectively included from January 2014 to October 2017. They all had primary posterior hemivertebra resection at Peking Union Medical College Hospital. Perioperative information was collected and multivariable linear logistic regression was performed to determine the independent risk factors of blood loss.

Results

One hundred three patients were included. The mean total blood loss was 346 + 178 ml. The percentage of total blood loss to the EBV was 27.0 + 13.3%. Multivariable linear logistic regression indicated that preoperative total Cobb angle (P = 0.046) and the number of fused levels (P < 0.001) were independent risk factors of total blood loss. Preoperative platelet count and preoperative coagulation function were not associated with blood loss in patients undergoing hemivertebra resection.

Conclusions

Preoperative total Cobb angle and the number of fused levels determined the blood loss for patients undergoing hemivertebra resection.

A Comparative Analysis of the Metabolic and Coagulative Profiles in Patients with Idiopathic Scoliosis, Congenital Scoliosis and Healthy Controls: A Case-Control Study

Study Design

Single-center, observational, case–control study.

Purpose

Comparison and analysis of the metabolic and coagulative profiles in patients with idiopathic scoliosis, patients with congenital scoliosis, and healthy controls.

Overview of Literature

Serum melatonin deficiency has been a controversial topic in the etiopathogenesis of scoliosis. Low bone mineral density, low vitamin D3 levels, and high parathyroid hormone levels are common metabolic abnormalities associated with scoliosis that may be responsible for its pathogenesis. In addition to metabolic defects, several studies have shown coagulation defects that either persist from the preoperative period or occur during surgery and usually lead to more than the expected amount of blood loss in patients undergoing deformity correction for scoliosis.

Methods

The study population (n=73) was classified into those having congenital scoliosis (n=31), those with idiopathic scoliosis (n=30), and healthy controls (n=12). After detailed clinicoradiological evaluation of all the subjects, 10-mL blood samples were collected, measured, and analyzed for various metabolic and coagulation parameters.

Results

The mean serum melatonin levels in patients with idiopathic scoliosis were significantly lower than those in the healthy controls. Although the mean serum melatonin level in the congenital group was also low, the difference was not statistically significant. Serum alkaline phosphatase and parathyroid hormone levels were higher in the scoliosis groups, whereas the vitamin D level was lower. No differences were observed in the coagulation profiles of the different groups.

Conclusions

Low serum melatonin levels associated with scoliosis can be a cause or an effect of scoliosis. Moreover, low bone mineral density, high bone turn over, and negative calcium balance appear to play an important role in the progression, if not the onset, of the deformity.

Moderate plasma dilution using artificial plasma expanders shifts the haemostatic balance to hypercoagulation

Artificial plasma expanders (PEs) are widely used in modern transfusion medicine. PEs do not contain components of the coagulation system, so their infusion in large volumes causes haemodilution and affects haemostasis. However, the existing information on this effect is contradictory. We studied the effect of the very process of plasma dilution on coagulation and tested the hypothesis that moderate dilution with a PE should accelerate clotting owing to a decrease in concentration of coagulation inhibitors. The standard clotting times, a thrombin generation test, and the spatial rate of clot growth (test of thrombodynamics) were used to assess donor plasma diluted in vitro with various PEs. The pH value and Ca⁺² concentration were maintained strictly constant in all samples. The effect of thrombin inhibitors on dilution-induced hypercoagulation was also examined. It was shown that coagulation was enhanced in plasma diluted up to 2.0-2.5-fold with any PE. This enhancement was due to the dilution of coagulation inhibitors in plasma. Their addition to plasma or PE could partially prevent the hypercoagulation shift.

Fibrinogen and base excess levels as predictive markers of the need for massive blood transfusion after blunt trauma

Background

Assessment blood consumption and trauma-associated severe hemorrhage scores are useful for predicting the need for massive transfusion (MT) in severe trauma patients. However, fibrinogen (Fbg) and base excess (BE) levels might also be useful indicators for the need for MT. We evaluated the accuracy of prediction for MT of the scoring system vs. Fbg and BE.

Methods

The subjects of this retrospective single center observational study were patients with injury severity score ≥16 trauma, divided into a non-MT group and an MT group. We compared variables, including the scoring system (comprising vital signs and focused assessment with sonography for trauma; FAST) and Fbg between the groups. We then performed a multiple logistic regression modeling and a receiver operating characteristic analysis to clarify which value was the most useful predictive indicator for MT.

Results

There were 114 patients in the non-MT group and 39 in the MT group. The level of Fbg and BE were independent predictors of MT. The area under the curve values for Fbg and BE were 0.765 and 0.845, respectively, and the optimal cutoff values of Fbg and BE were 211 mg/dL and −1.4, respectively.

Conclusions

Fbg and BE levels can be used as an independent predictor for MT.

Comparative analysis of activity of coagulation Factors V and VIII and level of fibrinogen in fresh frozen plasma and frozen plasma

Background:

The aim of this study was to analyse and compare the activity of factor V, VIII and fibrinogen level in fresh frozen plasma and frozen plasma frozen after 8 hrs but within 24 hours after phlebotomy.

Materials and Methods:

Fresh frozen plasma separated from whole blood within 8 hours was compared with plasma separated within 24 hours after phlebotomy in terms of coagulation factors V and VIII and level of fibrinogen by standard methods using semi automated coagulometer sysmex CA50.

Results:

Longer storage of whole blood before processing resulted in significant decrease (18.4%) in activity of factor VIII but the fall in activity of factor V (6.52%) or level of fibrinogen (1.81%) was not significant.

Discussion:

These data suggest that there is good retention of coagulation factors in both types of plasma. Although there is significant fall in activity of factor VIII, but it is an acute phase reactant and raised in most of the diseases so it is suggested that frozen plasma would be an acceptable product for most patients requiring fresh frozen plasma.

Effect of low dose tranexamic acid on intra-operative blood loss in neurosurgical patients

Background:

Blood loss is often a major complication in neurosurgery that requires transfusion of multiple units of blood. The purpose of this study was to assess the effect of tranexamic acid (TXA) on intraoperative blood loss and the need for blood transfusion in patients undergoing craniotomy for tumor excision.

Materials and Methods:

A total of 100 patients aged 18-60 years, with American Society of Anesthesiologists physical Status 1 and 2 scheduled to undergo elective craniotomy for tumor excision were enrolled. Patients received 10 mg/kg bolus about 20 min before skin incision followed by 1 mg/kg/h infusion of either TXA or saline. Hemodynamic variables, intravenous fluid transfused, amount of blood loss and blood given were measured every 2 h. Laboratory parameters such as serum electrolytes and fibrinogen values were measured every 3 h. On the 5^th postoperative day hemoglobin (POD Hb5), Hb estimation was done and the estimated blood loss (EBL) calculated. Patients were also monitored for any complications.

Results:

The Mean heart rate in TXA group was significantly lower compared with the saline group. Mean arterial pressure and fibrinogen levels were higher in TXA group. The mean total blood loss in the TXA group was less than in the saline group. Blood transfusion requirements were comparable in two groups. The EBL and POD5 Hb were comparable in two groups.

Conclusion:

Even though, there is a significant reduction in the total amount of blood loss in TXA group. However, there was no reduction in intraoperative transfusion requirement.

A calcium-containing electrolyte-balanced hydroxyethyl starch (HES) solution is associated with higher factor VIII activity than is a non-balanced HES solution, but does not affect von Willebrand factor function or thromboelastometric measurements--results of a model of in vitro haemodilution

BACKGROUND

Hydroxyethyl starch (HES) is known to impair blood coagulation. The impact of calcium-containing, balanced carrier solutions of HES on coagulation is controversial. We investigated the effects of increasing degrees of haemodilution with modern 6%, electrolyte-balanced HES vs non-balanced HES on coagulation in vitro, and compared the balanced HES to a balanced crystalloid solution for an internal control.

MATERIALS AND METHODS

Blood samples from ten healthy volunteers were diluted in vitro by 20%, 40% and 60% with either calcium-containing balanced 130/0.42 HES, non-balanced 130/0.4 HES or balanced crystalloid. In all samples, blood counts, prothrombin time ratio, activated partial thromboplastin time, ionized calcium, factor VIII activity, von Willebrand factor antigen, von Willebrand factor collagen binding activity, and von Willebrand factor activity were determined, and activated rotational thromboelastometry (EXTEM and FIBTEM assays) was performed.

RESULTS

Haemodilution impaired coagulation in a dilution-dependent manner as determined by both conventional laboratory assays and thromboelastometry. Ionized calcium increased with balanced HES (p≤0.004), but decreased with non-balanced HES (p≤0.004). Prothrombin time ratio (p≤0.002) and factor VIII levels (p=0.001) were better preserved with balanced HES than with non-balanced HES in dilutions ≥40%. Thromboelastometry showed no differences between values in blood diluted with the balanced or non-balanced HES.

DISCUSSION

In vitro, a balanced calcium-containing carrier solution of 6% HES 130/0.42 preserved coagulation better than did non-balanced HES 130/0.4 as quantified by conventional coagulation assays, but not in activated thromboelastometry. One explanation could be the increased ionized calcium levels after dilution with calcium-containing carrier solutions.

Early coagulopathy is an independent predictor of mortality in children after severe trauma

To determine whether early coagulopathy affects the mortality associated with severe civilian pediatric trauma, trauma patients younger than 18 years admitted to a pediatric intensive care unit from 2001 to 2010 were evaluated. Patients with burns, primary asphyxiation, preexisting bleeding diathesis, lack of coagulation studies, or transferred from other hospitals more than 24 h after injury were excluded. Age, sex, race, mechanism of injury, initial systolic blood pressure, Glasgow Coma Scale score, Injury Severity Score, prothrombin time, partial thromboplastin time, platelet count, and international normalized ratio were recorded. An arterial or venous blood gas was performed, if clinically indicated. Coagulopathy was defined as an international normalized ratio greater than 1.2. The primary outcome was in-hospital mortality. Secondary outcomes were lengths of intensive care unit and hospital stay. Eight hundred three patients were included in the study. Overall mortality was 13.4%. The incidence of age-adjusted hypotension was 5.4%. Early coagulopathy was observed in 37.9% of patients. High Injury Severity Score and/or hypotension were associated with early coagulopathy and higher mortality. Early coagulopathy was associated with a modest increase in mortality in pediatric trauma patients without traumatic brain injury (TBI). In contrast, the combination of TBI and early coagulopathy was associated with a fourfold increase in mortality in this patient population. Early coagulopathy is an independent predictor of mortality in civilian pediatric patients with severe trauma. The increase in mortality was particularly significant in patients with TBI either isolated or combined with other injuries, suggesting that a rapid correction of this coagulopathy could substantially decrease the mortality after TBI in pediatric trauma patients.

Factors affecting the postoperative mortality in the ruptured abdominal aortic aneurysm

Background

Although patients with a ruptured abdominal aortic aneurysm (RAAA) often reach the hospital alive, the perioperative mortality is still very high. We retrospectively reviewed thirty patients who underwent repair of RAAA to identify the factors affecting postoperative mortality in a single hospital.

Materials and Methods

Between September 2007 and May 2011, thirty patients with RAAA underwent emergent surgery (n=27) or endovascular aneurysm repair (n=3). Their medical records were retrospectively reviewed regarding three categories: 1) preoperative patient status: age, gender, vital signs, serum creatinine, blood urea nitrogen, hematocrit, and hemoglobin level: 2) aneurysmal status: size, type, and rupture status; and 3) operative factors: interval time to operating room, operative duration, and amount of perioperative transfusion.

Results

The 30-day postoperative mortality rate was 13.3% (4/30); later mortality was 3.3% (1/30). On multivariate analysis, the initial diastolic blood pressure (BP), interval time to operating room and amount of preoperative packed cell transfusion were statistically significantly linked with postoperative mortality (p<0.05).

Conclusion

In this study, preoperative diastolic BP, preoperative packed cell transfusion amount and interval time between arrival and entry to operating room were significantly associated with postoperative mortality. It is important to prevent hemorrhage as quickly as possible.

Patient Blood Management: A Patient-Orientated Approach to Blood Replacement with the Goal of Reducing Anemia, Blood Loss and the Need for Blood Transfusion in Elective Surgery

Patient Blood Management (PBM) describes an evidence-based, multidisciplinary therapeutic approach. Its focus is on the treatment of the individual patient and as such comprises transfusion therapy and pharmacotherapy. Furthermore, the applicability of PBM is not limited to the perioperative setting but is applicable also to other therapeutic measures and disciplines where significant blood loss is known to occur and where transfusion of blood products is part of the established treatment. PBM is fundamentally based on 3 pillars: (1) optimization of the (preoperative) erythrocyte volume, (2) reduction of diagnostic, therapeutic, or intraoperative blood loss, and (3) increasing individual tolerance towards anemia and accurate blood transfusion triggers. PBM primarily identifies patients at risk of transfusion and provides a management plan aimed at reducing or eliminating the risk of anemia and the need for allogeneic transfusion, thus reducing the inherent risks, inventory pressures, and the escalating costs associated with transfusion.

Risk and crisis management in intraoperative hemorrhage: Human factors in hemorrhagic critical events

Hemorrhage is the major cause of cardiac arrest developing in the operating room. Many human factors including surgical procedures, transfusion practices, blood supply, and anesthetic management are involved in the process that leads to hemorrhage developing into a critical situation. It is desirable for hospital transfusion committees to prepare hospital regulations on 'actions to be taken to manage critical hemorrhage', and practice the implementation of these regulations by simulated drills. If intraoperative hemorrhage seems to be critical, a state of emergency should immediately be declared to the operating room staff, the blood transfusion service staff, and blood bank staff in order to organize a systematic approach to the ongoing problem and keep all responsible staff working outside the operating room informed of events developing in the operating room. To rapidly deal with critical hemorrhage, not only cooperation between anesthesiologists and surgeons but also linkage of operating rooms with blood transfusion services and a blood bank are important. When time is short, cross-matching tests are omitted, and ABO-identical red blood cells are used. When supplies of ABO-identical red blood cells are not available, ABO-compatible, non-identical red blood cells are used. Because a systematic, not individual, approach is required to prevent and manage critical hemorrhage, whether a hospital can establish a procedure to deal with it or not depends on the overall capability of critical and crisis management of the hospital.

Changes in polymorphonuclear leukocyte elastase concentrations and hemolysis parameters in patients transfused with different blood preparations, and in the blood preparations themselves

PURPOSE

Massive blood transfusion induces hemolysis and increases polymorphonuclear leukocyte elastase (PMNE) concentration. The purpose of this study was to compare hemolysis and PMNE concentrations in massive blood transfusions with three different preparations.

METHODS

In an in vitro study, eight 2-day-old packs of concentrated red blood cells in mannitol, adenine, glucose, phosphate, and citrate solution (MAP-CRC); concentrated red blood cells in citrate, phosphate, and glucose solution (CPD-CRC); or whole blood in citrate, phosphate, and glucose solution (WB) were stored at 4 degrees C. Supernatant concentrations of total and free hemoglobin, total haptoglobin, and PMNE were measured. In an in vivo study, 24 surgical patients with expected bleeding exceeding 3000 ml were transfused with CPD-CRC or MAP-CRC with fresh frozen plasma, or with WB. Platelet count, prothrombin time, activated partial thromboplastin time, serum total and free hemoglobin, and total haptoglobin and plasma PMNE concentrations were measured.

RESULTS

In the in vitro study, total and free hemoglobin concentrations were significantly higher in CPD-CRC than in the other two preparations. Total haptoglobin concentration was highest in the order of WB > MAP-CRC > CPD-CRC. The PMNE concentration was significantly higher in WB than in the other two preparations. In the in vivo study, at 3000-ml transfusion, total and free hemoglobin concentrations were significantly lower and activated partial thromboplastin time was longer in the patients with MAP-CRC compared with values in the other two groups. The PMNE concentration was significantly higher in the order of the WB > CPD-CRC > MAP-CRC groups.

CONCLUSION

During the storage of MAP-CRC, CPD-CRC, and WB, CPD-CRC had the greatest hemolysis and WB had the highest concentration of PMNE. Patients who received massive blood transfusion of MAP-CRC had the least hemolysis and the lowest concentration of PMNE.

[Coagulopaty in associated with massive transfusion]

Massive hemorrhage is a formidable challenge for anesthesia care providers in the elective setting and poses even greater potential challenges in the trauma setting. In all this cases, the anesthesia care providers are faced with large-volume resuscitations that typically start with crystalloid and colloid and rapidly progress to blood and blood products. These large-volume replacement may cause coagulopathy, which can be difficult to manage in the setting of ongoing blood loss. Coagulopathy associated with massive transfusion is multifactorial event that results from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Treatment strategies include the maintenance of adequate tissue perfusion, the corection of anemia, and the use of hemostatic blood products.

Massive transfusion and coagulopathy: pathophysiology and implications for clinical management

PURPOSE

To review the pathophysiology of coagulopathy in massively transfused, adult and previously hemostatically competent patients in both elective surgical and trauma settings, and to recommend the most appropriate treatment strategies.

METHODS

Medline was searched for articles on "massive transfusion," "transfusion," "trauma," "surgery," "coagulopathy" and "hemostatic defects." A group of experts reviewed the findings.

PRINCIPAL FINDINGS

Coagulopathy will result from hemodilution, hypothermia, the use of fractionated blood products and disseminated intravascular coagulation. The clinical significance of the effects of hydroxyethyl starch solutions on hemostasis remains unclear. Maintaining a normal body temperature is a first-line, effective strategy to improve hemostasis during massive transfusion. Red cells play an important role in coagulation and hematocrits higher than 30% may be required to sustain hemostasis. In elective surgery patients, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. In trauma patients, tissue trauma, shock, tissue anoxia and hypothermia contribute to the development of disseminated intravascular coagulation and microvascular bleeding. The use of platelets and/or fresh frozen plasma should depend on clinical judgment as well as the results of coagulation testing and should be used mainly to treat a clinical coagulopathy.

CONCLUSIONS

Coagulopathy associated with massive transfusion remains an important clinical problem. It is an intricate, multifactorial and multicellular event. Treatment strategies include the maintenance of adequate tissue perfusion, the correction of hypothermia and anemia, and the use of hemostatic blood products to correct microvascular bleeding.

A trial of fresh autologous whole blood to treat dilutional coagulopathy following cardiopulmonary bypass in infants

BACKGROUND

Transfusion of fresh whole blood is superior to blood component therapy in correcting coagulopathies in children following cardiopulmonary bypass (CPB); however, a supply of fresh homologous whole blood is difficult to maintain. We hypothesized that transfusion of fresh autologous whole blood obtained prior to heparinization for CPB and infused following CPB would be associated with improved coagulation function when compared with standard therapy.

METHODS

A total of 32 infants 5-12 kg undergoing noncomplex open cardiac surgery were randomly assigned to either the treatment or control group. In the treatment group, 15 ml x kg(-1) of autologous whole blood was collected into a CPDA bag prior to heparinization while 15 ml x kg(-1) of 5% albumin was infused intravenously. After reversal of heparin, coagulation tests were drawn in both groups, and the autologous whole blood was infused over 20 min in the treatment group.

RESULTS

The treatment group had greater (P < 0.05) improvement in platelet count, prothrombin time, and fibrinogen than the control group.

CONCLUSIONS

We conclude that collection of fresh autologous whole blood prior to heparinization and reinfusion following CPB is associated with greater improvement of coagulation status after CPB in infants.

The coagulopathy of massive transfusion

Recently, the Groupe d'Intérêt en Hémostase Périopératoire reviewed the pathophysiology of coagulopathy in massively transfused, adult and previously haemostatically competent patients in both elective surgical and trauma settings. In this article, we focus on our main observations. First, in most cases, the onset and severity of coagulopathy associated with massive transfusion differs depending on whether haemorrhage occurs as a result of trauma or elective surgery. In trauma patients, tissue trauma is uncontrolled, the interval between haemorrhage and treatment can vary widely, hypovolemia, shock and hypothermia are frequent, and coagulopathy is often related to the development of disseminated intravascular coagulation. Monitoring of haemostasis occurs late, when coagulopathy is installed, and treatment can be very difficult. In elective surgery patients, the situation remains controlled and, in most cases, a decrease in fibrinogen concentration is observed initially while thrombocytopenia is a late occurrence. Monitoring of haemostasis is ongoing and treatment is usually much simpler. Second, blood products have changed over time and this has affected the management of the bleeding patient. Contrary to the recommendations of studies published at a time when whole blood was readily available, the first line of treatment (at least in elective surgery patients) ought to be with fresh-frozen plasma to correct decreased levels of coagulation factors. The role of recombinant activated factor VII to treat bleeding that cannot be controlled by conventional measures remains to be clarified. Coagulopathy associated with massive transfusion remains an important clinical problem. Treatment strategies must be adapted to the context and to the blood products available. Nevertheless, the level of evidence supporting specific treatment options is low and more studies are required to guide our management of massively transfused patients.

Recombinant coagulation factor VIIa--a novel haemostatic agent in scoliosis surgery?

Spinal fusion surgery in children and adolescents with idiopathic scoliosis is often associated with severe haemorrhage. Recombinant coagulation factor VIIa (rFVIIa) has previously been shown to be an effective haemostatic treatment for severe bleeding associated with a variety of coagulopathic and non-coagulopathic indications. The aim of this retrospective study was to assess the safety and haemostatic efficacy of rFVIIa in a series of 26 consecutive adolescent patients with scoliosis (22 females; mean age 16.6 years) undergoing correctional surgery. A second series of 26 consecutive patients (20 females; mean age 16.2 years) who received standard therapy during surgery, represented historical controls. Blood loss, transfusion requirements, duration of surgery, and peri-operative measurements of coagulation parameters were compared between the two groups. Intra-operative and combined intra-operative and post-operative blood losses were significantly smaller in the rFVIIa-treatment group than in the historical controls (P=0.003 and 0.032, respectively); rFVIIa-treated patients also demonstrated significantly reduced blood loss per vertebral segment fused (P=0.032) and per hour of surgery (P<0.001). Intra-operative requirements for packed red blood cells were also significantly lower in the treatment group (P=0.042). Patients in the treatment group demonstrated rapid and maintained reduction of prothrombin time and international normalised ratio; values among rFVIIa-treated patients remained significantly lower than those in the control group at all time points evaluated (P<0.001). There were no deaths and no adverse events. These results suggest that rFVIIa is a safe and effective haemostatic agent for use during spinal fusion surgery in adolescent patients with idiopathic scoliosis; however, further research and randomised, placebo-controlled trials are needed to confirm these findings.

Tranexamic acid for major spinal surgery

Patients who undergo major spinal surgery often require multiple blood transfusions. The antifibrinolytics are medications that can reduce blood-transfusion requirements in cardiac surgery and total knee arthroplasty. The present role of synthetic antifibrinolytics, especially tranexamic acid, in reducing peri-operative blood-transfusion requirements in spine surgery is still unclear. The majority of studies exploring the role of these drugs in spine surgery have limited patient enrollment and report mixed results. The goal of the present review is to discuss the pharmacology of tranexamic acid briefly. A brief synopsis of the studies using the synthetic antifibrinolytics for spine surgery is presented. Finally, the potential risks and the benefits of antifibrinolytics are discussed.

Coagulation management in trauma patients

Hemorrhage after traumatic injury results in coagulopathy which only worsens the situation. This coagulopathy is caused by depletion and dilution of clotting factors and platelets, increased fibrinolytic activity, hypothermia, metabolic changes and anemia. The effect of synthetic colloids in compensating the blood loss further aggravates the situation. Bedside coagulation monitoring permits relevant impairment of the coagulation system to be detected very early and the efficacy of the hemostatic therapy to be controlled directly. Administration of fresh frozen plasma, platelet concentrations, clotting factors and probably antifibrinolytic agents is essential in restoring the impaired coagulation system in trauma patients.

Preoperative values of molecular coagulation markers identify patients at low risk for intraoperative haemostatic disorders and excessive blood loss

Conventional laboratory investigations of haemostasis like prothrombin time and activated partial thromboplastin time are not useful in predicting and managing intra-operative bleeding complications. In order to establish a possible "perioperative reference range" for thrombin generation prothrombin fragment F1+2 (F1+2) and fibrin degradation (D-dimer) markers, we measured F1+2 and D-dimer concentrations before surgery (but after induction of anaesthesia), 30 minutes into surgery, 10 minutes after the event expected to induce the maximal activation of the haemostatic systems, 90 minutes after surgery and on postoperative days 1 and 2 in 226 consecutive patients. Samples were collected from arterial lines. Twenty patients developed a clinically defined, intraoperative disorder of haemostasis, 206 did not. Patients with an intraoperative disorder of haemostasis had significantly higher preoperative F1+2 and D-dimer concentrations. Preoperative values for F1+2 and D-dimer concentrations above the 75th percentile of patients without an intraoperative disorder of haemostasis indicated a 2.70 to 2.88 fold risk of developing an intraoperative disorder of haemostasis (odds ratios were 3.04, 3.12 and 3.29 for D-dimer, ELISA, F1+2, and D-dimer latex tests, respectively with 95% confidence intervals from 1.20 to 8.46) with negative predictive values of 94%, but positive predictive values of only 16% to 26%. These data suggest that preoperative determination of molecular markers might be helpful in identifying a group of patients at high risk for intraoperative disorder of haemostasis by exclusion of low risk patients. Validation of such an approach requires a prospective trial.

Reduction of inappropriate use of blood products by prospective monitoring of transfusion request forms

OBJECTIVE

To determine the effect of prospective monitoring on appropriateness of transfusions of red cells, platelets and fresh frozen plasma (FFP).

DESIGN

Prospective interventional study.

SETTING

Royal Melbourne Hospital (a tertiary teaching hospital), Melbourne, Victoria, March-May 1996.

INTERVENTION

The blood product request form was modified to incorporate indications for transfusion and clinical and laboratory data. Requests were monitored by blood bank laboratory staff for conformation with hospital transfusion guidelines; non-conforming requests were discussed with the requesting medical practitioner by the Haematology Registrar before blood products were issued. In case of disagreement, blood products were always issued.

SUBJECTS

200 consecutive transfusion episodes for each product (red cells, platelets and FFP).

OUTCOME MEASURES

Appropriateness of transfusion, assessed by a Consultant Haematologist according to hospital guidelines. Rates of inappropriate transfusion episodes after intervention were compared with rates in a previous study.

RESULTS

After intervention, rates of inappropriate transfusion episodes fell significantly (red cells, 16% to 3% [P = 0.004]; platelets, 13% to 2.5% [P = 0.02]; and FFP, 31% to 15% [P = 0.02]). Almost all inappropriate FFP transfusion episodes post-intervention were due to failure to demonstrate prolongation of prothrombin or activated partial thromboplastin times more than 1.5 times the control value.

CONCLUSION

Prospective monitoring of request forms can reduce rates of inappropriate transfusions. High rates of inappropriate FFP transfusions possibly reflect uncertainty about appropriate laboratory criteria for FFP transfusion. While results of large prospective randomised controlled clinical trials of FFP transfusions are awaited, currently laboratory criteria can be retained, but should be applied with flexibility.