Population Pharmacokinetics of Tranexamic Acid in Paediatric Patients Undergoing Craniosynostosis Surgery

Feasibility study for the automatic surgical planning method based on statistical model

PURPOSE

In this study, we proposed establishing an automatic computer-assisted surgical planning approach based on average population models.

METHODS

We built the average population models from humerus datasets using the Advanced Normalization Toolkits (ANTs) and Shapeworks. Experiments include (1) evaluation of the average population models before surgical planning and (2) validation of the average population models in the context of predicting clinical landmarks on the humerus from the new dataset that was not involved in the process of building the average population model. The evaluation experiment consists of explained variation and distance model. The validation experiment calculated the root-mean-square error (RMSE) between the expert-determined clinical ground truths and the landmarks transferred from the average population model to the new dataset. The evaluation results and validation results when using the templates built from ANTs were compared to when using the mean shape generated from Shapeworks.

RESULTS

The average population models predicted clinical locations on the new dataset with acceptable errors when compared to the ground truth determined by an expert. However, the templates built from ANTs present better accuracy in landmark prediction when compared to the mean shape built from the Shapeworks.

CONCLUSION

The average population model could be utilized to assist anatomical landmarks checking automatically and following surgical decisions for new patients who are not involved in the dataset used to generate the average population model.

Tranexamic acid administered during cesarean delivery in high-risk patients: maternal pharmacokinetics, pharmacodynamics, and coagulation status

BACKGROUND

Tranexamic acid is frequently administered for postpartum hemorrhage. The World Health Organization recommends 1 g intravenous dosing, repeated once after 30 minutes for ongoing bleeding. Understanding the pharmacokinetics and pharmacodynamics of tranexamic acid in patients at high risk of postpartum hemorrhage may enable dosage tailoring for optimal antifibrinolysis with minimal adverse events, such as thrombosis or renal cortical necrosis.

OBJECTIVE

This study aimed to report tranexamic acid pharmacokinetics and pharmacodynamics after 1 g intravenous dosing during cesarean delivery in patients at risk of hemorrhage. The primary endpoint was tranexamic acid plasma concentration of >10 μg/mL, known to inhibit 80% of fibrinolysis. In addition, the correlation between patient demographics and rotational thromboelastometry coagulation changes were analyzed.

STUDY DESIGN

In this prospective study, 20 women aged 18 to 50 years, ≥23 weeks of gestation undergoing cesarean delivery with at least 1 major (placenta previa, suspected placenta accreta spectrum, or active bleeding) or 2 minor (≥2 previous cesarean deliveries, previous postpartum hemorrhage, chorioamnionitis, polyhydramnios, macrosomia, obesity, or suspected placental abruption) risk factors for postpartum hemorrhage were recruited. The exclusion criteria were allergy to tranexamic acid, inherited thrombophilia, previous or current thrombosis, seizure history, renal or liver dysfunction, anticoagulation, or category III fetal heart tracing. Tranexamic acid 1 g was administered after umbilical cord clamping. Blood samples were drawn at 3, 7, 15, and 30 minutes and then at 30-minute intervals up to 5 hours. Plasma concentrations were evaluated as mean (standard error). Serial rotational thromboelastometry was performed and correlated with tranexamic acid plasma concentrations.

RESULTS

The median age of participants was 37.5 years (interquartile range, 35.0-39.5), and the median body mass index was 28.6 kg/m2 (interquartile range, 24.9-35.0). The median blood loss (estimated or quantitative) was 1500 mL (interquartile range, 898.5-2076.0). Of note, 9 of 20 (45%) received a transfusion of packed red blood cells. The mean peak tranexamic acid plasma concentration at 3 minutes was 59.8±4.7 μg/mL. All patients had a plasma concentration >10 μg/mL for 1 hour after infusion. Plasma concentration was >10 μg/mL in more than half of the patients at 3 hours and fell <10 μg/mL in all patients at 5 hours. There was a moderate negative correlation between body mass index and the plasma concentration area under the curve (r=-0.49; 95% confidence interval, -0.77 to -0.07; P=.026). Rotational thromboelastometry EXTEM maximum clot firmness had a weak positive correlation with longitudinal plasma concentration (r=0.32; 95% confidence interval, 0.21-0.46; P<.001). EXTEM maximum clot lysis was 0% after infusion in 18 patients (90%), and no patient in the study demonstrated a maximum lysis of >15% at any interval from 3 minutes to 5 hours. There was no significant correlation between EXTEM clot lysis at 30 minutes and longitudinal tranexamic acid plasma concentrations (r=0.10; 95% confidence interval, -0.20 to 0.19; P=.252).

CONCLUSION

After standard 1 g intravenous dosing of tranexamic acid during cesarean delivery in patients at high risk of hemorrhage, a plasma concentration of ≥10 μg/mL was sustained for at least 60 minutes. Plasma tranexamic acid levels correlated inversely with body mass index. The concurrent use of rotational thromboelastometry may demonstrate tranexamic acid's impact on clot firmness but not a hyperfibrinolysis-derived trigger for therapy.

Tranexamic acid usage in hip fracture surgery: a meta-analysis and meta-regression analysis of current practice

INTRODUCTION

The use of tranexamic acid (TXA) in hip fracture surgery remains inconclusive. The aim of the present meta-analysis was to assess the role of TXA use in hip fracture surgery, and attempt to disclose possible factors which might influence TXA efficacy and safety.

MATERIALS AND METHODS

A systematic computerized literature search was conducted to retrieve all randomized controlled trials (RCTs) and cohort studies regarding TXA use in hip fracture surgery. Overall efficacy and safety were evaluated. Then, subgroup and meta-regression analyses were conducted to disclose the influence of geographic area, fracture type, administration route, frequency and dosage of TXA, blood transfusion threshold, and follow-up duration on the overall effect.

RESULTS

Thirty-four RCTs and 11 cohort studies were included. Patients receiving TXA had a significant decrease in the need for blood transfusion, reduced total, intra-operative and post-operative blood loss, a decrease in pre- and postoperative hemoglobin difference, without increasing thromboembolic events risk. Subgroup analysis showed that topical TXA had a lower transfusion rate compared with controls, yet the result did not reach statistical significance. Also, TXA had similar efficacy and safety profiles in patients with different frequency and dosage of TXA.

CONCLUSION

Current evidence indicated that intravenous administration of TXA could significantly reduce blood transfusion and blood loss without increasing risk of thromboembolic events. The frequency and dosage of TXA might not alter the beneficial effect. The application of topical TXA should be cautious.

Prophylactic administration of tranexamic acid combined with thromboelastography-guided hemostatic algorithm reduces allogeneic transfusion requirements during pediatric resective epilepsy surgery: A randomized controlled trial

Background: Intraoperative bleeding and allogeneic transfusion remain common problems in pediatric resective epilepsy surgery. Tranexamic acid (TXA) is a widely recommended antifibrinolytic drug that reduces blood loss and transfusion requirements for bleeding patients. Thromboelastography (TEG)-guided hemostatic algorithm is commonly used in bleeding management. This trial was designed to validate the efficacy of a multimodal coagulation therapy involving continuous TXA infusion with TEG-guided hemostatic algorithm in reducing allogeneic exposure risk in pediatric resective epilepsy surgery.

Methods: Eighty-three children undergoing resective epilepsy surgery were randomized into a treatment group (Group T; n = 42) and a control group (Group C; n = 41). Group T received prophylactic TXA (10 mg/kg followed by 5 mg/kg/h) with TEG-guided hemostatic algorithm, whereas Group C received conventional coagulation management. The primary outcome was allogeneic transfusion rate during surgery, and the secondary outcomes were intraoperative blood loss, incidence of postoperative seizures, and thromboembolic events during hospitalization.

Results: The incidence of intraoperative allogeneic transfusion reduced by 34.7% with the use of a multimodal coagulation therapy (19.0% in Group T vs. 53.7% in Group C; RR 0.355, 95% CI 0.179–0.704; p = 0.001). This was mainly triggered by a significant reduction (44.1%) in intraoperative plasma transfusion (7.1% in Group T vs. 51.2% in Group C; RR 0.139, 95% CI 0.045–0.432; p = 0.000). The risk of intraoperative RBC transfusion was lower in Group T than in Group C, but the difference was not statistically significant (14.3% in Group T vs. 29.3% in Group C; RR 0.488, 95% CI 0.202–1.177; p = 0.098). No platelets were transfused in both groups. Further, 19 (45.2%) patients in Group T received fibrinogen concentrates guided by TEG data, whereas 1 (2.4%) patient in Group C received fibrinogen concentrates empirically. There were no significant differences in estimated blood loss and postoperative seizures between the two groups, and no thromboembolic events were observed after surgery.

Conclusion: Prophylactic administration of TXA combined with TEG-guided hemostatic algorithm can be an effective multimodal coagulation strategy for reducing allogeneic transfusion requirements during pediatric resective epilepsy surgery.

Clinical Trial Registration:www.chictr.org.cn/index.aspx, identifier ChiCTR1800016188.

Importance of tranexamic acid in pediatric monosutural craniosynostosis surgery

OBJECTIVE

Tranexamic acid (TXA) is an antifibrinolytic drug that has achieved significant reduction in perioperative blood loss and the quantity of blood transfused in many pediatric surgical procedures, without morbidity. Despite the accumulation of evidence regarding its effectiveness in craniosynostosis repair surgery, TXA is not unanimously employed by pediatric neurosurgery teams. The purpose of this study was to evaluate the impact of the routine use of TXA in a homogeneous population of children who underwent open surgery for monosutural craniosynostosis.

METHODS

The authors retrospectively reviewed 3 cohorts of patients that were subdivided from 2 cohorts surrounding the initiation of TXA (group 1, TXA- [2008-2011] and group 2, TXA+ [2011-2013]) and a third cohort of more recent patients (group 3, TXA+ [2016-2017]). TXA was administered using the same protocol comprising a loading dose of 10 mg/kg over 15 minutes after induction of general anesthesia followed by a 10 mg/kg per hour infusion until skin closure. Patients in all 3 groups underwent similar standardized procedures for scaphocephaly, trigonocephaly, and unicoronal craniosynostosis by the same pediatric neurosurgeon.

RESULTS

Overall, 102 infants were included in the study: 32 infants in group 1, 36 in group 2, and 34 in group 3. Significant reductions in transfusion of packed erythrocytes (PE) and fresh-frozen plasma (FFP) were observed between the TXA- and TXA+ time periods. The median volume of PE transfusion was reduced by > 50% with the use of TXA (42.8 mL/kg in the TXA- group vs 20.0 in the TXA+ groups, p < 0.0001). Reduction in PE transfusion was 100% postoperatively in the TXA+ groups (20.0 mL/kg in the TXA- group vs 0.0 in the TXA+ groups, p < 0.0001). The median volume of FFP transfusion was reduced by 100% with the use of TXA (12.8 mL/kg in the TXA- group vs 0.0 in the TXA+ groups, p < 0.0001). All children in group 1 received a transfusion, whereas 3 children (8%) and 7 children (20%) in groups 2 and 3, respectively, did not. Significant reductions in postoperative drain output were also noted between the TXA- and TXA+ time periods. The total hospital length of stay was significantly lower in the TXA+ groups (p < 0.0001).

CONCLUSIONS

Use of TXA reduced blood loss and the need for transfusions but also decreased the hospital length of stay and, thus, minimized overall medical care costs. Intraoperative administration of TXA in craniosynostosis repair surgery should be routinely used in all centers that practice these procedures.

Use of Tranexamic Acid for Elective Resection of Intracranial Neoplasms: A Systematic Review

BACKGROUND

As an established antifibrinolytic agent, tranexamic acid (TXA) has garnered widespread use during surgery to limit intraoperative blood loss. In the field of neurosurgery, TXA is often introduced in cases of traumatic brain injury or elective spine surgeries; however, its role during elective cranial surgeries is not well established. We report a systematic review of the use of TXA in elective surgical resection of intracranial neoplasms.

METHODS

We performed this systematic review following PRISMA guidelines to identify studies investigating the use of TXA in elective neurosurgical resection of intracranial neoplasms. Variables extracted included patient demographics, surgical indications, type of surgery performed, TXA dose and route of administration, operative duration, blood loss, transfusion rate, postoperative hemoglobin level, and complications.

RESULTS

After careful screening, 4 articles (consisting of 682 patients) met our inclusion/exclusion criteria. The studies included 2 prospective cohort studies, 1 retrospective cohort study, and 1 case series. A χ² test of pooled data demonstrated that patients administered TXA had a significantly decreased need for blood transfusions during surgery (odds ratio, 0.6273; 95% confidence interval, 0.4254-0.9251; P = 0.018). Mean total blood loss was 821.9 mL in the TXA group and 1099.0 mL in the control group across the studies. There was no significant difference in postoperative hemoglobin levels, with a mean of 11.4 g/dL in both the TXA and control groups.

CONCLUSIONS

These results support the use of intraoperative TXA in tumor resection. However, its role in tumor resection has been less well investigated compared with its use in other areas of neurosurgery.

Antifibrinolytics Are Not Associated With Reduced Blood Loss in Minimally-Invasive Endoscopic-Assisted Craniectomy for Repair of Single-Suture Craniosynostosis

ABSTRACT

Minimally-invasive endoscopic-assisted craniectomy (EAC) achieves similar functional and cosmetic outcomes, whereas reducing morbidity risk that is often associated with complex cranial vault reconstruction. Antifibrinolytics (AF) usage to limit blood loss and transfusion requirements during complex cranial vault reconstruction has been studied extensively; however, studies are limited for AF therapy in EAC. The aim of this single-center retrospective observational cohort pilot study was to evaluate whether the use of AF was associated with reduced blood loss in infants undergoing EAC. The authors hypothesized that there would be no difference in blood loss between patients who received AF and those that did not receive AF during EAC. Non-syndromic patients who underwent single-suture EAC were retrospectively evaluated. Primary outcome measure was intraoperative calculated blood loss (mL/kg). Secondary outcome measures included perioperative red blood cells transfusion volumes, number of blood donor exposures, and pediatric intensive care unit and total hospital length of stay. Study cohort demographic and outcome data were analyzed; Fisher exact test was used for categorical data, Student t test was used for continuous data. A P value of < 0.05 was considered statistically significant. Forty-nine EAC patients were included in the study with 34 patients in the AF cohort and 15 patients in the non-AF cohort. There were no significant differences in demographics between the 2 groups. Additionally, there was no significant difference in intraoperative calculated blood loss or any secondary outcome measure. In our single-suture EAC study cohorts, AF administration was not associated with a decrease in blood loss when compared to those that did not receive AF therapy.

Population pharmacokinetics and pharmacodynamics of Tranexamic acid in women undergoing caesarean delivery

AIMS

The population pharmacokinetics (PK) and pharmacodynamics (PD) of tranexamic acid (TXA) have not been studied to prevent postpartum haemorrhage (PPH) in pregnant women. It is unclear which TXA dose assures sufficient PPH prevention. This study investigated population PK/PD of TXA in pregnant women who underwent caesarean delivery to determine the optimal prophylactic doses of TXA for future studies.

METHODS

We analysed concentration (PK) and maximum lysis (PD) data from 30 pregnant women scheduled for caesarean delivery who received 5, 10 or 15 mg/kg of TXA intravenously using population approach.

RESULTS

TXA PK was best described by a two-compartment model with first-order elimination and the following parameters: clearance (between-subject variability) of 9.4 L/h (27.7%), central volume of 10.1 L (47.4%), intercompartmental clearance of 22.4 L/h (66.7%), peripheral volume of 14.0 L (13.1%) and additive error of 1.4 mg/L. The relationship between TXA concentration and maximum lysis was characterized by a sigmoid Emax model with baseline lysis of 97%, maximum inhibition of 89%, IC50 of 6.0 mg/L (65.3%), hill factor of 8.5 (86.3%) and additive error of 7.3%. Simulations demonstrated that 500 and 650 mg of TXA maintained therapeutic targets for 30 minutes and 1 hour, respectively, in 90% of patients.

CONCLUSION

This is the first population PK and PD study of TXA in pregnant women undergoing caesarean delivery. Our analysis suggests that a 650 mg dose provides adequate PPH prophylaxis up to 1 hour, which is less than the currently used 1000 mg of TXA in pregnant women.

ε-Aminocaproic acid versus tranexamic acid in children undergoing complex cranial vault reconstruction for repair of craniosynostosis

Complex cranial vault reconstruction (CCVR) for pediatric craniosynostosis is a high blood loss surgery, for which antifibrinolytic agents have been shown to reduce bleeding and transfusion requirements. The relative efficacy of ε-aminocaproic acid (EACA) versus tranexamic acid (TXA) has not yet been evaluated in this population. The aim of this retrospective study was to compare perioperative blood loss and transfusion in CCVR patients receiving EACA versus TXA. In a CCVR cohort of 95 children, 47 received EACA and 48 received TXA. We found no differences in demographics, adverse outcomes, calculated blood loss (CBL), or transfusion requirements between the two antifibrinolytic groups.

Optimal use of intravenous tranexamic acid for hemorrhage prevention in pregnant women

BACKGROUND

Every 2 minutes, there is a pregnancy-related death worldwide, with one-third caused by severe postpartum hemorrhage. Although international trials demonstrated the efficacy of 1000 mg tranexamic acid in treating postpartum hemorrhage, to the best of our knowledge, there are no dose-finding studies of tranexamic acid on pregnant women for postpartum hemorrhage prevention.

OBJECTIVE

This study aimed to determine the optimal tranexamic acid dose needed to prevent postpartum hemorrhage.

STUDY DESIGN

We enrolled 30 pregnant women undergoing scheduled cesarean delivery in an open-label, dose ranging study. Subjects were divided into 3 cohorts receiving 5, 10, or 15 mg/kg (maximum, 1000 mg) of intravenous tranexamic acid at umbilical cord clamping. The inclusion criteria were ≥34 week's gestation and normal renal function. The primary endpoints were pharmacokinetic and pharmacodynamic profiles. Tranexamic acid plasma concentration of >10 μg/mL and maximum lysis of <17% were defined as therapeutic targets independent to the current study. Rotational thromboelastometry of tissue plasminogen activator-spiked samples was used to evaluate pharmacodynamic profiles at time points up to 24 hours after tranexamic acid administration. Safety was assessed by plasma thrombin generation, D-dimer, and tranexamic acid concentrations in breast milk.

RESULTS

There were no serious adverse events including venous thromboembolism. Plasma concentrations of tranexamic acid increased in a dose-proportional manner. The lowest dose cohort received an average of 448±87 mg tranexamic acid. Plasma tranexamic acid exceeded 10 μg/mL and maximum lysis was <17% at >1 hour after administration for all tranexamic acid doses tested. Median estimated blood loss for cohorts receiving 5, 10, or 15 mg/kg tranexamic acid was 750, 750, and 700 mL, respectively. Plasma thrombin generation did not increase with higher tranexamic acid concentrations. D-dimer changes from baseline were not different among the cohorts. Breast milk tranexamic acid concentrations were 1% or less than maternal plasma concentrations.

CONCLUSION

Although large randomized trials are necessary to support the clinical efficacy of tranexamic acid for prophylaxis, we propose an optimal dose of 600 mg in future tranexamic acid efficacy studies to prevent postpartum hemorrhage.

A New Low Dose of Tranexamic Acid for Decreasing the Rate of Blood Loss in Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis

BACKGROUND

Previous studies have demonstrated that the use of tranexamic acid (TXA) reduces blood loss and transfusion requirements in children undergoing scoliosis surgery. Although TXA is safe and effective, significant adverse events have been reported. Using the lowest effective dose of TXA is advisable. We evaluated a new low dosing regimen for TXA based on an improved pharmacokinetic model and therapeutic plasma concentration. The purpose of this study is to evaluate the effectiveness of this new low dosing regimen in reducing blood loss and transfusion requirements in patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion when compared with a control group who did not receive TXA.

METHODS

We retrospectively reviewed 90 consecutive patients with idiopathic scoliosis undergoing posterior spinal fusion at our institution from 2017 to 2020. Forty patients received TXA at the new dosing regimen (10 mg/kg load, 5 mg/kg/h infusion) and 50 patients were in the non-TXA control group. The same 2 orthopaedic surgeons, working as a team, performed all surgical procedures. We assessed the use of TXA as an independent risk factor for estimated blood loss and transfusion requirement after adjusting for age, surgical duration, body mass index, major coronal curve, and sex.

RESULTS

A comparison of the intraoperative cumulative blood loss in the 2 groups showed a significantly lower blood loss in the TXA group. (583.5±272.0 vs. 479.5±288.7 mL, P=0.03) This difference persisted when blood loss was calculated as percent of total blood volume and per vertebral level. Transfusion requirements were lower in the TXA group (4/50 patients vs. 0/40 patients, P=0.13). No patient in the TXA group required a blood transfusion during their hospitalization.

CONCLUSION

This study is the first to provide evidence that a new low dosing regimen of TXA can significantly reduce blood loss and transfusion requirements for idiopathic scoliosis patients and supports the need for a prospective, randomized clinical trial to confirm these findings.

LEVEL OF EVIDENCE

Level III-retrospective cohort study.

Year in Review: Synopsis of Selected Articles in Neuroanesthesia and Neurocritical Care from 2020

This review is a synopsis of selected articles from neuroscience, neuroanesthesia, and neurocritical care from the year 2020 (January–December 2020). The journals reviewed include anesthesia journals, critical care medicine journals, neurology and neurosurgical journals, as well as high-impact medical journals such as the Lancet, Journal of American Medical Association, New England Journal of Medicine, and Stroke. This summary of important articles will serve to update the knowledge of anesthesiologists and other perioperative physicians who provide care to neurosurgical and neurocritical care patients. In addition, some of the important narrative reviews that are of interest to neuroanesthesiologists are also listed.

The Road to Transfusion-free Craniosynostosis Repair in Children Less Than 24 Months Old: A Quality Improvement Initiative

Introduction:

Pediatric craniofacial reconstruction has historically resulted in extensive blood loss necessitating transfusion. This single-center quality improvement initiative evaluates the impact of perioperative practice changes on the allogeneic transfusion rate for children 24 months and younger of age undergoing craniofacial reconstruction.

Methods:

At project initiation, an appointed core group of anesthesiologists provided all intraoperative anesthetic care for patients undergoing craniofacial reconstruction. Standardized anesthetic guidelines established consistency between providers. Using the Plan-do-check-act methodology, practice changes had been implemented and studied over a 5-year period. Improvement initiatives included developing a temperature-management protocol, using a postoperative transfusion protocol, administering intraoperative tranexamic acid, and a preincisional injection of 0.25% lidocaine with epinephrine. For each year of the project, we acquired data for intraoperative and postoperative allogeneic transfusion rates.

Results:

A cohort of 119 pediatric patients, ages 4–24 months, underwent anterior or posterior vault reconstruction for craniosynostosis at a tertiary children’s hospital between March 2013 and November 2018. Intraoperative and postoperative transfusion of allogeneic blood products in this cohort decreased from 100% preintervention to 22.7% postintervention.

Conclusions:

Interdepartmental collaboration and practice modifications using sequential Plan-do-check-act cycles resulted in a bundle of care that leads to a sustainable decrease in the rate of intraoperative and postoperative allogeneic blood transfusions in patients less than 24 months of age undergoing craniosynostosis repair. This bundle decreases the risk of transfusion-related morbidity for these patients. Other institutions looking to achieve similar outcomes can implement this project.

High-dose versus low-dose tranexamic acid for paediatric craniosynostosis surgery: a double-blind randomised controlled non-inferiority trial

BACKGROUND

Tranexamic acid (TXA) reduces blood loss and transfusion in paediatric craniosynostosis surgery. The hypothesis is that low-dose TXA, determined by pharmacokinetic modelling, is non-inferior to high-dose TXA in decreasing blood loss and transfusion in children.

METHODS

Children undergoing craniosynostosis surgery were enrolled in a two-centre, prospective, double-blind, randomised, non-inferiority controlled trial to receive high TXA (50 mg kg^-1 followed by 5 mg kg^-1 h^-1) or low TXA (10 mg kg^-1 followed by 5 mg kg^-1 h^-1). Primary outcome was blood loss. Low dose was determined to be non-inferior to high dose if the 95% confidence interval (CI) for the mean difference in blood loss was above the non-inferiority margin of -20 ml kg^-1. Secondary outcomes were transfusion, TXA plasma concentrations, and biological markers of fibrinolysis and inflammation.

RESULTS

Sixty-eight children were included. Values were non-inferior regarding blood loss (39.4 [4.4] vs 40.3 [6.2] ml kg^-1 [difference=0.9; 95% CI: -14.2, 15.9]) and blood transfusion (21.3 [1.6] vs 23.6 [1.5] ml kg^-1 [difference=2.3; 95% CI: -2.1, 6.7]) between high-dose (n=32) and low-dose (n=34) groups, respectively. The TXA plasma concentrations during surgery averaged 50.2 (8.0) and 29.6 (7.6) μg ml^-1. There was no difference in fibrinolytic and inflammatory biological marker concentrations. No adverse events were observed.

CONCLUSIONS

Tranexamic acid 10 mg kg^-1 followed by 5 mg kg^-1 h^-1 is not less effective than a higher dose of 50 mg kg^-1 and 5 mg kg^-1 h^-1 in reducing blood loss and transfusion in paediatric craniosynostosis surgery.

CLINICAL TRIAL REGISTRATION

NCT02188576.

Tranexamic Acid for Acute Hemorrhage: A Narrative Review of Landmark Studies and a Critical Reappraisal of Its Use Over the Last Decade

The publication of the Clinical Randomization of an Antifibrinolytic in Significant Hemorrhage-2 (CRASH-2) study and its intense dissemination prompted a renaissance for the use of the antifibrinolytic agent tranexamic acid (TXA) in acute trauma hemorrhage. Subsequent studies led to its widespread use as a therapeutic as well as prophylactic agent across different clinical scenarios involving bleeding, such as trauma, postpartum, and orthopedic surgery. However, results from the existing studies are confounded by methodological and statistical ambiguities and are open to varied interpretations. Substantial knowledge gaps remain on dosing, pharmacokinetics, mechanism of action, and clinical applications for TXA. The risk for potential thromboembolic complications with the use of TXA must be balanced against its clinical benefits. The present article aims to provide a critical reappraisal of TXA use over the last decade and a "thought exercise" in the potential downsides of TXA. A more selective and individualized use of TXA, guided by extended and functional coagulation assays, is advocated in the context of the evolving concept of precision medicine.

Reducing blood loss in pediatric craniosynostosis surgery by use of tranexamic acid

INTRODUCTION

Craniosysnostosis surgical corrections are routine procedures in the pediatric neurosurgical field. However, these procedures result in significant blood loss. Tranexamic acid (TXA) is an antifibrinolytic drug, which has demonstrated a significant reduction in perioperative blood loss in many pediatric surgical procedures such as cardiac surgery and scoliosis surgery. We conducted a systematic review to evaluate protocols of TXA use in pediatric craniosynostosis procedures and its effect on intraoperative blood loss and transfusions.

MATERIAL AND METHODS

A comprehensive literature review of the National Library of Medicine (PubMed) database was performed to identify relevant studies. We included any clinical study reporting on blood loss or blood transfusion for pediatric craniosynostosis surgery with intraoperative use of tranexamic acid, with the following limits: publication date from inception to May 2019; reports in English.

RESULTS

Thirteen studies were eligible for our review. Of the 13 studies, 4 were prospective, randomised, double-blind controlled trials, 9 were retrospective studies, tailored as a "before-after" studies, comparing blood loss and transfusion without/with TXA. TXA significantly decreases the number and volume of packed red blood cell transfusions and the rate of transfusion in children undergoing craniosynostosis surgery. Significantly fewer fresh frozen plasma transfusions were required in the TXA groups in 2 randomised studies. Length of stay in hospital was significantly lower with the use of TXA in three studies. Advantages of TXA administration also include an excellent patient tolerance of side effects, ease of administration and low cost.

CONCLUSION

TXA significantly reduces blood loss and the need for transfusions in children undergoing craniosynostosis surgery. TXA administration should be a routine part of strategy to reduce blood loss and limit transfusions in these procedures.

The efficacy and safety of intravenous tranexamic acid in hip fracture surgery: A systematic review and meta-analysis

OBJECTIVE

The present meta-analysis was conducted to compare the efficacy and safety of intravenous application of tranexamic acid (TXA) with placebo in patients with hip fracture undergoing hip surgeries.

METHODS

PubMed, EMBASE and Cochrane Library were searched from inception until March 2018. A combined searching strategy of subject words and random words was adopted. Only randomized clinical trials were included. The comparisons regarding transfusion rate, total blood loss, intraoperative blood loss, postoperative blood loss, postoperative haemoglobin and postoperative thromboembolic complications were conducted. The meta-analysis was performed using Review Manager 5.3, and the bias evaluation was based on the Cochrane Handbook 5.1.0.

RESULTS

Ten randomized controlled trials published from 2007 to 2018 were included in the meta-analysis. The results showed that there were significant differences in the two groups concerning transfusion rate of allogeneic blood [risk ratio (RR) = 0.66, 95% confidence interval (CI): 0.56 to 0.78, P = 0.003], total blood loss [mean difference (MD) = -273.00, 95% CI: -353.15 to -192.84, P < 0.00001], intraoperative blood loss (MD = -76.63, 95% CI: -139.55 to -13.71, P = 0.02), postoperative blood loss (MD = -125.29, 95% CI: -221.96 to -28.62, P = 0.01) and postoperative haemoglobin (MD = 0.80, 95% CI: 0.38 to 1.22, P = 0.0002). Nonsignificant differences were found in the incidence of thromboembolic events (RR = 1.38, 95% CI: 0.74 to 2.55, P = 0.31).

CONCLUSIONS

This meta-analysis of the available evidence implies that the intravenous route of TXA shows an ability to reduce transfusion requirements and total blood loss, not increasing the incidence of thromboembolic events in patients undergoing hip surgeries.

THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE

The result of this meta-analysis shows that the utilization of intravenous TXA in patients with hip fracture undergoing hip surgeries possesses great potential in reducing blood loss and allogeneic blood transfusion safely.

Tranexamic acid and perioperative bleeding in children: what do we still need to know?

PURPOSE OF REVIEW

Perioperative bleeding and blood product transfusion are associated with significant morbidity and mortality. Prevention and optimal management of bleeding decreases risk and lowers costs. Tranexamic acid (TXA) is an antifibrinolytic agent that reduces bleeding and transfusion in a broad number of adult and pediatric surgeries, as well as in trauma and obstetrics. This review highlights the current pediatric indications and contraindications of TXA. The efficacy and safety profile, given current and evolving research, will be covered.

RECENT FINDINGS

Based on the published evidence, prophylactic or therapeutic TXA administration is a well-tolerated and effective strategy to reduce bleeding, decrease allogeneic blood product transfusion, and improve pediatric patients' outcomes. TXA is now recommended in recent guidelines as an important part of pediatric blood management protocols.

SUMMARY

Based on TXA pharmacokinetics, the authors recommend a dosing regimen of between 10 to 30 mg/kg loading dose followed by 5 to 10 mg/kg/h maintenance infusion rate for pediatric trauma and surgery. Maximal efficacy and minimal side-effects with this dosage regime will have to be determined in larger prospective trials including high-risk groups. Furthermore, future research should focus on determining the ideal TXA plasma therapeutic concentration for maximum efficacy and minimal side-effects.

Antifibrinolytic Agents in Plastic Surgery: Current Practices and Future Directions

BACKGROUND

Prevention of blood loss is a chief consideration in plastic and reconstructive surgery. The antifibrinolytic drugs tranexamic acid and ε-aminocaproic acid have emerged as promising agents to reduce both perioperative blood loss and transfusion requirements. However, published reports in the plastic surgery literature are lacking. The authors sought to summarize the current knowledge of the use of antifibrinolytics in plastic surgery by reviewing the existing literature for clinical outcomes and recommendations.

METHODS

A systematic review of the PubMed, Cochrane, and Google Scholar databases was conducted for publications examining the use of antifibrinolytics in plastic surgery. Studies were abstracted for procedure type, antifibrinolytic dose, time and mode of administration, blood loss, transfusion requirements, and complications.

RESULTS

Thirty-three studies were deemed eligible for inclusion, comprising a total of 1823 patients undergoing plastic surgical procedures with tranexamic acid (n = 1328) and/or ε-aminocaproic acid (n = 495).

CONCLUSIONS

Tranexamic acid and ε-aminocaproic acid are widely used to reduce blood loss and transfusion requirements in craniofacial and orthognathic surgery, without an increased risk of adverse events. Intravenous administration is most commonly used, although topical formulations show similar efficacy with a reduced systemic distribution. Tranexamic acid has also emerged as a promising agent in aesthetic surgery and burn care, due to its favorable safety profile and role in reducing blood loss, achieving an improved surgical field, and reducing edema and ecchymosis. Further investigation of these agents in the fields of burn care, aesthetic surgery, and microsurgery is warranted to standardize protocols for clinical use.

Nebulized Tranexamic Acid Use for Pediatric Secondary Post-Tonsillectomy Hemorrhage

Post-tonsillectomy hemorrhage is a frequent occurrence in the emergency department, and management of potentially life-threatening and ongoing bleeding by the emergency physician is challenging. Limited evidence-based guidelines exist, and practice patterns vary widely. We administered nebulized tranexamic acid to achieve hemostasis in a pediatric patient with associated bleeding cessation prior to definitive operative management.

Craniosynostosis Surgery and the Impact of Tranexamic Acid Dosing

Consensus does not exist regarding the best dosage regimen for using tranexamic acid (TXA) for patients undergoing open calvarial vault remodeling in craniosynostosis surgery. The purpose of this study was to evaluate 2 dosing protocols, as well as the cost of using TXA. Previously, the institutional protocol was to give patients undergoing open calvarial vault remodeling a loading infusion of TXA (10 mg/kg) at the start of their procedure, after which intravenous TXA (5 mg/kg/h) was given throughout surgery and for 24 hours postoperatively. In July 2015, the protocol changed to a reduced postoperative infusion time of 4 hours. A retrospective review was conducted of records of 30 patients who had surgery before the protocol change (24-hour group) and 23 patients whose surgery occurred after the protocol change (4-hour group). The following data were collected: blood volume transfused, hemoglobin levels, estimated blood loss, and intensive care days; and costs of TXA and blood transfusion. Results showed a 4-hour infusion was as effective as a 24-hour infusion for reducing blood loss in patients undergoing craniosynostosis. Transfusion requirements, hemoglobin and hematocrit levels, and estimated blood loss were not significantly different for the groups. The cost of TXA and transfusion in the 4-hour group was significantly less (P < 0.001) than in the 24-hour group. No significant difference in cost existed for patients who received blood transfusion alone versus patients who received the 4-hour TXA infusion.

TRAnexamic acid in hemorrhagic CESarean section (TRACES) randomized placebo controlled dose-ranging pharmacobiological ancillary trial: study protocol for a randomized controlled trial

BACKGROUND

Evidence increases that a high or a standard dose of tranexamic acid (TA) reduces postpartum bleeding. The TRACES pharmacobiological substudy aims to establish a therapeutic strategy in hemorrhagic (H) Cesarean section (CS) with respect to the intensity of fibrinolysis by using innovative assays.

METHOD/DESIGN

The TRACES trial is a multicenter, randomized, double-blind, placebo-controlled, TA dose-ranging study that measures simultaneously plasmatic and uterine and urine TA concentrations and the plasmin peak inhibition tested by a simultaneous thrombin plasmin generation assay described by Van Geffen (novel hemostasis assay [NHA]). Patients undergoing H CS (>800 mL) will receive blindly TA 0.5 g or 1 g or placebo. A non-hemorrhagic (NH) group will be recruited to establish plasmin generation profile. Venous blood will be sampled before, at the end, and then at 30, 60, 120, and 360 min after injection. Uterine bleeding will be sampled after injection. Urine will be sampled 2 h and 6 h after injection. The number of patients entered into the study will be 114 H + 48 NH out of the 390 patients of the TRACES clinical trial.

DISCUSSION

To explore the two innovative assays, a preliminary pilot study was conducted. Blood samples were performed repeatedly in patients undergoing either a H (>800 mL) or NH (<800 mL) CS and in non-pregnant women (NP). H patients received TA (0-2 g). Dose-dependent TA plasmatic concentrations were determined by LC-MS/MS quantification. Plasmin generation and its inhibition were tested in vitro and in vivo using the simultaneous thrombin-plasmin generation assay (STPGA). The pilot study included 15 patients in the H group, ten patients in the NH group, and seven patients in the NP group. TA plasmatic concentration showed a dose-dependent variation. STPGA inter-assay variation coefficients were < 20% for all plasmin parameters. Inter-individual dispersion of plasmin generation capacity was higher in H and NH groups than in NP group. Profile evolution over time was different between groups. This preliminary technical validation study allows TRACES pharmacobiological trial to be conducted.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02797119. Registered on 13 June 2016.

Tranexamic Acid Reduces Blood Loss in Craniosynostosis Surgery

METHODS

The authors retrospectively reviewed 79 patients with craniosynostosis who underwent either bifrontal or biparietal-occipital calvarial vault remodeling before institution of tranexamic acid (TXA) administration (non-TXA group) and 35 patients after institution of TXA administration (TXA group). The patients were analyzed in 2 groups: all open calvarial vault remodeling patients (anterior and posterior) as a whole, and anterior vaults only as a subset analysis. Primary outcomes accessed were: total intraoperative blood transfused, postoperative blood transfused, and estimated blood loss (EBL). Secondary outcomes evaluated were length of stay in the pediatric intensive care unit and hospital length of stay.

RESULTS

When comparing all open calvarial vault remodeling patients, patients who received TXA required significantly less total blood transfusion during their operation (264 cc TXA group versus 428 cc non-TXA, P < 0.0001). Patients who received TXA required no blood transfusions postoperatively, compared with the non-TXA group, in which 45% of patients required postoperative blood transfusion. Weight-based EBL was also significantly lower in those patients receiving TXA (25 cc/kg in the TXA group versus 34 cc/kg in the non-TXA group [P = 0.0143]). All patients required transfusion intraoperatively. Pediatric intensive care unit length of stay was shorter in the TXA group, but there was no significant difference in total hospital length of stay. These findings also reached statistical significance when comparing only the anterior vault patients.

CONCLUSION

Intraoperative TXA administration has a correlation with reduced blood transfusion requirements, as well as EBL, in patients undergoing open calvarial vault remodeling. There were no adverse events related to TXA administration.

Implementation of a Tranexamic Acid Protocol to Reduce Blood Loss During Cranial Vault Remodeling for Craniosynostosis

OBJECTIVE

Pediatric cranial vault remodeling for repair of craniosynostosis is associated with significant blood loss and transfusion requirements. Beginning in 2011, the authors evaluated the impact tranexamic acid (TXA) on blood loss and blood product transfusion for children less than 15 months of age undergoing primary surgical repair of nonsyndromic single suture craniosynostosis.

METHODS

Following institutional review board approval, the authors performed a retrospective study of all children undergoing surgical correction of craniosynostosis at Oregon Health & Science University from 2005 to 2015. All available records were reviewed, and patient data were collected from the time of preoperative evaluation until discharge, comparing patient and clinical variables before and after the implementation of perioperative TXA.

RESULTS

Of a total of 259 patients with craniosynostosis, 187 had nonsyndromic single-suture involvement; 69 of these patients (36.9%) received TXA. A single surgical team (AAK and NRS) performed all operations. Median age at the time of surgery was 8.1 months (interquartile range [IQR] of 6.0-9.8 months). The TXA group had a significant reduction in estimated intraoperative blood loss (26 mL/kg versus 36 mL/kg, P <0.001), cell saver volume transfused 6 mL/kg versus 10 mL/kg, P <0.001), red cell transfusion volume (32 mL/kg versus 42 mL/kg, P <0.001), exposure to plasma transfusion (0% versus 24% P <0.001), exposure to cryoprecipitate transfusion (0% versus 16%, P <0.001), and exposure to platelet transfusion (0% versus 7.6% P = 0.03). Despite reduced red cell transfusion, the TXA-treated patients exhibited similar postoperative hematocrits (30.4 versus 30.3 P = 0.906) to those not treated with TXA. Use of TXA was associated with reduced length of stay (4 days IQR 3-4 versus 4 days IQR 4-5, P <0.001) and reduced postoperative output from surgically placed drains (181 mL versus 311 mL P <0.001). There was no difference in postoperative complications between groups and no deaths in either group.

CONCLUSIONS

The introduction of TXA for nonsyndromic single-suture synostosis repair at our institution has significantly reduced blood loss and blood product and plasma transfusion during and following primary cranial vault remodeling for single suture craniosynostosis. Postoperative hematocrit was similar in the TXA-treated and untreated groups despite reduced red cell transfusion in the treated group. In addition, TXA use in this population has eliminated the need for plasma transfusion, and is associated with a shorter hospital stay. No difference in postoperative complications was observed. Our data provide support for further investigation of TXA treatment to improve clinical outcomes in children undergoing pediatric cranial vault remodeling.

Perioperative bleeding management in pediatric patients

PURPOSE OF REVIEW

Managing the bleeding pediatric patient perioperatively can be extremely challenging. The primary goals include avoiding hypotension, maintaining adequate tissue perfusion and oxygenation, and maintaining hemostasis. Traditional bleeding management has consisted of transfusion of autologous blood products, however, there is strong evidence that transfusion-related side-effects are associated with increased morbidity and mortality in children. Especially concerning is the increased reported incidence of noninfectious adverse events such as transfusion-related acute lung injury, transfusion-related circulatory overload and transfusion-related immunomodulation. The current approach in perioperative bleeding management of the pediatric patient should focus on the diagnosis and treatment of anemia and coagulopathy with the transfusion of blood products only when clinically indicated and guided by goal-directed strategies.

RECENT FINDINGS

Current guidelines recommend that a comprehensive multimodal patient blood management strategy is critical in optimizing patient care, avoiding unnecessary transfusion of blood and blood product and limiting transfusion-related side-effects.

SUMMARY

This article will highlight current guidelines in perioperative bleeding management for our most vulnerable pediatric patients with emphasis on individualized targeted intervention using point-of-care testing and specific coagulation products.

Effects of Tranexamic Acid Based on its Population Pharmacokinetics in Pediatric Patients Undergoing Distraction Osteogenesis for Craniosynostosis: Rotational Thromboelastometry (ROTEMTM) Analysis

Background: Distraction osteogenesis for craniosynostosis is associated with significant hemorrhage. Additionally, patients usually require several transfusions. Tranexamic acid (TXA) is effective for reducing blood loss and the need for transfusions during surgeries. However, the significance of TXA infusion has not been thoroughly described yet. Methods: Forty-eight children undergoing distraction osteogenesis for craniosynostosis were administered intraoperative TXA infusion (loading dose of 10 mg/kg for 15 min, followed by continuous infusion at 5 mg/kg/h throughout surgery; n = 23) or normal saline (control, n = 25). Rotational thromboelastometry (ROTEM^TM) was conducted to monitor changes in coagulation perioperatively. Results: Blood loss during surgery was significantly lower in the TXA-treated group than it was in the control group (81 vs. 116 mL/kg, P = 0.003). Furthermore, significantly fewer transfusions of red blood cells and fresh frozen plasma were required in the TXA group. In the control group, clotting time during the postoperative period was longer than it was during the preoperative period. Similarly, clot strength was weaker during the postoperative period. D-dimer levels dramatically increased in the control group compared with the TXA group after surgery. The duration of mechanical ventilation and the number of postoperative respiratory-related complications were significantly greater in the control group than they were in the TXA group. Conclusions: TXA infusion based on population pharmacokinetic analysis is effective in reducing blood loss and the need for transfusions during the surgical treatment of craniosynostosis. It can also prevent the increase in D-dimer levels without affecting systemic hemostasis.

Is tranexamic acid exposure related to blood loss in hip arthroplasty? A pharmacokinetic-pharmacodynamic study

AIMS

Tranexamic acid (TXA) is an antifibrinolytic agent, decreasing blood loss in hip arthroplasty. The present study investigated the relationship between TXA exposure markers, including the time above the in vitro threshold reported for inhibition of fibrinolysis (10 mg l^-1 ), and perioperative blood loss.

METHODS

Data were obtained from a prospective, double-blind, parallel-arm, randomized superiority study in hip arthroplasty. Patients received a preoperative intravenous bolus of TXA 1 g followed by a continuous infusion of either TXA 1 g or placebo over 8 h. A population pharmacokinetic study was conducted to quantify TXA exposure.

RESULTS

In total, 827 TXA plasma concentrations were measured in 166 patients. A two-compartment model fitted the data best, total body weight determining interpatient variability in the central volume of distribution. Creatinine clearance accounted for interpatient variability in clearance. At the end of surgery, all patients had TXA concentrations above the therapeutic target of 10 mg l^-1 . The model-estimated time during which the TXA concentration was above 10 mg l^-1 ranged from 3.3 h to 16.3 h. No relationship was found between blood loss and either the time during which the TXA concentration exceeded 10 mg l^-1 or the other exposure markers tested (maximum plasma concentration, area under the concentration-time curve).

CONCLUSION

In hip arthroplasty, TXA plasma concentrations were maintained above 10 mg l^-1 during surgery and for a minimum of 3 h with a preoperative TXA dose of 1 g. Keeping TXA concentrations above this threshold up to 16 h conferred no advantage with regard to blood loss.

Pharmacokinetics of tranexamic acid in neonates and infants undergoing cardiac surgery

AIM

Tranexamic acid (TXA) continues to be one of the antifibrinolytics of choice during paediatric cardiac surgery. However, in infants less than 1 year of age, the optimal dosing based on pharmacokinetic (PK) considerations is still under discussion.

METHODS

Forty-three children less than 1 year of age were enrolled, of whom 37 required the use of cardiopulmonary bypass (CPB) and six were operated on without CPB. Administration of 50 mg kg^-1 TXA intravenously at the induction of anaesthesia was followed by 50 mg kg^-1 into the CPB prime in the CPB group. Plasma concentrations of TXA were analysed by gas chromatography-mass spectrometry. PK data were investigated using nonlinear mixed-effect models.

RESULTS

A two-compartment model was fitted, with the main covariates being allometrically scaled bodyweight, CPB, postmenstrual age (PMA). Intercompartmental clearance (Q), peripheral volume (V2), systemic clearance, (CL) and the central volume (V1) were calculated. Typical values of the PK parameter estimates were as follows: CL = 3.78 [95 % confidence interval (CI) 2.52, 5.05] l h^-1 ; central volume of distribution = 13.6 (CI 11.7, 15.5) l; Q = 16.3 (CI 13.5, 19.2) l h^-1 ; V2 = 18.0 (CI 16.1, 19.9) l. Independently of age, 10 mg kg^-1 TXA as a bolus, a subsequent infusion of 10 mg kg^-1 h^-1 , then a 4 mg kg^-1 bolus into the prime and a reduced infusion of 4 mg kg^-1 h^-1 after the start of CPB are required to maintain TXA concentrations continuously above 20 μg ml^-1 , the threshold value for an effective inhibition of fibrinolysis and far lower than the usual peak concentrations (the '10-10-4-4 rule').

CONCLUSIONS

The introduction of a modified dosing regimen using a starting bolus followed by an infusion and a CPB prime bolus would prohibit the potential risk of seizures caused by high peak concentrations and also maintain therapeutic plasma concentration above 20 μg ml^-1 .

Safety of antifibrinolytics in cranial vault reconstructive surgery: a report from the pediatric craniofacial collaborative group

BACKGROUND

Antifibrinolytic therapy significantly decreases blood loss and transfusion in pediatric cranial vault reconstructive surgery; however, concern regarding the side effects profile limits clinical use.

AIMS

The aim was to utilize the Pediatric Craniofacial Surgery Perioperative Registry database to identify the safety profile of antifibrinolytic therapy for cranial vault reconstructive surgery by reporting the incidence of adverse events as they relate to exposure to tranexamic acid and aminocaproic acid compared to no exposure to antifibrinolytics.

METHODS

The database was queried for cases of open cranial vault reconstructive surgery. Less invasive procedures such as neuro-endoscopic and spring-mediated cranioplasties were excluded. The outcomes evaluated included any perioperative neurological adverse event including seizures or seizure-like movements and thromboembolic events.

RESULTS

Thirty-one institutions reported a total of 1638 cases from 2010 to 2015. Total antifibrinolytic administration accounted for 59.5% (tranexamic acid, 36.1% and aminocaproic acid, 23.4%), with 40.5% not receiving any antifibrinolytic. The overall incidence of postoperative seizures or seizure-like movements was 0.6%. No significant difference was detected in the incidence of postoperative seizures between patients receiving tranexamic acid and those receiving aminocaproic acid [the odds ratio for seizures being 0.34 (95% confidence interval: 0.07-1.85) controlling for American Society of Anesthesia (ASA) physical class] nor in patients receiving antifibrinolytics compared to those not administered antifibrinolytics (the odds ratio for seizures being 1.02 (confidence interval 0.29-3.63) controlling for ASA physical class). One complicated patient in the antifibrinolytic group with a femoral venous catheter had a postoperative deep venous thrombosis.

CONCLUSIONS

This is the first report of an incidence of postoperative seizures of 0.6% in pediatric cranial vault reconstructive surgery. There was no significant difference in postoperative seizures or seizure-like events in those patients who received the tranexamic acid or aminocaproic acid vs those that did not. This report provides evidence of the safety profile of antifibrinolytic in children having noncardiac major surgery. Caution should prevail however in using antifibrinolytic in high-risk patients. Antifibrinolytic dosage regimes should be based on pharmacokinetic data avoiding high doses.

Effectiveness of tranexamic acid for reducing intraoperative bleeding in palatoplasties: A randomized clinical trial

BACKGROUND

Few data are available regarding blood loss during cleft palate surgery. This study assessed the effect of using tranexamic acid in the reduction of intraoperative bleeding.

METHODS

A double-blind, randomized clinical trial compared intraoperative bleeding and the incidence of oronasal fistulas after palatoplasties in a control group that was given placebo and an intervention group that was given 10 mg/kg tranexamic acid followed by a continuous infusion of 1 mg/kg/h of the same until the end of surgery. Patients who underwent primary palatoplasty with no known or suspected coagulation disorders at our institution during the study period were included in the study.

RESULTS

70 patients were allocated, 66 received the intervention. Blood loss was reduced by 11.9%, without statistical significance. The incidence of fistulas in the intervention and control groups was 12.9% and 18.75%, respectively. The reduction of 5.8% (CI 95%: 12%-23.8%) was not significant.

CONCLUSIONS

The reduction of intraoperative blood loss was lower than expected and not statistically significant; a larger sample is needed to confirm the observed reduction. The drug did not seem to have negative effects on flap viability.

Bleeding management for pediatric craniotomies and craniofacial surgery

Pediatric patients when undergoing craniotomies and craniofacial surgery may potentially have significant blood loss. The amount and extent will be dictated by the nature of the surgical procedure, the proximity to major blood vessels, and the age, and weight of the patient. The goals should be to maintain hemodynamic stability and oxygen carrying capacity and to prevent and treat hyperfibrinolysis and dilutional coagulopathy. Over transfusion and transfusion-related side effects should be minimized. This article will highlight the pertinent considerations for managing massive blood loss in pediatric patients undergoing craniotomies and craniofacial surgery. North American and European guidelines for intraoperative administration of fluid and blood products will be discussed.

Use of tranexamic acid in infants undergoing choroid plexus papilloma surgery: a report of two cases

Choroid plexus papilloma (CPP) is a highly vascular tumor of infancy. Reducing blood loss is the key to successful surgical removal of CPPs. Tranexamic acid (TXA) is efficacious in reducing bleeding in craniofacial surgery for infants. This report demonstrates the potential utility of TXA for decreasing blood loss in the removal of vascular tumors in infants. We administered tranexamic acid to two infants with CPP during surgical removal to potentially aid hemostasis and therefore lessen intra-operative bleeding. Gross total surgical resection was accomplished; the patients were hemodynamically stable perioperatively, and the total calculated blood loss was minimal at <20% of the patients' total circulating blood volume. This is the first report of tranexamic acid administration for CPP surgery in children. TXA is an easily administered hemostatic agent and may merit further study as an agent to help reduce intra-operative blood loss in this vulnerable population.

The efficacy of antifibrinolytic drugs in children undergoing noncardiac surgery: a systematic review of the literature

Children undergoing major surgery are frequently exposed to a high risk of blood loss often requiring transfusion. Although the risks associated with blood product transfusion have considerably decreased over the last decade, transfusion is still associated with significant morbidity and mortality. Thus, rigorous efforts should be made to decrease surgical bleeding and the need for blood product transfusion. Antifibrinolytic drugs have been shown to be effective when used in both adult and pediatric surgical patients. While there are data in adults to support safety, data remain limited for pediatric patients. Since the restriction of aprotinin use in 2008, the most commonly used antifibrinolytic drugs have been the lysine analogs, tranexamic acid (TXA), and ε-aminocaproic acid, which inhibit the conversion of plasminogen to plasmin and decrease the degree of fibrinolysis. We performed a systematic review of the literature pertaining to the efficacy of antifibrinolytic drugs in children undergoing noncardiac surgery. During spine surgery, both TXA and ε-aminocaproic acid decrease blood loss and transfusion requirements; however, this information comes from small, mainly retrospective trials. Two prospective, randomized, controlled trials have tested the efficacy of TXA in children undergoing craniofacial surgery and have reported that TXA decreases transfusion requirements. Two pharmacokinetic trials were also recently published and are summarized in this review. No data have been published regarding the efficacy of TXA administration in the pediatric trauma population. Further data are still needed in this field of study, and we discuss some perspectives for future research.

Major surgical procedures in children with cerebral palsy

There are 3 surgical procedures that patients with cerebral palsy (CP) undergo that may be considered major procedures: femoral osteotomies combined with pelvic osteotomies, spine fusion, and intrathecal baclofen pump implant for the treatment of spasticity. Many complications are known to occur at a higher rate in this population, and some may be avoided with prior awareness of the preoperative pathophysiology of the patient with CP.

Preliminary assessment of zolpidem pharmacokinetics in pediatric burn patients

PURPOSE

Severely burned patients frequently experience sleep fragmentation and insomnia. This study evaluated the population pharmacokinetics of the sleep-enhancing agent zolpidem among burned children.

METHODS

Zolpidem was administered according to the following age-based dosing schedule: 2.5 mg per dose for 2-4 year olds, 5.0 mg per dose for 5-10 year olds, and 10 mg per dose for older than 10 years. Serum samples were collected before and 1, 2, 4, 5, 6, and 8 hours after dosing. The population pharmacokinetic analysis modeled zolpidem concentrations using nonlinear mixed effects models.

RESULTS

Eleven patients with a mean (±SD) age of 8.3 ± 4.0 years and a mean total burn surface area of 56% ± 22% were recruited. Seventy-three zolpidem concentrations were measured with a mean Cmax of 291 ± 140 ng/mL. A 2-compartment model with first-order absorption best described the data. Zolpidem clearance was estimated at 0.03 L·h(-1)·kg(-1) (relative standard error, 55%) and increased with body weight (P < 0.05). The central compartment volume of distribution was estimated at 0.05 L/kg (relative standard error, 25%), which was inversely related to the proportion of the body surface with third-degree burns (P < 0.001).

CONCLUSIONS

A population pharmacokinetic model has been developed that reliably characterized the pharmacokinetic parameters of zolpidem when used as a sleep-enhancing agent among pediatric burn patients. Additional studies are needed to link this pharmacokinetic model with pharmacodynamic data, which may include an assessment of the effects of higher zolpidem doses and/or more frequent administration upon sleep architecture.