Ability of hemostatic assessment to detect bleeding disorders and to predict abnormal surgical blood loss in children: a systematic review and meta-analysis

Point-of-Care Testing in Patients with Hereditary Disorders of Primary Hemostasis: A Narrative Review

Inherited disorders of primary hemostasis, such as von Willebrand disease and congenital platelet disorders, can cause extensive, typically mucocutaneous bleeding. Assays to diagnose and monitor these disorders, such as von Willebrand factor activity assays and light transmission aggregometry, are performed in specialized hemostasis laboratories but are commonly not available in local hospitals. Due to the complexity and relative scarcity of these conventional assays, point-of-care tests (POCT) might be an attractive alternative in patients with hereditary bleeding disorders. POCTs, such as thromboelastography, are increasingly used to assess hemostasis in patients with acquired hemostatic defects, aiding clinical decision-making in critical situations, such as during surgery or childbirth. In comparison, the use of these assays in patients with hereditary hemostasis defects remains relatively unexplored. This review aims to give an overview of point-of-care hemostasis tests in patients with hereditary disorders of primary hemostasis. A summary of the literature reporting on the performance of currently available and experimental POCTs in these disorders is given, and the potential utility of the assays in various use scenarios is discussed. Altogether, the studies included in this review reveal that several POCTs are capable of identifying and monitoring severe defects in the primary hemostasis, while a POCT that can reliably detect milder defects of primary hemostasis is currently lacking. A better understanding of the strengths and limitations of POCTs in assessing hereditary defects of primary hemostasis is needed, after which these tests may become available for clinical practice, potentially targeting a large group of patients with milder defects of primary hemostasis.

[Hemostatic disorders in neurosurgical patients: diagnostics and correction]

The authors analyzed the main causes of perioperative hemostatic disorders in neurosurgical patients. The problem of preoperative hemostatic screening, intraoperative and postoperative factors contributing to hemostatic disorders are considered. The authors also discuss the methods for correction of hemostatic disorders.

Utility of the Pediatric Bleeding Questionnaire in Predicting Posttonsillectomy Bleeding

OBJECTIVE

Posttonsillectomy bleeding is a dreadful complication that may be life-threatening. Preoperative coagulation tests have not been shown to be effective in predicting this complication. The Pediatric Bleeding Questionnaire (PBQ) is a validated and sensitive tool in diagnosing children with abnormal hemostatic functions, and the objective of our study was to assess its utility as a preoperative screening tool for predicting posttonsillectomy bleeding.

STUDY DESIGN

Prospective single-blinded cohort study.

SETTING

Tertiary care hospital system.

METHODS

All children scheduled for tonsil surgery between 2017 and 2019 in the Galilee Medical Center were included. The PBQ was completed by the caregivers prior to surgery, and all children underwent coagulation tests. Each PBQ item is scored on a scale of -1 to 4, and the total score per candidate is based on summation of all items.

RESULTS

An overall 272 patients were included in the study with a mean age of 5.2 years; 57.7% were boys. The main finding was that in a multivariable model adjusted to age, a PBQ score of 2 is correlated with increased postoperative bleeding risk (odds ratio, 10.018 [95% CI, 1.20-82.74]; P = .046). The results of the PBQ demonstrated better predictive ability when compared with abnormal coagulation test results (odds ratio, 1.76 [95% CI, 0.63-4.80]; P = .279). Sex was not found to be significant (odds ratio, 1.45 [95% CI, 0.70-3.18]; P = .343).

CONCLUSIONS

This study demonstrated that a PBQ score ≥2 has a higher yield for detecting children at risk for posttonsil surgery bleeding as compared with coagulation studies.

Perioperative Coagulation Monitoring

The main goal of perioperative coagulation monitoring is to improve safety of patients undergoing surgical procedures. Various conditions can affect the coagulation system during surgery and bleeding. The value of traditional standard coagulation tests is limited in detecting hemostatic dysfunctions and they are particularly ineffective in diagnosing hyperfibrinolysis. This article reports on key issues and pathophysiologic changes that affect the hemostatic system in the perioperative setting. Values of preoperative coagulation tests are discussed and the basic principles for point-of-care coagulation devices, including platelet analyzers and their clinical use, are evaluated.

Post-tonsillectomy hemorrhage control with nebulized tranexamic acid: A retrospective cohort study

OBJECTIVE

Evaluate nebulized tranexamic acid (TXA) as a treatment to reduce the need for an operation to control a post-tonsillectomy hemorrhage (PTH).

METHODS

Based on a successful case report of a child treated with nebulized TXA for PTH in 2018, our institution began to treat PTH patients with three doses of nebulized TXA. To evaluate the outcomes of this non-invasive management, we conducted a three-year retrospective cohort study of children presenting with PTH from 2016 to 2019. Demographics, insurance, and laboratory information were collected from all pediatric tonsillectomies with and without adenoidectomy performed during the study period. Tonsillar fossae observations of bleeding and clot were documented before and after receiving TXA.

RESULTS

The incidence of pediatric PTH at our institution during the study period was 5.4%. Fourteen out of 58 PTH patients received nebulized TXA. Receiving nebulized TXA had no adverse events and over 60% showed resolution of bleeding on exam. Receiving nebulized TXA compared to routine care decreased the need for an operation to restore hemostasis by 44%, p < 0.005. There was no significant difference in age, gender, body mass index, hemoglobin, platelet count, trainee presence, or Medicaid status between the children that received TXA and those that did not.

CONCLUSION

Treatment of PTH with nebulized TXA may be a safe first-line therapy to decrease the need for operative control of bleeding. This data suggests that a large clinical trial is needed to determine the efficacy of nebulized TXA to mitigate this common and potentially fatal post-operative complication.

LEVEL OF EVIDENCE

4.

Preoperative laboratory testing before pediatric neurosurgery: an NSQIP-Pediatrics analysis

OBJECTIVES

The goal of this study was to evaluate clinical predictors of abnormal preoperative laboratory values in pediatric neurosurgical patients.

METHODS

Data obtained in children who underwent a neurosurgical operation were extracted from the prospective National Surgical Quality Improvement Program-Pediatrics (NSQIP-P, 2012-2013) registry. Multivariable logistic regression evaluated predictors of preoperative laboratory values that might require further evaluation (white blood cell count < 2000/μl, hematocrit < 24%, platelet count < 100,000/μl, international normalized ratio > 1.4, or partial thromboplastin time > 45 seconds) or a preoperative transfusion (within 48 hours prior to surgery). Variables screened included patient demographics; American Society of Anesthesiologists (ASA) physical designation classification; comorbidities; recent steroid use, chemotherapy, or radiation therapy; and admission type. Predictive score validation was performed using the NSQIP-P 2014 data.

RESULTS

Of the 6556 patients aged greater than 2 years, 68.9% (n = 5089) underwent laboratory testing, but only 1.9% (n = 125) had a critical laboratory value. Predictors of a laboratory abnormality were ASA class III-V; diabetes mellitus; hematological, hypothrombotic, or oncological comorbidities; nutritional support; recent chemotherapy; systemic inflammatory response syndrome; and a nonelective hospital admission. These 9 variables were used to create a predictive score, with a single point assigned for each predictor. The prevalence of critical values in the validation population (NSQIP-P 2014) of patients greater than 2 years of age was 0.3% with a score of 0, 1.0% in those with a score of 1, 1.6% in those with a score of 2, and 6.2% in those with a score ≥ 3. Higher score was predictive of a critical value (OR 2.33, 95% CI 1.91-2.83, p < 0.001, C-statistic 0.76) and with the requirement of a perioperative transfusion (intraoperatively or within 72 hours postoperatively; OR 1.42, 95% CI 1.22-1.67, p < 0.001) in the validation population. Moreover, when the same score was applied to children aged 2 years or younger, a greater score was predictive of a critical value (OR 2.47, 95% CI 2.15-2.84, p < 0.001, C-statistic 0.76).

CONCLUSIONS

Critical laboratory values in pediatric neurosurgical patients are largely predicted by clinical characteristics, and abnormal preoperative laboratory results are rare in patients older than 2 years of age without comorbidities who are undergoing elective surgery. The NSQIP-P critical preoperative laboratory value scale is proposed to indicate patients with the highest odds of an abnormal value. The scale can assist with triaging preoperative testing based on the surgical risk, as determined by the treating surgeon and anesthesiologist.

Dilutional coagulopathy in pediatric scoliosis surgery: A single center report

BACKGROUND

Children undergoing posterior spinal fusion experience high blood loss often necessitating transfusion. An appropriately activated coagulation system provides hemostasis during surgery, but pathologic dysregulation can cause progressive bleeding and increased transfusions. Despite receiving antifibrinolytics for clot stabilization, many patients still require transfusions.

AIMS

We sought to examine the association of dilutional coagulopathy with blood loss and blood transfusion in posterior spinal fusion for pediatric scoliosis patients.

METHODS

A retrospective, single institution study of children undergoing posterior spinal fusion >6 levels with a standardized, prospective anesthetic protocol utilizing antifibrinolytics. Blood loss was evaluated using a hematocrit-based calculation. To evaluate transfusions, a normalized Blood Product Transfusion calculation was developed. Factors associated with blood loss and blood transfusions were determined by univariate analysis and multivariate regression modeling with multicollinearity and mediation analysis.

RESULTS

Patients received 73.7 mL/kg (standard deviation ±30.8) of fluid poor in coagulation factors. Estimated blood loss was 42.6 mL/kg (standard deviation ±18.0). There was a significant association between estimated blood loss and total fluids delivered (Spearman's rho = 0.51, 95% confidence interval 0.33-0.65, P < 0.001). Factors significantly associated with normalized Blood Product Transfusion in this cohort included age, weight, scoliosis type, levels fused, total osteotomies, pelvic fixation, total fluid, maximum prothrombin time, and minimum fibrinogen. Regression modeling showed the best combination of variables for modeling normalized Blood Product Transfusion included patient weight, number of levels fused, total fluid administered, and maximum prothrombin time.

CONCLUSION

Blood product transfusion remains a frustrating problem in pediatric scoliosis. Identifying and controlling dilutional coagulopathy in these patients may reduce blood loss and the need for blood transfusion.

Choosing Wisely in pediatric anesthesia: An interpretation from the German Scientific Working Group of Paediatric Anaesthesia (WAKKA)

Inspired by the Choosing Wisely initiative, a group of pediatric anesthesiologists representing the German Working Group on Paediatric Anaesthesia (WAKKA) coined and agreed upon 10 concise positive ("dos") or negative ("don'ts") evidence-based recommendations. (i) In infants and children with robust indications for surgical, interventional, or diagnostic procedures, anesthesia or sedation should not be avoided or delayed due to the potential neurotoxicity associated with the exposure to anesthetics. (ii) In children without relevant preexisting illnesses (ie, ASA status I/II) who are scheduled for elective minor or medium-risk surgical procedures, no routine blood tests should be performed. (iii) Parental presence during the induction of anesthesia should be an option for children whenever possible. (iv) Perioperative fasting should be safe and child-friendly with shorter real fasting times and more liberal postoperative drinking and enteral feeding. (v) Perioperative fluid therapy should be safe and effective with physiologically composed balanced electrolyte solutions to maintain a normal extracellular fluid volume; addition of 1%-2.5% glucose to avoid lipolysis, hypoglycemia, and hyperglycemia, and colloids as needed to maintain a normal blood volume. (vi) To achieve safe and successful airway management, the locally accepted airway algorithm and continued teaching and training of basic and alternative techniques of ventilation and endotracheal intubation are required. (vii) Ultrasound and imaging systems (eg, transillumination) should be available for achieving central venous access and challenging peripheral venous and arterial access. (viii) Perioperative disturbances of the patient's homeostasis, such as hypotension, hypocapnia, hypothermia, hypoglycemia, hyponatremia, and severe anemia, should not be ignored and should be prevented or treated immediately. (ix) Pediatric patients with an elevated perioperative risk, eg, preterm and term neonates, infants, and critically ill children, should be treated at institutions where all caregivers have sufficient expertise and continuous clinical exposure to such patients. (x) A strategy for preventing postoperative vomiting, emergence delirium, and acute pain should be a part of every anesthetic procedure.

A bleeding assessment tool correlates with intraoperative blood loss in children and adolescents undergoing major spinal surgery

Screening laboratory studies for bleeding disorders are of little predictive value for operative bleeding risk in adults. Predicting perioperative bleeding in pediatric patients is particularly difficult as younger patients often have not had significant hemostatic challenges. This issue is distinctly important for high bleeding risk surgeries, such as major spinal procedures. The aim of this study was to determine if the score of a detailed bleeding questionnaire (BQ) correlated with surgical bleeding in pediatric patients undergoing major spinal surgery. A total of 220 consecutive pediatric patients (mean age 14.2years) undergoing major spinal surgery were administered the BQ preoperatively, as well as having routine screening laboratory studies (i.e., PT, aPTT, PFA) drawn. A retrospective analysis was conducted to determine if there was a correlation between either the results of the BQ and/or laboratory studies with operative outcomes. A BQ score>2 showed a strong positive correlation with intraoperative bleeding based on both univariate and multivariate analyses. In contrast, abnormalities in screening laboratory studies showed no significant correlation with operative bleeding outcomes. Relying on screening laboratory studies alone is inadequate. The BQ used here correlated with increased intraoperative hemorrhage, suggesting this tool may be useful for assessing pediatric surgical bleeding risk, and may also be useful in identifying a subset of patients with a very low bleeding risk that may not require laboratory screening.

Utility of preoperative in vitro platelet function tests for predicting bleeding risk in patients undergoing functional endoscopic sinus surgery

Background

It is necessary to predict the bleeding risk in patients undergoing functional endoscopic sinus surgery (FESS). To evaluate the adequacy of primary hemostasis, preoperative hemostatic screening tests are used. In the present study, we determined whether there is a positive correlation between prolonged closure time (CT) with collagen/epinephrine (CT-epi), prothrombin time (PT), international normalized ratio (INR), activated partial thromboplastin time (aPTT) and bleeding during FESS.

Patients and methods

We reviewed the medical records of 90 patients without bleeding histories who had undergone FESS from March 2013 to June 2014. More than 200 mL of blood loss was defined as moderate bleeding during surgery. With respect to bleeding during surgery, we determined the sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV) of CT-epi, PT, INR and aPTT.

Results

Of the 90 patients, 17 (18.9%) patients had preoperative prolonged CT values and three (17.6%) patients had bleeding. In comparison, five (6.8%) of the 73 (81.1%) patients who had undergone FESS with preoperative normal PFA values experienced bleeding (P=0.171). On the other hand, patients with prolonged PT values (2, 2.2%), prolonged INR values (3, 3.3%) or prolonged PTT values (1, 1.1%) had no bleeding episode. Preoperative CT had low sensitivity (44.4%) and PPV (23.5%).

Conclusion

During preoperative period, the hemostatic screening may not be helpful to detect the bleeding tendency in adult patients undergoing FESS. Routine measurement of CT-epi, PT, INR and aPTT for preoperative screening may not be recommended for FESS patients.

Noteworthy Literature in 2015

This article is a review of the literature published during the 12 months of 2015, which is of interest to the congenital cardiac anesthesiologist. While the review is not exhaustive, it identifies 7 themes in the literature for 2015 and cites 78 peer-reviewed publications.