Minimizing perioperative blood loss and transfusions in children

Nausea and Vomiting After Posterior Spinal Fusion in Adolescent Idiopathic Scoliosis: A Systematic and Critical Analysis Review

BACKGROUND

Postoperative nausea and vomiting (PONV) affects patient satisfaction, health care costs, and hospital stay by complicating the postoperative recovery period after adolescent idiopathic scoliosis (AIS) spinal fusion surgery. Our goal was to identify recommendations for optimal management of PONV in AIS patients undergoing posterior spinal fusion (PSF).

METHODS

We performed a systematic review in June 2022, searching the PubMed and Embase electronic databases using search terms "(Adolescent idiopathic scoliosis) AND (Postoperative) AND (Nausea) AND (Vomiting)." Three authors reviewed the 402 abstracts identified from January 1991 to June 2022. Studies that included adolescents or young adults (<21 years) with AIS undergoing PSF were selected for full-text review by consensus. We identified 34 studies reporting on incidence of PONV. Only 6 studies examined PONV as the primary outcome, whereas remaining were reported PONV as a secondary outcome. Journal of Bone and Joint Surgery Grades of recommendation were assigned to potential interventions or clinical practice influencing incidence of PONV with respect to operative period (preoperative, intraoperative, and postoperative period) on the basis that potential guidelines/interventions for PONV can be targeted at those periods.

RESULTS

A total of 11 factors were graded, 5 of which were related to intervention and 6 were clinical practice-related. Eight factors could be classified into the operative period-1 in the intraoperative period and 7 in the postoperative period, whereas the remaining 3 recommendations had overlapping periods. The majority of grades of recommendations given were inconclusive or conflicting. The statement that neuraxial and postoperative systemic-only opioid therapy have a similar incidence of PONV was supported by good (Grade A) evidence. There was fair (Grade B) and poor evidence (Grade C) to avoid opioid antagonists and nonopioid local analgesia using wound catheters as PONV-reducing measures.

CONCLUSION

Although outcomes after spinal fusion for AIS have been studied extensively, the literature on PONV outcomes is scarce and incomplete. PONV is most commonly included as a secondary outcome in studies related to pain management. This study is the first to specifically identify evidence and recommendations for interventions or clinical practice that influence PONV in AIS patients undergoing PSF. Most interventions and clinical practices have conflicting or limited data to support them, whereas others have low-level evidence as to whether the intervention/clinical practice influences the incidence of PONV. We have identified the need for expanded research using PONV as a primary outcome in patients with AIS undergoing spinal fusion surgery.

Educational Review: Error traps in anesthesia for pediatric liver transplantation

Anesthetic and surgical techniques for the liver transplantation have progressed considerably over the past sixty years; however, this procedure is still fraught with substantial morbidity. To increase the safety culture associated with the liver transplantation, we detail nine error traps associated with anesthesia for pediatric liver transplantation. These potential pitfalls are divided into the operative phases: pre-operative preparation (Failure to have a dedicated anesthesia team for pediatric liver transplantation); pre-anhepatic (Failure to prepare for massive blood loss, Failure to monitor for coagulation abnormalities); anhepatic including reperfusion (Failure to prepare for clamping of the inferior vena cava, Failure to recognize metabolic changes, Failure to maintain homeostasis for reperfusion, Failure to prepare for Post-reperfusion syndrome); and post-anhepatic (Failure to optimize liver perfusion, Failure to maintain hemostatic balance). By offering practical advice on the preparation and treatment of these error traps, we aim to better prepare anesthesiologists to take care of pediatric patients undergoing the liver transplantation.

Development of a preoperative risk score predicting allogeneic red blood cell transfusion in children undergoing spinal fusion

BACKGROUND

Children undergoing spinal fusion often receive blood products. The goal of this study was to develop a preoperative score to help physicians identify those who are at risk of allogeneic red blood cell (RBC) transfusion.

STUDY DESIGN AND METHODS

This retrospective study of children undergoing spinal fusion in the ACS-NSQIP Pediatric database (2016-2019) aimed at identifying risk factors associated with allogeneic RBC transfusion. Univariable logistic regression and multivariable logistic regression were performed using preoperative patient characteristics and aided in the creation of a simplified scoring system.

RESULTS

Out of 13,929 total patients, 2990 (21.5%) were transfused. We created a risk score based on 10 independent predictors of transfusion: age, sex, race, weight < 3rd percentile, American Society of Anesthesiologists physical status classification, cardiac risk factors, hematologic disease, preoperative anemia, deformity type, and number of spinal levels to be fused. Patients in both the training and testing cohorts were assigned a score ranging from 0 (lowest risk) to 21 (highest risk). The developed transfusion risk score showed 77% accuracy in distinguishing patients who did not receive a transfusion during or soon after surgery (AUROC 0.7736 [95% CI, 0.7619-0.7852]) in the training cohort and 77% accuracy (AUROC 0.7732 [95% CI, 0.7554-0.7910]) in the testing cohort.

DISCUSSION

Our score, based on routinely available preoperative data, accurately estimates the risk of allogeneic RBC transfusion in pediatric patients undergoing spinal fusion. Future studies will inform whether patient blood management interventions targeted to high-risk patients can help reduce the need for transfusion and improve outcomes.

Postoperative complications in cirrhotic pediatric deceased donor liver transplantation: Focus on transfusion therapy

Intraoperative transfusions seem associated with patient death and graft failure after PLTx. A retrospective analysis of recipients' and donors' characteristics and transplantation data in a cohort of patients undergoing PLTx from 2002 to 2009 at the Bergamo General Hospital was performed. A two-stage hierarchical Cox proportional hazard regression with forward stepwise selection was used to identify the main risk factors for major complications. In addition, propensity score analysis was used to adjust risk estimates for possible selection biases in the use of blood products. Over the 12-year period, 232 pediatric cirrhotic patients underwent PLTx. One-year patient and graft survival rates were 92.3% and 83.7%, respectively. The Kaplan-Meier shows that the main decrease in both graft and patient survival occurs during the first months post-transplantation. At the same time, it appears that most of the complications occur during the first month post-transplantation. One-month and 1-year patient complication-free survival rates were 24.8% and 12.1%, respectively. Our study shows that intraoperative red blood cells and platelet transfusions are independent risk factors for developing one or more major complications in the first year after PLTx. Decreasing major complications will improve the health status and overall long-term patient survival after pediatric PLTx.

Predictive factors of intraoperative cell salvage during pediatric scoliosis surgery. Cell saver during scoliosis surgery in children

INTRODUCTION

Blood-saving strategy during spinal surgery in children often includes recombinant erythropoietin (rEPO) and antifibrinolytic therapapy (AFT). The aim of this study was to investigate the efficacy of intraoperative blood salvage in decreasing homologous blood transfusion.

MATERIAL AND METHODS

Using the prospective data from patients operated during a one year period for scoliosis correction, we calculate the predictable hematocrit at day postoperative 1 without the use of blood salvage and compare it to the target hematocrit transfusion according to patient's status. Predictors analyzed were: age, weight, surgical indication, Cobb's angle, ASA status, preoperative hemoglobin, number of level fused, sacral fusion and thoracoplasty. Statistical analyses were performed using a classification tree analysis.

RESULTS

This study included 147 patients. Blood salvage was estimated avoiding homologous blood transfusion in 17 patients. Predictors of the efficacy of blood salvage were: neuromuscular indications, number of level fused and BMI. Blood salvage was found totally ineffective in: patients with no neuromuscular diseases with either: surgeries interesting<13 levels fused or surgeries interesting>13 levels with a preoperative BMI ≥ 21. In all other cases, blood salvage can decrease homologous transfusion. The model exhibited 97% of accurate for the prediction if the inefficacy of blood salvage. The AUCROC of the model was 0.93 [95% confidence interval 0.9 to 0.99] and the overall validation was 60.1% of explained variability.

CONCLUSION

The present study indicates that blood salvage is ineffective under certain circumstances. More studies are mandatory to confirm these results.

Antifibrinolytic agents for reducing blood loss in scoliosis surgery in children

BACKGROUND

This is an updated version of the original Cochrane review first published in 2008. Scoliosis surgery is often associated with substantial blood loss and potentially detrimental effects in children. Antifibrinolytic agents are often used to reduce perioperative blood loss. Clinical trials have evaluated their efficacy in children undergoing surgical correction of scoliosis, but no systematic review has been published. This review was first published in 2008 and was updated in 2016.

OBJECTIVES

To assess the efficacy and safety of aprotinin, tranexamic acid and aminocaproic acid in reducing blood loss and transfusion requirements in children undergoing surgery for correction of idiopathic or secondary scoliosis.

SEARCH METHODS

We ran the search for the previous review in June 2007. For this updated version, we searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 7), MEDLINE (1946 to August week 1 2015), Embase (1947 to 2015 week 38), Latin American Caribbean Health Sciences Literature (LILACS) (1982 to 14 August 2015), Database of Abstracts of Reviews of Effects (DARE; 2015, Issue 2) and reference lists of reviews and retrieved articles for randomized controlled trials in any language. We also checked the clinical trial registry at http://www.clinicaltrials.gov on 8 October 2015.

SELECTION CRITERIA

We included blinded and unblinded randomized controlled trials (RCTs) that evaluated the effects of antifibrinolytics on perioperative blood loss in children 18 years of age or younger and undergoing scoliosis surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data. The primary outcome was total blood loss (intraoperative and postoperative combined). Secondary efficacy outcomes were the number of participants receiving blood transfusion (both autologous and allogeneic) or receiving allogeneic blood transfusion alone, and the total amount of blood transfused. Safety outcomes included the number of deaths, the number of participants reporting any adverse event or a serious adverse event, withdrawals due to adverse events and the number of participants experiencing a specific adverse event (i.e. renal insufficiency, hypersensitivity or thrombosis). We assessed methodological risk of bias for each included study and employed the GRADE approach to assess the overall quality of the evidence.

MAIN RESULTS

We included three new studies (201 participants) in this updated review, for a total of nine studies (455 participants). All but one study employed placebo as the control group intervention. For the primary outcome, antifibrinolytic drugs decreased the amount of perioperative blood loss by 427 mL (95% confidence interval (CI) 251 to 603 mL), for a reduction of over 20% versus placebo. We rated the quality of evidence for our primary outcome as low on the basis of unclear risk of bias for several domains in most studies and the small total number of participants.For secondary outcomes, fewer participants receiving antifibrinolytic drugs received transfusion (allogeneic or autologous) versus those receiving placebo (risk ratio (RR) 0.65, 95% CI 0.50 to 0.85, number needed to treat to prevent one additional harmful outcome (NNTp) 5; very low-quality evidence). Only two studies specifically evaluated the number of participants transfused with only allogeneic blood (risk difference (RD) -0.15, 95% CI -0.26 to -0.03, NNTp 7; very low-quality evidence). Antifibrinolytic drugs decreased the volume of blood transfused by 327 mL (95% CI -186 to -469 mL; low-quality evidence).No study reported deaths in active or control groups. Data were insufficient to allow performance of meta-analysis for any safety outcome. No studies adequately described their methods in assessing safety. The only adverse event of note occurred in one study, when three participants in the placebo group developed postoperative deep vein thrombosis.

AUTHORS' CONCLUSIONS

Since the last published version of this review (2008), we have found three new studies. Additional evidence shows that antifibrinolytics reduce the requirement for both autologous and allogeneic blood transfusion. Limited evidence of low to very low quality supports the use of antifibrinolytic drugs for reducing blood loss and decreasing the risk, and volume, of transfusion in children undergoing scoliosis surgery. Evidence is insufficient to support the use of a particular agent, although tranexamic acid may be preferred, given its widespread availability. The optimal dose regimen for any of these three agents has not been established. Although adverse events appear to occur infrequently, evidence is insufficient to confirm the safety of these agents, particularly for rare but potentially catastrophic events. No long-term safety data are available.

Pediatric Patient Blood Management Programs: Not Just Transfusing Little Adults

Red blood cell transfusions are a common life-saving intervention for neonates and children with anemia, but transfusion decisions, indications, and doses in neonates and children are different from those of adults. Patient blood management (PBM) programs are designed to assist clinicians with appropriately transfusing patients. Although PBM programs are well recognized and appreciated in the adult setting, they are quite far from standard of care in the pediatric patient population. Adult PBM standards cannot be uniformly applied to children, and there currently is significant variation in transfusion practices. Because transfusing unnecessarily can expose children to increased risk without benefit, it is important to design PBM programs to standardize transfusion decisions. This article assesses the key elements necessary for a successful pediatric PBM program, systematically explores various possible pediatric specific blood conservation strategies and the current available literature supporting them, and outlines the gaps in the evidence suggesting need for further/improved research. Pediatric PBM programs are critically important initiatives that not only involve a cooperative effort between pediatric surgery, anesthesia, perfusion, critical care, and transfusion medicine services but also need operational support from administration, clinical leadership, finance, and the hospital information technology personnel. These programs also expand the scope for high-quality collaborative research. A key component of pediatric PBM programs is monitoring pediatric blood utilization and assessing adherence to transfusion guidelines. Data suggest that restrictive transfusion strategies should be used for neonates and children similar to adults, but further research is needed to assess the best oxygenation requirements, hemoglobin threshold, and transfusion strategy for patients with active bleeding, hemodynamic instability, unstable cardiac disease, and cyanotic cardiac disease. Perioperative blood management strategies include minimizing blood draws, restricting transfusions, intraoperative cell salvage, acute normovolemic hemodilution, antifibrinolytic agents, and using point-of-care tests to guide transfusion decisions. However, further research is needed for the use of intravenous iron, erythropoiesis-stimulating agents, and possible use of whole blood and pathogen inactivation. There are numerous areas where newly formed collaborations could be used to investigate pediatric transfusion, and these studies would provide critical data to support vital pediatric PBM programs to optimize neonatal and pediatric care.

Use of Tranexamic Acid (TXA) on reducing blood loss during scoliosis surgery in Chinese adolescents

Background

Many reports had been received on the application of antifibrinolytic medications on spinal corrective surgery and the surgical outcome evaluations of its efficacy on reducing blood loss. This study aimed to assess the efficacy of tranexamic acid (TXA) in reducing operative blood loss during posterior spinal fusion for the treatment of severe adolescent idiopathic scoliosis (AIS).

Methods

A retrospective cohort study was carried out on 90 (TXA = 55, Control = 35) AIS girls undergoing posterior spinal surgery. Patients in TXA group used TXA as an antifibrinolytic agent to reduce blood loss, while control group did not. Blood loss, haemoglobin change and amount of blood transfused was estimated from intraoperative measurement by anaesthesiologists. Demographics were compared using Student’s T-test or Chi-square test where appropriate. Linear regression modelling was carried out between the use of TXA and total blood loss with controlling of confounding factors.

Results

Mean age and mean maximum major curve were 15.2 and 73°, and 15.3 and 63° in TXA and control groups respectively. TXA group showed significantly less intra-operative blood loss than the control group from intraoperative measurement (1.8 L vs. 3.9 L, p < 0.01) and volume of cell saver blood transfused back to patients (0.6 L vs. 1.7 L, p < 0.01). TXA group also showed significantly shorter total time taken for surgery (437 min vs. 502 min, p < 0.01), and total blood loss per surgical segment level (0.1 L vs. 0.3 L, p < 0.01). Regression models showed that the use of TXA decreased total blood loss by 794.3 ml after adjusting for maximum major curve, age, number of segments fused, bone graft, clotting capability, and infusion of coagulation factors.

Conclusions

Patients undergoing posterior spinal corrective surgery with the use of TXA showed much reduced total blood loss, reduced use of transfused blood, much less cell saver blood transfused back to the patient. The total blood loss was decreased by after using TXA after controlling for maximum major curve, age, surgical parameters, clotting capability, and infusion of coagulation factors.

Predicting operative blood loss during spinal fusion for adolescent idiopathic scoliosis

BACKGROUND

Patient and surgical factors are known to influence operative blood loss in spinal fusion for adolescent idiopathic scoliosis (AIS), but have only been loosely identified. To date, there are no established recommendations to guide decisions to predonate autologous blood, and the current practice is based primarily on surgeon preference. This study is designed to determine which patient and surgical factors are correlated with, and predictive of, blood loss during spinal fusion for AIS.

METHODS

Retrospective analysis of 340 (81 males, 259 females; mean age, 15.2 y) consecutive AIS patients treated by a single surgeon from 2000 to 2008. Demographic (sex, age, height, weight, and associated comorbidities), laboratory (hematocrit, platelet, PT/PTT/INR), standard radiographic, and perioperative data including complications were analyzed with a linear stepwise regression to develop a predictive model of blood loss.

RESULTS

Estimated blood loss was 907±775 mL for posterior spinal fusion (PSF, n=188), 323±171 mL for anterior spinal fusion (ASF, n=124), and 1277±821 mL for combined procedures (n=28). For patients undergoing PSF, stepwise analysis identified sex, preoperative kyphosis, and operative time to be the most important predictors of increased blood loss (P<0.05). For ASF, the mean arterial pressure at incision and the operative time were predictive (P<0.05). The following formula was developed to estimate blood loss in PSF: blood loss (mL)=C+Op-time (min)×(6.4)-pre-op T2-T12 kyphosis (degrees)×(8.7), C=233 if male and -270 if female.

CONCLUSION

We find sex, operative time, and preoperative kyphosis to be the most important predictors of increased blood loss in PSF for AIS. Mean arterial pressure and operative time were predictive of estimated blood loss in ASF. For posterior fusions, we also present a model that estimates blood loss preoperatively and can be used to guide decisions regarding predonation of blood and the use of antifibrinolytic agents.

LEVEL OF EVIDENCE

Retrospective study: Level II.

The impact of perioperative transfusion of blood products on survival after pediatric liver transplantation

Intraoperative transfusion of red blood cells (RBC) is associated with adverse outcome after LT in adult patients. This relationship in pediatric patients has not been studied in depth, and its analysis is the scope of this study. Forty-one variables associated with outcome, including blood product transfusions, were studied in a cohort of 243 pediatric patients undergoing a cadaveric LT between 2002 and 2009 at the General Hospital of Bergamo. Multivariate stepwise Cox proportional hazards models were adopted with adjustment by propensity scores to minimize factors associated with the use of blood products. Median age at transplant was 1.37 yr. In uni- and multivariate analyses, perioperative transfusion of FFP and RBC was an independent risk factor for predicting one-yr patient and graft survival. The effect on one-yr survival was dose-related with a hazard ratio of 3.15 for three or more units of RBC (p = 0.033) and 3.35 for three or more units of FFP (p = 0.021) when compared with 1 or no units transfused. The negative impact of RBC and FFP transfusion was confirmed by propensity score-adjusted analysis. These findings may have important implications for transfusion practice in the LT pediatric recipients.

Effect of tranexamic acid on surgical bleeding: systematic review and cumulative meta-analysis

OBJECTIVE

To assess the effect of tranexamic acid on blood transfusion, thromboembolic events, and mortality in surgical patients.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Cochrane central register of controlled trials, Medline, and Embase, from inception to September 2011, the World Health Organization International Clinical Trials Registry Platform, and the reference lists of relevant articles.

STUDY SELECTION

Randomised controlled trials comparing tranexamic acid with no tranexamic acid or placebo in surgical patients. Outcome measures of interest were the number of patients receiving a blood transfusion; the number of patients with a thromboembolic event (myocardial infarction, stroke, deep vein thrombosis, and pulmonary embolism); and the number of deaths. Trials were included irrespective of language or publication status.

RESULTS

129 trials, totalling 10,488 patients, carried out between 1972 and 2011 were included. Tranexamic acid reduced the probability of receiving a blood transfusion by a third (risk ratio 0.62, 95% confidence interval 0.58 to 0.65; P<0.001). This effect remained when the analysis was restricted to trials using adequate allocation concealment (0.68, 0.62 to 0.74; P<0.001). The effect of tranexamic acid on myocardial infarction (0.68, 0.43 to 1.09; P = 0.11), stroke (1.14, 0.65 to 2.00; P = 0.65), deep vein thrombosis (0.86, 0.53 to 1.39; P = 0.54), and pulmonary embolism (0.61, 0.25 to 1.47; P=0.27) was uncertain. Fewer deaths occurred in the tranexamic acid group (0.61, 0.38 to 0.98; P = 0.04), although when the analysis was restricted to trials using adequate concealment there was considerable uncertainty (0.67, 0.33 to 1.34; P = 0.25). Cumulative meta-analysis showed that reliable evidence that tranexamic acid reduces the need for transfusion has been available for over 10 years.

CONCLUSIONS

Strong evidence that tranexamic acid reduces blood transfusion in surgery has been available for many years. Further trials on the effect of tranexamic acid on blood transfusion are unlikely to add useful new information. However, the effect of tranexamic acid on thromboembolic events and mortality remains uncertain. Surgical patients should be made aware of this evidence so that they can make an informed choice.

Transfusion-free anesthetic management for open heart surgery in a neonate -A case report-

In small infants or neonates, open heart surgery without transfusion can have many risks regarding inadequate oxygen delivery and coagulopathy. However, if parents refuse blood transfusion, cardiac surgery without transfusion should be considered. We report a case of bloodless cardiac surgery in a 2.89 kg neonate with Jehovah's Witness parents. Blood conserving strategies were used. Preoperatively, erythropoietin and iron were supplemented to increase the hemoglobin level. Intraoperatively, techniques for minimizing blood loss were used, such as reducing priming volume for cardiopulmonary bypass, a blood salvage system, and modified ultrafiltration. Postoperatively, pharmacologic agents were administered and blood sampling was minimized.

Risk management in pediatric surgery

PURPOSE

To present the experience documented over 1 year of analysis and quality control on surgical complications and organizational accidents.

METHODS

All children admitted during the study period at our Institution were included in the analysis, which consisted of four phases: (1) definition and standardization of perioperative diagnostic and therapeutic tracks; (2) staff education; (3) documentation and data implementation, and (4) "Morbidity and Mortality" audit.

RESULTS

Over a 1-year study period, 3,116 children were admitted to our Institution: 2,222 out of 3,116 (71.3%) children underwent a surgical procedure. A total number of 184 complications were recorded in 149 patients. One hundred and seventy-one (92.9%) complications occurred following a surgical procedure. Fifty-six out of 149 complicated patients (37.6%) required a re-operation. Thirty-five out of 184 (19%) complications were classified as organizational. Infection represented the most common complication. All cases of anastomotic dehiscence and perforation, bowel obstruction, and stoma malfunction required reintervention. None of the postoperative bleedings required a second surgical procedure.

CONCLUSION

Although a proper statistical comparison with literature complication rates is not feasible, our experience confirms the importance of quality-control audit in health care systems. Prolonged observation, long-term follow up, and comparison with previous results will represent our future goal.

Aprotinin concentration varies significantly according to cardiopulmonary bypass conditions

Although aprotinin is partially excreted unchanged in the urine, its primary site of metabolism is in the renal lysosomes following proximal tubule resorption. This study tested the hypothesis that plasma aprotinin concentration varies with cardiopulmonary bypass conditions. Thirty-two piglets (weight 13.2 +/- 1.9 kg) received an aprotinin initial dose of 30,000 KIU/kg, a maintenance infusion of 10,000 KIU/kg/h, with a cardiopulmonary bypass (CPB) prime of 30,000 KIU/kg. Aprotinin infusion was terminated at the end of CPB and stopped during hypothermic circulatory arrest (HCA). Piglets were randomized to four groups (n = 8 per group): HCA, 60-minute period at 15 degrees C; low-flow (LF), 10 mL/kg/min low-flow CPB at 25 degrees C; full flow (FF), full flow CPB at 37 degrees C; control at 37 degrees C without CPB. Blood samples were collected at 7 time points: after induction of anesthesia (baseline), after initial dose, 10, 50 and 115 min after start of CPB, just before end of CPB and 30 min after CPB. Plasma aprotinin levels were determined by modified functional assays. Aprotinin levels in the control group were significantly lower at each point after start of CPB than all groups with CPB (p < .001). In particular, during the reperfusion period, aprotinin levels were higher in HCA and LF groups than FF group (p < .05). Throughout CPB, aprotinin levels in the HCA group remained unchanged (p > .40). Bypass conditions affect plasma aprotinin concentration. Recently reported renal and neurological complications with aprotinin use during CPB may reflect excessive dosing and point to the need for real-time monitoring.

[Scoliosis surgery in children from the viewpoint of anaesthesiology]

Anaesthesia for scoliosis surgery in children is a challenge for the paediatric anaesthesiologist. The large range of underlying pathologies causing deranged physiology in an inhomogeneous patient group ranging from neonates to adolescents necessitates diligent and individual preparation for each case. Due to the invasiveness of the operation demanding anaesthetic care is necessary. This review highlights current approaches to monitoring, anaesthetic regimen, positioning of the patient, blood conservation and transfusion, age-related pathophysiology, ventilation and postoperative pain therapy. The introduction of neurophysiologic spinal cord monitoring requires certain adaptations of the anaesthetic regimen to suit technological advances.

Antifibrinolytic agents for reducing blood loss in scoliosis surgery in children

BACKGROUND

Scoliosis surgery is often associated with substantial blood loss and potential detrimental effects in children. Antifibrinolytic agents are often used to reduce perioperative blood loss. Clinical trials have evaluated their effect in children undergoing surgical correction of scoliosis but no systematic review has been published. We performed a systematic review on the efficacy and safety of antifibrinolytic drugs in children undergoing scoliosis surgery.

OBJECTIVES

To assess the efficacy and safety of aprotinin, tranexamic acid and aminocaproic acid in reducing blood loss and transfusion requirements in children undergoing scoliosis surgery.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2007, Issue 3), OVID MEDLINE (1950 to September 3rd 2007), LILACS (1992 to June 20th 2007) and EMBASE (1980 to July 23rd 2007). We also searched conference proceedings from 2003 to 2007 and the clinicaltrials.gov registry. No language restriction was applied.

SELECTION CRITERIA

We included blinded or unblinded randomized controlled trials that evaluated the effect of antifibrinolytics on perioperative blood loss in children that were 18 years of age or younger and undergoing scoliosis surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently performed the data extraction. Primary outcomes were mortality and number of patients transfused. Secondary outcomes were number of patients transfused with allogeneic blood, amount of total blood transfused, total blood loss and adverse events. To assess heterogeneity we used the I(2) test and for the quantitative analysis we used a fixed-effect model.

MAIN RESULTS

Six studies fulfilled the inclusion criteria. The total number of participants was 254, of whom 127 were allocated to placebo and 127 to antifibrinolytic drugs. Aprotinin, tranexamic acid and aminocaproic acid were evaluated in two studies each. All studies had placebo as the control group intervention. There were no deaths or any serious adverse events in any study, in either the active or the control group. The risk of being transfused was similar in patients receiving antifibrinolytic drugs or placebo. Antifibrinolytics drugs decreased the amount of blood transfused by 327 ml (95% CI -469.04 to -185.78) and the amount of blood loss by 427 ml (95% CI -602.51 to -250.56). There was no indication of publication bias, however, we cannot rule it out due to the small number of studies included.

AUTHORS' CONCLUSIONS

The effect of antifibrinolytic drugs on mortality could not be assessed. Antifibrinolytic drugs reduced blood loss and the amount of blood transfused in children undergoing scoliosis surgery; however, their effect on the number of children requiring blood transfusion remains unclear. Aprotinin, tranexamic acid and aminocaproic acid seem to be similarly effective.