***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Pediatric patients who undergo posterior spinal fusion surgery to correct scoliosis often require multiple blood transfusions . Tranexamic acid is a synthetic antifibrinolytic drug that reduces transfusion requirements in cardiac surgery and total knee arthroplasty . We evaluated the efficacy of prophylactic tranexamic acid to reduce perioperative blood transfusion requirements in a prospect i ve , double-blinded , placebo control study . Forty patients , 9–18 yr of age , were r and omized to either tranexamic acid ( initial dose of 10 mg/kg and infusion of 1 mg · kg−1 · h−1 ) or placebo ( isotonic saline ) . Perioperative management was st and ardized . A uniform transfusion threshold for noncell saved red blood cells was 7.0 g/dL. The total amount of blood transfused in the perioperative period was significantly reduced in the Tranexamic group ( P = 0.045 ) . No thrombotic complications were detected in either group . The administration of prophylactic tranexamic acid in patients with scoliosis undergoing posterior spinal fusion surgery has the potential to reduce perioperative blood transfusion requirements Background : Excessive bleeding often occurs during pediatric scoliosis surgery and is attributed to numerous factors , including accelerated fibrinolysis . The authors hypothesized that administration of tranexamic acid would reduce bleeding and transfusion requirements during scoliosis surgery . Methods : Forty-four patients scheduled to undergo elective spinal fusion were r and omly assigned to receive either 100 mg/kg tranexamic acid before incision followed by an infusion of 10 mg · kg−1 · h−1 during surgery ( tranexamic acid group ) or 0.9 % saline ( placebo group ) . General anesthesia was administered according to a st and ard protocol . Blood loss , transfusion requirements , coagulation parameters , and complications were assessed . Results : In the tranexamic acid group , blood loss was reduced by 41 % compared with placebo ( 1,230 ± 535 vs. 2,085 ± 1,188 ml ; P < 0.01 ) . The amount of blood transfused did not differ between groups ( 615 ± 460 vs. 940 ± 718 ml ; P = 0.08 ) . Administration of tranexamic acid was a multivariate predictor of blood loss , as was American Society of Anesthesiologists physical status and preoperative platelet count . No apparent adverse drug effects occurred in any patient . Conclusion : Intraoperative administration of tranexamic acid significantly reduces blood loss during spinal surgery in children with scoliosis Study Design Retrospective case-control study . Objective The purpose of this study was to assess whether preoperative use of fish oil supplements increases intraoperative blood loss and postoperative bleeding complications during lumbar decompression surgery . Summary of Background Data Omega-3 fatty acids ( n-3FA ) are widely used as over-the-counter supplements because of well-established cardioprotective and antiplatelet effects . Concern over bleeding associated with changes in platelet function have led to prohibiting these supplements before surgery although there are no clinical data available in the spinal surgery literature to guide such recommendations . Methods Ninety-five consecutive patients who underwent posterior-only lumbar decompression by a single surgeon were included . Patients who had taken n-3FA  within 14 days of surgery were compared with a control group with respect to demographics , preoperative use of other anticoagulants , surgical time , estimated intraoperative blood loss , and postoperative complications including reoperation for epidural hematoma and wound infection . Power analysis suggested 11 patients taking n-3FA were necessary to reach statistical significance based on pilot data . Results Sixteen patients took n-3FA supplements , stopping an average of 2.3 days before surgery . These were no significant between-group differences in demographic parameters , use of other anticoagulants , and surgical time . Estimated blood loss was higher in the control group but the difference was not significant ( 154 vs. 138 mL , P=0.53 ) . There were 2 complications related to bleeding in the control group and none in the n-3FA group . Conclusions We found no increase in intraoperative blood loss or postoperative bleeding complications associated with preoperative use of n-3FA supplements up to an average of 2.3 days before surgery . Although further studies are necessary before this finding can be generalized to other types of spinal surgery , our study corroborates findings from investigations in other surgical specialties that suggest preoperative n-3FA is not associated with increased risk of intraoperative and postoperative bleeding BACKGROUND CONTEXT With a significant increase in the number and complexity of spinal deformity corrective surgeries , blood loss , often requiring massive intraoperative transfusions , becomes a major limiting factor during surgery . This scenario is particularly during posterior vertebral column resection ( PVCR ) , where extensive intraoperative blood loss may pose a major risk to the patient , preventing smooth execution of the procedure . Tranexamic Acid ( TXA ) has been used in cardiac and orthopedic surgeries , including major spinal surgeries , to reduce blood loss and transfusion requirements for decades . PURPOSE To assess the efficacy and safety of high doses of TXA in posterior spinal deformity corrective surgery , including PVCR procedures . STUDY DESIGN A retrospective study from a single institution . PATIENT SAMPLE Fifty-nine patients ( age range 7 to 46 years old ) with spinal deformities undergoing spinal corrective surgeries were included . The patients were divided into two groups : the TXA group ( total of 26 patients , including 8 PVCR patients ) and the control group ( total of 33 patients , including 9 PVCR patients ) . OUTCOME MEASURES The analyzed outcome measures included estimated intraoperative blood loss , real blood loss ( RBL ; blood loss/blood volume × 100 % ) , blood transfusion requirements , coagulation parameters , complete blood count , liver function , and renal function . Lower limb vein thrombus , symptomatic pulmonary embolism , symptomatic myocardial infa rct ion , seizures , and acute renal failure were also recorded . METHODS Before skin incision , the patients in the TXA group received an intravenous loading dose of 100 mg/Kg over a 20-minute period , followed by a maintenance infusion of 10 mg/Kg/h until skin closure was completed . The patients in the control group received saline infusion of a similar volume . Statistics included estimated intraoperative blood loss , RBL , blood transfusion requirements , coagulation parameters , complete blood count , liver function , and renal function . All patients in this study were also carefully monitored for consciousness level , breathing status , chest tightness or pain , and urine output after surgery . These were done to detect the presence or absence of pulmonary embolism , myocardial infa rct ion , seizures , and acute renal failure . Patients treated with TXA were examined via vascular ultrasound before and after surgery . RESULTS There were no significant differences in the demographic or surgical traits between the two groups . The blood loss of the patients in the TXA group was 2,441±1,666 mL , whereas that of the control group patients was 4,789±4,719 mL. The difference was statistically significant ( p<.05 ) . The average RBL of the patients in the TXA group was 80.6%±49.6 % versus 160.8%±163.1 % in the control group ( p<.05 ) . The blood transfusion requirements for the patients in the TXA group were significantly less than that in the control group ( p<.05 ) . Blood loss , RBL , and blood transfusion requirements were all significantly lower in the TXA group , compared with the control group among both PVCR patients and non-PVCR patients . In the TXA group , there was an average of 57.4 % reduced blood loss in patients who received PVCR and 39.8 % in patients not receiving PVCR . There were no differences in liver and renal functions between the TXA and control groups . There was no lower limb vein thrombus , symptomatic myocardial infa rct ion , symptomatic pulmonary embolism , seizures , or acute renal failure reported in the TXA group . CONCLUSIONS In our study , high doses of TXA have been shown to effectively control blood loss and reduce the transfusion requirement . This effect was more apparent in patients receiving PVCR . No adverse drug reaction was recorded in the study . In the future , prospect i ve r and omized controlled trials to vali date our results will be necessary . Future studies conducted on older patient cohort may also be necessary to confirm the safety of extending the use of TXA to the older patients Study Design . Prospect i ve study on intraoperative blood loss during lumbar spine surgery . Objective . To evaluate the relationship between airway pressure change due to the patient 's prone position and intraoperative blood loss during lumbar spine surgery . Summary of Background Data . A prone position may increase abdominal pressure . Changes in abdominal pressure may influence airway pressure and cause intraoperative blood loss as a result of epidural venous congestion . Methods . Patients undergoing lumbar spine surgery were placed in a prone position after the administration of general anesthesia .  Peak airway pressure , plateau pressure , mean blood pressure , and heart rate were measured 5 minutes after anesthesia induction and 15 minutes after being placed in a prone position . Intraoperative blood loss was measured at the end of surgery . Results . Mean peak airway pressure was 13.7 ± 1.8 mm Hg while in a supine position and increased to 15.1 ± 2.5 mm Hg after placement in the prone position ( P = 0.002 ) . Plateau pressure was 12.6 ± 2.5 mm Hg while in a supine position and increased to 14.1 ± 1.9 mm Hg after placement in a prone position ( P = 0.0002 ) . Intraoperative blood loss was correlated with peak ( R2= 0.405 ) and plateau ( R2= 0.489 ) airway pressure changes . Conclusion . Increase in airway pressure result ing from placement into a prone position may predict intraoperative surgical blood loss Study Design . Prospect i ve r and omized study . Objectives . To compare two support systems for positioning patients during microdiscectomy ( i.e. , prone on a modified Relton-Hall spine support vs. knee-chest position on an And rews-type table ) regarding their effects on intra-abdominal pressure and surgical bleeding . Summary of Background Data . Intra-abdominal pressure is an indicator of epidural venous pressure , which affects bleeding during microdiscectomy . The ideal patient ’s position during surgery reduces bleeding by minimizing abdominal compression and vertebral venous engorgement . The results of previous studies on the relationship between intra-abdominal pressure and blood loss during spinal surgery are not consistent , and hardly comparable because they used different measurement systems and support frames . Methods . A total of 30 patients with the American Society of Anesthesiologists physical status I or II undergoing elective , single-space lumbar microdiscectomy had their intra-abdominal pressure measured through a urinary bladder catheter , together with airway pressure : ( 1 ) supine after anesthesia induction ; ( 2 ) in prone position ( group P ) or knee-chest position ( group K ) , according to r and omization ; or ( 3 ) at the end of surgery before repositioning the patient supine . Results . Baseline intra-abdominal pressure did not differ between groups , and intra-abdominal pressure did not vary significantly from baseline in both groups throughout the study . Baseline airway pressure did not differ between groups . Airway pressure was significantly increased from baseline at the recording before incision in group K and at the end of surgery in both groups . Recordings before incision and at the end of surgery differed significantly from one another in both groups . Such airway pressure variations did not differ between groups . Bleeding was significantly more prominent in group K ( P = 0.007 ) . No correlation between bleeding and intra-abdominal pressure or airway pressure was found . Conclusions . Intra-abdominal pressure did not differ between prone position on a modified Relton-Hall frame and knee-chest position on an And rew-type table . Bothpositions provide good conditions for lumbar microdiscectomy Study Design . A prospect i ve r and omized comparative study . Objective . To evaluate the effect of tranexamic acid ( TXA ) on decreasing perioperative blood loss in cervical laminoplasty , in which the surgical procedure is identical in all cases . Summary of Background Data . TXA , an inhibitor of fibrinolysis , has proven to be effective in reducing perioperative blood loss in patients undergoing total hip and knee arthroplasty . However , only a limited number of well-controlled spinal surgery trials have been conducted due to heterogeneity in the performed surgical procedures . Methods . Forty consecutive patients with cervical compressive myelopathy were prospect ively r and omized into groups that received 15 mg/kg body weight of TXA or placebo intravenously before the skin incision was made . “ French-door ” cervical laminoplasty from C3 to C6 was performed for all patients by using a consistent procedure . Intraoperative and postoperative blood loss was compared between the groups . The surgery and follow-up were conducted at a single institution . Results . There were no statistically significant differences between the TXA and control groups in terms of age , sex , body mass index , and operating time . Intraoperative blood loss in the TXA group ( 49.1 ± 30.6 mL ) was not significantly different from that in the control group (  
    Output:
    
Several studies have shown a significant reduction in intraoperative bleeding during spine surgery and in the requirement for blood transfusion