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In this study, we assessed the association between preoperative hemoglobin and red blood cell transfusion in children undergoing spine surgery after the implementation of our preoperative iron supplementation protocol.We performed a retrospective analysis of patients who underwent posterior spinal fusion surgery between January 2013 and December 2017 and received preoperative iron supplementation. We used uni- and multivariable logistic regression to determine the association between preoperative hemoglobin level and red blood cell transfusion in patients receiving iron supplementation.A total of 382 patients treated with preoperative oral iron were included. Of these, 175 (45.5%) patients were transfused intraoperatively. Multivariable logistic regression analysis revealed nonidiopathic etiology of the scoliosis (OR 4.178 [95% CI: 2.277-7.668], P .001), the Cobb angle (OR 1.025 [95% CI: 1.010-1.040], P = .001), and number of vertebrae fused (OR 1.169 [95% CI: 1.042-1.312], P = .008) were associated with red blood cell transfusion. In addition, patients with a preoperative hemoglobin ≥ 140 g/L (OR 0.157 [95% CI: 0.046-0.540], P = .003), and hemoglobin between 130 and 140 g/L (OR 0.195 [95% CI: 0.057-0.669], P = .009) were less likely to be transfused compared with patients with preoperative hemoglobin between 120 and 130 g/L (OR 0.294 [95% CI: 0.780-1.082], P = .066) or120 g/L (reference).Our study suggests that higher preoperative hemoglobin levels (130 g/L) are associated with a reduced need for red blood cell transfusion in pediatric patients who have received iron supplementation before undergoing posterior spinal fusion in our institution. The effect of iron supplementation, the optimal dosing, and duration of supplemental iron therapy remains unclear at this time.

Motor-evoked potentials (MEPs) are frequently used in pediatric posterior spinal fusion surgery (PSFS) to detect spinal cord ischemia. Dexmedetomidine is increasingly being used as an adjunct to total intravenous anesthesia, but its effect on MEP amplitude has been variably reported. The purpose of this study was to evaluate the effect of an infusion of dexmedetomidine on the amplitude of MEPs. We performed a retrospective case-control study of 30 pediatric patients who received a 0.5 µg·kg−1·hr−1 infusion of dexmedetomidine, ten patients who received 0.3 µg·kg−1·hr−1 dexmedetomidine, and 30 control patients who did not receive dexmedetomidine during PSFS. Two neurophysiologists reviewed the MEP amplitudes in six muscle groups at three time points: when the patient was turned prone (baseline; T1), one hour after incision (T2), and after exposure of the spine but before insertion of the first screw (T3). In all muscles tested, the mean MEP amplitude was reduced by T3 when dexmedetomidine was infused at 0.5 µg·kg−1·hr−1. The greatest reduction from baseline MEP amplitude was 829 µV (95% confidence interval, 352 to 1230; P < 0.001) seen in first right dorsus interosseous. When dexmedetomidine was infused at 0.3 µg·kg−1·hr−1, there was a significant reduction in MEP amplitude in four of the six muscles tested at T3 compared with the control group. Dexmedetomidine at commonly used infusion rates of 0.3 µg·kg−1·hr−1 or 0.5 µg·kg−1·hr−1 causes a significant decrease in MEP amplitude during pediatric PSFS. We suggest that dexmedetomidine should be avoided in children undergoing PSFS so as not to confuse the interpretation of this important neurophysiological monitor.

Background Preoperative anemia is an important modifiable risk factor for red blood cell (RBC) transfusion in a variety of surgical populations. The primary objective of this study was to examine the association between preoperative anemia and i) transfusion of RBCs within 72 hours of surgery and ii) postoperative clinical outcomes in children undergoing spine arthrodesis surgery. Study design and methods We assembled a retrospective cohort of children included in the American College of Surgeons National Quality Improvement Program Pediatric database who underwent spine arthrodesis surgery from 2012 to 2016. Anemia was defined using age- and sex-specific hematocrit thresholds. Data collected included demographic and surgical characteristics, RBC transfusion within 72 hours, and 30-day postoperative outcomes (postoperative mechanical ventilation, infection, readmission, hospital length of stay, mortality). Multivariable logistic regression analyses were used to identify independent predictors of RBC transfusion and postoperative outcomes. Results We included 9,095 patients in the analysis. Preoperative anemia was present in 14% (n = 1,233) of the population and 67% (n = 6,135) of patients were transfused. Our multivariable logistic regression showed anemia, surgical time > 350 minutes, > 7 vertebral levels fused, neuromuscular disease, and cerebral palsy were all independent predictors of RBC transfusion. Preoperative anemia was also associated with prolonged hospital LOS (adjusted OR: 1.31, 95%CI: 1.11-1.54, p = 0.002). Conclusions In this study of 9,095 children undergoing spine surgery, preoperative anemia was associated with an increased risk of RBC transfusion and prolonged LOS. Further studies are needed to determine if treatment of preoperative anemia can effectively reduce intraoperative RBC transfusion.

Objectives/Hypothesis To examine outcomes following midline posterior glossectomy (MPG) plus lingual tonsillectomy (LT) for the treatment of significant obstructive sleep apnea (OSA) in children with Down syndrome (DS). Methods Patients with DS who had persistent OSA following tonsillectomy and adenoidectomy (TA) and were relatively intolerant of positive airway pressure (PAP) therapy were evaluated by physical examination and sleep/CINE magnetic resonance imaging to determine the etiology of upper airway obstruction. Patients with relative macroglossia underwent MPG plus LT if required. Successful surgical outcome was defined as the resolution of OSA or the ability to tolerate PAP. Results Thirteen children (8 male, 5 female), mean (standard deviation) age 14.2 (4.0) years underwent MPG plus LT. Fifty-four percent of patients were obese (Body mass index [BMI] > 95th centile) and 8% were overweight (BMI 85th–95th centile) preoperatively. All patients underwent pre- and postoperative polysomnography. Postoperatively, the obstructive apnea-hypopnea index fell significantly from 47.0/hour to 5.6/hour (P

To examine outcomes following midline posterior glossectomy (MPG) plus lingual tonsillectomy (LT) for the treatment of significant obstructive sleep apnea (OSA) in children with Down syndrome (DS).Patients with DS who had persistent OSA following tonsillectomy and adenoidectomy (TA) and were relatively intolerant of positive airway pressure (PAP) therapy were evaluated by physical examination and sleep/CINE magnetic resonance imaging to determine the etiology of upper airway obstruction. Patients with relative macroglossia underwent MPG plus LT if required. Successful surgical outcome was defined as the resolution of OSA or the ability to tolerate PAP.Thirteen children (8 male, 5 female), mean (standard deviation) age 14.2 (4.0) years underwent MPG plus LT. Fifty-four percent of patients were obese (Body mass index [BMI]95th centile) and 8% were overweight (BMI 85th-95th centile) preoperatively. All patients underwent pre- and postoperative polysomnography. Postoperatively, the obstructive apnea-hypopnea index fell significantly from 47.0/hour to 5.6/hour (P.05) in normal weight individuals who did not become obese, but not in obese patients or those who became obese postoperatively. Successful surgical outcome was seen in all (N = 6) children who were normal weight or overweight preoperatively compared with none who were obese preoperatively (N = 7).Midline posterior glossectomy and LT are beneficial in normal weight and overweight children with DS who have persistent OSA following TA and are intolerant of PAP therapy. Obesity pre- or postoperatively portends a worse prognosis following MPG, suggesting that aggressive weight loss initiatives should be considered as an adjunct to surgery in this population.4. Laryngoscope, 127:757-763, 2017.

Objective To establish pediatric reference intervals for lymphocyte vitamin C. Design and methods This was a prospective study of 194 well children aged 0–7 years old of mixed ethnicity who had blood drawn for the purpose of this study. Blood was collected during elective surgery under general anesthesia and lymphocytes isolated and stored as frozen ascorbic acid lymphocyte lysates for later HPLC analysis by previously described methodology. Reference intervals were established according to the Clinical and Laboratory Standards Institute (CLSI) and the International Federation of Clinical Chemistry (IFCC) guidelines (C28-A3). Horn–Pesce robust method was used to estimate the 95% confidence interval and 95% reference interval. Results Reference intervals were independent of age or gender and shown to be 12.9–52.8 μg/108 cells (lymphocytes). Conclusion We have defined pediatric reference ranges for lymphocyte vitamin C in healthy, fasted children at a relevant age group (0–7 years). The new reference interval can now be used to more reliably explore possible implications of variation of vitamin C levels on bleeding and other clinical signs.

Cochlear implants stimulate the auditory nerve to enable hearing. Determining appropriate upper and lower limits of stimulation is essential for successful cochlear implantation. The intraoperative evoked stapedius reflex threshold (ESRT) and evoked compound action potential (ECAP) are commonly used to determine the limits of implant stimulation. In this study, we evaluated the dose-related effects of sevoflurane, desflurane, isoflurane, and propofol on the intraoperative ESRT and ECAP.Forty-four children aged 6 mo to 17 yr undergoing cochlear implantation were recruited. Each child was randomly assigned to receive sevoflurane, desflurane, isoflurane, or propofol. Evoked responses were measured by a blinded investigator at end-tidal anesthetic concentrations corresponding to 0, 0.75, and 1.5 age-adjusted minimum alveolar concentration administered in random sequence and at targeted blood concentrations of propofol of 0, 1.5, and 3.0 microg/mL. Data were analyzed using one-way repeated-measures analysis of variance. P0.05 was considered statistically significant.The ESRT increased dose dependently with increasing volatile anesthetic concentration (P0.01). The stapedius reflex was completely abolished by volatile anesthesia in more than half of children. Propofol minimally affected the ESRT. In contrast, the ECAP was unaffected by anesthesia.Volatile anesthetics suppress the stapedius reflex in a dose-dependent manner, suggesting that ESRT measurements acquired during volatile anesthesia will overestimate the maximum comfort level, which may cause discomfort postoperatively and adversely affect the child's adaptation to the implant. We advise against the use of volatile anesthetics for measurement of the stapedius reflex threshold during cochlear implant surgery.

Remifentanil, an ultra short-acting opioid commonly used to supplement general anesthesia, is associated with the development of hyperalgesia that manifests clinically as an increase in postoperative analgesic requirement. This study involving adolescents undergoing scoliosis surgery evaluated whether pre-treatment with morphine prior to commencing remifentanil infusion would decrease the initial 24-hr morphine consumption and pain scores.Forty ASA I-II pediatric patients undergoing surgical correction of idiopathic scoliosis were recruited in a prospective, randomized, double-blind fashion to receive 150 microg x kg(-1) morphine or an equal volume saline prior to commencing remifentanil by infusion. The primary outcome was the initial 24-hr postoperative morphine consumption. Numeric rating scale (NRS) pain scores at rest and on coughing were recorded, as were scores for nausea, vomiting, and sedation and incidences of pruritus.The groups were demographically similar. No differences were observed between groups vis-à-vis the initial 24-hr morphine consumption, NRS pain scores, sedation, nausea, or vomiting.Pre-treatment with 150 microg x kg(-1) morphine did not decrease the initial 24-hr morphine consumption in adolescents who received remifentanil by infusion for surgical correction of idiopathic scoliosis.

Remifentanil-based anesthesia is commonly used to facilitate neurophysiologic monitoring during pediatric scoliosis surgery. Acute opioid tolerance and/or hyperalgesia resulting from remifentanil-based anesthesia may involve activation of N-methyl-D-aspartate systems. We hypothesized that low-dose intraoperative infusion of the N-methyl-d-aspartate antagonist ketamine would suppress the development of tolerance and thereby decrease postoperative morphine consumption in children receiving remifentanil-based anesthesia for scoliosis surgery.Thirty-four adolescents aged 12-18 yr scheduled for scoliosis surgery were randomly assigned to receive intraoperative low-dose ketamine (bolus dose of 0.5 mg/kg followed by continuous infusion of 4 microg.kg(-1).min(-1)) or an equal volume of saline during propofol/remifentanil anesthesia. Cumulative morphine consumption was assessed using a patient-controlled analgesia device for 72 h after surgery. Postoperative morphine consumption, pain scores at rest and during cough, and sedation scores were recorded by a blinded investigator every hour for the first 4 h, every 4 hours for 20 h, and then every 12 hours for 72 h.Cumulative morphine consumption at 24, 48, and 72 h after surgery did not differ significantly between groups (ketamine group: 1.57+/-0.56, 3.05+/-1.14, and 4.46+/-1.53 mg/kg; saline group: 1.60+/-0.53, 2.87+/-1.05, and 4.11+/-1.71 mg/kg, respectively). No differences in pain or sedation scores were found. The duration of anesthesia was similar in the two groups.These data do not support the use of intraoperative low-dose ketamine to prevent the development of remifentanil-induced acute opioid tolerance and/or hyperalgesia during pediatric scoliosis surgery.

STUDY DESIGN Randomized controlled trial. OBJECTIVE.: To determine the effect of low-dose ketamine on the voltage needed to elicit maximal amplitude of the motor-evoked response to transcranial electrical stimulation during propofol/remifentanil anesthesia in children undergoing scoliosis surgery. SUMMARY OF BACKGROUND DATA Motor-evoked potentials (MEPs) are increasingly used to assess the integrity of motor pathways during surgery. Whereas most general anesthetics depress MEP amplitude, the effect of ketamine has been variable, ranging from little or no reduction to an increase in amplitude, suggesting that ketamine may be useful as an agent to facilitate MEP monitoring. We tested the hypothesis that low-dose ketamine would reduce the voltage required to elicit maximal amplitude of the motor-evoked response to transcranial electrical stimulation during propofol/remifentanil anesthesia. METHODS Thirty-four patients 12 to 16 years of age undergoing posterior instrumentation for correction of idiopathic scoliosis were randomly assigned to receive low-dose ketamine (0.5 mg/kg bolus, followed by 4 microg/kg/min infusion) or an equal volume of saline. Anesthesia was maintained using a mixture of 30% oxygen in air, continuous infusion of propofol at a rate of 100 to 150 microg/kg per min, and continuous infusion of remifentanil. Myogenic motor-evoked responses to transcranial electrical stimulation of the motor cortex were recorded. The minimum voltage required to elicit maximal amplitude of the MEP response was determined. Voltage requirements were compared using the Mann-Whitney U rank sum test. P < 0.05 was considered statistically significant. RESULTS No significant difference was found in the minimal voltage needed to elicit maximum amplitude of the MEP response. Median (range) voltage requirements in the ketamine and control groups were 227 V (range, 160-350 V) and 215 V (range, 150-300 V), respectively. CONCLUSION Addition of low-dose ketamine to propofol/remifentanil anesthesia does not significantly reduce the voltage needed to elicit maximum amplitude of the motor-evoked response to transcranial electrical stimulation.

We tested the hypothesis that continuous intraoperative infusion of remifentanil is associated with the development of clinically relevant acute opioid tolerance in adolescents undergoing scoliosis surgery. Thirty adolescents were randomly assigned to receive an intraoperative analgesic regimen consisting of continuous remifentanil infusion or intermittent morphine alone. Postoperative analgesic consumption was assessed with a patient-controlled analgesia device that was used to self-administer morphine. Cumulative postoperative morphine consumption, pain scores, and sedation scores were recorded by a blinded investigator every hour for the first 4 h postoperatively and then every 4 h for a total of 24 h. Cumulative morphine consumption in the remifentanil group was significantly more than that in the morphine group at each time point in the initial 24 h after surgery (P < 0.0001). At 24 h after surgery, cumulative morphine consumption was 30% greater in the remifentanil group (1.65 +/- 0.41 mg/kg) than in the morphine group (1.27 +/- 0.32 mg/kg) (95% confidence interval for the difference, 0.11 to 0.65 mg/kg). Differences in pain and sedation scores were not statistically significant. These data suggest that intraoperative infusion of remifentanil is associated with the development of clinically relevant acute opioid tolerance in adolescents undergoing scoliosis surgery.

We investigate the impact of extraperitoneal and intraperitoneal CO2 insufflation on cardiopulmonary variables in children undergoing laparoscopic surgery.The records of 73 patients who underwent laparoscopic urological surgery between December 2000 and April 2002 were retrospectively reviewed. Data collection included respiratory rate (RR), peak airway pressure (PAP), O2 saturation, end tidal CO2 (ETCO2), heart rate, systolic and diastolic blood pressure, electrocardiogram and insufflation pressure. All variables were recorded before and after CO2 insufflation. Only patients with complete records were included in the analysis.The study included 62 participants. Of the patients 16 boys and 13 girls with a mean age +/- SD of 7.2 +/- 5.1 years underwent extraperitoneal surgeries, 14 partial or total nephrectomy and 5 pyeloplasty. Mean retroperitoneal CO2 insufflation pressure was 12.1 +/- 1.5 mm Hg and mean operative time was 3.6 +/- 1 hours. We operated on 13 children on the right and 16 on the left decubitus lateral position. Significant increase in ETCO2, RR and PAP was recorded after CO2 insufflation in the extraperitoneal group. Use of the left lateral position resulted in a significant increase in ETCO2 (37.1 +/- 3.6 vs 40 +/- 3.8, p = 0.04) after CO2 insufflation compared to the right decubitus lateral position. Transperitoneal surgery was performed in 32 boys and 1 girl with a mean age of 3.8 +/- 4.1 years for cryptorchidism (32) and attempted pyeloplasty (1). Mean intraabdominal CO2 insufflation pressure was 11 +/- 2.4 mm Hg and mean operative time was 1.7 +/- 0.8 hours. A significant increase in RR (16.5 +/- 3.1 vs 17.9 +/- 3.4, p = 0.0002) and PAP (13.2 +/- 4.8 vs 16.1 +/- 5.7, p0.0001), and a decrease in O2 saturation (99.6 +/- 0.6 vs 98.7 +/- 7.1, p = 0.0003) and heart rate (116 +/- 19 vs 113 +/- 18, p = 0.019) were recorded after CO2 insufflation.Our study documented significant hemodynamic and respiratory changes during pediatric laparoscopic surgeries. A similar effect on the respiratory parameters was observed in both groups. Although there were no apparent complications associated with either approach, further prospective studies are warranted to confirm the effect of laparoscopic urological surgery on cardiopulmonary function in children.

STUDY DESIGN Retrospective review of 36 consecutive patients undergoing coronal plane deformity correction with intraoperative skull-femoral traction between 2005 and 2008 with motor evoked potential (MEP)/somatosensory evoked potential monitoring. OBJECTIVE To determine the prevalence and significance of neurophysiological changes with intraoperative skull-femoral traction in adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA Intraoperative skeletal traction can be associated with spinal cord stretching and ischemia with resultant electrophysiological changes. The prevalence and risks of such changes and their clinical significance is unknown. METHODS Thirty-seven procedures involving 36 patients (27 females and 9 males) with a mean age of 14.8 (12-18) years were divided into two groups on the basis of the presence (group 1, n = 18 procedures) or absence (group 2, n = 19) of significant MEP changes with surgery. They were compared with patients undergoing correction without traction (group 3). RESULTS Significant differences among the groups were observed in mean preoperative Cobb angle (86° vs. 70° vs. 59°), mean intraoperative posttraction Cobb angle (50.0° vs. 34.6°), traction index (0.41 vs. 0.50), flexibility index (0.14 vs. 0.27 vs. 0.25), and presence of primary lumbar curves (0% vs. 32% vs. 14%). Initial onset of MEP amplitude loss (group 1) occurred at a mean of 94 (1-257) minutes from the onset of surgery, was bilateral in 13 procedures, and improved at a mean of 5.5 (1-29) minutes after decreasing or removing the traction. At closure, complete bilateral recovery to baseline was observed in 10 procedures, recovery to >50% baseline in five, and recovery to

INTRODUCTION: The development of acute opioid tolerance with potent short-acting opioids such as remifentanil is described in animal studies, but the results of clinical studies are controversial. Remifentanil-based anesthesia is commonly used at our hospital to facilitate neurophysiologic monitoring during scoliosis surgery. We compared postoperative morphine consumption and visual analogue pain scores in children receiving remifentanil/propofol or morphine/propofol anesthesia for scoliosis surgery.