The evaluation of propofol dosage for anesthesia induction in children with cerebral palsy with bispectral index (BIS) monitoring

BACKGROUND: We designed a randomized prospective study to investigate whether developmentally delayed children with cerebral palsy (CP) need a lower dosage of propofol for induction than normal children using bispectral index (BIS) monitoring criteria. METHODS: After approval by the University Ethical Committee and written informed consent obtained from parents, 20 children with noncommunicative/nonverbal CP and 20 normal children requiring general anesthesia for elective orthopedic surgery were enrolled in the study. The patients were not premedicated. BIS leads were placed before the induction of anesthesia. Propofol was administered at a rate of 20 mg.30 s(-1) (i.e. 40 mg.min(-1)).When BIS value had reached a steady number of 35-45, infusion was stopped. RESULTS: There was no significant difference between Group N and Group CP in age and sex distribution (P > 0.05), however children in Group CP weighed less than Group N (P = 0.05). The propofol dosage for induction was significantly lower in Group CP than Group N (P = 0.03). There were no differences in propofol doses administered to children using anticonvulsants and those not on anticonvulsants in Group CP. BIS values were comparable between the two groups (i.e. Group N and Group CP) at baseline and after propofol administration. CONCLUSIONS: Our data suggest that noncommunicative/nonverbal children with CP require less propofol to obtain the same BIS values (i.e. 35-45) than do otherwise healthy children.     

改良手术治疗脑瘫痉挛性双侧下肢瘫

[目的]2004年以来对重症脑瘫痉挛性双侧瘫治疗方法进行改进,探索提高其治疗效果的方法.[方法]23例重症脑瘫痉挛性双侧瘫.男14例,女9例;年龄3～12岁,平均5.7岁;主要症状不能独自站立和行走,双下肢肌紧张,家长扶持站立,双下肢呈剪刀步态,双髋、膝关节屈曲,踝关节跖屈,双足马蹄内翻畸形,足尖着地行走.体格检查双髂腰肌、内收肌、腘绳肌、小腿三头肌、胫前肌、胫后肌、(足母)长屈肌、趾长屈肌部分或多数不同程度肌张力增高.依Ashworth分级,为3～4级.治疗方法对动态性肌痉挛,采用肌内肌腱切断或肌筋膜切断;对静态性肌痉挛行肌腱滑动延长,胫前肌腱劈开外侧1/2移位.然后用自制外固定器矫形固定,保持膝关节伸直,双踝、足中立位,双下肢外展30°,6周后去除外固定康复训练.[结果]本组病例随访1～3年,平均2.2年.优良21例,有效2例.[结论]严重脑瘫痉挛性双侧瘫,一期多关节软组织松解,肌力平衡,外固定矫形,术后配合家庭长期康复训练,是一种有效的治疗方法.     

Janeway gastrostomy in children with cerebral palsy

Brain damaged children frequently are unable to eat by mouth due to incoordination of tongue and pharyngeal swallowing muscles. The commonly utilized Stamm gastrostomy has several drawbacks relative to the indwelling catheter. A permanent gastrostomy consisting of a mucosal-lined tube flap from the stomach wall, as described by Janeway, is easily constructed using the GIA stapler. This provides a simple, tubeless, and safe way to feed cerebral palsied children unable to eat by mouth.     

Minimum alveolar concentrations of sevoflurane for maintaining bispectral index below 50 in children

Objective: To determine minimum alveolar concentration (MAC) of sevoflurane for maintaining bispectral index (BIS) below 50 (MAC_BIS50) in children. Background: MAC_BIS50 of sevoflurane in adults was reported to be 0.97%, which has not been elucidated in children. Methods/Materials: Twenty children, American Society of Anesthesiologists physical status I or II, aged 1–8, were induced and anesthetized with sevoflurane in oxygen. After tracheal intubation, we started maintenance of anesthesia with endtidal sevoflurane concentrations of 2.6%. The endtidal sevoflurane concentration at which BIS was measured was predetermined by the up‐down method (with 0.2% as a step size). After 10 min at predetermined endtidal sevoflurane concentrations, BIS was measured for 1 min. MAC_BIS50 was determined using Dixon’s up‐down method and probit test. Result: MAC_BIS50 of sevoflurane was 2.83% (95% confidence intervals: 2.70–3.14) in children. Conclusions: MAC_BIS50 of sevoflurane in children was calculated to be three times as high as in adults. This indicates that high endtidal sevoflurane concentration is required to suppress electroencephalogram activity in children.     

Efficacy of occupational therapy and serial casting in lower limbs of cerebral palsy children administered with phenol nerve block

To see the efficacy of occupational therapy and serial casting over occupational therapy alone in case of sciatic nerve block in cerebral palsy children.In the study 18 spastic cerebral palsy children were treated with in-traneural phenol block (open technique) followed by occupational therapy to bring out functional change. All the 18 patients were administered with intraneural phenol block. In 9 patients serial casting combined with occupational therapy (experimental group) was given while in another group 9 patients were treated with occupational therapy alone (control group). The treatment session for each patient lasted for 6 weeks. To measure the outcome GMFM 66, pediatric balance test (PBT), active range of motion, passive range of motion, modified Ashworth scale were used as tool.There was significant reduction in spasticity of all the 18 patients (after administration of intraneural phenol nerve block) when compared with their pre-operative status. There was significant improvement of gross motor function (GMFM 66), active and dynamic balance (through PBT), and active range of movement of knee joint in experimental group. There was no significant difference between the groups in passive range of motion and reduction of spasticity.The study concludes that intraneural phenol block reduces spasticity in cerebral palsy children to a significant level thus improving the functional outcome in these children. Serial casting when combined with occupational therapy after phenol block gives much better and quicker improvement in gross motor function and motor milestone development.     

Urodynamic findings in children with cerebral palsy

AIM: More than one-third of children with cerebral palsy are expected to present with dysfunctional voiding symptoms. The voiding dysfunction symptoms of the cerebral palsy patients in the present study were documented. METHODS: Of the study group, 16 were girls and 20 were boys (mean age: 8.2 years). Children with cerebral palsy were evaluated with urodynamics consisting of flow rate, filling and voiding cystometry, and electromyography findings of the external urethral sphincter to determine lower urinary tract functions. Treatment protocols were based on the urodynamic findings. Anticholinergic agents to reduce uninhibited contractions and to increase bladder capacity were used as a treatment. Clean intermittent catheterization and behavioral modification were used for incomplete emptying. RESULTS: Of the children, 24 (66.6%) were found to have dysfunctional voiding symptoms. Daytime urinary incontinence (47.2%) and difficulty urinating (44.4%) were the most common symptoms. Urodynamic findings showed that neurogenic detrusor overactivity (involuntary contractions during bladder filling) with a low bladder capacity was present in 17 (47.2%) children, whereas detrusor-sphincter dyssynergia was present in four patients (11%). The mean bladder capacity of patients with a neurogenic bladder was 52.2% of the expected capacity. CONCLUSIONS: The present study concluded that voiding dysfunction was seen in more than half of the children with cerebral palsy, which is a similar result to other published studies. We propose that a rational plan of management of these patients depends on the evaluation of the lower urinary tract dysfunction with urodynamic studies. These children benefit from earlier referral for assessment and treatment.     

One session surgery on the lower limb in children with cerebral palsy

Summary Twenty three children with cerebral palsy, who were operated on upon before 1984, have been re-assessed. All the lower limb deformities were corrected in one surgical session. Review after five years included foot-switch measurements and assessment of video recordings. There were no recurrences, and gait ability showed normal growth-related development.

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Résumé Vingt-trois enfants atteints de paralysie cérébrale, opérés depuis 1984, ont été ré-examinés. Tous avaient été opérés en un temps pour correction de l'ensemble des déformations qu'ils présentaient. Une révision à 5 ans a été réalisée en utilisant la mesure de l'amplitude du pas et l'évaluation d'enregistrements vidéo. On a pris note des rechutes et des opérations complémentaires. Il n'y a pas eu de rechutes. Les possibilités de marche ont augmenté normalement en fonction de la croissance. On en conclut que les opérations justifiées ne sont pas dangereuses pour ces enfants et que la chirurgie en un temps peut diminuer le taux de rechutes.

     

Preoperative caudal block prevents emergence agitation in children following sevoflurane anesthesia

BACKGROUND: The frequency of emergence agitation in children is increased following sevoflurane anesthesia. However, controversies still exist concerning the exact etiology of this postanesthetic problem. Although this phenomenon is present with adequate pain relief or even following pain-free procedures, pain is still regarded as a major contributing factor. METHODS: In a prospective, randomized, double-blind study, we enrolled 48 premedicated and calm 2-6-year-old children undergoing inguinal hernia repair. We assigned children to one of two groups: children assigned to the caudal group (n = 24) received a caudal block to supplement sevoflurane, while children assigned to the fentanyl group (n = 24) received a bolus injection of 1 microg kg(-1) intravenous fentanyl before skin incision to supplement sevoflurane. In the post anesthesia care unit, all children were received by their parent, and the incidence of emergence agitation and pain scores, as well as hemodynamic changes, were compared in both groups. RESULTS: Forty-four children completed the study. In the fentanyl group, 59% of the children were agitated following emergence from anesthesia as compared to 4.5% in the caudal group (P < 0.001). Also, pain scores, mean values of heart rate and blood pressure as well as morphine requirement were significantly higher in the post anesthesia care unit in the fentanyl group compared to the caudal group. CONCLUSION: Our results show that in children undergoing inguinal hernia repair, pain control with a preoperative caudal block as compared to intraoperative intravenous fentanyl significantly reduces the incidence of emergence agitation and pain scores following sevoflurane anesthesia.     

Patients’ and parents’ views about lower limb orthopaedic surgery for ambulant children and young people with cerebral palsy: a qualitative evidence synthesis

PurposeThe article identifies the aspects of health and outcomes that are considered important from the perspective of ambulatory children with cerebral palsy (CP) and their parents regarding lower limb orthopaedic surgery and explores how they experience surgical interventions.MethodsFour databases (Embase, MEDLINE (Ovid), CINAHL and PsycINFO) were searched from inception to 11 April 2020. Studies were included if they: 1) they involved children or young adults diagnosed with ambulant CP or their family, 2) participants had experience with lower limb orthopaedic surgery and 3) studies employed qualitative research methods. The Critical Appraisal Skills Programme was used to appraise identified studies. The ‘Best-fit framework’ synthesis approach was used by applying the International Classification of Functioning-Children and Youth (ICF–CY) linking rules and thematic synthesis. The review process was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.ResultsSix studies were included. Four themes were generated which were linked to the ICF–CY framework: Body function and structure, Activity and participation, Environmental factors, Personal factors, as well as non-ICF–CY themes including Emotional well-being and Goal setting. Important surgical outcomes identified were pain, fatigue, movement-related function, mobility, walking ability, community life, emotional well-being, and adequate provision of public and health services.ConclusionThese findings are important for understanding patient-centred outcomes in lower limb ortho-paedics surgery and providing focus for future interventional studies aimed at improving outcomes of importance to children with CP. These findings highlight the importance of long-term support to help people negotiate the challenge of surgical regimes and to achieve good outcomes after orthopaedic surgery. The outcomes identified will contribute to the development of a core outcome set in this field.Level of evidenceIII     

右美托咪定对脑瘫患儿七氟醚麻醉苏醒期躁动的影响

目的 探讨右美托咪定对脑瘫患儿七氟醚麻醉苏醒期躁动的影响.方法 择期拟行肌力肌张力调整术的脑瘫患儿50例,ASA分级Ⅰ或Ⅱ级,年龄2～12岁,性别不限.采用随机数字表法,将其分为2组(n=25):对照组(C组)和右美托咪定组(D组).D组麻醉诱导后经15 min静脉输注右美托咪定0.5 μg/kg,C组给予等容量生理盐水,给药结束后开始手术,术中吸入2％ ～4％七氟醚维持麻醉,维持BIS值45 ～ 60.于右美托咪定给药前(T1)、切皮时(T2)记录HR、SBP和DBP,记录拔管时间、苏醒时间和麻醉期间七氟醚用量,并于T1、T2、术毕(T3)时记录呼气末七氟醚浓度;记录术中心血管不良事件及苏醒期躁动发生情况,并采用小儿苏醒期烦躁量表(PAED)评价躁动程度;于T1、T2、T3和拨管时(T4)采集外周静脉血样,测定血糖水平和血清皮质醇浓度.结果 与C组比较,D组苏醒时间和拨管时间明显缩短,七氟醚用量、T2和T3时呼气末七氟醚浓度、PAED评分、躁动发生率降低,T4时血糖和血清皮质醇浓度降低(P＜ 0.05或0.01),2组心动过缓发生率以及各时点HR、SBP和DBP比较差异无统计学意义(P＞0.05).结论 右美托咪定可降低脑瘫患儿七氟醚麻醉苏醒期躁动的发生和程度.     

The incidence of avascular necrosis in children with cerebral palsy after hip containment surgery

Purpose:To establish the rate of avascular necrosis after hip reconstruction surgery in children with cerebral palsy and to identify risk factors that influence the development of avascular necrosis in this population.Methods:An institutional review board–approved retrospective review was conducted on children with cerebral palsy who underwent hip containment surgery at a single institution. Radiographs were evaluated at three time points. The Reimer’s migration percentage, neck shaft angle, epiphyseal shaft angle, acetabular index, center edge angle, and acetabular angle were measured. The presence of avascular necrosis was evaluated and graded by the Bucholz/Ogden and the Kalamchi/MacEwen classification systems. Multivariate logistic regression was performed to identify risk factors associated with the development of avascular necrosis.Results:A total of 154 children with cerebral palsy underwent hip containment surgery on 223 hips. Twenty-nine children (18.8%) underwent both pelvic and femoral procedures; 36 children (23.4%) had only femoral procedures; 47 children (30.5%) had femoral and soft tissue; and 42 children (27.3%) had pelvic, femoral, and soft tissue procedures. Using the Bucholz and Ogden or the Kalamchi classifications, the rate of avascular necrosis was 24.7% (38/154). Of the variables evaluated, preoperative Reimers was found to be significant predictors of avascular necrosis. The rate of avascular necrosis was 26.7% for Gross Motor Functional Classification System level III, 24.1% for Gross Motor Functional Classification System level IV, and 27.3% for Gross Motor Functional Classification System level V.Conclusion:The overall rate of avascular necrosis in children undergoing hip containment surgery was 26.7%. Together, age at surgery, open reduction, previous surgery, preoperative Reimers, and estimated blood loss contributed to the development of postoperative avascular necrosis; however, only preoperative Reimers significantly contributed to the development of avascular necrosis in children with cerebral palsy undergoing hip containment procedures.     

Comparison of caudal block using bupivacaine and ketamine with ilioinguinal nerve block for orchidopexy in children

Forty boys weighing less than 25 kg undergoing unilateral orchidopexy were randomly allocated to receive one of two analgesic regimens. Group C received a caudal epidural block with 0.25% bupivacaine 1 mlkg⁻¹ and preservative-free ketamine 0.5 mgkg⁻¹; Group L received an ilioinguinal nerve block with 0.25% bupivacaine 0.5 mlkg⁻¹ and infiltration of the wound with 0.25% bupivacaine 0.5 mlkg⁻¹. All subjects received diclofenac sodium 1–2 mgkg⁻¹ as a rectal suppository. Postoperative pain was assessed by means of a modified Objective Pain Score and analgesia was administered if this exceeded a value of 4. The median duration of analgesia was 10 h (range 2.6 to > 24 h) in Group C and 2.9 h (range 0.7 to > 24 h) in Group L (p < 0.05). There were no differences between groups in the incidence of motor block, urinary retention, postoperative vomiting or postoperative sedation. Subjects in Group L required significantly more doses of postoperative analgesia than those in Group C (p < 0.05).     

The efficacy of caudal morphine or bupivacaine combined with general anesthesia on postoperative pain and neuroendocrine stress response in children

BACKGROUND: The aim of this study was to compare the effectiveness of caudal morphine and bupivacaine usage on surgical stress response in children undergoing abdominal and genitourinary surgery while keeping anesthesia depth constant utilizing the bispectral index analysis (BIS). METHODS: Following the approval of Institutional Review Board and informed parental consent, 28 children with ages ranging between 4 and 16 years with ASA physical status I and II , undergoing elective lower abdominal and genitourinary surgery were included in this study. Patients were randomized and separated into two subgroups. Before induction of anesthesia, patients were monitored for BIS. Epidural injection of 30 microg.kg(-1) morphine in 1 ml.kg(-1) saline for the first group (group M) and the same volume of (0.25%) bupivacaine for second group (group B) were administered via the sacral hiatus. We analyzed serum cortisol and glucose concentrations for evaluation of the stress response in the patients. Blood samples for cortisol and glucose were withdrawn at the beginning of induction (first samples), 40 min after surgical incision (second samples), and 40 min after end of the surgery (third samples). BIS scores of the patients were kept between 40 and 60 during the surgical procedure. RESULTS: Group B had significantly lower levels of cortisol than group M in the second samples. There was a significant increase in serum glucose level in group M compared with group B during the intraoperative and postoperative periods. CONCLUSIONS: We conclude that, caudal administration of bupivacaine is more effective than morphine for attenuating intraoperative and postoperative stress response to surgery in children.     

Effect of ilioinguinal nerve block on the catecholamine plasma levels in orchidopexy: comparison with caudal epidural block

BACKGROUND: Both caudal epidural and ilioinguinal/iliohypogastric nerve blocks have been used to provide effective intra- and postoperative analgesia. Stress response hormone levels can be used as an objective method to assess the analgesic efficacy of the anaesthetic techniques used in infraumbilical surgery in children. In this study, we compared catecholamine blood levels in children undergoing these two different supplementary analgesic/anaesthetic techniques. METHODS: Thirty male paediatric patients undergoing orchidopexy, ASA I, received inhalation general anaesthesia, and were randomly allocated to one of two groups: a caudal group (n = 15) and an ilioinguinal/iliohypogastric nerve block group (n = 15). Plasma epinephrine and norepinephrine concentrations were measured at the induction time, at the end of surgery, and in the postanaesthesia care unit. Postoperative pain score was also assessed in the postanaesthesia care unit. Results: In both groups, there was a substantial decrease in the catecholamine blood levels; however, there were significantly higher levels of epinephrine in the ilioinguinal group at the end of surgery (P = 0.008) and in the recovery room (P = 0.02) and a significant higher level of norpinephrine in the recovery room (P = 0.008). CONCLUSIONS: The result of this study revealed that caudal epidural block was more effective than ilioinguinal block in suppressing the stress response as reflected in epinephrine and norepinephrine blood levels in orchidopexy patients.     

Single-stage multilevel soft-tissue surgery in the lower limbs with spastic cerebral palsy: Experience from a rehabilitation unit

Background:

To assess the effect of single-stage multilevel soft-tissue surgery (Single Event Multiple Level Resections, SEMLR) on deformities and locomotion in patients with cerebral palsy (CP) with static contracture(s) in lower limbs.

Patients and Methods:

Study included 34 patients (M:F, 23:11) with mean age of 9.53 ± 3.92 years (4–16 years). Among them 22 had diplegia and four each had quadriplegia and right and left hemiplegia. Fourteen patients (41.2%) had their intelligence quotient (IQ) in the normal range (IQ ≥ 80), while others had mental retardation (MR) of varying severity: borderline MR (IQ = 70–79) in 12, mild MR (IQ = 50–69) in 5, and moderate MR (IQ = 35–49) in patients 3. All patients underwent surgery (total number of procedures 153, average 4.5 procedures/patient) over a period of 30 months (April 2005 to September 2007). Improvement in functional abilities and locomotion was assessed using Gross Motor Functional Classification Scale (GMFCS) scores and by physical examination.

Results:

Significant improvement in function was observed (P = 0.000) after surgery when comparing the preoperative and postoperative GMFCS scores. All patients were maintaining ambulation at a mean follow-up duration of 13.12 ± 6.07 months (3–24 months), with five patients using knee-ankle-foot orthoses (KAFO), 22 using ankle-foot orthoses (AFO), and six patients using knee gaiters. Sixteen patients were using walker, and two were using crutches as assistive devices.

Conclusion:

This study suggests that CP patients with good trunk control and static contractures at multiple joints in the lower limbs can be made ambulant with single-stage multilevel soft-tissue surgery. It has to be a team effort of the surgeon and the rehabilitation team in the postoperative period for the attainment of satisfactory goal.     

Bispectral Index values are higher during halothane vs. sevoflurane anesthesia in children, but not in infants

BACKGROUND: Previously, we have shown in adult patients that bispectral index score (BIS) values are significantly higher during halothane anesthesia (53-61 units) as compared with those observed during equipotent concentrations of sevoflurane (39-43 units). Because halothane is frequently used in the pediatric setting, we tested the hypothesis that BIS values observed in children might also be higher during general anesthesia with halothane than with sevoflurane. METHODS: Forty-one healthy, unpremedicated pediatric patients scheduled for elective operations received either halothane or sevoflurane titrated as appropriate for surgical stimulation. RESULTS: During maintenance sevoflurane anesthesia (n=20), the mean BIS values and percent end-tidal concentrations were 44+/-14 and 2.1+/-0.6, respectively, whereas for the halothane group (n=21) the corresponding values were 61+/-7 and 1.1+/-0.4, respectively. CONCLUSION: These findings suggest that BIS values are higher during halothane vs. sevoflurane anesthesia in children, but not in infants.     

The effects of caudal or intravenous clonidine on postoperative analgesia produced by caudal levobupivacaine in children

Background: Clonidine is used increasingly in pediatric anesthesia practice to prolong the duration of action of caudal block with a local anesthetic agent. Which route of administration of clonidine is the most beneficial remains unknown. We compared the effects of caudal and intravenous clonidine on postoperative analgesia produced by caudal levobupivacaine. Methods: Sixty ASA I and II children, aged 2–8 undergoing inguinal hernia repair or orchidopexy surgery received standardized premedication with midazolam and general anesthesia. The children were randomized in a double‐blind fashion to three groups. Group L (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine and i.v. 5 ml saline, Group L‐Ccau (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine + 2 μg·kg^?1 clonidine and i.v. 5 ml saline, Group L‐Civ (n = 20) patients received 0.75 ml·kg^?1 of caudal 0.25% levobupivacaine and i.v. 2 μg·kg^?1 clonidine in 5 ml of saline. Mean arterial blood pressure, heart rate, peripheral oxygen saturation, and end‐tidal carbon dioxide values were recorded. Postoperative pain [Children and Infants Postoperative Pain Scale (CHIPPS) score], sedation (Ramsay Sedation Scale) and motor blockade (Modified Bromage Scale) were assessed at predetermined time points during the first 24 h after surgery. Results: Caudal clonidine significantly delayed the time to first rescue analgesic and fewer patients required rescue analgesia in the 24 h after surgery. No motor block was observed in any of the three groups on awakening or during the study period. In Group L‐Ccau, the CHIPPS score was lower than in Group L at all times through 240 min (P < 0.05), while the pain scores were lower in Group L‐Civ only at extubation and at 240 min (P < 0.05). Conclusions: Caudal clonidine prolongs the duration of analgesia produced by caudal levobupivacaine without causing significant side effects and this is because of a spinal mode of action.     

The correlation of bispectral index with endtidal sevoflurane concentration and haemodynamic parameters in preschoolers

BACKGROUND: Bispectral index (BIS) is a signal processing device that potentially is a pharmacodynamic measure of the effects of anaesthesia on the central nervous system. METHODS: In this prospective blinded study, we investigated the pharmacodynamic relationship between BIS, haemodynamic changes during anaesthesia and endtidal nonsteady state concentrations of sevoflurane in 30 children, mean age 3.3 +/- 1.1 years, who were undergoing tonsillectomy and adenoidectomy. A standardized anaesthetic technique was used and included induction and maintenance with sevoflurane, nitrous oxide and oxygen. BIS, heart rate, mean arterial pressure (MAP) and endtidal sevoflurane (ETsevo) concentrations were continuously recorded and specifically noted at the time of intubation, placement of Dingman gag, incision of adenoid, adenoid out, incision of tonsil, tonsil one out, tonsil two out, last agent off, first spontaneous movement, first eye opening and extubation. The anaesthetist was blinded to BIS throughout the procedure. RESULTS: Using a Spearman correlation analysis, there was significant negative correlation between BIS and ETsevo concentrations (r=- 0.888, P < 0.01) and a pharmacodynamic relationship with EC50 (ETsevo at which BIS=50) of 1.48% (95% confidence interval 0.84-2.11). There was a weak negative correlation between sevoflurane and MAP (r=- 0.391, P < 0.01) but no significant correlation between sevoflurane and heart rate. CONCLUSIONS: In preschool children undergoing sevoflurane anaesthesia for tonsillectomy and adenoidectomy, endtidal sevoflurane concentrations are more closely correlated with BIS than with MAP or heart rate.