How David Hatch became a professor of pediatric anesthesia.

This is an account of an interview with David John Hatch who was one of the first Professors of Pediatric Anesthesia in the world. He began his anesthesia career as a medical student administering chloroform and ended it 40 years later as a Consultant at Great Ormond Street Hospital where he developed and led a world renowned research team measuring and assessing lung function in infants and children. These productive years earned him his chair at the Institute of Child Health in London (part of University College London) funded by Portex (currently, a branch of Smiths Medical). His academic achievements include over 110 journal publications, two textbooks and having many honors and awards. Yet he does not think of himself as an academic. In his words "I wanted to be a hard working clinician with an interest in research, and not just academic".

Perioperative experiences of anesthesia reported by children and parents.

BACKGROUND: The Sprint National Anaesthesia Project reported feedback from adults but not from children. We developed questionnaires for children and parents, and conducted a survey of perioperative anesthetic experiences in a large pediatric hospital. METHODS: Patients undergoing elective general anesthesia were selected randomly each weekday over 10 weeks. Parents and children were approached within 4 hours after awakening, and were asked to complete a short questionnaire. Personal or patient identifiable data were not collected. Questionnaires were processed by optical mark reading technology and descriptive data analysis was performed. RESULTS: Seven hundred and forty parents and 250 children completed questionnaires. The most common symptoms reported by parents were thirst and hunger (76%), drowsiness (75%), sore throat (41%), and pain of the surgery (38%). Sixty-four percent of children felt worried or scared about something before the procedure: common worries were about the "anesthetic," "procedure," or "needles/cannula." Fifty-five percent reported postoperative pain. Thirty-nine children (15.6%) remembered something between going to sleep and waking up although distress was not reported; of these, the most common experiences remembered included hearing voices (34%), feeling sore (20%), and being worried (14%). Twenty-two parents (2.9%) had any complaint and most were about fasting instructions. Only 3 parents would not recommend the anesthetic service. CONCLUSION: This study shows that the experiences of children and their parents are similar to those of adults reported by the Sprint National Anaesthesia Project. Thirst (and hunger), anxiety, and pain continue to be common problems for many children. This feedback may help direct interventions and research to improve the pediatric patient and parent experience with anesthesia.

Three-Dimensional Imaging-Based Web Application for Predicting Tracheal Tube Depth in Preterm Neonates.

BACKGROUND: Positioning a tracheal tube (TT) to the correct depth in preterm infants is challenging. Currently, there is no reliable single-predictor model for neonates applicable to the whole range of size or age. OBJECTIVE: In this study, we used post-mortem magnetic resonance imaging (PMMRI) of preterm infants to measure tracheal dimensions and to develop a clinical guide for TT positioning. METHODS: We measured tracheal length (TL) and tracheal diameter (TD) in a cohort of normal neonates and foetuses that underwent PMMRI (cause of death unexplained). The distance between the lips and the mid-tracheal point, i.e., the mid-tracheal length (mid-TL), and the TD measurement were obtained. We produced univariate prediction models of mid-TL and TD, using gestational age (GA), foot length (FL), crown-rump length (CRL) and body weight (BW) as potential predictors, as well as multiple prediction models for mid-TL. RESULTS: Tracheal measurements were performed in 117 cases, with a mean GA of 28.8 weeks (range 14-42 weeks). The best linear association was between mid-TL and FL (mid-TL = FL × 0.914 + 1.859; R2 = 0.94), but was improved by multivariate regression models. We developed a prediction tool using only GA and BW (R2 = 0.92), and all four predictors (GA, BW, FL and CRL; R2 = 0.94) which is now available as a web-based application via the Internet. CONCLUSION: Post-mortem imaging data provide estimates of TT insertion depth. Our prediction tool based on age and BW can be used at the bedside and is ready to be tested in clinical practice.

The State of UK Dental Anaesthesia: Results From The NAP5 Activity Survey. A national survey by the 5th National Audit Project of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland.

The National Health Service anaesthesia annual activity (2013) was recently reported by the Fifth National Audit Program of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland. Within a large dataset were 620 dental cases. Here, we describe this data subset. The estimated annual dental caseload was 111,600:60% were children (< 16 y), 38.5% adults (16 - 65y) and 1.5% the elderly (> 65y). Almost all were elective day procedures (97%) and ASA 1 or 2 patients (95%).The most senior anaesthetist present was a Consultant in 82% and a non-career grade doctor in 14%.Virtually all (98%) cases were conducted during GA. Propofol was used to induce anaesthesia in almost all adults compared with 60% of children. Propofol maintenance was used in 5% of both children and adults. Almost all adults received an opioid (including remifentanil) compared with only 40% of children. Thirty one per cent of children had a GA for a dental procedure without either opioid or LA supplementation. Approximately 50% of adults and 16% of children received a tracheal tube: 20% of children needed only anaesthesia by face mask. These data show that anaesthetists almost always use general anaesthesia for dental procedures and this exposes difficulties in training of anaesthetists in sedation techniques. Dentists, however, are well known to use sedation when operating alone and our report provides encouragement for a comprehensive survey of dental sedation and anaesthesia practice in both NHS and non-NHS hospitals and clinics in the UK.

Accidental awareness during anesthesia in children.

This educational review explores the current understanding of accidental awareness during general anesthesia (AAGA) in children. Estimates of incidence in children vary between 1 in 135 (determined by direct questioning) and 1 in 51,500 (determined from spontaneous reporting). The lessons from the 5th National Audit Project of the Royal College of Anaesthetists and the Association of Anaesthetists of Great Britain and Ireland show that the characteristics of spontaneous reports of AAGA are extremely variable and relate to the type of procedure and anesthetic technique rather than age group: approximately 50% of experiences were distressing; most lasted less than 5 min; neuromuscular blockade (NMB) combined with pain caused the most distress; most cases (approximately 70%) occur at induction or emergence. The value of depth of anesthesia monitoring in preventing AAGA is uncertain but is probably useful in patients having total intravenous anesthesia and NMB. Reports of AAGA by children should be received sympathetically and a generic protocol for managing distressed patients is presented.

The state of UK pediatric anesthesia: a survey of National Health Service activity.

This secondary analysis of the 2013 United Kingdom National Health Service (NHS) Anaesthesia Activity Survey of the Fifth National Audit Project (of the Royal College of Anaesthetists and Association of Anaesthetists of Great Britain and Ireland) shows pediatric anesthesia activity in detail. A local coordinator (LC) in every NHS hospital collected data on patients undergoing any procedure managed by an anesthetist. Questionnaires had 30 question categories. Each LC was randomized to a 2-day period. The pediatric age groups were infants, (<1 year), preschool age (1-5 year), and school age children (6-15 year). The median questionnaire return rate was 98%. The annual caseload was estimated to be 486 900 children: 36 500 infants, 184 700 preschool age, and 265 800 school age children. Almost 90% of children (1-15 year) were ASA 1 or 2 and the substantial majority underwent routine nonurgent ear nose and throat, dental, orthopaedics, or general surgery procedures; 65% were 'day cases'. One in six children were managed outside operating theater sites compared with one in 12 adults. Forty one per cent was in district general hospitals. Almost all ASA 4 and 5 children (89%) and infants (92%) were managed in specialist hospitals. 'Awake' cases and sedation accounted for only 2% of cases. There were notable differences in demography and anesthetic care compared with adults and between different age groups of children. These data enable analysis of the current state of UK pediatric anesthetic practice and highlight differences between pediatric and adult services.

Measured versus predicted blood propofol concentrations in children during scoliosis surgery.

BACKGROUND: Propofol anesthesia is preferred during scoliosis surgery because it suppresses evoked potential spinal cord function less than other drugs and better enables the detection of spinal cord ischemia. In this study, we determined the difference between the true and predicted blood propofol levels during target-controlled infusions in children during scoliosis surgery. METHODS: Arterial blood propofol measured concentrations (Cm) were compared with predicted concentrations (Cp) approximately every 30 minutes during the maintenance phase of anesthesia in 20 children. Whole blood propofol concentrations were measured using a point-of-care blood propofol analyzer. Anesthesia management was not affected by the study. The median performance error, median absolute performance error, wobble, and divergence were calculated. RESULTS: Children were aged 9 to 17 years and weighed 26.5 to 95 kg. The Paedfusor model was used in 16 children and the Marsh model in 4 children. In 154 blood propofol measurements, the mean difference between the Cm and Cp was 1.5 µg·mL (limits of agreement, -1.4 to 4.5 µg·mL), and the mean performance error was 44.7% (limits of agreement, -40.1% to 130.2%). The median performance error and median absolute performance error for the whole group were 39.8% (range, -20.9% to 103.3%) and 39.8% (range, 20%-103.3%), respectively. The performance errors improved with increase in duration of infusion (divergence, -2.2 [range, -1.03 to 0.13]). Cm was almost always larger than Cp except in 2 children who had consistently lower Cm than Cp (lowest Cm(s) were 1.74 and 1.96 µg·mL when the Cp was 3 µg·mL); both had the Paedfusor model and their body weights were 28 and 33 kg. CONCLUSIONS: Propofol target-controlled infusion models had poor performance characteristics in children undergoing scoliosis surgery. Point-of-care propofol assay may enable adjustment of the infusion to better achieve the intended blood level.

Defining awakening from anesthesia in neonates: a consensus study.

BACKGROUND: A descriptive tool for determining awakening in infants is desirable to test the value of depth of anesthesia monitors. Although scales and criteria have been developed for children and infants, none has been applied to the study of anesthetised neonates. We aimed to seek consensus in a group of experts on a definition of awakening at the end of anesthesia in neonates. METHODS: We used a modified Delphi technique with an iterative process of questionnaires and anonymised feedback. Communication was conducted by email. Thirty-one consultant pediatric anesthetists in the UK and Ireland took part. Consensus was defined a priori as 80% agreement. RESULTS: The 83% of respondents agreed that defining awakening is possible. Consensus was reached on six criteria and also that a combination of these criteria must be used. As crying and attempting to cry are similar, we propose that at least two of the following five behaviors are present to consider a neonate awake after anesthesia: (i) crying or attempting to cry, (ii) vigorous limb movements, (iii) gagging on a tracheal tube, (iv) eyes open, and (v) looking around. There was also consensus that three stimuli are appropriate to test rousability in neonates awakening from anesthesia: (i) removal of skin adhesive tape, (ii) stroking/tickling the skin or gentle shaking, and (iii) pharyngeal suction. CONCLUSIONS: We propose a scale for determining awakening from anesthesia in neonates that may be used in future studies, particularly regarding electroencephalographic data and depth of anesthesia monitoring in neonates.

Defining awakening from anesthesia in infants: a narrative review of published descriptions and scales of behavior.

OBJECTIVES: A descriptive tool or validated scale of consciousness is desirable in infants to test the value of any depth of anesthesia monitor. METHODS: We have reviewed published descriptions and scales of observed behavior that may be applicable to the study of infants during the transition from anesthesia to wakefulness. RESULTS: Potentially useful scales were found that had been developed for the assessment and study of natural sleep, neurological state, arousal, anesthesia, sedation, coma, and pain. Scales or criteria of behavior had been developed for anesthetised children, but there were no agreed definitions or criteria specifically for anesthetised infants or neonates. CONCLUSION: Criteria for awakening of infants from anesthesia need to be developed and agreed.

Water-filled garment warming of infants undergoing open abdominal or thoracic surgery.

We have assessed the efficacy of a water-filled garment (ThermoWrap-Allon 2001) to maintain normothermia in small infants during major open abdominal or thoracic surgery. Twenty-two patients were studied in a case-matched comparison of two methods of thermal control intended to maintain core body temperature at 37 degrees C. The standard method involved a warm air mattress with additional insulation. The ThermoWrap garment covered the head, trunk and legs and the water temperature was automatically controlled. Central and peripheral temperatures were recorded every 15 min. Nineteen infants had abdominal and three had thoracic operations. The mean weight was 3.2 kg (range 1.4-7.8 kg). Over time, the core temperature declined with standard care but not with the ThermoWrap. Core temperature was statistically lower in the standard care infants by 30 min after start of surgery. Six infants had a core temperature of less than 35 degrees C with standard care (lowest 33.7 degrees C); the lowest temperature with the ThermoWrap was 35.6 degrees C. Some infants had cold hands with the ThermoWrap. Core temperature is better preserved with the ThermoWrap; extra insulation of exposed arms may be necessary. An important advantage of the ThermoWrap is its ability to control body temperature automatically.

Recovery after anesthesia for short pediatric oncology procedures: propofol and remifentanil compared with propofol, nitrous oxide, and sevoflurane.

Anesthesia techniques in children undergoing short painful oncology procedures should allow rapid recovery without side effects. We compared the recovery characteristics of two anesthetic techniques: propofol with sevoflurane and nitrous oxide and a total IV technique using propofol and remifentanil. Twenty-one children, undergoing two similar painful procedures within 2 wk were studied in a single-blind manner within patient comparison. The order of the techniques was randomized. Propofol and remifentanil involved bolus doses of both propofol 3-5 mg/kg and remifentanil 1-4 microg/kg. Propofol with sevoflurane and nitrous oxide involved propofol 3-5 mg/kg with 2%-8% sevoflurane and 70% nitrous oxide. The primary outcome variable was the time taken to achieve recovery discharge criteria; other recovery characteristics were also noted. The mean age of the children was 6.5 yr (range, 2.5-9.8 yr). Nineteen had lymphoblastic leukemia and two had lymphoma. All children had intrathecal chemotherapy and one had bone marrow aspiration. Most procedures lasted <4 min. The mean time to achieve recovery discharge criteria was appreciably shorter after propofol and remifentanil than propofol with sevoflurane and nitrous oxide by nearly 19 min (P = 0.001). All other time comparisons had similar trends and statistical differences. Seven parents expressed a preference for the propofol and remifentanil technique compared with one preferring propofol with sevoflurane and nitrous oxide. Children are apneic during the procedure and require respiratory support from an anesthesiologist. Discharge readiness from the recovery ward was achieved on average 19 min earlier after propofol with remifentanil compared with the combination of propofol, sevoflurane and nitrous oxide. Parents more often preferred propofol with remifentanil.

Sevoflurane sedation in infants undergoing MRI: a preliminary report.

BACKGROUND: Stillness during natural sleep after feeding may not be sufficient for successful magnetic resonance imaging (MRI) in small infants less than 5 kg. Sedation, using an oral agent, is often successful although the timing and depth of sedation is variable. In contrast anesthesia is always effective but is invasive and is associated with postanesthesia apnea and bradycardia in preterm and ex-preterm infants. We are developing an alternative technique involving insufflation of sevoflurane and present our initial experience. METHODS: Infants presenting for MRI were sedated by nasal insufflation of sevoflurane carried by 2 l.min(-1) oxygen. We recorded the sevoflurane administered, timing of sedation and scanning, conscious level, oxygen saturations, and recovery profile. RESULTS: Of the 13 infants studied (median postconceptional age: 46 weeks, range: 40-70 weeks; median weight: 4.4 kg, range: 3.3-6.5 kg), sevoflurane caused sleep and enabled successful imaging in 12. Six infants fell asleep within 10 min and the median maximum sevoflurane vaporizer setting for successful sedation was 4% (range: 4-8%). Before scanning, 10 infants remained easily roused by touch and two became unresponsive; one desaturated to 85% and required repositioning of the head to maintain a clear airway. Immediately after scanning all infants were easily roused by touch. CONCLUSIONS: Sedation by insufflation of sevoflurane in small infants is a simple and practical alternative technique for painless imaging such as MRI; further experience is necessary to determine its limitations.