The mucopolysaccharidoses (MPS) are well known to present a high risk of anesthesia. Predominantly, this risk is not only related to upper airway issues but also to multilevel airway obstruction, respiratory morbidity, and cardiac issues. Before disease-specific treatment became available, the management of the untreated patients with MPS was regarded as the worst airway problem in pediatric anesthetic practice. The last 20 to 30 years have seen great advances in the treatment of the different types of MPS with hematopoietic stem cell transplantation (HSCT) being offered to children with MPS I Hurler sundrome since the 1980s, and more recently enzyme replacement therapy (ERT) becoming available for many MPS subtypes. These treatments have undoubtedly affected the relative risk involved with an anesthetic. HSCT improves markedly the upper airway and cardiac myocardial function and there is evidence that airway management is much more straightforward. ERT, on the other hand, improves obstructive sleep apnea and exercise tolerance, but the overall effect on the risk of anesthesia is less obvious and airway complications during anesthesia remain at a high level. The impact of improved anesthetic management in the same time frame is borne out by a reduced failed intubation rate in the literature. The management of the MPS patients necessitates a multidisciplinary approach presently widely practiced in pediatric centers, but successful modes of therapy increasing their life span have pushed many of the extreme anesthetic challenges into adult practice where most anesthetists will be unfamiliar with the problem. This is a problem that needs to be addressed, and solutions to this issue could be collaborative working between pediatric and adult practitioners or an international network of experts available for advice.

This Invited Commentary accompanies the following original article: Koers L, Janjatovic D, Stevens MF, Preckel B. The emergency paediatric surgical airway. A systematic review. Eur J Anaesthesiol 2018; 35:558–565. Morbidity and mortality in children is closely matched to difficulties in airway management and has been reported persistently over the years.1 The perceived 'safety net' of 'front of neck access' to salvage a desperate situation remains engrained in the psyche of the attending clinician. There is, however, very little evidence to support this attitude in small children. The article by Koers et al.2 in this month's issue of the European Journal of Anaesthesiology aims to add evidence to the subject of 'front of neck access' in paediatric practice, by critically evaluating preclinical animal studies performed with either a needle-based or a scalpel-based technique. More specifically, this review only analyses the success of the techniques to gain access to the trachea. It does not address the ability to oxygenate, or indeed to ventilate, following successful needle cannulation or access with a surgical technique. Fortunately, extreme difficulties with airway management in children are rare and can usually be anticipated. Paediatric airway management is easy in experienced hands in a suitable environment. However, many children are anaesthetised in nonspecialist centres by anaesthetists without regular paediatric practice who may find the 'normal' airways of young children difficult to manage. Therefore, the fact remains that healthy children experience a disproportionate morbidity burden in the peri-operative period due to airway management problems.3 However, this morbidity can be easily prevented by following simple, locally adaptable algorithms which should include the recognition and treatment of anatomical/mechanical and functional airway obstructions, and recommendations on limiting intubation attempts.1,4 Following such an algorithm should negate the need for an emergency front of neck access in the otherwise healthy child. On the contrary, functional airway obstructions, the most common reason for a 'cannot ventilate' situation in children are not, or only insufficiently, addressed in paediatric airway algorithms or mainstream paediatric anaesthesia text books. The commonly used term 'cannot intubate, cannot oxygenate' implies that endotracheal intubation or front of neck access has a higher priority than the recognition and treatment of 'simple' oxygenation and ventilation problems, and very little attention is given to the role of respiratory reserves in small children.4 Children with significant comorbidities and difficult acquired or congenital airway problems will benefit from the expert care of a trained practitioner in a suitably staffed and supported environment. However, there will be situations in which an unplanned emergency front of neck access is the only chance of survival. These are exceedingly rare – 'a once in a lifetime event' – without any data on its actual frequency and no clinical data in children to guide management. The ultimate choice (apart from the unlikely timely presence of a skilled rigid bronchoscopist) is between a surgical access and a needle technique. Both techniques carry risks of complications and failure, so one must choose the technique with fewest downsides, but it should be remembered that muscle relaxation is strongly recommended in any age group before attempting such a procedure.5 The systematic review by Koers et al.2 summarises the options which are based on clinical case scenarios and animal models. They included studies that had specific outcome criteria, including time to tracheal access, success rate, complications and perceived ease of use. The results show that for a specialised needle-based technique, which is also recommended in the Association of Paediatric Anaesthetists of Great Britain and Ireland (APAGBI)/Difficult Airway Society (DAS) 2011 guideline,6 the time to tracheal access via the cricothyroid membrane is faster and has a success rate of around 100%.7 This simulated success rate, however, is in complete contrast to the actual reported success rate in adults, with only nine of 25 attempts successful when performed in emergency situations: systematic paediatric data unavailable.5 This uncertainty is further exacerbated when considering the different neck anatomy and compressibility of the airway in childen.8 Airway dimensions are also critical when accessing the front of the neck. The dimensions of the cricothyroid membrane in neonates were measured at 2.6 ± (SD) 0.7 mm in height by 3 ± 0.63 mm in width compared with 9 to 10 mm in adults.9 This makes insertion of an adequately sized tracheal tube through the cricothyroid membrane impossible. A surgical technique on the other hand, is slower, still has a complication rate of around 40%, but is successful in nearly nine out of 10 interventions under laboratory conditions using nonhuman, nonpaediatric models and tissues. A surgical technique, however, also allows direct access to tracheal structures which would accommodate available age appropriate endotracheal tubes, inserted either directly, via a bougie or another guide (wire). We should note that this surgical technique was not designed with the paediatric population in mind, but is increasingly popular amongst nonpaediatric anaesthesiologists. It is also consistent with changing attitude amongst paediatric anaesthetists over which technique to use in emergency front of neck access. A recent survey of the members of the APAGBI10 revealed an increasing number favouring a surgical technique especially in over 1 year olds (52%) and over 8 year olds (73%). We urgently need evidence on what really works for different age groups. Therefore, at this point, we would like to call for the setup of a suitable paediatric airway registry to capture the success and failures of difficult airway management and front of neck access. Ideally, this registry should be compatible with already existing registries that, due to existing data protection laws, are not globally accessible. 'Safe Haven' analyses of pooled compatible data are the only realistic option to inform this emotional debate with hard data. European and other national societies have a duty to support such projects to research these rare but very important decisions. However, this important data may take some years to collect and, in the meantime, we must continue to evaluate different techniques of gaining emergency access to the trachea, in all ages of children. We must continue to look at the needle approach but also look seriously at surgical techniques which could be taught to the paediatric anaesthetic community. Most importantly, however, we must continue to focus on the need to prevent emergency front of neck access by implementing the teaching and training of reasonably simple, straightforward paediatric airway algorithms. Acknowledgements relating to this article Assistance with the Invited Commentary: none. Financial support and sponsorship: none. Conflicts of interest: none. Comment from the Editor: this article was checked and accepted by the Editors, but was not sent for external peer-review.

The current guidelines for preoperative fasting recommend intervals of 6, 4, and 2 h (6-4-2) of fasting for solids, breast milk, and clear fluids, respectively. The objective is to minimize the risk of pulmonary aspiration of gastric contents, but also to prevent unnecessarily long fasting intervals. Pulmonary aspiration is rare and associated with nearly no mortality in paediatric anaesthesia. The incidence may have decreased during the last decades, judging from several audits published recently. However, several reports of very long fasting intervals have also been published, in spite of the implementation of the 6-4-2 fasting regimens. In this review, we examine the physiological basis for various fasting recommendations, the temporal relationship between fluid intake and residual gastric content, and the pathophysiological effects of preoperative fasting, and review recent publications of various attempts to reduce the incidence of prolonged fasting in children. The pros and cons of the current guidelines will be addressed, and possible strategies for a future revision will be suggested.

Recent studies have reported perioperative pulmonary aspiration in pediatric practice to be an uncommon problem associated with low morbidity and mortality. This paper examines the recent publications in both the adult and pediatric literature and looks at some of the potential risk factors involved, both patient and anesthetic, in the development of aspiration of gastric contents. We also look at the risk of severe morbidity following pulmonary aspiration and speculate on possible reasons behind the assertion that pulmonary aspiration in pediatric anesthetic practice is rare and a low-risk event.

Background Pulmonary aspiration of gastric contents is a potentially devastating complication of anesthesia.Aims This prospective multicenter survey of specialist pediatric centers in the UK set out to elucidate the incidence, risk factors, and the outcome of such events. The survey took place over a twelve-month period via a web-based secure reporting system.Results Over the twelve-month period, 24 cases of pulmonary aspiration were reported. Over that time period, there were 118371 cases performed at the eleven pediatric centers. The overall incidence of pulmonary aspiration is therefore 1 in 4932 cases or 2 in 10000 cases. Over that time period, there were 18 cases during elective surgery and six cases in nonelective/emergency surgery. The incidence of pulmonary aspiration in the elective situation is therefore 1 in 5076 cases or 2.0 per 10000 cases. The incidence in emergency procedures is 1 in 4498 cases or 2.2 per 10000 cases. The timing and severity of deterioration were recorded. In the study period, 8 of 24 cases did not deteriorate, 13 of 24 deteriorated with immediate effect, and the further 3 of 24 deteriorated within the next hour. The deterioration was mild in 11 patients requiring medical management only, and the deterioration was severe in five patients. Those five patients required ventilation for varying durations of time. All patients made a full recovery.Conclusions This multicenter survey of specialist pediatric centers in the UK over a one-year period reveals a low incidence of pulmonary aspiration in both elective and emergency cases. All patients made a full recovery.

This paper provides a detailed overview and discussion of anaesthesia in patients with mucopolysaccharidosis (MPS), the evaluation of risk factors in these patients and their anaesthetic management, including emergency airway issues. MPS represents a group of rare lysosomal storage disorders associated with an array of clinical manifestations. The high prevalence of airway obstruction and restrictive pulmonary disease in combination with cardiovascular manifestations poses a high anaesthetic risk to these patients. Typical anaesthetic problems include airway obstruction after induction or extubation, intubation difficulties or failure [can't intubate, can't ventilate (CICV)], possible emergency tracheostomy and cardiovascular and cervical spine issues. Because of the high anaesthetic risk, the benefits of a procedure in patients with MPS should always be balanced against the associated risks. Therefore, careful evaluation of anaesthetic risk factors should be made before the procedure, involving evaluation of airways and cardiorespiratory and cervical spine problems. In addition, information on the specific type of MPS, prior history of anaesthesia, presence of cervical instability and range of motion of the temporomandibular joint are important and may be pivotal to prevent complications during anaesthesia. Knowledge of these risk factors allows the anaesthetist to anticipate potential problems that may arise during or after the procedure. Anaesthesia in MPS patients should be preferably done by an experienced (paediatric) anaesthetist, supported by a multidisciplinary team (ear, nose, throat surgeon and intensive care team), with access to all necessary equipment and support.

Objective: Patients with mucopolysaccharidosis type II (MPS II) may develop progressive multi-level upper airway obstruction. Despite the unique challenges presented by these complex patients, tracheostomy remains an important intervention to safeguard the airway when other interventions have failed or when the airway obstruction involves multiple sites. Airway involvement is largely responsible for the significant anaesthetic risk seen in MPS II. We reviewed our tertiary unit's experience of tracheostomies in patients with MPS II.Study design: Retrospective study.Methods: Case note review of MPS II patients requiring tracheostomy at our tertiary institution. The primary outcome measure used for this study was complications following tracheostomy.Results: We identified 10 MPS II patients requiring tracheostomy to manage upper airway obstruction. Mean age at which tracheostomy was 11 years 2 months (range 4 years 6 months to 28 years 10 months). Tracheostomy insertion was indicated in 3 scenarios: (1) to safeguard an anticipated difficult airway prior to a planned non-ENT surgical procedure, (2) to treat refractory progressive upper airway obstruction and (3) emergency airway management. Complications recorded included infratip and suprastomal granulations, local wound infection and skin ulceration from mechanical trauma. There were no immediate postoperative complications.Conclusions: Progressive upper airway obstruction is common in children with MPS II. Tracheostomy is an effective way of managing airway obstruction when less invasive interventions are no longer adequate. Tracheostomy in these patients can be technically difficult and although the complications of tracheostomy in MPS II do not significantly differ from other patient groups, the implications and management complexity vary considerably. The impact of ERT on airway obstruction is not yet fully understood, with tracheostomies likely to remain an important airway adjunct in some patients who fail to respond to ERT, or in those patients surviving into adulthood. It is vital that a multidisciplinary team, comprising clinicians with experience in managing such patients, are involved in airway management of patients with MPS II to enable the best standard of care to be given. The significant additional implications of a tracheostomy in a patient with MPS II, in terms of safety, aftercare and potentially life-threatening complications must be discussed in detail with the patient's family and/or carers. (c). 2013 Elsevier Ireland Ltd. All rights reserved.

AIM:To assess the effect of bone marrow transplantation (BMT), enzyme replacement therapy (ERT), and a fiberoptic endotracheal intubation technique in patients with mucopolysaccharidosis type I (MPS I, Hurler syndrome).BACKGROUND:The mucopolysaccharidoses are inherited metabolic conditions with a well-documented association with difficult airway management. We present the largest series to date of patients with Hurler syndrome (MPS I) and look at the impact of new treatments, such as BMT and ERT, on anesthesia and airway management.METHODS/MATERIALS:We carried out a retrospective chart review of patients with MPSI undergoing anesthesia over 9 years at the Royal Manchester Children's Hospital. Data were collected on incidence of difficult and failed intubation and airway difficulties under anesthesia.RESULTS:There were 39 patients identified, of which 20 had the attenuated form of MPS I and received ERT, 18 were treated by BMT and one patient received neither treatment. These patients had a total of 114 general anesthetics for 141 procedures. The incidence of airway complications overall is lower than previously reported at 31%. Patients with the attenuated form of the disease on ERT still have a high incidence of airway problems at 57% and a failed intubation rate of 3%. BMT patients on the other hand have a much lower incidence of airway complications at 14%, and there were no failed intubations in this group.CONCLUSIONS:Managing the MPS1 patient continues to be a challenge but with treatment and newer forms of airway management it is improving.

Pediatric AnesthesiaVolume 21, Issue 2 p. 169-169 Not all laryngeal masks are the same for difficult airway work Rosalind Morley, Rosalind Morley Royal Manchester Children’s Hospital,Manchester, UK(email: [email protected])Search for more papers by this authorRobert Walker, Robert Walker Royal Manchester Children’s Hospital,Manchester, UK(email: [email protected])Search for more papers by this author Rosalind Morley, Rosalind Morley Royal Manchester Children’s Hospital,Manchester, UK(email: [email protected])Search for more papers by this authorRobert Walker, Robert Walker Royal Manchester Children’s Hospital,Manchester, UK(email: [email protected])Search for more papers by this author First published: 06 January 2011 https://doi.org/10.1111/j.1460-9592.2010.03481.xRead the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. References 1 Baker PA, Brunette KEJ, Byrnes CA et al. A prospective randomised trial comparing supraglottic airways for flexible bronchoscopy in children. Pediatr Anesth 2010; 20: 831– 838. 2 Walker RWM. The laryngeal mask airway in the difficult paediatric airway: an assessment of positioning and use in fibreoptic intubation. Paediatr Anaesth 2000; 10: 53– 58. Volume21, Issue2February 2011Pages 169-169 ReferencesRelatedInformation

Mucopolysaccharidosis type II (MPS II) is a rare, life-limiting, X-linked recessive disease characterised by deficiency of the lysosomal enzyme iduronate-2-sulfatase. Consequent accumulation of glycosaminoglycans leads to pathological changes in multiple body systems. Age at onset, signs and symptoms, and disease progression are heterogeneous, and patients may present with many different manifestations to a wide range of specialists. Expertise in diagnosing and managing MPS II varies widely between countries, and substantial delays between disease onset and diagnosis can occur. In recent years, disease-specific treatments such as enzyme replacement therapy and stem cell transplantation have helped to address the underlying enzyme deficiency in patients with MPS II. However, the multisystem nature of this disorder and the irreversibility of some manifestations mean that most patients require substantial medical support from many different specialists, even if they are receiving treatment. This article presents an overview of how to recognise, diagnose, and care for patients with MPS II. Particular focus is given to the multidisciplinary nature of patient management, which requires input from paediatricians, specialist nurses, otorhinolaryngologists, orthopaedic surgeons, ophthalmologists, cardiologists, pneumologists, anaesthesiologists, neurologists, physiotherapists, occupational therapists, speech therapists, psychologists, social workers, homecare companies and patient societies.

This article looks at the current techniques and equipment recommended for the management of the difficult intubation scenario in pediatric practice. We discuss the general considerations including preoperative preparation, the preferred anesthetic technique and the use of both rigid laryngoscopic and fiberoptic techniques for intubation. The unanticipated scenario is also discussed.

Pediatric AnesthesiaVolume 18, Issue 11 p. 1123-1124 The anesthetic management of a child with infantile systemic hyalinosis Michael Pollard, Michael Pollard Specialist Registrars in Anaesthesia, North West Deanery, UKSearch for more papers by this authorEshan M. Ollite, Eshan M. Ollite Specialist Registrars in Anaesthesia, North West Deanery, UKSearch for more papers by this authorRobert W.M. Walker, Robert W.M. Walker Consultant Anaesthetist, Royal Manchester Children's Hospital, Manchester, UK (email: [email protected])Search for more papers by this author Michael Pollard, Michael Pollard Specialist Registrars in Anaesthesia, North West Deanery, UKSearch for more papers by this authorEshan M. Ollite, Eshan M. Ollite Specialist Registrars in Anaesthesia, North West Deanery, UKSearch for more papers by this authorRobert W.M. Walker, Robert W.M. Walker Consultant Anaesthetist, Royal Manchester Children's Hospital, Manchester, UK (email: [email protected])Search for more papers by this author First published: 06 October 2008 https://doi.org/10.1111/j.1460-9592.2008.02621.xCitations: 7Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. References 1 Felix TM, Puga AC, Cestari T et al. Infantile systemic hyalinosis: report of three unrelated Brazilian children and review of the literature. Clin Dysmorphol 2004; 13: 231– 236. 2 Shin HT, Paller A, Hoganson G et al. Infantile systemic hyalinosis. J Am Acad Dermatol 2004; 50: 61– 64. 3 Vaughn GC, Kaplan RF, Tieche S et al. Juvenile hyaline fibromatosis: anaesthetic management. Anesthesiology 1990; 72: 201– 203. 4 Norman B, Soni N, Madden N. Anaesthesia and juvenile hyaline fibromatosis. Br J Anaesth 1996; 76: 163– 166. 5 Seefelder C, KO JH, Padwa BL. Fibreoptic intubation for massive gingival hyperplasia in juvenile hyaline fibromatosis: a case report. Paediatr Anaesth 2000; 10: 682– 683. Citing Literature Volume18, Issue11November 2008Pages 1123-1124 ReferencesRelatedInformation

Hassid et al. (1) should be commended for highlighting the need for anesthesia ⁄ sedation to facilitate intubation in the neonatal population. Several surveys show that many neonatal intensive care units do not administer any anesthesia ⁄ sedation for this procedure (2,3). Awake intubations may result in other complications as described in their report. I am concerned with the the authors’ use of sevoflurane to facilitate intubation. Sevoflurane is a drug which most non-anesthesiologists are unfamiliar with. It can cause myocardial and respiratory depression, laryngospasm and airway obstruction. MAC for term infants is approximately 3.3%. MAC of sevoflurane has also not been determined in the preterm population but is most likely lower than in term infants. In this study, the patients received 2–5% sevoflurane. Due to their decreased myocardial reserve, neonates are at significant risk to develop hypotension with high concentrations of volatile agents, and it is likely that preterm infants pose an even higher risk. The most recent report of the Pediatric Perioperative Cardiac Arrest (POCA) registry showed sevoflurane, laryngospasm and airway obstruction to be responsible for 3%, 6% and 3% of cardiac arrests respectively (4). The authors conclude that sevoflurane ‘facilitates the conditions for intubation...’ They support this statement by showing a significant difference in lack of movement (95.5% vs 28%) and a lower incidence of bradycardia (8.3 vs 44.4%) in the sevoflurane group. However in spite of better intubating conditions, the intubation failure rate in the study and control groups were not statistically different (25% vs 39%). Any pediatric anesthesiologist would consider such intubation failure rates to be abysmal. The duration of desaturation was also longer in the sevoflurane group although this too was not statistically significant. It is concerning to note that the mean duration of desaturation was 115 s in the sevoflurane group. While I would agree that with the authors that administering sevoflurane may be more humane, their data do not show an improvement in intubation. Moreover, there are inherent risks associated with the use of moderate concentrations of volatile agents in untrained hands in this very fragile population of children. Tetsu Uejima Department of Pediatric Anesthesia, Children’s Memorial Hospital, Children’s Plaza, Chicago, Illinois, USA (email: tuejima@childrensmemorial.org)

Pompe's disease or glycogen storage disease type II is a genetic disorder affecting skeletal and cardiac muscle. The infantile form is associated with gross hypertrophic cardiomegaly and death in the early years. General anesthesia is associated with potential major morbidity in these patients. We present our experience of regional anesthetic blocks used in five patients with the infantile form of glycogen storage disease type II with and without sedation for 11 surgical procedures during a clinical trial of replacement therapy for this condition. Both femoral nerve blockade and caudal epidural blockade were used with good result. The relative merits of the type of block are discussed in addition to the choice of sedation and risks of general anesthesia. The avoidance of general anesthesia in the newly presenting patient with Pompe's disease may reduce potential morbidity until enzyme replacement has been established.

Difficulties with airway management and tracheal intubation occur relatively commonly in infants and children. Minor difficulties due to anatomical and physiological differences between paediatric patients and adults arise frequently; the more severe difficulties are usually associated with specific conditions, some of which are listed in Table 1. Although airway problems may involve pathology in the upper or lower airway, this article deals mainly with problems involving the upper airway and difficult intubation.