Tracheal Resection for Critical Airway Obstruction in Morquio A Syndrome.

Introduction: The primary cause of death in Morquio A syndrome (mucopolysaccharidosis (MPS) IVA) is airway obstruction, brought about by an inexorable and pathognomonic multilevel airway tortuosity, buckling, and obstruction. The relative pathophysiological contributions of an inherent cartilage processing defect versus a mismatch in longitudinal growth between the trachea and the thoracic cage are currently a subject of debate. Enzyme replacement therapy (ERT) and multidisciplinary management continue to improve life expectancy for Morquio A patients by slowing many of the multisystem pathological consequences of the disease but are not as effective at reversing established pathology. An urgent need has developed to consider alternatives to palliation of progressive tracheal obstruction to preserve and maintain these patients' hard-won good quality of life, as well as to facilitate spinal and other required surgery. Case Report. Following multidisciplinary discussion, transcervical tracheal resection with limited manubriectomy was successfully performed, without the need for cardiopulmonary bypass, in an adolescent male on ERT with the severe airway manifestations of Morquio A syndrome. His trachea was found to be under significant compressive forces at surgery. On histology, chondrocyte lacunae appeared enlarged, but intracellular lysosomal staining and extracellular glycosaminoglycan staining was comparable to control trachea. At 12 months, this has resulted in a significant improvement in respiratory and functional status, with corresponding enhancement to his quality of life. Conclusion: This addressing of tracheal/thoracic cage dimension mismatch represents a novel surgical treatment approach to an existing clinical paradigm and may be useful for other carefully selected individuals with MPS IVA. Further work is needed to better understand the role and optimal timing of tracheal resection within this patient cohort so as to individually balance considerable surgical and anaesthetic risks against the potential symptomatic and life expectancy benefits.

Use of Simulation to Visualize Healthcare Worker Exposure to Aerosol in the Operating Room.

SUMMARY STATEMENT: Simulation resources offer an opportunity to highlight aerosol dispersion within the operating room environment. We demonstrate our methodology with a supporting video that can offer operating room teams support in their practical understanding of aerosol exposure and the importance of personal protective equipment.

Retrospective audit of airway management practices in children with craniocervical pathology.

BACKGROUND: Craniocervical immobilization using halo body orthoses may be required in the management of children with craniocervical junction pathology. To date, the effect of such immobilization on perioperative anesthetic management has not been addressed in large series. AIMS: The aim of this study was to review the airway management of children requiring halo body orthoses undergoing general anesthesia. METHODS: The study was a retrospective case note review from a single institution. The neurosurgical database was interrogated to identify all patients less than 16 years of age that required a halo body orthosis from 1996 to 2015. We used the electronic patient record to identify all procedures performed under general anesthesia for these patients, either for halo application, or with the halo in situ. Details of techniques used for airway management were recorded, and paired data between individuals pre- and post-halo application were compared. Demographic data, diagnosis, and perioperative complications were also recorded. RESULTS: We identified 90 children that underwent placement of a halo body orthosis. A total of 269 anesthetic records from these patients were analyzed and classified as pre-halo application, or halo in situ. Facemask ventilation was achieved in all patients, though some required simple airway adjuncts and may have been more difficult in the presence of the halo. Supraglottic airways were used successfully in many patients. There was a significant increase in the number of patients classed as Cormack and Lehane grades 3 or 4 on direct laryngoscopy with the halo in situ compared with before the halo was applied. The incidence of intubation using fiberoptic or videolaryngoscopy was higher with the halo in situ. Multiple intubation attempts were required in 3.4% (1/29) of patients undergoing anesthesia for halo placement compared with 15.1% (11/73) undergoing anesthesia with a halo in situ. CONCLUSION: Airway management in children with cervical spine pathology should be anticipated to be more difficult than the general pediatric population. This is likely to be due to co-existing pathology associated with cervical spine disease in children, limitation of neck movement to prevent further neurological injury, and the halo itself limiting access to the head. We recommend advanced preparation, and ensuring the immediate availability of an anesthetist with skills in managing the pediatric difficult airway to avoid complications in this patient population.

Antiepileptic drugs and anesthesia.

Anesthetists commonly encounter epileptic patients when undergoing surgery. This review article discusses the drugs used to treat epilepsy and their relevant effects on anesthesia.

Anesthesia and epidermolysis bullosa.

Patients with epidermolysis bullosa (EB) may present for anesthesia with an unrelated surgical condition or, more commonly, for diagnostic or therapeutic procedures. Children in particular may require frequent anesthetics. Safe and effective management of anesthesia presents a significant challenge and although there is little rigorous evidence available to aid decision-making, in this article the elements of current good anesthesia care in EB are summarized.

The functional expression of mu opioid receptors on sensory neurons is developmentally regulated; morphine analgesia is less selective in the neonate.

Opioid requirements in neonatal patients are reported to be lower than older infants and this may be a reflection of the developmental regulation of opioid receptors. In this study we have investigated the postnatal regulation of Mu opioid receptor (MOR) function in both rat lumbar dorsal root ganglion (DRG) cultures and behavioural mechanical and thermal reflex tests in rat pups. Immunostaining with MOR and selective neurofilament (NF200) antibodies was combined with calcium imaging of MOR function in cultured neonatal and adult rat dorsal root ganglion cells. Calcium imaging showed that a significantly greater number of neonatal DRG neurons expressed functional MOR compared to adult (56.5+/-3.4 versus 39.9+/-1.5%, n=8, mean+/-SEM, P<0.001). This expression is confined to the large, neurofilament positive sensory neurons, while expression in small, nociceptive, neurofilament negative neurons remains unchanged. Sensory threshold testing in rat pups showed that the analgesic potency of systemic morphine to mechanical stimulation is significantly greater in the neonate and declines with postnatal age. Morphine analgesic potency in thermal nociceptive tests did not change with postnatal age. These experiments show that the MOR expressed on large DRG neurons in neonates are functional and are subject to postnatal developmental regulation. This changing functional receptor profile is consistent with greater morphine potency in mechanical, but not thermal, sensory tests in young animals. These results have important clinical implications for the use of morphine in neonates and provide a possible explanation for the differences in morphine requirements observed in the youngest patients.