D. G. Mason

Obstructive sleep apnoea syndrome in children

Obstructive sleep apnoea syndrome in children is a complex disorder characterised by repeated nocturnal episodes of increased upper airway resistive load. It is most commonly associated with adenotonsillar hypertrophy and more children are now presenting for adenotonsillectomy. These children may pose different anaesthetic problems to those having surgery for recurrent infection alone and anaesthetic morbidity and mortality has been reported. In addition, due to the varied symptomatology of the condition, children with unrecognised obstructive sleep apnoea syndrome may present for incidental surgery. This is of importance as patients with undiagnosed obstructive sleep apnoea syndrome may experience additional peri‐operative morbidity when undergoing incidental surgery. This article aims to review the aetiology, pathophysiology, clinical presentation and anaesthetic management of children with obstructive sleep apnoea syndrome.

A survey of pediatric caudal extradural anesthesia practice

Background:  Caudal extradural blockade is one of the most commonly performed procedures in pediatric anesthesia. However, there is little information available on variations in clinical practice.

A comparison of the laryngeal mask airway with facemask and oropharyngeal airway for manual ventilation by critical care nurses in children.

The laryngeal mask airway is included as a first line airway device during adult resuscitation by first responders. However, there is little evidence for its role in paediatric resuscitation. Using anaesthetised children as a model for paediatric cardiopulmonary arrest, we compared the ability of critical care nurses to manually ventilate the anaesthetised child via the laryngeal mask airway compared with the facemask and oropharyngeal airway. The airway devices were inserted in random order and chest expansion was measured using an ultrasound distance transducer. The critical care nurses were able to place the laryngeal mask airway and achieve successful ventilation in 82% of children compared to 70% using the facemask and oropharyngeal airway, although the difference was not statistically significant (p = 0.136). The median time to first successful breath using the laryngeal mask airway was 39 s compared to 25 s using the facemask (p < 0.001). In this group of nurses, we did not show a difference in ventilation via a laryngeal mask airway or facemask, although facemask ventilation was achieved more quickly.

A randomised, controlled trial comparing the Airtraq™ optical laryngoscope with conventional laryngoscopy in infants and children*

The Airtraq™ optical laryngoscope became available in paediatric sizes in the UK in May 2008. We conducted a randomised, controlled trial comparing the Airtraq with conventional laryngoscopy during routine anaesthesia in children. We hypothesised that the Airtraq laryngoscope would perform as well as conventional laryngoscopy. Sixty patients (20 infants and 40 children) were recruited. The mean (SD) intubation time using the Airtraq was longer than conventional laryngoscopy overall (47.3 (32.6) vs 26.3 (11.5) s; p = 0.002), though the difference was only significant for children (p = 0.003) and not for infants (p = 0.29). The Airtraq provided a better view of the larynx compared with conventional laryngoscopy (in infants (percentage of glottic opening scores 100 (95–100 [90–100]) vs 77 (50–90 [40–100]), respectively; p = 0.001; visual analogue scores for field of view 9.2 (9.2–9.5 [8.2–10.0]) vs 6.8 (5.1–8.0 [4.7–10.0]), respectively; p = 0.001). In children, the Airtraq provided a similar view of the larynx (percentage of glottic opening scores 100 (100–100 [40–100]) vs 100 (90–100 [50–100]), respectively; visual analogue scores for field of view 9.2 (8.6–10.0 [7.0–10.0]) vs 9.2 (8.6–10.0 [5.6–10.0]), respectively; both p > 0.05), compared with conventional laryngoscopy.

A comparison of the laryngeal mask airway with the facemask and oropharyngeal airway for manual ventilation by first responders in children

In adults, first responders to a cardiopulmonary arrest provide better ventilation using a laryngeal mask airway than a facemask. It is unclear if the same is true in children. We investigated this by comparing the ability of 36 paediatric ward nurses to ventilate the lungs of 99 anaesthetised children (a model for cardiopulmonary arrest) using a laryngeal mask airway and using a facemask with an oropharyngeal airway. Anteroposterior chest wall displacement was measured using an ultrasonic detector. Nurses achieved successful ventilation in 74 (75%) of cases with the laryngeal mask airway and 76 (77%) with facemask and oropharyngeal airway (p = 0.89). Median (IQR [range]) time to first breath was longer for the laryngeal mask airway (48 (39–65 [8–149])) s than the facemask/airway (35 (25–53 [14–120]) s; p < 0.0001). In 10 cases (10%) the lungs were ventilated using the laryngeal mask airway but not using the facemask/oropharyngeal airway. We conclude that ventilation is achieved rapidly using a facemask and oropharyngeal airway, and that the laryngeal mask airway may represent a useful second line option for first responders.

Paediatric caudal extradural catheterisation: an evaluation of a purpose designed equipment set.

Using a purpose designed set of equipment, the Caudal Extradural Catheter Tray, Oxford Set (B Braun Medical Ltd, Sheffield, UK) we have evaluated the ease of cannulation of the caudal space, and the subsequent success in threading extradural catheters and obtaining satisfactory analgesia via the caudal route. The set was evaluated in 91 children (age range: 1 day to 10 years). Cannulation of the caudal space was achieved in all patients, and catheterisation of the extradural space was successful in 96.7% of patients. Postoperative analgesia was satisfactory in 95% of children who had continuous extradural analgesia. There were no major complications or neurological sequelae associated with using the set. We found the Caudal Extradural Catheter Tray provides the necessary equipment to perform extradural anaesthesia and analgesia safely and successfully in children of a wide age range.

NCEPOD - so what?

Journal of Human Genetics 2003; 11: 342–8. 9 Robinson RL, Hopkins PM, Carsana A, et al. Several interacting genes influence the malignant hyperthermia phenotype. Human Genetics 2003; 112: 217–8. 10 Carpenter D, Robinson RL, Quinnell RJ, et al. Genetic variation in RYR1 and malignant hyperthermia phenotypes. British Journal of Anaesthesia 2009; 103: 538–48. 11 Punj J, Bhatnagar S, Saxena A Malignant hyperthermia in the Indian subcontinent: non-availability of dantrolene – a cause for concern? Internet Journal of Pharmacology 2001; 5: 32. http://www.ispub.com/journal/ the_internet_journal_of_ anesthesiology/volume_5_number2_ 32/article/malignant_hyperthermia_ in_the_indian_subcontinent_non_ availability_of_dantrolene_a_cause_ for_concern.html (accessed 04 ⁄ 09 ⁄ 2010). 12 Ellis FR, Halsall PJ, Christian AS. Clinical presentation of suspected malignant hyperthermia during anaesthesia in 402 probands. Anaesthesia 1990; 45: 838–41. 13 Larach MG, Localio AR, Allen GC, et al. A clinical grading scale to predict malignant hyperthermia susceptibility. Anesthesiology 1994; 80: 771–9. 14 Saxena KN, Dua CK. Malignant hyperthermia – a case report. Indian Journal of Anaesthesia 2007; 51: 534–5. 15 Jain G, Gupta SK, Tharwani S, Singh DK. Rare case of hyperthermia in aluminum phosphide poisoning. Indian Journal of Forensic Medicine and Toxicology 2010; 4: 26–7. 16 Watkins WS, Rogers AR, Ostler CT, et al. Genetic variation among world populations: inferences from 100 Alu insertion polymorphisms. Genome Research 2003; 13: 1607–18. 17 Reich D, Thangaraj K, Patterson N, Price AL, Singh L. Reconstructing Indian population history. Nature 2009; 461: 489–94. 18 Carpenter D, Morris A, Robinson RL, et al. Analysis of RYR1 haplotype profile in patients with malignant hyperthermia. Annals of Human Genetics 2009; 73: 10–8. 19 Carpenter D, Ismail A, Robinson RL, et al. A RYR1 mutation associated with recessive congenital myopathy and dominant malignant hyperthermia in Asian families. Muscle and Nerve 2009; 40: 633–9.

The Newton valve revisited: an in-vitro study of ventilator circuit dead space.

A laboratory study was conducted to investigate the volume (length) of the ventilator circuit dead space (VCD) tubing at which dilution of an inspired gas by ventilator driving gas first occurs using three lung models. Various lengths of two VCD tubing materials [Portex (Sims Portex Ltd, Kent, UK) 10 mm bore smooth‐walled silicon and Intersurgical (Wokingham, Berks, UK) 22 mm corrugated plastic] were interposed between a T‐piece circuit and Nuffield 200 ventilator (Penlon, Abingdon, Oxon, UK) with a Newton valve attached. Dilution of inspired gas by the ventilator driving gas was first detected during ventilation of infant and child lung models when the VCD was 7 ml (6 cm) and 77 ml (102 cm), respectively, using Portex tubing, and 24 ml (6.5 cm) and 105 ml (29 cm), respectively, using Intersurgical tubing. No dilution occurred using the neonatal model. Dilution of the inspired anaesthetic gases by ventilator driving gas may occur in paediatric practice if the VCD volume (length) is inadequate. This risk is greatest in the child.