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NIHR Signal Infants anaesthetised without placing a tube in the trachea have fewer adverse breathing events

Published on 11 July 2017

doi: 10.3310/signal-000443

Adverse breathing events are about three times more common when using endotracheal tubes than laryngeal mask airways for infants under 12 months receiving non-urgent surgery.

Airway problems are common during anaesthesia in children, accounting for three quarters of critical incidents and a third of cardiac arrests. They are more frequent in younger children, especially infants under 12 months, who have smaller airways and rapidly use up their oxygen reserves.

Laryngeal mask airways have been used in adults and older children for over 35 years for minor and intermediate surgery. Many studies have shown them to have fewer airway-related complications than tubes. This Australian randomised controlled trial supported this, finding an adverse event rate of 53% with endotracheal tubes compared with only 18% with laryngeal mask airways.

Conventional anaesthesia teaching advises the use of endotracheal tubes in infants even for relatively minor surgery, to provide a secure airway, but incidents may be more common when placing or removing the tube than a laryngeal mask.

  •   Child Health, Perioperative care, Respiratory disorders

Why was this study needed?

Over 8,000 infants have surgery in the UK each year. Most will be cared for in one of the 29 paediatric surgical units in the UK, with specialist paediatric anaesthetic care.

Keeping a clear passage to the lungs is a fundamental part of safe anaesthesia. This is commonly assured using specialised tubes which pass between the vocal cords into the trachea or with laryngeal mask airways (LMAs) which sit in the throat just above the vocal cords. LMAs have been in widespread use in adults and older children for over 30 years but not in infants where their position may be more precarious. In older children, randomised trials have shown that LMAs are at least as safe as tracheal tubes while observational studies in infants have shown they caused fewer airway problems. This study is the largest trial of airway devices in infants.

What did this study do?

This was a single-centre randomised study based in Perth, Australia. Children aged under 12 months having non-urgent surgery (but not involving airway, chest or abdomen) were allocated to endotracheal tube (ETT) or LMA airway management. Complete data sets were obtained for 177/181 infants.

Respiratory adverse events included spasm of the vocal cords or lower airways, reduced blood oxygen level, persistent coughing or high-pitched breathing noises. Events in hospital were recorded by the attending anaesthetist, who was independent of the study team, and parents contacted by telephone on the postoperative day.

Other aspects of anaesthetic technique were determined on an individual basis and not standardized, reflecting usual care in Australia. This is similar to that in the UK, so results should be applicable here.

What did it find?

  • Respiratory adverse events were recorded in 65 of the 177 infants in this study.
  • Respiratory adverse events were significantly more common with ETT than with LMA: 53% (50/94) vs 18% (15/83) (relative risk [RR] 2.94 95% confidence interval [CI] 1.79 to 4.83).
  • After discharge from hospital, parents of 7/83 (9%) children who received LMA reported breathing problems, compared with 18/94 (22%) after ETT (RR 2.55, 95% CI 1.14 to 5.76). There were no significant differences in reports of other adverse effects such as pain, irritability, nausea, vomiting or feeding problems.
  • Serious adverse events of spasm of the vocal cords or lower airways occurred in 18/94 (19%) in the ETT group compared with only 3/83 (4%) in the LMA group (RR 5.30, 95% CI 1.62 to 17.35).
  • At study start researchers calculated that 290 participants would be needed to detect reliable difference between groups. Planned analysis after the first 50% (145 infants) were recruited showed a clear advantage of LMA, and therefore the study was terminated early.

What does current guidance say on this issue?

There is no formal guidance from the National Institute for Health and Care Excellence, or from the Association of Paediatric Anaesthetists (UK) on the choice of airway device for anaesthesia in infants.

What are the implications?

For minor elective surgery in infants, such as hernia repair or orthopaedic surgery, LMAs are associated with important reductions in adverse respiratory events compared to ETTs.

Tracheal tubes provide a secure airway and protect the lungs from aspiration; LMA’s are easier to insert and cause less stimulation to the vocal cords but suboptimal position may be more common. These factors should be considered when planning airway management for each individual child.

Although laryngeal mask airways are being used more often in infants undergoing minor and intermediate surgery, tracheal tubes remain the standard in airway management for most major procedures.

Citation and Funding

Drake-Brockman TF, Ramgolam A, Zhang G, et al. The effect of endotracheal tubes versus laryngeal mask airways on perioperative respiratory adverse events in infants: a randomised controlled trial. Lancet. 2017;389(10070):701-8.

The study was funded by the Princess Margaret Hospital Foundation, National Health and Australian Medical Research Council, Stan Perron Charitable Trust, and Callahan Estate.

Bibliography

Luce V, Harkouk H, Brasher C et al. Supraglottic airway devices vs tracheal intubation in children: A quantitative meta-analysis of respiratory complications. Paediatr Anaesth. 2014;24(10):1088-98.

Holm-Knudsen RJ, Rasmussen LS. Paediatric airway management: basic aspects. Acta Anaesthesiol Scand. 2009;53(1):1-9.

Expert commentary

The findings of this study provide robust evidence to support the use of a laryngeal mask airway during anaesthesia for minor elective surgery in infants. The use of a laryngeal mask airway during minor surgery is common place in adults and older children, and the findings of this trial suggest the same may well be true in infants. Perioperative respiratory complications carry significant risk of morbidity and mortality and this study will help clinicians to implement a change of practice that will make surgery safer for infants. Anaesthetists that provide care for infants should consider this study carefully when reflecting upon their current practice.

Dr Daniel Martin, Senior Clinical Lecturer in Anaesthesia & Critical Care Medicine, University College London