Paediatric difficult airway management

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Originally from Update in Anaesthesia | www.wfsahq.org/resources/update-in-anaesthesia

Michelle C White* and Jonathan M Linton

*Correspondence email: mcwdoc@doctors.org.uk

Dr Michelle White, Consultant Anaesthetist, Mercy Ships, Guinea

Dr Jonathan Linton, Specialist Trainee Anaesthesia, University Hospital, Southampton, UK

Summary

Unexpected difficult airways in paediatric practice are rare. Many problems can be prevented by routine preoperative airway assessment, pre- xygenation, and preparation of equipment. A simple step-wise approach to management improves outcome. Anaesthetists have a responsibility to be familiar with airway algorithms and make pragmatic modifications to account for available resources.

INTRODUCTION

Airway management in children is generally straightforward in experienced hands. Problems are more common for the non-paediatric anaesthetist, and are a major cause of anaesthesia-related morbidity and mortality. Genuine ‘difficult airways’ are rare in children compared to adults and many are predictable. However, differences in adult and paediatric physiology mean irreversible hypoxic damage occurs more quickly in children if there is an airway problem. Simple stepwise strategies are essential. Many guidelines exist for the management of difficult airways in adults, but there are few specifically designed for use in children. The aim of this article is to outline the basic principles of paediatric airway assessment and to discuss the management of unexpected and expected difficult paediatric airways. Evidence to support best practice is difficult to obtain for unpredictable events such as management of the paediatric difficult airway, and there is a lack of high quality data. Many new devices and techniques are available, but most are evaluated in healthy children or simulated ‘difficult’ situations. Due to this lack of evidence, guidelines are often based on a consensus of expert opinion, which may have a bias against newer devices and techniques, or indeed bias towards the latest technique that has gained popularity. This review takes a pragmatic and cautious approach in applying existing guidelines to settings where experts and a range of technology are not always available.

BACKGROUND

Management of the difficult airway can be divided into three critical areas:

1. Difficult mask ventilation

2. Difficult tracheal intubation

3. Can’t intubate and can’t ventilate (CICV).

The incidence of difficult airways in children is unknown. The incidence of impossible mask ventilation is reported as 0.15%, and is more frequently encountered by inexperienced paediatric anaesthetists. Difficult intubation ranges from 0.05%, rising to 0.57% in children less than one year of age. Difficult intubation is more common in children with cleft lip and palate (4.7%) and cardiac abnormalities (1.25%), most likely related to associated syndromes or limited cardiac reserve.

An audit of difficult airway management in the UK in 2001 (the 4th National Audit Project, NAP 4), prospectively measured major airway complications in almost 115,000 patients undergoing anaesthesia. Children comprised a small proportion of the total population, and complications were rare (only 7-8% of total complications).

Common contributing factors to bad outcomes were:

• Poor airway assessment

• Poor planning

• ‘Failure to plan for failure’

• Repeated attempts at intubations

• Lack of monitoring (oxygen saturation and capnography)

• Slow response to hypoxia resulting in bradycardia leading to cardiac arrest

• Failure to use devices such as the laryngeal mask airway (LMA) when faced with a difficult intubation.

One of the key findings in NAP4 was the ‘failure to plan for failure’. Airway management plans should always include a back-up plan to use if the first plan fails. Whenever unexpected difficulties occur, seek experienced help immediately. Another key finding of NAP4 was that repeated attempts at intubation can cause severe airway oedema in children and worsen the situation, hence their recommendation, ‘a change of approach is required, not repeated use of a technique that has already failed’. Many countries have adult guidelines for management each of difficult airways, but few have child specific guidelines. The Association of Paediatric Anaesthetists of Great Britain and Ireland (APA) published paediatric guidelines in 2012, which are shown in Figures 1-3 and form the basis for management of the unexpected difficult airway discussed here.