Healthcare and Medicine Reference
In-Depth Information
CHAPTER 14
Therapeutic: Airway - Insertion of
Laryngeal Mask Airway
Tim Nutbeam
West Midlands School of Emergency Medicine, Birmingham, UK
Anatomy
OVERVIEW
The anatomy of the pharynx and larynx has been covered in
Chapter 15. The LMA when inserted correctly sits at the
interface between the trachea and the oesophagus. Here it forms
a low-pressure seal around the glottis (see Figure 14.1).
By the end of this chapter you should be able to:
understand the indications for inserting a laryngeal mask
airway (LMA ® )
be aware of the various types of LMA
describe how to size and insert a LMA
Equipment
understand the benefi ts and limitations of the LMA.
The LMA exists in a multitude of forms. The basic LMA consists of
the following (Figure 14.2).
15-mm connector
Introduction
The laryngeal mask airway has an important role in advanced
airway management. It is recommended for use in patients requir-
ing advanced life support and is relatively easily inserted by the
non-specialist.
. This is a standard connector which will attach
to a bag-valve-mask, ventilator, fi lter etc.
Tu b e
. An anatomically designed semi-fl exible tube. A black line
often runs along the back of the airway enabling easy orientation
(should face towards the practitioner at the 'head' end).
Infl ation port
. The volume of air to be injected through this one-
way valve can be found in Table 14.1. It is important to note that
LMAs are removed fully infl ated (unlike an ET tube where the
cuff is fully defl ated before removal).
Aperture bars
Indications
A fi rst-line airway management device in those with limited
airway management experience.
Airway management in an unconscious patient who requires
. These prevent the airway becoming obstructed by
the patient's epiglottis (not universal).
Cuff
assisted ventilation in the absence of the ability to provide a
defi nitive airway.
As an alternative to oropharyngeal and nasopharyngeal airways
• . An infl atable cuff, anatomically designed to form a low-
pressure seal with minimal mucosal pressure.
Variations upon the 'classic' LMA exist which have been designed
with additional features:
(more suitable for prolonged ventilation).
Emergency airway management at a cardiorespiratory arrest.
Suitable airway device for certain operations/anaesthetics.
Part of a 'failed intubation' drill (alternative to ET tube).
Contraindications
When a defi nitive airway (cuffed tube in the trachea)
is required.
High-risk anaesthetics.
Patient with fl uctuating consciousness level (intact gag refl ex is a
contraindication due to risk of inducing vomiting).
Unconscious patients unable to open mouth (e.g. trismus).
Patients requiring high airway pressure to ventilate (e.g. heavily
pregnant, obese, asthmatic).
Figure 14.1 The position of the LMA when correctly inserted.
 
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