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Airway management 

Airway management
Chapter:
Airway management
Author(s):

Stephen Chapman

, Grace Robinson

, John Stradling

, Sophie West

, and John Wrightson

DOI:
10.1093/med/9780198703860.003.0062
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date: 26 October 2021

Simple airway adjuncts

Simple airway adjuncts

are used to overcome backward tongue displacement in an unconscious patient.

Airway management Call for anaesthetic help early

Patients may require support of their airway and ventilation/oxygenation in situations when they are unable to adequately maintain these. Such situations may be related to a GCS of <8, which can cause difficulties with airway maintenance, or related to respiratory compromise or arrest in the critically ill patient.

Oropharyngeal airway (Guedel)

A curved plastic tube with a flanged end that is inserted into the mouth. Size is estimated by holding it at the side of the patient’s face and estimating required length from incisors to angle of the jaw. Ensure the mouth is clear, then insert the airway ‘upside down’, with the curved side towards the tongue. When it is in as far as the soft palate, turn it around by 180°, and push it in further so the flange is at the patient’s mouth. If the patient has a gag reflex, remove the airway. Suction can be performed through the airway and O2 administered via a mask.

Nasopharyngeal airway

A soft plastic tube, with a bevelled end and a flange at the other end. Better tolerated in the semi-conscious. Avoid use in those with base of skull fractures. Sizes 6–7mm are suitable for adults. Some tubes allow insertion of a safety pin through the flange (prior to use) to prevent insertion beyond nares. Lubricate airway with water-soluble jelly, and insert the bevelled end into right nostril, and gently push back with a twisting action along the floor of the nose. Do not force if obstruction is encountered, but remove and try in the other nostril. Nasal bleeding can be caused if the mucosa is damaged. O2 can be administered through a mask.

Intubation

Endotracheal tube

The optimal method of managing a patient’s airway and providing airway protection from aspiration of gastric contents. Requires training in tube insertion. The tube is bevelled at one end with an inflatable cuff and has a connector at the other end. The connector can be removed if the tube needs to be cut but can be replaced.

  • Predictors of difficult intubation should be considered, including Mallampati score (see Airway management p. [link]), ability to protrude mandible, assessment of neck movements, interincisor distance (<3cm predicts difficulties), thyromental distance (Patil’s test; <7cm predicts difficulties), and obesity

  • Ensure all equipment is to hand—laryngoscope (usually a size 3/4 curved Macintosh blade; check light source), cuffed endotracheal tube (variety of sizes should be to hand; usually use size 7—♀, size 8—♂; check cuff for leak), syringe for cuff inflation, water-soluble lubricating jelly, Magill’s forceps, gum elastic bougie, suitable bandage to secure tube in place, capnography and stethoscope (for confirming tube placement), O2 and suitable breathing circuit (e.g. self-inflating bag or Water’s circuit), suction (Yankauer and flexible catheters), and rescue equipment for failed intubation

  • Patient lies flat, with neck flexed and head extended (the ‘sniffing the morning air’ position). A pillow is placed under the head, not the neck, to aid this

  • Pre-oxygenate with bag-and-mask ventilation

  • Cricoid pressure (30N over the cricoid cartilage) may reduce gastric inflation and aspiration of gastric contents

  • Using the laryngoscope in left hand and standing behind the head, the mouth is opened and the laryngoscope placed over the right side of the tongue and advanced

  • It may be necessary to apply suction to clear the mouth of secretions

  • When the epiglottis is seen, the laryngoscope is advanced into the vallecula, between the root of the epiglottis and the base of the tongue. Upward pressure in the direction of the laryngoscope handle is applied to lift the jaw slightly, and the cords should come into view, taking care not to damage the teeth. Laryngoscopic views are graded (Cormack and Lehane grading): grade 1, entire laryngeal inlet visible; grade 2, arytenoids and posterior vocal cords visible; grade 3, only epiglottis visible; grade 4, epiglottis not seen

  • Slide the tube through the glottis so that the cuff is a few cm past the cords, and then withdraw the laryngoscope

  • Inflate the cuff

  • Confirm adequate tube position by auscultating for breath sounds over the chest bilaterally (also absence of noise over epigastrium) and using end-tidal CO2 detection (either waveform capnography or using colorimetric litmus-based detectors); five breaths showing CO2 confirm an adequate tube position

  • If the tube is not in position, usually because it has been passed into the oesophagus, deflate the cuff and remove the tube, then re-oxygenate with the bag and mask before trying again. Pull the tube back slightly if the breath sounds are only on the right, as this suggests the tube is in the right main bronchus

  • Secure the tube

  • Administer O2 with a self-inflating bag with O2 and reservoir bag

  • CXR to confirm correct tube position, 2–3cm above the carina

  • Suction can be performed through the tube

  • Various techniques can be used to assist with difficult tracheal intubation. A gum elastic bougie may be easier to pass through the glottis (allowing endotracheal tube insertion by railroading over the bougie). The BURP technique (external Backward, Upward, and Rightward Pressure on the thyroid cartilage) may improve laryngoscopic view. Other laryngoscope blades (e.g. McCoy levering laryngoscope) and videolaryngoscopes may be useful.

Laryngeal mask airway

A supraglottic airway device used as an alternative to formal intubation. A wide-bore tube with an inflated cuff at one end, which is positioned over the larynx and inflated, hence forming a seal; thus, aspiration of gastric contents and gastric inflation are minimized. It is easy to insert (see Fig. 62.1) and is used in anaesthetic practice and also in emergencies. Requires minimal head tilt so is ideal for use in patients with possible cervical spine injuries. Not suitable for patients with high airway resistance such as pulmonary oedema, bronchospasm, or COPD. Select a size 4 or 5 tube, and, after ensuring the cuff works, deflate it. Put water-soluble lubricating jelly over the cuff. The patient should be lying flat, with head extension, if possible. Hold the tube like a pen, and insert from behind the patient’s head, with the point of the cuff positioned to the back of the mouth. Advance along the roof of the mouth, and then press it downwards and backwards until resistance is felt. Inflate the cuff, which will cause the tube to lift out of the mouth a little. Confirm adequate airway position by auscultating for breath sounds over the chest bilaterally. Secure the tube.

Fig. 62.1 Diagram of laryngeal mask airway insertion. Reproduced from Wyatt et al. Oxford Handbook of Emergency Medicine 3e, 2006, with permission from Oxford University Press.

Fig. 62.1 Diagram of laryngeal mask airway insertion. Reproduced from Wyatt et al. Oxford Handbook of Emergency Medicine 3e, 2006, with permission from Oxford University Press.