Intubation in anaesthesia Flashcards
revise basic airway anatomy
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endotracheal intubation (ETT)
flexible plastic tube with an inflatable cuff (balloon) at one end and a connector at the other.
The tip of the endotracheal tube is inserted through the mouth, throat (pharynx), larynx and vocal cords into the trachea.
Endotracheal tubes come in different sizes, with the diameter written in mm (e.g., 7-7.5mm for women, 8-8.5mm for men).
inflation of the ETT cuff
Once in the correct position, a syringe can be used to inflate the cuff via the pilot line. There is a pilot balloon towards the end of the pilot line, which inflates along with the cuff and allows the anaesthetist to roughly assess how inflated the cuff is (while it is out of sight in the trachea). The pressure in the cuff can be checked with a manometer (pressure sensor) to avoid over or under-inflation. There is a valve on the end of the pilot line that keeps the pilot balloon inflated.
The Murphy’s eye provides an extra hole on the side of the tip that gas can flow through in the event that the main opening at the tip of the ETT becomes occluded (blocked).
ETT using a laryngoscope
A laryngoscope is a metal blade attached to a handle, with a light attached. It is inserted through the mouth and into the pharynx to visualise the vocal cords. An endotracheal tube can be guided along the blade into position in the trachea. A McGrath laryngoscope is a high-tech version of a standard laryngoscope, which has a camera and screen attached so that the vocal cords can be visualised via a live video feed.
ETT using a bougie
device to help with intubation, notably when the vocal cords cannot be visualised. The bougie is inserted into the trachea. The endotracheal tube slides along the bougie into the correct position in the airway. The bougie is then removed, and the endotracheal tube remains in place.
ETT using a stylet
another device to help with intubation. It is a stiff metal wire (with a plastic coating) that is inserted into the endotracheal tube before intubation is attempted. It can be bent to hold the endotracheal tube in a specific shape. It is usually used to bend the tip of the endotracheal tube anteriorly towards the trachea (to avoid going posteriorly into the oesophagus)
awake fibre optic intubation
Awake fibre-optic intubation is a special procedure where the endotracheal tube is inserted with the patient awake, under the guidance of an endoscope (camera). A long thin tube with a camera on the end (endoscope) is inserted through the nose or mouth, down to a position below the vocal cords. The endotracheal tube is then inserted over the top of this tube into the correct position. Then the endoscope is removed, leaving the endotracheal tube in position. This is used where there is restricted mouth opening or difficult anatomy (e.g., after radiotherapy to the neck). Putting the patient to sleep prior to inserting the endotracheal tube is more risky, as a delay in intubation can lead to hypoxia.
trismus
pain and restriction when opening the jaw (can make intubation difficult)
supraglottic airway devices (SAD)
alternative to ETT for intubation and ventilation
commonly used in elective and emergency scenarios
first option in difficult airway situation
SAD insertsiions
the tip of a SAD will be located at the top of the oesophagus. cuff will fit around the opening of the larynx forming a seal between the device and airway. cuff can be inflatable or. non inflatable.
SAD with inflatable cuff is a laryngeal mask airway (LMA)
a non inflatable SAD is an I-gel which uses a gel like cuff that moulds to the larynx
oropharyngeal (guedel) airway
inserted into the oropharynx. rigid and creates an air passage between in front of the teeth and the base of the tongue, maintaining a patent upper airway. They are inserted upside down, then rotated into position once the tip is past the tongue. These are most often used when ventilating the patient via a face mask and bag prior to inserting an SAD or ETT.
The size is measured from the centre of the mouth to the angle of the jaw.
nasopharyngeal airway
slightly flexible tubes inserted through the nose. They create an air passage from outside the nostril to the pharynx (throat). The size is measured from the edge of the nostril to the tragus of the ear. They are often used in emergency scenarios, for example, in A&E or at cardiac arrests. They carry a risk of nosebleeds (epistaxis). A base of skull fracture is a contraindication for inserting a nasopharyngeal airway.
tracheostomy
ostomy- new opening in the treachea
a hole is made in the front of the neck with direct access to the trachea. A tracheostomy tube is inserted through the hole into the trachea and held in place with stitches or soft tie around the neck (trach tie). Tracheostomies may be temporary or permanent, depending on the indication.
tracheostomy insertion
can be planned and inserted under a general anaesthetic or performed in an emergency with general or local anaesthetic depending on the circumstances. They are often inserted at the end of head and neck operations, for example, after a laryngectomy procedure (where a permanent tracheostomy will be required).
indications for a trachestomy
Respiratory failure where long-term ventilation may be required (e.g., after an acquired brain injury)
Prolonged weaning from mechanical ventilation (e.g., ICU patients that are weak after critical illness)
Upper airway obstruction (e.g., by a tumour or head and neck surgery)
Management of respiratory secretions (e.g., in patients with paralysis)
Reducing the risk of aspiration (e.g., in patients with an unsafe swallow or absent cough reflex)
