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Airway management. Med 5: Anaesthesia Module. Summary of skills. Resusc. Bag: Airway obstruction: Bag & Mask ventilation: Laryngoscope: Intubation of trachea: Induction sequence: Verify position of tracheal tube:. Resuscitation Bag. Oxygen supply connected here 10 L/min.
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Airway management Med 5: Anaesthesia Module
Summary of skills • Resusc. Bag: • Airway obstruction: • Bag & Mask ventilation: • Laryngoscope: • Intubation of trachea: • Induction sequence: • Verify position of tracheal tube:
Resuscitation Bag Oxygen supply connected here 10 L/min • Bag - self-inflating • Valve – unidirectional • Oxygen supply / reservoir • Face mask
Kept in theatre on wall • To transfer patients • Backup, if machine fails
Old style “size 4” face masks Note the air filled rubber seal which is contoured to fit the patient’s face They are black because the rubber contains carbon. The carbon prevents static electricity (antistatic) and sparks. An relic of days of inflammable anaesthetic gases, such as ether.
Mask held to show contours of face Recess angle of mouth Cheek Nose
Finger positions when holding a face mask Fingers: Thumb & Index hold mask Middle & Ring under the jaw Little finger at angle of jaw Together they lift the jaw
Airway Obstruction • Patient cannot breath. Air cannot be moved in and out of the lungs, despite respiratory efforts. • The patient may be very distressed. • Eventually the patient will become hypoxic, cyanosed and eventually arrest.
Conscious: Natural tone of muscles of pharynx [airway patent] Sleep: Loss of coordination Snore / sleep apnea Stroke or MN disease Bulbar palsy Unconscious: Tone is lost & tissues collapse [airway obstructs] Overdose Head injury GCS < 8/15 Airway Obstruction & Level of Consciousness
Airway Obstruction • Functional: Patient is unconscious • Tongue & epiglottis falling backwards • When patient lies supine • Tongue impinging on roof of mouth • Mechanical: Blockage of the lumen • Foreign bodies (vomit / blood) • Swelling of soft tissues (infection) • Enlarged tongue of tonsils
Airway Obstruction • How is functional obstruction treated? • Patient position (Supine to lateral) • Recovery position (tongue falls forward) • Jaw (lift) / neck (extension) maneuver • Lifts up the tongue & epiglottis • Airway devices that provide a patency : • Oral airway • Laryngeal mask airway • Endotracheal tube (ETT)
Obstructed Airway a. Patient lies supine b. Head in neutral position c. Tongue & epiglottis fall backward onto the posterior pharyngeal wall
Unobstructed Airway a. Jaw lift / Head tilt b. Tongue & Epiglottis now clear of posterior pharyngeal wall a a b
A Resuscitation Annie is used to practice bag & mask skills, including jaw lift & head tilt and ventilation
Neutral position Airway Obstructed Unable to ventilate Note position of hand on mask Two (2) fingers hold mask Three (3) fingers hold jaw Mask in tight contact with face
Jaw (lift) & Neck (extended) Airway now patent Tongue & epiglottis lifted up Able to ventilate lungs No resistance when squeezing resusc. bag
Ventilation • Rate: 12-15 per minute • Volume: reasonable chest movement • (~500 ml: Resusc. Bag 2 litres) • It is important to observe (& auscultate) the chest (& abdomen) to confirm that you are ventilating the lungs and the tidal volume is acceptable.
Providing a patent airway • 1. Positioning of patient: • Recovery (lateral) position • 2. Airway maneuvers: • Jaw (lift) & Head (tilt) {neck extended} • 3. Adjuncts to the airway: • Oral airways • LMA (laryngeal mask airway) • ETT (endotracheal tube) • 4. By-pass the larynx: • Tracheostomy
Oral airways can be used to overcome obstruction due to the tongue lying against the roof of the mouth 4 3 2 Oral airways come in different sizes
Cut away model shows how an oral airway provides a patent pathway to pharynx. The correct size needs to be selected. Note the pharynx lies in same vertical plane as the ear and auditory canal. Thus the ideal length of an oral airway is from the corner of the mouth to ear hole.
1. The correct sized oral airway is selected Note that the airway is orientated in the position it will take up when inserted into the mouth
3: The head is tilted to open the jaw and the airway is inserted towards the hard palate to avoid the tongue Note that for insertion the airway has been rotated 180o
4: The airway is rotated back to its correct orientation as advanced into the mouth
The LMA (laryngeal mask airway) 1 2 3 • Inflatable cuff (25-30 ml air) • Stalk with universal (15 mm) connector • Pilot balloon (with syringe) • Plastic / reused < 40 times
LMA with cuff inflated The LMA is a relatively new innovation in anaesthesia, introduced in the late 1980s
Placement of an LMA in an anaesthetized patient The LMA is inserted into the mouth of the unconscious patient and advanced into the pharynx until it will go no further. Then the cuff is inflated with 25-30 ml of air. It is then checked for patency and the ability to ventilate both lungs.
Cut away model showing how the LMA is positioned over the laryngeal opening in pharynx when its cuff is inflated
Design of ETT (endotracheal tube) Plastic: Clear, disposable & non-allergy Cuff with Pilot balloon (5-10 ml air) Seal to keep air (in) / vomit (out) Connector (a): Universal size 15 mm Markings: Size, length & position a
Cut away model showing position of ETT in airway Mark on ETT to help position it at level of vocal cords
Close up view of the inflated cuff & pilot balloon and the markings (a) that denote the placement level with respect to the vocal cords a
Some more unusual airway tubes Armoured non-kinking tube Old style red rubber double lumen tube used for lung surgery Armoured preformed tracheostomy tube for intra-operative use Latex nasal airway
Machintosh Laryngoscope: Upper scope is ready for use with light switched on. Lower scope is in off position. The light is housed in the handle with an optical conduit in the blade.
Disassembled Laryngoscope a Identify: Handle, blade, light source (a) & batteries with housing Note that the blade has a optical conduit to transfer light source Older style scopes had a screw in light bulb on the blade
Laryngoscope held in LEFT hand, Person intubating stands at head end of patient Note (a) how the handle is grasped and (b) The orientation of blade in the mouth Note: Too much pressure on upper teeth
View of larynx from above: Be able to identify: Base of tongue Epiglottis Vocal cords Trachea Arytenoids Oesophagus
Identify structures Note nodule on closed vocal cords
Laryngoscope blade is positioned at the valecula (base of tongue) superior to the epiglottis Note that the blade is inserted carefully into the mouth and walked down the tongue to be positioned at its base.
Outline of upper airway TONGUE Posterior tongue & epiglottis obstruct view of larynx. During laryngoscopy they are displaced forward by scope blade
A: The pathway from the mouth to larynx is a right angle in the neutral position
B: But when the neck is extended The pathway becomes a straight line The tongue & epiglottis remain a problem and have to be displaced by using a laryngoscope
A: Neutral position: Laryngoscope blade only reveals posterior wall of pharynx