for learning and revision purposes

1. INTUBATION AND
EXTUBATION
Endotracheal intubation is the most definitive way of maintaining airway in
patients who require muscle paralysis and require intermittent positive
pressure ventilation. It involves introduction of a tube into the trachea for
maintaining the patency and protecting the airway as well as to ensure
adequate oxygenation and ventilation. Whenever general anaesthesia is
induced and needs to be maintained for long periods, endotracheal
intubation is done

2. Indications
• To administer general anaesthesia for long(> 1-2 h) periods.
• To maintain patency of the airway in unconscious
• To ensure delivery of adequate tidal volumes to the lungs.
• To clear excessive and retained secretions from the lungs.
Contraindications
Endotracheal intubation may be extremely difficult and even
dangerous. A tracheostomy may be better in such situations.
• When the upper airway integrity is lost as in extensive maxillofacial
injury with bilateral fractures of mandible and maxillae.
• Injuries to the neck with laryngeal rupture
• Large tumours of the upper airway.

3. Equipment Laryngoscopes
These consist of a handle and a blade. The handle contains batteries. The
blade has a flange to push the tongue towards the left side. This ensures more
room for visualisation of the glottis. A bulb nearer the tip of the blade lights up
when the handle and blade are at right angles to each other and electrical
contact is made.
• There are several types of laryngoscopes to aid in different situations.
- Macintosh type blade is curved and is popular for use in adults.
- - The Miller blade is straight and is used in children and in adults with
difficult airway.
The McCoy laryngoscope has a tiltable tip.
Bullard laryngoscope for use in patients with cervical spine immobility.
- Fibreoptic laryngoscopes are flexible.
- Video laryngoscopes have a small camera on the blade a little proximal to
the tip and provide a better view of 'difficult to see' larynx.
- Short-handled laryngoscopes are available for use in difficult airways, e.g.
pregnant women, obese

4. Endotracheal tubes
It is a 'C'-shaped tube and is commonly made of polyvinyl chloride (PVC).
The machine end has a standard 15 mm diameter connector. The patient end is bevelled and has an opening on
the side just proximal to the tip called the Murphy's eye. This ensures patency of the tube even if the bevelled tip
is against the tracheal wall.
Endotracheal tubes are available in different sizes. Their size is indicated as the internal diameter in mm However,
the correct size will depend on the growth of the child
• Adult male
• Adult female
• Children < 6 years
• Children > 6 years
Endotracheal tube size
8 or 8.5 mm/D
7 or 7.5 mm/D
Age/3 + 3.5 mm/D
Age/4 + 4.5 mm/D
.

5. Depth of insertion
• The distance of several points on the tube from the patient end is marked in cm along the tube.
The tube is fixed at 22 or 23 cm in adult men and at 20 or 21 cm in adult women.
• In children, the following formula is used: Age/2 + 12 cm.
The tube should be positioned such that its tip must lie above the carina but well below the glottis.
Position
A pillow (7-10 cm) under the patient's head enables mild flexion at the cervical spine. The head is
then extended at the atlanto-occipital joint. This is called the intubating position or "sniffing
position". Route Endotracheal intubation can be done either orally or nasally . It can be done
either under direct vision or indirectly using a fibreoptic scope. It may need to be done blindly
when visualisation of the glottis by direct means is not possible and a fibreoptic scope is not
available. In such cases, if the regular antegrade technique (mouth or nose to larynx) is not
possible, retrograde intubation (larynx to mouth) may be tried. In the retrograde technique, a guide
wire is passed from the cricothyroid membrane upward into the mouth or nose and the
endotracheal tube is guided over it.

6. Procedure
The patient's head is placed in the sniffing position. The mouth is opened and the laryngoscope
blade is introduced through the right angle of mouth along the tongue into the pharynx. Once
the epiglottis is seen, the tip of the laryngoscope blade is pressed into the vallecula. This lifts up
the epiglottis to reveal the glottis. The glottis is identified by the two pearly white vocal cords.
Once the cords are seen, the endotracheal tube is inserted between them into the trachea.
ENDOTRACHEAL INTUBATION
• Orotracheal or nasotracheal
• Direct or indirect (using fibreoptic laryngoscope)
• Under vision or blind
• Anaesthetised or awake
• Antegrade or retrograde
Many airway adjuncts are available for use when a difficult airway is encountered, especially
when it is unanticipated.
These include oropharyngeal airway, nasopharyngeal airway, laryngeal mask airway .

7. Confirmation of correct placement of endotracheal tube
Correct position of the endotracheal tube may be confirmed by the following
• Endotracheal intubation under vision
• Bilateral visible chest rise
• Bilateral equal air entry in the lungs
• Absent breath sounds in the epigastrium
• A square wave normal capnogram-gold standard.
Complications
The complications of endotracheal intubation may be classified as follows
Immediate
• Trauma to teeth, lips, tongue, pharynx or larynx
• Haemodynamic changes-tachycardia, hypertension, myocardial ischaemia
• Misplaced tube-accidental extubation, oesophageal intubation
Delayed
Laryngeal granuloma, laryngeal or subglottic stenosis

8. Oropharyngeal airway
• It is available in various sizes.
The correct size is chosen such that when it is placed along the side of the patient's face, it
should extend from the angle of mouth up to the tragus.
This is inserted along the tongue and reaches up to the posterior pharyngeal wall.
• Care should be taken not to push the tongue backwards with the airway itself.
• To avoid that, the airway is inserted with its concavity towards the palate and then turned
once 50% ofit is inserted and passed further.
• Please note that an oropharyngeal airway is excellent in patients who are completely
unconscious. Patients who are conscious do not tolerate it.
In patients who are semiconscious, it may initiate a gag reflex and induce vomiting. In such
patients, a nasopharyngeal airway 1s a better choice.
Nasopharyngeal airway.
• It is a soft tube made of latex or silicon.
It is available in various sizes. The correct size is the same size as an endotracheal tube for
that patient.
• The correct length is chosen such that when it is placed along the side of the patient's face,
it should extend from

9. Endotracheal extubation
Endotracheal extubation is as important as intubation.
A patient's trachea may be extubated when the following criteria are met
• Oxygenation and ventilation are satisfactory
• Patient is haemodynamically stable.
• Patient is fully conscious
• Able to maintain his airway patency
• Airway reflexes are intact
• Able to cough and clear airway.
Equipment for reintubation and personnel skilled inintubation should be readily available. After a
good oropharyngeal suction to clear the secretions, the cuff is deflated and the tube removed.
Oxygen should be administered by face mask and the patient monitored till he is stable and ready
to go to the ward.