Airway management and ventilation

Question 1

Endotracheal ventilation

• where is the tube placed
• uses

Answer 1

Endotracheal ventilation

Tube is placed into trachea via mouth (orotracheal) or via nose (nasotracheal)

Aim: to maintain patent airway

Use:

• perioperative management of anaesthetised patient
• emergency medicine: acute respiratory failure, poor oxygenation and ventilation, the risk of respiratory compromise

Question 2

What else should be used (as a guide) in endotracheal intubation?

Answer 2

Laryngoscope - to visualise pharynx

Question 3

What is indicative of the correct placement of the endotracheal tube? (2)

Answer 3

• bi-lateral breath sounds on auscultation
• exhaled CO2 measurement

Question 4

Possible complications of endotracheal tube insertion (4)

Answer 4

• dental damage
• tracheal stenosis
• oesophageal misplacement of the tube
• infections

Question 5

What is the preferred mode for long-term intubation?

Answer 5

Tracheostomy

Question 6

What does tracheostomy involve?

Answer 6

Creation of reversible or permanent stoma below a cricoid cartilage

Question 7

When do we use the procedure of cricothyrotomy?

Answer 7

Cricothyrotomy is usually used as a last resort - in emergency situations such as acute obstruction of the airway by blood, oedema or foreign body

*also used if intubation/ventilation with the supraglottic device has failed

Question 8

Where the incision is made in cricothyrotomy?

Answer 8

In cricothyroid membrane

Question 9

What is done once the access to the airway (intubation) has been gained? What’s the next step? Why?

Answer 9

Mechanical ventilation

Aim: to assist and replace spontaneous breathing

Question 10

What are the complications of mechanical ventilation?

Answer 10

• barotrauma (e.g. pneumothorax)
• ventilator-induced lung injury -> clinically looks like Adult Respiratory Distress Syndrome

Question 11

What GCS would be indicative for endotracheal ventilation?

Answer 11

GCS of =/< 8

*as in that case protective reflexes such as cough and gag will be reduced -> so can insert endotracheal tube

Question 12

What do we need to do before extubation and why?

Answer 12

• We need to suction airways
• Aim: to minimise the risk of aspiration (fluids, foreign materials)

Question 13

Criteria for extubation (what would be indicative to extubate a patient?) - 3 criteria

Answer 13

• sufficient spontaneous breathing
• presence of protective reflexes (coughing, swallowing)
• adequate level of consciousness (eye-opening, obeying requests)

Question 14

Where the incision is made in tracheostomy?

Answer 14

Tracheostomy

Horizontal incision between cricoid cartilage and sternal notch -> insertion of suture and fixation of tracheostomy tube

Question 15

What must be done and why post- tracheostomy insertion?

Answer 15

Post tracheostomy

Chest X-ray -> to exclude pneumothorax and tube displacement

Question 16

Definition of mechanical ventilation

Answer 16

Mechanical ventilation - use of respirator to assist or completely replace spontaneous breathing

Question 17

What agents do we use to suspend spontaneous breathing (for purpose)? (3)

Aims

Answer 17

• opioids
• muscle relaxants
• hypnotic agents

Aim: to permit intubation, suppress respiratory centres, reduce muscular resistance for mechanical ventilation

Question 18

What is capnometry/capnography?

Answer 18

Allows assessment of CO2 concentration in exhaled air -> to determine if ventilation is adequate

Question 19

What’s weaning?

Answer 19

The process of easing a patient off mechanical ventilatory support

Question 20

Side effects of mechanical ventilation?

Answer 20

If PEEP (positive end-expiratory pressure) is set too high: inflation of the lung with decreased compliance

• Barotrauma → rupture of alveoli → pulmonary emphysema, pneumomediastinum, pneumoperitoneum, pneumothorax, and/or tension pneumothorax.
• ↓ Cardiac output (as venous return is obstructed by increase in intra-thoracic pressure)
• ↓ Liver perfusion

Question 21

Mechanism of action of a ventilator

Answer 21

Mechanism of action

• PEEP (positive end-expiratory pressure)↑ alveolar pressure and alveolar volume → collapsed or unstable alveoli reopen → improves ventilation/perfusion relation
• Provides an adequate arterial PaO2 at a low and safe concentration of oxygen (< 60%) → reduces the risk of oxygen toxicity

Question 22

Bronchospasm

• what is this/what happens?
• what does it lead to?

Answer 22

Bronchospasm

Bronchoconstriction during anaesthesia -> leads to severe hypoxia and hypotension if left untreated

Question 23

Risk factors for bronchospasm (3)

Answer 23

• smoking
• reactive airway disease (asthma, COPD)
• viral upper respiratory tract infection

Question 24

Clinical features of bronchospasm

Answer 24

Clinical features of bronchospasm

• Acute onset of dyspnea
• Wheezing
• Prolonged expiration
• ↑ Peak airway pressures and ↓ tidal volumes

Question 25

Treatment of bronchospasm

• basic management
• pharmacological (1st and 2nd line)

Answer 25

A. Basic measures

• Discontinuation manipulating measures/surgery
• Manual ventilation with a FiO2 of 100%
• Deepen anesthesia
• Exclude differential diagnosis (e.g. pneumothorax, laryngospasm)

B. Pharmacotherapy in severe bronchospasm

• First-line: salbutamol
• Secondline: adrenaline, ipratropium, hydrocortisone