Lecture Notes in Anaesthesia - Chapter 4

Question 1

Checking the anaesthetic machine

Answer 1

Question 2

Components of “sign in” (5)?

Answer 2

1. Confirm patient ID, operation and surgical site marked. Check consent form.
2. Record check of anaesthetic machine and drugs required for case.
3. Check any known allergies
4. Identify problems with airway management
5. Anticipated blood loss and availability of blood products

Question 3

Essential monitoring for safe conduct of anaesthesia as per AAGBI (5)

What else must be immediately available?

Additional equipment that will be needed for certain cases (3)

Answer 3

ECG, non-invasive blood pressure (NIBP), pulse oximeter, capnography, and vapour concentration analysis.

A peripheral nerve stimulator should be immediately available

Additional equipment will be required in certain cases, to monitor, for example, invasive blood pressure, urine output, CVP, and various haemodynamic parameters.

Question 4

When should temperature first be measured according to NICE?

How often should it be measured thereafter?

Answer 4

Recommendations from NICE are that all patients should have their temperature measured before induction of anaesthesia, and surgery should not be started (unless there is a critical need) if it is below 36⁰C.

Subsequently, the patient’s temperature should be measured every 30min. Active warming should be used as described below.

Question 5

What are the benefits of accessing the right internal jugular vein (3)?

Possible complications of IJ cannulation (10)?

Answer 5

There is a ‘straight line’ to the heart, the apical pleura does not rise as high on this side, and the main thoracic duct is on the left

Question 6

What is the benefit of pre-oxygenation?

How is pre-oxygenation usually achieved? What objective measure suggests it is complete?

Answer 6

Purpose of preoxygenation is to replace the ( nitrogen with oxygen, thereby significantly increasing the length of time a patient can be apnoeic (or not ventilated), without becoming hypoxic.

Breathe 100% oxygen via a close-fitting mask for about 3 minutes (until expired O2 concentration exceeds 85%).

Question 7

Induction of anaesthesia

Benefits of IV induction (2)

Disadvantages of IV induction (3)

Indications for inhalational induction (3)

Disadvantages of inhalational induction (4)

Answer 7

Benefits of IV induction

1. Rapid
2. Pharyngeal reflexes lost allowing airway insertion

Disadvantages of IV induction

1. Apnoea (require manual ventilation)
2. Hypotension
3. Loss of airway

Indications for inhalational induction

1. Lack of suitable veins
2. Uncooperative patient (child/needle phobic)
3. Airway compromise (as cannot ventilate if apnoeic)

Disadvantages of inhalational induction

1. Slow
2. Unpleasant to inhale vapours (sevoflurane most popular)
3. Hypotension without IV access
4. Hypercapnia + increased CBF - unsuitable for patients with raised ICP

Question 8

How should a NP airway be inserted? Size for women? And men?

Answer 8

Choose an appropriately sized airway, 7mm for women, 8mm for men, check the patency of the nostril to be used (usually the right) and lubricate the airway.The airway is then inserted along the floor of the nose, with the bevel facing medially to avoid catching the turbinates

Question 9

How can the position of a tracheal tube be checked (4)?

How can bronchial intubation be detected?

Answer 9

Capnography (<0.2% = oesophageal intubation)

Direct visualisation

Oesphageal detectors (a 50ml syringe is attached to the tube and the plunger rapidly withdrawn - if air is easily aspirated (likely tracheal))

Fogging on tube connectors

If tube in bronchus - unequal breath sounds

Question 10

How can hypoxia complicate intubation (4 ways)?

Which structures can be traumatised by intubation directly? And indirectly?

What reflex activities can occur secondary to intubation (3)?

Answer 10

Hypoxia

• Unrecognised oesophageal intubation - tube should be removed if doubts
• Can’t intubate, can’t ventilate
• Failed ventilation (tube issues, bronchospasm, pneumothorax)
• Aspiration - cricoid pressure reduces this

Trauma

• Directly during laryngoscopy and insertion (lips, teeth, tongue, pharynx, larynx, trachea) causing swelling and bleeding.
• Indirectly to recurrently laryngeal nerves, cervical spine and cord (particularly where there is preexisting degenerative disease)

Reflex activity

• Hypertension and arrhythmia - reduced by beta blockers or potent analgesics
• Vomiting - emergencies, delayed gastric emptying
• Larygneal spasm - reflex adduction of cords

Question 11

Which patients does NICE recommend warming?

Answer 11

A forced air-warming device should be used for all patients where anaesthesia is expected to last longer than 30 min to prevent intraoperative hypothermia.