Ventilation Under Anesthesia

Question 1

Predictors of difficult mask ventilation?

Answer 1

1. Obesity/large tongue
2. Facial hair/beard
3. Edentulous/Prominent overbite
4. Neck/facial trauma
5. Foreign body/pharyngeal abscess or mass
6. Airway swelling

Question 2

Causes of ineffective mask ventilation?

Answer 2

1. Soft tissue airway obstruction
2. Not enough pressure in circuit (usually leak around mask)
3. Too much pressure in circuit (APL close too much)

4.

Question 3

If airway obstruction is present, the anesthetist can relieve the obstruction by:

Answer 3

1. Using a nasal or oral airway
2. Doing a jaw thrust and using a double handed masking technique

Question 4

Protocol for difficult mask ventilation?

Answer 4

1. Properly align airway axis’
2. Place oral or nasal airway
3. Double handed mask technique with oral airway in place
4. LMA
5. Wake patient up, or try to intubate the patient

Question 5

Disadvantages of mask ventilation?

Answer 5

1. Hands are “not free”
2. May be difficult to ventilate some patients with <20cmH20 pressure (obese, tendelenburg position, etc.)
3. Airway is not protected

Question 6

Benefits of LMA?

Answer 6

1. Relieves all airway obstruction
2. Creates a seal in the pharynx
3. Accomplishes everything masking does, but now the anesthetists hands are “free”!

Question 7

Limitations of LMA?

Answer 7

1. Limited to using <20cmH20 pressure
2. LMA doesn’t protect the airway
3. Ventilator should not be used, unless it is in pressure control and set to <20cmH20

Question 8

Types of ventilation under anesthesia

Answer 8

1. Spontaneous ventilation (Patient breathes on thier own, and must be in “bag” mode)
2. Assist ventilation (Squeezing bad occasionally just as patient starts to inhale)
3. Control ventilation (mechanical ventilation)

Question 9

Absolute contraindications for LMA

Answer 9

1. Full stomach (Delayed gastric emptying, not NPO, bowel obstruction)
2. Narcotic use, trauma, diabetic patients, neonates
3. Laboring pregnant patients
4. Liver failure with ascites
5. Obesity
6. Decreased tone of the lower sphincter
7. Hiatal hernia
8. Surgery requiring paralysis (abdominal, laparoscopic, hip replacement, cardiothoracic, etc.)
9. Patients having to be on ventilator
10. Long procedures, when you need greater than >20cmH20