Mechanical Ventilation Flashcards Preview

Anesthesiology > Mechanical Ventilation > Flashcards

Flashcards in Mechanical Ventilation Deck (61)
Loading flashcards...
1

How does anesthesia affect ventilation?

1. Alters CO2 sensitivity
2. Relaxes respiratory muscles
3. Develops atelectasis
4. Worsens V/Q match issues

2

How can ventilation affect anesthesia?

1. Uptake depends on ventilation
2. Controlled ventilation facilitates reliable uptake and smooth plane of anesthesia

3

What is ventilation defined by?

PaCO2

Patient should have normal resp rate, rhythm and effort

4

What is oxygenation?

Process of oxygenation of arterial blood

Defined by PaO2

5

What is oxygenation monitored by?

Arterial blood gas or pulse oximetry

6

What does oxygenation depend on?

Inspired O2%

100% O2 typically insures good oxygenation

7

What are the two phases of respiration?

Inspiration and expiration

8

What does resistance do?

Limits flow

9

What does compliance do?

Limits volume

10

Indications for mechanical ventilation?

1. Need to decrease PaCO2
2. Need to increase PaO2
3. Need to decrease respiratory effort (mostly ICU)

11

Indication for mechanical ventilation during anesthesia

1. Control of respiratory function
2. Prolonged anesthesia
3. Maintain stable anesthesia plane
4. Neuromuscular blockade
5. Thoracic surgery, chest wall, hernia
6. Obesity, increased abdomen pressure
7. head down positioning
8. Laparoscopy
9. Control ICP

12

Side effects of MV

1. Impairs venous return and cardiac output
2. May cause hypotension especially in hypovolemic patients
3. Pneumothorax and lung injury

13

Direct effects of hypercapnia

1. Peripheral vasodilation
2. Decreased myocardial contractility
3. Bradycardia and possible arrest
4. Increased ICP

14

Indirect effects of hypercapnia

1. Tachycardia, arrhythmias
2. Increased myocardial contractility
3. Increased blood pressure

15

CO2 narcosis levels

>95 mmHg progressive narcosis
>245 mmHg complete narcosis

16

What may happen if not ventilating properly?

CO2 accumulation, hypoxemia, sudden death

17

Should horses be ventilated?

Debated issue

18

Types of ventilation

Spontaneous- patient breathing
Assisted- patient timed, machine assists
Mandatory/Controlled- ventilator controls
Manual- bag
Mechanical- machine driven

19

Ventilation modes

Volume controlled
Pressure controlled

20

What can result from volume ventilation?

Pneumothorax if compliance is decreased

21

Which ventilation mode is preferred if lung volume changes during a procedure?

Pressure controlled

22

Which ventilation mode is preferred if trans-pulmonary pressure changes during a procedure?

Volume controlled

23

Which ventilation mode works well for all patient sizes?

Pressure controlled

24

Classification of ventilators

1. Source of driving power
2. Control variable
3. Cycle variable
4. Trigger variable
5. Limit variable

25

Source of driving power

1. Electronically driven
2. Pneumatically driven (pressurized gas)

26

Which source of driving power is more common?

Pneumatically driven

27

Control variables

1. Flow- delivers constant flow
2. Pressure- delivers constant patient

28

Cycle variables

Triggers expiration when a set value is reached

1. Volume
2. Pressure
3. Time
4. Flow- diminishing flow

29

What is flow variable useful for?

Pressure support ventilation- helps accommodate the patients breathing pattern

30

Trigger variable

Triggers inspiration when a set value is reached

1. Pressure- negative pressure
2. Flow- inpiratory flow