Ventilation

Question 1

Name the 2 methods of Ventilation

Answer 1

1. Negative Pressure ventilation
2. Positive pressure ventilation

Question 2

Describe what is meant by Negative Pressure Ventilation

Answer 2

• Rarely used in VP

1. Patient placed into sealed chamber, from neck down
2. Vaccum is generated w/in the chamber
3. Causing the thorax to expland + let air move into the lungs and down a pressure gradient

Question 3

Describe what is meant by Positive Pressure Ventilation

Answer 3

1. Fresh gas is forced into the patient’s airway, in a controlled manner
2. May be delievered manually (Bagging patient or by mechanical ventilator)

Question 4

Provide 8 indications for providing Ventilation to a patient

Answer 4

1. Thoracic surgery
2. Apnoea
3. Hypoventilation
4. Falling SpO2 levels
5. Pulmonary disease
6. Excessive anaesthetic depth
7. Opioid depression
8. Nervous system disease or Injury
   (I.e. Head injury)

Question 5

List the 6 steps involved for providing IPPV to a Labrador, following Respiratory Arrest - during anaesthesia.

Answer 5

1. Turn off vaporiser
2. Flush with 100% O2
3. Close/part close APL valve
4. Squeeze bag
5. Open valve
6. Aim for 1:2 ratio of inspiration to expiration

Question 6

What is this?

Answer 6

Mechanical Ventilator

Question 7

8..

Why may you use a Mechanical Ventilator?

Answer 7

1. When prolonged IPPV is required or anticipated
2. Patient has recieved NMBAs
3. Allow more accurate ventilation, in comparison to manual IPPV
4. Allows for pre-set RR + volume of air, for individual patient
5. The pressure of gas reaching the lungs, can be accurately controlled
6. Reduces the risk of Barotrauma (Lung trauma)
7. Allows pressure to be maintained around 10-15cm of H2O
8. Good for short duration Intensive care, for Respiratory, Head or Thoracic trauma cases

Question 8

At a basic level, what does a ventilator act as?

Answer 8

Mechanical subsitute for anaesthetists’s hands

Question 9

What should Mechanical Ventilators be adjusted to?

Answer 9

The individual patient’s:
1. BW (kg)
2. Likely TV
3. Maximum airway pressure

Question 10

What other piece of equipment can be used alongside a Mechanical Ventilator, to allow for more accurate adjustments to be made?

Answer 10

Capnograph

Question 11

4 …

What various types/forms of Mechanical Ventilator models are there?

Answer 11

1. Pressure Cycling ventilators
   * Calibrated to ensure ventilation pressure remains w/in a pre-set range.
2. Some anaesthetic machines incorperate a ventilator
3. Pressure, time or Volume sensitive cycling ventilators (Or all 3)
4. Some incoperate features to allow Humidification or Nebulisation of inspired gases
   * Great for Intensive care.
5. Some connect to a bag protector of the ana circuit
   * All attach to scavenge port in some way
   * All should be ideally compatible w/variety of anaesthetic breathing systems

Question 12

What are the 5 general rules, when using a Mechanical Ventilator?

Answer 12

1. Use a snug fit ET tube
2. Calculate the patient’s TV + calibrate accurately for the size of the patient, prior to anaesthesia
3. Set a pressure limit of 10-15cm H20 set
4. Monitoring CO2 levels, allows anaethestist to determine more effective ventilation
5. Always allow a longer expiratory phase, when setting up parameters

• As they’ll be a decrease of Intra-thoracic pressure occurs during expiration
• To allow for Venous return to the Heart

Question 13

What is the vital part to remember when weaning a patient off IPPV?
+
Why is this important?

Answer 13

They are weaned off gradually
+
Because this allows the Bronchiolar Stretch Receptors + Chemoreceptors in the hindbrain to be stimulated, initaiting independent respiration!

Question 14

What type of ventilation can be invaluable tool, yet with a users’ lack of training, its incorrect use can be potentially life-threatening to the patient?

Answer 14

Mechanical Ventilators

Question 15

What is 1 Down?

Answer 15

Valve

Question 16

What is 2 Down?

Answer 16

Tidal

Question 17

What is 3 Down?

Answer 17

Chemo

Question 18

What is 5 Down?

Answer 18

NMBA

Question 19

What is 7 Down?

Answer 19

Scavenger

Question 20

What is 9 Down?

Answer 20

Bains

Question 21

What is 11 Down?

Answer 21

Apnoea

Question 22

What is 4 Across?

Answer 22

Air

Question 23

What is 6 Across?

Answer 23

Nebulisation

Question 24

What is 8 Across?

Answer 24

Positive

Question 25

What is 10 Across?

Answer 25

Capnography

Question 26

What is the **purpose** of Ventilation?

Answer 26

**To refresh the air**, as O2 comes in + CO2 goes out

Question 27

How can Respiratory **disease** **affect** Ventilation?

Answer 27

Because: 1. Millions of **air sacs** become **clogged** w/**Pus**, **Inflammation** + **Fluid** 2. **O2 can't diffuse across into** the **bloodstream** 3. **CO2 remains** in the blood

Question 28

**How** can Mechanical **Ventilators help** patients - anatomically/**physiologically** - with Respiratory **disease**?

Answer 28

1. MVs **force air into lungs** 2. **Opening up** the patient's **air sacs**, which may be **collapsed w/Fluid** 3. **Enabling** the **lungs to exchange O2 + CO2** 4. As well as **delivering O2 at a higher rate** **than they can breathe in**

Question 29

True or False. 1. Mechanical Ventilators deliver fresh air into the lungs 2. Then pausing to circulate and allow air + CO2 to escape

Answer 29

True