Protective Lung ventilation and Driving Pressures

Question 1

What is the goal of lung protective strategies in mechanical ventilation?

Answer 1

To minimize ventilator-induced lung injury (VILI) and protect the lungs from barotrauma, volutrauma, atelectrauma, and biotrauma.

Question 2

What tidal volume is recommended in lung protective strategies?

Answer 2

Tidal volume of 6 ml/kg of predicted body weight (PBW).

Question 3

Why is tidal volume calculated using predicted body weight (PBW)?

Answer 3

PBW reflects lung size and capacity more accurately than actual body weight.

Question 4

What is the recommended plateau pressure (Pplat) to prevent barotrauma?

Answer 4

Plateau pressure (Pplat) ≤ 30 cmH₂O.

Question 5

What does plateau pressure (Pplat) represent in mechanical ventilation?

Answer 5

Plateau pressure reflects the pressure needed to inflate the lungs at the end of inspiration.

Question 6

What is the purpose of applying PEEP in lung protective strategies?

Answer 6

PEEP prevents alveolar collapse at the end of expiration and reduces atelectrauma.

Question 7

What is atelectrauma in the context of mechanical ventilation?

Answer 7

Atelectrauma occurs when alveoli repeatedly collapse and reopen, causing mechanical injury.

Question 8

What is permissive hypercapnia, and why is it used in lung protective ventilation?

Answer 8

Permissive hypercapnia allows slightly elevated PaCO₂ to reduce tidal volume and lung stress.

Question 9

What are the recommended SpO₂ targets to avoid oxygen toxicity in lung protective ventilation?

Answer 9

SpO₂ targets of 88-95% to avoid oxygen toxicity and maintain adequate oxygenation.

Question 10

What is the principle of open lung ventilation?

Answer 10

Open lung ventilation focuses on recruiting collapsed alveoli and keeping them open throughout the respiratory cycle.

Question 11

How is optimal PEEP determined in open lung ventilation?

Answer 11

Optimal PEEP is determined through incremental PEEP titration or oxygenation and compliance monitoring.

Question 12

What is a recruitment maneuver in mechanical ventilation?

Answer 12

A recruitment maneuver involves applying high pressures to reopen collapsed alveoli.

Question 13

What pressures are typically applied during a recruitment maneuver?

Answer 13

Typically, pressures of 35-40 cmH₂O are applied during a recruitment maneuver.

Question 14

Why is it important to avoid disconnections from the ventilator in open lung ventilation?

Answer 14

Disconnections can cause lung de-recruitment and alveolar collapse, which must be avoided.

Question 15

How does open lung ventilation combine PEEP and tidal volume to protect the lungs?

Answer 15

Open lung ventilation combines low tidal volumes (6 ml/kg) with adequate PEEP to maintain alveolar recruitment.

Question 16

What is the formula for calculating driving pressure?

Answer 16

Driving Pressure = Plateau Pressure (Pplat) - PEEP.

Question 17

What does driving pressure represent in mechanical ventilation?

Answer 17

Driving pressure reflects the pressure needed to expand the alveoli during tidal volume delivery.

Question 18

What is the recommended driving pressure to improve outcomes in ARDS patients?

Answer 18

Driving pressure ≤ 15 cmH₂O is associated with better outcomes in ARDS patients.

Question 19

What does a high driving pressure indicate in mechanical ventilation?

Answer 19

High driving pressure indicates over-distension or poor compliance of the lungs.

Question 20

How can driving pressure be reduced during mechanical ventilation?

Answer 20

Driving pressure can be reduced by titrating PEEP, reducing tidal volume, and improving alveolar recruitment.

Question 21

What are the key components of lung protective ventilation?

Answer 21

Low tidal volume, limiting plateau pressure, adequate PEEP, and permissive hypercapnia.

Question 22

Why is it important to monitor plateau pressure and driving pressure in ARDS patients?

Answer 22

Monitoring ensures lung stress is minimized and ventilator-induced lung injury is prevented.

Question 23

How does titrating PEEP help optimize open lung ventilation?

Answer 23

Titrating PEEP optimizes alveolar recruitment, improves oxygenation, and reduces atelectrauma.

Question 24

What is the role of compliance in assessing ventilatory stress on the lungs?

Answer 24

Compliance measures how easily the lungs expand; reduced compliance indicates higher lung stress.

Question 25

What are the main goals of mechanical ventilation in ARDS management?

Answer 25

The main goals are to optimize oxygenation, reduce lung stress, and minimize ventilator-induced lung injury.

Question 26

What is driving pressure in mechanical ventilation, and how is it calculated?

Answer 26

Driving pressure is the pressure required to inflate the lungs during a tidal breath. It is calculated as: Driving Pressure = Plateau Pressure (Pplat) - PEEP.

Question 27

What does an elevated driving pressure indicate?

Answer 27

An elevated driving pressure indicates increased lung stress and poor compliance, which can lead to ventilator-induced lung injury (VILI).

Question 28

How does driving pressure behave in patients with obstructive lung disease?

Answer 28

In obstructive lung disease, driving pressure can be moderately elevated due to increased airway resistance and air trapping.

Question 29

What are examples of obstructive lung diseases where driving pressure is affected?

Answer 29

Examples include COPD, asthma, and bronchiectasis.

Question 30

Why is driving pressure often higher in obstructive lung disease?

Answer 30

Driving pressure is higher because air trapping and airflow obstruction increase lung volumes and resistance, requiring more pressure to deliver tidal volumes.

Question 31

How does driving pressure behave in patients with restrictive lung disease?

Answer 31

In restrictive lung disease, driving pressure is often markedly elevated due to poor lung compliance.

Question 32

What are examples of restrictive lung diseases where driving pressure is affected?

Answer 32

Examples include ARDS, pulmonary fibrosis, obesity hypoventilation, and pleural effusions.

Question 33

Why is driving pressure often elevated in restrictive lung disease?

Answer 33

Driving pressure is elevated because the lungs are stiff and non-compliant, requiring more pressure to deliver the same tidal volume.

Question 34

What role does lung compliance play in determining driving pressure?

Answer 34

Lung compliance measures how easily the lungs expand. Poor compliance increases the driving pressure for a given tidal volume.

Question 35

How can reducing tidal volume help in minimizing driving pressure?

Answer 35

Reducing tidal volume lowers the amount of pressure required to expand the lungs, minimizing driving pressure and lung stress.

Question 36

What is the relationship between driving pressure and patient outcomes in ARDS?

Answer 36

Lower driving pressures (≤ 15 cmH₂O) are associated with better survival in ARDS patients, as they reduce the risk of over-distension and ventilator-induced lung injury.

Question 37

What is considered a normal driving pressure in mechanical ventilation?

Answer 37

Normal driving pressure is ≤ 15 cmH₂O.

Question 38

What does a driving pressure greater than 15 cmH₂O indicate?

Answer 38

A driving pressure > 15 cmH₂O indicates increased lung stress and poor compliance, associated with worse outcomes.

Question 39

What happens to driving pressure in a recruitable lung?

Answer 39

In a recruitable lung, driving pressure can decrease with optimal PEEP, as alveolar recruitment improves compliance.

Question 40

What happens to driving pressure in a non-recruitable lung?

Answer 40

In a non-recruitable lung, driving pressure remains elevated despite increasing PEEP, as compliance does not improve.

Question 41

How does PEEP adjustment affect driving pressure in recruitable lungs?

Answer 41

In recruitable lungs, increasing PEEP can recruit collapsed alveoli, improving compliance and reducing driving pressure.

Question 42

How does PEEP adjustment affect driving pressure in non-recruitable lungs?

Answer 42

In non-recruitable lungs, increasing PEEP may over-distend already open alveoli, worsening compliance and increasing driving pressure.