Basic Ventilator : Pressure Controlled vs Volume Controlled Ventilation, Mana yang Lebih Baik?

Summary

This script discusses the comparison between volume control and pressure control ventilation in mechanical ventilators. It explains that while both aim to deliver adequate breath volume to the lungs, volume control maintains a constant flow and ends inspiration once the set volume is reached, resulting in a relatively constant pressure throughout inspiration. In contrast, pressure control starts with a high flow rate that decelerates, aiming to reach the set pressure quickly. The script also highlights the importance of monitoring alveolar pressure to prevent lung injury and discusses the advantages and disadvantages of each mode, emphasizing the need for close patient monitoring to ensure effective ventilation.

Takeaways

• 🌟 The concept of a ventilator is to provide positive pressure ventilation, pushing a certain volume of gas into the lungs.
• 🔧 There are two main methods for ventilators to deliver the desired volume: pressure control and volume control.
• 📊 In volume control ventilation, the machine delivers air until the set target volume is reached, then switches to the expiratory phase, maintaining a relatively constant flow.
• 📈 With pressure control ventilation, the flow rate is high at the beginning of inspiration and then decelerates, aiming to reach the target pressure quickly.
• 🏥 Volume control ventilation ensures a constant tidal volume regardless of changes in airway resistance or patient lung compliance.
• ⚖️ Pressure control ventilation allows for constant pressure in the airway while the flow is decelerating, which can help prevent over-distension of the alveoli.
• 🚫 A drawback of volume control is the risk of higher airway pressure at the end of inspiration compared to pressure control, which could lead to barotrauma.
• 🛑 Volume control may also result in uneven alveolar filling due to the constant inspiratory flow and short inspiratory duration, potentially leading to atelectasis.
• 🌬️ Pressure control ventilation is considered more comfortable for patients due to the high initial flow rate and longer inspiratory time, reducing the sensation of air hunger.
• ⚠️ Both modes require close monitoring to adjust for changes in airway resistance or lung compliance to ensure effective and safe ventilation.
• 📉 Pressure control ventilation can be monitored by observing the pressure at the end of inspiration, which can help in preventing ventilator-associated lung injuries.

Q & A

What is the main concept of a ventilator machine?

The main concept of a ventilator machine is to provide positive pressure ventilation, meaning the machine will deliver a certain volume of gas into the lungs.

What are the two methods used by ventilators to deliver the expected volume?

The two methods used by ventilators to deliver the expected volume are pressure control and volume control.

What is the difference between pressure control and volume control ventilation?

In pressure control, the ventilator sets the pressure to be delivered, while in volume control, it sets the volume of gas to be delivered.

How does volume control ventilation affect the flow rate and pressure during inspiration?

In volume control ventilation, the machine delivers air until the set target volume is reached, then ends the inspiration phase and proceeds to expiration. The flow rate is relatively constant throughout inspiration, while the pressure increases gradually until it peaks at the end of inspiration.

What is the characteristic flow pattern of pressure control ventilation?

In pressure control ventilation, the flow rate starts high at the beginning of inspiration and then decreases (decelerating) until the target volume is reached.

Why is the peak pressure in volume control ventilation higher than in pressure control?

The peak pressure in volume control ventilation is higher because it includes the pressure needed to overcome airway resistance.

What is the advantage of volume control ventilation?

Volume control ventilation has the advantage of producing a constant tidal volume, ensuring that the patient always receives a relatively consistent volume of breaths.

What is the risk associated with using constant flow in volume control ventilation?

The risk associated with using constant flow in volume control ventilation is uneven alveolar filling due to the relatively short inspiratory duration, which can lead to atelectasis and a higher risk of injury from excessive pressure.

How can one measure the alveolar pressure during ventilation?

Alveolar pressure can be measured by performing an occlusion at the end of the inspiratory phase, which allows one to observe what is known as the alveolar pressure.

What is the main advantage of pressure control ventilation for the patient?

Pressure control ventilation is considered more comfortable for patients because of the high initial flow rate and longer inspiratory time, which reduces the sensation of air hunger and allows for better synchronization of breaths if the patient is also breathing.

What is the risk of using pressure control ventilation if there is an increase in airway resistance or a decrease in lung compliance?

The risk of using pressure control ventilation in cases of increased airway resistance or decreased lung compliance is that the patient may experience insufficient ventilation.

What is the most important aspect of using any ventilation mode?

The most important aspect of using any ventilation mode is tight monitoring and regular observation of the patient to ensure effective ventilation without causing injury.