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

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12 Jul 202208:07

Summary

TLDRThis 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.

Outlines

00:00

💡 Understanding Ventilator Modes: Volume Control vs. Pressure Control

This paragraph discusses the comparison between volume control and pressure control ventilation in ventilators. It explains that the concept of a ventilator is to provide positive pressure ventilation, pushing a certain volume of gas into the lungs. There are many modes of ventilators, but fundamentally, there are two methods used to deliver the desired volume: pressure control and volume control. In pressure control, the pressure is set, while in volume control, the volume is set. Both aim to deliver sufficient tidal volume to the lungs. The paragraph also explains the difference in waveforms between the two modes, with volume control delivering a constant flow until the set volume is reached, after which the machine switches to the exhalation phase. In contrast, pressure control starts with a high flow rate to reach the target volume and then maintains a relatively constant pressure during the entire inspiration phase. The paragraph also discusses the importance of measuring alveolar pressure to prevent lung injury due to excessive pressure and highlights the advantages of volume control ventilation, such as the constant production of tidal volume despite changes in airway resistance and lung compliance.

05:00

🔬 Advantages and Disadvantages of Volume Control Ventilation

The second paragraph delves into the advantages and disadvantages of volume control ventilation. It points out that volume control ventilation has the advantage of providing a constant tidal volume, which is beneficial when there are changes in airway resistance and lung compliance. However, it also has its drawbacks, such as the potential for higher airway pressure at the end of inspiration compared to pressure control, which could increase the risk of lung injury. The paragraph also mentions that with a constant inspiratory flow, there is a risk of uneven alveolar filling, leading to atelectasis and a higher risk of ventilator-associated lung injury. Furthermore, it discusses the preference for pressure control ventilation in patients who are triggering the ventilator, as it is perceived to be more comfortable due to the high initial flow rate and longer inspiratory time. The paragraph concludes by emphasizing the importance of close monitoring and regular observation of patients to ensure effective ventilation without causing harm.

Mindmap

Keywords

💡Ventilator

A ventilator is a machine that assists in breathing for patients who cannot breathe adequately on their own. In the context of the video, ventilators provide positive pressure ventilation, which means they push a certain volume of air into the lungs. The script discusses two main modes of ventilator operation: volume control and pressure control.

💡Volume Control Ventilation (VCV)

Volume Control Ventilation is a mode where the ventilator is set to deliver a specific volume of air with each breath. The script explains that in VCV, the ventilator maintains a relatively constant flow rate throughout inspiration until the set volume is reached, after which it switches to expiration. This mode ensures a constant tidal volume, which is beneficial for maintaining consistent ventilation.

💡Pressure Control Ventilation (PCV)

Pressure Control Ventilation is a mode where the ventilator is set to deliver air at a certain pressure level. Unlike VCV, the flow rate in PCV starts high at the beginning of inspiration and then decreases (decelerating flow) as the set pressure is reached. The script mentions that this mode can help prevent over-distension of the alveoli and ventilator-associated lung injury.

💡Inspiratory Flow Rate

Inspiratory flow rate refers to the speed at which air is delivered to the lungs during inspiration. The script contrasts VCV, where the flow rate is relatively constant, with PCV, where it starts high and decreases. This difference impacts the patient's comfort and the risk of lung injury.

💡Tidal Volume

Tidal volume is the volume of air that comes into and goes out of the lungs during normal breathing. The script emphasizes that both VCV and PCV aim to deliver an adequate tidal volume to the lungs. However, VCV ensures a constant tidal volume, while in PCV, the volume can be affected by changes in lung compliance or airway resistance.

💡Airway Resistance

Airway resistance is the opposition to airflow caused by the narrowing or obstruction of the airways. The script discusses how changes in airway resistance can affect the delivered volume in VCV and the pressure required in PCV. It's a critical factor in adjusting ventilator settings.

💡Compliance

Lung compliance refers to the ability of the lungs to expand and contract. The script mentions that a decrease in lung compliance can affect the volume delivered in VCV and the pressure required in PCV. Compliance is an important factor in determining the appropriate ventilator settings.

💡Overdistension

Overdistension is a condition where the alveoli are stretched beyond their normal capacity, which can lead to lung injury. The script explains that PCV can help prevent over-distension by controlling the pressure applied to the lungs.

💡Ventilator-associated Lung Injury (VALI)

Ventilator-associated Lung Injury refers to damage to the lungs caused by mechanical ventilation. The script discusses how both VCV and PCV modes have strategies to prevent VALI, such as controlling the peak pressure or using a decelerating flow pattern.

💡Invasive Mechanical Ventilation

Invasive mechanical ventilation is a form of mechanical ventilation where a tube is inserted into the patient's airway to connect the ventilator to the lungs. The script implies that both VCV and PCV can be used in invasive mechanical ventilation and discusses the importance of monitoring to prevent complications.

💡Inspiratory:Expiratory (I:E) Ratio

The I:E ratio is the proportion of time spent in inspiration compared to expiration during mechanical ventilation. The script suggests that in VCV, the I:E ratio is fixed, which can lead to uneven filling of the alveoli and a higher risk of atelectasis. In contrast, PCV allows for a longer inspiratory time, which may be more comfortable for the patient.

Highlights

Understanding the concept of ventilator machines which provide positive pressure ventilation.

There are two main methods used by ventilators to deliver the desired volume: pressure control and volume control.

In pressure control, the pressure is set, while in volume control, the volume is set.

Both methods aim to provide sufficient tidal volume to the lungs.

Volume control machines deliver air until the set target volume is reached, then transition to exhalation.

In volume control, the flow rate is relatively constant from the beginning to the end of inspiration.

Pressure control starts with a high flow rate at the beginning of inspiration and then decelerates.

Pressure control mode can help prevent alveolar overinflation and ventilator-associated lung injury.

Volume control ventilation maintains a constant flow, which can lead to higher end-inspiratory pressure compared to pressure control.

The peak pressure in volume control is influenced by the pressure needed to overcome airway resistance.

Volume control ventilation has the advantage of maintaining a constant tidal volume even with changes in airway resistance.

Pressure control ventilation is considered more comfortable for patients due to the high initial flow rate and longer inspiratory time.

In pressure control, the risk of alveolar overinflation is lower as the pressure is controlled and monitored.

Volume control ventilation may lead to uneven alveolar filling due to the constant inspiratory flow.

Pressure control ventilation allows for better patient-ventilator synchronization, especially when the patient is initiating breaths.

The key to effective ventilation is tight monitoring and regular observation of the patient, regardless of the mode chosen.

Understanding the differences between volume control and pressure control is crucial for preventing ventilator-associated lung injury.