Most intensive care unit (ICU) doctors will use ventilation system frequently throughout their careers. They’ll be staring at the screens, making minor adjustments, discussing them, and appreciating their existence. Because ICU doctors and nurses will be spending so much time with the machines. It’s amazing how little attention the machine’s appearance receives during training.
There’s more to understanding how to operate a machine than simply turning it on and making adjustments. Understanding the fundamental components of a mechanical ventilator will aid in understanding the big picture of how to improve the doctor’s ability to operate it.
Simply put, a mechanical ventilator is a life-support machine that breathes for the patient. Breathing, or more formally, ventilation, is the process of moving air into and out of the lungs. The ventilators should be fully automated, with no human intervention necessary to program and maintain the controls and settings. The doctor can set it and forget it, according to the plan.
The patient is connected to the ventilator via a hollow tube (artificial airway) that passes through their mouth and down into their main airway, or trachea. They will continue to use the ventilator until they are able to breathe on their own. The machine ensures that the body receives enough oxygen while also removing carbon dioxide. When certain illnesses prevent normal breathing, this is necessary. There are some benefits of mechanical ventilation, which are us under;
- Because the patient’s respiratory muscles relax, they don’t have to work as hard to inhale.
- Helps the patient in obtaining adequate oxygen and removing carbon dioxide from his or her body.
- Keeps the airway stable and protects against aspiration injury.
3 different modes of the mechanical ventilation
A mechanical ventilator’s main purpose is to give the patient time to heal. When a patient is able to
breathe effectively on their own, they are usually taken off the mechanical ventilator. There are numerous modes
of ventilation that differ only slightly from one another. The following modes are available:
Assist control ventilation (ACV)
When the ventilator settles to assist control, the ventilator will support the patient with every breath it takes (that is the assist part). If the respiratory rate falls below the set rate, the ventilator will take control (control part).
If the rate is set to 12 in assist control and the patient breathes at 18, the ventilator will assist with the 18 breaths. However, if the rate falls below 8, the ventilator will take over and deliver 12 breaths per minute.
The release of breath can be either giving volume or giving pressure in assisting control of ventilation. Volume-assist control or pressure-assist control ventilation is another term for it. Because it is simple to use, assist control (volume control) is the mode of choice in the majority of intensive care units across the United States. The ventilator has four easy-to-adjust settings (respiratory rate, tidal volume, FiO2, and PEEP).
Each breath can be time-triggered (if the patient’s respiratory rate falls below the ventilator rate, the machine will deliver breaths at predetermined intervals). Alternatively, if the patient initiates a breath on its own, it is called patient-triggered. As a result, the ventilator will supplement the patient’s efforts, making assist control a very comfortable mode for the patient.
Synchronized intermittent mandatory ventilation (SIMV)
For younger patients with good respiratory function, SIMV is an excellent mode. It helps to work the respiratory muscles because patients can initiate their own breaths. However, the ventilator also provides minimum mandatory breaths.
The term “synchronized” refers to the ventilator’s ability to adjust its breath delivery in response to the patient’s efforts. The term “intermittent” refers to the fact that not all breaths aim to support at the same time. As with AC, “mandatory ventilation” means the selection of a set rate, and the ventilator will deliver these mandatory breaths every minute regardless of the patient’s respiratory efforts.
In contrast to AC, the ventilator in SIMV will only deliver the breaths that are according to the delivery rate. If the patient takes a breath faster than this, the patient will not receive full tidal volume or pressure support. Furthermore, SIMV requires more work to breathe than AC, which has a negative impact on outcomes and causes respiratory fatigue. It is preferable to keep the patient as comfortable as possible in the meantime. As a result, SIMV may not be the best mode for this.
Pressure support ventilation (PSV)
PSV is a ventilator mode that is entirely dependent on patient-triggered breaths. It is a pressure-driven mode of ventilation, as the name implies. Because the ventilator has no backup rate, all breaths are patient-triggered in this configuration. As a result, the patient must take the first breath.
The ventilator will cycle between two different pressures in this mode (PEEP and pressure support). At the end of exhalation, PEEP is the pressure that remains. The ventilator will apply pressure above PEEP to support ventilation during each breath. This means that if a patient is in PSV 10/5, he or she will receive 5 cm H2O PEEP. He’ll receive 15 cm of H2O support during inhalation (10 PS above PEEP).
There is no backup rate, this mode should not be employed in patients with a low consciousness, shock, or cardiac arrest. The patient’s effort and lung compliance will determine the tidal volumes. The most significant disadvantage of PSV is the unpredictability of tidal volumes. This can result in CO2 retention and acidosis, and also the increased work of breathing, which can cause respiratory fatigue.
If the tidal volume decreases in this setting, the ventilator will increase the pressure support to decrease the tidal volume. In order to keep the tidal volume close to the desired minute ventilation, pressure support will decrease as the tidal volume increases.
To conclude, the main idea of this post is to describe the significance of
mechanical ventilation and its different modes. Mechanical ventilation is
without a doubt a life-saving procedure. It has an impact on the lives of millions of
patients with respiratory failure all over the world. It’s also helpful for people who
have chronic, irreversible causes of respiratory failures, such as neuromuscular
disease or brain injuries.
The initial ventilator setting can vary greatly depending on the reason for
intubation and the scope of this review. Nonetheless, for the vast majority of
cases, there are a few basic settings. In a newly intubated patient, the most
common ventilator mode is AC. The AC mode offers good comfort and simple
control over some of the most important physiological parameters. There are
different things in the ventilation system that different manufacturers are looking
to make available for the patients. A protective gloves manufacturer, protective
medical equipment manufacturer, and others are looking to install their products
in the ventilation area.
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