Introduction
Mechanical ventilation helps to ventilate critically ill patients. It provides life support by assisting the patients in breathing when they cannot do it independently. Mechanical ventilation, as such, is not a treatment option but acts as a supporting aid to carry on with surgeries and other treatments for a patient in an intensive care unit (ICU). Mechanical ventilation is of two types: invasive and non-invasive.
What Are the Benefits of Mechanical Ventilation?
Mechanical ventilation is beneficial in the following ways:
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Critical injury to the brain or spinal cord (nervous system injuries) makes it hard or unable for the patient to breathe. Mechanical ventilation supports breathing in such cases.
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In some critical cases, the patients remain unconscious and may require mechanical ventilation for breathing.
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Critical patients may not be able to breathe independently. Mechanical ventilation helps to deliver oxygen directly to the lungs.
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It may be tedious for the patient to take in oxygen and eliminate carbon dioxide. Mechanical ventilation helps in the easy elimination of carbon dioxide.
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Since the body requires concentrating less on the breathing mechanism, more energy can be given to infection-fighting or disease-curing means.
Why Are Advancements in Mechanical Ventilation Necessary in Critical Care?
Mechanical ventilation is associated with several risks. Therefore many advancements took place in mechanical ventilation to resolve such problems. Some of the risks associated with mechanical ventilation are as follows:
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Pneumothorax: Mechanical ventilators can lead to collapsed lung or pneumothorax. Pneumothorax is a rare condition in which the cavities of the chest wall and the lungs get filled with gas or air. The affected part of the lungs develops holes, leading to lung collapse. It is an emergency condition requiring immediate care. In severe cases, pneumothorax can lead to death.
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Infections: Tubes attached to the airways may lead to the entrance of bacteria and other organisms, leading to infections. Pneumonia is such a lung infection, and it may turn serious gradually. Pneumonia caused due to mechanical ventilation is called ventilator-associated pneumonia (VAP).
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Lung Damage: A ventilator may pressure the lungs, leading to lung damage. In addition, high oxygen concentration may also cause injuries.
What Are the Different Types of Ventilators Present?
Advancements in modern mechanical ventilators work by pushing positive pressure into the lungs. It is of two types:
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Invasive:
A tube will be fixed either through the mouth or neck airway directly to the ventilator.
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Non-invasive:
In this, a face mask is used, which is connected to the ventilator. A strap is used to hold the head tight while the air is being pushed into the lungs.
What Is the Difference Between Intubation and Ventilators?
Intubation and ventilators are associated with each other, but they are not the same. In case of intubation, an endotracheal tube is inserted into the airway, which helps the air move in and out of the lungs. In the case of ventilators, the machine helps to move the air in and out of the lungs.
What Are the Advancements in Mechanical Ventilation?
Following are some of the advancements in mechanical ventilation:
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Low Tidal Volume Ventilation (LTVV): LTVV is an invasive type of mechanical ventilation. It prevents ventilator-associated conditions in patients. Further lung damage from mechanical ventilation should be prevented in patients with acute lung injury or acute respiratory distress syndrome. Low tidal volume ventilation helps to achieve this goal. The duration of mechanical ventilation can be shortened with the help of LTVV. In critical patients undergoing surgeries, low tidal volume ventilation helps improve postoperative outcomes. In addition, it prevents the progression of existing lung conditions. 6 to 8 milliliters per kilogram predicted body weight (mL/kg PBW), and 4 to 6 mL/kg PBW is the tidal volume recommended for patients without or with acute respiratory distress syndrome, respectively.
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Pressure Support Ventilation (PSV): PSV is also called pressure support. Pressure support ventilation is a type of ventilation in which the ventilator supports the breathing initiated by the patient after presetting the pressure value. All breaths will be triggered by the patient. Pressure levels need alterations depending on the changes in the patient's effort.
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Adaptive Support Ventilation (ASV): Adaptive support ventilation is a closed-loop ventilation method. Adaptive support ventilation adjusts automatically based on the requirements of the patient. It can act as pressure-controlled ventilation and pressure-supported ventilation. Pressure-controlled breaths will be generated by the adaptive-support ventilator in patients who cannot initiate breathing.
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Positive End Expiratory Pressure (PEEP): Positive end-expiratory pressure or PEEP applied during mechanical ventilation prevents partial or complete collapse of the lungs or lung lobes, called atelectasis. Studies are still ongoing to determine the best methods to set PEEP. High intrinsic PEEP and increasing end-expiratory lung volume (EELV) or dynamic hyperinflation are the distinguishing characteristics of chronic obstructive pulmonary disease (COPD). Newer advancements in mechanical ventilation also focus on setting adequate extrinsic and intrinsic post-end-expiratory pressure.
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Volume-Assured Pressure Support Ventilation (VAPSV): Volume-assured pressure support ventilation or VAPSV combines volume-assisted ventilation and pressure support ventilation. Pressure support ventilation (PSV) is a type of mechanical ventilation that provides support to complete the breathing cycle independently initiated by the patient. In the case of volume-assured pressure support ventilation, the tidal volume will be set, reducing the patient's exertion for breathing.
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Proportional Assist Ventilation (PAV): Proportional assist ventilation orPAV is partial ventilatory support for critically ill patients. The ventilator instantaneously provides an inspiratory pressure by proportional assist ventilation, supporting the patient's effort. In this case, the pressure generated by the ventilator will be proportional to the patient’s effort.
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Intellivent- Adaptive Support Ventilation: Intellivent-ASV or Intellivent- adaptive support ventilation monitors the partial pressure of oxygen and the end-tidal pressure of carbon dioxide. It is a closed-loop ventilation. The ventilator controller will adjust the respiratory rate and tidal volume.
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Neurally Adjusted Ventilatory Assist (NAVA): Edi or the electrical activity of the diaphragm will be utilized by neurally adjusted ventilatory assist or NAVA. Edi reflects the neural respiratory drive. It is indicated in the case of acute respiratory distress syndrome and acute hypoxemic respiratory failure. Severe hypoxia (low oxygen levels in the body tissues) without hypercapnia (high blood levels of carbon dioxide) is called acute hypoxemic respiratory failure.
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Smart-Care Ventilation: Smart-care ventilation is an automatic method that stabilizes the critically ill patient’s breathing pattern. It is a knowledge-based and automated mode of ventilation. Smart care shortens the time of mechanical ventilation.
Conclusion
A patient admitted to an intensive care unit or ICU may not be capable of breathing independently. Mechanical ventilation assists them in taking up required oxygen, which is necessary for essential bodily functioning. But mechanical ventilation possesses many demerits or serves health risks. Recent advancements in mechanical ventilation focus on improving the efficiency of supportive care provided to critically ill or injured patients. It aids in reducing the risks associated with conventional methods of ventilation. In addition, it prevents the worsening of pre-existing respiratory injuries or diseases.
