What is a Ventilator?
A ventilator is a medical device that provides ventilatory support through mechanical ventilated for patients who are unable to breathe independently or whose respiratory function has failed. It helps maintain oxygen supply and carbon dioxide removal, serving as a critical device that might save the lives of critically ill patients.
By setting parameters (such as respiratory rate and tidal volume), it delivers gases into the lungs. It is used for patients requiring breathing support due to diseases, trauma, or postoperative conditions, and can sustain life either temporarily or long-term.
The medical ventilator parts include:
Main Unit: Responsible for controlling gas delivery, pressure regulation, and mode switching;
Breathing Circuit: The tubing connecting the main unit to the patient, used for delivering oxygen and compressed air;
Ventilator Screen: Shows ventilation parameters and alarm information in real time, helping healthcare personnel monitor the patient’s condition;
Interface Device: Such as a face mask, endotracheal tube, or tracheostomy tube, ensuring the effective entry of gas into the patient’s airway.
How Does a Ventilator Work?
For patients who are unable to breathe effectively, either non-invasive or invasive ventilation methods are selected based on the condition. Both methods maintain oxygen supply through positive pressure ventilation, with the key goal of matching the patient’s respiratory status, reducing complications, and supporting the recovery of the underlying disease.
Non-Invasive – With Face Mask
Non-invasive ventilation connects to the patient via a face mask or nasal mask, suitable for patients with mild to moderate respiratory distress who are conscious and possess some spontaneous breathing ability, such as during an acute exacerbation of chronic obstructive pulmonary disease.
The mask fits snugly over the mouth and nose; the ventilator provides additional air pressure during inhalation to help oxygen enter the lungs, and reduces pressure during exhalation to expel carbon dioxide. This method avoids the trauma of intubation but requires patient cooperation to prevent air leakage.
Invasive – Artificial Airway
Invasive ventilation is suitable for cases of severe respiratory failure, coma, or complete cessation of spontaneous breathing. Healthcare professionals insert an endotracheal tube through the mouth or nose into the trachea, or perform a tracheostomy to place a tube through the neck. Patients are usually given sedatives to alleviate discomfort.
The ventilator connects with the tube via a breathing circuit, actively pushing oxygen-containing gas into the lungs according to preset parameters, precisely controlling tidal volume, respiratory rate, and other factors to ensure stable ventilation.
For long-term ventilator use, a tracheostomy can reduce the risk of laryngeal injury, though it may lead to infection or airway damage.
Who Needs a Ventilator?
1.Cardiac or Respiratory Arrest
In emergency resuscitation or postoperative monitoring, when spontaneous breathing completely ceases, a ventilator must forcibly deliver air to maintain basic oxygen circulation.
2.Patients with Neuromuscular Weakness
Neurological diseases such as amyotrophic lateral sclerosis, myasthenia gravis, or high-level spinal cord injuries may lead to respiratory muscle paralysis, resulting in weak or absent spontaneous breathing.
3.Patients with Expiratory Difficulties Due to Carbon Dioxide Retention from Airway Spasm
Acute asthma attacks or allergic reactions may cause bronchospasm, impeding normal exhalation. A ventilator is needed to pressurize and open the airways to expedite the expulsion of waste gases.
4.Patients with Airway Damage
Airway structural damage caused by tracheal collapse, laryngeal edema, or severe burns and smoke inhalation necessitates intubation or tracheostomy to bypass the obstructed area and maintain oxygen supply.
5.Patients Whose Lungs Are Filled with Fluid or Secretions
In cases of drowning-induced pneumonia where alveolar fluid accumulation or infectious pus blocks normal breathing, pressurized oxygen delivery can help penetrate the liquid barrier to improve oxygenation.
What Role Does a Ventilator Play?
A ventilator assists or replaces spontaneous breathing to help maintain effective ventilation. Its primary function is to ensure that oxygen enters the lungs and carbon dioxide is expelled, adjusting airflow pressure, frequency, and other parameters to keep the airways open and improve gas exchange efficiency, while also reducing the burden on the respiratory muscles, allowing the failing respiratory system to rest temporarily.
In emergency treatment, a ventilator can provide respiratory support in situations such as cardiac arrest, severe trauma, or suffocation, buying time for rescue. For patients with short-term respiratory failure (e.g., postoperatively or due to pneumonia), it aids in overcoming the critical period and promotes the recovery of spontaneous breathing.
For patients with chronic respiratory disorders (such as amyotrophic lateral sclerosis, pulmonary fibrosis, or severe chronic obstructive pulmonary disease), a ventilator, by maintaining necessary ventilation long-term, delays disease progression, reduces the risk of complications, and, while ensuring life safety, improves the patient’s quality of life.
Different Types of Ventilators
1.According to the Power Source/Mechanism
Pneumatic (Air-driven) Ventilator
Rely on an external high-pressure gas source for power, requiring connection to fixed compressed air equipment. They provide stable gas supply and are commonly used in ICUs or operating rooms.
Turbine Ventilator
Equipped with a built-in turbine to generate pressurized air independently, without the need for an external gas source. They are compact and portable, suitable for emergency rescue, patient transport, or home use, though they tend to be slightly noisier during operation.
2.According to the Ventilation Mode
Invasive Ventilator
Establish an artificial airway through intubation or tracheostomy, suitable for critically ill patients with respiratory failure, requiring strict sterile procedures and continuous monitoring.
Non-Invasive Ventilator
- CPAP (Continuous Positive Airway Pressure) Ventilators
Provide continuous positive airway pressure via a face mask to maintain constant pressure. They are primarily used for obstructive sleep apnea (OSA) or respiratory support in preterm infants (e.g., Neo-CPAP).
- BiPAP (Bilevel Positive Airway Pressure) Ventilators
Provide two levels of pressure – inspiratory positive airway pressure (IPAP) and expiratory positive airway pressure (EPAP) – used for patients with mild to moderate respiratory failure, COPD, or neuromuscular diseases.
Invasive & Non-invasive Ventilator
Support free switching between the two modes, allowing treatment plans to be adjusted according to the patient’s condition, such as phased treatment for COVID-19 patients during the pandemic.
3.According to the Application Scenario
ICU Ventilator
Multifunctional and high-precision devices supporting various ventilation modes (such as volume control, pressure control), equipped with advanced monitoring systems, and suitable for critical care monitoring.
Emergency/Transport Ventilator
Portable and durable, with long-lasting built-in battery power and shock-resistant design, suitable for pre-hospital emergencies or long-distance transport.
Home Sleep Ventilator
Primarily CPAP or BiPAP types, user-friendly, and used long-term for the treatment of sleep-disordered breathing in a home setting.
4.According to Patient Type
Adult/Child Ventilator
With a wide range of adjustable parameters, airflow, and pressure support, covering the needs of adolescents and adults.
Neonatal Ventilator (Neo-CPAP)
Provide continuous low-pressure airflow to help keep the lungs of premature infants or neonates with weak breathing open, using a non-invasive design to reduce the risk of injury.
Risks Associated with Using a Ventilator
Infection Risk
The use of a ventilator through an artificial airway (such as an endotracheal tube) can introduce bacteria into the lungs, especially in invasive ventilation, which may lead to ventilator-associated pneumonia (VAP). Strict disinfection measures are required.
Airway Irritation or Damage
The intubation process or continuous high-pressure airflow from the ventilator may cause dryness, ulceration, or bleeding of the airway mucosa, which in severe cases can result in tracheal stenosis.
Vocal Cord Function Impairment
Prolonged intubation may compress the vocal cords, leading to vocal cord paralysis or hoarseness, with some cases requiring postoperative rehabilitation to restore function.
Worsening Pulmonary Edema
Improper ventilator pressure settings may affect intrathoracic pressure, impeding venous return and exacerbating pulmonary circulation congestion or pulmonary edema.
Risk of Thrombosis
Long-term bedridden patients combined with mechanical ventilation experience slowed blood circulation, increasing the risk of deep vein thrombosis (DVT), which could lead to pulmonary embolism.
Sedation-Related Delirium
Sedatives used to ensure patient-ventilator synchrony may induce delirium or cognitive impairment, with elderly patients being particularly sensitive.
Neuromuscular Function Degeneration
Prolonged reliance on a ventilator may lead to disuse atrophy of the respiratory muscles, making it difficult to wean off the machine, and some patients may develop peripheral nerve damage.
Risk of Fluid Overload
Positive pressure ventilation can affect renal blood flow perfusion, potentially causing water and sodium retention. Caution is needed for patients with cardiac and renal insufficiency as their condition may worsen.
Lung Barotrauma or Volutrauma
Excessively high airway pressures or tidal volumes may cause alveolar rupture (leading to pneumothorax or mediastinal emphysema) or inflammatory injuries (biotrauma).
How Long Do People Need to Use a Ventilator?
The duration of ventilator use varies by individual and requires personalized assessment. The following four core factors determine the treatment period or when to taken off ventilator:
The patient’s pre-illness health status and age
Older patients or those with comorbidities (such as heart or lung diseases) or weakened immune systems tend to recover more slowly and may require prolonged ventilatory support.
The Nature of the Underlying Disease
Acute conditions (such as pneumonia or trauma) may allow for weaning within days to weeks;
Chronic diseases (such as end-stage COPD or amyotrophic lateral sclerosis) may necessitate long-term or even lifelong reliance on a ventilator.
Treatment Response and Complications
The complexity of the condition and the presence of complications will affect the actual treatment duration, requiring dynamic adjustments by the physician.
If infection control and organ function improve rapidly, the weaning time may be shortened;
If complications such as barotrauma, VAP, or weaning failure occur, the treatment period may be prolonged.
The Treatment Goals of the Patient and Family
In irreversible disease stages, decisions on whether to continue ventilator support or switch to palliative care should consider the patient’s wishes and ethical or religious factors.