What Is the Difference Between NIV and NPPV?
Noninvasive positive pressure ventilation (NPPV) is the most commonly used mode of noninvasive ventilation (NIV).
Ventilation (also called mechanical ventilation) is a technique to provide breathing support to a patient who has difficulty breathing or who cannot breathe spontaneously (in the absence of ventilator support) due to various causes.
Mechanical ventilation is of two main types:
- Invasive ventilation
- Noninvasive ventilation
Invasive ventilation is a method where the air is delivered to the patient’s airways through a tube (called an endotracheal tube) inserted into the trachea.
Noninvasive ventilation provides breathing or respiratory support to a patient without the establishment of any invasive airway (such as an endotracheal tube).
Noninvasive ventilation provides air to the patient’s lungs through a well-fitted mask that can be placed over the mouth, nose, or both. It can support breathing through two broad mechanisms: negative and positive pressure ventilation.
- Noninvasive positive pressure ventilation delivers oxygen to the lungs by creating a positive pressure that forces air inside the airways.
- The positive pressure helps open the airways, thereby facilitating the delivery of oxygen to the alveoli or tiny air sacs in the lungs.
- The alveoli are the site of the exchange of oxygen and carbon dioxide between the airways and the blood.
NPPV is the preferred mode of assisted ventilation these days and may be provided in different ways, namely continuous positive airway pressure, bilevel positive airway pressure (BiPAP), and auto-adjusting positive airway pressure.
Noninvasive negative pressure ventilation is rarely used these days. It involves creating a negative pressure that sucks air into the lungs through a device that encases the chest and neck. The passive recoil of the chest wall causes exhalation.
Negative pressure ventilation was mainly used during the polio epidemic in the 20th century (commonly called iron lung).
What is NIV used for?
Noninvasive ventilation (NIV) is used for patients who have certain types of breathing problems, and who must:
- Be cooperative toward the procedure
- Have difficulty breathing or dyspnea
- Have symptoms of increased efforts while breathing (such as pursed lips while breathing or inward pulling of the muscles between the ribs, called intercostal retractions)
- Have increased breathing rate or tachypnea (more than 24 breaths per minute)
- Have certain lab findings, such as reduced blood oxygen levels or pH levels
Some of the health conditions for which NIV is used are:
- Obstructive sleep apnea
- Chronic obstructive pulmonary disease
- Congestive heart failure
- COVID-19
- Pulmonary edema
- Lung collapse or atelectasis
- Chronic bronchitis
- Pulmonary fibrosis
- Certain lung infections
- Asthma
- Postoperative respiratory distress and respiratory failure
- Do-not-intubate status (patients who have declared that invasive ventilation should not be used for them)
- Respiratory distress syndrome in infants
- Neuromuscular conditions, such as spinal muscular atrophy
- Cystic fibrosis
- Rib fractures
- Weaning from endotracheal intubation
Noninvasive ventilation cannot be used on patients who:
- Are in a coma
- Have a cardiac arrest
- Are in a respiratory arrest
- Have a condition that requires immediate intubation
What are the risks of noninvasive positive pressure ventilation (NPPV)?
The risks of NPPV include:
- Nosebleeds
- Headache
- Aspiration (entry of solids or liquids into the airways)
- Pneumonia (ventilator-associated pneumonia)
- Sinusitis
- Cough
- Runny or stuffy nose
- Sore throat
- Dry nose
- Persistent difficulty breathing
- Increased airway secretions
- Chest discomfort
- Abdominal distension or bloating
- Eye irritation
- Headache
- Skin irritation (generally caused by an ill-fitting mask)
- Airway injury or trauma