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BiPAP vs CPAP: Noninvasive Mechanical Ventilation

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This study guide is loaded with helpful practice questions about Noninvasive Mechanical Ventilation. So if that’s why you’re here, then you’re definitely in the right place.

NIV, or noninvasive mechanical ventilation, is something Respiratory Therapists use and deal with on a daily basis. That it why it’s so important to learn and understand this information now, so that you can use it throughout your career. 


Not to mention, you will need to know this stuff for the exams in your classes in Respiratory Therapy School as well. And I’m confident that this study guide can help you learn everything you need to know about Noninvasive Mechanical Ventilation.

So if you’re ready, let’s go ahead and get started.

What is Noninvasive Positive Pressure Ventilation?

Noninvasive Positive Pressure Ventilation (NPPV) is medical procedure that involves the use of ventilatory support without using an invasive artificial airway such as endotracheal tube or tracheostomy tube.

During NPPV, the health care provider administers air, usually with added oxygen, through a face mask or nasal mask under positive airway pressure (external lung pressure being greater than the pressure inside of the lungs).

What are the Goals and Benefits of Noninvasive Ventilation?

Some of the primary goals of noninvasive ventilation include the following:
  • Adequate ventilation and oxygenation
  • Correction of respiratory failure
  • Adequate patient tolerance and comfort
On the other hand, noninvasive ventilation offers the following benefits:
  • Makes activities of daily living easier because it helps patients use more of their lung capacity while decreasing the breathing work load.
  • Alleviates a wide array of symptoms such as daytime fatigue, morning headaches, breathing difficulties, and other symptoms associated with low oxygen levels.
  • It reduces length of hospital stay by providing clients with adequate ventilation while preventing respiratory failure.
  • It’s more convenient compared to invasive ventilation and it’s commonly given as in-home treatment as well.
  • The treatment improves the patient’s quality of life by relieving symptoms associated with cardiopulmonary disorders.

Indications for NPPV:

Patients with difficulty of breathing may need NPPV to maintain adequate ventilation. In most cases, patients with the following medical conditions are recommended to undergo NPPV:
  • Acute respiratory failure
  • Acute severe asthma
  • Acute heart failure
  • Breathing impairment due to a spinal cord injury
  • COPD exacerbations
  • Chest wall disorders
  • Facilitation of extubation
  • Moderate acidemia (pH <7.35)
  • Moderate hypercarbia
  • Neuromuscular disease
  • Nocturnal hypoventilation
  • Obesity hypoventilation syndrome
  • Patients with breathing difficulties who are cooperative
  • Prevention of reintubation in high-risk patients
  • Restrictive thoracic diseases
  • Tachypnea

Contraindications for NPPV:

There are definitely situations in which Noninvasive Positive Pressure Ventilation isn’t indicated. Here are those contraindications:
  • Agitation or lack of cooperation
  • Cardiac arrest
  • Excessive oral and nasal secretions
  • Inability to fit the mask
  • Inability to maintain a patent airway or protect the airway
  • Recent surgical procedure involving the airway or gastrointestinal tract
  • Respiratory arrest

Complications of Noninvasive Ventilation:

Even though this medical procedure is non-invasive, it can still increase a patient’s risk for the following conditions:
  • Acute respiratory distress syndrome (ARDS)
  • Aerophagia (excessive air swallowing)
  • Airway dryness
  • Aspiration
  • Claustrophobia
  • Decreased cardiac output
  • Dry mouth
  • Eye irritation from an air leak
  • Gastric distension and insufflation
  • Pressure areas from mask, tubing and strapping
  • Secretion build up inside the mask

What are the Types of Noninvasive Positive Pressure Ventilation?

Primarily, there are two types of NPPV, and they are:
  • BiPAP – this is a spontaneous breathing mode of noninvasive ventilatory support that allows for a separate regulation of the inspiratory and expiratory pressures. 
  • CPAP – this is a method of noninvasive ventilatory support where pressure above atmospheric maintained at the airway throughout breathing. The patient must be breathing spontaneously.


Both CPAP and BiPAP have similarities with regards to the attachments such as a mask and circuit, but they have a few key differences as well.

The purpose of CPAP is to improve and support the patient’s oxygenation. CPAP does not improve the patient’s ventilatory status, so the patient must be breathing spontaneously if CPAP is in use.

BiPAP, on the other hand, can help to improve the patient’s ventilatory status. So if the patient has an elevated PaCO2, BiPAP can be administered in order to help decrease the PaCO2 back into the normal range.

Interfaces for Noninvasive Positive Pressure Ventilation:

1. Mouthpiece – This is placed between the lips of the patient and is secured by lip-seal.
2. Nasal mask – It covers the nose but not the patient’s mouth.
3. Nasal pillows – It makes use of two soft silicone pillows that are inserted into the patient’s nostrils.
4. Oronasal mask – It covers both the mouth and nose of the patient.
5. Full-face mask – It covers the patient’s mouth, nose, and eyes.

As a Respiratory Therapist, it’s important to select the proper interface in order to achieve the best clinical outcome for the patient.
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