Ventilation: CPAP, BIPAP, and HFNC - CE/NCPD

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ALERT

Noninvasive ventilation (NIV) should be considered only for patients who are breathing spontaneously.

Leaks and resistance in interface devices may reduce or eliminate the machine’s ability to maintain the set pressure level.

Because of the risk of aspiration, do not restrain patients requiring a face mask on NIV. The patient should be able to remove the mask in the event of vomiting.

OVERVIEW

NIV is delivery of ventilatory support without the placement of an artificial airway (an endotracheal tube or tracheostomy); ventilatory support is provided through a nasal mask, nasal pillows, full-face mask, or helmet mask. NIV is used to prevent airway obstruction during sleep; to maintain or improve ventilation, oxygenation, or both; and to provide respiratory muscle rest in patients in whom invasive mechanical ventilation is not possible, acceptable, or desired.^{undefined#ref3">3}

Continuous positive airway pressure (CPAP) is the provision of continuous positive airway pressure throughout inspiration and expiration. Bilevel positive airway pressure (BIPAP) is the administration of two levels of airway pressure, one during inspiration and another during expiration. High-flow nasal cannula (HFNC) is an oxygen delivery system providing heated and humidified oxygen and air.¹

HFNC has been a popular form of oxygen delivery for pediatric patients and neonates but only recently has become available for adults. HFNC systems have many benefits, and they are more comfortable and better tolerated by many patients than many other systems (Table 1). They have become a popular substitute for both traditional high-flow oxygen and CPAP systems.¹ HFNC may be part of the care plan for hospice patients or patients with a “Do Not Resuscitate” order, but it should not substitute the need for formal transition to palliative care in terminally ill patients.¹

Modes of NIV include CPAP, BIPAP, and HFNC:

• CPAP does not provide inspiratory support but maintains positive airway pressure at end-expiration. Collapsed alveoli are recruited, functional residual capacity is increased, ventilation–perfusion match is improved, lung compliance is optimized, and the work of breathing is lessened.
• BIPAP provides two levels of pressure, an inspiratory positive airway pressure (IPAP), which may also be referred to as pressure support, and an expiratory positive airway pressure (EPAP). The use of regular intensive-care ventilators permits the addition of intermittent mandatory ventilation. BIPAP is commonly used with acute-care patients.
• HFNC provides a reduction in anatomical dead space and a positive end-expiratory pressure (PEEP) effect, particularly during exhalation. This PEEP effect is dependent upon cannula size, oxygen/air flow, cannula/naris ratio, and whether the mouth is open or closed.² HFNC provides a prescribed fraction of inspired oxygen (FIO₂) and a high level of heated humidity. Flows of 40 L/min are generally used, up to a maximum of 60 L/min.¹ Both the FIO₂ and the flow rate can be independently titrated.

Indications for NIV include:

• Obstructive sleep apnea (OSA)
• Acute exacerbation of chronic obstructive pulmonary disease
• Acute cardiogenic pulmonary edema
• Asthma
• Pneumonia
• Postextubation respiratory failure
• Thoracic trauma
• Palliative care and neuromuscular disorders

Absolute contraindications for NIV include:

• Respiratory arrest, apnea
• Uncontrolled vomiting
• Absence of upper-airway reflexes
• Pneumothorax (untreated)
• Acute, copious upper gastrointestinal bleeding
• Recent gastric, laryngeal, or esophageal surgery
• Facial trauma or airway trauma
• Facial burns
• Total airway obstruction

Relative contraindications for NIV include:

• Medical instability—hypotension, cardiac arrhythmias, need for vasopressors
• Agitation or lack of cooperation
• Excessive secretions
• Impaired swallow reflex
• Cardiac ischemia

An interface is the device that connects the noninvasive ventilation system to the patient’s airway.

• Nasal interfaces are the most commonly used devices in patients with chronic conditions such as OSA. Nasal interfaces include nasal masks (Figure 1) and nasal pillows (Figure 2). Nasal interfaces permit speech and feeding; however, these interfaces are also associated with greater resistance to gas flow and the potential for considerable leakage of gas from the mouth. HFNC uses specialized nasal prongs (wide-bore nasal cannula).
• Facial interfaces are the most commonly used devices in critical care clinical practice and include oronasal masks and full-face masks (Figure 3). These interfaces vary in size and the area of the face covered and are particularly useful for patients who are mouth breathers. An oronasal mask covers the mouth and nose, whereas a total face mask covers the mouth, nose, and eyes. These interfaces are associated with nasal congestion, skin breakdown, nasal and mouth dryness, and claustrophobia and should be reconsidered in patients who may begin to vomit. Full-face masks may be better tolerated and induce fewer adverse reactions, but their superiority for outcomes such as mortality has not been demonstrated.

SUPPLIES

See Supplies tab at the top of the page.

EDUCATION

• Provide developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, and overall neurologic and psychosocial state.
• Explain the procedure and equipment to the patient and family, including how to remove the mask quickly in the event of vomiting.
• Provide details about the potential sensations associated with NIV therapy (i.e., dyspnea, claustrophobia, lung inflation).
• Instruct the patient to report immediately any sudden increased difficulty in breathing and any nausea or vomiting.
• Explain to the patient and family that the patient will experience a dry mouth. Instruct the patient to drink fluids, if not contraindicated, and to keep the mouth moist to avoid dehydration from the continuous airflow.
• Teach the patient some relaxation and distraction techniques to facilitate cooperation with NIV therapy.
• Establish a method of communication in conjunction with the patient and family before initiation of ventilation. Explain that the patient will be able to speak, but that this should be minimized for optimal therapy.
• Encourage questions and answer them as they arise.

ASSESSMENT AND PREPARATION

Assessment

1. Perform hand hygiene before patient contact. Don appropriate personal protective equipment (PPE) based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
2. Introduce yourself to the patient.
3. Verify the correct patient using two identifiers.
4. Review the patient’s medical history for conditions that predispose the patient to added difficulty with ventilation and oxygenation or for facial trauma, surgery, or malformation that precludes an effective mask seal.
5. Assess the patient’s level of consciousness, level of anxiety, and ability to tolerate the procedure.
6. Assess the patient’s ability to protect the airway with an active gag and cough reflex.
7. Assess the patient’s upper airway patency, including the nasal passages.
8. Assess the patient’s cardiovascular and pulmonary status, including work of breathing.
9. Assess the patient’s vital signs and oxygen saturation.
10. Assess the patient for signs and symptoms of inadequate oxygenation and ventilation, including the presence of visible secretions in the airway, inspiratory wheezes, expiratory crackles, diminished breath sounds, tachypnea, shallow respirations, tachycardia or bradycardia, hypertension or hypotension, and hypoxemia.
11. Assess the patient’s face for pressure points that would place the patient at high risk for pressure injuries.
12. Review the management of clinically appropriate settings for alarms.

Preparation

1. Review the practitioner’s order for NIV with the respiratory therapist, including the system settings and the use of humidification and oxygen.
2. Check individual alarm signals for accurate settings, proper operation, and detectability.
3. Collaborate with the respiratory therapist regarding the appropriate type of interface, headgear, and NIV system needed for the prescribed therapy.
4. If the patient is using an NIV system from home, have the system checked by biomedical engineering.
5. Prepare the patient’s face for the interface device. Ensure that the patient’s skin is dry. Apply liquid skin barrier or a hydrocolloid dressing over bony prominences, such as the nose and cheekbones, depending on the type of interface used.

   Rationale: Inappropriate interfaces and headgear reduce the effectiveness of NIV and may increase complications and decrease compliance. Headgear is needed to stabilize the interface.

6. Set up the bedside suction equipment.

PROCEDURE

1. Perform hand hygiene and don gloves. Don additional PPE based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
2. Verify the correct patient using two identifiers.
3. Explain the procedure and ensure that the patient agrees to treatment.
4. Position the patient in an upright position, with the head of the bed elevated 30 degrees.³
5. Assist the respiratory therapist with initiating NIV as directed.
   1. Hold the interface device on the patient’s face or have the patient hold the interface device until comfortable with the sensation of NIV.

      Avoid placing the mask too high over the eyes because doing so can create a leak in the system and can cause eye irritation.

   2. Apply NIV therapy for short time periods before continuous application of the therapy to give the patient time to become accustomed to the interface device and the therapy.
   3. Set the initial settings at a low level of support. After the patient becomes comfortable with the initial settings, increase the support to the prescribed level as tolerated.
6. Assess the patient’s breathing pattern, including synchrony with the machine.

   Rationale: Assessing patterns of breathing and synchrony with the machine ensures delivery of a set pressure. Adequate support decreases a rapid and shallow breathing pattern and promotes a slower and deeper pattern.

   Report ventilatory asynchrony to the practitioner.

7. Monitor the patient’s work of breathing, oxygen saturation, and vital signs.
8. Monitor the fit of the interface and associated headgear.
   1. Check for leaks around the interface.
   2. Readjust the straps as needed.
   3. Consult with the respiratory therapist if a problem develops.
   4. If air is leaking from the patient’s mouth, use a chin strap with a nasal mask to prevent excessive leaks through the mouth.

      Rationale: An ill-fitting mask affects the delivery of adequate pressure.

9. Remain at the bedside upon initiation of the therapy to coach the patient on how to achieve ventilator synchrony and decrease the anxiety associated with NIV.
   1. Reassure the patient as needed.
   2. Assess the patient’s response to therapy.
   3. Adjust the machine settings as necessary.
10. Set and activate NIV system alarms, if present.
11. Reassess the patient at least every 30 minutes for tolerance and efficacy of NIV for the first 1 to 2 hours.³
12. Discard supplies, remove PPE, and perform hand hygiene.
13. Document the procedure in the patient’s record.

MONITORING AND CARE

1. Monitor the patient for changes in oxygenation and ventilation, including vital signs, oxygen saturation, breath sounds, breathing pattern, and work of breathing.

   Reportable conditions: Visible secretions in the airway, inspiratory wheezes, expiratory crackles, diminished breath sounds, increased work of breathing, tachypnea, shallow respirations, tachycardia or bradycardia, hypertension or hypotension, cyanosis.

2. Check for and maintain the proper fit of the patient’s NIV interface. Improperly fitting interfaces can decrease treatment compliance.² Readjust the headgear straps as needed.

   Reportable conditions: An ill-fitting interface and leaks around the interface

3. Monitor the patient for gastric insufflations and decompress the stomach as needed.

   Rationale: NIV can lead to increased gas flow to the stomach. Decompression of the stomach may be necessary.

   Reportable conditions: Gastric distention, nausea, vomiting

4. Suction the patient’s oral and nasal airways as needed.

   Rationale: Increased secretions may impede ventilation.

   Reportable conditions: Increased oral, nasal, or respiratory secretions

5. Frequently assess the patient’s skin in contact with the interface.

   Rationale: Skin should always be monitored for breakdown and especially when NIV use is prolonged or when high levels of support are being used and the masks are applied more tightly.²

   1. Pay close attention to bony prominences of face and head.
   2. Keep the skin clean and dry under the interface.
   3. Use liquid skin barrier or a hydrocolloid dressing under the interface over areas in contact with the interface.
   4. If a pressure injury occurs, assess the appropriateness of the interface. Rotation of the interface device may be required to allow pressure injuries to heal.
   5. Remove the mask every 4 to 6 hours for a few minutes if the patient can tolerate it without increasing respiratory distress.³

      Rationale: Impaired skin integrity increases the risk of infection. The bridge of the nose and the cheeks are prone to skin breakdown.

      Reportable condition: Pressure injury related to interface

EXPECTED OUTCOMES

• Improved oxygenation and ventilation
• Reduced work of breathing
• Patient–ventilator synchrony
• Absence of gastric distention
• Ability to clear secretions
• Maintenance of skin integrity
• Adequate pain and anxiety management
• Patient able to cooperate with therapy

UNEXPECTED OUTCOMES

• Aspiration
• Claustrophobia
• Decreased ability to cough and clear secretions
• Discomfort with the interface and related headgear
• Eye irritation
• Gastric insufflation and distention
• Hypercarbia
• Hyperinflation or air trapping
• Hypoxemia
• Inability to obtain adequate nutrition
• Increased or decreased blood pressure
• Increased or decreased heart rate
• Nasal congestion or dryness
• Patient–ventilation asynchrony
• Pneumothorax
• Pressure injuries
• Respiratory muscle fatigue
• Sinus or ear pain

DOCUMENTATION

• Patient’s tolerance of the procedure
• Education
• Type and size of interface
• Date and time therapy is initiated and stopped
• NIV system settings
• Skin assessment
• Cardiovascular and respiratory assessment
• Vital signs
• Unexpected outcomes and related interventions
• Pain assessment and management

REFERENCES

1. Heuer, A.J., Hilse, A.M. (2021). Chapter 42: Medical gas therapy. In R.M. Kacmarek, J.K. Stoller, A.J. Heuer (Eds.), Egan’s fundamentals of respiratory care (12th ed., pp. 906-935). St. Louis: Elsevier.
2. Piraino, T. (2021). Noninvasive respiratory support. Respiratory Care, 66(7), 1128-1135. doi:10.4187/respcare.09247
3. Williams, P.F. (2021). Chapter 50: Noninvasive ventilation. In R.M. Kacmarek, J.K. Stoller, A.J. Heuer (Eds.), Egan’s fundamentals of respiratory care (12th ed., pp. 1105-1127). St. Louis: Elsevier.

ADDITIONAL READINGS

Grasselli, G. and others. (2023). ESICM guidelines on acute respiratory distress syndrome: Definition, phenotyping and respiratory support strategies. Intensive Care Medicine, 49(7), 727-759. doi:10.1007/s00134-023-07050-7

Adapted from Johnson, K.L. (Ed.). (2024). AACN procedure manual for progressive and critical care (8th ed.). St. Louis: Elsevier.

Clinical Review: Genevieve L. Hackney, MSN, RN

Published: November 2024