Nasal CPAP: Uses, Settings, Benefits, and Complications

Nasal continuous positive airway pressure, commonly called nasal CPAP, is a form of noninvasive respiratory support used primarily in newborns and premature infants who can breathe spontaneously but need help maintaining adequate lung expansion and oxygenation.

By providing continuous positive pressure throughout inspiration and expiration, nasal CPAP helps stabilize the alveoli, increase functional residual capacity, and reduce the work of breathing. It is commonly used for respiratory distress syndrome, apnea of prematurity, post-extubation support, and several other neonatal respiratory conditions.

What Is Nasal CPAP?

Nasal CPAP is a method of providing continuous positive airway pressure through a nasal interface, usually short binasal prongs or a nasal mask. The pressure remains above atmospheric pressure throughout the entire respiratory cycle, including both inspiration and expiration.

CPAP is sometimes referred to as continuous distending pressure because its primary purpose is to maintain lung and airway expansion. Unlike conventional mechanical ventilation, CPAP does not routinely provide mandatory breaths. The infant must initiate each breath and generate adequate spontaneous ventilation.

This distinction is important. CPAP can improve oxygenation and reduce the effort required to breathe, but it cannot replace an absent or severely inadequate respiratory drive. An infant with persistent apnea, progressive hypercapnia, or severe ventilatory failure may require noninvasive ventilation with assisted breaths or endotracheal intubation and mechanical ventilation.

Nasal CPAP is especially useful in newborns because they predominantly breathe through the nose. A properly fitted nasal interface allows continuous positive pressure to be delivered without placing an artificial airway in the trachea.

How Does Nasal CPAP Work?

The primary physiologic purpose of nasal CPAP is to maintain lung volume at the end of expiration. This effect influences oxygenation, pulmonary compliance, airway stability, and the infant’s overall work of breathing.

Increases Functional Residual Capacity

Functional residual capacity, or FRC, is the amount of gas remaining in the lungs after a normal passive expiration. Maintaining an adequate FRC is essential because this volume keeps alveoli available for continued gas exchange between breaths.

Premature infants are particularly susceptible to losing FRC. Their lungs may be poorly compliant because of surfactant deficiency, while their chest walls are highly compliant and provide less structural support. As a result, alveoli can collapse easily at the end of expiration.

Nasal CPAP creates positive pressure that opposes this collapse. By maintaining alveolar expansion, CPAP increases the amount of aerated lung available for oxygen exchange.

The physiologic concept behind CPAP can also be observed in infants who develop expiratory grunting. When a distressed newborn partially closes the glottis during expiration, pressure builds within the lungs and helps preserve end-expiratory volume. CPAP reproduces a similar effect continuously through an external respiratory support system.

Promotes Alveolar Recruitment

Alveoli that are collapsed or unstable contribute little or nothing to effective gas exchange. Continuous positive pressure can reopen some of these lung units and help keep them from collapsing again.

As more alveoli participate in ventilation:

• Functional residual capacity increases.
• Pulmonary aeration becomes more uniform.
• Intrapulmonary shunting can decrease.
• Ventilation and perfusion become better matched.
• Oxygenation may improve.
• The required FiO₂ may decrease.

Note: This recruitment effect is especially important in neonatal respiratory distress syndrome, in which surfactant deficiency causes widespread alveolar instability and atelectasis.

Improves Pulmonary Compliance

When the lungs contain many collapsed alveoli, greater pressure and muscular effort are required to produce an adequate tidal volume. Recruiting these alveoli and maintaining them at an appropriate resting volume may improve pulmonary compliance.

Improved compliance can allow the infant to generate a more effective tidal volume with less respiratory effort.

However, more CPAP pressure is not always better. Excessive distending pressure can overinflate the lungs. Once the lungs become overdistended, compliance may decrease, tidal volume may fall, and pulmonary blood vessels may be compressed.

Note: The goal is therefore to use enough CPAP to establish and maintain adequate FRC without creating excessive lung inflation.

Decreases the Work of Breathing

An infant with respiratory distress may use considerable energy trying to reopen unstable lung units with each inspiration. By preventing repeated alveolar collapse, CPAP can decrease the amount of pressure the infant must generate during each breath.

Clinical signs of improvement may include:

• Decreased respiratory rate
• Fewer chest retractions
• Less nasal flaring
• Reduced expiratory grunting
• Improved chest and abdominal synchrony
• More comfortable spontaneous breathing

Note: If respiratory effort increases after CPAP is raised, excessive pressure, inadequate flow, obstruction, leakage, or worsening disease should be considered.

Stabilizes the Upper Airway

CPAP also acts as a pneumatic splint for the upper airway. Positive pressure within the pharynx and hypopharynx can help prevent airway structures from collapsing during inspiration.

This effect helps explain why nasal CPAP can be useful in obstructive apnea and conditions involving unstable airways, such as tracheomalacia. By stabilizing both the airways and chest wall, CPAP can make spontaneous breathing more effective.

May Support Surfactant Function

Maintaining stable alveoli may also support more effective surfactant activity. Surfactant reduces surface tension within the alveoli and helps prevent them from collapsing.

In premature infants with respiratory distress syndrome, continuous lung recruitment may assist recovery by preserving lung volume while endogenous surfactant production improves or administered surfactant begins to work.

The combination of surfactant therapy and nasal CPAP is therefore frequently used in premature infants who can resume or maintain spontaneous breathing.

Indications for Nasal CPAP

Nasal CPAP is appropriate when an infant can breathe spontaneously but needs continuous distending pressure to improve lung volume, oxygenation, airway stability, or respiratory effort.

Respiratory Distress Syndrome

Respiratory distress syndrome, or RDS, is one of the most important indications for nasal CPAP.

RDS occurs primarily in premature infants with inadequate pulmonary surfactant. Surfactant deficiency increases alveolar surface tension, leading to alveolar collapse, low lung volumes, reduced pulmonary compliance, intrapulmonary shunting, and hypoxemia.

Common findings include:

• Tachypnea
• Subcostal or intercostal retractions
• Nasal flaring
• Expiratory grunting
• Decreased breath sounds
• Cyanosis
• Low lung volumes on chest radiography
• Diffuse reticulogranular or ground-glass appearance
• Air bronchograms

Early nasal CPAP can help maintain alveolar recruitment while allowing the premature infant to continue breathing spontaneously.

A typical initial pressure for neonatal RDS is approximately 4 to 6 cm H₂O. Pressure and FiO₂ are then adjusted according to the infant’s respiratory effort, oxygenation, blood gases, and overall clinical condition.

Some infants improve with CPAP alone, while others require surfactant or progression to mechanical ventilation.

Prematurity

Premature infants are particularly likely to benefit from nasal CPAP because of their immature lungs, compliant chest walls, unstable alveoli, and increased susceptibility to atelectasis.

CPAP may be used shortly after birth in spontaneously breathing premature infants to establish and maintain lung volume while avoiding unnecessary invasive mechanical ventilation.

Early CPAP does not eliminate the need for intubation in every infant. Extremely premature infants and those with severe RDS may still develop respiratory failure requiring greater support.

Post-Extubation Support

Nasal CPAP is commonly used following removal of an endotracheal tube. An infant may have improved enough to no longer require mandatory ventilation but may still have unstable alveoli, residual lung disease, increased respiratory effort, or a tendency to develop apnea.

CPAP allows positive airway pressure to continue without maintaining an artificial airway.

When transitioning from invasive ventilation, the initial CPAP pressure may be similar to the PEEP level being used immediately before extubation, depending on the infant’s condition and clinical protocol.

Apnea of Prematurity

Apnea of prematurity is another important indication. Premature infants may experience recurrent episodes in which breathing stops long enough to produce oxygen desaturation or bradycardia. Caffeine is commonly used to reduce these episodes.

If apnea continues despite appropriate medical management, nasal CPAP at approximately 4 to 6 cm H₂O may help by maintaining airway patency and stabilizing the respiratory system.

Frequent apnea that persists despite CPAP and caffeine may indicate the need for nasal intermittent positive-pressure ventilation or invasive mechanical ventilation.

Other Indications

Nasal CPAP may also be considered for conditions such as:

• Atelectasis
• Transient tachypnea of the newborn
• Obstructive apnea
• Tracheomalacia
• Laryngeal malacia
• Bronchopulmonary dysplasia
• Viral bronchiolitis
• Viral or bacterial pneumonia
• Aspiration pneumonia
• Meconium aspiration syndrome
• Pulmonary edema
• Congestive heart failure
• Pulmonary hemorrhage
• Hemidiaphragm paralysis

Note: Clinical findings such as worsening tachypnea, paradoxical chest movement, suprasternal or substernal retractions, grunting, nasal flaring, and cyanosis may support the use of CPAP when the infant continues to ventilate adequately.

Nasal CPAP and Surfactant Therapy

Surfactant replacement is frequently associated with CPAP management in premature infants with RDS. One traditional strategy is known as INSURE, which stands for intubation, surfactant administration, and extubation. The infant is briefly intubated, receives surfactant, and is then extubated to nasal CPAP as soon as adequate spontaneous breathing is established.

Other strategies involve beginning with early CPAP and giving surfactant selectively when respiratory distress becomes more severe. An increasing oxygen requirement, worsening work of breathing, recurrent apnea, or clinical progression of RDS may indicate the need for surfactant or additional ventilatory support.

Following surfactant administration, lung compliance can improve rapidly. This change requires careful monitoring because a CPAP level that was appropriate before surfactant may become excessive after the lungs become easier to inflate.

Contraindications for Nasal CPAP

Because CPAP relies on spontaneous ventilation, it should not be used as the sole respiratory support for an infant who cannot maintain adequate breathing.

Important contraindications include:

• Poor or absent respiratory drive
• Persistent central apnea
• Severe cardiorespiratory instability
• Significant bradycardia or hypotension
• Severe hypercapnic respiratory failure
• Untreated pneumothorax or significant pulmonary air leak
• Choanal atresia
• Cleft palate
• Tracheoesophageal fistula
• Preoperative congenital diaphragmatic hernia
• Severe respiratory depression caused by medications
• Certain neuromuscular disorders that prevent adequate ventilation

Note: Congenital diaphragmatic hernia deserves particular attention because positive pressure before surgical management can worsen gastrointestinal distention within the thorax. CPAP may have a role after repair depending on the infant’s clinical condition.

Recognizing Nasal CPAP Failure

CPAP should not be continued simply to avoid intubation when the infant is clearly deteriorating. One of the most important responsibilities during nasal CPAP therapy is recognizing when the infant requires a higher level of respiratory support.

Progressive hypercapnia is a major concern. A PaCO₂ rising above approximately 60 mm Hg in combination with a pH below about 7.25 suggests that spontaneous ventilation is no longer adequate.

Severe hypoxemia despite substantial respiratory support is another warning sign. Failure should be considered when the infant continues to have a PaO₂ below approximately 50 to 60 mm Hg despite an FiO₂ of roughly 0.60 or greater and CPAP pressures approaching approximately 8 to 10 cm H₂O.

Other signs of CPAP failure include:

• Increasing work of breathing
• Worsening retractions
• Increasing nasal flaring
• Progressive respiratory fatigue
• Recurrent cyanosis
• Frequent apnea
• Apnea associated with bradycardia
• Persistent apnea despite caffeine
• Rapid clinical deterioration
• Inability to maintain adequate oxygen saturation
• Worsening respiratory acidosis

Note: Before concluding that CPAP itself has failed, the system should be evaluated carefully. Inadequate pressure delivery caused by leakage, obstruction, poor positioning, insufficient flow, or incorrect prong size can make effective therapy appear unsuccessful.

Nasal CPAP Interfaces

The interface is one of the most important components of the CPAP system because the prescribed pressure cannot be maintained without an adequate connection between the infant and the circuit.

Short Binasal Prongs

Short binasal prongs are the most commonly used neonatal CPAP interface. The prongs should fit snugly enough to minimize leakage without putting excessive pressure on the nares or nasal septum.

Prongs that are too small can produce excessive leakage and inadequate pressure. Oversized or poorly positioned prongs may cause tissue injury, erosion, bleeding, or excessive dilation of the nares. Correct sizing and secure fixation are therefore essential.

Nasal Masks

Soft nasal masks are another option. They can provide an effective seal while avoiding direct pressure inside the nostrils. However, masks can also create pressure injuries at contact points on the nose and face. Leakage around the eyes may occur if the mask is poorly positioned.

Some neonatal CPAP systems allow clinicians to alternate between nasal prongs and masks to reduce prolonged pressure on one area.

Nasopharyngeal Tubes

A nasopharyngeal tube may occasionally be used. This interface resembles a shortened endotracheal tube inserted through a nostril into the nasopharynx. It is used less commonly than binasal prongs or masks but may provide access for suctioning when secretion removal is required.

Types of Nasal CPAP Systems

Several devices can generate continuous positive airway pressure. Although they share the same fundamental goal, their mechanisms differ.

Ventilator-Generated CPAP

A neonatal mechanical ventilator can be used to provide nasal CPAP. Traditional ventilator CPAP systems use continuous gas flow and an exhalation valve to maintain the selected pressure. Modern neonatal ventilators may use variable flow and automatically adjust flow or valve position in response to patient demand.

Potential advantages include:

• Integrated oxygen blending
• Airway-pressure monitoring
• High- and low-pressure alarms
• Leak compensation
• Respiratory graphics
• Apnea monitoring
• Backup ventilation on some devices

Note: Another practical advantage is that the ventilator is already present if the infant deteriorates and requires invasive support.

Bubble CPAP

Bubble CPAP is a relatively simple constant-flow system. The expiratory limb of the breathing circuit is submerged beneath water. The depth of the tubing beneath the water surface determines the approximate CPAP pressure.

For example, placing the expiratory limb 5 cm beneath the water produces approximately 5 cm H₂O of CPAP.

Gas continuously exits through the submerged tubing, creating visible bubbling. This bubbling confirms flow through the system and produces small pressure oscillations that may be transmitted through the infant’s chest.

A typical flow of approximately 5 to 10 L/min, often around 6 to 10 L/min depending on the system and infant, may be used to meet inspiratory demand and maintain continuous bubbling. The water level must be monitored because evaporation, condensation, or movement of the tubing can change the effective pressure.

Infant Flow CPAP

Infant Flow systems use a variable-flow generator positioned near the nasal interface. During inspiration, flow is directed toward the infant. During expiration, the flow pattern is redirected away from the infant, allowing exhaled gas to escape with relatively little resistance.

The system can also entrain additional gas when the infant’s inspiratory demand increases. This design is intended to maintain more stable airway pressure and reduce the amount of work the infant must perform against the CPAP system.

Depending on the device and interface, a flow near 8 L/min may generate approximately 5 cm H₂O of CPAP when the system is properly fitted.

Initial Nasal CPAP Settings

Neonatal CPAP is commonly started at approximately 4 to 6 cm H₂O. The exact starting pressure depends on the infant’s gestational age, respiratory condition, previous ventilator support, work of breathing, and oxygenation.

FiO₂ is adjusted according to the infant’s oxygenation requirements rather than increased unnecessarily.

When a continuous-flow system such as bubble CPAP is used, flow is commonly set around 5 to 10 L/min and adjusted as necessary to maintain the desired pressure and meet inspiratory demand.

Pressure should generally be adjusted gradually, often in increments of 1 to 2 cm H₂O. The objective is to use the lowest pressure that produces adequate recruitment, acceptable oxygenation, and improved respiratory effort without causing overinflation.

Monitoring an Infant on Nasal CPAP

Successful CPAP therapy requires continuous assessment of both the patient and the equipment.

Important parameters include:

• Heart rate
• Respiratory rate
• Blood pressure
• Oxygen saturation
• Skin color
• Breath sounds
• Chest movement
• Chest and abdominal synchrony
• Nasal flaring
• Retractions
• Expiratory grunting
• Activity and alertness
• Airway pressure
• FiO₂
• Nasal and septal condition
• Secretions
• Abdominal distention
• Carbon dioxide when available
• Periodic blood gas measurements

Oxygen saturation targets vary according to gestational age, clinical condition, and institutional protocol. In neonatal care, targets are commonly maintained within a relatively narrow range to provide adequate oxygenation while avoiding unnecessary oxygen exposure.

Blood gases are useful when significant adjustments are made or when the infant’s clinical status changes. After a CPAP adjustment, enough time should be allowed for the infant to stabilize before evaluating the full response.

An improving infant typically demonstrates less tachypnea, fewer retractions, decreased grunting, better chest movement, stable oxygenation, and acceptable carbon dioxide and pH. A rising PaCO₂ or worsening oxygenation after pressure is increased may suggest excessive distending pressure and overinflation.

Troubleshooting Nasal CPAP

Loss of pressure does not always mean that the prescribed CPAP needs to be increased. A sudden decrease in measured airway pressure should prompt inspection of the system.

Possible causes include:

• Circuit disconnection
• Incorrectly positioned prongs
• Excessive leak around the interface
• Open mouth
• Insufficient gas flow
• Nasal obstruction
• Condensation in the circuit
• Malfunction of the pressure-generating system

If airway pressure decreases significantly during inspiration, the flow may be inadequate to meet the infant’s inspiratory demand. Flow can be increased cautiously after leaks and other system problems have been excluded.

An open mouth can create a substantial leak during nasal CPAP. A pacifier or carefully applied chin support may sometimes help reduce the leak.

Nasal secretions can partially obstruct the prongs or upper airway and increase the infant’s work of breathing. Adequate humidification and appropriate secretion management are therefore essential.

With bubble CPAP, clinicians should confirm that continuous bubbling is present and that the expiratory limb remains at the correct depth beneath the water.

Humidification and Circuit Management

Gas delivered during neonatal CPAP should be adequately warmed and humidified. Warm humidified gas helps protect the airway mucosa, maintain secretion mobility, and improve patient comfort. Neonatal systems are designed to provide gas near body temperature with high humidity.

The breathing circuit should be lightweight and positioned so that it does not pull on the nasal prongs or mask. Excessive tension from the tubing can create nasal pressure injuries even when the interface itself is correctly sized.

Condensation should be removed appropriately because accumulated water can increase circuit resistance, interfere with pressure delivery, or reach the patient. A pressure-relief or pop-off mechanism should protect against excessive airway pressure.

Complications of Nasal CPAP

Although nasal CPAP avoids many of the risks associated with endotracheal intubation, it can still cause clinically important complications.

Nasal and Facial Injury

Pressure injury is among the most common problems.

Possible complications include:

• Nasal irritation
• Redness
• Ulceration
• Bleeding
• Septal erosion
• Columellar injury
• Tissue necrosis
• Facial pressure injury

Note: Frequent inspection, proper sizing, careful fixation, and alternating interface types when appropriate can reduce these problems. Protective dressings may be used around vulnerable pressure points when clinically indicated.

Gastric Distention

Positive pressure can enter the esophagus and stomach, resulting in abdominal distention. The abdomen may become enlarged and intestinal loops may appear dilated on radiographs. Severe distention can push the diaphragm upward and potentially interfere with breathing.

An orogastric tube is commonly inserted when nasal CPAP is initiated so accumulated gas can be vented or aspirated.

Pneumothorax and Other Air Leaks

Excessive pressure or lung overdistention can cause pulmonary air leaks.

Possible complications include:

• Pneumothorax
• Pulmonary interstitial emphysema
• Pneumomediastinum
• Pneumatocele

The risk may increase after surfactant administration because pulmonary compliance can improve rapidly.

A sudden deterioration in an infant receiving CPAP should therefore raise concern for pneumothorax, especially when accompanied by worsening oxygenation, asymmetric chest movement, decreased breath sounds, or cardiovascular instability.

Hemodynamic Effects

Excessive intrathoracic pressure can interfere with venous return to the heart and potentially decrease cardiac output. Blood pressure, heart rate, perfusion, and overall cardiovascular status should therefore be monitored when CPAP pressures are increased.

Other Potential Effects

Positive pressure has also been associated with decreased urine output, reduced glomerular filtration, and increased intracranial pressure in some circumstances.

These effects reinforce the importance of avoiding unnecessary pressure and continually assessing whether the selected CPAP level is producing more benefit than risk.

Weaning From Nasal CPAP

Weaning can begin when the underlying respiratory condition is improving, work of breathing has decreased, apnea is controlled, and oxygen requirements are falling. In many cases, FiO₂ is reduced first toward the lowest concentration that maintains the desired oxygen saturation. CPAP pressure can then be decreased gradually.

Pressure is commonly reduced by approximately 1 to 2 cm H₂O at a time.

Depending on the infant and clinical protocol, CPAP may be discontinued once pressure has been reduced to approximately 3 to 5 cm H₂O, with some protocols weaning to approximately 2 to 4 cm H₂O before removal.

Possible withdrawal approaches include:

• Gradually reducing CPAP and then discontinuing it
• Removing CPAP once predefined stability criteria are reached
• Transitioning to heated humidified high-flow nasal cannula
• Transitioning to conventional oxygen therapy when appropriate

Repeated cycling between periods on and off CPAP is another strategy, although complete discontinuation once the infant meets appropriate stability criteria may allow a more efficient transition in some cases.

After CPAP is removed, the infant should continue to be monitored for increased work of breathing, oxygen desaturation, tachypnea, apnea, or other signs that additional support is still required.

Nasal CPAP vs. High-Flow Nasal Cannula

High-flow nasal cannula is frequently used in neonatal respiratory care and may sometimes be considered as an alternative to CPAP or as a method of support during weaning. Unlike CPAP, which directly regulates airway pressure, high-flow therapy is adjusted primarily by changing gas flow.

The amount of positive airway pressure generated by a high-flow nasal cannula varies according to the flow rate, size of the cannula, infant’s airway anatomy, and amount of leakage around the nares. The exact airway pressure therefore cannot be controlled as directly as it can with CPAP.

High-flow therapy may be easier to apply and can reduce nasal injury in some infants, but it should not automatically be considered equivalent to CPAP in every clinical situation.

Nasal CPAP vs. Nasal Intermittent Ventilation

Nasal intermittent ventilation provides more respiratory support than simple CPAP. It combines positive end-expiratory pressure with intermittent positive-pressure breaths. It can therefore be thought of as adding ventilatory assistance to the continuous distending pressure provided by CPAP.

This approach may be useful when an infant has recurrent apnea or requires more ventilatory support but clinicians are still attempting to avoid endotracheal intubation.

Simple CPAP remains appropriate when spontaneous ventilation is adequate and the primary problem involves lung volume, airway stability, or oxygenation. Once ventilatory failure develops, a mode that provides assisted breaths may be required.

Nasal CPAP Practice Questions

1. What is nasal continuous positive airway pressure?
Nasal CPAP is a form of noninvasive respiratory support that maintains positive airway pressure throughout inspiration and expiration while the infant breathes spontaneously.

2. Why is nasal CPAP also called continuous distending pressure?
It is called continuous distending pressure because positive pressure is maintained in the airway throughout both phases of the respiratory cycle.

3. Does nasal CPAP routinely provide mandatory breaths?
No. Nasal CPAP does not routinely provide mandatory breaths, so the infant must generate spontaneous ventilation.

4. What is the primary purpose of nasal CPAP?
The primary purpose of nasal CPAP is to maintain lung expansion and prevent alveolar collapse at the end of expiration.

5. How does nasal CPAP affect functional residual capacity (FRC)?
Nasal CPAP increases functional residual capacity by keeping more alveoli open at the end of expiration.

6. Why is maintaining FRC especially important in premature infants?
Premature infants often have poorly compliant lungs and highly compliant chest walls, which make them more susceptible to alveolar collapse and loss of lung volume.

7. What natural breathing behavior in distressed infants resembles the effect of CPAP?
Expiratory grunting resembles CPAP because it generates positive expiratory pressure that helps preserve end-expiratory lung volume.

8. How does nasal CPAP improve alveolar recruitment?
Nasal CPAP helps reopen collapsed or unstable alveoli and prevents them from repeatedly collapsing during expiration.

9. How does improved alveolar recruitment affect intrapulmonary shunting?
Improved alveolar recruitment decreases intrapulmonary shunting by increasing the amount of aerated lung participating in gas exchange.

10. How does nasal CPAP improve ventilation-to-perfusion matching?
Nasal CPAP improves ventilation-to-perfusion matching by recruiting lung units and creating a more uniform distribution of ventilation.

11. How can nasal CPAP improve pulmonary compliance?
Nasal CPAP can improve pulmonary compliance by recruiting collapsed alveoli and maintaining the lungs at a more appropriate volume.

12. How can nasal CPAP reduce the work of breathing?
By preventing repeated alveolar collapse and improving lung compliance, nasal CPAP allows the infant to generate tidal volume with less respiratory effort.

13. What can happen if excessive CPAP pressure causes lung overdistention?
Excessive CPAP can decrease tidal volume, reduce pulmonary compliance, compress pulmonary blood vessels, and interfere with gas exchange.

14. How does nasal CPAP affect airway resistance?
Nasal CPAP can decrease airway resistance by splinting unstable or collapsible airways open.

15. Why can nasal CPAP help treat obstructive apnea?
Nasal CPAP increases pressure within the upper airway and helps prevent the tongue and other soft tissues from causing airway collapse.

16. What is one of the principal neonatal diseases treated with nasal CPAP?
Respiratory distress syndrome is one of the principal neonatal diseases treated with nasal CPAP.

17. Why is nasal CPAP useful in neonatal respiratory distress syndrome?
It helps stabilize surfactant-deficient alveoli, increase FRC, reduce atelectasis, improve oxygenation, and decrease the work of breathing.

18. How may nasal CPAP be used after extubation?
Nasal CPAP may provide continued distending pressure after removal of the endotracheal tube to maintain lung volume and reduce the risk of respiratory deterioration.

19. What are some clinical signs that may indicate a need for nasal CPAP?
Clinical signs include tachypnea, retractions, paradoxical chest movement, expiratory grunting, nasal flaring, and cyanosis in an infant who can still ventilate spontaneously.

20. What is a common initial nasal CPAP pressure for neonatal respiratory distress?
A common initial nasal CPAP pressure is approximately 4 to 6 cm H₂O.

21. What is the most commonly used interface for neonatal nasal CPAP?
Short binasal prongs are the most commonly used interface for neonatal nasal CPAP.

22. Why is correct nasal prong sizing important during CPAP therapy?
Prongs that are too small can cause excessive leakage and inadequate pressure, while oversized or poorly positioned prongs can injure the nasal tissues.

23. Why is an orogastric tube commonly inserted during nasal CPAP therapy?
An orogastric tube is used to decompress the stomach because positive airway pressure can cause swallowed gas and gastric distention.

24. What blood gas findings can indicate that nasal CPAP is failing to provide adequate ventilation?
A PaCO₂ above approximately 60 mm Hg with a pH below about 7.25 can indicate inadequate ventilation and the need for greater respiratory support.

25. What are some important complications of nasal CPAP?
Important complications include nasal injury, gastric distention, lung overdistention, pneumothorax, other pulmonary air leaks, and possible hemodynamic effects from excessive positive pressure.

26. What is bubble CPAP?
Bubble CPAP is a constant-flow system in which the expiratory limb is submerged beneath water to generate the desired level of continuous positive airway pressure.

27. How is the pressure level determined in a bubble CPAP system?
The approximate CPAP level is determined by how deeply the expiratory limb is submerged beneath the water surface.

28. What does continuous bubbling indicate in a bubble CPAP system?
Continuous bubbling indicates that gas is flowing through the system and exiting through the submerged expiratory limb.

29. What flow range is commonly used with neonatal bubble CPAP?
A humidified gas flow of approximately 6 to 10 L/min is commonly described for meeting inspiratory demand and maintaining the selected pressure.

30. Why must the water level in a bubble CPAP system be monitored?
Changes in the water level from evaporation, condensation, or displacement can alter the pressure delivered to the infant.

31. What may cause CPAP pressure to fall significantly during inspiration?
A significant pressure drop during inspiration may indicate that gas flow is inadequate to meet the infant’s inspiratory demand.

32. What is Infant Flow CPAP?
Infant Flow CPAP is a variable-flow system that uses a generator near the nasal interface to help maintain relatively stable airway pressure during spontaneous breathing.

33. How does an Infant Flow system respond during expiration?
During expiration, the system redirects incoming gas away from the infant so exhaled gas can leave with relatively little resistance.

34. What is one advantage of variable-flow CPAP systems?
Variable-flow systems can better accommodate changes in the infant’s inspiratory flow demand and may reduce the imposed work of breathing.

35. What is one advantage of ventilator-generated nasal CPAP?
Ventilator-generated CPAP provides monitoring, alarms, blended gas delivery, and rapid access to mechanical ventilation if the infant deteriorates.

36. What equipment components are required for a complete neonatal CPAP system?
A complete system includes a gas source, oxygen blending, humidification, a breathing circuit, an airway interface, pressure monitoring, and appropriate safety mechanisms.

37. Why should the CPAP breathing circuit be lightweight and flexible?
A lightweight flexible circuit reduces pulling and pressure on the infant’s nose and helps prevent interface-related tissue injury.

38. Why is heated humidification important during nasal CPAP?
Heated humidification helps protect the airway mucosa, maintain secretion mobility, and improve comfort during continuous gas flow.

39. What is the purpose of a pressure-relief or pop-off device in a CPAP system?
A pressure-relief device protects the infant from exposure to dangerously excessive airway pressure.

40. What should be assessed when an infant suddenly loses CPAP pressure?
The clinician should check for circuit disconnection, interface leakage, an open mouth, inadequate flow, nasal obstruction, and improper prong positioning.

41. How can an open mouth affect nasal CPAP therapy?
An open mouth can create a large oropharyngeal leak that reduces the amount of pressure maintained in the airway.

42. What may be used to help reduce an oral leak during nasal CPAP?
A pacifier or gently applied chin support may sometimes be used to help reduce leakage through the mouth.

43. Why should nasal secretions be monitored during CPAP therapy?
Secretions can partially obstruct the nasal passages or prongs, increase airway resistance, and increase the infant’s work of breathing.

44. What congenital abnormality involving the nasal airway is a contraindication to nasal CPAP?
Choanal atresia is a contraindication because it can prevent effective delivery of pressure through the nasal passages.

45. Why is severe central apnea a contraindication to CPAP alone?
Severe central apnea indicates inadequate respiratory drive, and CPAP cannot provide the mandatory breaths needed to maintain ventilation.

46. What oxygenation findings may suggest nasal CPAP failure?
Persistent severe hypoxemia despite an FiO₂ of approximately 0.60 to 0.70 and substantial CPAP pressure may indicate the need for intubation and mechanical ventilation.

47. What is the INSURE approach in premature infants with respiratory distress syndrome?
INSURE involves intubation, surfactant administration, and rapid extubation to nasal CPAP rather than continuing prolonged invasive ventilation.

48. Why must CPAP pressure be reassessed after surfactant administration?
Surfactant can rapidly improve lung compliance, so a previously appropriate CPAP level may become excessive and cause overdistention.

49. How is nasal intermittent mandatory ventilation different from nasal CPAP?
Nasal intermittent mandatory ventilation adds assisted positive-pressure breaths, whereas simple nasal CPAP provides continuous pressure without routinely delivering mandatory breaths.

50. When may nasal intermittent ventilation be considered instead of simple CPAP?
It may be considered when an infant needs more ventilatory assistance because of recurrent apnea or inadequate ventilation but clinicians are still attempting to avoid intubation.

51. What oxygen saturation range is commonly targeted during neonatal CPAP therapy?
A commonly described SpO₂ target is approximately 88% to 95%, although the exact goal depends on gestational age, clinical condition, and institutional protocol.

52. What PaO₂ range may be targeted in a neonate receiving CPAP?
A PaO₂ of approximately 60 to 70 mm Hg may be targeted while avoiding unnecessarily high oxygen levels.

53. Why should excessive PaO₂ levels be avoided in premature infants?
Excessive oxygen exposure can increase the risk of oxygen-related complications, including retinopathy of prematurity.

54. How should CPAP pressure generally be adjusted when oxygenation remains inadequate?
CPAP pressure can be increased gradually in increments of approximately 1 to 2 cm H₂O while the infant’s response is reassessed.

55. Why is it useful to change only one CPAP parameter at a time?
Changing one parameter at a time makes it easier to determine whether the adjustment improved or worsened the infant’s condition.

56. How long should clinicians generally wait after a CPAP adjustment before obtaining an arterial blood gas?
At least approximately 10 minutes should generally be allowed for stabilization before obtaining an arterial blood gas.

57. What is a commonly described maximum CPAP pressure for a neonate?
A CPAP pressure of approximately 10 cm H₂O is commonly described as an upper limit for neonatal therapy.

58. What may happen to tidal volume if CPAP pressure becomes excessive?
Tidal volume may decrease because excessive pressure can overdistend the lungs and make effective spontaneous ventilation more difficult.

59. How can tachypnea contribute to unintended additional positive pressure during CPAP?
A very rapid respiratory rate can shorten expiratory time, causing gas trapping and inadvertent positive end-expiratory pressure.

60. Why can pneumothorax risk increase after surfactant administration?
Surfactant may rapidly improve lung compliance, allowing the lungs to inflate more easily while the existing CPAP pressure remains unchanged.

61. What pulmonary air leak can occur when air escapes into the lung interstitial tissues?
Pulmonary interstitial emphysema can occur when air leaks from the alveoli into the surrounding lung tissues.

62. What is pneumomediastinum?
Pneumomediastinum is the presence of escaped air within the mediastinum and is a possible complication of positive airway pressure.

63. How can excessive CPAP affect venous return?
Excessive intrathoracic pressure can reduce venous return to the heart and potentially decrease cardiac output.

64. How can nasal CPAP affect renal function?
Positive pressure may decrease renal blood flow, urine output, and glomerular filtration in some infants.

65. How can excessive positive airway pressure affect intracranial pressure?
Excessive positive airway pressure may increase intrathoracic pressure and contribute to an increase in intracranial pressure.

66. What is a nasal mask used for during neonatal CPAP?
A nasal mask provides an alternative interface for delivering continuous positive pressure without placing prongs inside the nostrils.

67. Why might clinicians alternate between nasal prongs and a nasal mask?
Alternating interfaces can reduce prolonged pressure on one area of the nose or face and may help prevent tissue injury.

68. What problem can occur if a nasal CPAP mask leaks near the eyes?
Leaking gas can irritate the eyes and indicates that the mask seal or position may need adjustment.

69. What gas temperature is described for adequately heated neonatal CPAP humidification?
Inspired gas temperatures of approximately 37°C to 39°C are described with high levels of humidification.

70. Why is adequate humidification especially important for secretions?
Adequate humidification helps prevent airway secretions from becoming thick and difficult to remove.

71. What should a low-pressure alarm detect during nasal CPAP?
A low-pressure alarm should identify significant loss of airway pressure caused by problems such as leakage or circuit disconnection.

72. What does a CPAP pressure that suddenly falls to zero usually suggest?
A sudden fall to zero commonly suggests a circuit disconnection or a major loss of the patient-device seal.

73. What is the purpose of an oxygen analyzer in a neonatal CPAP system?
An oxygen analyzer monitors the delivered oxygen concentration and helps identify when the FiO₂ differs from the prescribed level.

74. What findings suggest that an infant is responding favorably to nasal CPAP?
Improvement may include a lower respiratory rate, fewer retractions, less grunting, improved chest movement, stable oxygenation, and acceptable blood gases.

75. When is weaning from nasal CPAP generally considered?
Weaning is generally considered when respiratory distress has improved, oxygen requirements are decreasing, apnea is controlled, and the infant remains clinically stable.

76. To what pressure range may nasal CPAP be reduced before discontinuation?
Nasal CPAP is often reduced to approximately 2 to 4 cm H₂O before it is discontinued, depending on the infant’s condition and clinical protocol.

77. Which parameter is often reduced first when an infant is improving on nasal CPAP?
FiO₂ is often reduced first as oxygenation improves, followed by gradual reductions in CPAP pressure.

78. How much can CPAP pressure typically be reduced during each step of weaning?
CPAP pressure can generally be reduced by approximately 1 to 2 cm H₂O at a time while the infant is reassessed.

79. What support may be used after an infant is weaned from nasal CPAP?
The infant may transition to a heated humidified high-flow nasal cannula, oxygen hood, or conventional low-flow nasal cannula, depending on the clinical situation.

80. How does high-flow nasal cannula differ from nasal CPAP?
High-flow nasal cannula is adjusted primarily by changing gas flow, whereas nasal CPAP directly controls and maintains a selected airway pressure.

81. Why is the airway pressure generated by high-flow nasal cannula less predictable than with CPAP?
The pressure produced by high-flow nasal cannula varies with flow rate, cannula size, airway anatomy, and the amount of leak around the nares.

82. What high-flow nasal cannula flow range has been described for some neonates?
Flow rates of approximately 2 to 8 L/min have been described for neonatal high-flow nasal cannula therapy.

83. What is one potential advantage of high-flow nasal cannula compared with nasal CPAP after extubation?
High-flow nasal cannula may produce less nasal trauma in some premature infants while still providing effective post-extubation respiratory support.

84. Why should a high-flow nasal cannula not completely occlude an infant’s nares?
A tight-fitting cannula can reduce leak and allow unexpectedly high positive airway pressure to develop.

85. What is the purpose of an orogastric tube during CPAP-related gastric decompression?
The orogastric tube allows swallowed or insufflated gas to escape from the stomach and helps reduce abdominal distention.

86. How can severe abdominal distention interfere with respiration?
A distended abdomen can push the diaphragm upward and make lung expansion more difficult.

87. What advantage does a nasopharyngeal tube offer as a CPAP interface?
A nasopharyngeal tube can provide a route for passing a suction catheter when airway secretion removal is needed.

88. How should a nasopharyngeal tube be selected for CPAP?
The largest tube that can be inserted easily without causing trauma is generally selected.

89. How are neonatal CPAP prongs or masks commonly secured?
They are commonly secured with a bonnet, cap, or similar fixation system that keeps the interface positioned without excessive pressure.

90. Why is congenital diaphragmatic hernia a contraindication to CPAP before surgical repair?
Positive pressure can increase gastrointestinal distention within the thorax and further compromise lung expansion in an unrepaired congenital diaphragmatic hernia.

91. Can CPAP be considered after surgical repair of congenital diaphragmatic hernia?
Yes. CPAP may be considered after surgical repair when clinically appropriate and when the infant can maintain adequate spontaneous ventilation.

92. Why may nasal CPAP be useful in tracheomalacia?
Positive airway pressure can help splint the weakened tracheal walls open and reduce dynamic airway collapse.

93. How can nasal CPAP help an infant with pulmonary edema?
By increasing functional residual capacity and stabilizing alveoli, CPAP can improve oxygenation in infants with pulmonary edema who are still breathing spontaneously.

94. Why may nasal CPAP be used in transient tachypnea of the newborn?
CPAP can help maintain lung expansion and improve oxygenation while the infant’s transient respiratory difficulty resolves.

95. What respiratory support finding before extubation may indicate that an infant is ready to transition to CPAP?
An infant whose mandatory ventilator rate has been reduced to approximately 4 to 12 breaths/min with acceptable ventilation and oxygenation may be considered for extubation to CPAP.

96. How may the initial post-extubation CPAP level be selected?
The initial CPAP level may be set near the PEEP level that was being used immediately before extubation.

97. Why should emergency ventilation and intubation equipment remain available at the bedside during nasal CPAP?
An infant can deteriorate rapidly or develop apnea, severe hypoxemia, or another complication that requires immediate escalation to mechanical ventilation.

98. What effect may the oscillations created by bubble CPAP have on the infant?
The pressure oscillations may be transmitted to the chest and have been proposed to contribute to improved gas exchange.

99. Why may nasal CPAP be less effective in extremely small premature infants?
Very small infants, particularly those weighing approximately 1000 to 1200 g or less, may have severe respiratory immaturity and may require more support than CPAP alone can provide.

100. What is the overall goal of nasal CPAP therapy in a spontaneously breathing infant?
The overall goal is to provide enough continuous distending pressure to maintain lung volume, improve oxygenation, reduce respiratory effort, and avoid unnecessary invasive ventilation without causing overdistention or delaying needed mechanical support.

Final Thoughts

Nasal CPAP provides continuous distending pressure that helps premature and term infants maintain functional residual capacity, stabilize alveoli and airways, improve oxygenation, and reduce respiratory effort while continuing to breathe spontaneously.

Effective therapy depends on appropriate patient selection, correct interface sizing, adequate humidification and flow, careful pressure adjustment, and continuous monitoring for improvement or deterioration.

Clinicians must also recognize complications such as nasal injury, gastric distention, lung overinflation, and pneumothorax. Most importantly, worsening hypercapnia, severe hypoxemia, recurrent apnea, or progressive respiratory distress should prompt consideration of more advanced ventilatory support.