Infant CPAP Therapy Overview & Function

How Does CPAP Work?

CPAP therapy delivers a mixture of heated and humidified air and oxygen and generates a continuous distending pressure throughout the respiratory cycle by means of a sealed interface.^1,2

Selecting an appropriately-sized interface is important for achieving an adequate seal. Short bi-nasal prongs or a nasal mask are the most commonly used types of interfaces for delivering CPAP.³

Bubble CPAP, a mode of CPAP therapy, may offer an additional benefit to patients in that it generates pressure oscillations which may improve gas exchange and carbon dioxide (CO₂) elimination.⁴An underwater seal is created by submerging the expiratory tube in a variable depth of water. Gas exiting the expiratory tube produces bubbles that then generate pressure oscillations.¹CPAP can be used in both the acute and recovery phases of respiratory distress syndrome (RDS).^5,6

There are several, well-documented benefits and mechanisms of action associated with this therapy.

Maintains functional residual capacity (FRC)

CPAP enhances lung volume recruitment and helps establish and maintain adequate FRC.^1,7,8

FRC is the volume of air that remains in the lungs following a typical expiratory phase. This volume is important for keeping the lungs open post exhalation. CPAP has been shown to increase the volume of air remaining in the lungs after a typical expiratory phase, helping to keep the lungs open.^1,7

As early as the 1970s, CPAP was shown to restore FRC, improve hypoxemia, reduce pulmonary vascular resistance, and conserve surfactant.^9,10

Reduces the work of breathing

CPAP therapy can improve the work of breathing by reducing the energy required to expand the lungs for breathing.^7,11,12

Work of breathing is the force required to expand the lungs against their elastic properties. CPAP has been shown to elevate end-expiratory lung volume, which helps to unload the inspiratory muscles and reduce the work of breathing.^7,11,12

CPAP Reduces the need for mechanical ventilation

Decreases the need for invasive ventilation

The use of CPAP alone, or CPAP in combination with surfactant when used as a mode of primary respiratory support, has been associated with a reduced need for intubation and invasive ventilation.^13,14

Invasive ventilation can be lifesaving, especially for preterm infants born less than 30 weeks’ gestation with respiratory distress syndrome (RDS); however, it may contribute to increased rates of chronic lung disease. The associated disadvantages of invasive ventialtion have led to the development of more noninvasive ventilation strategies such as CPAP therapy.³ Research has shown that CPAP can be used as an alternative to routine intubation and invasive ventilation in neonates with RDS.^15,16

Bubble CPAP generates pressure oscillations

Pressure oscillations generated during bubble CPAP therapy produce vibrations that are similar to high-frequency ventilation and may improve gas exchange and CO₂ elimination.⁴

Studies have demonstrated that these pressure oscillations are transmitted down the airways and into the lungs.^4,17

CPAP can be used in neonates with RDS

Randomized controlled trials and systematic reviews have evaluated the use of CPAP as primary and postextubation respiratory support for premature and low-birth-weight neonates with RDS, in both in the acute and recovery phases of this condition. ^3,5,6

In premature infants, RDS is the most common respiratory condition that CPAP has been used for since the 1970s.^18,19 Several studies, which include randomized controlled trials and systematic reviews, have evaluated the use of CPAP as a mode of respiratory support in preterm neonates and infants with RDS. This research shows that CPAP is an effective mode of respiratory support for neonates with RDS.^3,13,20-22

Promotes airway hydration

During CPAP therapy, continuous distending pressure is generated throughout the respiratory cycle, and a heated and humidified mixture of air and oxygen is delivered.

Heated and humidified gas is an important aspect of delivering CPAP therapy, assisting with the natural defense mechanisms, maintaining airway mucosa and mucociliary function and promoting conservation of energy for growth and development.^23,24

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Gupta, S. & Donn, S. M. Seminars in Fetal and Neonatal Medicine - Continuous positive airway pressure: Physiology and comparison of devices. Semin. Fetal Neonatal Med. 21, 204–211 (2016). View abstract here.
Courtney, S. E. & Barrington, K. J. Continuous positive airway pressure and noninvasive ventilation. Clin. Perinatol. 34, 73–92, vi (2007). View abstract here.
Sweet, D. G. et al. European consensus guidelines on the management of respiratory distress syndrome – 2019 update. Neonatology 115, 432–450 (2019). View abstract here.
Lee, K. S., Dunn, M. S., Fenwick, M., & Shennan, A. T. A comparison of underwater bubble continuous positive airway pressure with ventilator-derived continuous positive airway pressure in premature neonates ready for extubation. Biol. Neonate 73, 69–75 (1998). View abstract here.
Chan, V. & Greenough, A. Randomized trial of methods of extubation in acute and chronic respiratory distress. Arch. Dis. Child. 68, 570–2 (1993). View abstract here.
Morley, S. L. Non-invasive ventilation in paediatric critical care. Paediatr. Respir. Rev. 20, 24–31 (2016). View abstract here.
Magnenant, E. et al. Dynamic behavior of respiratory system during nasal continuous positive airway pressure in spontaneously breathing premature newborn infants. Pediatr. Pulmonol. 37, 485–491 (2004). View abstract here.
Bhutani, V. K. Development of the Respiratory System. In: Manual of Neonatal Respiratory Care 3–15 (Springer US, 2012). doi:10.1007/978-1-4614-2155-9_1. https://www.springer.com/gp/book/9783319398372
Saunders, R. A., Milner, A. D., & Hopkin, I. E. The effects of continuous positive airway pressure on lung mechanics and lung volumes in the neonate. Biol. Neonate 29, 178–186 (1976). View abstract here.
Milner, A. D., Saunders, R. A., & Hopkin, I. E. Effects of continuous distending pressure on lung volumes and lung mechanics in the immediate neonatal period. Biol. Neonate 31, 111–115 (1977). View abstract here.
Diblasi, R. M. Nasal continuous positive airway pressure (CPAP) for the respiratory care of the newborn infant. Respir. Care 54, 1209–1235 (2009). View abstract here.
Higgins, R. D., Richter, S. E. & Davis, J. M. Nasal continuous positive airway pressure facilitates extubation of very low birth weight neonates. Pediatrics 88, 999–1003 (1991). View abstract here.
Finer, N. N. et al. Early CPAP versus surfactant in extremely preterm infants. N. Engl. J. Med. 362, 1970–1979 (2010). View abstract here.
Tooley, J. & Dyke, M. Randomized study of nasal continuous positive airway pressure in the preterm infant with respiratory distress syndrome. Acta Paediatr. 92, 1170–1174 (2003). View abstract here.
De Paoli, A. G. Nasal CPAP for neonates: what do we know in 2003? Arch. Dis. Child. - Fetal Neonatal Ed. 88, 168F–172 (2003). View abstract here.
Morley, C. & Davis, P. Continuous positive airway pressure: current controversies. Curr. Opin. Pediatr. 16, 141–145 (2004). View abstract here.
Hough, J. L. et al. Effect of body position on ventilation distribution in preterm infants on continuous positive airway pressure. Pediatr. Crit. Care Med. 13, 446–451 (2012). View abstract here.
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Gregory, G. A., Kitterman, J. A., Phibbs, R. H., Tooley, W. H., & Hamilton, W. K. Treatment of the idiopathic respiratory-distress syndrome with continuous positive airway pressure. N. Engl. J. Med. 284, 1333–1340 (1971). View abstract here.
Morley, C. J. et al. Nasal CPAP or intubation at birth for very preterm infants. N. Engl. J. Med. 358, 700–708 (2008). View abstract here.
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De Paoli, A. G., Davis, P. G., Faber, B., & Morley, C. J. Devices and pressure sources for administration of nasal continuous positive airway pressure (NCPAP) in preterm neonates. Cochrane database Syst. Rev. CD002977 (2008). View abstract here.
Pollett, H. F. & Reid, W. D. Prevention of obstruction of nasopharyngeal CPAP tubes by adequate humidification of inspired gases. Can. Anaesth. Soc. J. 1977 Sep;24(5):615–617 (1977). View abstract here.
de Klerk, A. In: Physiology of Humidification in Critically Ill Neonates. Springer Berlin Heidelberg (2012). https://link.springer.com/chapter/10.1007/978-3-642-02974-5_30

CPAP Therapy Overview

Continuous Positive Airway Pressure (CPAP)

How Does CPAP Work?

CPAP therapy delivers a mixture of heated and humidified air and oxygen and generates a continuous distending pressure throughout the respiratory cycle by means of a sealed interface.^1,2

Maintains functional residual capacity (FRC)

Reduces the work of breathing

Decreases the need for invasive ventilation

Bubble CPAP generates pressure oscillations

CPAP can be used in neonates with RDS

Promotes airway hydration

View references

CPAP Therapy Overview

Continuous Positive Airway Pressure (CPAP)

How Does CPAP Work?

CPAP therapy delivers a mixture of heated and humidified air and oxygen and generates a continuous distending pressure throughout the respiratory cycle by means of a sealed interface.1,2

Maintains functional residual capacity (FRC)

Reduces the work of breathing

Decreases the need for invasive ventilation

Bubble CPAP generates pressure oscillations

CPAP can be used in neonates with RDS

Promotes airway hydration

View references

CPAP therapy delivers a mixture of heated and humidified air and oxygen and generates a continuous distending pressure throughout the respiratory cycle by means of a sealed interface.^1,2