The high-flow nasal cannula (HFNC) is a non-invasive ventilatory support that provides ventilation and oxygenation in an air flow greater than that generated spontaneously, also delivering humidified and heated air at temperatures close to 36.5ºC with a programmed fraction of inspired oxygen. At first, HFNC emerged as an alternative to replacing CPAP (continuous positive airway pressure) in preterm infants. For a better understanding and safe clinical application, it is extremely important to search for its real physiological effects for use in the Neonatal Intensive Care Unit.

To review in the current literature what are the physiological effects of usinga high-flow nasal cannula when applied to preterm infants.

This is an integrative literature review, in which scientific articles from journals indexed in the Bireme and Pubmed library and in the Scielo and PEDro databases, published between 2012 and 2022 were used.; published in Portuguese, English and Spanish, whose objective was to investigate the effects of HFNC in newborns with less than 37 gestational weeks.

Six articles were selected that fit the inclusion criteria and that update knowledge about the physiological effects. Beneficial effects such as improved oxygenation and respiratory rate, lower incidence of injury to the nasal mucosa, effective alveolar ventilation, increased pulmonary pressure, washing of the nasopharyngeal dead space and possible harmful effects such as pneumothorax, pneumo-orbitis, pneumocephalus, subcutaneous emphysema, apnea, and bradycardia.

It is concluded that the use of a high-flow nasal cannula in preterm infants has beneficial effects and is a safe resource if used through individualized prescription. Most of the research compares it with CPAP, and when performing this comparison, it was observed in most studies that it reduces the risk of nasal trauma, facilitates ventilatory mechanics and provides greater comfort. However, it has been analyzed that flow rates greater than 8 liters per minute can have negative effects. It is essential that further research be carried out to understand the physiological effects of this therapy, providing an increasingly safer practice.

When planning ventilatory support for premature newborns, one of the main concerns that the physiotherapist must pay attention to is the risks that may arise. HFNC has been gaining notoriety in hospitals, especially after its use in the Covid-19 pandemic, and researching it in depth, investigating its implications in the body, whether or not it favors adequate development of the newborn is necessary. In short, when researching the subject, professionals working in the Neonatal Intensive Care Unit will be able to have a clear understanding of the repercussions on the physiological system with the use of this therapy.