RAM Cannula Versus Short Bi-nasal Cannula in Respiratory Distress Syndrome

In the past years endotracheal intubation and mechanical ventilation with surfactant therapy was the standard treatment of moderate to severe respiratory distress syndrome (RDS). Especially in the last 10 years, prolonged intubation and positive pressure ventilation have been shown to increase the frequency of bronchopulmonary dysplasia, a kind of chronic pulmonary disease. Intubation and positive pressure ventilation cause volu-trauma, baro-trauma, and alveolar secondary to bio-trauma, leading to excessive distension and inflammation, disrupting alveolar formation, resulting in fibrosis and bronchopulmonary dysplasia. Intubation and mechanical ventilation also involve ventilator-associated pneumonia. For this reason, strategies for lung protective ventilation have become increasingly widespread in recent years and noninvasive ventilation (NNV) applications without endotracheal intubation have become the first choice in neonatal ventilation.

Noninvasive ventilation defines methods of providing ventilation support with constant or variable pressure using nasal or nasopharyngeal interfaces without endotracheal intubation or tracheostomy. Noninvasive ventilation can be performed in a variety of forms such as continuous positive airway pressure (NCPAP) nasal intermittent positive-pressure ventilation (NIPPV) and high-flow nasal cannulae.

Different nasal interfaces are used to provide noninvasive ventilation support. For this purpose, there is no standard apparatus used in neonatal intensive care units (NICU). Nasopharyngeal cannulae are not currently recommended for use with NIV because they cause extensive resistance during spontaneous breathing, nasopharyngeal area damage and colonization, although they have been widely used in previous years. Today, short binasal prongs and different types of nasal masks are the most commonly used nasal interfaces in the NICU with the aim of providing NIV. Nasal interfaces are recommended to be placed on the surface without causing pressure loss. For this purpose, hoods and fixing apparatus are frequently used. For this reason, babies often become restless and agitated during NIV applications. In addition, necrosis and deformities may develop in septum due to pressure of nasal septum.

RAM cannula (Neotech ™, Valencia, CA), a new nasal interface, is increasingly used in NID applications in newborn infants. RAM seems ideal to allow effective and cranium development in the prevention of pressure damage to the face due to the design of the cannula and the need for head or face access to detect it. The RAM cannula is available in the inspiration and expiration arms of the stroke while reducing the dead space in the respiratory tract due to the low nasal prong diameter. Although the use of RAM cannula as a NIV interface in newborn intensive care units is becoming increasingly widespread, the number of studies related to RAM cannula is limited. Most of the studies investigating the effectiveness of this interface were made on artificial lung models. In the study of "Mukerji" and colleagues, the short binasal prong and RAM cannula were compared as interfaces in NIPPV application in the artificial lung model and it was found that carbon dioxide excretion in short binasal prongs was better than RAM cannula with an increase in peak inspiratory pressure. Studies conducted by Iyer and colleagues in the artificial lung model show that RAM leakage rates below 30% lead to adequate pressure transfer to the cannulae, while leakage rates above 50% reduce pressure transfer to the lungs. Similar results have also been found in the work of "Gerdes" et al. A number of studies have been conducted on the clinical use of RAM as a noninvasive ventilation interface and in these studies it has been shown that the use of RAM cannula as an interface in NCPAP, NIPPV or even nasal high frequency ventilation applications to provide NIV is not well tolerated and does not cause gastric perforation or nasal septum damage. In the study of "Nzegwu" et al. It has been shown that in two-thirds of the patients who were treated with RAM cannula and NIV support, the respiratory support was successfully cut off. Nevertheless, none of these studies compared the RAM cannula activity with the other binasal prongs or nasal masks. Investigators compared the effectiveness (rates of surfactant therapy application, rates of intubation, total NIV duration) and nasal injury rates of RAM cannula and short binasal prong as NIV interfaces in preterm infants at neonatal intensive care unit.

Considering the studies made in the artificial lung models of RAM cannulas, which are becoming increasingly widespread in the NICUs, because of their simple and simple design and easy connection to the standard circuits of the ventilators without any intervention, investigators think that the effectiveness of NIV application is insufficient compared to the short binasal cannula.