**8. Surfactant**

Pulmonary surfactant, a macromolecular lipoprotein complex, secreted by the alveolar epithelial cells type II, reduces the surface tension in the pulmonary alveoli at the end of exhalation. Sufficient amount of surfactant in the mature lungs prevents complete collapse of the lungs at the end of exhalation. A part of the inhaled air remains to be 'trapped' in the pulmonary alveoli, what is called the FRC. In each subsequent breath, it is not necessary to re-open the lungs from the total collapse, which greatly reduces the work of breathing and with that fatigue and respiratory failure. A thin layer of a surfactant in the walls of the pulmonary alveoli at the end of each inspiration is not completely waterproof, some liquid passes through the pores being in contact with the air in the lung alveoli, increasing the surface tension and preventing the overdistension of the alveoli at the end of inspiration. The lung surfactant is rapidly adsorbed and easily distributed in the form of a thin film on the surface between the liquid layer and the air in the lung alveoli [32].

**L**ess **I**nvasive **S**urfactant **A**dministration (LISA) and **M**inimally **I**nvasive **S**urfactant **T**reatment (MIST) are other two less invasive methods of surfactant application. With LISA, the preterm neonate who is supported by CPAP via nasal prongs, the larynx is opened by laryngoscope and by the Magill forceps a thin and soft aspiration tube is inserted below the level of the vocal cords, and then the surfactant is applied in two to four aliquots while the neonate is spontaneously breathing. With MIST, the tube for surfactant application is somewhat stiffer and bent so it can be inserted into the larynx without the Magill forceps. According to the authors, MIST is an easier method for less skilled doctors [40]. To confirm the hypothesis that less invasive surfactant administration combined with the respiratory support by CPAP is more successful in neonates who have some natural surfactant and not effective in those who have too little of their own surfactant, a blind, multicentre, randomized study in premature neonates between 25 and ≤28 weeks gestation, requiring CPAP and a low percentage of

underway. The research group is being treated with poractant alpha at a dose of 200 mg/kg body weight, and the control group receives placebo [41]. None of the above-described meth-

The methods of surfactant aerosolization have up to date been more or less unsuccessful. With the **C**atheter **A**nd **L**aryngeal **M**ask **E**ndotracheal **S**urfactant **T**herapy (CALMEST) the

high positive-predictive value of a respiratory failure at 6 h after birth. Therefore, the recent recommendations suggest an early less invasive surfactant administration before the neonate requires high proportions of oxygen in the inspired air [43]. If no improvement is seen after the first dose, the surfactant application is repeated for the second or third time. In this case, the poractant alpha at a dose of 200 mg/kg body weight is supposed to have better effect as a

Late-preterm and term neonates besides rarely having a primary surfactant deficiency due to genetic defect of surfactant proteins, they more often suffer from secondary surfactant deficiency in conjunction with MAS, pneumonia and pulmonary haemorrhage. In those cases small studies have shown improved oxygenation, gas exchange and a reduced need for extra-

The best and most frequently used treatment of neonatal RD nowadays is CPAP through nasal spouts (nasal mask, nasal cannula and nasal tube) with the addition of the interfaces by using various physical processes to insufflate and exhale the mixture of air and oxygen into and out of the respiratory tract of a neonate [45]. It has been proven to reduce side effects that neonates could suffer if they were ventilated by the invasive methods of artificial ventilation. Until now, a variety of techniques applying positive pressure of constant pressure

surfactant is administered by a catheter and the laryngeal mask [42].

lower dose of poractant alpha or beractant (100 mg/kg body weight).

The oxygen requirement higher than the FiO<sup>2</sup>

corporeal membrane oxygenation (ECMO) [44].

**9. Non-invasive respiratory support**

from 0.30 to 0.45) during the first 6 h after birth, is currently

>0.3 after 2 h of breathing with CPAP has a

Respiratory Care of the Neonate

53

http://dx.doi.org/10.5772/intechopen.69674

oxygen in the inhaled air (FiO<sup>2</sup>

ods can avoid laryngoscopy.

Several animal surfactants of bovine or porcine origin are used in Europe (**Table 3**).

Currently, a double-blind study of a synthetic surfactant, CHF5633, with the same effect in the treatment of RD as poractant alpha, but a stronger anti-inflammatory and a more favourable effect on the cerebral haemodynamics, is being conducted [33].

Early publications recommended the application of surfactant in developed RD as a 'rescue' or therapeutic administration or prophylactically for the prevention of RD in very premature infants in the first few minutes after birth. Criticism of the prophylactic administration of surfactant was that likely 27–60% of preterm infants receive surfactant unnecessarily [34, 35]. Recommendation nowadays is to stabilize the respiration of a spontaneously breathing neonate by using CPAP and early selective surfactant administration. When an endotracheal intubation is needed due to progressive RD, the neonate should obtain surfactant as soon as possible [6, 36].

Another way of avoiding lung barotrauma and especially volutrauma, techniques to shorten the duration of artificial ventilation or even completely avoiding it, has been developed in recent years. The first of such methods of fast and non-invasive surfactant application was **IN**tubate— **SUR**factant—**E**xtubate (INSURE). The extubation was followed by non-invasive respiratory support [37, 38]. In comparing early INSURE method with CPAP without the administration of the surfactant, certain advantages were found in the INSURE group. Not enough evidence was found to conclude that one of the two methods is better than the other [39].


**Table 3.** Surfactants, registered for therapy of RD in Europe.

**L**ess **I**nvasive **S**urfactant **A**dministration (LISA) and **M**inimally **I**nvasive **S**urfactant **T**reatment (MIST) are other two less invasive methods of surfactant application. With LISA, the preterm neonate who is supported by CPAP via nasal prongs, the larynx is opened by laryngoscope and by the Magill forceps a thin and soft aspiration tube is inserted below the level of the vocal cords, and then the surfactant is applied in two to four aliquots while the neonate is spontaneously breathing. With MIST, the tube for surfactant application is somewhat stiffer and bent so it can be inserted into the larynx without the Magill forceps. According to the authors, MIST is an easier method for less skilled doctors [40]. To confirm the hypothesis that less invasive surfactant administration combined with the respiratory support by CPAP is more successful in neonates who have some natural surfactant and not effective in those who have too little of their own surfactant, a blind, multicentre, randomized study in premature neonates between 25 and ≤28 weeks gestation, requiring CPAP and a low percentage of oxygen in the inhaled air (FiO<sup>2</sup> from 0.30 to 0.45) during the first 6 h after birth, is currently underway. The research group is being treated with poractant alpha at a dose of 200 mg/kg body weight, and the control group receives placebo [41]. None of the above-described methods can avoid laryngoscopy.

The methods of surfactant aerosolization have up to date been more or less unsuccessful. With the **C**atheter **A**nd **L**aryngeal **M**ask **E**ndotracheal **S**urfactant **T**herapy (CALMEST) the surfactant is administered by a catheter and the laryngeal mask [42].

The oxygen requirement higher than the FiO<sup>2</sup> >0.3 after 2 h of breathing with CPAP has a high positive-predictive value of a respiratory failure at 6 h after birth. Therefore, the recent recommendations suggest an early less invasive surfactant administration before the neonate requires high proportions of oxygen in the inspired air [43]. If no improvement is seen after the first dose, the surfactant application is repeated for the second or third time. In this case, the poractant alpha at a dose of 200 mg/kg body weight is supposed to have better effect as a lower dose of poractant alpha or beractant (100 mg/kg body weight).

Late-preterm and term neonates besides rarely having a primary surfactant deficiency due to genetic defect of surfactant proteins, they more often suffer from secondary surfactant deficiency in conjunction with MAS, pneumonia and pulmonary haemorrhage. In those cases small studies have shown improved oxygenation, gas exchange and a reduced need for extracorporeal membrane oxygenation (ECMO) [44].
