**9. Non-invasive respiratory support**

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

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

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

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

**Lipids (%) Proteins (%) Dose (body mass)**

100–200 mg/kg (1.25–2.5 ml/kg) in suspension

50 mg/kg (1.2 ml/kg) in suspension

100 mg/kg (4 ml/kg) diluted before

use

99 SP-B, SP-C 1%

99 SP-B, SP-C 1%

88–90 SP-B, SP-C 1%

found to conclude that one of the two methods is better than the other [39].

**surfactant**

porcine lungs

bovine lungs

homogenized bovine lungs

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

liquid layer and the air in the lung alveoli [32].

**Type of surfactant Company name Origin of** 

Poractant alfa Curosurf® Extraction from

Bovactant Alveofact® Lavage from

Beractant Survanta® Extraction from

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

possible [6, 36].

52 Selected Topics in Neonatal Care

effect on the cerebral haemodynamics, is being conducted [33].

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 (CPAP), the intermittent insufflation of positive pressure (nasal intermittent positive pressure ventilation, NIPPV), which can be time determined or synchronous triggered by inhalation (synchronous nasal intermittent positive pressure ventilation (SNIPPV)) and ventilation at two levels of positive pressure (bi-level positive pressure ventilation, Bi-Level) or even with high-frequency oscillations (high-frequency oscillation ventilation (HFOV)) have been developed. Different randomized studies have explored the advantages or disadvantages of one method of non-invasive ventilatory support over the other. In comparing the non-invasive ventilation with NIPPV to the nasal CPAP, fewer respiratory failures and the need for intubation in the NIPPV group were found [46]. Meta-analysis of the use of different devices and interfaces for CPAP has elucidated differences in outcome depending on the use of nasal adapters or interfaces, requiring further research [47]. Similarly, there is an open question whether breathing with the help of bi-level CPAP is better than breathing with CPAP alone and does it pose an advantage of better exhaling CO<sup>2</sup> , better oxygenation or other physiological indicators [48].

**10. Invasive artificial ventilation of the neonate**

Nowadays, the invasive artificial ventilation of the neonate represents a continuation of treatment in cases where non-invasive ventilation with or without the use of surfactant is not possible or successful. In invasive mechanical support ventilation with a respirator, CPAP is usually supplied in combination with intermittent mandatory or synchronized artificial ventilation (i.e. intermittent mandatory ventilation (IMV); synchronized intermittent mandatory ventilation (SIMV)). Ventilation can be sustained at two different positive pressure levels (variable/bi-level positive airway pressure, bi-level (BiPAP)). Other forms of artificial ventilation include ventilation by releasing the pressure (airway pressure release ventilation (APRV)), neuronal-mediated respiratory support (neurally adjusted ventilatory assist (NAVA)), and so on. In the case of the artificial ventilation, one should always set the concentration of a mixture of the inspired oxygen and air, the frequency of the ventilation, the ratio of duration of the inspiration and expiration or time of inspiration, the end-inspiratory pressure or the tidal volume and the end-expiratory pressure. Each respirator is equipped with the heater and humidifier in order that neonates breathe moist and warm mixture of air and oxygen. In cases of severe pulmonary disease with severe RD, high-frequency oscillating ventilators, which

Respiratory Care of the Neonate

55

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

use very low inspiratory volumes that do not damage the lung tissue, may be used.

tilation can be switched to conventional artificial ventilation again [53].

High-frequency oscillation ventilation is a method of artificial ventilation, which in cases of severe RD can be the least harmful way of ensuring good oxygenation and due to the active exhalation wash out carbon dioxide as well. High-frequency oscillation ventilation will only be successful if the pulmonary alveoli are optimally opened prior to the start of oscillations. In HFO, the optimization of lung volume is achieved by small increments of continuous positive distending airway pressure and the pressure in lung alveoli. Gradually, the increase of continuous positive distending airway pressure leads to opening of the small, collapsed non-ventilated lung and by that to the increment of the FRC of the lungs that ensure good ventilation and oxygenation. Consequently, the optimally opened lung tissue is then oscillated with very small tidal gas volume (order of the neonate's dead space of the lungs), which regulates the exhalation of carbon dioxide from the lungs. Oscillations with small volumes are less harmful for the delicate lung parenchyma and do not damage it, thereby preventing the secondary injury such as barotrauma and volutrauma. When lung function improves, the neonate's ven-

The most important factor in invasive artificial ventilation of the neonate is to prevent the lung over-distension, because it injures the delicate lung tissue and causes air leakage outside the airway with the development of pulmonary interstitial emphysema (PIE), PTX or pneumomediastinum (PM) and other even more severe forms the air leakage into the chest. When lungs become more compliant, the pressure-guided artificial ventilation may lead to lung over-distension, therefore many of the neonatal respirators are programmed to the restriction of tidal volume (volume-targeted ventilation; volume-guaranteed ventilation (VGV)). Care should be taken not to cause hypocapnia during ventilation since it decreases the brain blood flow and causes periventricular leukomalacia (PVL) and IVH which jeopardize the neurological development. The volume-targeted artificial ventilation was shown to shorten the duration

If higher mean inspiratory pressures are required for the lungs to remain inflated, the potential non-invasive ventilation using HFO via nasal tubes or cannulas may be used since even long-term studies have confirmed advantages of HFO non-invasive ventilation over other invasive ventilation methods.

Ventilation of neonates using high-flow rates (high-flow nasal cannula (HFNC)) has some advantages over CPAP due to less damage to the nose and nasal septa and less pneumothorax (PTX) [49]. A multicentre study being conducted in nine centres in Australia and Norway might give answers as to which breathing support is better in very preterm infants, CPAP or HFNC [50].

Nose requires special attention because the prolonged nasal respiratory therapy may cause decubitus and malformations of the nose. Regular changes of devices and protection of the nose skin and mucosa with skin-protective strips and/or creams prevent those problems. Gastric distension has to be prevented by an opened nasogastric tube and regular checking of gastric over distension which decrease compromise of diaphragm contractions. Neonatal care in term neutral environment incubators or warm beds and preventive positions like Cocoonababy® Nest or similar home-made products besides frequent changes of neonate's positions improve ventilation during the period of acute respiratory problems. Kangaroo care is a useful method to improve bonding between the neonate and the mother or father but has to be carried out cautiously during non-invasive ventilation [51]. During kangaroo care, observations have to be made whether apnoeic spells are more frequent and whether bradycardia occurs.

Non-invasive respiratory ventilation enables non-aggressive approaches, without sedation, analgesia, tracheal intubation and mechanical ventilation. Complications of non-invasive ventilation are mainly pressure sores of skin around the nose, ulceration and necrosis of the septum, much less likely hyperinflation of the lungs, restlessness, PTX, stomach distension or food intolerance. Non-invasive ventilation failure may be predicted by the use of neonatal chest US [52].
