Chapter 88: Noninvasive Support of Respiratory Failure

INTRODUCTION

Despite its clear association with lung injury, mechanical ventilation (MV) continues to be widely practiced in many neonatal intensive care units (NICUs). Recent data suggest that trauma to the respiratory system can be avoided by gentle respiratory support initiated soon after birth. Accordingly, in the past decade there has been increasing interest in using noninvasive respiratory support with nasal continuous positive airway pressure (CPAP) or nasal intermittent positive pressure ventilation (NIPPV) for managing respiratory failure in infants, with the focus to reduce the use of MV and protect the lung. Nasal CPAP therapy has been the mainstay of noninvasive respiratory support. However, the literature reflects conflicting results on the effectiveness of nasal CPAP in infants with respiratory failure because of inconsistencies in the guidelines for CPAP therapy, use of different devices and ventilator modes, and variations in training and levels of experience with nasal CPAP use. Little attention is paid to the best ways of practicing nasal CPAP therapy.

This chapter discusses the physiological effects, indications for use, application aspects, weaning strategies, complications, and controversies of nasal CPAP therapy based on the firsthand personal experience using binasal prongs CPAP for over 3 decades. These management protocols¹ have been practiced successfully in our NICU for nearly 40 years and have been shown to reduce chronic lung disease in preterm infants without increasing morbidity or mortality. They have been increasingly adopted and practiced at many NICUs throughout the world with good results. We also provide an overview of some of the other types of noninvasive respiratory support strategies used in newborn infants.

NASAL CPAP THERAPY

The mainstay nasal CPAP is a particular form of noninvasive respiratory support that applies positive pressure to the airway of a spontaneously breathing patient throughout the respiratory cycle.

Physiological Effects

1. Increases transpulmonary pressure and functional residual capacity (FRC) and improves lung compliance.

2. Prevents alveolar collapse (atelectrauma), decreases intrapulmonary shunt, and provides progressive alveolar recruitment.

3. Conserves surfactant.

4. Prevents pharyngeal wall collapse.

5. Stabilizes the chest wall and decreases thoracoabdominal asynchrony and work of breathing.²

6. Increases airway diameter and splints the airways.

7. Splints the diaphragm.

8. Stimulates lung growth.³

9. Bubble CPAP adds high-frequency ventilation⁴ and stochastic resonance effects.⁵

Excessive CPAP pressure may lead to serious consequences, such as air leak syndromes and increased dead space ventilation, leading to a rise in PaCO₂. Furthermore, high levels of CPAP can increase intrathoracic pressure, resulting in diminished venous return to the heart and reduced cardiac output, decreased pulmonary perfusion, and enhanced ventilation-perfusion mismatch.

Indications for Nasal CPAP Therapy

Evidence has accumulated over the past 4 decades to support the use of nasal CPAP not only to facilitate weaning in intubated infants but also as a primary mode of support in infants with various types of respiratory compromise situations, ...