Introduction:
Respiratory disorders are very common among the pediatric population. The ratio of children affected by respiratory illness is much higher than those with other functioning system disorders. They are associated with other disease processes like trauma, sepsis (chemicals released in the body to combat an infection trigger infection throughout the body ), oncologic (relating to cancer), neurologic, and gastrointestinal conditions.
Several conditions like airway complications, barotrauma (injury due to changes in pressure), and the development of ventilator-associated pneumonia (pneumonia occurring in an intubated patient 48 hours after mechanical ventilation) are all indications of intubation (a process where a tube is inserted into a patient’s trachea to keep it open) and mechanical ventilation. Further, to facilitate the synchrony of mechanical ventilation, pain-relieving agents, sedation, and neuromuscular blocking agents are administered to the patient making the process complicated and increasing the chances of adverse events.
Why To Opt For Non-invasive Ventilation?
Non-invasive ventilation is a safer alternative to intubation and mechanical ventilation to provide respiratory support. Increasing evidence is available in the literature that justifies the use of non-invasive ventilation. Historically, bilevel positive airway pressure (aids in breathing by providing different pressure for inhalation and exhalation) and continuous positive airway pressure (aids breathing by providing the same pressure for inhalation and exhalation) were the non-invasive ventilatory modes used to treat respiratory illnesses like neonatal asthma (asthma in newborns), apnea (breathing repeatedly stops and starts in sleep), pneumonia (fluid-filled lungs), and bronchiolitis (inflammation of bronchioles). New non-invasive ventilation techniques are safe and efficient respiratory support for children with respiratory failure and acute respiratory distress syndrome (collection of fluid in the lung air sacs and depriving the organs of oxygen).
The newest addition to the non-invasive ventilation technique is the high-flow nasal cannula gaining widespread popularity with its justified use. Studies and research on these techniques have shown that non-invasive ventilation can decrease the need for mechanical ventilation and intubation, reducing intensive care days and increasing patient comfort to a large extent.
What Is the Importance of Non-invasive Ventilation?
It is important to comprehend the basics of ventilation, that is, the mechanism of gas exchange between the environment and the lung alveoli (air sacs in the lungs), to appreciate the mechanism of non-invasive ventilation in respiratory disease. During inspiration and expiration, the air moves in the lungs from high to low, depending on the alveoli's pressure. This process controls the lung volume. When volume increases, pressure decreases, and the other way around. The chest walls and diaphragm contracts during inspiration and relax during expiration, their elasticity results in an altered intrapulmonary pressure. In addition, the voluntary and involuntary processes occurring in parts of the brain and the spinal cord neurologically control breathing.
In children, the diameter of the airways is small, creating resistance to airflow. Respiratory disorders in children significantly impact the normal flow of air. Obstructive lung disorders like asthma (difficulty in breathing due to an inflamed and constricted airway), pneumonia (fluid-filled lungs), and bronchiolitis (inflammation of the bronchioles); neurological disorders like increased intracranial pressure or apnea of prematurity (when prematurely born babies stop breathing for a short period of time); and neuromuscular disorders like spinal muscular atrophy (wasting and weakness of skeletal muscles) or muscular dystrophy (group of genetic disorders that cause progressive muscle weakness and loss of muscle mass) resulting in a decrease in elasticity of the chest wall are all disease conditions associated with an impaired pulmonary mechanics and flow of air. Non-invasive helps deliver positive pressure to the airway throughout the respiratory cycle through a non-invasive interface like a face mask, nasal mask, or nasal plugs, rather than an invasive media like a tracheostomy tube or an endotracheal tube.
What Are the Most Commonly Used Non-invasive Ventilation Techniques?
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The most commonly used non-invasive systems are continuous positive airway pressure (CPAP) and bilevel positive airway pressure (BiPAP).
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Continuous positive airway pressure (CPAP) has a simple mechanism. It sets an expiratory pressure that will open the lower airways depending upon the weight and age of the child. It provides a steady pressure throughout the respiratory cycle. CPAP mode can also open an upper airway when there is obstruction.
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Bilevel continuous positive pressure (BiPAP) has a mechanism more complex than CPAP. It uses two pressure settings, expiratory pressure, and inspiratory pressure. A backup rate is set in BiPAP. Therefore, non-invasive ventilation helps open the airway to maintain the lung volume and support the elasticity of the chest wall, eventually decreasing the effort of breathing and the use of accessory respiratory muscles. It also helps in oxygenation and maintaining the patency of airways.
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For providing non-invasive ventilation, an interface is required between the patient and the device. The interface may be an oronasal or nasal mask, pillows, prongs, or helmet.
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A new addition to non-invasive ventilation over the past few years is the high-flow nasal cannula (HFNC). They are mostly used in the neonatal intensive care unit (NICU). They deliver high flow rate, heated nasal cannula air at a rate of four to six-liter air flow per minute. Studies have shown that the high flow rate helps improve alveolar ventilation (exchange of gas between the alveoli and the environment) by minimizing the dead space in the nasopharyngeal cavity (airway behind the nose, just above the roof of mouth). They also provide positive airway pressure, opening the airways and overcoming upper airway obstruction. Literature shows that heated high-flow nasal cannula (HFNC) has been successfully used in premature infants and older children for ventilation in various respiratory illnesses like asthma and bronchiolitis (inflammation of the bronchioles). The pressure settings in HNFC are based on the size and age of the child and the disease process. For infants, the flow is set at approximately four to ten liters, and for older children, up to 20 liters.
What Are the Indications for Non-invasive Ventilation in Pediatric Patients?
Asthma, bronchiolitis, and pneumonia are respiratory illnesses affecting children that require hospital admission and critical care. Bilevel continuous positive pressure (BiPAP) is the mode of non-invasive ventilation used in children with obstructive lung diseases like asthma and bronchiolitis. Studies have shown that children supported with BiPAP require only a shorter duration of intensive care.
Respiratory failure (a condition where a person can not breathe on their own) and acute respiratory distress syndrome in children is treated with CPAP or BiPAP in acute respiratory failure displayed a decreased need for intubation and mechanical ventilation. Non-invasive ventilation in the post-operative period and after extubation. The non-invasive ventilation is successful for children if used soon after extubation or later if a child develops respiratory failure. Neuromuscular diseases due to long-term use of non-invasive ventilation is seen in children with neuromuscular weakness and disorders.
Conclusion:
Non-invasive ventilation in the form of continuous positive air pressure (CPAP), bilevel continuous positive pressure (BiPAP), or high flow nasal cannula (HFNC) is a safe and effective method for respiratory support in pediatric patients when compared to invasive techniques like intubation and mechanical ventilation. Constant monitoring of the child receiving ventilation is required to check for possible complications and measure the technique's efficacy. However, further studies and research are needed to document the mode's effectiveness that provides the best respiratory support and the highest level of safety.
