OVERVIEW OF PEDIATRIC RESPIRATORY FAILURE
The etiology of respiratory failure in children requiring mechanical ventilation is diverse. Children may develop respiratory failure due to primary lung disease, upper airway disease, central nervous system disease, or neuromuscular disorders.
Children may require endotracheal intubation and mechanical ventilation due to upper airway obstruction. Most commonly in children this is due to (1) infections such as croup, bacterial tracheitis, epiglottitis, neck abscesses, or laryngeal papillomatosis; (2) congenital or acquired malformations such as vascular rings, laryngeal webs, subglottic stenosis, soft tissue masses, bronchomalacia, tracheomalacia, or laryngomalacia; or (3) airway trauma from previous intubations, foreign body aspiration, burn injury, or traumatic injury.1 Some of these upper airway diseases, such as the congenital malformations, are chronic. As such, infants may present with an acute exacerbation of their chronic upper airway obstruction causing respiratory failure and may be malnourished at the time of presentation. Chronic upper airway obstruction in infants can adversely affect their ability to coordinate sucking and swallowing and impede their ability to gain weight appropriately.2 Once a stable airway is established, these infants should have a comprehensive feeding plan established to help them attain catch-up growth.
The focus of this chapter will be on nutritional considerations in infants and children with respiratory failure from parenchymal lung disease. The most common cause of parenchymal lung disease requiring intubation in children is infectious pneumonitis caused by a variety of viruses and bacteria.
In a recent international epidemiologic study by the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) group, 94% of children receiving mechanical ventilation had a pulmonary illness. The most common pulmonary pathology in this population was pneumonia.3 Other causes of pulmonary illnesses seen in decreasing frequency were pulmonary edema or effusion, pulmonary dysfunction after surgery or trauma, apnea or respiratory distress, pulmonary aspiration, bronchiolitis, asthma, upper airway obstruction, and chest trauma. In this study, most (75%) of the children received conventional mechanical ventilation, while 16% received high-frequency oscillatory ventilation (HFOV) and 8.5% received noninvasive mechanical ventilation. Each mode of ventilation is characterized by unique challenges to delivering optimal nutrition and will be discussed later in this section.
The most commonly encountered viruses causing significant respiratory disease are respiratory syncytial virus (RSV), parainfluenza virus, adenovirus, and influenza. Less commonly described pathogens in children are cytomegalovirus, enterovirus, rhinovirus, measles, and human metapneumovirus.4,5 Common bacterial pathogens include Streptococcus pneumoniae, Haemophilus influenza, Staphylococcus aureus, and Mycoplasma pneumonia.4 Children with underlying chronic diseases may develop infections from gram-negative or anaerobic bacteria. Children may infrequently develop fungal infections. Immunocompromised children are at risk of opportunistic infections such as invasive pulmonary aspergillosis, pulmonary candidiasis, or Pneumocystis carinii pneumonia.4
Noninfectious causes of pediatric lung disease leading to respiratory failure include chemical pneumonitis, idiopathic interstitial lung disease, ...