Severe Bronchiolitis as a Cause of ARDS in Early Childhood. Pathophysiology and Strategies to Minimize Lung Injury

Abstract

Bronchiolitis is one of the most frequent acute diseases of the lower respiratory tract in infants worldwide, and Respiratory Syncytial Virus remains the most common and aggressive viral disease. The course of the disease is usually benign, but its severity may change by evolving into parenchymal disease. In the more severe cases, its clinical and radiological characteristics may be consistent with acute respiratory distress syndrome. Management of these cases includes admission to paediatric intensive care and invasive mechanical ventilation. This paper reviews the definition of paediatric and neonatal acute respiratory distress syndrome, which was primarily designed and validated for adults. The article investigates the pathophysiology of paediatric acute respiratory distress syndrome further, describing how damage to the alveolar-capillary units, surfactant inactivation and inflammation occurs. Mechanisms that contribute to acute lung injury, such as volutrauma, barotrauma, stress and strain, are illustrated in detail, and an overview of the strategies that may help minimize neonatal lung injury and optimize ventilatory support is provided. These strategies include lung-protective mechanical ventilation, surfactant treatment, inhaled nitric oxide, high frequency oscillatory ventilation, recruiting manoeuvres, prone position and neuromuscular blocking agents. The objective is to help clinicians understand the peculiar pathophysiology of severe bronchiolitis and so guide them in preventing or attenuating lung injury during treatment. As such, this paper aims to contribute to defining optimal treatment of severe cases of bronchiolitis.