Understanding shock in children

Shock is an unstable physiological state that occurs following acute failure of the circulation, which results in inadequate tissue perfusion and oxygenation and incomplete removal of harmful metabolic waste products. Shock leads to a decrease in intravascular volume, a disruption to circulating intravascular volume, or impaired cardiovascular function (Waltzman, 2015). Recognising shock can be difficult as the signs and symptoms of shock are not those of the underlying disease/process, but the body's attempts to maintain homeostasis by preserving an effective circulation (Cameron et al, 2019). If shock is not recognised, anaerobic metabolism and tissue acidosis will result; if these changes are not reversed, end organ failure will follow (Crisp and Rainbow, 2007).

In this article, ‘children’ will refer to any child or young person up to 16 years of age. However, although infection is recognised as the leading cause of mortality and morbidity in the newborn (Bedford Russell, 2015), early-onset neonatal infection will not be discussed. Shock is classified in many ways, describing the physiological response to the underlying cause. Waltzman (2015) identified the three classifications for shock as hypovolaemic, distributive and cardiogenic; Cameron et al (2019) added obstructive and dissociative to total five classifications. Although these classifications support an understanding of the underlying cause of shock, an alternative approach is to consider how the child's circulation is compromised. For an effective circulation the child requires three essential components: fluid to transport oxygen and remove metabolic waste (blood), a pump to circulate the fluid (the heart), and vessels (arteries/veins) to contain the fluid.