Immunosuppression in pediatric critical care patients

The pediatric critical care patient not only ranges in age, size, diagnosis, and outcome but also in immunologic capability and function. The neonate, once thought to be devoid of any immunological function, is relatively immunocompetent in some areas and immature in immunologic function in other areas. The newborn's impaired immune function is a reflection of immature and inexperienced cellular interrelations rather than the absence or immature function of a single cell line. The exact time that an infant/young child's immune system becomes mature is not definitive. The maturational process of the immune system is complex and unpredictably long. Although some components of a mature immune function occur quickly following birth (for example, colonization and secretory functions of the skin and mucous membranes), other components may take years and occur sometime before the child reaches puberty (for example, adult levels of IgG, IgD, IgA, and IgE). The critically ill infant and child have both developmental aspects of immunocompromise but also the PICU situational or clinical stressors that may impede immune function. The long-term impact of the situational stressors on the development of immune system is unknown. The PICU nurse should recognize that the critically ill child is vulnerable to immunocompromise, and provide assessment and intervention to provide optimal immune function by preventing infection and promoting host defenses.