Observational StudyPathophysiology of Anemia in PICU Survivors

In 2007, the TRIPICU trial which demonstrated the safety of tolerating anemia in critically ill children through avoidance of unnecessary red cell transfusions. This landmark study led to practice changes and a reduction in the use of red cell transfusion during PICU stay. However, although this restrictive approach appears safe in the acute setting of PICU, there is a paucity of data regarding its long-term impact on the burden of anemia at discharge. Although 98% of patients now survive their PICU stay, we and other groups have documented that around 50% of PICU admissions will be anemic at discharge. A major contributing factor may be the increasing adoption of restrictive red cell transfusion policies during the phase of ICU admission. Given that there are approximately 9000 PICU admissions/year in Canada, this represents almost 4500 children are discharged with anemia.

The causes of anemia are multifactorial, including inflammation, co-morbidities and nutritional, including iron depletion. Anemia, in particular iron deficiency anemia, is well recognized to be associated with abnormal neurocognitive development in infants and young children. Anemia can also contribute to lower exercise tolerance levels impeding children's development and quality of life.

This protocol describes a prospective observational cohort study of PICU survivors, to better understand the epidemiology of anemia at and after PICU discharge. The primary aim will be to determine the prevalence of anemia at 2 months after PICU discharge (primary aim) as well as at 6 and 12 months follow-up (secondary aim). We will evaluate the association of anemia with neurocognitive dysfunction, and quality of life (secondary aim). We will also investigate the pathophysiology of anemia after PICU discharge. We will perform blood tests on anemic patients to measure inflammatory markers as well as markers of iron deficiency (including the new biomarker hepcidin) (tertiary aim).All patients included will be followed while hospitalized in the PICU, as well as at dedicated clinics at 2, 6, and 12 months after PICU discharge.

Anemia affects a large proportion of PICU survivors. This study will allow us to better understand the long-term prevalence and causes of anemia in this population as well as potential association with long-term outcome. Anemia (specifically iron responsive anemia) could be a potentially readily modifiable risk factor, to improve the long-term well-being of these children.