Patterns of acute kidney injury and functional outcome scores in pediatric patients hospitalized with acute respiratory failure

Acute kidney injury (AKI) is diagnosed in up to 30% of children admitted to pediatric intensive care units (PICU) and is strongly associated with morbidity and mortality. In recent years, there has been an increased focus on patient-centered outcomes and quality of life among survivors of AKI. One study of pediatric sepsis patients with AKI found that AKI was independently associated with worsened functional status (FS) among survivors. The present investigation focused on functional outcomes of critically ill children with acute respiratory failure (ARF) and concurrent AKI. Objectives 1. Describe the frequency of AKI in children diagnosed with acute respiratory failure (ARF). 2. Determine association between AKI among children with ARF and worsened FS after PICU stay among survivors. Design/Methods This was a single-center retrospective study at a tertiary care PICU that included children aged 3 months-18 years admitted to the PICU from 01/2013-10/2020 with ARF requiring mechanical ventilation. ARF was defined as a primary or secondary visit diagnosis that was listed in the electronic health record (EHR) during the first three days of the index PICU admission. Children who died during the first three days of PICU admission were excluded (n=13). AKI was defined using KDIGO serum creatinine (SCr) criteria. Severe AKI was defined as AKI Stage 2/3. Pediatric Cognitive Performance Category (PCPC) and Pediatric Overall Performance Category (POPC) scores from pre-PICU baseline and PICU discharge were compared. New substantive morbidity was defined as an increase in PCPC or POPC by ≥1 point. Results The final analysis included 324 patients. Severe AKI was present in 19.7% of patients. Among survivors (92%), new substantive PCPC morbidity was seen in 8.3% of children with severe AKI, compared to 1.7% in those with no AKI. New substantive POPC morbidity was also more common in survivors with severe AKI compared to no AKI (20.8% vs 13.6%, respectively). After adjusting for age and initial illness severity (PRISM-III, excluding SCr), the association between severe AKI and new substantive functional morbidity among survivors was reduced (adjusted risk difference 5.5%; 95% CI -8.4%-19.3%). PICU mortality was higher in patients with severe AKI compared to no AKI (25.0% vs 6.9%, respectively) and this association also was slightly weakened after adjustment (adjusted risk difference 16.1%; 95% CI 4.6%-27.6%). Conclusions AKI is commonly seen in children with ARF and is strongly associated with PICU mortality. In our study, there was a suggestion that AKI also was independently associated with worsened FS at time of PICU discharge, but this result was statistically imprecise. Further research using more granular scales, such as the Functional Status Score, may be needed to better elucidate this relationship.