Z. Diltz3,4, R. A. Devine4, K. Wheeler4, J. Shi4, H. Xiang4, R. Fabia1,5, M. W. Hall2,4,6, R. K. Thakkar1,4,5 1Nationwide Children’s Hospital,Department Of Pediatric Surgery,Columbus, OH, USA 2Nationwide Children’s Hospital,Department Of Critical Care Medicine,Columbus, OH, USA 3Ohio State University,College Of Medicine,Columbus, OH, USA 4Nationwide Children’s Hospital,The Research Institute,Columbus, OH, USA 5Ohio State University,Department Of Surgery,Columbus, OH, USA 6Ohio State University,Division Of Pulmonary, Critical Care And Sleep Medicine,Columbus, OH, USA
Introduction:
Burn injury is estimated to be the fourth leading cause of death in children in the United States, according to the World Health Organization, and each year roughly 745,000 children under age 17 require medical attention for burn injuries. These patients are at high risk for adverse outcomes including infectious complications which remain a leading cause of morbidity for burn patients. Both increased (leukocytosis, neutrophilia) and decreased (lymphopenia) white blood cell (WBC) counts have been reported in this setting.
We designed a retrospective study to test the hypothesis that abnormalities in WBC counts that are present beyond the first two days of burn injury will be associated with increased nosocomial infection risk.
Methods:
We used our institution’s trauma registry to identify patients aged 0-18 years old with burns of at least 10% total body surface area (TBSA) from 2005 to 2015. Demographic data, mechanism of injury, and clinical outcomes including infections were collected and verified through chart review. Complete blood counts with differentials were recorded through the first week of hospitalization following injury. Abnormal WBC data were defined as high total WBC count (leukocytosis), high percentage of neutrophils (relative neutrophilia), or low percentage of lymphocytes (relative lymphopenia) according to age-based laboratory norms. Late abnormalities were defined as those noted on post-burn days 3 – 7. Nosocomial infection was defined as a positive culture plus receipt of a full course of antibiotics.
Results:
140 burn patients TBSA≥ 10% were identified during the study period. A higher percentage of patients had late relative lymphopenia (67.2%) than late leukocytosis (10.6%) or late neutrophilia (32.0%). There were no significant differences in age or burn TBSA between subjects with and without late relative lymphopenia. The group of patients with late relative lymphopenia had a significantly higher nosocomial infection rate (71.8%) than those with normal lymphocyte percentages on or after day 3 (42.1%) (p=0.0287). This was not true for patients with late leukocytosis (p=0.34) or late relative neutrophilia (p=1.0).
After controlling for age, gender, mechanism of injury, and TBSA with multivariable logistic regression analysis, the adjusted odds of nosocomial infection were significantly lower in subjects without late relative lymphopenia (AOR = 0.18; 95% CI = 0.04-0.81). Patients with late relative lymphopenia had longer mean hospital and ICU lengths of stay, but the differences were not statistically significant.
Conclusion:
Late relative lymphopenia following severe pediatric thermal injury is associated with the subsequent development of nosocomial infection even when controlling for burn size and other factors. This should be the subject of a future prospective study in a larger sample size.