Transcutaneous Carbon Dioxide Monitoring During Apnea Testing for Determination of Neurologic Death in Children: A Retrospective Case Series.

OBJECTIVES: Determination of neurologic death in children is a clinical diagnosis based on absence of neurologic function with irreversible coma and apnea. Apnea testing during determination of neurologic death assesses spontaneous respiration when PaCO2 increases to greater than or equal to 60 and greater than or equal to 20 mm Hg above pre-apneic baseline. The utility of transcutaneous carbon dioxide measurements during apnea testing in children is unknown. We seek to determine the degree of correlation between paired transcutaneous carbon dioxide and PaCO2 values during apnea testing for determination of neurologic death. DESIGN: Single-center, retrospective case series. SETTING: Twenty-eight bed PICU in a 259-bed, tertiary care, referral center. PATIENTS: Children 0-18 years old undergoing determination of neurologic death between May 2017 and December 2018. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Primary outcomes were paired transcutaneous carbon dioxide and PaCO2 values obtained during determination of neurologic death. Primary analyses included Pearson correlation coefficient, Bland-Altman bias and limits of agreement, and comparative statistics. Descriptive data included demographics, admission diagnoses, hemodynamics, Vasoactive Inotropic Scores, and arterial blood gas measurement. Eight children underwent 15 determination of neurologic death examinations resulting in 31 paired transcutaneous carbon dioxide and PaCO2 values for study. Transcutaneous carbon dioxide and PaCO2 correlated well (r = 0.94; p < 0.01). Bias between transcutaneous carbon dioxide and PaCO2 was -3.29 ± 7.14 mm Hg. Differences in means did not correlate with Vasoactive Inotropic Score (r = 0.2) or patient temperature (r = 0.11). Receiver operator characteristic curve of transcutaneous carbon dioxide after 3-10 minutes of apnea to discriminate positive apnea testing by the standard of PaCO2 yielded an area under the curve of 0.91 and threshold of greater than or equal to 64 mm Hg (sensitivity, 91.7%; specificity, 100%; positive predictive value, 100%; negative predictive value, 92.3%; accuracy, 95.9%). CONCLUSIONS: During apnea testing for determination of neurologic death in children, noninvasive transcutaneous carbon dioxide monitoring demonstrated high correlation, accuracy, and minimal bias when compared with PaCO2. Further validation is required before any recommendation to replace PaCO2 with noninvasive transcutaneous carbon dioxide monitoring can be proposed. However, concurrent transcutaneous carbon dioxide data may limit unnecessary apnea time and associated hemodynamic instability or respiratory decompensation by approximating goal arterial blood sampling to document target PaCO2.

Case Report: Secondary Hemophagocytic Lymphohistiocytosis With Disseminated Infection in Chronic Granulomatous Disease-A Serious Cause of Mortality.

Chronic granulomatous disease (CGD) is a primary immune deficiency due to defects in phagocyte respiratory burst leading to severe and life-threatening infections. Patients with CGD also suffer from disorders of inflammation and immune dysregulation including colitis and granulomatous lung disease, among others. Additionally, patients with CGD may be at increased risk of systemic inflammatory disorders such as hemophagocytic lymphohistiocytosis (HLH). The presentation of HLH often overlaps with symptoms of systemic inflammatory response syndrome (SIRS) or sepsis and therefore can be difficult to identify, especially in patients with a primary immune deficiency in which incidence of infection is increased. Thorough evaluation and empiric treatment for bacterial and fungal infections is necessary as HLH in CGD is almost always secondary to infection. Simultaneous treatment of infection with anti-microbials and inflammation with immunosuppression may be needed to blunt the hyperinflammatory response in secondary HLH. Herein, we present a series of X-linked CGD patients who developed HLH secondary to or with concurrent disseminated CGD-related infection. In two patients, CGD was a known diagnosis prior to development of HLH and in the other two CGD was diagnosed as part of the evaluation for HLH. Concurrent infection and HLH were fatal in three; one case was successfully treated, ultimately receiving hematopoietic stem cell transplantation. The current literature on presentation, diagnosis, and treatment of HLH in CGD is reviewed.