Seong Jong Park

Toxic Inhalational Injury-Associated Interstitial Lung Disease in Children

Interstitial lung disease in children (chILD) is a group of disorders characterized by lung inflammation and interstitial fibrosis. In the past recent years, we noted an outbreak of child in Korea, which is possibly associated with inhalation toxicity. Here, we report a series of cases involving toxic inhalational injury-associated chILD with bronchiolitis obliterans pattern in Korean children. This study included 16 pediatric patients confirmed by lung biopsy and chest computed tomography, between February 2006 and May 2011 at Asan Medical Center Childrens Hospital. The most common presenting symptoms were cough and dyspnea. The median age at presentation was 26 months (range: 12-47 months), with high mortality (44%). Histopathological analysis showed bronchiolar destruction and centrilobular distribution of alveolar destruction by inflammatory and fibroproliferative process with subpleural sparing. Chest computed tomography showed ground-glass opacities and consolidation in the early phase and diffuse centrilobular nodular opacity in the late phase. Air leak with severe respiratory difficulty was associated with poor prognosis. Although respiratory chemicals such as humidifier disinfectants were strongly considered as a cause of this disease, further studies are needed to understand the etiology and pathophysiology of the disease to improve the prognosis and allow early diagnosis and treatment.

The Efficacy of the COMFORT Scale in Assessing Optimal Sedation in Critically Ill Children Requiring Mechanical Ventilation

Sedation is often necessary to optimize care for critically ill children requiring mechanical ventilation. If too light or too deep, however, sedation can cause significant adverse reactions, making it important to assess the degree of sedation and maintain its optimal level. We evaluated the efficacy of the COMFORT scale in assessing optimal sedation in critically ill children requiring mechanical ventilation. We compared 12 month data in 21 patients (intervention group), for whom we used the pediatric intensive care unit (PICU) sedation protocol of Asan Medical Center (Seoul, Korea) and the COMFORT scale to maintain optimal sedation, with the data in 20 patients (control group) assessed before using the sedation protocol and the COMPORT scale. Compared with the control group, the intervention group showed significant decreases in the total usage of sedatives and analgesics, the duration of mechanical ventilation (11.0 days vs. 12.5 days) and PICU stay (15.0 days vs. 19.5 days), and the development of withdrawal symptoms (1 case vs. 7 cases). The total duration of sedation (8.0 days vs. 11.5 days) also tended to decrease. These findings suggest that application of protocol-based sedation with the COMPORT scale may benefit children requiring mechanical ventilation.

Infections after living donor liver transplantation in children.

The aim of this study was to evaluate the infectious complications after living donor liver transplantation (LDLT) in children. We enrolled 95 children (38 boys and 57 girls) who underwent LDLT from 1994 to 2004. The median age was 22 months (range, 6 months to 15 yr). We retrospectively investigated the proven episodes of bacterial, viral, and fungal infection. There occurred 150 infections in 67 (70%) of 95 patients (1.49 infections/patient); 74 in 43 patients were bacterial, 2 in 2 were fungal, and 74 in 42 were viral. The most common sites of bacterial infection were the bloodstream (33%) and abdomen (25%). Most of the bacterial infections occurred within the first month after LDLT. Bacterial and fungal infections did not result in any deaths. The most common causes of viral infection were Epstein-Barr virus in 37 patients and cytomegalovirus in 18. Seven of the 14 deaths after LDLT were associated with viral infection. Our study suggests that infection is one of the important causes of morbidity and mortality after LDLT. Especially careful monitoring and management of viral infections is crucial for improving the outcome of LDLT in children.

Placement of covered retrievable expandable metallic stents for pediatric tracheobronchial obstruction.

PURPOSE To evaluate the safety and clinical effectiveness of placement of covered retrievable expandable metallic stents in seven children with tracheobronchial obstruction. MATERIALS AND METHODS Using bronchoscopic and fluoroscopic guidance, stent placement was performed in seven children (median age, 12 y; range, 2 mo-14 y). The stents were electively removed 6 months after placement or whenever there were symptom-producing complications. During the follow-up period, technical and clinical success, complications and related reinterventions, and long-term prognosis were retrospectively evaluated. RESULTS Stent placement was technically successful for a total of eight stents in all seven patients. Stent removal was also successful for six stents in five patients; two stents were removed electively 6 months after placement, and four stents were removed due to symptom-producing complications. Clinical success defined as ventilator weaning, extubation, or dyspnea improvement was achieved in all patients 1 week after stent placement. A possible infection source in one stent and abundant granulation tissue caused by three stents necessitated removal of four stents in three patients. During the mean follow-up period of 18.7 months (range, 1-31 mo) after stent placement, three patients died due to the progression of underlying cardiopulmonary disease or malignancy. There were no deaths directly related to stent placement or related complications. CONCLUSION Although the findings were based on a small series, placement of covered retrievable expandable metallic stents seems to be safe and effective for the treatment of pediatric tracheobronchial obstruction. Ventilator weaning, extubation, or dyspnea improvement was possible in all patients after stent placement.

Extracorporeal membrane oxygenation support in a patient with status asthmaticus.

Status asthmaticus is a rare, fatal condition, especially in children. Sometimes respiratory support is insufficient with a mechanical ventilator or medical therapy for patients with status asthmaticus. In such situations, early extracorporeal membrane oxygenation application is a useful method for treating refractory respiratory failure. We report on a case of a six-year-old, male child who underwent venovenous extracorporeal membrane oxygenation support for refractory status asthmaticus.

Early changes in SOFA score as a prognostic factor in pediatric oncology patients requiring mechanical ventilatory support.

Purpose To evaluate whether changes in outcome prediction scores during the first 72 hours after admission to a pediatric intensive care unit (PICU) are more predictive of outcome than single assessments at admission in pediatric oncology patients requiring mechanical ventilatory support for more than 3 days. Patients and Methods The medical records of 54 consecutive pediatric oncology patients requiring mechanical ventilation over 72 hours in the PICU of the Asan Medical Center, Seoul, Korea, between January 2006 and December 2008, were retrospectively reviewed. Results Although both initial Sequential Organ Failure Assessment (SOFA) score and change in SOFA score (Δ-SOFA) correlated well with mortality, Δ-SOFA score showed a significantly stronger correlation (P<0.001) and a larger area under the receiver operating characteristic curve than did initial SOFA score. Patients with positive and negative Δ-SOFA scores showed statistically significant differences in mortality (18.5% vs. 88.2%, P<0.001). In addition, early changes in respiratory parameters, such as PaO2/FiO2 (P/F) ratio, oxygenation index (OI), and ventilation index (VI), evaluated serially during the first 3 days, also correlated with mortality. Patients showing improvement in these respiratory parameters displayed significantly lower mortality than did patients with worsening of these parameters (P<0.01). Conclusions Serial evaluation of SOFA score during the first few days after PICU admission was a good predictor of prognosis in pediatric oncology patients mechanically ventilated over 3 days. Independent of initial SOFA score, Δ-SOFA score during the first 72 hours closely correlated with outcome. Early changes in respiratory parameters, such as P/F ratio, OI, and VI, may also provide valuable prognostic information in such patients.

Long-term Growth of Pediatric Patients Following Living-Donor Liver Transplantation

In order to determine the influence of living donor liver transplantation (LDLT) on long-term growth, we studied the progress of 36 children who had survived more than 5 yr after LDLT from 1994 to 1999. The median age at the transplantation was 1.5 yr (range: 6 months-15 yr) and the median follow-up period was 6.5 yr (range: 5-9 yr). A height standard deviation score (zH) was analyzed for each patient according to medical records. Significant catch-up growth occurred within 2 yr after LDLT with a mean zH changing from -1.2 to 0.0 and was maintained for up to 7 yr post-transplantation (zH-0.1). Younger children (<2 yr) were more growth-retarded at the time of LDLT, but showed higher catch-up growth rates and their final zH was greater than that of older children. Children with liver cirrhosis were more growth-retarded at the time of LDLT, but showed significant catch-up growth and their final height was similar to children with fulminant hepatitis. Growth in children who experienced significant hepatic dysfunction after LDLT was not significantly different from those without graft dysfunction. There was no difference between the types of immunosuppressants used. Our finding suggests that LDLT can result in adequate catch-up linear growth, and this effect can persist even after 7 yr post-transplantation.

Successful liver transplantation following veno-arterial extracorporeal membrane oxygenation in a child with fulminant Wilson disease and severe pulmonary hemorrhage: a case report.

Son SK, Oh SH, Kim KM, Lee YJ, Jhang WK, Park SJ, Shin HJ, Park J‐J, Kim TH, Kim DY, Hwang S, Park K‐M, Lee Y‐J, Lee S‐G. Successful liver transplantation following veno‐arterial extracorporeal membrane oxygenation in a child with fulminant Wilson disease and severe pulmonary hemorrhage: A case report. 
Pediatr Transplantation 2011.

The Effect of Rush Immunotherapy with House Dust Mite in the Production of IL-5 and IFN-γ from the Peripheral Blood T Cells of Asthmatic Children

Although the mechanisms are unclear, rush immunotherapy (RIT) may be effective to treat allergic diseases. We investigated the long-term modifications of cellular immunity as a mechanism of RIT. The RIT group, included 15 house dust mite (HDM)-sensitized asthmatic children, received RIT only with Dermatophagoides farinae (Der f) and Dermatophagoides pteronyssinus (Der p), whereas the control group, consisted of 10 HDM-sensitized asthmatic children, did not receive RIT. The asthma symptom scores and the skin reactivities to Der f were measured. The cellular proliferative responses and intracellular interleukin (IL)-5 and interferon (IFN)-γ productions from peripheral blood T cells were also measured before, 8 weeks and 1 yr after RIT. The symptom scores, skin reactivity to Der f and cellular proliferative responses to Der f were decreased significantly after 8 weeks and maintained until 1 yr of RIT. The IFN-γ/IL-5 ratio of the CD3(+) and CD4(+) cells were increased significantly after 8 weeks and maintained until 1 yr of RIT, while there were no changes in the control group. These data indicate that the continuous functional modification from Th2 to Th1 phenotype of the CD4(+) T cells are developed after RIT in the asthmatic children sensitized with HDM.

High prevalence of neonatal presentation in Korean patients with citrullinemia type 1, and their shared mutations.

Type 1 citrullinemia (CTLN1) often presents as a hyperammonemic encephalopathy in the neonatal period, but it can also develop in the late-infantile period and in adults. In addition, some patients can be identified in the presymptomatic period by neonatal or family member screening. In this study, twenty Korean patients with CTLN1 (19 families) were examined; fourteen patients with neonatal-onset, three with late-onset, and three that were identified presymptomatically. The 13 patients with hyperammonemic encephalopathy received continuous venovenous hemofiltration (CVVH) or peritoneal dialysis (PD). Although the hyperammonemia was relieved more effectively in the six patients on CVVH than the seven on PD, most of these patients suffered from severe neurologic deficits. Recurrent hyperammonemic episodes (7 pts, 35%), recurrent and reversible acute hepatic dysfunction (5 pts, 25%), and focal cerebral infarction (2 pts, 10%) were noted. The neonates with hyperammonemic encephalopathy had extensive brain injuries at the onset of hyperammonemia, followed by encephalomalacia and brain atrophy at quite an early age. Genetic testing for the ASS1 gene revealed a different mutation spectrum from those of other ethnicities; Three common mutations, c.421-2A>G (37.8%), c.1128-6_1188dup67 (18.9%), and p.Gly324Ser (16.2%), accounted for 73% of the mutations. The poor outcome was expected in patients with the peak ammonia level at onset over 600μmol/L, whose proportion was higher in the neonatal presentation group than in the presymptomatic/late presentation group. Our findings add to the current understanding of the ethnic diversity of CTLN1 from both clinical and genetic perspectives.