Soo Chul Cho

Chronic Lung Injury in Preterm Lambs: Abnormalities of the Pulmonary Circulation and Lung Fluid Balance

Chronic lung disease of early infancy, or bronchopulmonary dysplasia, is a frequent complication of prolonged mechanical ventilation after premature birth. Pulmonary hypertension and edema are common features of this condition, which is often attributed to long-term, repetitive overinflation of incompletely developed lungs. The overall objective of this work was to examine the effects on the pulmonary circulation and lung fluid balance of different ventilation strategies using large versus small inflation volumes in an animal model of bronchopulmonary dysplasia. We studied 16 newborn lambs that were delivered prematurely (124 ± 3 d gestation, term = 147 d) by cesarean section and mechanically ventilated for 3 to 4 wk. Ten lambs were ventilated at 20 breaths/min, yielding a tidal volume of 15 ± 5 mL/kg, and six lambs were ventilated at 60 breaths/min, yielding a tidal volume of 6 ± 2 mL/kg. All lambs received surfactant at birth and had subsequent surgery for closure of the ductus arteriosus and catheter placement to allow serial measurements of pulmonary vascular resistance and lung lymph flow. Chronic lung injury, documented by serial chest radiographs and postmortem pathologic examination, developed in all lambs irrespective of the pattern of assisted ventilation. Pulmonary vascular resistance, which normally decreases during the month after birth at term, did not change significantly from the first to the last week of study. Lung lymph flow, an index of net transvascular fluid filtration, increased with time in lambs that were ventilated at 20 breaths/min, but not in lambs ventilated at 60 breaths/min. Lymph protein concentration decreased with time, indicative of increased fluid filtration pressure, without evidence of a change in lung vascular protein permeability. Postmortem studies showed interstitial lung edema, increased pulmonary arteriolar smooth muscle and elastin, decreased numbers of small pulmonary arteries and veins, and decreased capillary surface density in distal lung of chronically ventilated lambs compared with control lambs that were killed either 1 d (same postconceptional age) or 3 wk (same postnatal age) after birth at term. Thus, chronic lung injury from prolonged mechanical ventilation after premature birth inhibits the normal postnatal decrease in pulmonary vascular resistance and leads to lung edema from increased fluid filtration pressure. These abnormalities of the pulmonary circulation may contribute to the abnormal respiratory gas exchange that often exists in infants with bronchopulmonary dysplasia.

Epidemiological Profile of Rotavirus Infection in the Republic of Korea: Results from Prospective Surveillance in the Jeongeub District, 1 July 2002 through 30 June 2004

To facilitate future decisions regarding the usefulness of rotavirus vaccines in the Republic of Korea, active surveillance was conducted in a network of clinics, emergency departments, and hospitals serving Jeongeub District, Korea. Children with diarrhea underwent standard clinical evaluations, and stool specimens were collected to test for the presence of rotavirus. Parents were interviewed to collect demographic and family information. From 1 July 2002 through 30 June 2004, a total of 4106 children, representing 1 (50%) of every 2 children <5 years old in the study population, were evaluated for rotavirus diarrhea. Of the 2232 stool specimens obtained throughout the year, 460 (20.6%) were rotavirus positive; however, the monthly prevalence of rotavirus infection peaked at 49.5% in February 2004. Of the 460 rotavirus-positive stool specimens, 366 were obtained from children who visited outpatient clinics, and 94 were obtained from children who were hospitalized. By extrapolating the proportion of rotavirus-positive patients to all children with diarrhea in the surveillance system, we calculate that 882 children in Jeongeub District had rotavirus infection (which would predict that there would be 702 associated clinic visits and 180 hospitalizations). Genotyping of rotavirus strains showed that 39% of strains were type G9P[8], 24% were type G1P[8], 17% were type G3P[8], and 13% were type G2P[4]. The incidence of rotavirus diarrhea peaked at age 13-24 months, and 94% of cases occurred during the first 3 years of life. The annual incidence of all rotavirus disease-associated outcomes was 56.9 cases/1000 children <5 years old (95% confidence interval [CI], 51.9-62.2 cases/1000 children <5 years old). The incidence of rotavirus disease-associated hospitalizations was 11.6 cases/1000 children <5 years old (95% CI, 9.5-14.2 cases/1000 children <5 years old). In Korea, diarrhea is common during childhood, and the incidence of diarrhea due to rotavirus infection suggests that improved programs for the prevention and control of both rotavirus diarrhea and diarrhea due to other causes are needed.

Surfactant treatment at birth reduces lung vascular injury and edema in preterm lambs.

ABSTRACT: To study the effect of surfactant administration on fluid balance in the premature lung, we measured pulmonary vascular pressures, lung lymph and pleural liquid flow, and concentrations of protein in lymph, pleural liquid, and plasma before and after birth in 12 chronically catheterized preterm lambs (127–128 d gestation) treated with either placebo or surfactant just before surgical delivery. Eight lambs received intrapulmonary saline (placebo), and four lambs received surfactant; all lambs were mechanically ventilated with O2 for 8 h after birth. In control lambs, lung lymph and pleural liquid flow increased from 2.7 ± 0.4 mL/h during the 2–4 h before birth to 9.2 ± 2.1 mL/h by 6–8 h after birth; lymph and pleural space protein drainage increased from 58 ± 7 mg/h during the 2–4 h before birth to 134 ± 25 mg/h by 6–8 h after birth. In lambs treated with surfactant, there was no significant increase in lymph and pleural liquid flow after birth (before birth, 2.3 ± 0.3 mL/h; 6ndash;8 h after birth, 3.4 ± 0.9 mL/h); likewise, lymph and pleural space protein drainage did not change after birth (before birth, 54 ± 6 mg/h; 6–8 h after birth, 50 ± 8 mg/h). Postmortem extravascular lung water was significantly less in lambs treated with surfactant compared with control lambs (control, 6.5 ± 0.3 g/g dry lung; surfactant-treated, 5.0 ± 0.2 g/g dry lung). Thus, surfactant administration at birth diminishes transvascular movement of fluid across the pulmonary microcirculation, preserves lung vascular protein permeability, and reduces pulmonary edema in newborn lambs that are delivered prematurely.

Blunted hypoxic pulmonary vasoconstriction in experimental neonatal chronic lung disease.

RATIONALE Neonatal chronic lung disease (CLD), caused by prolonged mechanical ventilation (MV) with O(2)-rich gas, is the most common cause of long-term hospitalization and recurrent respiratory illness in extremely premature infants. Recurrent episodes of hypoxemia and associated ventilator adjustments often lead to worsening CLD. The mechanism that causes these hypoxemic episodes is unknown. Hypoxic pulmonary vasoconstriction (HPV), which is partially controlled by O(2)-sensitive voltage-gated potassium (K(v)) channels, is an important adaptive response to local hypoxia that helps to match perfusion and ventilation in the lung. OBJECTIVES To test the hypothesis that chronic lung injury (CLI) impairs HPV. METHODS We studied preterm lambs that had MV with O(2)-rich gas for 3 weeks and newborn rats that breathed 95%-O(2) for 2 weeks, both of which resulted in airspace enlargement and pulmonary vascular changes consistent with CLD. MEASUREMENTS AND MAIN RESULTS HPV was attenuated in preterm lambs with CLI after 2 weeks of MV and in newborn rats with CLI after 2 weeks of hyperoxia. HPV and constriction to the K(v)1.x-specific inhibitor, correolide, were preferentially blunted in excised distal pulmonary arteries (dPAs) from hyperoxic rats, whose dPAs exhibited decreased K(v)1.5 and K(v)2.1 mRNA and K(+) current. Intrapulmonary gene transfer of K(v)1.5, encoding the ion channel that is thought to trigger HPV, increased O(2)-sensitive K(+) current in cultured smooth muscle cells from rat dPAs, and restored HPV in hyperoxic rats. CONCLUSIONS Reduced expression/activity of O(2)-sensitive K(v) channels in dPAs contributes to blunted HPV observed in neonatal CLD.

The effect of sucrose on infants during a painful procedure.

PURPOSE The purpose of this study was to test the efficacy of treating the pain among newborn infants associated with a medical procedure with sucrose with regard to overall physiological and behavioral stability. METHODS 103 newborn infants were enrolled in this study. The control group (n=63) did not receive any treatment. The experimental group (n=40) received 2 mL of 24% sucrose solution two minutes before a routine heel stick. The pain was assessed by measurements of physiological changes [e.g. pulse rate, oxygen saturation, salivary cortisol (hydrocortisone)] and behavioral changes [e.g. crying time, and the neonatal infant pain scale (NIPS) for neonates]. RESULTS There were no differences among the groups with respect to physiological changes associated with the pain from the procedure. However, there were significant group differences in behavioral changes to the pain. In the control group, the median crying time was 13 seconds, while in the experimental group, the median crying time was 3.5 seconds (P=.000). In the control group the median NIPS score was 4, while in the experimental group the median NIPS score was 2 (P=.000). CONCLUSIONS These findings suggest that sucrose can be an effective method for the management of stress responses in infants with regard to behavior. However, this treatment had no significant physiological effects.

Predictors of growth in children based on 2007 Korean national growth charts

Background:  Postnatal growth patterns in children are associated with various factors within the birth and infancy periods. The aim of the present study was to examine the correlation between growth patterns and parameters including gestational age (GA), birthweight (BW), sex, and feeding method in the records of 61 631 children aged 6–72 months.

CHRONIC LUNG INJURY BLUNTS THE PULMONARY VASOCONSTRICTOR RESPONSE TO HYPOXIA IN PRETERM LAMBS. • 1944

CHRONIC LUNG INJURY BLUNTS THE PULMONARY VASOCONSTRICTOR RESPONSE TO HYPOXIA IN PRETERM LAMBS. • 1944

Satisfaction Levels and Factors Influencing Satisfaction With Use of a Social App for Neonatal and Pediatric Patient Transfer Information Systems: A Questionnaire Study Among Doctors

Background The treatment of neonatal and pediatric patients is limited to certain medical institutions depending on treatment difficulty. Effective patient transfers are necessary in situations where there are limited medical resources. In South Korea, the government has made a considerable effort to establish patient transfer systems using various means, such as websites, telephone, and so forth. However, in reality, the effort has not yet been effective. Objective In this study, we ran a patient transfer information system using a social app for effective patient transfer. We analyzed the results, satisfaction levels, and the factors influencing satisfaction. Methods Naver Band is a social app and mobile community application which in Korea is more popular than Facebook. It facilitates group communication. Using Naver Band, two systems were created: one by the Neonatal Intensive Care Unit and the other by the Department of Pediatrics at Chonbuk National University Childrens Hospital, South Korea. The information necessary for patient transfers was provided to participating obstetricians (n=51) and pediatricians (n=90). We conducted a survey to evaluate the systems and reviewed the results retrospectively. Results The number of patients transferred was reported to increase by 65% (26/40) obstetricians and 40% (23/57) pediatricians. The time taken for transfers was reported to decrease by 72% (29/40) obstetricians and 59% (34/57) pediatricians. Satisfaction was indicated by 83% (33/40) obstetricians and 89% (51/57) pediatricians. Regarding factors influencing satisfaction, the obstetricians reported communication with doctors in charge (P=.03) and time reduction during transfers (P=.02), whereas the pediatricians indicated review of the diagnosis and treatment of transferred patients (P=.01) and the time reduction during transfers (P=.007). Conclusions The users were highly satisfied and different users indicated different factors of satisfaction. This finding implies that users’ requirements should be accommodated in future developments of patient transfer information systems.

Bacteremia Detected by a Peripheral Blood Smear in a Pediatric Surgical Patient with Thrombocytopenia

Microscopic examination of peripheral blood smear (PBS) for detection of microorganisms is simple method that can be used for doctors to confirm the septicemia more swiftly and to select more specific therapy. But it is unusual to find microorganisms in PBS. We report a case of gram negative bacteremia diagnosed by PBS in a severe thrombocytopenic pediatric surgical patient. A 6-month and 2 week old baby with cyanosis was diagnosed congenital heart diseases such as transposition of great arteries, atrial septal defect, and patent ductus arteriosus. The infant underwent surgical operations and the postoperative platelet count progressively decreased in spite of transfusion of multiple platelet concentrates. We performed routine examination of a PBS for evaluation of severe thrombocytopenia. The PBS revealed severe thrombocytopenia, leukopenia with left shifted and some extracellular bacilli. Toxic granulations, toxic vacuoles and some bacilli were observed in the neutrophils. The bacilli were identified as Pseudomonas aeruginosa and Serratia marcescens in blood culture. To our knowledge, this is the second case of bacteremia diagnosed by PBS before the positive blood culture in Korea. We suggest that a PBS is useful for the rapid detection of organisms in cases of septicemia with severe thrombocytopenic pediatric surgical patient. (Korean J Clin Microbiol 2010;13:182-186)