Jin A Sohn

Randomized Crossover Study of Neurally Adjusted Ventilatory Assist in Preterm Infants

OBJECTIVE To determine whether neurally adjusted ventilatory assist (NAVA), a new method of mechanical ventilation that delivers pressure assistance that is proportional to the electrical activity of the diaphragm (EAdi), could lower the inspiratory pressure and respiratory muscle load in preterm infants supported with ventilators. STUDY DESIGN Twenty-six mechanically ventilated preterm infants were randomized to crossover ventilation with NAVA and synchronized intermittent mandatory ventilation (SIMV) with pressure support (PS) for 4 hours each in a randomized order. A 1-hour interval for washout was provided between the 2 modes of ventilation. The ventilator settings were adjusted to maintain similar levels of end-tidal partial pressure of CO(2). The ventilator parameters, vital signs, and gas exchange effects under the 2 ventilatory modes were compared. RESULTS Nineteen infants completed the 9-hour crossover comparison protocol. Peak inspiratory pressure (PIP), work of breathing, and peak EAdi with NAVA were lower than those in SIMV with PS. Calculated tidal volume to peak EAdi ratio and PIP to peak EAdi ratio were higher with NAVA. There were no significant differences in mean airway pressure, inspiratory oxygen fraction, and blood gas values. The measurements of vital signs did not differ significantly between the 2 modes. CONCLUSION NAVA lowered PIP and reduced respiratory muscle load in preterm infants at equivalent inspiratory oxygen fraction and partial pressure of CO(2) of capillary blood in comparison with SIMV with PS.

The Efficacy of Noninvasive Hemoglobin Measurement by Pulse Co-oximetry in Neonates

Objective: To evaluate clinical applicability of noninvasive hemoglobin (Hb) measurement with a pulse CO-oximeter in neonates. Design: Prospective comparison study. Setting: Neonatal ICU. Patients: Fifty-six preterm and term infants with median age = 20 days (range = 1–98 days) and median weight = 1,440g (range = 530–4,230g). Interventions: Hb measurements by Pulse CO-Oximetry (Masimo Radical-7) were recorded immediately prior to venous samplings. Measurements and Main Results: The collected data were compared with the corresponding venous Hb level obtained in laboratory testing, and a total of 137 data pairs were analyzed. Noninvasive Hb values measured with a pulse CO-oximeter were significantly correlated with the venous Hb levels (correlation coefficient, r = 0.758; p < 0.001). Hb values measured with a pulse CO-oximeter were higher than those measured with a laboratory hematology analyzer (13.3±2.6g/dL vs. 12.5±3.1g/dL). In terms of the agreement between the laboratory analyzer and the pulse CO-oximeter, 94.8% of the measurements fell within two standard deviations of the mean difference. Conclusion: Noninvasive Hb measurements with Pulse CO-Oximetry provide clinically acceptable accuracy, and they were significantly correlated with laboratory Hb measurement in neonates. In terms of the clinical applicability, noninvasive Hb monitoring with a pulse CO-oximeter could be useful in the early detection of Hb changes in neonates.

Population pharmacokinetics of theophylline in premature Korean infants.

Objectives: The aim of this study was to investigate the population pharmacokinetics of theophylline in premature Korean infants and to assess the influence of clinical covariates. Methods: Blood samples were first obtained after 1 week of maintenance dosing and then acquired approximately 4 weeks after continuous dosing. The time points were just before dosing and 2, 4, or 6 hours (at randomly assigned time points) after dosing. Two single-nucleotide polymorphism markers, −3860 G>A (CYP1A2*1C) and −163C>A (CYP1A2*1F), were genotyped. Gestational age (GA), postnatal age (PNA), postconceptional age (PCA = GA + PNA), body weight (BW), height, serum AST, serum ALT, serum BUN, serum creatinine, oxygen support, sex, delivery mode, and CYP1A2 genotypes were used for covariate model building. External validation was analyzed using data from an additional 27 patients. Results: A total of 334 serum concentration measurements were made in 100 patients. A one-compartment absorptive model with first-order elimination was fitted to the data in NONMEM (version 7.1.2). The final model included the following parameters: Clearance (L/h) = 0.00492 × (BW)3.53 + 0.00646 × (PNA), and volume of distribution (L) = 1.53 × (BW). The addition of the CYP1A2*1C or CYP1A2*1F genotypes to the model did not improve the model. The external validation results confirmed the predictive performance without bias in the final model. Conclusions: The selected covariates were generally consistent with previous studies. However, the mean volume of distribution was higher than the values reported in other population pharmacokinetic studies, which may have been due to the use of 2 sampling time points. The predictive performance was reasonably acceptable. Therefore, the present model may permit more accurate selection of doses to achieve target theophylline concentrations in premature infants.

A case of mucolipidosis II presenting with prenatal skeletal dysplasia and severe secondary hyperparathyroidism at birth

Mucolipidosis II (ML II) or inclusion cell disease (I-cell disease) is a rarely occurring autosomal recessive lysosomal enzyme-targeting disease. This disease is usually found to occur in individuals aged between 6 and 12 months, with a clinical phenotype resembling that of Hurler syndrome and radiological findings resembling those of dysostosis multiplex. However, we encountered a rare case of an infant with ML II who presented with prenatal skeletal dysplasia and typical clinical features of severe secondary hyperparathyroidism at birth. A female infant was born at 37+1 weeks of gestation with a birth weight of 1,690 g (<3rd percentile). Prenatal ultrasonographic findings revealed intrauterine growth retardation and skeletal dysplasia. At birth, the patient had characteristic features of ML II, and skeletal radiographs revealed dysostosis multiplex, similar to rickets. In addition, the patient had high levels of alkaline phosphatase and parathyroid hormone, consistent with severe secondary neonatal hyperparathyroidism. The activities of β-D-hexosaminidase and α-N-acetylglucosaminidase were moderately decreased in the leukocytes but were 5- to 10-fold higher in the plasma. Examination of a placental biopsy specimen showed foamy vacuolar changes in trophoblasts and syncytiotrophoblasts. The diagnosis of ML II was confirmed via GNPTAB genetic testing, which revealed compound heterozygosity of c.3091C>T (p.Arg1031X) and c.3456_3459dupCAAC (p.Ile1154GlnfsX3), the latter being a novel mutation. The infant was treated with vitamin D supplements but expired because of asphyxia at the age of 2 months.

Developmental change of amplitude-integrated electroencephalographic activity in preterm infants with intraventricular hemorrhage

BACKGROUND Amplitude-integrated electroencephalography (aEEG) allows continuous brain function monitoring at bedside. OBJECTIVES This prospective cohort study was designed to longitudinally evaluate aEEG tracings at increased postmenstrual age (PMA) in preterm infants with intraventricular hemorrhage (IVH). METHODS Biweekly aEEG recordings were performed on preterm infants <32 weeks gestational age from 24 to 36 weeks PMA. The tracings were evaluated according to a scoring system adapted from Burdjalov et al. RESULTS We analyzed 496 aEEG recordings in 105 preterm infants. The control group consisted of 42 infants with no IVH, whereas the IVH grade I, II, III, and IV groups consisted of 38, 8, 3, and 14 infants, respectively. There were significant differences in the cycling and total maturation scores among the IVH groups at 36 weeks PMA (p = 0.010 and p = 0.006, respectively). The IVH-IV patients maintained low scores in their cycling as their PMA increased, in contrast to their continuity and amplitude scores. The risk factors affecting the aEEG maturation scores at 36 weeks PMA in the IVH-IV patients included seizure events with the administration of antiepileptic drugs and the insertion of external ventricular drains (β = -0.679 and β = -0.418, respectively; p = 0.003). CONCLUSIONS The low cycling scores persisted until 36 weeks PMA in the IVH-IV group.

Misdiagnosis of fetus-in-fetu as meconium peritonitis

Fetus-in-fetu (FIF) is a rare congenital condition in which a fetiform mass is detected in the host abdomen and also in other sites such as the intracranium, thorax, head, and neck. This condition has been rarely reported in the literature. Herein, we report the case of a fetus presenting with abdominal cystic mass and ascites and prenatally diagnosed as meconium pseudocyst. Explorative laparotomy revealed an irregular fetiform mass in the retroperitoneum within a fluid-filled cyst. The mass contained intestinal tract, liver, pancreas, and finger. Fetal abdominal cystic mass has been identified in a broad spectrum of diseases. However, as in our case, FIF is often overlooked during differential diagnosis. FIF should also be differentiated from other conditions associated with fetal abdominal masses.

The efficacy and safety of Montelukast sodium in the prevention of bronchopulmonary dysplasia

Purpose The purpose of this study was to evaluate the efficacy and safety of Montelukast sodium in the prevention of bronchopulmonarydysplasia (BPD). Methods The Interventional study was designed as a multicenter, prospective, and randomized trial, with open labeled and parallel-experimental groups, 66 infants were enrolled and allocated to either the case group (n=30) or the control group (n=36) based on gestational age (GA). Infants in the case group were given Montelukast sodium (Singulair) based on their body weight (BW). Zero week was defined as the start time of the study. Results The incidence of moderate to severe BPD was not different between the groups (case group: 13 of 30 [43.3%] vs. control group: 19 of 36 [52.8%], P=0.912). Additionally, secondary outcomes such as ventilation index, mean airway pressure and resort to systemic steroids were not significantly different. There were no serious adverse drug reactions in either group, and furthermore the rate of occurrence of mild drug related-events were not significantly different (case group: 10 of 42 [23.8%] vs. control group: 6 of 48 (15.8%), P=0.414). Conclusion Montelukast was not effective in reducing moderate or severe BPD. There were no significant adverse drug events associated with Montelukast treatment.

Neuroimaging in Preterm Infants: Comparison between Magnetic Resonance Imaging and Ultrasonography

목적: 미숙아에서 뇌 자기공명영상(magnetic resonance imaging,MRI) 검사는 신경발달의 결과를 예측하는 방법으로서 점차 많이사용되고 있지만, 정기적 뇌 초음파 검사는 여전히 신생아 뇌 검사방법의 기준으로 남아있다. 미숙아에서 퇴원 무렵에 시행된 뇌 자기공명영상과 입원기간 중 연속적으로 시행된 뇌 초음파영상을...