Browsing by Author "Chen, I-Chen"

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Combined Noninvasive Ventilation and Mechanical In-Exsufflator in the Treatment of Pediatric Acute Neuromuscular Respiratory Failure
(2014-06-01)
Chen, Tai-Heng
;
Hsu, Jong-Hau
;
Wu, Jiunn-Ren
;
Dai, Zen-Kong
;
Chen, I-Chen
ObjectivesThe present study aims to evaluate the efficacy and complications of combined noninvasive ventilation (NIV) and assisted coughing by mechanical in-exsufflator (MIE) for acute respiratory failure (ARF) in children with neuromuscular disease (NMD). MethodsA prospective study was conducted in the pediatric intensive care unit. Children with NMD and ARF treated by combined NIV and MIE were included. Treatment success was defined as freedom from tracheal intubation during the hospital stay. Physiologic indices including PaO2, PaCO2, pH, and PaO2/FiO(2) were recorded before and 12, 24hr after the use of NIV/MIE. ResultsCombined NIV/MIE was used in 15 NMD children (mean: 8.1 years, range: 3 months to 18 years) with 16 cases of ARF. There was no mortality in this cohort. Treatment success was achieved in 12 cases (75%), including six cases (38%) demanding Do Not Intubate. ARF was due to pneumonia, with a mean baseline PaCO2 of 73.219.0mmHg. In the success group, hypercarbia and acidosis improved after use of NIV/MIE for 24hr (PaCO2: 71.7 +/- 18.6mmHg vs. 55.8 +/- 11.6mmHg, P<0.01; pH: 7.29 +/- 0.07 vs. 7.38 +/- 0.05, P<0.01). All patients tolerated NIV/MIE well despite transient skin pressure sores in five cases. ConclusionsCombined NIV/MIE is a safe and effective approach to rapidly improve physiologic indices and decrease the need for intubation in NMD children with ARF. NIV/MIE provides a good alternative for those refusing intubation. Pediatr Pulmonol. 2014; 49:589-596. (c) 2013 Wiley Periodicals, Inc.
Combined noninvasive ventilation and mechanical insufflator-exsufflator for acute respiratory failure in patients with neuromuscular disease: effectiveness and outcome predictors
(2019-09-01)
Chen, Tai-Heng
;
Liang, Wen-Chen
;
Chen, I-Chen
;
Liu, Yi-Ching
;
Hsu, Jong-Hau
Background: To determine the effectiveness of combined noninvasive ventilation (NIV) and mechanical insufflator-exsufflator (MI-E) for acute respiratory failure (ARF) in patients with neuromuscular disease (NMD), and outcome predictors. Methods: A prospectively observational study of patients with ARF was conducted in a pediatric intensive care unit (PICU). All received combined NIV/MI-E during PICU stays between 2007 and 2017. Pertinent clinical variables of heart rate (HR), respiratory rate (RR), pH, PaCO2, and PaO2/FiO(2) ratio were collected at baseline and at 2 h, 4-8 h, and 12-24 h after initiating use of NIV/MI-E. Treatment success was defined as avoiding intubation. Results: A total of 62 ARF episodes in 56 patients with NMD (median age, 13 years) were enrolled. The most frequent underlying NMD was spinal muscular atrophy (32/62, 52%). ARF was primarily due to pneumonia (65%). The treatment success rate was 86%. PICU stay and hospitalization were shorter in the success group (9.4 +/- 6.1 vs. 21.9 +/- 13.9 days and 16.3 +/- 7.8 vs. 33.6 +/- 17.9 days, respectively; both p < 0.05). HR, RR, pH, and PaCO2 showed a progressive improvement, particularly after 4 h following successful NIV/MI-E treatment. RR decrease at 4 h, and pH increase and PaCO2 decrease at 4-8 h might predict success of NIV/MI-E treatment. The multivariate analysis identified PaCO2 at 4-8 h of 58.0 mmHg as an outcome predictor of NIV/MI-E treatment. Conclusions: Applying combined NIV/MI-E in the acute care setting is an efficient means of averting intubation in NMD patients with ARF. Clinical features within 8 h of the institution may predict treatment outcome. The reviews of this paper are available via the supplemental material section.
Highly Reflective Ag/La Bilayer Ohmic Contacts to p-Type GaN
(2011)
Chen, I-Chen
;
Chen, Yi-Dar
;
Hsieh, Chih-Chien
;
Kuo, Cheng-Huang
;
Chang, Li-Chuan
A new Ag/La bilayer metal contact scheme has been developed for producing high reflectance and low contact resistivity ohmic contacts to p-GaN. An excellent reflectance of over 91% at 460 nm wavelength and low specific contact resistivity of 1.6 x 10(-4) Omega cm(2) were obtained from Ag/La (150/20 nm) contact annealed at 450 degrees C for 1 min. The La overlayer was oxidized to form La(2)O(3) when exposed to air, which effectively suppresses exposure of the Ag layer to oxygen atmosphere during annealing, leading to a good ohmic contact with smooth surface morphology and high reflectance. Additionally, Ag/La contacts show excellent thermal stability after a long thermal annealing at 300 degrees C in air ambient. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3533673] All rights reserved.
Improved light reflectance and thermal stability of Ag-based ohmic contacts on p-type GaN with La additive
(2013-05-01)
Chen, I-Chen
;
Cheng, Bo-Yuan
;
Ke, Wen-Cheng
;
Kuo, Cheng-Huang
;
Chang, Li-Chuan
We investigated the effect of La additive on the improvement of light reflectance and thermal stability of Ag contacts on p-GaN. A high reflectance of over 90% at 460 nm wavelength and low specific contact resistivity of 5.5 x 10(-5) Omega cm(2) were obtained from La-containing Ag contacts annealed at 300 degrees C for 1 min, which also show better thermal stability than Ag contacts after annealing in air ambient. The experimental results reveal that the addition of La could effectively slow down Ag migration in < 1 1 1 > direction during annealing, and thus suppress the Ag agglomeration at elevated temperature, leading to a good ohmic contact with improved high reflectance and thermal stability. (C) 2013 Elsevier Ltd. All rights reserved.
Influence of Mg-containing precursor flow rate on the structural, electrical and mechanical properties of Mg-doped GaN thin films
(2012-10-15)
Ke, Wen-Cheng
;
Jian, Sheng-Rui
;
Chen, I-Chen
;
Jang, Jason S. -C.
;
Chen, Wei-Kuo
The effects of Mg-containing precursor flow rate on the characteristics of the Mg-doped GaN (GaN:Mg) were systematically studied in this study. The GaN:Mg films were deposited on sapphire substrates by metal-organic chemical-vapor deposition (MOCVD) with various flow rates of 25, 50, 75 and 100 sccm of bis-(cyclopentadienyl)-magnesium (Cp2Mg) precursor. The structural, electrical and nanomechanical properties of GaN:Mg thin films were characterized by X-ray diffraction (XRD), atomic force microscopy (AFM). Hall measurement and nanoindentation techniques, respectively. Results indicated that GaN:Mg films obtained with 25 sccm Cp2Mg possess the highest hole concentration of 3.1 x 10(17) cm(-3). Moreover, the hardness and Young's modulus of GaN:Mg films measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) option showed positive dependence with increasing flow rate of Cp2Mg precursor, presumably due to the solution hardening effect of Mg-doping. (C) 2012 Elsevier B.V. All rights reserved.