Biomedical subjects

Ke-Chang Chang

Publications and source records attributed to Ke-Chang Chang.

7 recordsLinked to original sources

PubMed2005

Effect of laser-assisted uvulopalatoplasty on oral airway resistance during wakefulness in obstructive sleep apnea syndrome.

The aim of the study was to evaluate the effects of successful laser-assisted uvulopalatoplasty (LAUP) on oral airway resistance (R(OA)) during wakefulness in patients with OSAS. Fifteen healthy subjects (group I) and 25 subjects (group II) with moderately severe or severe obstructive sleep apnea syndrome (OSAS) proven by an overnight sleep study and who desired LAUP were enrolled. All underwent an overnight sleep study, pulmonary function testing and measurement of oral airway resistance [R(OA) (including impedance (Zrs), resistance (R) and reactance (X)] measurement by Impulse Oscillometry (IOS) (MasterScreen IOS, VIASYS Healthcare GmbH, Germany) in the upright (seated) position and then in the supine position while awake. Group II subjects had these measurements twice, both before and 3 months after LAUP. Based on the assessment of their sleep study after LAUP, they were divided into two groups: responders (group IIa) and nonresponders (group IIb). Zrs was normal in the sitting position both before and after LAUP in both groups IIa and IIb and comparable to that of group I controls. There was an increase in Zrs in the supine position in both groups IIa and IIb subjects before LAUP. After LAUP, the Zrs in group IIb subjects remained elevated, while that in group IIa subjects returned to levels comparable to those in the normal controls. OSAS patients before LAUP have abnormal R(OA) in the supine position as reflected by a high Zrs. The Zrs is improved after LAUP that successfully ameliorates OSAS.

Adult↗

PubMed2005

Effect of treatment by laser-assisted uvulopalatoplasty on cardiopulmonary exercise test in obstructive sleep apnea syndrome.

OBJECTIVES: To evaluate the effects of successful laser-assisted uvulopalatoplasty (LAUP) on cardiopulmonary exercise testing (CPET) in patients with obstructive sleep apnea syndrome (OSAS). STUDY DESIGN AND SETTING: Twenty-five subjects with moderately severe or severe OSAS who desired LAUP were enrolled. All patients had an overnight sleep study and CPET before and 3 months after LAUP. Patients were divided into 2 groups based on the success (group I) or failure (group II) of LAUP to improve their sleep apnea. RESULTS: Successful LAUP in group I was followed by improvement in right ventricular ejection fraction, maximal work rate (WRmax), VO2max/kg, anaerobic threshold, oxygen pulse, and a lower breathing reserve. CPET results were unchanged after LAUP in group II subjects. CONCLUSION: Patients with OSAS before LAUP had abnormal CPET as reflected by low VO2peak/kg, WRmax, anaerobic threshold, and oxygen pulse. All of these variables improved after LAUP that successfully ameliorated OSAS.

Adult↗

PubMed2002

Laryngeal neurofibroma: case report of a child.

Neurofibromatosis is characterized by multiple café-au-lait spots and cutaneous neurofibromas. Laryngeal involvement in neurofibromatosis is rare and is usually manifested by obstructive airway symptoms. We encountered a 1 year 8-month-old girl who was a victim of neurofibromatosis with the presentation of stridor. Fiberoptic laryngoscopy revealed a round smooth mass over the right aryepiglottic fold which prolapsed into the larynx during inspiration. Carbon dioxide laser excision was performed and histopathologic examination revealed a plexiform neurofibroma. The patient had regular follow up for almost 4 years. Even though there seemed to be a recurrence, she remained symptom free.

Biopsy, Needle↗

PubMed2002

A universal newborn hearing screening program in Taiwan.

OBJECTIVE: Mackay Memorial Hospital and the Children's Hearing Foundation established a pilot universal newborn hearing screening program in November 1998. Our objective was to assess the feasibility, accuracy and cost effectiveness of implementing universal newborn hearing screening in Taiwan. METHOD: Between November 1998 and October 2000 a total of 6765 newborns were screened for hearing loss prior to discharge from the wellborn nursery at Mackay Memorial Hospital. The average age of the subjects at the initial screening test was 52 h. The program employed a three stage hearing screening protocol using transient evoked otoacoustic emmisions (TEOAE) screening with referral for diagnostic auditory brainstem response assessment. RESULTS: The mean TEOAE screening time per ear was 41.43 s. The overall pass rate at the time of hospital discharge was 93.6%. Thus achieving an acceptable referral rate of 6.4% for diagnostic audiological assessments. Nine newborns were identified with permanent bilateral hearing impairment. 26 newborns were identified with permanent unilateral hearing impairment. Infants identified with bilateral hearing loss were immediately referred to the Children's Hearing Foundation for hearing aid assessment and fitting. Infants as young as 5 weeks of age were successfully fitted with hearing instruments and enrolled in the family centered early intervention program at the Children's Hearing Foundation. CONCLUSION: The frequency of bilateral congenital hearing loss requiring amplification in this population is shown to be approximately 1 in 752 newborns. This finding is consistent with previous research, which has indicated hearing loss to be the most frequently occurring birth defect. Universal newborn hearing screening using TEOAEs proved to be a cost effective and feasible method of identifying congenital hearing loss in Taiwan. The existence of many successful screening programs worldwide and the availability of fast, objective, reliable and inexpensive hearing screening procedures means that universal newborn hearing screening is becoming the standard of care.

Acoustic Stimulation↗

PubMed2002

Effects of treatment by laser-assisted uvuloplasty on sleep energy expenditure in obstructive sleep apnea patients.

The purpose of this study was to evaluate the effect of successful laser-assisted uvulopalatoplasty (LAUP) on sleep energy expenditure (EE) in obstructive sleep apnea syndrome (OSAS) patients. Fifteen healthy subjects (group I) and 25 patients with moderately severe or severe OSAS (group II) proven by overnight sleep study and who wanted LAUP were enrolled. During the night of the sleep studies, EE was measured with a metabolic cart (indirect calorimetry with canopy), including basal metabolic rate (BMR), mean sleep EE, lowest sleep EE, ratios of mean sleep EE/BMR, and lowest sleep EE/BMR. For the OSAS patients, a second sleep study with EE measurement was performed 3 months after LAUP. Based on this assessment of their sleep architecture, they were divided into 2 groups: responders (group IIa) and nonresponders (group IIb). The mean sleep EE, the ratio of mean sleep EE/BMR and lowest EE/BMR were significantly higher in group II than group I. After LAUP in group II, 6 patients were found to be responders (group IIa) and 19 patients were nonresponders (group IIb). Group IIa had decreased mean sleep EE, ratios of mean sleep EE/BMR, and lowest sleeping EE/BMR after LAUP than before LAUP compared with no significant changes in group IIb after LAUP. In conclusion, there is increased sleep EE in moderately severe OSAS patients when compared with normal controls. LAUP, when effective in reversing the sleep abnormalities, also normalizes the sleep EE. If it does not adequately treat the OSAS, however, the sleep EE remains abnormal.

Adult↗

PubMed2002

Congenital pyriform aperture stenosis: surgery and evaluation with three-dimensional computed tomography.

OBJECTIVE: We described the surgical efficacy of congenital pyriform aperture stenosis by measuring the width of the nasal pyriform aperture with three-dimensional computed tomography. METHODS: Six patients with congenital pyriform aperture stenosis accepted surgical intervention. Three-dimensional computed tomography was performed for preoperative and postoperative evaluation of nasal pyriform aperture width. We marked the midpoint between the tip of nasal bone and the anterior nasal spine. The distances between the bilateral nasal processes of the maxilla and between the lateral rims of the pyriform aperture were measured by crossing the midpoint horizontally. RESULTS: Among the six patients (three male and three female patients), the mean age was 76.2+/-23.9 days. Silicon stents were removed 6 to 7 days after operation. During 9 months of follow-up, there were no cases of restenosis, respiratory failure, or cyanosis. The mean preoperative and postoperative interprocess distances were 4.5+/-0.84 and 8.7+/-1.37 mm, respectively, and data were statistically significant at a confidence level of P <.05. The mean preoperative and postoperative interwall distances were 9.8+/-0.75 and 10.8+/-1.5 mm, respectively. CONCLUSIONS: Congenital pyriform aperture stenosis should be suspected whenever there is both severe nasal obstruction and difficulty in passing a small catheter or nasogastric tube through the anterior nasal valve. Operation is the most extreme treatment, but it is effective for congenital pyriform aperture stenosis. Nasal stenting for 7 days seemed to be adequate. The use of three-dimensional computed tomography to evaluate preoperative and postoperative nasal pyriform aperture is effective and reliable.

Diagnosis, Differential↗

PubMed2002

Hypoglossal schwannoma in the submandibular space.

Most schwannomas of the hypoglossal nerve originate from the intracranial portion, but they may extend extracranially. Solitary and extracranial schwannomas are extremely rare. We report a case of submandibular hypoglossal schwannoma along with its clinical course and management.

Adult↗