Noise and Room Acoustic Conditions in a Tertiary Referral Hospital, Seoul National University Hospital

BACKGROUND AND OBJECTIVES: Noise levels and room acoustic parameters at a tertiary referral hospital, Seoul National University Hospital (SNUH) in Korea, are investigated. MATERIALS AND METHODS: Through a questionnaire, acoustically problematic rooms are identified. Noise levels in emergency rooms (ERs) and intensive care units (ICUs) are measured over about three days. Acoustically critical and problematic rooms in the otolaryngology department are measured including examination rooms, operating rooms, nurse stations, receptions, and patient rooms. RESULTS: The A-weighted equivalent noise level, L(Aeq), ranges from 54 to 56 dBA, which is at least 10 dB lower than the noise levels of 65 to 73 dBA measured in American ERs. In an ICU, the noise level for the first night was 66 dBA, which came down to 56 dBA for the next day. The noise levels during three different ear surgeries vary from 57 to 62 dBA, depending on the use of surgical drills and suctions. The noise levels in a patient room is found to be 47 dBA, while the nurse stations and the receptions have high noise levels up to 64 dBA. The reverberation times in an operation room, examination room, and single patient room are found to be below 0.6 s. CONCLUSIONS: At SNUH, the nurse stations and receptions were found to be quite noisy. The ERs were quieter than in the previous studies. The measured reverberation times seemed low enough but some other nurse stations and examination rooms were not satisfactory according to the questionnaire.

The effects of polishing technique and brushing on the surface roughness of acrylic resin / 대한치과보철학회지

PURPOSE: This study evaluated the effect of polishing techniques on surface roughness of polymethyl methacrylate (PMMA), as well as the influence of light-cured surface glaze and subsequent brushing on surface roughness. MATERIALS AND METHODS: A total of 60 PMMA specimens (10x10x5 mm) were made and then divided into 6 groups of 10 each according to the polymerization methods (under pressure or atmosphere) and the surface polishing methods (mechanical or chemical polishing) including 2 control groups. The mechanical polishing was performed with the carbide denture bur, rubber points and then pumice and lathe wheel. The chemical polishing was performed by applying a light-cured surface glaze (Plaquit(R); Dreve-Dentamid GmbH). Accura 2000(R), a non-contact, non-destructive, optical 3-dimensional surface analysis system, was used to measure the surface roughness (Ra) and 3-dimensional images were acquired. The surface roughness was again measured after ultrasonic tooth brushing in order to evaluate the influence of brushing on the surface roughness. The statistical analysis was performed with Mann-Whitney test and t-test using a 95% level of confidence. RESULTS: The chemically polished group showed a statistically lower mean surface roughness in comparison to the mechanically polished group (P = .0045) and the specimens polymerized under the atmospheric pressure presented a more significant difference (P = .0138). After brushing, all of the groups, except the mechanically polished group, presented rougher surfaces and showed no statistically significant differences between groups. CONCLUSION: Although the surface roughness increased after brushing, the chemical polishing technique presented an improved surface condition in comparison to the mechanical polishing technique.

A Case of Marfan Syndrome with Subacute Bacterial Endocarditis

Marfan syndrome is a hereditary disorder of connective tissue fibers, involving skeleton, eye and cardiovascular system. The cardiovascular complications, directly related to the cause of death, are associated with about 90% of the Marfan syndrome. The cardiovascular complications are aortic and mitral insufficiency, mitral valvular prolapse, bacterial endocarditis, arrhythmia and aneurysm of interatrial septum and aorta. Among the cardiovascular complications, bacterial endocarditis is unusual. The aortic valve, though commonly abonormal in Marfan syndrome, was rarely involved by endocarditis. In contrast the mitral valve was the favoured site of infection in these patients. The low incidence of aortic valve involvement remains unexplained. There is extreme mortality in Marfan patients affected by endocarditis. A 22-year-old man was admitted to Wallace Memorial Baptist Hospital because of intermittent fever with chill, dyspnea and orthopnea. He had characteristic Marfanoid features such as a slender body with sparsity of subcutaneous fat, arachnodactly and disproprtionate long extremities, axial myopia as well as suspicious family history. Three blood cultures produced a slowly growing gamma-hemolytic streptococcus sensitive to penicillin. Chest X-ray revealed increased C-T ratio and generalized congested lung parenchyme and increased lung markings with multiple dense, horizontal lines, so called Kerley's B lines. Echocardiogram showed thickened bicuspid arotic valve with vegetation and enlarged left ventricular cavity, grade 3/4 mitral and aortic regurgitation. The authors have experienced a rare case of Marfan syndrome with subacute infective endocarditis.