PURPOSE: To perform an economic evaluation of the different treatment methods available for primary open-angle glaucoma in a Korean setting, including medication, selective laser trabeculoplasty, or surgery. METHODS: Three independent Markov chains were constructed for each treatment option to simulate treatment progress and to evaluate the total treatment costs for each initial strategy. The Markov chain consisted of different stages (5, 10, 20 stages), with each stage being one year. Assuming 1000 patients, a Monte Carlo simulation was iterated 1000 times to evaluate the cost of treatment over 5, 10 and 20 years. RESULTS: During the initial five years, medication as the initial treatment was the most expensive, whereas laser trabeculoplasty was the cheapest. After ten years, surgery became the cheapest treatment. In ten years, if the success rate of surgery is greater than 30.1%, it was more economic to choose surgery as the initial treatment. For laser trabeculoplasty, if the success rate was greater than 16.3%, laser treatment was more economical than was medication. Our model shows that only if the annual cost of medication decreases to 60,000 won or 55,000 won, then the cost of choosing medication as the initial treatment strategy will be more economical than that of laser therapy or surgery, respectively. CONCLUSIONS: The economic value of choosing laser therapy as the initial treatment strategy is the greatest over five simulated-years, whereas surgery had the greatest economic value over more than ten years.
Glaucoma ; Glaucoma, Open-Angle ; Health Care Costs ; Humans ; Laser Therapy ; Markov Chains ; Trabeculectomy

BACKGROUND: Application of PEEP increases lung volume and improves oxygenation. High PEEP levels may cause alveolar overdistension or barotrauma. It was hypothesized that there will be an effect of level of PEEP on respiratory resistance and an effect of ventilatory mode on respiratory compliance. This study aimed to investigate the effects of ventilation modes and levels of PEEP on respiratory mechanics during controlled ventilation under general anesthesia. METHODS: In 14 mechanically ventilated patients without cardiopulmonary symptoms and signs, we measured the respiratory mechanics using the inspiration interrupter technique during a constant flow. Dynamic and static compliance, airway resistance, visco-elastic tissue and total respiratory system resistance were calculated at 0, 5, 10, 15, and 20 cmH2O of positive end-expiratory pressure (PEEP) in VCV mode, VCV with inspiratory pause mode, and PCV mode, respectively. RESULTS: The dynamic compliance of the PCV mode was higher than that of the VCV mode. The highest static compliance was at 10 cmH2O PEEP. At 20 cmH2O PEEP, pulmonary compliance was decreased and the tissue resistance was increased. CONCLUSIONS: These results suggest that the respiratory mechanics including respiratory resistance should be monitored for applying PEEP. Further studies on clinical condition such as acute lung injury and ARDS were needed.
Acute Lung Injury ; Airway Resistance ; Anesthesia, General* ; Barotrauma ; Compliance ; Humans ; Lung ; Oxygen ; Positive-Pressure Respiration ; Respiration, Artificial ; Respiratory Mechanics* ; Respiratory System ; Ventilation*

OBJECTIVE: In this study, the exposure levels of polycyclic aromatic hydrocarbons (PAHs) and urinary 1-hydroxypyrene(1-OHP) were surveyed among the workers using coal tar paint. METHOD: The study subjects for the exposed group were 107 male coal tar workers in 10 factories, and for the comparison group were 201 male clerk workers who had never been exposed to coal tar paint. Ambient PAHs, and pre-shift and end-shift urinary 1-OHP were sample and 16 PAHs were analysed. Smoking history was recorded during the survey day. RESULTS: The geometric mean of ambient concentration of total PAHs was 120.17 microgram/m3. Naphthalene had the highest level among the 16 PAHs. The pre-shift 1-OHP in the exposed group (8.89 micro mol/mol creatinine) was significantly higher than that in the control group (0.29 micro mol/mol creatinine). The end-shift 1-OHP in the exposed group (19.02 micro mol/mol creatinine) was significantly higher than that in the pre-shift (8.89 micro mol/mol creatinine) (Ed- confirm). 1-OHP of smokers was significantly higher than that of non-smokers in both groups. The difference between pre-shift and end-shift 1-OHP in smokers (12.40 micro mol/mol creatinine) was twice as high as that in non-smokers (6.06 micro mol/mol creatinine). The difference of 1-OHP between smokers and nonsmokers was 7.59 micro mol/mol creatinine in pre-shift and 13.96 micro mol/mol creatinine in end-shift. Thus, the effect of smoking and exposure to PAHs on 1-OHP may not be additive. In regression analysis for 1-OHP, the significant independent variables were pre-shift 1-OHP and PAHs. The direction of these variables was positive. When the analysis was performed in workers exposed to higher PAHs, smoking was significant independent variable. CONCLUSION: The above results suggest that not only ambient PAHs but also smoking, one of the most important non-occupational PAHs source, influenced the level of 1-OHP. Moreover, the effect of smoking to 1-OHP changed according to the exposure level of PAHs.
Coal Tar* ; Coal* ; Creatinine ; Humans ; Male ; Paint* ; Polycyclic Hydrocarbons, Aromatic* ; Smoke ; Smoking