Efficacy of salbutamol by nebulizer versus metered dose inhaler with home-made non-valved spacer in acute exacerbation of childhood asthma.

This study was done to evaluate and to compare the efficacy of jet nebulizer and metered dose inhaler (MDI) with home-made non-valved spacer (HM NVS) to deliver aerosolized salbutamol in acute exacerbation of asthma in children. HM NVS was made by 500ml plastic mineral water bottle. It was perforated at the bottom for the insertion of MDI and proximal end was cut for placing the mouth. This prospective randomized study was conducted in the department of Pediatrics, Dhaka Medical College Hospital, during April 2007 to March 2008 with 50 known cases (2-12 years) of bronchial asthma with acute exacerbation. After randomized enrollment, each patient received three doses of salbutamol either through a jet nebulizer or through a HM NVS. Oxygen saturation (SaO2), wheeze, heart rate, respiratory rate were recorded throughout the treatment period. Data were analyzed with SPSS for Windows 10.0 at p value <0.05 was considered significant. The mean age of patients was 59.8 months in nebulizer group versus 69.4 months in MDI with HM NVS group. Baseline clinical characteristics in nebulizer group were SaO2 87.7±2.5 versus 89.0±1.8 percent, RR 59.2±7.3 vs. 63.2±4.8 per minute, HR 155.4±11.8 versus 149.0±10.8 per minute and wheeze in 22(88.0%) cases versus 21(84.0%) cases respectively (p>0.05). After therapy improvement was noted among the nebulizer group (SaO2 87.7±2.5 vs. 94.3±2.8 percent; RR 59.2±7.3 vs. 39.3±4.9 per minute; HR 155.4±11.8 vs. 151.60±17.3 per minute; wheeze 88% vs. 8%) as well as in the MDI with HM NVS group (SaO2 89.0±1.8 vs. 94.8±1.8 percent; RR 63.2±4.8 vs. 38.7±6.4 per minute; HR 149.0±10.8 vs. 144.5±13.5 per minute; wheeze 84% vs. 16%) [p<0.001; CI:95%]. However, these improvements did not differ significantly between the nebulizer group and HM NVS group (SaO2 94.3±2.8 vs. 94.8±1.8 percent, RR 39.3±4.9 vs. 38.7±6.4 per minute, HR 151.60±17.3 vs. 144.5±13.5 per minute and wheeze persisted in 2(8.0%) cases versus 4(16.0%) cases respectively) [p>0.05]. The overall response to these modalities of treatment was satisfactory in nebulizer (19/25) and HM NVS (17/25). Salbutamol delivered through both nebulizer as well as MDI with HM NVS is equally effective in the treatment of acute asthma in children.

Initial evaluation of commercial optical CT-based 3D gel dosimeter.

We evaluated the OCTOPUS-ONE research laser CT scanner developed and manufactured by MGS Research, Inc. (Madison, CT). The scanner is designed for imaging 3D optical density distributions in BANG gels. The scanner operates in a translate-rotate configuration with a single scanning laser beam. The rotating cylindrical gel phantom is immersed in a refractive index matching solution and positioned at the center of a square tank made of plastic and glass. A stationary polarized He-Ne laser beam (633 nm) is reflected from a mirror moving parallel to the tank wall and scans the gel. Another mirror moves synchronously along the opposite side of the tank and collects the transmitted light and sends it to a single stationary silicon photodetector. A filtered backprojection algorithm is used to reconstruct projection data in a plane. The laser-mirrors-detector assembly is mounted on a horizontal platform that moves vertically for slice selection. We have tested the mechanical and optical setup, projection centering on the axis of rotation, linearity, and spatial resolution. We found the optical detector to respond linearly to transmitted light from control samples. The spatial resolution of the scanner was determined by employing a split field resolution technique. We obtained the horizontal and vertical full widths at half maxima of the laser beam intensity profiles as 0.6 and 0.8 mm, respectively. Dose calibration tests of the gel were performed using a nine-field (2 x 2 cm2 each) dose pattern irradiated at different dose levels. Finally, we compared gel-derived 2D planar dose distribution against radiochromic film measured dose distribution for both the nine-field and a uniform 5 x 5 cm2 field of 6 MV x rays. Very similar dose distributions were observed in gel and radiochromic film except in regions of steep dose gradient and highest dose. A dose normalization of 15.6% was required between the two dosimeters due to differences in overall radiation response. After normalization, analysis using the gamma evaluation showed that the radiochromic film and gel-measured dose distributions differed by a maximum gamma of 1.3 using 5% and 1.5 mm dose difference and distance-to-agreement criteria. The optical CT scanner has great potential as a 3D dosimeter, but a few refinements and further testing are necessary before its routine clinical use.

The effects of ambient air pollution on school absenteeism due to respiratory illnesses.

We investigated the relations between ozone (O3), nitrogen dioxide (NO2), and respirable particles less than 10 microm in diameter (PM10) and school absenteeism in a cohort of 4th-grade school children who resided in 12 southern California communities. An active surveillance system ascertained the numbers and types of absences during the first 6 months of 1996. Pollutants were measured hourly at central-site monitors in each of the 12 communities. To examine acute effects of air pollution on absence rates, we fitted a two-stage time-series model to the absence count data that included distributed lag effects of exposure adjusted for long-term pollutant levels. Short-term change in O3, but not NO2 or PM10, was associated with a substantial increase in school absences from both upper and lower respiratory illness. An increase of 20 ppb of O3 was associated with an increase of 62.9% [95% confidence interval (95% CI) = 18.4-124.1%] for illness-related absence rates, 82.9% (95% CI = 3.9-222.0%) for respiratory illnesses, 45.1% (95% CI = 21.3-73.7%) for upper respiratory illnesses, and 173.9% (95% CI = 91.3-292.3%) for lower respiratory illnesses with wet cough. The short-term effects of a 20-ppb change of O3 on illness-related absenteeism were larger in communities with lower long-term average PM10 [223.5% (95% CI = 90.4-449.7)] compared with communities with high average levels [38.1% (95% CI = 8.5-75.8)]. Increased school absenteeism from O3 exposure in children is an important adverse effect of ambient air pollution worthy of public policy consideration.