雾化吸入文献-1

Deposition and dispersion of aerosols in the airways of the human respiratory tract: the effect of
particle size
Authors: G Scheuch, W Stahlhofen
Small volumes of aerosols (boluses) were inspired predominantly into the conducting airways of human lungs with a fast operating valve system, injecting preselected aerosol volumes near the end of a clean air inhalation. Particle recovery and bolus dispersion in the exhaled air after various periods of breathholding were investigated by measuring aerosol number concentration directly in front of the mouth with a laser photometer. Inspired and expired flow rates were measured with a pneumotachograph. The effect of particle size on these measurements has been investigated using aerosol particles with aerodynamic diameters (dae) between 0.9 and 5 microns. For aerosol particles smaller than 2 microns, bolus dispersion increases with increasing periods of breathholding (tb). After reaching a maximum, dispersion decreases with even longer tb. An increase in particle size yields a smaller increase in dispersion during the first seconds of breathholding while it is not changed significantly without breathhold. Particle losses during inhalation and exhalation increases with particle size. However, with increasing periods of breathholding, the losses of the smaller particles (less than 1.5 microns) were found to be much higher than expected theoretically, implying particle losses by sedimentation in the same airway structures. The small aerosol particles are deposited in smaller airways than bigger particles. These observations can be explained by cardiogenic mixing during periods of breathholding by pulsatile flow oscillations and confirm measurements with enhanced heart rate as described in an earlier paper. Small particles with restricted settling velocities remained longer in an airborne state in the airways and this leads to a more efficient cardiogenic mixing. Experimental lung research. 18(3):343-58.
ISSN: 0190-2148
Comparison of three commercial ultrasonic nebulizers
Authors: R K Katial, C Reisner, A Buchmeier, B B Bartelson, H S Nelson
BACKGROUND: The clinical acceptance of the initial ultrasonic nebulizers was impeded by their production of significant quantities of droplets larger than the respirable range that could have resulted in poor pulmonary deposition of nebulized medications. Subsequent modifications in the design of ultrasonic nebulizers have occurred. Overall nebulizer performance characteristics of the newer ultrasonic devices have not been evaluated. OBJECTIVE: Three commercially available ultrasonic nebulizers (DeVilbiss-Pulmosonic, Omron-Microair, Rh.ne
Poulenc-Rorer-Fisoneb) were studied to compare the aerosol output characteristics. METHODS: The parameters studied were total volume output (TVO), time to nebulize total output (TTO), percent of droplets with volume diameters in the respirable range (PDVRR, 1 to 5 microm), albuterol concentration during nebulization, and the total drug delivered. All nebulizers were filled with 2.5 mL of saline and 0.5 mL of albuterol nebulizer solution. Three units from each manufacturer, each from a different lot, were evaluated in duplicate. RESULTS: The nebulizer with the largest volume output was the Omron (mean 2.94 mL), which also demonstrated the longest nebulization time (mean 10.3 min). The DeVilbiss and Rh.ne Poulenc-Rorer units delivered smaller volumes (mean 2.5 mL, 2.4 mL, respectively) but nebulized more rapidly (mean 2.21 min, 3.54 min, respectively). The Omron nebulizer generated the highest PDVRR with a mean of 38%. The DeVilbiss had a mean PDVRR of 16% and the Rh.ne Poulenc-Rorer a mean PDVRR of 21%. The majority of droplets from all three machines had a volume diameter smaller than the respirable range, ie, in the 0.5 to 1.0 microm range (Omron-60%, DeVilbiss-83%, Rh.ne Poulenc-Rorer-79%). For all three nebulizers there appeared to be no concentrating or diluting effect during nebulization implying that equal quantities of albuterol and diluent were delivered. The Rh.ne Poulenc-Rorer units demonstrated the greatest unit-to-unit variability with respect to TVO while the Omron units demonstrated the greatest unit to unit variability with respect to TTO. CONCLUSION: We conclude that several improvements in the design of ultrasonic nebulizers have resulted in the reduction of the size of the droplets generated. Our evaluation of the three commercially available ultrasonic nebulizers revealed that the majority of droplets generated were within or below the respirable range. There was no concentrating or diluting effect during nebulization for all three nebulizers. The output characteristics of the three devices differ and this will effect the delivery time as well as amount of drug delivered to the lungs.
Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, &
Immunology. 01/03/2000; 84(2):255-61.
ISSN: 1081-1206
The function profile of compressed-air and ultrasonic nebulizers Authors: Hsin-Lin Wu, Yung-Zen Lin, W ei-Fong Wu, Fu-Yuan Huang
In order to study the detailed function of two kinds of nebulizers commonly used in clinical asthma treatment, compressed-air and ultrasonic, this study was conducted. At the beginning, various flow rates were adjusted, paired with different volumes of solutions in the container. The changes of temperature, pH, and osmolality during the course of nebulization were examined. Normal saline, terbutaline, and fenoterol solutions were used as the nebulized solutions. The study was performed in an environment in ambient temperature around 20 degrees C and relative humidity around 70%. The results showed a minimal 6 L/min flow rate was required to nebulize the solution when using the compressed-air nebulizer. The dead volume was about 0.8 ml for compressed-air and 8.5 ml for the ultrasonic nebulizer. When using the compressed-air nebulizer, the temperature, both in the solution and at the mouthpiece site, dropped gradually. On the contrary, the temperatures at both sites increased a little bit when using the ultrasonic nebulizer. The pH values of pure terbutaline and fenoterol nebulized solutions were acidic (3.58 and 3.00 respectively). The osmolality of terbutaline and fenoterol nebulized solutions were isotonic. The osmolality increased gradually during the course of nebulization, to a greater extent in the compressed-air nebulizer. In conclusion, both types of nebulizers have their special features. The ultrasonic nebulizer displays less extent in change of temperature and osmolality during nebulization and is expected to be a better device in treating asthmatic patients in terms of lesser effect on cooling and changing the osmolality of airway mucosa. Acta paediatrica Taiwanica = Taiwan er ke yi xue hui za zhi.
44(5):264-8.
ISSN: 1608-8115。