Physicochemical aspects and efficiency of albuterol nebulization: comparison of three aerosol types in an in vitro pediatric model.

BACKGROUND: Advances in nebulizer design have produced both ultrasonic nebulizers and devices based on a vibrating mesh (vibrating mesh nebulizers), which are expected to enhance the efficiency of aerosol drug therapy. The aim of this study was to compare 4 different nebulizers, of 3 different types, in an in vitro model using albuterol delivery and physical characteristics as benchmarks. METHODS: The following nebulizers were tested: Sidestream Disposable jet nebulizer, Multisonic Infra Control ultrasonic nebulizer, and the Aerogen Pro and Aerogen Solo vibrating mesh nebulizers. Aerosol duration, temperature, and drug solution osmolality were measured during nebulization. Albuterol delivery was measured by a high-performance liquid chromatography system with fluorometric detection. The droplet size distribution was analyzed with a laser granulometer. RESULTS: The ultrasonic nebulizer was the fastest device based on the duration of nebulization; the jet nebulizer was the slowest. Solution temperature decreased during nebulization when the jet nebulizer and vibrating mesh nebulizers were used, but it increased with the ultrasonic nebulizer. Osmolality was stable during nebulization with the vibrating mesh nebulizers, but increased with the jet nebulizer and ultrasonic nebulizer, indicating solvent evaporation. Albuterol delivery was 1.6 and 2.3 times higher with the ultrasonic nebulizer and vibrating mesh nebulizers devices, respectively, than with the jet nebulizer. Particle size was significantly higher with the ultrasonic nebulizer. CONCLUSIONS: The in vitro model was effective for comparing nebulizer types, demonstrating important differences between nebulizer types. The new devices, both the ultrasonic nebulizers and vibrating mesh nebulizers, delivered more aerosolized drug than traditional jet nebulizers.

Comparing potentially avoidable hospitalization rates related to ambulatory care sensitive conditions in Switzerland: the need to refine the definition of health conditions and to adjust for population health status.

BACKGROUND: Regional rates of hospitalization for ambulatory care sensitive conditions (ACSC) are used to compare the availability and quality of ambulatory care but the risk adjustment for population health status is often minimal. The objectives of the study was to examine the impact of more extensive risk adjustment on regional comparisons and to investigate the relationship between various area-level factors and the properly adjusted rates. METHODS: Our study is an observational study based on routine data of 2 million anonymous insured in 26 Swiss cantons followed over one or two years. A binomial negative regression was modeled with increasingly detailed information on health status (age and gender only, inpatient diagnoses, outpatient conditions inferred from dispensed drugs and frequency of physician visits). Hospitalizations for ACSC were identified from principal diagnoses detecting 19 conditions, with an updated list of ICD-10 diagnostic codes. Co-morbidities and surgical procedures were used as exclusion criteria to improve the specificity of the detection of potentially avoidable hospitalizations. The impact of the adjustment approaches was measured by changes in the standardized ratios calculated with and without other data besides age and gender. RESULTS: 25% of cases identified by inpatient main diagnoses were removed by applying exclusion criteria. Cantonal ACSC hospitalizations rates varied from to 1.4 to 8.9 per 1,000 insured, per year. Morbidity inferred from diagnoses and drugs dramatically increased the predictive performance, the greatest effect found for conditions linked to an ACSC. More visits were associated with fewer PAH although very high users were at greater risk and subjects who had not consulted at negligible risk. By maximizing health status adjustment, two thirds of the cantons changed their adjusted ratio by more than 10 percent. Cantonal variations remained substantial but unexplained by supply or demand. CONCLUSION: Additional adjustment for health status is required when using ACSC to monitor ambulatory care. Drug-inferred morbidities are a promising approach.