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PubMed1994

Behavior of nebulizing solutions and suspensions.

A compressed air source is needed to run a jet nebulizer; its operating pressure affects the aerosol flow through the nebulizer, the quantity of drug and/or solution leaving the nebulizer, and the droplet size. With increasing pressure, the output (gravimetric change during nebulization) will increase and the droplet size decrease. The temperature of the nebulizing solution will decrease by as much as 10 degrees C due to energy loss from evaporation of droplets. Other important considerations in nebulizer therapy are taste, pH and viscosity of the solution. For those drugs which cannot be dissolved, the nebulizing behavior is different. In nebulizing suspensions, the drug particles must be micronized to a mass median diameter of 1-2mum to give optimal output conditions from jet nebulizers with a droplet size of 3mum mass median diameter. The solid drug particles leave the nebulizer through the medium of the droplets, and when a solid drug particle is larger than the droplet it will become trapped in the nebulizer. This has been illustrated in a separate experiment in which 0.5mg/ml budesonide was nebulized from eight different nebulizers. The droplet size as well as the output--calculated from the quantity of drug remaining in the nebulizer after 10 min nebulization--varied with type of nebulizer. A preferable way of determining drug delivery to a patient is to collect the aerosol on a filter during normal breathing and then analyse the drug content on the filter.(ABSTRACT TRUNCATED AT 250 WORDS)

Aerosols↗

PubMed2003

Comparison of two methods of delivering continuously nebulized albuterol.

OBJECTIVE: To compare the relative delivery of 2 methods for providing continuously nebulized albuterol (CNA): a small-volume nebulizer plus infusion pump versus a large-volume nebulizer. DESIGN: An open, randomized comparison of 3 hours of CNA administration using an in vitro lung model with a follow-up particle size assessment of the large-volume nebulizer. METHODS: Six different nebulizers of each type were connected to a lung model via a volume-limited mechanical ventilator and infant ventilator circuitry. Albuterol was nebulized at 10 mg/h for 3 hours in random order. The small-volume nebulizer used was the Airlife Misty Neb (Baxter, Valencia, CA); the large-volume nebulizer was the HEART Nebulizer (Vortran Medical, Orangevale, CA). One large-volume nebulizer was operated over 8 hours for the output and particle sizing study. RESULTS: The small-volume nebulizer delivered a greater amount of albuterol (mean +/- SD percentage of total nebulized) to the model lung (5.75 +/- 1.38% vs. 4.12 +/- 0.67%; p < 0.025) than the large-volume nebulizer, but demonstrated greater variability. Although total output was not maintained after 8 hours of nebulization with the large-volume nebulizer, the percent of particles in the respirable range remained consistent. CONCLUSIONS: The large-volume nebulizer evaluated in this study maintains consistent output up to 8 hours and provides an acceptable method for delivering CNA through an infant ventilator circuit.

Administration, Inhalation↗

PubMed1997

Measuring nebulizer output. Aerosol production vs gravimetric analysis.

STUDY OBJECTIVES: The function of jet nebulizers has been measured traditionally by gravimetric methods, i.e., by weighing nebulizers before and after nebulization. Newer techniques measure aerosol output directly by analyzing aerosolized drug or tracer, i.e., radioactive 99mTc. Because of evaporation, the equivalence of these methods is uncertain. The aim of this study was to determine if the gravimetric method is an accurate measure of aerosol production under different conditions of aerosol generation (i.e., nebulizer type, flow rate, pressure, volume fill, and concentration of solution used to nebulize a drug). METHODS: In the first phase of the study, we measured the aerosol output of nine commercially available jet nebulizers (AvaNeb; Up-Draft-Hudson RCI; Cirrus-Intersurgical Inc; DeVilbiss 646-DeVilbiss; Powermist-Hospitak, Inc; Respirgard II-Marquest Medical Products; Seamless-Seamless/Dart Respiratory; Salter; Salter Labs; Airlife-Baxter Health Care) run under commonly used conditions (2.5 mL volume fill, 2.0 mL normal saline solvent, 0.5 mL albuterol, flow of 6 L/min, and pressures averaging 15.0 +/- 2.3 [mean +/- SD] pounds per square inch [on the] gauge [psig] provided by a DeVilbiss PulmoAide compressor) with simultaneously measured gravimetrics and filtered radioactivity. Each nebulizer was run to dryness with data acquired every 2 min. The change in the weight of the nebulizer and radioactivity captured on the filter were expressed as percentages of the total in the nebulizer solution. In the second phase of the study, the experiments were repeated using the same nebulizers with a volume fill of 5 mL (diluted to half normal saline solution plus albuterol), flow of 10 L/min, and pressures of 35.6 +/- 8.8 psig. RESULTS: The cumulative (sum of all 2-min runs) weight loss for each individual nebulizer ranged from 25.00 to 64.55% and cumulative aerosol captured varied from 12.63 to 38.76%. While different, the weight loss and aerosol captured were closely correlated (y = -0.62 + 0.62x; r = 0.961, p < 0.0001). Changing volume fill and concentration of solvent did not affect this correlation (p = 0.921 and 0.373, respectively). However, changing flow from 6 L/min to 10 L/min significantly (p = 0.02) affected the relationship (y = -3.80 + 0.83x; r = 0.969, p < 0.001). CONCLUSIONS: When compared with direct methods such as filtering generated particles, the gravimetric method of assessing nebulizer function overestimates aerosol output by 1.8 +/- 0.18 times, presumably because of the loss of solvent during nebulization. However, the relationship between methods is predictable and appears unaffected by changing the type of nebulizer, volume fill, and concentration of solvent. Changes in nebulizer flow and pressure significantly affected the correlation. Gravimetric methods can be used as simple and convenient screening techniques for comparing jet nebulizers under a wide range of experimental conditions.

Adrenergic beta-Agonists↗

PubMedDate not supplied

Intranasal deposition of nebulized saline: a radionuclide distribution study.

BACKGROUND: Despite the popularity of various nasal sprays and nebulizers, there are limited data regarding the anatomic distribution of particles generated by these devices. This pilot study sought to characterize distribution patterns of nebulized and sprayed saline particles in normal subjects and postsurgical sinus patients. METHODS: Fifteen subjects were studied in three trials: metered-dose nasal spray bottle versus vortex-propelled nebulizer in normal subjects, passive-diffusion nebulizer versus vortex nebulizer in normal subjects, and passive nebulizer versus vortex nebulizer in postsurgical sinus patients. Radiolabeled saline was administered, and nose, lungs, and stomach were imaged. Images were scored by four blinded reviewers for degree of penetration at nine anatomic subsites. RESULTS: Compared with spray bottle, the vortex nebulizer showed more focal intranasal distribution with reduced nasopharyngeal, pharyngeal, and gastric penetration in normal subjects. Three of five subjects showed probable frontal sinus penetration by vortex nebulizer, but no other sinus penetration was noted. No patients showed sinus penetration with the spray bottle. In a separate trial against the passive nebulizer, the vortex nebulizer again showed a greater tendency for sinus penetration in normal subjects, with three of five showing some degree of sphenoid penetration and one of five showing slight maxillary penetration. In contrast, no sinus penetration was observed with the passive nebulizer. In the postsurgical patient cohort, minimal sinus penetration was noted with either the vortex nebulizer or the passive nebulizer. Despite surgically patent sinuses, only one of five subjects showed any type of sinus penetration. CONCLUSION: The nebulizer and nasal spray devices tested in general showed limited penetration of the sinuses in both normal and postoperative patients. The device showing greatest promise for sinus penetration in normal patients was the vortex nebulizer, with an overall penetration rate in normal patients of 30% in the frontal, 30% in the sphenoid, and 10% in the maxillary. Understanding delivery patterns of topical therapies may be important in evaluating the efficacy of various topical treatment modalities.

Equipment Design↗

PubMed2000

Dispensing home nebulizers for acute wheezing from the hospital is cost-effective.

The objective was to investigate the use characteristics of home nebulizers and to measure the benefit gained from dispensing home nebulizers (compared with their cost) to patients from the hospital. During the study period, August 28,1996 to May 17,1997, a sample of 232 of the 291 entries from a log of home nebulizers dispensed by the hospital respiratory care department were surveyed over the telephone. Of the 232 study subjects under the age of 21, a telephone interview of a guardian or supervising adult was completed in 106 subjects (46%) a mean of 43 weeks after the home nebulizer was prescribed (47% of the cohort received their home nebulizers from the inpatient service and another 47% were discharged with home nebulizers from the emergency department (ED)). An average of 3.6 estimated additional ED visits and 5.4 office/clinic visits for each patient were prevented by the home nebulizer. The benefit (savings from reduced ED and office visits alone) to cost ratio estimates range from $855:$90 to $1710:$90 or more. The overwhelming majority of the patients felt that the home nebulizer was a good idea, it was easy to use, they had no problems with the nebulizer and they received adequate training for home nebulizer use. Home nebulizers are a cost-effective means of providing home nebulized albuterol for selected outpatients. Hospital inpatient units and EDs which have the ability to dispense a home nebulizer, have an additional therapeutic option available for selected patients who may benefit from it. Medical insurance companies should fully support (ie, pay for) home nebulizers because it is cost effective. If there is any concern about the reliability of the patient to follow-up with their primary physician, the patient's primary physician should be contacted to discuss the feasibility of discharging the patient with a home nebulizer.

Acute Disease↗

PubMed1996

A long-term study of symptoms, spirometry and survival amongst home nebulizer users.

Although home nebulizers are widely used to deliver bronchodilator medication to patients with asthma and chronic obstructive pulmonary disease (COPD), the long-term benefits and hazards are unknown. The present authors have previously reported a prospective 12-month study of home nebulizer use involving 49 patients (15 asthma, mean forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) 1.3/2.1 1; 34 COPD, mean FEV1/FVC 0.7/1.8 1). Thirty-two of these patients were treated with long-term domiciliary nebulized bronchodilator treatment, the other 17 patients chose metered dose inhaler (MDI) therapy. The present paper reports the progress of these patients over 5 yr. Five-year survival was similar in both groups (nebulizer users 56%, MDI users 53%). Most deaths were due to respiratory failure (14 deaths) or lung cancer (four deaths). Survival was determined mainly by FEV1 (R = 0.54, P = 0.0001) and age (R = -0.47, P = 0.0007). Laboratory lung function tests (16 nebulizer users) showed that FEV1 and FVC were still higher than pre-nebulizer baseline measurements after 36 months of nebulizer use, but PEFR had fallen by 7%. Twenty-one of 23 surviving nebulizer users completed a questionnaire after 36 months of treatment. All used their nebulizer at least once per day and 20 of 21 patients reported that they still obtained full benefit from each nebulized treatment. The morning peak flow response to nebulized treatment was the same at baseline and at 36 months (48 1 min-1). All patients remained breathless (mean subjective score 4.8 on seven-point scale) but the subjective response to nebulized treatment was unchanged at 36 months. Tachyphylaxis did not develop among 13 patients who underwent repeated reversibility studies using 200 micrograms of salbutamol at 6, 12 and 36 months. It is concluded that home nebulizer therapy is safe and effective for a small number of carefully selected patients with severe asthma or COPD, who have been evaluated by a rigorous home nebulizer assessment protocol prior to commencing home nebulizer therapy.

Adult↗

PubMed1998

Ultrasonic nebulization of cationic lipid-based gene delivery systems for airway administration.

PURPOSE: This study relates to the development of gene therapies for the treatment of lung diseases. It describes for the first time the use of ultrasonic nebulization for administration of plasmid/lipid complexes to the lungs to transfect lung epithelial cells. METHODS: Plasmid complexed to cationic liposomes at a specific stoichiometric ratio was nebulized using an ultrasonic nebulizer. We assessed: (i) the stability of plasmid and plasmid/lipid complexes to ultrasonic nebulization, (ii) the in vitro activity of plasmid in previously nebulized plasmid/lipid complex, (iii) the in vivo transgene expression in lungs following intratracheal instillation of nebulized plasmid/lipid formulations compared to un-nebulized complexes, (iv) the emitted dose from an ultrasonic nebulizer using plasmid/lipid complexes of different size, and (v) the transgene expression in lungs following oral inhalation of aerosolized plasmid/lipid complex generated using an ultrasonic nebulizer. RESULTS: Integrity of plasmid formulated with cationic lipids, and colloidal stability of the plasmid/lipid complex were maintained during nebulization. In contrast, plasmid alone formulated in 10% lactose was fragmented during nebulization. The efficiency of transfection of the complex before and after nebulization was comparable. Nebulization produced respirable aerosol particles. Oral exposure of rodents for 10 minutes to aerosol produced from the ultrasonic nebulizer resulted in transgene expression in lungs in vivo. CONCLUSIONS: The performance characteristics of the ultrasonic nebulizer with our optimized plasmid/lipid formulations suggests that this device can potentially be used for administering gene medicines to the airways in clinical settings for the treatment of respiratory disorders.

Aerosols↗

PubMed2000

Jet and ultrasonic nebulization of single chain urokinase plasminogen activator (scu-PA).

Recent studies have indicated that the deposition of intra-alveolar fibrin may play a central role in the pathogenesis of acute respiratory distress syndrome (ARDS). Our aim was to study whether the indigenous fibrinolytic agent (urokinase) normally present in the alveoli can be administered locally by nebulization in a recombinant zymogen form as single chain urokinase plasminogen activator (scu-PA). We aimed to characterize the particle size distribution, drug output, and enzymatic activity of scu-PA after nebulization with a Ventstream jet nebulizer (Medic-Aid, Bognor Regis, UK) and a Syst'AM DP-100 ultrasonic nebulizer (Pulmolink, Kent, UK). The particle size distribution was measured with a laser diffraction method and the drug output was determined by collection on filters. The amount of protein on the filters was determined with the Lowry method, and the enzymatic activity after nebulization was measured with a microtiter fibrin plate assay. The mass median diameter (MMD) of the scu-PA aerosol generated with the ultrasonic nebulizer was 3.69 (3.53-3.83) microm and with the jet nebulizer 2.96 (2.91-3.03) microm (p < 0.001). The drug output from the two nebulizers did not differ between nebulizers (p = 0.054). Fibrinolytically active scu-PA was generated with both nebulizers, but in contrast to jet nebulization, ultrasonic nebulization caused partial inactivation of scu-PA (p < 0.001). In conclusion, nebulization of scu-PA with the jet nebulizer is superior to ultrasonic nebulization in terms of particle size distribution and preservation of fibrinolytic activity.

Aerosols↗

PubMed1999

The effect of heliox on nebulizer function using a beta-agonist bronchodilator.

OBJECTIVE: To evaluate nebulizer performance when heliox was used to power the nebulizer. METHODS: Conventional and continuous nebulizer designs were evaluated. The conventional nebulizer was used with 5 mg albuterol and flows of 8 L/min air, 8 L/min heliox, and 11 L/min heliox; it was also used with 10 mg albuterol and a heliox flow of 8 L/min. The continuous nebulizer was set to deliver 10 mg of albuterol over 40 min at flows of 2 L/min air, 2 L/min heliox, and 3 L/min heliox; it was also used with 20 mg albuterol and a heliox flow of 2 L/min. A cotton plug at the nebulizer mouthpiece was used to trap aerosol during simulated spontaneous breathing. The amount of albuterol deposited on the cotton plug was determined spectrophotometrically. Particle size was determined using an 11-stage cascade impactor. RESULTS: For both nebulizer designs, particle size and inhaled mass of albuterol decreased significantly (p < 0.001) when the nebulizer was powered with heliox rather than air. When powered with heliox, the reduction in inhaled mass of albuterol was less for the conventional nebulizer (16%) than the continuous nebulizer (67%). The nebulization time, however, was more than twofold greater with heliox (p < 0.001). Increasing the flow of heliox increased the particle size (p < 0.05), inhaled mass of albuterol (p < 0.05), and inhaled mass of particles 1 to 5 microm (p < 0.05) to levels similar to powering the nebulizer with air at the lower flow. Increasing the albuterol concentration in the nebulizer and using the lower heliox flow increased the inhaled mass of albuterol (p < 0.05) while maintaining the smaller particle size produced with that flow. CONCLUSIONS: The use of heliox to power a nebulizer affects both the inhaled mass of medication and the size of the aerosol particles. The flow to power the nebulizer should be increased when heliox is used.

Adrenergic beta-Agonists↗

PubMedDate not supplied

The function profile of compressed-air and ultrasonic nebulizers.

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.

Air↗

PubMed1984

Collison 6-jet nebulizer: choice for the certification test of the class II biological safety cabinet.

Three types of nebulizers, one plastic, one glass and Collison 6-jet nebulizers were tested, to select an appropriate nebulizer for the certification of the class II biological safety cabinets (BSC). Performance of the plastic and glass refluxing nebulizers were found to be both inconsistent from one to another, and not provide reproducible results. The Collison nebulizers, on the other hand, showed little variations and provided reproducible results. In addition, the Collison nebulizer generated constant spray volume when the fluid level in the reservoir was varied. To determine optimum discharge velocity of the Collison nebulizer, nebulizers with an outlet diameter of 10, 12, 14, 16 and 18 mm were tested. For the personnel protection test, the main stream of aerosol sprayed from the Collison nebulizer with 14 mm outlet internal diameter hit the intersection of the test cylinder and the front opening. Each nebulizer with an outlet diameter of 12 to 16 mm located at the level of lower edge of the front window delivered aerosols more efficiently at the intersection than when located at 14 inches above the work surface. The aerosol from the 10 or 18 mm diameter nebulizers showed an inappropriate distribution. For the product protection test, the nebulizer with 14 mm outlet diameter showed the best distribution pattern around the test cylinder. In the cross contamination test, this nebulizer outperformed the 10 or 18 mm for class II BSC's without side wall effect. According to these results, the Collison nebulizer with 14 mm of internal diameter nozzle was found appropriate for the biological certification tests of the class II BSC. Exception was the cross contamination test of class II BSC with a side air intake between the internal side wall and the work surface, in which the nebulizer with 10 mm nozzle was the choice.

Aerosols↗

PubMed1999

An in vitro analysis of the output of budesonide from different nebulizers.

BACKGROUND: Inhaled corticosteroids are increasingly used in the treatment of asthma, and many different nebulizers are available to aerosolize steroid medications. There are few comparative data on their ability to do so. OBJECTIVE: Our purpose was to determine the particle size and mass output of budesonide nebulizer suspension from different nebulizers. METHODS: In vitro measurement of drug particle size and total drug output from 3 nebulizers (the Pari LC Plus, the Pari LC Star, and the Medicaid Ventstream) was performed under simulated breathing conditions. Nebulizers were charged with 2 mL (500 microg) of budesonide suspension. A sinus pump was used to draw aerosol from the nebulizers onto a filter during simulated inspiration at tidal volumes of 150 and 600 mL, mimicking pediatric and adult use. Aerosol particle size was determined separately by inertial impaction. RESULTS: The LC Plus nebulizer had the highest initial output rate and delivered the most budesonide at both breathing patterns. The maximal output rates of the Ventstream and LC Star nebulizers was half that of the LC Plus, but the LC Star nebulizer continued nebulization for longer and delivered twice as much budesonide as the Ventstream did. However, the Ventstream produced the smallest particles, mass median diameter 3.1 microm compared with 3.8 microm for the LC Star and 4.1 microm for the LC Plus. CONCLUSIONS: This study has identified differences among the nebulizers that would not have been apparent with current standards for nebulizer assessment. Incorporation of breathing simulation in the study imitates patient use and allows effective nebulization times to be predicted. The results suggest that the nebulizers studied would deliver different masses of budesonide to the lungs and to the upper airway. This may have important consequences in determining the efficacy and side effect profile of budesonide.

Budesonide↗

PubMed1999

Inhalation of tobramycin in cystic fibrosis. Part 1: the choice of a nebulizer.

Forteen commercially available jet and ultrasonic nebulizers were investigated with the aim to select the most suitable type of apparatus for the inhalation of a 10% tobramycin solution. Two different techniques for measurement of particle size distribution were evaluated: laser diffraction and cascade impactor analysis. The final selection of the nebulizers is based on particle size distribution, output and stable performance during nebulization. All 14 nebulizers (eight jet and six ultrasonic) were filled with a solution of 10% m/v tobramycin (as sulphate) in water. The volume in the tested devices ranged from 4.5 to 10 ml (=450-1000 mg tobramycin) in accordance with the prescribed usage by the suppliers. The nebulizers were connected with a special designed adapter to a laser diffraction analyser in order to measure particle size distribution of the aerosol. Inhalation was simulated with a static flow of 40 l/min. The particle size distribution (expressed as X(10), X(50), and X(90)) was determined after 10 s, 1.5, 3, 4.5, 6, 9 and 12 min of nebulization. Furthermore, the tobramycin solutions were assayed for tobramycin content before and after nebulization. For all nebulizers, the mean particle size distribution, depicted as X(50), was within the range of 1-5 mm. There were no relevant differences between the nebulizers in concentration or particle size distribution during nebulization. The output of the nebulizers is a result of both nebulization and evaporation. The output, expressed as volume of tobramycin solution, ranged from 0.06 to 0.50 ml/min. The output of tobramycin ranged from 1.2 to 39.5 mg/min. For clinical practice 300-600 mg have to be nebulized within 20-30 min. It was concluded that only three jet nebulizers [Porta-Neb Sidestream (PNS), Porta-Neb Ventstream (PNV) and Pariboy Pari LC+ (PLC)] have a reasonable output and an acceptable particle size distribution for the administration of a 10% tobramycin solution in the therapeutic dosage range.

Administration, Inhalation↗

PubMed1993

A prospective, randomized study of continuous versus intermittent nebulized albuterol for severe status asthmaticus in children.

OBJECTIVES: a) to determine if continuous nebulization of albuterol is more effective than intermittent nebulization in the treatment of children with status asthmaticus and impending respiratory failure; b) to determine the effect of continuous nebulization and intermittent nebulization on duration of hospital stay and bedside respiratory therapy care. DESIGN: Prospective, randomized study. SETTING: A pediatric intensive care unit (ICU) in a university children's hospital. PATIENTS: Seventeen pediatric asthmatic patients with severe status asthmaticus, with impending respiratory failure (Woods asthma score > or = 5), and without evidence of cardiac or other preexisting lung disease were admitted to the pediatric ICU. The patients were randomized to receive continuous nebulization (n = 9) or intermittent nebulization (n = 8) of albuterol. INTERVENTIONS: The asthmatic patients were randomized into two groups. The continuous group received 0.3 mg/kg/hr of albuterol by continuous nebulization; the intermittent group received 0.3 mg/kg of albuterol over 20 mins every hour. All patients received aerosol therapy through the same delivery system. MEASUREMENTS: Responses to therapy were evaluated by following asthma score, arterial blood gas values, hemodynamics, FIO2, and arterial oxygen saturation initially and at 30 mins, 1 hr, 2 hrs, 4 hrs, then every 4 hrs for a 24-hr time period. Patients were determined to no longer be in impending respiratory failure when their asthma score was < 5 for four consecutive hours. Electrocardiograms, serum electrolyte values, and creatine phosphokinase total and MB fraction values were obtained before and after treatment. Hospital stay and respiratory therapy time, in relative value units (one relative value unit = 10 mins) were analyzed from data collected from therapist bedside flow sheets. RESULTS: The patient characteristics (demographics, hemodynamics, arterial blood gas values, asthma severity, corticosteroid use, theophylline, and beta 2-adrenergic receptor agonist administration) before entry into the study did not differ between groups. Patients in the continuous group improved more rapidly and were out of impending respiratory failure sooner than patients in the intermittent group (continuous group = 12 (median) hrs (range 4 to 24) vs. intermittent group = 18 (median) hrs (range 12 to 24; p = .03). Bedside respiratory therapy time evaluated by relative value units was less for patients who received continuous nebulization of albuterol (continuous group = 14 (median) relative value units (range 6 to 26) vs. intermittent group = 33 (median) relative value units (range 25 to 49; p = .001). Hospital stay was shorter for patients who received continuous nebulization of albuterol (continuous group = 80 [median] hrs [range 51 to 173] vs. intermittent group = 147 [median] hrs [range 95 to 256]; p = .043). Hemodynamics, serum potassium, and creatine phosphokinase concentrations did not differ before and after the study in either group. CONCLUSIONS: In children with impending respiratory failure due to status asthmaticus, continuous nebulization of albuterol is safe and results in more rapid clinical improvement than intermittent nebulization. Respiratory therapy required at the bedside and duration of hospital stay were substantially less for patients receiving continuous nebulization of albuterol, which suggests that continuous nebulization of albuterol is more cost effective than intermittent nebulization.

Adolescent↗

PubMed1998

A new method for measuring aerosol nebulizer output using radioactive tracers.

Reproducibility and comparability of bronchial challenge tests depends critically on accurate assessment of nebulizer output. Evaporation during nebulization means that simple weighing is inaccurate, overestimating the delivered dose of active ingredient. We wanted to quantify this effect in the context of intermittent nebulization, using a dosimeter as used in bronchial provocation tests. Output of three types of nebulizer, from the MEFAR dosimeter, was measured by radioactive tracer, using a standard solution of technetium-99m-pertechnetate (1.5 kBq x mL(-1)) in 4 mL of normal saline. The aerosol was impacted by suction onto a microfilter, and the radioactivity measured. Nebulizers were weighed before and after nebulization. Ratio of nebulized volume calculated from the radioactivity on the filter, to the total volume loss by weight, was expressed as nebulized ratio. The effect on output of two concentrations of methacholine, two tracers of different weights, and change in temperature, were assessed. Nebulized ratio varied between 44.1-71.6%. Results were more consistent within the same type of nebulizer than between different makes. Neither changes in molar concentration nor molecular weight affected nebulizer output or nebulized ratio. Mean nebulized ratio was 58.5%, showing that calibration by weighing, overestimates the delivered dose by a factor of approximately two. Measuring radioactivity eluted from a microfilter, onto which nebulized output had been impacted proved to be a satisfactory method of calibration.

Aerosols↗

PubMed2002

Comparison of sputum induction using high-output and low-output ultrasonic nebulizers in normal subjects and patients with COPD.

STUDY OBJECTIVE: s: Induced sputum is used to investigate pulmonary diseases. Low-output ultrasonic nebulizers have become available and have potential advantages over high-output nebulizers. We hypothesized that a low-output nebulizer would give comparable results to a high-output nebulizer, with an acceptable safety profile. DESIGN: Randomized, crossover study. SETTING: University teaching hospital. PARTICIPANTS: Ten normal subjects and 10 patients with COPD. INTERVENTIONS: Participants attended for sputum induction on two occasions in random order using low-output and high-output nebulizers. MEASUREMENTS AND RESULTS: Lung function and oxygen saturation were measured during sputum induction, and tolerability of the procedure was assessed. Cell counts, interleukin 8, and neutrophil elastase were measured in sputum. Use of the high-output nebulizer resulted in a greater FEV(1) (mean +/- SEM, 0.29 +/- 0.04 L vs 0.21 +/- 0.04 L; p = 0.04) and percentage drop in FEV(1) (25.8 +/- 2.6% vs 19.5 +/- 2.9%, respectively; p = 0.02) compared with the low-output nebulizer in patients with COPD. There was a shorter tolerated nebulization time with the high-output nebulizer compared with the low-output nebulizer: 12.7 +/- 2.0 min vs 16.5 +/- 1.8 min, respectively (p = 0.02). Modified Borg scores were lower with the low-output nebulizer than the high-output nebulizer in normal subjects: median, 0 (interquartile range [IQR], 0 to 1) vs median, 1.5 (IQR, 0 to 2), respectively (p = 0.05). There were no differences in cell counts and soluble markers of inflammation. CONCLUSIONS: The low-output ultrasonic nebulizer is comparable to high-output nebulizer for cellular and soluble markers of inflammation, results in a smaller reduction in FEV(1), is better tolerated, and is a suitable tool for investigating airway inflammation in patients with COPD.

Adult↗

PubMed1997

Comparison of jet and ultrasonic nebulizer pulmonary aerosol deposition during mechanical ventilation.

Increased delivery of aerosol to a model lung (attached to a mechanical ventilator) has been demonstrated with an ultrasonic nebulizer as compared to a jet nebulizer. This study examined whether the increased aerosol deposition with an ultrasonic nebulizer could also be demonstrated in vivo. Seven patients (6 male and 1 female) were studied during mechanical ventilalion (Siemens Servo 900C, Middlesex, UK) after open heart surgery. Two studies were performed in each patient. In the first study, aerosol was delivered via a Siemens Servo 945 nebulizer system (high setting) driving a System 22 Acorn jet nebulizer (Medic-Aid, Sussex, UK) containing 3 mL (99m)technetium-labelled human serum albumin (99mTc-HSA) (50 microg; activity 74 MBq). In the second study, a DP100 ultrasonic nebulizer (DP Medical, Meylan, France) containing 12 mL 99mTc-HSA (50 microg; activity 185 MBq) was used. Pulmonary deposition was quantified using a gamma camera. The humidification of the circuit and the ventilator settings were kept constant according to the patient's clinical requirements. The total lung aerosol deposition (mean+/-SD), as a percentage of initial nebulizer activity, was greater using the ultrasonic nebulizer than using the jet nebulizer (53+/-1.4 vs 2.3+/-0.9%; p<0.002). The ultrasonic nebulizer was also associated with a reduction in the time required to complete nebulization (9 vs 21 min, respectively) (p<0.0001). Use of the DP100 ultrasonic nebulizer more than doubled lung deposition compared with the System 22 jet nebulizers in mechanically-ventilated patients. Their efficiency, speed of drug delivery, and compatibility with mechanical ventilator circuits make ultrasonic nebulizers potentially attractive for use during mechanical ventilation.

Administration, Inhalation↗

PubMed1997

Effect of nebulizer type and antibiotic concentration on device performance.

We compared the performance of selected ultrasonic and jet nebulizers when aerosolizing several antibiotic formulations to determine optimum combinations for delivery of a respirable antibiotic aerosol. Three ultrasonic devices were tested: the UltraNeb 99/100, the UltraAIR and the Aerosonic. The reusable jet nebulizers were the Dura ProNeb, Pari-LL and the Sidestream. The six disposable jet nebulizers were Marquest Acorn II, Hudson T Updraft II, Baxter MistyNeb, Pari-LC, Pari IS-2, and a disposable Sidestream. Each jet was tested with four compressors: a DeVilbiss AP-50, a Pulmo-Aide, a DuraNeb and a PariMaster. All nebulizing systems were initially tested with normal saline. From the initial data, six jet nebulizers and one ultrasonic device were tested with varying concentrations of tobramycin, gentamicin, ceftazidime, ciprofloxacin and colistin. Output was assessed by measuring volume (milliliters per minute), and amount of drug (milligrams per minute) nebulized. We then measured mean particle size of the antibiotic aerosol with seven jet nebulizers and two different compressors, Pulmo-Aide and PariMaster, and two ultrasonic devices. The rate of nebulization of saline and antibiotic solutions (milliliters per minute) was greater with the ultrasonic device(s) than all jet nebulizer systems tested. Increasing the reservoir antibiotic concentration increased the drug output (milligrams per minute) with the jet nebulizers to a maximum, followed by decreasing output. When antibiotic concentrations were increased the output decreased more precipitously with the ultrasonic devices than with the jet nebulizers. At the highest antibiotic concentrations tested, the ultrasonic devices had the lowest output. Particle size distribution was most dependent on the specific jet device, with particle size distribution less affected by a specific antibiotic or its concentration. Higher reservoir concentrations can be utilized for increasing output of respirable antibiotic aerosols by jet nebulizers. We conclude that antibiotic output is dependent upon both the nebulizing system and the reservoir concentration of antibiotic.

Aminoglycosides↗