Inhalation Maneuver Research Articles

Aerosol therapy: The special needs of young children

Efficient aerosol therapy in young children is a challenge. The aerosol administration method requires special features, because young children can not perform an inhalation manoeuvre, breath usually through the nose and may be distressed during the administration. The prescribing clinician should be aware of the advantages and disadvantages of the different inhalation devices available, in order to select the proper device for each individual patient. For maintenance asthma therapy in young children the pressurized metered dose inhaler (pMDI) combined with spacer is the first choice for delivering aerosols. A facemask can be attached if a child is unable to breath through the mouth. A small leak of the facemask can reduce the dose delivered dramatically, therefore a good seal is crucial. Lung deposition can be improved by using a pMDI with extra-fine particles. However, even if the most optimal device is chosen, cooperation during administration remains the most important determinant for efficient drug delivery. During crying the dose to the lungs is minimal. Optimal aerosol delivery to the lungs of young children can be achieved with a good facemask seal, good cooperation of the child, with quiet breathing and an aerosol with small particles.

Dose Delivery Characteristics of the AIR® Pulmonary Delivery System Over a Range of Inspiratory Flow Rates

The purpose of this study was to evaluate the in vitro and in vivo dose delivery characteristics of the AIR pulmonary delivery system over a range of flow rates. A 5-mg placebo powder of engineered particles with low densities (<0.4 g/cc) and large geometric diameters (>5 microm) was delivered via a simple, capsule based, passive dry powder inhaler. The emitted dose, geometric and aerodynamic particle size distributions (aPSDs) were obtained over a range of flow rates (15-60 LPM). The in vitro results demonstrated improved powder dispersion with increasing flow rate through the inhaler. The in vivo dose delivery characteristics were obtained by gamma scintigraphy. Twelve healthy subjects performed the following three inhalation maneuvers: (i) a targeted peak inspiratory flow rate (PIFR) of 20 +/- 10 LPM, (ii) a deep comfortable inhalation, and (iii) a deep forced inhalation. PIFR and inhaled volume were obtained during the inhalation of the dose using a spirometer. In vivo dose delivery was characterized by high and reproducible emitted doses (mean = 87%; inter and intra-subject CV = 5%) and high lung deposition (mean = 51% of the total dose), with low inter and intra-subject CVs (18% and 13%, respectively) across a range of PIFRs (12-86 LPM). Lung deposition of the total dose was shown not to be dependent on PIFR by analysis of variance across the range of inspiratory flow rates (p = 0.29). This was due to the competing effects of smaller aPSDs, increased extrathoracic deposition and higher emitted doses with increasing PIFR. Fully characterizing the effect of inspiratory flow rate requires analysis of the therapeutic response, as well as in vitro dose delivery and lung deposition.

Differences in COPD care among doctors who control the disease: General practitioner vs. pneumologist

To assess the role of doctors who patients report as responsible of their disease, in moderate-severe chronic obstructive pulmonary disease (COPD), describing characteristics of patients and treatments use according to each type of doctor, and relating it to the way of access to hospital at the time of an exacerbation. A systematic sample of 1:2 patients admitted for a COPD exacerbation during 1 year in four tertiary hospitals in the Barcelona area, Spain, was recruited. Information about health services was obtained by an administered questionnaire. A total of 346 patients were recruited: mean age 69 (+/-9) years, percent of predicted FEV(1) of 35 (+/-16)%, PO(2) of 64 (+/-13)mmHg. At the time of admission, 17% of patients reported being controlled by a general practitioner (GP) and 56% by a pneumologist whereas 21% reported its COPD not being under the regular control of any doctor. Patients not controlled by a pneumologist did not suffer from milder COPD than the remaining, but were less likely to receive pharmacological and non-pharmacological treatments and less likely to perform correctly the inhalation manoeuvres. During the course of the exacerbation 70% of patients reported a visit to a hospital emergency room department without a previous medical visit, this proportion being higher among those controlled by a pneumologist. Lack of control and variability in the patterns of care among patients controlled by different types of physicians are common in moderate-to-severe COPD patients admitted for a COPD exacerbation, despite the lack of differences in COPD severity. Medical control of COPD patients needs more investigation and a wider inclusion in international guidelines.

The Novolizer ®: overcoming inherent problems of dry powder inhalers

For most dry powder inhalers (DPIs) a defined minimal inspiratory flow must be achieved immediately after the start of the inspiration procedure, to avoid insufficient deposition in the lung and excessive drug deposition in the patient's mouth and/or oropharynx. The Novolizer ® (VIATRIS GmbH & Co. KG, Frankfurt, Germany) provides a combination of technical features that ensure that every inhalation manoeuvre is performed with adequate inspiratory and sufficient drug particles are delivered to the patient's lung. One of these technical features is an inspiratory flow rate threshold triggering feedback mechanisms to the patient which confirm that an adequate inspiratory flow rate (minimum 35–50 l/min) has been achieved. Correct inhalation manoeuvre is confirmed to the patient by optical, acoustic and taste feedback which is likely to improve patient compliance. The Novolizer ® also delivers a high-quality aerosol (high fine particle fraction representing the proportion of respirable particles), provides a refillable cartridge system, an accurate dose counter, a low intrinsic resistance, and enables reliable and consistent dose delivery. The Novolizer ® is at the cutting edge of inhalation technology and represents a major step forward in DPI design.

Patient Preference in the Choice of Dry Powder Inhalers

To investigate a group of patients' preferences among 3 dry powder inhalers--Accuhaler, Easyhaler, and Turbuhaler--and to analyze the features that were most important for motivating choices. The study enrolled 30 patients with stable asthma with a mean (SD) age of 40 (13) and who habitually used inhaled corticosteroids. The patients were shown in detail how to use each of the devices and were randomized to begin using them in different orders. After using each inhaler for a week, the patients assessed 9 different features on a scale of 0 to 10 with an independent observer. The patients were asked to put the inhalers in order of preference, and finally to demonstrate they could use them correctly. All patients correctly performed the inhalation maneuver at the beginning and the end of the study. The mean final scores out of 90 of the 9 features evaluated were 75 (13) for the Easyhaler, 67 (12) for the Accuhaler, and 65 (14) for the Turbuhaler. Differences were statistically significant between the first and the second device (P=0.02) and the first and the third (P=.001) but not between the Accuhaler and the Turbuhaler (P=.376). Mean rating scores were 8.6 (1.4) for the Easyhaler, 7.3 (1.9) for the Turbuhaler, and 7.1 (1.6) for the Accuhaler. The Easyhaler was the first choice for 53% of patients, the Turbuhaler for 27%, and the Accuhaler for 20%. The Easyhaler was rated the highest by the patients in the study. The scores were a long way from the maximum score, so research into developing an ideal inhaler must continue.

Comparative Study of Different Inhaler Devices in Asthmatic Children

The inhaler is an important drug delivery system in the treatment of asthma, but inhaler technique is often inadequate. We assessed technique in children diagnosed with asthma, comparing the performance of three devices. In a cross-sectional survey, 523 children (271 boys, 252 girls, ages 5 to 12 years; mean+/-SD 7.53+/-1.79 years) demonstrated inhalation technique according to Netherlands Asthma Foundation criteria during a first visit to a primary care clinic in Abha, Saudi Arabia. Patients used the device with which they were most familiar (either pMDI, Turbuhaler or Diskus). Two hundred children (38% of total population) used a pMDI, while 323 (62% of total population) used one of the dry powder inhalers 173 (58%) the Turbuhaler and 150 (47%) the Diskus. Only 49 children (25% of the total population) completed the assessment without making a mistake. The remaining 474 (75% of the total population) performed one or more manuevers poorly. Only 80 children who used an MDI (40% of those using the device) completed 50% or more of the maneuvers correctly compared with 111 (69% of those using the device) and 100 (67% of those using the device) of those using the Turbuhaler and Diskus, respectively (P=0.001 for comparison of MDI with dry powder inhalers). Children whose mothers had intermediate school or higher education performed better than those whose mothers had less education (P=0.001). The father's education had no bearing on performance with the inhaler. The inhaler technique of most asthmatic children is poor, but technique is better in children who use a dry powder compared a metered-dose inhaler. The level of the mother's education is positively associated with better inhalation technique in the child.

Pharmacodynamics and Pharmacokinetics of Inhaled Iloprost, Aerosolized by Three Different Devices, in Severe Pulmonary Hypertension

Inhalation of iloprost, a stable prostacyclin analog, is an effective therapy for pulmonary hypertension with few side effects. This approach may, however, be handicapped by limitations of currently available nebulization devices. We assessed whether the physical characterization of a device is sufficient to predict drug deposition and pharmacologic effects. We investigated the effects of a standardized iloprost aerosol dose (5 micro g; inhaled within approximately 10 min) in 12 patients with severe pulmonary hypertension in a crossover design employing three well-characterized nebulizers. The nebulizers use different techniques to increase efficiency and alveolar targeting (Ilo-Neb/Aerotrap [Nebu-Tec; Elsenfeld, Germany], Ventstream [MedicAid; Bognor Regis, UK], and HaloLite [Profile Therapeutics; Bognor Regis, UK]). Measurements were performed using a Swan-Ganz catheter and determination of arterial iloprost plasma levels. During inhalation of iloprost, the pulmonary vascular resistance decreased substantially (baseline, approximately 1,250 dyne.s.cm(-5); decrease, - 35.5 to - 38.0%) and pulmonary artery pressure decreased substantially (baseline, approximately 58 mm Hg; decline, - 18.4 to -21.8%), whereas the systemic arterial pressure was largely unaffected. Cardiac output and mixed venous and arterial oxygen saturation displayed a marked increase. The pharmacodynamic profiles with the three devices were superimposable. Moreover, rapid entry of iloprost into the systemic circulation was noted, peaking immediately after termination of the inhalation maneuver, with very similar maximum serum concentrations (158 pg/mL, 155 pg/mL, and 157 pg/mL), and half-lives of serum levels (6.5 min, 9.4 min, and 7.7 min) for the three nebulizers, respectively. Interestingly, the "half-life" of the pharmacodynamic effects in the pulmonary vasculature (eg, decrease in pulmonary vascular resistance, ranging between 21 and 25 min) clearly outlasted this serum level-based pharmacokinetic half-life. A standardized dose of aerosolized iloprost delivered by different nebulizer types induces comparable pharmacodynamic and pharmacokinetic responses. Pulmonary vasodilation, persisting after disappearance of the drug from the systemic circulation, supports the hypothesis that local drug deposition largely contributes to the preferential pulmonary vasodilation in response to inhaled iloprost.

Effect of Humidity on Constant Output and Breath Enhanced Nebulizer Designs When Tested in the EN 13544-1 EC Standard

Aqueous aerosols produced by nebulizers used in clinical situations can rapidly change size as the patient inhales. This is caused by air with a relative humidity (RH) lower than inside the nebulizer being entrained and mixed with nebulized aerosol during the inhalation maneuver. A way to assess the change in size is to measure the aerosol in a test method that reflects the clinical situation. The EC standard, EN 13544-1, offers a first step towards this assessment. In this paper we have tested two nebulizer designs, one conventional constant output nebulizer and one breath-enhanced nebulizer, using the proposed standard in order to assess the effect of the relative humidity of entrained ambient air on nebulized aerosol size properties. The results indicate that aerosol size from the conventional nebulizer is greatly affected by the RH of the entrained air, while the breath-enhanced nebulizer is not affected. The results agree with theoretical expectations of how the entrained air interacts with nebulized...

The inhalation manager: a new computer-based device to assess inhalation technique and drug delivery to the patient.

The rational choice of an inhalation device is a cornerstone in the effective management of asthma and COPD. In this publication, we describe the development of a new system, the Inhalation Manager, which, for the first time, offers the possibility to assess the entire inhalation maneuver of patients using original devices under everyday conditions. So far the Inhalation Manager allows the measurement of inspiratory maneuvers of patients through placebo inhalation devices of the most common breath-actuated CFC-free inhalers in the market for the three main glucocorticosteroids Budesonide [Turbohaler (TH), dry powder inhaler (DPI)], Beclomethasone dipropionate [Autohaler (AH), breath-actuated pressurized metered dose inhaler (pMDI)], and Fluticasone propionate [Diskus (DI), DPI] by means of a pneumotachometer. In addition, it allows allocation of the individual maneuver to the expected drug delivery values (mass output and particle size distribution) of these three devices. In a field trial, the inhalation technique of 628 (TH), 794 (AH), and 795 (DI) patients, respectively, was tested in 72 pulmonologist practices with the Inhalation Manager. For patients in the 18-59-year-old group, the Inhalation Manager detected the following percentages needing improvement: 1.5% for the Autohaler device, 16.7% for the Diskus, and 38.9% for the Turbohaler. In the 60-99-year-old group, percentages needing improvement were 1.5%, 31.5%, and 66.1% for the Autohaler, Diskus, and Turbohaler, respectively. Therefore, the Inhalation Manager could become an essential tool in asthma management by finding the most suitable inhaler for an individual patient and by training the optimal inhalation technique.

Increased neutrophil mediator release in patients with pulmonary hypertension--suppression by inhaled iloprost.

Polymorphonuclear neutrophils (PMN) have been implicated in various vascular inflammatory processes. We isolated PMN from venous blood samples of 10 patients with severe primary pulmonary arterial hypertension (PPH), 7 patients with pulmonary hypertension secondary to chronic thromboembolism (CTEPH), and 12 healthy controls. When stimulated with the calcium-ionophore A23187, platelet activating factor (PAF) or the microbial agent n-formyl-Methionyl-Leucyl-Phenylalanine (fMLP), significantly increased release of elastase and superoxide anion was noted in both groups with pulmonary hypertension. Moreover, the neutrophils of CTEPH patients responded with an enhanced liberation of leukotriene (LT) B(4) and 5-hydroxyeicosatetraenoic acid (5-HETE). Inhalation of aerosolized iloprost (5 microg) caused a rapid decline in pulmonary vascular resistance, in both PPH and CTEPH. This hemodynamic response was paralleled by a significant suppression of ionophore- and ligand-induced elastase and superoxide release, as well as LTB(4) and 5-HETE formation. The neutrophil inhibitory effect of the inhalation maneuver was fully reproduced by in vitro incubation of neutrophils with 1-10 pg/ml iloprost for 2 hours. This is the first study to demonstrate that circulating neutrophils from patients with PPH and CTEPH possess an enhanced readiness to respond with inflammatory mediator generation to different stimulatory agents ex-vivo, and that PMN respiratory burst, elastase secretion and leukotriene generation are promptly reduced by an iloprost inhalation maneuver. Neutrophils might participate in the inflammatory processes in pulmonary arterial hypertension.

An exploration of the skills needed for inhalation therapy in schoolchildren with asthma in Taiwan

Clinical observation has shown that many asthma-affected children and their parents are not familiar with appropriate techniques for inhaler use. This may result in misuse, overdose, or diminished response of the administered therapeutic drugs, or may even result in unnecessary, repeated hospitalization. Inappropriate inhalation technique is hazardous to the safety of children with asthma and unnecessarily increases costs resulting from unnecessary rehospitalization. We designed a study to evaluate the skills needed for inhaler use among children with asthma in Taiwan. Schoolchildren with asthma, aged 8 to 13 years, were asked to demonstrate their inhalation technique. The inhalers used in this study were either metered-dose inhalers or dry-power inhalers. Assessment of the inhalation technique was made using a standardized inhaler checklist. A higher score indicates greater skill using the inhaler. This study surveyed 132 schoolchildren with asthma. Of those, only 23 (17.4%) asthmatic children who received inhalation therapy revealed good compliance with their medication regimens. No child was observed to have completed all inhaler techniques correctly. Those family members who participated in educational programs and who received instruction from health teams had higher scores for the inhaler checklist (P < 0.05). It was found that children who inhaled medication unaided had a better knowledge of asthma, and their drug inhalation technique was also more skillful (P < 0.03). By multiple regression analysis, we found that determinants of a child's skill at performing the inhalation maneuver included: number of asthma attacks within the preceding year, unaided application of inhaler therapy, older subject age, potential for subjects to receive instructions from parents regarding inhaler use, subjects reading related publications, and the family's degree of satisfaction with the physician's educational program. These variables contributed a total of 23% to variance in the subjects' inhalation technique. This study revealed that most asthmatic children being treated with inhaler medication do not use such devices appropriately. More aggressive asthma education is necessary in Taiwan.

SIMILAR EFFICACY FOLLOWING FOUR WEEKS TREATMENT OF ASTHMATICS WITH FORMOTEROL 12 μG B.D. DELIVERED BY TWO DIFFERENT DRY POWDER INHALERS: DIFFERENCES IN INHALER HANDLING

SUMMARYThis randomised, multicentre, parallel‐group study compared the clinical efficacy and ease of handling of two dry powder inhalers delivering the long‐acting β2‐agonist formoterol. After run‐in, 200 asthmatics on treatment with inhaled corticosteroids and still presenting with suboptimal asthma control were randomised to receive 12 μg formoterol twice daily via either the Aerolizer inhaler (Foradil® Aerolizer™) or the Turbuhaler inhaler (Oxis® Turbuhaler®) for four weeks. Study variables included the mean morning pre‐medication peak expiratory flow (PEF) during the last seven days of treatment and the correct inhaler handling according to inhaler‐specific checklists. The mean difference in the effect on morning pre‐medication PEF was 13.86 l/min in favour of formoterol via the Aerolizer inhaler (90% confidence interval 2.50, 25.21) in the intent‐to‐treat population. Eighty‐six per cent of the patients under treatment with formoterol via the Turbuhaler inhaler performed correctly all the essential inhalation manoeuvres, whereas 98% of those on the Aerolizer inhaler did so. These results strongly suggest similar clinical efficacy with twice daily treatment of formoterol 12 μg metered dose delivered either by the Aerolizer, or the Turbuhaler device. They also suggest that handling the Aerolizer is easier than that of the Turbuhaler.

Técnica de inhalación en los pacientes con enfermedades respiratorias crónicas

To determine how inhalers are used by patients with chronic respiratory diseases in the Community of Valencia (Spain) and to identify the factors associated with correct use. We carried out a prospective study of 554 patients (331 men, 223 women, mean age 50.5 +/- 21.5 years) who underwent spirometric testing (292 with bronchial asthma, 192 with COPD, 15 with bronchiectasis and 55 with other diagnoses). The patients were asked what type of inhaler they used. Pressurised canisters (PC) were used by 39.9%, inhalation chambers (IC) by 37.9% and dry powder inhalers (Turbuhalers) (DP) by 22.2%. They were also asked what instructions they had received; the inhalation techniques recommended by the Spanish Society of Pneumologists and Chest Surgeons (SEPAR) was reviewed step by step. a) Four hundred thirty-two patients (78%) reported having received instruction in how to use the inhaler; b) One hundred seventy-five (31.6%) used the correct technique: 25.3% using PC, 32.4% using IC and 41.5% using DP (p = 0.008); c) The most common errors were not holding the breath after inhaling in the case of PC users, not waiting 30 seconds between inhalation maneuvers and the lack of synchrony with inspiration among PC users; d) Use of correct inhalation technique was associated with prior instruction (rs = 0.249; p < 0.001) and younger age (rs = 0.92; p = 0.03). A high percentage of patients, particularly those using PC and those who received no instruction, use inhalers incorrectly in the Community of Valencia. We therefore recommend health education programs that target the main errors identified.

Validación de listas de comprobación de la técnica de inhalación para cartucho presurizado y Turbuhaler®

To determine the intra- and interobserver validity and reliability of two checklists for inhalation technique with a pressurized inhaler (PI) and the Turbuhaler. Transversal descriptive study performed at an urban health clinic in Gijón (Spain). Thirty-four patients, over 14 years of age but younger than 65, who used a PI and 35 who used a Turbuhaler were chosen randomly from among patients in our health clinic practice. The results obtained with each list by two observers were compared with those obtained by electronic monitors (test pattern). Each patient performed 3 inhalation maneuvers. Comparison with the test pattern showed that, between 35.2% and 47% of patients used the PI technique correctly, whereas 74.2% inhaled correctly using the Turbuhaler. The sensitivity of the PI checklist ranged from 62.5 to 91.6 and specificity ranged from 88.8 to 94.4. The sensitivity of the Turbuhaler checklist ranged from 50 to 76.9 specificity ranged from 66.6 to 88.8. Intra-observer agreement (Kappa index) was 0.62 to 0.74 for the PI checklist and between 0.77 and 0.81 for the Turbuhaler list. Interobserver agreement (Kappa index) was 0.68 to 0.81 for the PI list and 0.53 to 0.60 for the Turbuhaler list. The two checklists are valid instruments and offer good intra- and interobserver reliability, permitting easy identification of patients who perform the inhalation technique incorrectly.

Comparison of a New Multidose Powder Inhaler (Diskus©/Accuhaler©) and the Turbuhaler© Regarding Preference and Ease of Use

Many patients with asthma or chronic obstructive pulmonary disease (COPD) use their inhaler ineffectively. Several studies revealed that inhaler-specific design features contributed significantly to the failure rate, which clearly demonstrates the need for developing more “foolproof” inhalers. This study compared ease of use and patient preference of the Diskus®/Accuhaler® (DA) with the Turbuhaler® (TH). Fifty patients with asthma or COPD aged 15 years and older were included in a randomized, crossover comparison of DA with TH regarding patient preference and ease of use. All had to be naïve to DA and TH, but currently had to be using inhaled medication with another device. Inhalation technique was assessed using inhaler-specific checklists and patients had to state a preference for DA or TH regarding various aspects, as well as overall preference. With DA 46 patients (92%) made no errors regarding essential inhalation maneuvers, compared to 37 patients (74%) using TH (p = 0.023) This difference is exclusively caused by not loading the TH properly. When patients were asked which inhaler they would prefer, 17 wanted the DA, 25 the TH, and 8 did not state a preference. The difference was not significant. TH was favored over DA regarding factors related to size and the number of available dosages. The counting mechanism of the DA was preferred over the TH. It seems that patients have a clear, although not statistically significant, preference for TH, but with the DA fewer patients make crucial errors.

Evaluation of the long-term effectiveness of three instruction modes for inhaling medicines

Inhaled medication is important in the treatment of chronic obstructive pulmonary disease (COPD). In this paper a comparison of the long-term efficacy of three instruction-modes is presented. A total of 152 COPD-patients were randomized into one of four groups: Personal-, video-, group-instruction and a control group. Inhalation technique was assessed by means of checklists, on which essential inhalation manoeuvres were identified. Up to 9 months later, 148 patients returned for follow-up assessment. Prior to instruction 61% of patients in the control group had a perfect score on essential actions, compared to 62, 65 and 53% for those receiving group-, personal- and video-instruction respectively. At follow-up these percentages were 49, 97, 75 and 76%. For group-(35%) and video-instruction (24%) the increase from baseline was significant. Examining the different inhalers under investigation, it is striking, that only 24% of all patients with a Metered Dose Inhaler (MDI) performed all essential checklist items correctly, versus 96% for those using a Diskhaler. The fact that for the MDI this percentage improved to 90% post-instruction, shows that time spent on instruction, is time well spent. We conclude that group instruction seems superior to personal counselling, and equally effective or even better than video instruction. Personal instruction should not be dismissed and a combination with video instruction might prove to be effective as well.

Airway deposition and airway effects of antiasthma drugs delivered from metered-dose inhalers.

Many different metered-dose inhalation devices are becoming available for the treatment of airway diseases. Each of these inhalers differs in its delivery characteristics. An assessment of the efficacy of drug delivery by these inhalers is essential, in view of their therapeutic use. A review of the literature on the relationship between airway deposition and airway effects of drugs delivered from metered-dose inhalers is presented. Nebulizers or spacers are not discussed. The effect of an inhaler depends on the characteristics of the inhaler and the inhalation manoeuvre performed by the patient. This review focuses on the influence of inhaler characteristics on the airway deposition and airway effects. Data from several studies show that there is a significant relationship between the amount of drug deposited in the airways and the airway effects of the drug. Studies on the relationship between airway deposition and airway effect have been troubled by methodological problems, such as the absence of multiple dose comparisons and the difficulty in obtaining steep dose-response curves. The techniques for measuring airway deposition of inhaled drugs, namely the scintigraphic and the pharmacokinetic method, are discussed and compared. The appropriate use of these techniques can help to define and compare the drug delivery characteristics of different devices, thus enabling inhaled therapy to be optimized.

The impact of inspiratory effort on inspiratory flow through Turbuhaler in asthmatic patients

To investigate the impact of the inhalation effort on the peak inspiratory flow through Turbuhaler, 100 asthmatics having a wide range of asthma severity (baseline forced expiratory volume in one second 28-127% of predicted normal) were studied. Each patient inhaled through four modifications of empty Turbuhaler inhalers, using first a "deep" inhalation and then a "forceful and deep" inhalation manoeuvre. Peak inspiratory flow increased by an average of 20% using a "forceful and deep" as compared to a "deep" inhalation, with a markedly higher increase for the patients who had a low peak inspiratory flow using the deep inhalation. Virtually all patients (97-100%) attained a peak inspiratory flow > or = 40 L x min(-1) after a "forceful and deep" inhalation. This study demonstrates that instructing the patient to take a "forceful and deep" inhalation optimizes the use of Turbuhaler. Irrespective of asthma severity, the vast majority of patients could attain a sufficiently high peak inspiratory flow with a "forceful and deep" inhalation.

Conocimientos y destreza en el manejo del inhalador Turbuhaler® por parte del personal sanitario

The aim of this study was to evaluate health care workers' theoretical knowledge and skill in managing the dry powder Turbuhaler. We studied 118 individuals in three groups: 50 nurses, 34 medical residents and 34 staff physicians. Theoretical knowledge was evaluated by a questionnaire specifically designed for the purpose. Skill in managing the device was analyzed by evaluating a practical demonstration of the inhaling technique generally recommended, using a placebo inhaler. Six percent of staff physicians, 3% of the residents and 2% of the nurses answered the theoretical questionnaire correctly. Twenty-one percent of the staff physicians, 15% of the residents and 6% of the nurses inhaled correctly. However, when skill in managing the inhaler was evaluated against the maneuvers recommended by the manufacturer (which do not oblige exhaling before inhaling through the device and then holding the breath), there was significant improvement: 41% of the staff physicians, 23% of the residents, and 20% of the nurses inhaled correctly. We can conclude by saying that: a) our health care workers' general knowledge about how to handle the Turbuhaler device is deficient; b) the proportion of correct inhalation maneuvers observed doubles when these are assessed according to the manufacturer's recommendations, and c) health care workers should receive specific training in the inhalation techniques required for using the various devices usually prescribed.

Factors affecting total and "respirable" dose delivered by a salbutamol metered dose inhaler.

Many factors contribute to the high variability of doses delivered to the lungs of patients using metered dose inhalers (MDIs). Relatively little attention has been paid to the contribution to this variability of the way in which the MDI is handled before the inhalation manoeuvre. Instruction leaflets often recommend procedures at odds with those used for in vitro testing of the device. The standard protocol for in vitro assessment of salbutamol MDIs involves shaking the MDI vigorously for 30 seconds and wasting the first two actuations. Subsequent actuations are introduced into the testing device at five second intervals. Patient instructions do not include a recommendation to waste the first two actuations and recommend a delay of one minute between actuations. A series of experiments was performed to determine whether such differences might be important. The total and "respirable" doses delivered by a salbutamol MDI (Ventolin, Allen & Hanburys) under various conditions were assessed with a multistage liquid impinger. The quantity of drug deposited on each stage was measured by an ultraviolet spectrophotometric method. The effect on the delivered dose of not shaking the canister, not wasting the first two doses, waiting 30 seconds between actuations, and using multiple rapid actuations was assessed by comparing the results with those obtained using the standard in vitro testing protocol. Compared with a standard protocol, it was found that not shaking the MDI before use reduced the total and "respirable" dose by 25.5% and 35.7%, respectively. The dose delivered when actuating the MDI at 30 second intervals was no different from that when intervals was no different from that when intervals of five seconds were used. Two actuations separated by one second had no effect on the total dose but reduced the "respirable" dose by 15.8%, while four rapid actuations reduced the total and "respirable" doses by 8.2% and 18.2%, respectively. Storing the MDI stem down reduced the total and "respirable" dose delivered in the first actuation by 25.0% and 23.3% despite shaking the MDI before use. MDIs containing drug in suspension must be shaken before use to resuspend the drug contained in the MDI, but shaking does not alter the composition of the suspension in the metering chamber and hence the dose in the first actuation remains low. Very rapid actuations can reduce the dose delivered per actuation, but salbutamol MDIs can be actuated immediately after a 10 second breath holding pause without affecting the dose delivered.