Inhalation of single vs multiple metered-dose bronchodilator actuations from reservoir devices. An in vitro study

Differences in inhalation technique with reservoir or spacer devices may affect metered-dose inhaler (MDI) dose availability to a patient. PURPOSE: This study examined the effect of single vs multiple actuations of an MDI into reservoir devices on dose delivery of albuterol, with three clinically available reservoir brands. METHODS: An in vitro lung model simulated inspiration from the MDI reservoir system. Albuterol (Proventil; Schering) was delivered by MDI, with the Monaghan Aerochamber, the Diemolding Healthcare Division (DHD) aerosol cloud enhancer (ACE), and the Schering InspirEase, using standardized volumes and inspiratory flows of 30 L min(-1). The MDI was actuated into each brand of reservoir 1, 2, or 3 times in rapid succession, followed by a single inhalation. Aerosol dose at the reservoir mouthpiece was captured on a cotton filter, dissolved in ethanol, and measured with a spectrophotometer at 278 nm. RESULTS: For all three brands of reservoir, less accumulated dose of drug is delivered with multiple actuations than with multiple single actuations each followed by inhalation. The total dose in milligrams increased significantly with two multiple actuations compared with one actuation in the Aerochamber and ACE (p<0.01), but not in the InspirEase (p>0.05). The Aerochamber, ACE, and InspirEase delivered a mean total dose (SD) of 0.0264 mg (0.012), 0.0271 mg (0.007), and 0.0136 mg (0.006), respectively, with one actuation compared to 0.0485 mg (0.011), 0.0453 mg (0.013), and 0.0218 mg (0.009) with two multiple actuations. The increase in total dose with three multiple actuations was not significant compared to two actuations for any of the brands tested (p>0.05). Although total dose increased with multiple actuations, a decline in efficiency was seen with two and three multiple actuations, compared to single actuation. The dose delivered per actuation decreased for the Aerochamber, ACE, and InspirEase from 0.0264 mg (0.012), 0.0271 mg (0.007), and 0.0136 mg (0.006) with one actuation, to 0.0243 mg (0.006), 0.0226 mg (0.006), and 0.0109 mg (0.005), respectively, with two multiple actuations, for losses of 8.0%, 16.6%, and 19.9% in dose per actuation for each brand. A further decline in delivery per actuation to 0.0164 mg (0.001), 0.0184 mg (0.004), and 0.0097 mg (0.005) for the 3 brands, respectively, was found with 3 multiple actuations before inhalation. This was a loss of 37.9%, 32.1%, and 28.7% of the dose per single actuation in each brand. There was no significant difference between the Aerochamber and the ACE in dose availability with 1, 2, or 3 actuations, but both of these brands provided significantly more drug than the InspirEase. CONCLUSION: Maximal aerosol bronchodilator from an MDI reservoir was given by single actuations each followed by a breath. Two rapid actuations followed by a breath will give a significant accumulation of dose with some loss when compared to two single actuations each followed by inhalation. Three multiple actuations led to a loss of approximately one third of the drug dose obtainable with three single actuations each followed by inhalation, for all three brands.     

The detection of cytochrome P450 2E1 and its catalytic activity in rat testis

The aim of this study was to compare the efficacy of 100 micrograms of salbutamol inhaled from a new metered-dose powder inhaler (MDPI, Leiras Taifun, Finland) with that of a same dose of salbutamol inhaled from a conventional pressurized metered-dose inhaler with a large volume spacer (pMDI + S) in protecting against methacholine (Mch) induced bronchoconstriction. This was a 3 day, randomized, cross-over, partly blinded, placebo-controlled multicentre study where the pMDI + S was used as an open control. Twenty-six asthmatic outpatients with a baseline FEV1 > or = 60% of predicted and with bronchial hyperreactivity (PD20 FEV1 < or = 890 micrograms of Mch) were studied. On each study day the patients underwent an Mch provocation 30 min after inhaling placebo from the MDPI or a dose of 100 micrograms of salbutamol from the MDPI and from the pMDI + S. PD20 FEV1 and dose-response slope [DRS; maximal change in FEV1 (%)/dose of Mch (mumol)] were used to evaluate efficacy. The median values of PD20 FEV1 were 250, 622 and 1737 micrograms after placebo MDPI, salbutamol pMDI + S and salbutamol MDPI, respectively. The corresponding DRS values were -11.0%, -4.5% and -2.0% mumol-1. With both parameters, all differences were statistically significant (P < 0.05). In conclusion, 100 micrograms of salbutamol inhaled from Leiras Taifun MDPI offers better protection against Mch-induced bronchoconstriction than 100 micrograms of salbutamol from a pMDI connected to a large volume spacer device.     

Duration of action of formoterol and salbutamol dry-powder inhalation in prevention of exercise-induced asthma in children

The aim of this study was to evaluate the effect and tolerability of formoterol 12 micrograms on exercise-induced asthma in children for 12 h as compared to the effect of salbutamol 400 micrograms and placebo. The drugs were inhaled as dry powder from a flow-dependent metered-dose inhaler (DP-MDI). Sixteen asthmatic children took part in a double-blind placebo-controlled within-patient single-centre trial. On each study day the patients were given one of the drugs or placebo in random order, and standardized exercise tests were performed after 3 and 12 h. At a pretrial test the children had demonstrated a median maximum percentage fall of 38% (range 22-79%) in forced expiratory volume in 1 s after exercise challenge. Formoterol showed a median percentage protection of 77% and 70% at 3 and 12 h postexercise, respectively, as compared to 46% and 13% with salbutamol. No side-effects were observed. Formoterol 12 micrograms administered as dry powder offers significantly better protection against exercise-induced asthma after 3 and 12 h as compared to salbutamol 400 micrograms and placebo.     

Cervical ripening

Electrostatic charge in plastic spacer devices has been shown in vitro to reduce delivery of asthma medications intended for inhalation, but the effect of static charge on in vivo drug deposition is unknown. A six-way randomized crossover study was conducted in 10 mild asthmatic patients. Two plastic spacers (Nebuhaler and Volumatic) and one metal spacer (Nebuchamber) were tested. The spacers were used either "primed" or "unprimed". Priming was performed by firing 20 doses of placebo aerosol into a new spacer, hence coating the inner surface with surfactant and minimizing static charge. Unprimed spacers were new and were not treated. Pressurized aerosol canisters delivering budesonide (200 microg Pulmicort) were radiolabelled with the radionuclide 99mTc and lung deposition was measured by gamma scintigraphy. The radiolabel was shown to be a valid marker for the drug substance prior to the clinical phase of the study. Priming significantly increased mean whole lung deposition following inhalation from plastic spacers (Nebuhaler primed 37.7% and unprimed 26.7%, p=0.01; Volumatic primed 32.0% and unprimed 22.1%, p=0.02). Priming had no effect on the mean whole lung deposition following inhalation from the Nebuchamber (primed 33.5% and unprimed 32.9%). Lung deposition in vivo from plastic spacer devices will vary according to the electrostatic charge on the spacer walls. Priming reduces retention of drug on plastic spacer devices and increases lung deposition. Metal spacers are not susceptible to static charge, which should result in more predictable lung deposition.     

Automatic actuation of a dry powder inhaler into a nonelectrostatic spacer

This article describes a new "automatic spacer" device, which has been developed to improve the delivery of inhaled medication to young children. In the device, a dry powder inhaler (DPI) is mechanically actuated into a nonelectrostatic spacer, producing an aerosol cloud of fine drug particles (aerodynamic diameter, < 4.7 microm) with a long half-life. The new device combines the principal advantages of the conventional spacer and the DPI. It has the potential to provide a high ratio between lung dose and pharyngeal dose, without need for coordination or forced inhalation, and it avoids exposure of the patient to the additives and propellants used in pressurized metered dose inhalers. Studies with the prototype device show a high yield of fine drug particles in the aerosol (mass median aerodynamic diameter, 2.8 microm), a high repeatability of drug delivery owing to the mechanical nature of the actuation (relative standard deviation, 12%), and a prolonged residence time of the fine particle aerosol (half-life of the fallout of the fine particles, 82 s). These features should prove advantageous in the treatment of young children with inhaled medication.     

Is asthma treatment affordable in developing countries?

BACKGROUND: A study was undertaken to assess whether the therapeutic aspects of published international asthma management guidelines are practically applicable in developing countries. METHODS: Questionnaires were sent to expatriate doctors working in developing countries. RESULTS: Forty one replies were received from 24 countries in Africa and Asia. Oral salbutamol was prescribed "usually" or "often" by 35 of the 41 respondents, theophyllines by 30, inhaled bronchodilators by 12, inhaled steroids by two, and cromoglycate by two. Theophyllines were locally available in all 41 cases, oral salbutamol in 40, inhaled bronchodilators in 34, and inhaled steroids (usually beclomethasone 50 micrograms) in only 15. Where they were available, the median (range) coat of a beclomethasone 50 micrograms inhaler was 20% (6.8-100%) of average local monthly income, salbutamol inhaler 13% (3.3-250%), 90 salbutamol 4 mg tablets 3.8% (0.8-75%), and 90 aminophylline 100 mg tablets 4.5% (0.5-70%). If they were available locally at a cheaper price, 34 (83%) respondents would prescribe more inhaled steroids and 37 (90%) would prescribe more inhaled bronchodilators. CONCLUSIONS: Many asthma patients in developing countries are not receiving adequate treatment because the required drugs are not available in their area or are prohibitively expensive.     

Effects of salbutamol delivery from a metered dose inhaler versus jet nebulizer on dynamic lung mechanics in very preterm infants with chronic lung disease

Treatment of chronic lung disease of prematurity requires effective aerosol delivery of different therapeutic agents. Aerosols can be generated by a metered dose inhaler (MDI) or a jet nebulizer. An MDI combined with a spacer device is easier to use and avoids undesirable effects noted in conjunction with jet nebulization. We compared the clinical effectiveness of 200 micrograms (2 puffs) salbutamol delivered from an MDI in conjunction with a valved spacer device (Aerochamber), and 600 micrograms given via jet nebulizer (PariBaby) on 2 consecutive days, the order being randomized. Thirteen spontaneously breathing very preterm infants [mean (SD) gestational age 27.2 (1.8) weeks; birth weight 0.90 (0.34) kg] were studied at a corrected age of 37 (2.3) weeks. Mean (SD) study weight was 1.83 (0.38) kg. Dynamic lung compliance and resistance were determined from measurements of flows, volumes, and transpulmonary pressures, using a pneumotachometer and a small esophageal microtransducer catheter before and 20 min after salbutamol application. Baseline values before salbutamol administration were similar on both occasions: the mean (SD) compliance was 7.7 (3.0) mL.kPa-1.kg-1 pre-MDI plus-spacer and 8.4 (3.1) pre-jet nebulizer; the resistance was 10.4 (4.0) kPa.L-1.s pre-MDI plus-spacer and 9.7 (3.4) pre-jet nebulizer. Following salbutamol, compliance did not change significantly with either MDI plus spacer or jet nebulizer. Resistance fall significantly with MDI plus spacer (mean -2.2; 99.9% CI -0.35, -4.35) and jet nebulizer (-2.4; 99% CI -0.39, -4.42). We conclude that even in small preterm infants 200 micrograms salbutamol via MDI plus spacer improves dynamic resistance as effectively as 600 micrograms via jet nebulizer and may therefore be a preferable mode of aarosol administration.     

Dose equivalence and bronchoprotective effects of salmeterol and salbutamol in asthma

BACKGROUND: Salbutamol is the most widely prescribed short acting beta 2 agonist and salmeterol is the first long acting inhaled beta 2 agonist. The dose equivalence of salmeterol and salbutamol is disputed. Estimates of weight-for-weight dose ratio have ranged from 1:2 to 1:16. A study was undertaken to clarify the true dose ratio. METHODS: The bronchoprotection afforded against repeated methacholine challenge by inhaled salmeterol 25 micrograms and 100 micrograms and salbutamol 100 micrograms and 400 micrograms was compared in a randomised, double blind, placebo controlled, crossover trial. Subjects were 16 stable asthmatics with a baseline forced expiratory volume in one second (FEV1) of > or = 65% predicted, screening concentration provoking a fall in FEV1 of 20% (PC20FEV1) of < or = 8mg/ml, and a shift in PC20FEV1 of more than two doubling concentration steps following inhalation of salbutamol 400 micrograms. On five separate occasions subjects underwent methacholine challenge before and 30 and 120 minutes after drug administration. PD20FEV1 was calculated for each challenge. FEV1 at 90 minutes after drug administration was also recorded. RESULTS: Bronchoprotection afforded by salmeterol was increased at 120 minutes compared with 30 minutes and protection by salbutamol was decreased. Protection by both doses of salmeterol was similar to salbutamol 100 micrograms at 30 minutes but significantly greater at 120 minutes. FEV1 at 90 minutes was significantly greater after salmeterol 100 micrograms than after placebo, but there were no other significant differences between treatments. Maximal observed protection was equivalent for salmeterol 100 micrograms and salbutamol 400 micrograms. CONCLUSIONS: The data are compatible with a weight-for-weight dose ratio for salmeterol:salbutamol of < or = 1:4.     

Single centre open study to compare patient recording of PRN salbutamol use on a daily diary card with actual use as recorded by the MDI compliance monitor

The aim of this study was to assess the patients' use of inhaled short acting bronchodilators as rescue therapy during a 4-week study period. In this study an electronic metered-dose inhaler compliance monitor (MDI-CM) was used to measure the time and date of actuations of the device and this information was then compared with the patients' self reporting diary card (DC). Salbutamol canisters were used in the compliance monitor. The study was approved by the local ethics committee, and written informed consent was obtained from all patients. Patients aged 18 years and over who were either receiving, or in the investigators opinion required, inhaled salbutamol on a PRN basis were enrolled for a 4-week monitoring phase during which all rescue salbutamol used was obtained from the MDI-CM. Patients were recording their use of salbutamol in the DC each morning and evening. There was a 2-week follow-up period following completion of the monitoring phase or withdrawal from the study. Forty-four patients were enrolled and 35 patients completed the study. The mean age (range) was 43 (20-76) years and mean FEV1 2.32 (0.7-4.0) 1, with male:female ratio of 19:25. Comparison of MDI-CM and DC recordings showed patients fell into three categories: (1) patients who used rescue salbutamol appropriately and whose MDI-CM and DC recordings matched closely; (2) patients who used rescue salbutamol for acute relief but whose MDI-CM and DC recordings did not correlate and (3) patients whose use of rescue salbutamol was inappropriate or erratic according to the MDI-CM but whose DC indicated good compliance. This category of patients include those who 'dumped' all their salbutamol before attending clinic appointments. There was no significant difference in the demographic details or the severity of disease in the three groups. Recorded use of 'rescue' bronchodilator is frequently used as an indicator of efficacy for new anti-asthma therapies. This study comparing electronic data monitoring and remembered rescue salbutamol highlights the potential errors that can occur without accurate recording systems.     

Estimating the cost of lost productivity in dyspepsia

In a two-day, randomised, double-blind, double-dummy, cross-over multicenter study, the bronchodilating effect of 100 micrograms of salbutamol (CAS 18559-94-9) inhaled from a new metered dose powder inhaler (MDPI; Taifun) was compared with that of an identical dose of salbutamol inhaled from a conventional pressurised metered dose inhaler connected to a spacer (pMDI + S). Thirty-six non-smoking, adult asthmatic outpatients with a baseline forced expiratory volume in 1 s (FEV1) between 35 and 70% of the predicted value participated in the study. After inhalation of the study medication pulmonary function, FEV1 and airway resistance (R(aw)), blood pressure (BP), and heart rate (HR) were measured up to 6 h. Area under the FEV1 vs. time curve (AUCFEV1) was used as the primary efficacy parameter, and the 90% confidence intervals (CI) were used to judge clinical equivalence. Other efficacy parameters were used in supportive analyses as secondary parameters. Both treatments produced a clear improvement in pulmonary function. The mean +/- SD AUCFEV1 were 893 +/- 281 and 889 +/- 2761.min after MDPI and pMDI + S, respectively. The 90% CI for the relative efficacy of the MDPI is from 98 to 103% of that of the pMDI + S. Also the other efficacy parameters gave similar results without significant differences: the mean +/- SD values of percent increase in FEV1 were 47.2 +/- 19.3 and 44.7 +/- 20.8, the maximum absolute value of FEV1 were 2.87 +/- 0.77 and 2.86 +/- 0.77, the maximum percent decrease in R(aw) 53.2 +/- 20.5 and 55.0 +/- 19.1, and the minimum absolute value of R(aw) 0.27 +/- 0.11 and 0.30 +/- 0.12 kPa.s.l-1 for the MDPI and pMDI + S, respectively. The salbutamol doses had no significant effect on BP or HR, and were equally well tolerated. Furthermore, 57.5% of the patients preferred the MDPI, 35% the pMDI + S, and 7.5% considered that there was no difference between the devices. In conclusion, this study demonstrates that the new MDPI is as effective and safe a device as a conventional pMDI connected to a spacer in administering inhaled salbutamol for asthmatic patients. Further, most patients considered the MDPI easier to handle, and preferred it over the pMDI + S.     

Aerosol therapy

Aerosol therapy plays a major role in the diagnosis and treatment of various lung diseases. The aim of inhalation therapy is to deposit a reproducible and adequate dose of a specific drug to the airways, in order to achieve a high, local, clinical effect while avoiding serious systemic side effects. To achieve this goal, it is therefore important to have an efficient inhalation device to deliver different medications. However, the currently available therapeutic inhalation devices (nebuliser, pressurised metered-dose inhaler and dry powder inhaler) are not very efficient in aerosol delivery and have several disadvantages. Inhalation devices can be assessed by in vitro studies, filter studies and radiolabelled deposition studies. Several radiolabelled deposition studies have shown that nebulisers and pressurised metered-dose inhalers are not very efficient in aerosol delivery. In children, before 1997, only 0.5% to 15% of the total nebulised or actuated dose from a nebuliser or pressurised metered-dose inhaler actually reached the lungs. These numbers were somewhat improved in adults, 30% of the total nebulised or actuated dose reaching the airways. Aerosol therapy with dry powder inhalers was the most efficient before 1997, 30% of the total dose being deposited in the lungs of adults and children. In 1997, new developments in pressurised metered-dose inhalers much improved their efficiency in aerosol delivery. Lung deposition can be increased by up to 60% with use of a non-electrostatic holding chamber and/or a pressurised metered-dose inhaler with a hydrofluoroalkane propellant possessing superior aerosol characteristics. Several studies comparing the clinical efficiency of different inhalation devices have shown that the choice of an optimal inhalation device is crucial. In addition to the aerosol characteristics, ventilation parameters and airway morphology have an important bearing on deposition patterns. These parameters may be greatly influenced by the patient's acceptance of a specific inhalation device and therefore determine the choice of the device used. It is important for the clinical impact to develop more efficient inhalation devices, which need to be assessed for use in different age groups. These devices should be cheap, easy to use, portable, usable with all medications and environmentally safe.     

Respiratory response to salbutamol (albuterol) in ventilator-dependent infants with chronic lung disease: pressurized aerosol delivery versus intravenous injection

OBJECTIVE: To compare the effects of intravenously injected with inhaled salbutamol in ventilator dependent infants with chronic lung disease (CLD). DESIGN: Prospective randomized study which each patient served as his/her own control. SETTING: Multidisciplinary neonatal and pediatric ICU. PATIENTS: 8 ventilator dependent premature infants with CLD. INTERVENTIONS: Salbutamol, 10 micrograms/kg was given intravenously, and 10-19 h later, twice 100 micrograms as pressurized aerosol, or vice versa, sequence randomized. The pressurized aerosol was delivered by a metered dose inhaler into a newly developed aerosol holding chamber, integrated into the inspiratory limb of the patient circuit. Respiratory system mechanics were assessed by the single breath occlusion method before and 10 and 60 min after drug administration. MEASUREMENTS AND RESULTS: Compliance improved significantly after intravenous injection (0.48 +/- 0.18 to 0.67 +/- 0.16, p < 0.01 and 0.59 +/- 0.23 ml/cmH2O/kg, NS, (mean +/- 1 SD) and after inhalation (0.46 +/- 0.19 to 0.64 +/- 0.32, p < 0.01 and 0.56 +/- 0.31 ml/cmH2O/kg, NS). Resistance decreased after iv. use (0.38 +/- 0.17 to 0.25 +/- 0.11, p < 0.001 and 0.25 +/- 0.10 cmH2O/ml/s, NS) and after inhalation (0.35 +/- 0.12 to 0.27 +/- 0.09, p < 0.01 and 0.28 +/- 0.12 cmH2O/ml/s, NS). Heart rate increased significantly after both routes of application, whereas mean arterial pressure, respirator settings, FIO2, transcutaneous SO2 and capillary PCO2 did not change. CONCLUSIONS: Inhaled and intravenous salbutamol improves pulmonary mechanics to the same extent with comparable side effects, and may therefore be used to facilitate weaning from respirators.     

Formoterol inhaled as dry powder or via pressurized metered-dose inhaler in a cumulative dose-response study

Formoterol administered by a dry-powder (DP) capsule inhaler was compared with a pressurized metered-dose inhaler (pMDI) with regard to bronchodilating and systemic effects. The study used a double-blind, crossover, double-dummy technique. Twelve patients with moderate reversible asthma in a stable phase were examined on two separate study days, and the inhalers were given in randomized order. After baseline measurements, increasing doses of formoterol were given at intervals of 75 min. FEV1 and heart rate and tremor measurements were repeated after each dose, and the doses were 12 + 12 + 24 + 48 micrograms, giving a total dose of 96 micrograms. The peak expiratory flow rate (PEFR) was recorded in the morning before the first dose, after the last dose, and then repeatedly at home until 19 h after the last dose. There was an equal increase in ventilatory capacity at each dose level, independent of inhaler device. Repeated PEFR measurements after the last dose did not reveal any differences in duration of effect. There was a slight but statistically significant increase in heart rate and tremor after the highest doses of the DP formulation compared to the pMDI. These systemic effects can probably be explained by the reduced oral deposition of the aerosol caused by using a spacer. This study indicates that the DP and pMDI formulations of formoterol are equipotent in bronchodilation.     

Coagulatory response after femoral instrumentation after severe trauma in sheep

Budesonide inhalation powder, available as Pulmicort Turbuhaler, is a corticosteroid with a high ratio of local to systemic effects that is administered to treat persistent asthma. The Turbuhaler achieves lung deposition approximately twice that of a metered-dose inhaler (MDI) with or without a spacer device. Budesonide inhalation powder has clinical efficacy equivalent to that of fluticasone and beclomethasone, but it has lower systemic bioavailability and fewer systemic side effects. As with other inhaled corticosteroids, dysphonia and oral candidiasis are the most frequent adverse effects, and systemic effects are infrequent. The initial starting dosage is 200 microg (1 puff) twice/day and may be increased to 800 microg twice/day in adults or 400 microg twice/day in children. Patients prefer the Turbuhaler to the MDI, Diskhaler, and Rotahaler because it is easier to use and more convenient to carry.     

Acute treatment-related diarrhea during postoperative adjuvant therapy for high-risk rectal carcinoma

STUDY OBJECTIVES: To examine the main therapeutic response patterns to high doses of salbutamol and to determine the factors that contribute to outcome in acute severe asthma. SETTING: The emergency department (ED) of a large, urban hospital with primary and referral care responsibilities. PATIENTS AND DESIGN: One hundred sixteen consecutive patients with acute exacerbations of asthma were enrolled in the trial, using a prospective sequential design. INTERVENTIONS: All patients were treated with salbutamol delivered with a metered-dose inhaler into a spacer device in four puffs (400 microg) at 10-min intervals. The protocol involved 3 h of this treatment (1,200 microg each 30 min). MEASURES AND RESULTS: A dose-response increase in pulmonary function was found, but only 70% improved sufficiently to be discharged. Of these, almost 70% required < or =2.4 mg of the drug within 1 h to reach the discharge threshold, whereas the remainder 30% need > or =3.6 mg. In 30% of subjects, salbutamol was ineffective. These patients were characterized by a more severe disease as judged by previous beta2-agonist use, larger duration of attack before ED visit, and a more severe obstruction at presentation. However, the most important predictors of outcome were peak expiratory flow rate (PEFR) as percent of predicted, PEFR as liters per minute, and PEFR variation over baseline value, all at 30 min. CONCLUSIONS: This study described two different therapeutic response patterns to salbutamol. Almost 70% of patients were sensitive to salbutamol (good response pattern), and in this group, 2.4 to 3.6 mg represents optimal treatment. In the remainder 30% of patients (poor response pattern), salbutamol in high doses had little effect. However, the outcome was not determined by the intensity of the initial symptoms or by the value of the presenting PEFR, but rather by the early (30 min) short-term response to treatment.     

Bronchodilator response to salbutamol after spontaneous recovery from nonspecific bronchial provocation tests in asthma

Assessment of airway responsiveness by bronchoprovocation and bronchodilatation tests is important in the diagnostic work-up protocol of bronchial asthma and it would be convenient to undertake both tests on the same occasion. However, it is not known whether this can be done accurately. Therefore, this study evaluated the effect of a prior bronchial provocation test on the bronchodilator response to salbutamol after spontaneous recovery of the forced expiratory volume in one second (FEV1) in a group of asthmatic subjects. On two separate occasions at the same time of day, concentration-response studies with inhaled histamine or methacholine, or a sham challenge with normal saline were carried out in a blinded, randomized manner. Changes in airway calibre were followed as FEV1 and agonist responsiveness expressed as the provocative concentration causing a 20% fall in FEV1 (PC20). After either spontaneous recovery or a fixed-duration wait of 45 min (when appropriate), the subjects received 2x100 microg of salbutamol from a metered dose inhaler with a spacer. The bronchodilator response to salbutamol was expressed as a percentage of initial FEV1 (deltaFEV1% init). Bronchial challenge with both agonists failed to alter significantly the airway response to salbutamol, with the deltaFEV1% init mean value (range) being 16.9% (9.0-31.9) and 17.5% (11.6-31.2) on the sham and histamine/methacholine challenge day respectively. It was shown that the degree of bronchodilatation achieved after salbutamol 200 microg is not affected by prior bronchoprovocation testing when enough time is allowed for the airways to recover spontaneously to baseline forced expiratory volume in one second. Thus evaluation of airway responsiveness by both bronchial provocation tests and bronchodilator testing can be assessed reliably within a few hours in asthmatic patients.     

Immunohistochemical demonstration of androgen receptors in human salivary glands

One hundred and eighty-one children with asthma were entered into a randomized, controlled, crossover study comparing sodium cromoglycate via a metered dose inhaler (MDI) and a breath-actuated inhaler (Autohaler). There were no significant differences in pulmonary function tests (FEV1, FVC, PFER), symptom scores and bronchodilator use between the two devices. However both patients' and clinicians' opinions of sodium cromoglycate effectiveness were significantly better (P < 0.01) for the Autohaler. Autohaler was also thought to be easier to use (P < 0.001) and better for co-ordination of actuation with inhalation (P < 0.001). The Autohaler is as efficacious as the metered dose inhaler used by good co-ordinators. It seems to be the significantly better device with respect to ease of use, actuation and co-ordination which may aid compliance.     

Urinary bacteriology in the elderly in the tropical zone: results of 5 years of activities at the CHU of Fann in Dakar

The distribution pattern of budesonide in the nasal passages and lungs was investigated in 10 healthy subjects after nasal inhalation. The subjects inhaled drug powder, radiolabelled with 99mTc, at maximum flow rate (46.3 +/- 6.8 l/min) and at 29.9 +/- 2.5 l/min via Turbuhaler. At both flows, the majority of the dose was deposited in the anterior part of the nasal cavity on a single, rather localized area, but some particles also penetrated more posteriorly into the main nasal passages and to the lungs. At maximum flow rate the nasal deposition was 65.2% (range 39.5-84.1%) and the lung deposition 4.7% (range 1.4-9.3%) of the metered dose, and at 30 l/min, the nasal deposition was 67.6% (range 49.7-81.6%) and the lung deposition was 4.2% (range 1.7-7.9%). A large fraction of the metered dose was deposited in the nasal adaptor of the inhaler during the administration (mean values 29 and 28%, for the two inhalation flows). Of the dose actually reaching the subject, 91 and 93% (mean values) was deposited in the nose. There were no statistically significant differences in distribution pattern between the two inhalation flows.     

Clinical trial of two inhalation techniques for pressurized aerosols

The clinical effects of a bronchodilator, terbutaline sulphate, were compared after administration in the beginning of the inhalation by means of a standard inhaler and administration by actuating 2 seconds before starting the inhalation by means of an inhaler furnished with a 32 X 100 mm tube. No differences could be seen in the parameters measured-forced vital capacity (FVC), 1-second forced expiratory volume (FEV1), forced mid-expiratory flow (FMF), and oscillatory resistance (Ros). The results indicate that when attaching a tube to the standard inhaler co-ordination of inhalation and actuation of the aerosol is not of vital importance.