Biomedical subjects

P N LeSouëf

Publications and source records attributed to P N LeSouëf.

At least 19 recordsLinked to original sources

PubMed2000

Parental factors affecting respiratory function during the first year of life.

In a prospective, longitudinal, population-based cohort study of familial and environmental influences on the development of wheezing respiratory illness in early childhood, we identified infant length, weight, gender, and exposure to maternal cigarette smoking as significant determinants of lung function during the first year of life. A cohort of 237 infants (106 females: 131 males) was evaluated, and 496 lung function measurements were made between the ages of 1-12 months. Respiratory function was assessed using the rapid thoracic compression technique to obtain maximum expiratory flow at functional residual capacity (V'maxFRC). Parental history of asthma and smoking habits during pregnancy were obtained by questionnaire. Data were analyzed using a longitudinal random effects model. Infants with a parental history of asthma and/or in utero passive smoke exposure were compared to a reference group of infants who had no parental history of asthma and in whom neither parent smoked pre- or postnatally. Boys were found to have a consistently lower V'maxFRC (-21.05 mL.s(-1)) throughout the first year of life in comparison to girls (P < 0.05). Maternal smoking during pregnancy was associated with a lower V'maxFRC in both genders in comparison to unexposed infants (P < 0.05). V'maxFRC was unaffected by parental history of asthma. Gender-specific normative equations for V'maxFRC throughout the first year of life were derived for the infant cohort as a whole and also for subgroups of infants, based on parental asthma and smoking history. We conclude that lung function during the first year of life differs between genders and is adversely affected by in utero passive tobacco smoke exposure. Gender-specific predictive equations for V'maxFRC should be used during infancy.

Cohort Studies↗

PubMed2000

High-percentage lung delivery in children from detergent-treated spacers.

Pressurized metered-dose inhalers attached to spacers are now the most common form of delivery of anti-asthma medication in children. However, no reliable data are available of how much drug reaches the lungs in children of different ages. This information is crucial, as it determines the efficacy of therapy. In this study, we present information on the amount of drug reaching the lungs in children from a pressurized metered-dose inhaler attached to a detergent-coated spacer. We studied 18 asthmatic children inhaling radiolabeled salbutamol through detergent treated spacers to minimize electrostatic charge on the spacer wall. Lung deposition was much higher than expected when using detergent-coated spacers. Mean (SD) lung deposition, expressed as a percentage of the total actuated dose (five actuations), was 16.4% (5.5) in younger children inhaling through a small volume spacer, and 28.2% (6.7) and 41.8% (3. 8) in older children inhaling with different breathing patterns through a large volume spacer. These findings have major implications for dosage regimens for inhaled anti-asthma medication in children. Lower doses may be sufficient for adequate drugs delivered through spacers treated for static to achieve a desired clinical response.

Administration, Inhalation↗

PubMed1999

Association of polymorphisms in the beta2-adrenoreceptor gene with higher levels of parasitic infection.

The diminishing incidence of parasitic infection in westernised societies has been suggested to result in an increased prevalance of asthma. Asthma is a polygenic disease and genome screens have shown that genes on chromosome 5q31-33 are strongly linked to the disease. The gene for the beta2-adrenoreceptor is located in this region and two polymorphisms have been identified that result in amino acid changes at positions 16 (ArgGly) and 27 (GlnGlu). To determine whether these polymorphisms influence asthma and parasitic infection, a genotype/phenotype study has been performed on a cohort of 126 children from Coche Island in Venezuela. There is a high incidence of asthma on the island and intestinal helminthiasis is endemic. Genotyping for both polymorphisms was carried out by using the polymerase chain reaction and allele-specific oligonucleotide hybridisation. Genotype frequencies in this cohort were consistent with other studies and both polymorphisms were in significant linkage disequilibrium. Individuals who were homozygous for Arg16 had significantly higher levels of specific IgE to Ascaris lumbricoides (P=0.002), significantly higher A. lumbricoides egg counts (P<0.001) and significantly larger wheal sizes following skin-prick testing with A. lumbricoides allergen (P=0.008). There was no association between either polymorphism and total serum IgE or asthma in this population. A combination of mast cell degranulation and the lung migratory phase of A. lumbricoides larvae may result in bronchoconstriction in infected individuals. These results suggest that the Gly 16 allele confers resistance to high levels of parasitic infection in this population. An alternative explanation for the association is that it may be the result of linkage disequilibrium with other genes in the chromosome 5q31-33 region.

Adolescent↗

PubMed1999

Inhalation therapy in asthma: nebulizer or pressurized metered-dose inhaler with holding chamber? In vivo comparison of lung deposition in children.

OBJECTIVE: To compare lung deposition from a nebulizer and a pressurized metered-dose inhaler (pMDI)/holding chamber to determine their efficiency in aerosol delivery to children. STUDY DESIGN: Children with stable asthma (n = 17) aged 2 to 9 years inhaled in random order radiolabeled salbutamol from a nebulizer and a pMDI through a nonstatic holding chamber. Body and lung deposition of radiolabeled salbutamol was assessed with a gamma camera. RESULTS: Mean (absolute dose) total lung deposition expressed as a percentage of the nebulized dose was 5.4% (108 microg) in younger children (<4 years) and 11.1% (222 microg) in older children (>4 years). Mean (absolute dose) total lung deposition expressed as a percentage of the metered dose was 5.4% (21.6 microg) in younger and 9.6% (38.4 microg) in older children. CONCLUSIONS: For the same age groups we have shown equivalent percentages of total lung deposition of radiolabeled salbutamol aerosolized by either a nebulizer or a pMDI/holding chamber. However, the delivery rate per minute and the total dose of salbutamol deposited were significantly higher for the nebulizer.

Albuterol↗

PubMed1999

Variability of aerosol delivery via spacer devices in young asthmatic children in daily life.

Pressurized metered dose inhalers (pMDI) are widely used together with spacers for the treatment of asthma in children. However, the variability of daily medication dose for pMDI/spacer combinations is not known. Electrostatic charge is a potential source of dose variability. Metal spacers have no static charge. This study assessed and compared within-subject variability of aerosol delivery of metal and plastic spacers. This was a randomized, crossover study in children with stable asthma aged 1-4 (group I, n=17) and 5-8 (group II, n=16) yrs. In both groups the amount of drug delivered to the mouth by a metal spacer (Nebuchamber) and one of two plastic (polycarbonate) spacers, i.e. Babyhaler in group I and Volumatic in group II was measured. The metal and plastic spacers were tested at home in a randomized order for 7 days each, using budesonide (200 microg b.i.d.). Aerosol was collected on a filter positioned between spacer and facemask or mouth. Budesonide on the filter was assessed by high performance liquid chromatography. The mean filter dose for each child (mean+/-SD) during the 7 days was expressed as a percentage of the nominal dose. Within-subject variability was expressed as coefficient of variation (CV). Mean filter dose in group I was 41.7+/-10.1% for Nebuchamber and 26.0+/-4.0% for Babyhaler (p<0.001). Mean filter dose in group II was 50.2+/-9.2% for Nebuchamber and 19.4+/-7.2% for Volumatic (p<0.001). Mean CV in group I was 34% for Nebuchamber and 37% for Babyhaler (p=0.44). Mean CV in group II was 23% for Nebuchamber and 34% for Volumatic (p=0.003). There was substantial within-subject dose variability in aerosol delivery in children using a pMDI/spacer at home. This variability was lower for the metal than for the plastic spacer in children 5-8 yrs of age. The dose delivered to the mouth was about two-fold higher for the metal than the plastic spacer independent of age.

Aerosols↗

PubMed1998

Parental attitudes toward infant pulmonary function testing.

Infant pulmonary function tests (PFTs) have proven increasingly popular and useful for clinical and research purposes. Informed consent requires accurate information on side effects. Our aim was to quantify minor side effects from a parental point of view by means of a questionnaire. The parents of 97 infants attending for PFTs were asked to complete a simple questionnaire. Eighty-one parents (84%) returned the questionnaire. Forty-one percent felt that their infants were not troubled by the process of administering the sedative chloral hydrate, whereas 55% suffered mild to moderate distress. In contrast, 94% of infants were not distressed by the actual PFTs. Similarly, 46% of parents were not distressed by the administration of sedative to their infant, with 49% expressing distress to a mild or moderate degree. Although 73% of parents were not distressed by watching their infants undergo the PFTs, 27% were to a mild to moderate degree. Seventy-three percent of infants were untroubled on waking. Seventy percent of infants had a good nights sleep after the PFTs. The vast majority of parents (94%) were happy to recommend that others allow their infants to undergo similar testing. We noted that most problems caused by infant PFTs relate to the administration of the sedative. Most infants awake from the tests not distressed and sleep normally the following night.

Attitude↗

PubMed1998

Bronchodilator responsiveness testing using raised volume forced expiration in recurrently wheezing infants.

We hypothesized that a new test of infant lung function, less affected by shifts in lung volume, might better detect bronchodilator effects. Using the raised volume forced expiration technique (RVFET), the effect of a bronchodilator on lung function was studied in 22 infants with a history of recurrent wheeze and five healthy infants. Forced expiratory volume in 0.75 s (FEV0.75), forced expiratory vital capacity (FVC), and forced expiratory flow at 75% of FVC (FEF75%) were measured by forcing expiration, using an inflatable jacket from a lung volume set by an inspiratory pressure of 20 cm H2O. A minimum of five measurements were made at baseline and following the administration of 500 microg of salbutamol from a metered dose inhaler via a small volume metal spacer. Changes in lung function in the group of 25 infants who received salbutamol were compared to seven infants who received placebo aerosol. No significant changes occurred in measures of lung function following salbutamol administration when compared to baseline or placebo despite a significant increase in heart rate. A shift in lung volume is unlikely the reason why infants do not demonstrate a change in forced expiration following bronchodilator administration.

Albuterol↗

PubMed1998

Atypical mycobacterial pulmonary disease and bronchial obstruction in HIV-negative children.

Atypical mycobacterial infection in HIV-negative children usually presents with cervical lymphadenopathy. We report on 10 children who are HIV-negative and who presented with pulmonary disease, in whom either culture-proven atypical mycobacterium infection (four), positive avian Mantoux test (five), or lack of response to human tuberculosis treatment (one) had been observed. One case was subsequently diagnosed as chronic granulomatous disease and illustrates that children with atypical mycobacterial pulmonary infection should have their immune status fully investigated. Bronchial obstruction was observed in eight cases, and of these, endobronchial disease was found in six children. The diagnosis of atypical mycobacterial disease is difficult, and a negative avian Mantoux test does not exclude the diagnosis. The availability of clarithromycin and rifabutin has offered new therapeutic options in treating atypical mycobacterial pulmonary infection, but management of these cases can be prolonged and difficult.

Bronchial Diseases↗

PubMed1998

Lung deposition of budesonide from turbuhaler in asthmatic children.

UNLABELLED: The aim of our study was to evaluate the effect of age on lung deposition of radiolabelled budesonide, delivered as a dry powder via Turbuhaler to asthmatic children. A group of 23 asthmatic children, aged 6 to 16 years, with relatively stable asthma inhaled 99mTc-labelled budesonide from a dry powder inhaler (Turbuhaler). Body and lung deposition was assessed using a gamma camera. The mean (range) median peak inspiratory flow during inhalation was 65 1 x min(-1) (45 to 76 1 x min(-1)). Mean (range) total lung deposition of 99mTc-labelled budesonide, expressed as a percentage of the metered dose, was 29.1% (15.6-47.2%) and was positively and significantly correlated with age, height and peak inspiratory flow. CONCLUSION: Total lung deposition of radiolabelled budesonide from a dry powder inhaler (Turbuhaler), is age dependent in children with moderate asthma. However, lung deposition is still satisfactory, even in younger children with lower peak inspiratory flows.

Adolescent↗

PubMed1998

Salbutamol delivery from a hydrofluoroalkane pressurized metered-dose inhaler in pediatric ventilator circuits: an in vitro study.

STUDY OBJECTIVES: The aim of our study was to determine the in vitro delivery of salbutamol from a pressurized metered-dose inhaler (pMDI) containing hydrofluoroalkane (HFA) propellant through various delivery devices to four models of a pediatric lung. DESIGN: To determine the effect of electrostatic charge, delivery of salbutamol was initially assessed with a multistage liquid impinger (MSLI) through an inline nonchamber device (Baxter MDI Adapter) and a small (Aerochamber MV) and a large (Nebuhaler) inline chamber device. Following this, the delivery was assessed to four lung models appropriate for a child of 70 kg, 50 kg, 15 kg, and 4 kg, with the same three reduced static devices inserted directly into a pediatric ventilator circuit. MEASUREMENTS AND RESULTS: Reduction of electrostatic charge improved small particle delivery through holding chambers to the MSLI by 12 to 14%. In the ventilator model, the mean delivery was between 1.9% and 5.4% for the nonchamber device, between 14.3% and 27.2% for the small holding chamber, and between 7.2% and 25.7% for the large holding chamber. Delivery was the least efficient in the 4-kg model compared to the 70-kg, 50-kg, and 15-kg models. CONCLUSIONS: Salbutamol from an HFA pMDI is delivered efficiently through inline holding chambers with reduced static in pediatric ventilator settings. A large holding chamber has no advantage over a small holding chamber. In addition, salbutamol delivery is more efficient through a holding chamber than through a nonchamber device.

Administration, Inhalation↗

PubMed1997

Aerosol delivery to wheezy infants: a comparison between a nebulizer and two small volume spacers.

Inhalation therapy for wheezy infants with either a nebulizer or a pressurized metered-dose inhaler (pMDI) through a spacer is common practice. The aim of our study was to compare aerosol delivery to wheezy infants from a nebulizer and from a pMDI via two small volume spacers. Twenty wheezy infants (aged 4-12 months) were recruited. They inhaled salbutamol from a Pari-Baby nebulizer, from a detergent-coated Babyhaler, and from a Nebuchamber in random order. A filter was placed between the inhalation systems and the patients. The amount of salbutamol deposited on the filter was measured using an ultraviolet spectrophotometer and was expressed as a percentage of the total nebulized or actuated doses. The mean total nebulized dose for the Pari-Baby (1030 micrograms) was higher (P < 0.001) than the mean actuated dose from a pMDI for the Babyhaler (374 micrograms) and for the Nebuchamber (378 micrograms). Mean drug deposition on the filter was 40.2% (150 micrograms) of the total actuated dose for the detergent-coated Babyhaler and 40.7% (154 micrograms) of the total actuated dose for the Nebuchamber. There was no significant difference in drug deposition on the filter between the two spacers. Mean drug deposition on the filter was 25.3% (260 micrograms) of the total nebulized dose for the Pari-Baby nebulizer. There was no weight dependence in drug deposition on the filter for the two spacers, but, drug deposition increased with the subject's weight for the nebulizer. We have shown that aerosol delivery to wheezy infants from a pMDI through small volume spacers is effective and that a higher percentage of the total amount of salbutamol is delivered than from a nebulizer. The weight dependence in drug deposition for the nebulizer can be of clinical relevance.

Administration, Inhalation↗

PubMed1997

Fc epsilon R1-beta polymorphism and total serum IgE levels in endemically parasitized Australian aborigines.

Endemic helminthic infection is a major public-health problem and affects a large proportion of the world's population. In Australia, helminthic infection is endemic in Aboriginal communities living in tropical northern regions of the continent. Such infection is associated with nonspecific (polyclonal) stimulation of IgE synthesis and highly elevated total serum IgE levels. There is evidence that worm-infection variance (i.e., human capacity of resistance) and total serum IgE levels may be related to the presence of a major codominant gene. The beta chain of the high-affinity IgE receptor, Fc epsilon R1-beta, has been previously identified as a candidate for the close genetic linkage of the 11q13 region to IgE responses in several populations. We show a biallelic RsaI polymorphism in Fc epsilon R1-beta to be associated with total serum IgE levels (P = .0001) in a tropical population of endemically parasitized Australian Aborigines (n = 234 subjects). The polymorphism explained 12.4% of the total residual variation in serum total IgE and showed a significant (P = .0000) additive relationship with total serum IgE levels, across the three genotypes. These associations were independent of familial correlations, age, gender, racial admixture, or smoking status. Alleles of a microsatellite repeat in intron 5 of the same gene showed similar associations. The results suggest that variation in Fc epsilon R1-beta may regulate IgE-mediated immune responses in this population.

Alleles↗

PubMed1997

Methacholine responsiveness using the raised volume forced expiration technique in infants.

Infant lung function can be assessed with the tidal volume "squeeze" technique or, over an extended volume range, with the newer raised volume forced expiration technique (RVFET). We assessed methacholine responsiveness in 11 infants, measuring both maximal expiratory flow at functional residual capacity (V.max,FRC)with the tidal volume technique, and forced expiratory volume/time (FEV(t)) with RVFET. We used a standard methodology for the former. FEV(t) was measured by inflating the infant's lungs to 20 cm H2O and forcing expiration using a jacket setup to transmit a pressure of 20 cm H2O to the airway. Lung function was measured at baseline and after methacholine inhalations, increasing from 0.1 g/L to 10 g/L in half log dosage increments (DI). The provocative concentrations (PC) of methacholine leading to a 40% fall in V.max,FRC and a 15 or 20% fall in FEV(t) were calculated. The mean provocative concentration of methacholine required to produce a 40% fall in V.max,FRC was less than that required to produce a 20% fall in FEV0.5 by 0.39 DI (95% CI, -0.60 to 1.38) and less than that required to produce a 20% fall in FEV0.75 by 0.42 DI (95%, CI, -0.54 to 1.39). Similarly, the provocative concentration of methacholine required to produce a 40% fall in V.max,FRC was less than that required to produce a 15% fall in FEV0.5 by 0.14 DI (95% CI, -0.99 to 1.28) or a 15% fall in FEV0.75 by 0.13 DI (95% CI, -0.80 to 1.08), but the differences were small and not significant. Despite these differences the agreement between the two methods was good, and bronchoconstriction was not attenuated by the forced inspiration delivered by the raised volume maneuver. We conclude that the raised volume forced expiration technique is able to detect methacholine-induced bronchoconstriction.

Bronchial Provocation Tests↗

PubMed1997

Influence of driving pressure on raised-volume forced expiration in infants.

The raised-volume forced-expiration technique measures infant lung function over an extended volume range. To improve comparisons between individuals and populations, we investigated the influence of jacket pressure on outcome variables in 21 infants. To quantify pressure transmitted from the jacket to the pleural space at a given lung volume, the jacket was inflated against an occluded airway, and the increase in pressure at the mouth was measured. Flow-volume curves were recorded at transmitted pressure (Ptrans) values ranging from 0 to 41.9 cm H20. The effect of Ptrans on the FEV measures of FEV0.5, FEV0.75, and FVC, and on the forced expiratory flow measures of FEF25%, FEF50% and FEF75% was assessed. At Ptrans values between 0 to 20 cm H20, a significant positive relationship existed between transmitted pressure (Ptrans) and all outcome variables except FVC. At higher Ptrans values, all outcome variables demonstrated pressure independence, with the exception of FEF25% (which remained positive) and FVC (which was negative in a subgroup of wheezy infants). FEF75% values tended to decrease at Ptrans values > 25 cm H20. At Ptrans values between 20 and 25 cm H20, most outcome variables are pressure independent. This range is therefore the most suitable for use with the raised-volume forced expiration technique.

Female↗

PubMed1996

Effects of maternal smoking during pregnancy and a family history of asthma on respiratory function in newborn infants.

INTRODUCTION: Infants of mothers who smoke have reduced respiratory function and are more likely to develop wheezing. Little evidence is available on the effect of in-utero cigarette-smoke exposure as opposed to postnatal exposure to environmental tobacco smoke. We used a previously validated non-invasive method to measure the time to peak tidal expiratory flow (tPTEF) as a proportion of expiratory time (tE) in newborn infants soon after birth to examine the effects of a family history of asthma and in-utero cigarette-smoke exposure on the infants' respiratory function. METHODS: We collected respiratory-function data from 500 healthy infants of mothers taking part in the Western Australia Pregnancy Cohort Study. During behaviourally defined quiet sleep, measurements were obtained a median of 58 h (range 26-159) after the infants were born. We used uncalibrated inductance plethysmography. The uncalibrated volume signal was differentiated to flow and used to calculate respiratory rate, total inspiratory time, tE, and tPTEF. Mothers answered questionnaires on demographic, medical, and pregnancy characteristics, including smoking history. Serum cotinine measurements were available to validate self-reported smoking history in a subset of mothers (238). RESULTS: Data suitable for analysis were obtained from 461 infants. In multivariate regression analysis, lower values of tPTEF/tE were independently associated with respiratory rate (beta coefficient per 10 breaths/min 0.018 [SE 0.005], p < 0.01), age (beta coefficient per 10 h -0.008 [0.003], p < 0.01), maternal smoking during pregnancy (> 10 cigarettes daily; beta coefficient -0.049 [0.022], p < 0.05), maternal hypertension during pregnancy (-0.037 [0.015], p < 0.02), and a family history of asthma (-0.028[0.014], p < 0.05). CONCLUSIONS: In-utero smoke exposure, a family history of asthma, and maternal hypertension during pregnancy are associated with reduced respiratory function after birth. We speculate that these factors adversely affect lung development in utero.

Asthma↗

PubMed1996

Effect of asthma treatment on urinary growth hormone excretion in children.

We measured growth hormone (GH) concentrations in first morning urine samples in 110 prepubertal children to determine whether asthma therapies affected GH secretion. The children with asthma were assigned to two groups depending on their asthma treatments: 1) 16 children with a history of asthma, currently not on any treatment, and 2) asthmatics taking inhaled corticosteroids (n = 37), short-term oral corticosteroids (n = 15), or long-term non-corticosteroidal therapies (n = 19). Results obtained from these children were compared with a control group of healthy prepubertal children (n = 23) without previous or current symptoms of asthma. Five consecutive urine samples were collected from each child, and GH concentrations (corrected for urine creatinine) were determined by an enzyme immunoassay. The mean (+/- SD) urine GH concentration determined in the control group (23 healthy prepubertal children) was 15.6 +/- 8.7 ng/L (1.88 +/- 1.29 ng GH/mmol creatinine). The mean (+/- SD) urine GH concentrations in overnight samples were similar in untreated asthmatics (14.1 +/- 6.1 ng/L) and in the treatment groups (14.1 +/- 7.7 ng/L, inhaled corticosteroids; 16.5 +/- 11.7 ng/L, oral corticosteroids; 15.9 +/- 9.8 ng/L, long-term non-corticosteroidal therapies). Irrespective of the manner of expression of urine GH (ng/L) or after correction for urine creatinine concentration (ng GH/mmol), no significant differences were found in the GH excretion among any of the groups. In this study, the intra-individual coefficient of variation for urine GH, expressed as ng/L, ranged between 11 and 87% (median, 32%). When the urine GH was expressed as ng GH/mmol creatinine, the coefficient of variation ranged between 12 and 92% (median, 35%), accounting for approximately 60% of the inter-individual coefficient of variation (mean CV, 56%) and 47% when the urine GH is expressed as ng GH/mmol creatinine. We were unable to determine any short-term differences in urine GH excretion between non-asthmatic children and asthmatics treated with inhaled corticosteroids, oral corticosteroids, or bronchodilators. Our results suggest that there is not an adverse effect of current corticosteroid therapies for childhood asthma on GH secretion.

Anti-Asthmatic Agents↗

PubMed1996

Effect of electrostatic charge, flow, delay and multiple actuations on the in vitro delivery of salbutamol from different small volume spacers for infants.

BACKGROUND: A study was undertaken to determine the influences of electrostatic charge, flow, delay, and multiple actuations on the in vitro delivery of salbutamol generated by a pressurised metered dose inhaler (pMDI) from small volume spacers used in infants. METHODS: Ten actuations from a salbutamol pMDI were drawn at different flow rates after either single or multiple actuations, with or without delay, through either static or reduced static spacers. An ionic detergent was used to reduce the charge of plastic spacers (Babyhaler, Babyspacer, Aerochamber, Nebuhaler). Electrostatic charge was measured using an electrometer. A multistage liquid impinger was used to determine the particle size distribution of the output of the pMDI through the spacers. RESULTS: Electrostatic charge on the surface of plastic spacers had the greatest influence on delivery, causing a decrease in drug delivery. Reducing charge by coating the surface with ionic detergent resulted in an increase of 46.5-71.1% (p < 0.001) in small (< 6.8 microns) particle delivery from small volume plastic spacers. Lower flow, delay, and multiple actuations resulted in decreased delivery from static spacers. Lower flow resulted in a decrease of 15% in small (< 9.6 microns) particle delivery. Delay and multiple actuations resulted in a decrease of 40.7% and 76.0%, respectively, in small (< 6.8 microns) particle delivery. The influences of lower flow, delay, and multiple actuations were greatly reduced or even eliminated by reducing charge. However, multiple actuations still resulted in a significant decreased delivery (p < 0.05). The reduced static Nebuhaler had a higher delivery than all small volume spacers. CONCLUSIONS: Electrostatic charge has a major influence on the delivery of salbutamol from small volume spacers. Using a metal spacer or ionic detergent coating of plastic spacers resulted in no or reduced charge and hence in improved delivery. Lower flow, delay, and multiple actuations played a major part only in static spacers.

Albuterol↗

PubMed1996

Electrostatic charge on a plastic spacer device influences the delivery of salbutamol.

The aim of this study was to determine whether electrostatic charge on a plastic spacer decreases the delivery of salbutamol from a pressurized metered-dose inhaler (pMDI) and, if so, to find an optimal and practical treatment to remove the charge. Ten single actuations from a salbutamol pMDI were drawn through different Volumatic spacers at a constant flow of 60 L.min-1. The efficacies of different methods of removing charge were tested, including detergent coating of the spacers. A multistage liquid impinger was used to determine the particle size distribution of the output of the pMDI through the Volumatic spacers. The electrostatic charge on the inner surface of the spacers was measured both quantitatively with an electrometer, and qualitatively by the attraction of a thin strip of cellulose membrane to the wall of the spacer. Each experiment was repeated four times. Ionic detergent coating of the spacers removed the charge for at least 24 h. This resulted in an increase of 55-70% in small particle (< 6.8 microns) delivery compared to delivery from new spacers with high charge. We have demonstrated that electrostatic charge plays a major role in the delivery of salbutamol through plastic spacers. Adequate treatment with ionic detergent removes the charge and improves drug delivery.

Albuterol↗