Dibutyl Phthalate Augments Allergen-induced Lung Function Decline and Alters Human Airway Immunology. A Randomized Crossover Study.

Rationale: Phthalates are a group of chemicals used in common commercial products. Epidemiological studies suggest that phthalate exposure is associated with development or worsening of allergic diseases such as asthma. However, effects of dibutyl phthalate (DBP) or other phthalates found in high concentrations in indoor air have never been examined in allergic individuals in a controlled exposure setting.Objectives: To investigate the airway effects in humans caused by inhalation of a known concentration of a single phthalate, DBP.Methods: In a randomized crossover study, 16 allergen-sensitized participants were exposed to control air or DBP for 3 hours in an environmental chamber followed immediately by an allergen inhalation challenge. Bronchoalveolar wash and lavage were obtained 24 hours after exposure. Lung function, early allergic response, airway responsiveness, inflammation, immune mediators, and immune cell phenotypes were assessed after DBP exposure.Measurements and Main Results: DBP exposure increased the early allergic response (21.4% decline in FEV1 area under the curve, P = 0.03). Airway responsiveness was increased by 48.1% after DBP exposure in participants without baseline hyperresponsiveness (P = 0.01). DBP increased the recruitment of BAL total macrophages by 4.6% (P = 0.07), whereas the M2 macrophage phenotype increased by 46.9% (P = 0.04). Airway immune mediator levels were modestly affected by DBP.Conclusions: DBP exposure augmented allergen-induced lung function decline, particularly in those without baseline hyperresponsiveness, and exhibited immunomodulatory effects in the airways of allergic individuals. This is the first controlled human exposure study providing biological evidence for phthalate-induced effects in the airways.Clinical trial registered with www.clinicaltrials.gov (NCT02688478).

The effectiveness of Reslizumab in severe asthma treatment: a real-world experience.

BACKGROUND: Increased numbers of blood and sputum eosinophils are associated with higher exacerbation frequency and increased asthma severity. In clinical trials, targeting Interleukin-5 has been shown to be a useful therapeutic strategy for patients with severe eosinophilic asthma. METHODS: Twenty-six patients have been commenced on Reslizumab in our institution since early 2017. Safety and clinical efficacy parameters were recorded at regular intervals. RESULTS: Mean ACQ-6 score at the start of treatment was 3.5. The average number of exacerbations in the year preceding treatment was 8.3 per person. 30% of patients had been admitted to hospital at least once over the 12 months preceding therapy. 54% of our patients were on long term oral steroid. Our data showed sustained improvement of Asthma control (Mean improvement in ACQ-6 was 1.7 at 1 year, and 2.0 at 2 years, P = 0.0001). Of the patients who were on long term systemic steroids, 35.7% discontinued steroids completely, with a mean reduction of prednisolone dose of 5.2 mg at 1 year. There was a 79% reduction in the annual exacerbation frequency at 1 year, and 88% at 2 years (P = < 0.0001). Modest, albeit statistically significant increases in creatine kinase which seemed to plateau by 1 year were noted. CONCLUSIONS: Overall, Reslizumab was well tolerated with discontinuation of treatment due to side effects recorded in only one patient. Our data confirm the utility of anti-IL5 therapy in a carefully selected phenotype of severe asthma with evidence of eosinophilic airway inflammation.

Lung function response and side effects to rapamycin for lymphangioleiomyomatosis: a prospective national cohort study.

RATIONALE: Mechanistic target of rapamycin inhibitors reduce loss of lung function in lymphangioleiomyomatosis (LAM), although their benefit varies between individuals. We examined lung function response and side effects to rapamycin in a national cohort. METHODS: Subjects were receiving rapamycin for progressive lung disease. Clinical evaluation, detailed phenotyping, serial lung function, rapamycin and safety monitoring were performed according to a clinical protocol. Lung function change, measured as FEV1 slope (ΔFEV1), was reported for those treated for 1 year or longer. RESULTS: Rapamycin was associated with improved ΔFEV1 in 21 individuals where pretreatment data were available (p<0.0001). In 47 treated for a mean duration of 35.8 months, mean ΔFEV1 was +11 (SD 75) mL/year, although it varied from +254 to -148 mL/year. The quartile with the highest positive ΔFEV1 had greater pretreatment FEV1 (p=0.02) and shorter disease durations (p=0.02) than the lowest quartile. Serum rapamycin level was positively associated with side effects (p=0.02) but not ΔFEV1 over 1 year. Within the first month of therapy, apthous ulcers, nausea and diarrhoea were associated with higher rapamycin levels. Acne, oedema and menstrual irregularities tended to increase over the first year of therapy. At the end of observation, the prevalence of side effects was 5% or less. CONCLUSIONS: Rapamycin reduces lung function loss in LAM, although in some, ΔFEV1 continues to fall at an accelerated rate. Poor response to rapamycin was associated with lower pretreatment lung function and longer disease duration but not serum level. Early intervention with low-dose rapamycin may preserve lung function and reduce side effects.

Influence of mouthwashes on extended exhaled nitric oxide (FENO) analysis.

Fractional exhaled nitric oxide (FENO) is used to assess eosinophilic inflammation of the airways. FENO values are influenced by the expiratory flow rate and orally produced NO. We measured FENO at four different expiratory flow levels after two different mouthwashes: tap water and carbonated water. Further, we compared the alveolar NO concentration (CANO), maximum airway NO flux (J'awNO) and airway NO diffusion (DawNO) after these two mouthwashes. FENO was measured in 30 volunteers (healthy or asthmatic) with a chemiluminescence NO-analyser at flow rates of 30, 50, 100 and 300 mL/s. A mouthwash was performed before the measurement at every flow rate. The carbonated water mouthwash significantly reduced FENO compared to the tap water mouthwash at all expiratory flows: 50 mL/s (p < .001), 30 mL/s (p = .001), 100 mL/s (p < .001) and 300 mL/s (p = .004). J'awNO was also significantly reduced (p = .017), however, there were no significant differences in CANO and DawNO. In conclusion, a carbonated water mouthwash can significantly reduce oropharyngeal NO compared to a tap water mouthwash at expiratory flows of 30-300 mL/s without affecting the CANO and DawNO. Therefore, mouthwashes need to be taken into account when comparing FENO results.

Effect of nasally exhaling budesonide/formoterol dry powder inhaled at "fast" inspiratory flow on eosinophilic chronic rhinosinusitis
.

BACKGROUND: Budesonide (BUD)/formoterol (FM) dry powder inhaler has a feature that the fine particle fraction output is dependent on users' inspiratory flow rate. The aim of this study was to assess the amount of nasally exhaled BUD/FM inhaled in the different inspiratory flow rate. We also examined the effect of nasal exhalation of BUD/FM dry powder inhaled on radiographic evidence of sinonasal inflammation in asthmatic patients with eosinophilic chronic rhinosinusitis (ECRS). MATERIALS AND METHODS: The quantitative amount of nasally exhaled BUD/FM was analyzed by high-performance liquid chromatography in 3 healthy subjects. We retrospectively evaluated the effect of nasal exhalation of BUD/FM dry powder inhaled at > 60 L/min on radiographic evidence of sinonasal inflammation, which was assessed according to the Lund-Mackay staging (LMS) system, in 7 consecutive patients with asthma and ECRS. RESULTS: The amount of nasally exhaled BUD in the setting of inhaling BUD/FM dry powder inhaler at 60 L/min (subject 1: 25.8 ng/mL; subject 2: 37.3 ng/mL; subject 3: 30.0 ng/mL) was high compared to at 30 L/min (subject 1: 9.3 ng/mL; subject 2: 4.1 ng/mL; subject 3: 9.2 ng/mL) in each healthy subject. Nasal exhalation of BUD/FM dry powder significantly reduced total (p = 0.018) and ethmoid LMS scores (p = 0.0077). CONCLUSION: Nasal exhalation technique of BUD/FM dry powder inhaled at "fast" inspiratory flow has a potential of simultaneously treating asthma and ECRS.
.

Mannitol challenge testing for asthma in a community cohort of young adults.

BACKGROUND AND OBJECTIVE: Mannitol challenge testing is an established tool for clinical asthma diagnosis, and can be performed outside of specialized respiratory laboratories. Despite applicability in both clinical and non-clinical populations, with different pre-test asthma probabilities, differences in diagnostic properties have not been well explored. This study aimed to quantify the diagnostic utility of mannitol challenge testing for asthma in a community cohort and a symptomatic wheezing subset of this cohort. METHODS: During the 22-year follow-up of the Western Australian Pregnancy (Raine) Cohort, 772 participants (384 males) completed mannitol challenge and skin prick testing and respiratory health questionnaires, of whom 148 reporting wheeze in the past 12 months were included in a wheezing subset. RESULTS: Responsiveness to mannitol had low sensitivity (19%) and high specificity (97%) to identify current asthma in the complete cohort, with positive and negative predictive values (PPV and NPV) of 45% and 92%, respectively. Within the wheezing subset, sensitivity (19%) and specificity (94%) remained similar, but PPV increased to 79%, and NPV decreased to 52%. CONCLUSION: Our findings support previously reported high specificity and good PPV for mannitol challenge testing in symptomatic wheezing populations, and highlight the need for caution when interpreting mannitol test results in non-clinical populations.

[Autonomic regulation at emotional stress under hypoxic conditions in the elderly with physiological and accelerated aging: effect of hypoxic training].

The effect of hypoxic training on autonomic regulation in psycho-emotional stress conditions in hypoxic conditions in older people with physiological (25 people) and accelerated (28 people) aging respiratory system. It is shown that hypoxic training leads to an increase in vagal activity indicators (HF) and reduced simpatovagal index (LF/HF), have a normalizing effect on the autonomic balance during stress loads in older people with different types of aging respiratory system.

Effect of albuterol on expiratory resistance in mechanically ventilated patients.

BACKGROUND: In mechanically ventilated patients with COPD, the response of the expiratory resistance of the respiratory system (expiratory R(RS)) to bronchodilators is virtually unknown. OBJECTIVE: To examine the effect of inhaled albuterol on expiratory R(RS), and the correlation of albuterol-induced changes in expiratory R(RS) with end-inspiratory resistance and the expiratory flow-volume relationship. METHODS: We studied 10 mechanically ventilated patients with COPD exacerbation, before and 30 min after administration of albuterol. We obtained flow-volume curves during passive expiration, divided the expired volume into 5 equal volume slices, and then calculated the time constant and dynamic effective deflation compliance of the respiratory system (effective deflation C(RS)) of each slice via regression analysis of the volume-flow and post-occlusion volume-tracheal pressure relationships, respectively. For each slice we calculated expiratory R(RS) as the time constant divided by the effective deflation C(RS). RESULTS: Albuterol significantly decreased the expiratory R(RS) (mean expiratory R(RS) 42.68 ± 17.8 cm H(2)O/L/s vs 38.08 ± 16.1 cm H(2)O/L/s) and increased the rate of lung emptying toward the end of expiration (mean time constant 2.51 ± 1.2 s vs 2.21 ± 1.2 s). No correlation was found between the albuterol-induced changes in expiratory R(RS) and that of end-inspiratory resistance. Only at the end of expiration did albuterol-induced changes in the expiratory flow-volume relationship correlate with changes in expiratory R(RS) in all patients. CONCLUSIONS: In patients with COPD, albuterol significantly decreases expiratory resistance at the end of expiration. In mechanically ventilated patients, neither inspiratory resistance nor the whole expiratory flow-volume curve may be used to evaluate the bronchodilator response of expiratory resistance.

[The repeatability of forced expiratory manoeuvres in 4- to 6-year-old children with intermittent bronchial asthma in healthy and in exacerbated status]. / Reproduzierbarkeit der FEV1 bei Kindern von 4 bis 6 Jahren mit intermittierendem Asthma bronchiale im beschwerdefreien sowie im Beschwerdeintervall.

INTRODUCTION: The question about the repeatability of forced expiratory manoeuvres in childhood lung function testing is of scientific and clinical interest. The following study investigated to what extent children ≥ 4 to < 7 years of age with intermittent bronchial asthma are able to produce reproducible lung function measurements on the one hand in the healthy status and on the other hand in an exacerbated status. METHOD: 64 children at the age of ≥ 4 to < 7 years with intermittent preschool bronchial asthma performed lung function measurements in the healthy status and again in an exacerbated status. FEV (1) values from the measurements were analysed according to ATS/ERS guidelines concerning repeatability. RESULTS: According to the new ATS/ERS guidelines 74.6 % of the children could perform at least 2, and 59.3 % could perform 3 repeatable measurements in the healthy status. In the exacerbated status this was 87.5 % and 68.8 %, respectively. There were no significant differences between the healthy and the exacerbated status and between the age groups. Compared to former repeatability criteria, children of this age group can perform significantly more reproducible measurements (p < 0.0001). CONCLUSION: The ATS/ERS guidelines from 2007 simplify the repeatability of forced expiratory manoeuvres in children at ≥ 4 to < 7 years of age compared to the former criteria. Repeatability is not reduced in the exacerbated status. 74.6 % of children in this age group can produce repeatable lung function measurements.

Effect of heliox breathing on flow limitation in chronic heart failure patients.

Patients with chronic heart failure (CHF) exhibit orthopnoea and tidal expiratory flow limitation in the supine position. It is not known whether the flow-limiting segment occurs in the peripheral or central part of the tracheobronchial tree. The location of the flow-limiting segment can be inferred from the effects of heliox (80% helium/20% oxygen) administration. If maximal expiratory flow increases with this low-density mixture, the choke point should be located in the central airways, where the wave-speed mechanism dominates. If the choke point were located in the peripheral airways, where maximal flow is limited by a viscous mechanism, heliox should have no effect on flow limitation and dynamic hyperinflation. Tidal expiratory flow limitation, dynamic hyperinflation and breathing pattern were assessed in 14 stable CHF patients during air and heliox breathing at rest in the sitting and supine position. No patient was flow-limited in the sitting position. In the supine posture, eight patients exhibited tidal expiratory flow limitation on air. Heliox had no effect on flow limitation and dynamic hyperinflation and only minor effects on the breathing pattern. The lack of density dependence of maximal expiratory flow implies that, in CHF patients, the choke point is located in the peripheral airways.

Efficacy and safety of high-doses sublingual immunotherapy in ultra-rush scheme in children allergic to grass pollen.

BACKGROUND: Although sublingual immunotherapy (SLIT) has been used with increasing frequency, the data on the efficacy of SLIT in pediatric asthma are limited. AIM: The aim of our study was to evaluate the efficacy and the safety of high-dose SLIT given pre-seasonally and co-seasonally in an ultra-rush scheme in children with bronchial asthma allergic to grass pollen. METHODS: Fifty children with asthma, aged 6-17, sensitive to grass pollen, participated in the 2-year prospective, randomized, double-blind, placebo-controlled trial, to investigate the efficacy and safety of SLIT (Staloral 300 IR, Stallergenes SA, 25 microg major allergens) as a standardized extract of five grass pollen with ultra-rush induction. RESULTS: SLIT significantly improved asthma symptom scores (41% vs. placebo group), reduced nasal symptoms (25% vs. placebo group) and the use of rescue medications (10% vs. placebo group), improved forced expiratory volume in 1 s, but had no effect on ocular symptoms, nasal hyper-reactivity, peak expiratory flow and forced expiratory volume between 25% and 75% of vital capacity. Serum levels of immunoglobulin E and IgG4 did not change after SLIT. After the second season of SLIT, an improvement in bronchial hyperresponsiveness was observed; however, compared with placebo, this effect was not significant. Among all subjects in SLIT group, predominantly local reactions have been recorded in 59% of subjects in the first year of treatment and in 35% in the second. CONCLUSIONS: Our study indicated that high-dose ultra-rush, co-seasonal SLIT given for 2 years, was safe and reduced a multiple symptom-medication score.

Responses of FEV6, FVC, and FET to inhaled bronchodilator in the adult general population.

BACKGROUND: The assessment of bronchodilator-induced change in forced vital capacity (FVC) is dependent on forced expiratory time (FET) in subjects with airflow limitation. Limited information is available on the concurrent responses of FVC, forced expiratory volume in six seconds (FEV6), and FET in the bronchodilation test among patients with obstructive airways disease or in the general population. The aim of this study was to assess the changes in FEV6, FVC, and FET, and their relationships in a standardized bronchodilation test in the general population. METHODS: We studied bronchodilation response in a general adult population sample of 628 individuals (260 men, 368 women) with flow-volume spirometry. The largest FVC, the corresponding FET and the largest FEV6 both at the baseline and after 0.4 mg of inhaled salbutamol were selected for analysis. RESULTS: After administration of salbutamol FEV6 decreased on average -13.4 (95% CI -22.3 to -4.5) ml or -0.2% (-0.4% to 0.0%) from the baseline. The 95th percentile of change in FEV6 was 169.1 ml and 5.0%. FVC decreased on average -42.8 (-52.4 to -33.3) ml or -1.0% (-1.2% to -0.7%). Concurrently FET changed on average -0.2 (-0.4 to 0.0) seconds or 0.4% (-1.4% to 2.3%). There were four subjects with an increase of FVC over 12% and only one of these was associated with prolonged FET after salbutamol. Changes in FEV6 and FVC were more frequently positive in subjects with reduced FEV1/FVC in baseline spirometry. CONCLUSION: In general adult population, both FEV6 and FVC tended to decrease, but FET remained almost unchanged, in the bronchodilation test. However, those subjects with signs of airflow limitation at the baseline showed frequently some increase of FEV6 and FVC in the bronchodilation test without change in FET. We suggest that FEV6 could be used in assessment of bronchodilation response in lieu of FVC removing the need for regulation of FET during bronchodilation testing.

Acute effects of higher than standard doses of salbutamol and ipratropium on tiotropium-induced bronchodilation in patients with stable COPD.

Knowledge on the effects of the additive bronchodilatory effects of short-acting agents on the top of the effect of long-acting bronchodilators is limited. In this trial, we examined the influence of higher than conventional doses of the short-acting inhaled beta(2)-adrenergic agent salbutamol and the short-acting anticholinergic drug ipratropium bromide on bronchodilation induced by a regular treatment with the long-acting anticholinergic drug tiotropium 18 microg/day in 30 patients with stable COPD. On 3 separate days, a dose-response curve to inhaled salbutamol (100 microg puff-1), ipratropium bromide (20 microg puff-1) or placebo was constructed 3h after inhalation of the last dose of tiotropium, using one puff, one puff, two puffs and two puffs, for a total cumulative dose of 600 microg salbutamol or 120 microg ipratropium bromide. Doses were given at 30-min intervals and measurements made 15 min after each dose. At the highest cumulative dose, salbutamol showed a trend to be more effective than ipratropium bromide in improving FEV(1) (0.157 L vs 0.125 L), and reducing sRaw (-4.52 kPa/s vs 3.57 kPa/s), although the differences between the two treatments were always not significant (p>0.05), whereas there was no substantial difference between the two drugs in changing FVC (0.179 L vs 0.168 L), IC (0.254 L vs 0.240 L), TGV (-0.444 L vs -0.441 L), TLC (-0.334 L vs -0.318 L) and RV (-0.467 L vs -0.498 L). Both drugs did not affect heart rate and SpO2. Our results indicate that there is not much difference in bronchodilation between adding higher than conventional doses of salbutamol or ipratropium bromide to tiotropium in patients with stable COPD. Effective improvement of the pulmonary function may be achieved in such a type of patients by adding salbutamol 600 microg or ipratropium bromide 120 microg to regular tiotropium. These is an interesting finding mainly for those COPD patients suffering from cardiovascular co-morbidities that are at highest risk of myocardial infarction, congestive heart failure, cardiac arrest and sudden cardiac death when treated with elevated doses of a beta(2)-agonist (EudraCT number: 2007-001597-82).

Steroid-sparing effects of pentoxifylline in pulmonary sarcoidosis.

BACKGROUND: Agents that target pro-inflammatory cytokines may be useful in pulmonary sarcoidosis. OBJECTIVE: To determine effectiveness of a non-selective cyclic nucleotide phosphodiesterase (PDE) inhibitor, pentoxifylline (POF). DESIGN: Randomized, double-blind, placebo-controlled trial, SETTING: Clinical Research Center, National Institutes of Health. PATIENTS: 27 patients with biopsy-confirmed pulmonary sarcoidosis receiving prednisone. INTERVENTION: Placebo or POF (1200-2000 mg/day) for 10 months, as prednisone was tapered. MEASUREMENTS: Primary endpoints: sustained improvement in two or more pulmonary function parameters, or a combination of one pulmonary function parameter and dyspnea. RESULTS: Except for one patient, primary endpoints were not reached in POF-treated patients. Therefore, a post hoc analysis was performed. The observed relative risk reduction for flares associated with POF treatment was 54.9% (95% CI 0.21, 0.89) and the absolute risk reduction was 50.6% (95% CI 0.22, 0.80). Compared to placebo treatment, in the POF group, the mean prednisone dose was lower at 8 and 10 months (p = 0.007 and 0.01 respectively), and there was a trend towards less prednisone usage over the entire study period (p = 0.053), as determined by cumulative change analysis. CONCLUSIONS: Although our exploratory post hoc analysis suggested that POF reduced flares and had steroid-sparing effects, given the study limitations, definitive conclusions cannot be drawn regarding the efficacy of POF in pulmonary sarcoidosis. In addition, gastrointestinal side-effects, at the doses used, would seem to limit the use of POF in treating pulmonary sarcoidosis. Overall, however, this trial may provide a basis for using more specific, better-tolerated, PDE inhibitors in future clinical trials.

Effects of time, albuterol, and budesonide on the shape of the flow-volume loop in children with asthma.

BACKGROUND: Assessment of asthma through spirometric analysis in children is challenging because of often normal FEV(1) values. OBJECTIVE: We used Mead's slope ratio (SR; (dV /dV)/(V /V)) to analyze the shape of the flow-volume loop. METHODS: We analyzed the effects of time, albuterol, and budesonide on FEV(1), FEV(1)/forced vital capacity (FVC) ratio, forced expiratory flow from 25% to 75% of expired volume, and Mead's SR both early (between 75% and 50% of FVC, SR61) and late (between 75% and 50% of FVC, SR35) in exhalation in the Childhood Asthma Management Program cohort at baseline, 4 months, and the end of the study in participants who received either inhaled placebo or budesonide twice daily. RESULTS: In the placebo group both SR61 and SR35 improved over time. Bronchodilator consistently improved both SR61 and SR35, without change in degree of improvement over time. Similarly, in the budesonide group time and bronchodilator each independently improved both SR61 and SR35. At 4 months and the end of the study, patients receiving budesonide had significant improvements in SR61 relative to patients receiving placebo, which was independent of bronchodilator effect. Budesonide and placebo were not different with respect to prebronchodilator or postbronchodilator SR35. CONCLUSION: Budesonide-treated patients have less concave flow-volume loops when compared with placebo-treated patients. Time and bronchodilator also make the flow-volume loop less concave. Furthermore, it appears that there are discrete bronchodilator- and corticosteroid-responsive components of airflow obstruction in pediatric asthma.

Deterioration in asthma control when subjects receiving fluticasone propionate/salmeterol 100/50 mcg Diskus are "stepped-down".

In this study, 647 subjects stable on fluticasone propionate/salmeterol Diskus 100/50 mcg BID (FSC) were randomized to continue FSC 100/50 mcg BID or "step down" to either fluticasone propionate (FP) 100 mcg BID, salmeterol (SAL) 50 mcg BID, or montelukast (MON) 10 mg once daily for 16 weeks. Overall asthma control significantly improved in the FSC group; whereas, "stepping down" to FP, SAL, or MON resulted in deterioration in asthma control, as determined by decreased measures of lung function and clinical features. This study provides support that treatment of both inflammation and smooth muscle dysfunction may be necessary to achieve and maintain asthma control in patients uncontrolled on ICS.

Dry powder inhalation of colistin in cystic fibrosis patients: a single dose pilot study.

BACKGROUND: Dry powder inhalation (DPI) may be an alternative to nebulisation of drugs in the treatment of chest infections in cystic fibrosis (CF) patients. In a pilot study the feasibility of a colistin dry powder inhaler (prototype Twincer) by a single dose in CF-patients was assessed and compared to nebulised colistin. METHODS: Ten CF-patients, chronically infected with P. aeruginosa, participated in a randomised cross over study. On two visits to the outpatient clinic, patients inhaled colistin sulphomethate as 25 mg dry powder (Twincer) or as 158 mg nebulised solution (Ventstream nebuliser, PortaNeb compressor). Pulmonary function tests were performed before, 5 and 30 min after inhalation. Serum samples were drawn prior to each dose and at 15, 45 min, 1.5; 2.5; 3.5 and 5.5 h after inhalation. RESULTS: The DPI was well tolerated by the patients: no significant reduction in FEV1 was observed. Relative bioavailability of DPI to nebulisation was approx. 140% based on actual dose and approx. 270% based on drug dose label claim. CONCLUSIONS: The colistin DPI (Twincer inhaler) is well tolerated and appreciated by CF-patients. Optimisation with respect to particle size and internal resistance of the inhaler is necessary to attain equivalent pulmonary deposition to liquid nebulisation.

Methadone-induced respiratory depression in the neonatal guinea pig.

Respiratory depression, the most serious side-effect of opioid treatment, is well documented for morphine, the most commonly used opioid in neonatal care. Less is known about methadone, a clinically relevant opioid analgesic, especially during neonatal development. This study was undertaken to determine the neonatal respiratory effects of methadone. We hypothesize that methadone is equipotent to morphine, compared to our previous morphine results in the same animal model, but has a much longer duration of action, due to its longer elimination half-life. Neonatal guinea pigs (3-14 days old) randomly received a single subcutaneous dose of methadone or saline. Using a non-invasive plethysmographic method, we measured ventilatory and metabolic parameters before injection and at intervals for 32 hr after injection while pups breathed "room air" or 5% CO(2) gas mixtures. Methadone-induced depression of ventilation was most evident during 5% CO(2) challenge. The onset of drug effects was within 15 min for all ages and doses, but the duration of action decreased with age. While the depth of methadone-induced respiratory depression did not depend on pup age, the control of breathing was different in 3-day-old pups, where inspiratory time increased fourfold; twice that of older pups. We conclude that methadone induces a naloxone reversible respiratory depression in guinea pig neonates and, in the very young, causes an abnormal breathing pattern due to changes in respiratory timing. Methadone is more potent than morphine with respect to neonatal respiratory depression, but surprisingly, the duration of methadone action was not longer than morphine.

Helium-oxygen ventilation in the presence of expiratory flow-limitation: a model study.

A comparison between air and heliox (80% helium-20% oxygen) ventilation was performed using a mathematical, non-linear dynamic, morphometric model of the respiratory system. Different obstructive conditions, all causing expiratory flow limitation (EFL), were simulated during mechanical ventilation to evaluate and interpret the effects of heliox on tidal EFL and dynamic hyperinflation. Relative to air ventilation, intrinsic positive end-expiratory pressure did not change with heliox if the obstruction was limited to the peripheral airways, i.e. beyond the seventh generation. When central airways were also involved, heliox reduced dynamic hyperinflation (DH) if the flow-limiting segment remained in the fourth to seventh airway generation during the whole expiration, but produced only minor effects if, depending on the contribution of peripheral to total apparent airway resistance, the flow-limiting segment moved eventually to the peripheral airways. In no case did heliox abolish EFL occurring with air ventilation, indicating that any increase in driving pressure would be without effect on DH. Hence, to the extent that chronic obstructive pulmonary disease (COPD) affects primarily the peripheral airways, and causes EFL through the same mechanisms operating in the model, heliox administration should not be expected to appreciably reduce DH in the majority of COPD patients who are flow-limited at rest.

The effects of antenatal smoking on lung function and respiratory symptoms in infants and children.

We highlight evidence demonstrating antenatal smoking exposure is an important risk factor for increased respiratory symptoms and lung function abnormalities in infants and children. Epidemiological studies have demonstrated an excess both of wheezing in the first two years after birth and asthma and persistent wheezing in older children. Lung function testing in children exposed to antenatal smoking has demonstrated a reduction in airway function. Antenatal exposure of nicotine to animal models results in pulmonary hypoplasia, fewer but larger alveoli and altered airway morphology. Pulmonary function testing, however, has not demonstrated that infant lung volume is affected by antenatal smoking exposure, other than due to the expected effect of smoking on somatic growth, but there is an adverse effect on airway development. There is no evidence that antenatal smoking exposure increases bronchial hyperreactivity, rather it may be associated with a diminished response to both bronchoconstrictors and bronchodilators in infants.