Inhaled frusemide against cold air induced bronchoconstriction in asthmatic children

Inhaled furosemide in hospitalized infants with viral bronchiolitis: a randomized, double-blind, placebo-controlled pilot study

OBJECTIVE

To evaluate the short and long-term clinical effects and the treatment-feasibility of inhaled-furosemide (IF) as compared with placebo via hood in hospitalized infants with viral-bronchiolitis (VB).

STUDY-DESIGN

A randomized, double-blind, placebo-controlled pilot-study was performed in previously healthy infants (0-12 months). Enrolled infants were randomized to receive either IF (2 mg/kg), or placebo nebulized by hood three times daily throughout the hospitalization. Clinical assessment (respiratory distress assessment instrument [RDAI]) was performed before, 30 and 60 min after the 1st daily inhalation. The short-term effects were evaluated by the RDAI, respiratory assessment change score (RACS) and oxygen requirement and the long-term effects by time to be weaned off oxygen, time to full enteral feeding, length of stay, and "ready to discharge" time.

RESULTS

Both groups (16 infants each) had comparable characteristics at study entry. Mean (+/-SD) age was 72 +/- 43 days, and 29/32 infants were RSV positive. Oxygen requirement (FiO(2)) decreased significantly at 30 min post-inhalation (30 +/- 9.2% to 26 +/- 7.1%, P < 0.05) only in the IF group. RACSs and long-term effects of both groups were comparable. Analysis of IF particles generated by the hood-nebulizer demonstrated that 36% and 49% of the particles were <3 and 5 microm, respectively. No side effects were observed during IF treatment.

CONCLUSION

Based on our pilot study, IF has no significant clinical effects in hospitalized infants with VB. IF via hood seems to be feasible and safe.

Diuretics in pediatrics : current knowledge and future prospects

This review summarizes current knowledge on the pharmacology, pharmacokinetics, pharmacodynamics, and clinical application of the most commonly used diuretics in children. Diuretics are frequently prescribed drugs in children. Their main indication is to reduce fluid overload in acute and chronic disease states such as congestive heart failure and renal failure. As with most drugs used in children, optimal dosing schedules are largely unknown and empirical. This is undesirable as it can potentially result in either under- or over-treatment with the possibility of unwanted effects. The pharmacokinetics of diuretics vary in the different pediatric age groups as well as in different disease states. To exert their action, all diuretics, except spironolactone, have to reach the tubular lumen by glomerular filtration and/or proximal tubular secretion. Therefore, renal maturation and function influence drug delivery and consequently pharmacodynamics. Currently advised doses for diuretics are largely based on adult pharmacokinetic and pharmacodynamic studies. Therefore, additional pharmacokinetic and pharmacodynamic studies for the different pediatric age groups are necessary to develop dosing regimens based on pharmacokinetic and pharmacodynamic models for all routes of administration.

Na+-K+-2Cl− cotransporters and Cl− channels regulate citric acid cough in guinea pigs

Loop diuretics have been shown to inhibit cough and other airway defensive reflexes via poorly defined mechanisms. We test the hypothesis that the furosemide-sensitive Na+-K+-2Cl− cotransporter (NKCC1) is expressed by sensory nerve fibers innervating the airways where it plays an important role in regulating sensory neural activity. NKCC1 immunoreactivity was present on the cell membranes of most nodose and jugular ganglia neurons projecting to the trachea, and it was present on the peripheral terminals of putative mechanosensory nerve fibers in the airways. In urethane-anesthetized, spontaneously breathing guinea pigs, bolus application of citric acid (1 mM to 2 M) to an isolated and perfused segment of the tracheal mucosa evoked coughing and respiratory slowing. Removal of Cl− from the tracheal perfusate evoked spontaneous coughing and significantly potentiated cough and respiratory slowing reflexes evoked by citric acid. The NKCC1 inhibitor furosemide (10–100 μM) significantly reduced both the number of coughs evoked by citric acid and the degree of acid-evoked respiratory slowing ( P < 0.05). Localized tracheal pretreatment with the Cl− channel inhibitors DIDS or niflumic acid (100 μM) also significantly reduced cough, whereas the GABAA receptor agonist muscimol potentiated acid-evoked responses. These data suggest that vagal sensory neurons may accumulate Cl− due to the expression of the furosemide-sensitive Cl− transporter, NKCC1. Efflux of intracellular Cl−, in part through calcium-activated Cl− channels, may play an important role in regulating airway afferent neuron activity.

Aerosolized diuretics for preterm infants with (or developing) chronic lung disease

BACKGROUND

Lung disease in preterm infants is often complicated with lung edema.

OBJECTIVES

The aim of this review is to assess the risks and benefits of aerosolized diuretic administration in preterm infants with or developing chronic lung disease (CLD). Primary objectives are to assess effects on short term outcome (changes in need for oxygen or ventilatory support) and effects on long-term outcome. Secondary objectives are to assess changes in pulmonary mechanics and potential complications of therapy.

SEARCH STRATEGY

We used the standard search method of the Cochrane Neonatal Review Group. We used the following keywords: { or } and , limited to and limited to or . We searched MEDLINE (1966 - 1998), EMBASE (1974 - 1998) and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006). In addition, we hand searched several abstract books of national and international American and European Societies. The search of MEDLINE and of CENTRAL was last updated in March 2006.

SELECTION CRITERIA

For the purpose of this analysis, we included trials in which preterm infants with or developing chronic lung disease and at least five days of age were all randomly allocated to receive an aerosolized loop diuretic. Eligible studies needed to assess at least one of the outcome variables defined a priori for this systematic review. Primary outcome variables included need for ventilator support, chronic lung disease, mortality and other important clinical outcomes. Secondary outcome variables included pulmonary mechanics and potential complications of therapy.

DATA COLLECTION AND ANALYSIS

We used the standard method for the Cochrane Collaboration which is described in the Cochrane Collaboration Handbook. Two investigators extracted, assessed and coded separately all data for each study, using a form that was designed specifically for this review. Any disagreement was resolved by discussion. We combined parallel and cross-over trials and, whenever possible, transformed baseline and final outcome data measured on a continuous scale into change scores using Follmann's formula.

MAIN RESULTS

We identified eight studies that met selection criteria. Most studies focused on pathophysiological parameters and did not assess effects on important clinical outcomes defined in this review or the potential complications of diuretic therapy. No study assessed the amount of diuretic effectively delivered to the patient. Furosemide was the only diuretic used in the eight studies included in this review. Among preterm infants < 3 weeks of age developing CLD, not enough information is available to assess the effect of aerosolized furosemide on outcome or lung function. Among infants > 3 weeks with CLD, a single aerosolized dose of 1 mg/kg of furosemide may transiently improve pulmonary mechanics. Not enough information is available to assess the effect of chronic administration of aerosolized furosemide on oxygenation and pulmonary mechanics.

AUTHORS' CONCLUSIONS

In preterm infants > 3 weeks with CLD administration of a single dose of aerosolized furosemide improves pulmonary mechanics. In view of the lack of data from randomized trials concerning effects on important clinical outcomes, routine or sustained use of aerosolized loop diuretics in infants with (or developing) CLD cannot be recommended based on current evidence.More double-blinded randomized trials are needed (1) to analyze factors likely to affect the response to aerosolized furosemide, e.g., washout period and delivery of furosemide to distal airways, and (2) to assess the effects of chronic administration of aerosolized furosemide on mortality, O2 dependency, ventilator dependency, length of hospital stay and long-term outcome.

Aerosolized diuretics for preterm infants with (or developing) chronic lung disease

BACKGROUND

Lung disease in preterm infants is often complicated with lung edema.

OBJECTIVES

The aim of this review is to assess the risks and benefits of aerosolized diuretic administration in preterm infants with or developing chronic lung disease (CLD). Primary objectives are to assess effects on short term outcome (changes in need for oxygen or ventilatory support) and effects on long-term outcome. Secondary objectives are to assess changes in pulmonary mechanics and potential complications of therapy.

SEARCH STRATEGY

We used the standard search method of the Cochrane Neonatal Review Group. We used the following keywords: ¿<bronchopulmonary dysplasia> or <chronic lung disease>¿ and <explode diuretics>, limited to <human> and limited to <infant, newborn> or <infant>. We searched Medline (1966-1998), Embase (1974-1998) and the Cochrane Controlled Trials Register (CCTR) from the Cochrane Library (1998, Issue 4). In addition, we hand searched several abstract books of national and international American and European Societies.

SELECTION CRITERIA

We included in this analysis trials in which preterm infants with or developing chronic lung disease and at least five days of age were all randomly allocated to receive an aerosolized loop diuretic. Eligible studies needed to assess at least one of the outcome variables defined a priori for this systematic review. Primary outcome variables included important clinical outcomes, and secondary outcome variables included pulmonary mechanics and potential complications of therapy.

DATA COLLECTION AND ANALYSIS

We used the standard method for the Cochrane Collaboration which is described in the Cochrane Collaboration Handbook. Two investigators extracted, assessed and coded separately all data for each study, using a form that was designed specifically for this review. Any disagreement was resolved by discussion. We combined parallel and cross-over trials and, whenever possible, transformed baseline and final outcome data measured on a continuous scale into change scores using Follmann's formula.

MAIN RESULTS

We identified eight studies which met selection criteria. Most studies focused on pathophysiological parameters and did not assess effects on important clinical outcomes defined in this review or the potential complications of diuretic therapy. No study assessed the amount of diuretic effectively delivered to the patient. Furosemide was the only diuretic used in the eight studies included in this review. Among preterm infants < 3 weeks of age developing CLD, not enough information is available to assess the effect of aerosolized furosemide on outcome or lung function. Among infants > 3 weeks with CLD, a single aerosolized dose of 1 mg/kg of furosemide may transiently improve pulmonary mechanics. Not enough information is available to assess the effect of chronic administration of aerosolized furosemide on oxygenation and pulmonary mechanics.

REVIEWER'S CONCLUSIONS

In preterm infants > 3 weeks with CLD administration of a single dose of aerosolized furosemide improves pulmonary mechanics. In view of the lack of data from randomized trials concerning effects on important clinical outcomes, routine or sustained use of aerosolized loop diuretics in infants with (or developing) CLD cannot be recommended based on current evidence. More double-blinded randomized trials are needed (1) to analyze factors likely to affect the response to aerosolized furosemide, e.g. , washout period and delivery of furosemide to distal airways, and (2) to assess the effects of chronic administration of aerosolized furosemide on mortality, O2 dependency, ventilator dependency, length of hospital stay and long-term outcome.

Immunosuppressive and cytotoxic effects of furosemide on human peripheral blood mononuclear cells

BACKGROUND

We have previously shown that children with mild asthma have a modest improvement in their pulmonary function tests after aerosolized furosemide. The mechanism of action is not known. The observation that furosemide possesses a similar profile of protection as sodium cromoglycate and nedocromil sodium suggests that furosemide may inhibit mediator production and release.

OBJECTIVE

We studied the in vitro effects of furosemide on cytokine release from normal human peripheral blood mononuclear cells (PBMC) induced by E. coli lipopolysaccharide (LPS).

METHODS

Peripheral blood mononuclear cells were isolated by density gradient centrifugation, stimulated with LPS and incubated at 37 degrees C with varying concentrations of furosemide, hydrocortisone, sodium cromoglycate, and nedocromil sodium for 24 hours. Supernatants were extracted and study for levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-8 (IL-8). Intracellular IL-6 and TNF-alpha concentrations were also measured by cell cytometry. Cell viability was examined using XTT cell proliferation test and-measuring the release of lactate dehydrogenase (LDH).

RESULTS

There was a significant reduction in levels of TNF-alpha and IL-6 at a furosemide concentration of 0.5 x 10(-2) M and a reduction in IL-8 levels at 10(-2) M. This inhibition was comparable to that found with equivalent molar concentrations of hydrocortisone. These findings were also confirmed with measurements of intracellular IL-6 and TNF-alpha by cell cytometry. High concentration of furosemide at 10(-2) M caused significant cellular cytotoxicity.

CONCLUSION

These data suggest that furosemide may exhibit an anti-inflammatory effect. Specifically, the addition of furosemide resulted in decreased production of cytokines. This effect may be due to an immunosuppressive activity on monocytes as well as a direct cytotoxic effect at high furosemide concentrations.

Effect of furosemide on hyperpnea-induced airway obstruction, injury, and microvascular leakage

Furosemide attenuates hyperpnea-induced airway obstruction (HIAO) in asthmatic subjects via unknown mechanism(s). We studied the effect of furosemide on dry air-induced bronchoconstriction, mucosal injury, and bronchovascular hyperpermeability in a canine model of exercise-induced asthma. Peripheral airway resistance (Rp) was recorded before and after a 2-min dry-air challenge (DAC) at 2,000 ml/min. After pretreatment with aerosolized saline containing 0.75% dimethyl sulfoxide, DAC increased Rp 72 +/- 11% (SE, n = 7) above baseline; aerosolized furosemide (10(-3) M) reduced this response by approximately 50 +/- 6% (P < 0.01). To assess bronchovascular permeability, colloidal carbon was injected (1 ml/kg i.v.) 1 min before DAC, and after 1 h, the vehicle- and furosemide-treated airways were prepared for morphometric analysis. Light microscopy confirmed previous studies showing that DAC damaged the airway epithelium and enhanced bronchovascular permeability. Furosemide did not inhibit dry air-induced mucosal injury or bronchovascular hyperpermeability and in fact tended to increase airway damage and vascular leakage. This positive trend toward enhanced bronchovascular permeability in DAC canine peripheral airways is consistent with the hypothesis that furosemide inhibits HIAO in part by enhancing microvascular leakage and thus counterbalancing the evaporative water loss that occurs during hyperpnea.

The preventive effect and duration of action of two doses of inhaled furosemide on exercise-induced asthma in children

BACKGROUND

Exercise-induced asthma can be prevented by treatment with inhaled furosemide.

OBJECTIVE

In this study we evaluated the effect and duration of action of two doses (15 and 30 mg) of inhaled furosemide in prevention of exercise-induced asthma in children.

METHODS

Ten children with exercise-induced asthma (8 boys and 2 girls, aged 6 to 13 years) were included in the study. Each patient was tested with three treatment regimens (placebo, 15 mg of furosemide, and 30 mg of furosemide) in random order on 3 separate days. Patients performed exercise challenges on a treadmill at 20 minutes and 1, 2, 3, and 6 hours after each treatment. Pulmonary function, urinary output, and fluid intake were monitored.

RESULTS

Both doses of furosemide had a significantly greater protective effect than placebo, but there was no significant difference between the two doses of furosemide. The higher dose of furosemide was associated with increased urinary output and had a longer duration of action.

CONCLUSION

A 30 mg dose of furosemide is more effective for treatment of exercise-induced asthma in terms of duration but has a significant diuretic effect.

Aerosolized furosemide in wheezy infants: a negative report

We investigated the effects of 10 mg aerosolized furosemide on clinical score in 28 acutely wheezing infants (Part A) and in a second group of 20 intermittently wheezing babies on airway resistance and functional residual capacity during a symptomfree period (Part B), using a double-blind, placebo-controlled design. In both parts of the study no therapeutic effects were observed during and following aerosol inhalation of 10 mg furosemide.

Inhaled frusemide and exercise-induced bronchoconstriction in children with asthma

BACKGROUND

Nebulised frusemide has been shown to be protective against bronchoconstricting stimuli in adult asthmatic subjects and against cold air challenge in children. Animal studies suggest that inhaled frusemide may be more effective in the young.

METHODS

A double blind placebo, controlled, crossover study on the effect on exercise of pretreatment with frusemide (20 mg) from a metered dose inhaler via a large volume spacer (Volumatic) was performed in 12 asthmatic children. Exercise testing consisted of eight minutes of running on a treadmill in an environmentally controlled laboratory.

RESULTS

Deterioration in lung function was less after frusemide than after the placebo exercise tests. The mean (95% CI) maximum percentage falls in forced expiratory volume in one second (FEV1) were 14.4% (7.7 to 21.0) for placebo and 5.7% (2.3 to 9.0) for frusemide.

CONCLUSIONS

Inhaled frusemide via a metered dose inhaler reduces exercise-induced bronchoconstriction in children.

Nebulized furosemide in infants with bronchopulmonary dysplasia

The effects of 0.1 mg, 0.25 mg, 0.50 mg, and 1.0 mg of nebulized furosemide per kilogram of body weight on pulmonary functions were studied in eight preterm infants with bronchopulmonary dysplasia who were supported by mechanical ventilation. Doses of 1 mg/kg significantly improved lung compliance (51% at 2 hours after nebulization), pulmonary resistance (28% at 1 hour), and tidal volume (43% at 1 hour), starting as early as 30 minutes after the dose; the effect lasted for at least 4 hours in many of the infants and was not associated with diuresis or renal side effects.

Reversal of bronchial obstruction in children with mild stable asthma by aerosolized furosemide

Aerosolized furosemide has been shown to prevent the worsening of different variables in pulmonary function testing, following exercise or bronchial provocation with numerous agents. To investigate if aerosolized furosemide has a bronchodilator effect, we performed two prospective, randomized, placebo-controlled, double-blinded and crossover studies of four aerosol regimens in children with mild chronic asthma. In a pilot study examining three different doses of furosemide in 11 children, the dose of 1.0 mg/kg resulted in a mean maximum increase of 30.0 +/- 6.8% in forced expiratory flow between 25 and 75% vital capacity (FEF25-75), compared with a 3.1 +/- 6.8% increase after aerosolized normal saline. The effect was observed after 10 minutes with a mean percent change of 17.7 +/- 1.7% from baseline, that persisted to 30 minutes (19.3 +/- 3.7%) and was significantly greater than that seen following aerosolized placebo (1.4 +/- 2.9% and 0.7 +/- 3.4%, respectively; P < 0.05). We then compared the effect of furosemide with that of aerosolized albuterol (0.15 mg/kg) in 18 patients. There was no statistically significant difference in the improvement observed in forced expiratory volume in 1 second (FEV1) for albuterol (15.0 +/- 2.7%) compared with furosemide (12.1 +/- 2.9%) or in FEF25-75 (42.9 +/- 9.0% versus 26.3 +/- 6.7%). The addition of albuterol to furosemide resulted in a 17.2 +/- 5.9% increase in FEV1 and a 51.1 +/- 13.9% increase in FEF25-75. Our results indicate that aerosolized furosemide has a bronchodilator effect in children with mild stable asthma.

Evaluation of cold air challenge data in a population sample using a model of bronchial hyperreactivity and disposition to bronchial obstruction

To explore the role of bronchial hyperreactivity and obstruction after cold air challenge, data from a cross-sectional study of more than 7,000 10-year-old children were used. Current knowledge of hyperreactivity is primarily based on pharmacological provocation tests with variable prechallenge flow rates and their decrease relative to baseline. Using forced expiratory volume (FEV) in 1 sec values before and after cold air challenge, however, it is possible to define a subsample of children with predominant hyperreactivity and a subsample with predominant obstruction after challenge. The prevalence of respiratory symptoms and the diagnoses in the two subsamples were compared. The analysis showed that children with bronchial obstruction have nearly the same frequency of respiratory symptoms as those with bronchial hyperreactivity. A combined model of bronchial obstruction and hyperreactivity was, therefore, more predictive of symptoms than a model of hyperreactivity alone.