Hypoxaemia after nebulised salbutamol in wheezy infants: the importance of aerosol acidity

A prospective randomized controlled blinded study of three bronchodilators in infants with respiratory syncytial virus bronchiolitis on mechanical ventilation

OBJECTIVE

To study patients with respiratory syncytial virus bronchiolitis in respiratory failure to make specific measurements reflecting airway resistance before and after treatment with commonly used agents. We hypothesized that racemic epinephrine would decrease airways resistance more effectively than levalbuterol, and levalbuterol would decrease airways resistance more effectively than racemic albuterol. Normal saline was used as a control.

DESIGN

Prospective, randomized, controlled, blinded study.

SETTING

Tertiary Pediatric Intensive Care Unit in a University affiliated hospital in the northeastern United States.

PATIENTS

Twenty-two patients with respiratory syncytial virus bronchiolitis and in respiratory failure were enrolled. All were intubated and ventilated in a volume control mode and sedated.

INTERVENTIONS

In a randomized, blinded fashion patients were given four agents: norepinephrine, levalbuterol, racemic albuterol, and normal saline at 6 hr intervals.

MEASUREMENTS

As indicators of bronchodilation, peak inspiratory pressure and inspiratory respiratory system resistance were measured before and 20 mins after each agent was given. Thus, each patient acted as his/her own control.

MAIN RESULTS

There were small but statistically significant decreases in peak inspiratory pressure after racemic epinephrine treatment, levalbuterol, and racemic albuterol. There was no change in peak inspiratory pressure after inhaled normal saline. Inspiratory respiratory system resistance fell significantly after all treatments, including saline. Heart rate rose significantly after inhaled bronchodilator treatments (p < 0.05 for all treatments).

CONCLUSIONS

Similar statistically significant bronchodilation occurred after all three bronchodilators as indicated by a decrease in peak inspiratory pressure and respiratory system resistance, but these changes were small and probably clinically insignificant. However, side effects of bronchodilators, such as tachycardia, also occurred, and these may be clinically significant. Thus the benefit of bronchodilator treatment in these patients is small, does not differ among the drugs we studied and of questionable value.

Additive effects of dexamethasone in nebulized salbutamol or L-epinephrine treated infants with acute bronchiolitis

BACKGROUND

Although it is the most common lower respiratory infection of infancy, the optimal treatment for acute bronchiolitis is still controversial. The aim of this study was to compare the early and late effects of nebulized L-epinephrine (EPI) and intramuscular dexamethasone (DEX) combination therapy with nebulized salbutamol (SAL) and dexamethasone combination and bronchodilators alone in outpatients with acute bronchiolitis.

METHODS

A total of 69 infants aged 2-21 months who were admitted to the Pediatrics Department of the Faculty of Medicine, Mersin University, with acute bronchiolitis were included in a randomized, placebo-controlled, prospective trial study. Patients were assigned to receive either nebulized L-epinephrine (3 mg) or salbutamol (0.15 mg/kg) and 15 min later, either dexamethasone 0.6 mg/kg or placebo (PLA), intramuscularly, in a double-blind randomized fashion. The study groups were: epinephrine + dexamethasone group (group 1, n=23), salbutamol + dexamethasone group (group 2, n=23), epinephrine + placebo group (group 3, n=11), and salbutamol + placebo group (group 4, n=12). The outcome measures were heart rate, respiratory rate and Respiratory Distress Assessment Instrument (RDAI) score determined at 30, 60, 90 and 120 min, 24 h, and 5 days after the first therapy. Patients were then followed-up during the subsequent 2 months for the prevalance of respiratory complaints regarding bronchial hyperreactivity.

RESULTS

There were no significant differences between the outcome variables of the four groups within the first 120 min and at 24 hours, or between the rates of requirement of a second dose of the same bronchodilator. However, fifth day RDAI score values of both DEX groups were significantly lower than that of SAL + PLA group (P=0.000 and P=0.01, respectively). The fifth day score value of group 1 was also significantly better than that value of EPI + PLA group but not different from group 2.

CONCLUSIONS

A single dose of intramuscular dexamethasone added to nebulized L-epinephrine, or salbutamol therapies resulted in better outcome measures than bronchodilators alone in the late phase (fifth day) of mild to moderate degree bronchiolitis attack. However, effects of EPI + DEX combination was not different from SAL + DEX combination.

Inhaled antibiotic therapy: What drug? What dose? What regimen? What formulation?

Early studies of the use of antibiotics in patients with cystic fibrosis suggested that they would be of benefit in preventing or reducing infection by Pseudomonas aeruginosa. In seeking to optimize treatment, factors such as the drug used, the dose, the regimen and the formulation must be considered. Aminoglycosides are ideal for aerosolization because they have a long post-antibiotic effect and have an acceptable taste. Tobramycin is one of the aminoglycosides with the lowest systemic toxicity, which enables the aerosol delivery of doses high enough to overcome the antagonistic effects of the sputum. The most dramatic benefits from inhaled tobramycin have been shown to occur in the first 2-4 weeks of administration. Continual administration for longer periods can result in the development of resistance and loss of the improvement in lung function. However, this resistance is transient, and susceptibility to tobramycin returns after a short drug holiday. Optimal drug administration therefore consists of a 4-week on, 4-week off cycle. Such a cycle also helps to maintain patient compliance. Successful drug delivery also depends upon a formulation that does not provoke bronchoconstriction, which demands a formulation that is both preservative free, and osmotically and pH balanced. This research has enabled the development of a novel formulation of tobramycin optimized for use as an inhalation therapy in cystic fibrosis.

Short acting beta agonists for recurrent wheeze in children under 2 years of age

BACKGROUND

Wheeze is a common symptom in infancy and is a common cause for both primary care consultations and hospital admission. Beta2-adrenoceptor agonists (b2-agonists) are the most frequently used as bronchodilator but their efficacy is questionable.

OBJECTIVES

To determine the effectiveness of b2-agonist for the treatment of infants with recurrent and persistent wheeze.

SEARCH STRATEGY

Relevant trials were identified using the Cochrane Airways Group database (CENTRAL), Medline and Pubmed. The database search used the following terms: Wheeze or asthma and Infant or Child and Short acting beta-agonist or Salbutamol (variants), Albuterol, Terbutaline (variants), Orciprenaline, Fenoterol

SELECTION CRITERIA

Randomised controlled trials comparing the effect of b2-agonist against placebo in children under 2 years of age who had had two or more previous episodes of wheeze, not related to another form of chronic lung disease.

DATA COLLECTION AND ANALYSIS

Eight studies met the criteria for inclusion in this meta-analysis. The studies investigated patients in three settings: at home (3 studies), in hospital (2 studies) and in the pulmonary function laboratory (3 studies). The main outcome measure was change in respiratory rate except for community based studies where symptom scores were used.

MAIN RESULTS

The studies were markedly heterogeneous and between study comparisons were limited. Improvement in respiratory rate, symptom score and oxygen saturation were noted in one study in the emergency department following two salbutamol nebulisers but this had no impact on hospital admission. There was a reduction in bronchial reactivity following salbutamol. There was no significant benefit from taking regular inhaled salbutamol on symptom scores recorded at home.

REVIEWER'S CONCLUSIONS

There is no clear benefit of using b2-agonists in the management of recurrent wheeze in the first two years of life although there is conflicting evidence. At present, further studies should only be performed if the patient group can be clearly defined and there is a suitable outcome parameter capable of measuring a response.

Effect of nebulizer type and antibiotic concentration on device performance

We compared the performance of selected ultrasonic and jet nebulizers when aerosolizing several antibiotic formulations to determine optimum combinations for delivery of a respirable antibiotic aerosol. Three ultrasonic devices were tested: the UltraNeb 99/100, the UltraAIR and the Aerosonic. The reusable jet nebulizers were the Dura ProNeb, Pari-LL and the Sidestream. The six disposable jet nebulizers were Marquest Acorn II, Hudson T Updraft II, Baxter MistyNeb, Pari-LC, Pari IS-2, and a disposable Sidestream. Each jet was tested with four compressors: a DeVilbiss AP-50, a Pulmo-Aide, a DuraNeb and a PariMaster. All nebulizing systems were initially tested with normal saline. From the initial data, six jet nebulizers and one ultrasonic device were tested with varying concentrations of tobramycin, gentamicin, ceftazidime, ciprofloxacin and colistin. Output was assessed by measuring volume (milliliters per minute), and amount of drug (milligrams per minute) nebulized. We then measured mean particle size of the antibiotic aerosol with seven jet nebulizers and two different compressors, Pulmo-Aide and PariMaster, and two ultrasonic devices. The rate of nebulization of saline and antibiotic solutions (milliliters per minute) was greater with the ultrasonic device(s) than all jet nebulizer systems tested. Increasing the reservoir antibiotic concentration increased the drug output (milligrams per minute) with the jet nebulizers to a maximum, followed by decreasing output. When antibiotic concentrations were increased the output decreased more precipitously with the ultrasonic devices than with the jet nebulizers. At the highest antibiotic concentrations tested, the ultrasonic devices had the lowest output. Particle size distribution was most dependent on the specific jet device, with particle size distribution less affected by a specific antibiotic or its concentration. Higher reservoir concentrations can be utilized for increasing output of respirable antibiotic aerosols by jet nebulizers. We conclude that antibiotic output is dependent upon both the nebulizing system and the reservoir concentration of antibiotic.

A randomized trial comparing the efficacy of epinephrine with salbutamol in the treatment of acute bronchiolitis

This randomized, double-blind trial compared the efficacy of nebulized epinephrine with salbutamol in the treatment of infants with acute bronchiolitis. The mean percent oxygen saturation at 60 minutes was significantly higher in the epinephrine group. Thirty-three percent of the patients in epinephrine group were admitted to the hospital compared with 81% of the salbutamol group (p = 0.003). We conclude that nebulized epinephrine is more efficacious than salbutamol for infants with acute bronchiolitis seen in an emergency department.

[Comparative study of nebulized sambutol against placebo in the acute phase of bronchiolitis in 33 infants aged 1 to 6 months]

BACKGROUND

The therapeutic role of bronchodilators in bronchiolitis remains controversial. The aim of this study is to evaluate the safety and the clinical response to nebulized salbutamol in infants with mild acute bronchiolitis.

PATIENTS AND METHODS

Thirty-three infants, aged 1 month to 5 months and 22 days (mean: 92.4 days) were included in the study. Patients received either nebulized salbutamol (0.15 mg/kg per dose: 16 infants) or a placebo (normal saline aerosol: 17 infants), delivered by an oxygen propellent, three times at intervals of 1 hour, as part of a double-blind randomized trial. Effect of treatment was evaluated by measuring respiratory and heart rate, clinical scores based on the degree of retraction and wheezing, and oxygen saturation. Clinical assessment was repeated 30 minutes after each nebulization. A nasopharyngeal swab was obtained for detection of respiratory syncytial virus (VRS) antigens by immunofluorescence assay in all patients.

RESULTS

Patients in the salbutamol group exhibited significantly greater improvement in respiratory rate (P = 0.01), accessory muscle score (P < 0.001) and wheezing score (P < 0.001). There was no significant difference in oxygen saturation between both groups. Infants treated with salbutamol exhibited a non-significant increase in heart rate after the three sprays; no other adverse effects were noted. VRS was identified in 78% of the children tested.

CONCLUSIONS

Salbutamol is safe and effective in relieving the respiratory distress of young infants with acute bronchiolitis. Our study confirms previous observations that infants younger than six months of age respond as well as older children when given three doses of nebulized salbutamol. Responders could not be differentiated from non responders by personal or family histories of atopy and VRS isolation. A longitudinal study could establish a correlation between response to bronchodilator therapy and later development of asthma.

Oral versus nebulized albuterol in the management of bronchiolitis in Egypt

The efficacy of albuterol in the management of infants with first-time wheezing is controversial. This double-blind, placebo-controlled trial involved 128 Egyptian infants with first-time wheezing (mean age 5.9 months) who were randomly separated into four equivalent therapy groups: nebulized albuterol, nebulized saline solution, orally administered albuterol, and orally administered placebo. The nebulized therapy groups received two treatments 30 minutes apart; the oral therapy groups received one treatment. In addition, 41 infants with recurrent wheezing comprised an open-label control group who received two albuterol nebulizations. Chest radiographs, leukocyte counts, blood culture specimens, and nasal aspirate for viral antigen detection were obtained to confirm the clinical diagnosis of viral bronchiolitis. Respiratory and heart rates, clinical score, and oxygen saturation were recorded at baseline and 30 and 60 minutes after treatment. There was no difference among the four randomized groups in any of the outcomes except for an increase in heart rate of 10 beats/min in the nebulized albuterol group compared with a decrease in heart rate of 8 beats/min in the oral placebo group. No differences in the need for additional treatment were observed. Nebulized albuterol significantly improved the clinical score and reduced the respiratory rate of those with recurrent wheezing relative to those in the randomized groups. We conclude that nebulized albuterol is effective in the treatment of infants with recurrent wheezing, but there was no demonstrable efficacy of orally administered or nebulized albuterol in relieving the respiratory distress of infants with bronchiolitis in Egypt.

Management of asthma in pre-school children

The management of asthma in pre-school children often presents physicians with challenging problems. This article addresses the diagnostic criteria by which the diagnosis may be made, discusses the prognosis of untreated asthma and states the principles underlying the treatment of asthma in this age group. The management according to a stepwise protocol is discussed with reference both to maintenance therapy, and the treatment of acute severe asthma. The methods by which appropriate medication may be delivered are also described.

Inhaled frusemide against cold air induced bronchoconstriction in asthmatic children

Inhaled frusemide prevents bronchoconstriction in asthmatic adults induced by various triggers. To determine if frusemide provides similar protection in children, whether this is age dependent and equally effective for central and peripheral airways, we performed a double blind, placebo controlled, randomised, crossover study on the effect of inhaled frusemide on lung function changes induced by cold air challenge in 21 asthmatic children. In addition, we measured diuresis before and after inhalation. Bronchodilatation after frusemide was not observed. However, deterioration in lung function after frusemide, compared with placebo, was significantly diminished: forced expiratory volume in one second (FEV1) was -5.7% v -11.5%, peak expiratory flow (PEF) -7.7% v -23.3%, maximum expiratory flow at 50% of vital capacity (MEF50VC) -16.0% v -35.2%, and at 60% of total lung capacity (MEF60TLC) -32.4% v -61.6%, and specific airways conduction -42.0% v -57.7%, respectively. This effect was not age dependent. Diuresis was significantly increased from a mean (SEM) of 198 (34) ml/3 hours before inhaled frusemide to 379 (62) ml/3 hours after nebulisation. We conclude that inhaled frusemide prevents cold air induced bronchoconstriction in asthmatic children and that increased diuresis can be expected with a dose as low as 28 mg of frusemide given by nebuliser.