Ipratropium bromide for symptomatic preterm infants

Advances in treating bronchopulmonary dysplasia

Introduction: Bronchopulmonary dysplasia (BPD) is a common long-term adverse complication of very premature delivery. Affected infants can suffer chronic respiratory morbidities including lung function abnormalities and reduced exercise capacity even as young adults. Many studies have investigated possible preventative strategies; however, it is equally important to identify optimum management strategies for infants with evolving or established BPD. Areas covered: Respiratory support modalities and established and novel pharmacological treatments. Expert opinion: Respiratory support modalities including proportional assist ventilation and neurally adjusted ventilatory assist are associated with short term improvements in oxygenation indices. Such modalities need to be investigated in appropriate RCTs. Many pharmacological treatments are routinely used with a limited evidence base, for example diuretics. Stem cell therapies in small case series are associated with promising results. More research is required before it is possible to determine if such therapies should be investigated in large RCTs with long-term outcomes.

Drug therapies in bronchopulmonary dysplasia: debunking the myths

Bronchopulmonary dysplasia (BPD), also known as chronic lung disease (CLD), is one of the most challenging complications in premature infants. The incidence of BPD has been increasing over the past two decades in parallel with an improvement in the survival of this population. Furthermore, the clinical characteristics and the natural history of infants affected by BPD have changed considerably, and newer definitions to clarify the term 'BPD' have also evolved since its first description more than four decades ago. Several drug therapies have also evolved, either to manage these infants' respiratory distress syndrome with an aim to prevent BPD or to manage the established condition. Although there is good evidence to support the 'routine' use of some therapies, many other therapies currently used in relation to BPD remain individual- or institution-specific, depending on beliefs and myths that we have adopted. In this article, we discuss the importance of defining BPD more objectively and the support--or lack thereof--for the drug therapies used in relation to BPD.

Adjunctive therapies in chronic lung disease: examining the evidence

Chronic lung disease (CLD) or bronchopulmonary dysplasia (BPD) is one of the most common long-term complications in very premature infants. The incidence of CLD has been increasing over the past two decades in parallel with an improvement in the survival of this population. We have witnessed a revolution in the therapies that are used, either to manage these infants' respiratory distress syndrome (RDS) with an aim to prevent CLD or to manage the established condition. Several devices and strategies have been developed to provide respiratory support with minimal risk of lung injuries. Multiple adjunctive agents have also been used either to reduce the risk of CLD or to mitigate its course. There is considerable evidence supporting the use of exogenous surfactant, but unfortunately many other therapies currently used for CLD, either preventative or as a treatment, are based on very little or no evidence. The gold standard to assess a given therapy is the randomised controlled trial (RCT), designed to look at clinically meaningful outcomes and long-term safety. In this context, we discuss the support - or lack thereof - for the adjunctive therapies used in relation to CLD. Many of the therapies have been examined as systematic reviews by the Cochrane Neonatal Review Group. These reviews are noted in the references and can be easily accessed at the following website sponsored by the National Institute of Child Health and Human Development: www.nichd.nih.gov/cochrane/default.cfm.

Evidence-based use of adjunctive therapies to ventilation

Respiratory distress is the most common reason for admission to newborn intensive care units. Over the past two decades, we have witnessed a revolution in the therapies that are used to manage neonates who have pulmonary disorders. Multiple adjunctive agents have also been used in an attempt to mitigate the course of neonatal lung disease. The disorders we discuss include respiratory distress syndrome, chronic lung disease/bronchopulmonary dysplasia, persistent pulmonary hypertension of the newborn, meconium aspiration syndrome, and transient tachypnea of the newborn. We review the evidence that either supports or refutes the use of adjunctive therapies for these disorders.

Frequent wheeze at follow up of very preterm infants: which factors are predictive?

OBJECTIVE

To determine if chest radiograph appearance at 28 days or 36 weeks postmenstrual age (PMA) can predict recurrent wheeze or cough at follow up in prematurely born infants more effectively than readily available clinical data.

DESIGN

Chest radiographs of infants entered into the UKOS trial, who had had a chest radiograph at 28 days and 36 weeks PMA and completed six months of follow up, were assessed for the presence of fibrosis, interstitial shadows, cystic elements, and hyperinflation. At 6 months of corrected age, the occurrence and frequency of wheeze and cough since discharge were determined using a symptom questionnaire.

PATIENTS

A total of 185 infants with a median gestational age of 26 (range 23-28) weeks.

RESULTS

Thirty seven infants wheezed more than once a week, compared with the rest of the cohort. These infants had significantly higher chest radiograph scores at 28 days (p = 0.020) and 36 weeks PMA (p = 0.005), with significantly higher scores at 28 days for fibrosis (p = 0.017) and at 36 weeks PMA for fibrosis (p = 0.001) and cystic elements (p = 0.0007). They had also been ventilated for longer (p = 0.013). Forty four infants coughed more than once a week; they did not differ significantly from the rest of the cohort. An abnormal chest radiograph score at 36 weeks PMA had the largest area under the receiver operator characteristic curve with regard to prediction of frequent wheeze.

CONCLUSION

An abnormal chest radiograph appearance at 36 weeks PMA predicts frequent wheeze at follow up and appears to be a better predictor than readily available clinical data.

Measuring respiratory outcome

Chronic respiratory morbidity is a common outcome of very premature birth. Infants who are chronically oxygen dependent with an abnormal chest radiograph are described as suffering from chronic lung disease (CLD), and those with the worst abnormalities diagnosed as having bronchopulmonary dysplasia. CLD infants are very likely to be readmitted to hospital during infancy, particularly during a respiratory syncytial virus (RSV) epidemic. Very low birthweight, prematurity and CLD are associated with recurrent respiratory symptoms and lung function abnormalities during the preschool years. These problems are detected even in adolescents who were chronically oxygen dependent after premature birth. Further research to identify effective preventative strategies is urgently required.

Efficacy of bronchodilators administered by nebulizers versus spacer devices in infants with acute wheezing

The aim of this study was to compare the response of infants with acute wheezing to treatments with inhaled terbutaline when administered by nebulizer or by metered-dose inhaler and spacer device (MDI-spacer). Thirty-four infants between the ages of 1 and 24 months who were seen in our emergency department for acute wheezing were studied in a double-blind, randomized trial. The participants received two treatments of terbutaline at 20-min intervals, either by a nebulizer (2 mg/dose in 2.8 mL of 0.9% saline solution) or by an MDI-spacer device (0.5 mg/dose). The outcome measure was a clinical score, based on respiratory rate, degree of wheezing, retractions, degree of cyanosis, color, and pulse oximetry data measured before treatment, 20 min after the first treatment, and again 20 min after the second treatment. There was no difference in the rate of improvement in the clinical score between infants who received terbutaline by nebulizer and those who received it by MDI-spacer. We conclude that MDI-spacers and nebulizers are equally effective means of delivering beta-2 agonists to infants and small children with acute wheezing.

Inhaled nedocromil sodium in symptomatic young children born prematurely

The efficacy of a non-steroidal anti-inflammatory agent (nedocromil sodium, NS) has been assessed in young children born prematurely who had recurrent respiratory symptoms at follow-up. In a randomized, double-blind cross-over trial, either two puffs of NS (2 mg puff-1) or placebo were administered three times a day via a spacer device and face mask. Fifteen children, median gestational age 27 weeks, birthweight 1100 g and postnatal age 12 months were studied. The symptom score was lower in the last 2 weeks of the active period (median score 26) compared to the run-in period (median score 55) and the last 2 weeks of the placebo period (median score 50), P < 0.01. The maximum possible symptom score for a 2-week period was 210. Compared to the run-in period, children required fewer days of bronchodilator therapy in the last 2 weeks of the active treatment (P < 0.01), but not in the placebo period. Although results of functional residual capacity (FRC) measurements were available on only 13 of the 15 children, these did demonstrate a significant change in FRC over the active, but not the placebo, period. These data suggest that NS is a useful prophylactic agent for children born prematurely and who are symptomatic at follow-up.

Respiratory morbidity in preschool children born prematurely. Relationship to adverse neonatal events

Respiratory morbidity, recurrent cough and/or wheeze and lung function abnormalities are common even outside infancy in preschool children born prematurely. Throughout the first 5 years of life, adverse neonatal events such as immaturity at birth and a requirement for prolonged respiratory support are significantly associated with positive symptom status. In the older preschool child, however, there is some evidence to suggest that other factors, such as a family history of atopy, may be equally important. The development of recurrent symptoms even at 4 years of age can be predicted accurately from the results of lung function measurements made in infancy, and hopefully such data will facilitate the introduction of effective intervention strategies. Lung function abnormalities are more marked in symptomatic patients and, in older children, seem to reflect increased airway responsiveness rather than having a significant relationship to adverse neonatal events. The hospital readmission rate for respiratory disorders, however, is certainly adversely affected by extremely low birthweight and neonatal chronic lung disease, as well as current symptom status. These data highlight that strategies to reduce extremely premature delivery and its consequences should favourably influence respiratory morbidity in preschool children.

Use of anticholinergic bronchodilation in children

Ipratropium bromide is a quaternary ammonium anticholinergic bronchodilator with minimal systemic absorption across the blood-airway barrier. Ipratropium bromide has become primary therapy for the treatment of adults with chronic bronchitis, but its use in children has been limited. Ipratropium bromide can be safely used in the management of acute bronchiolitis, recognizing that most infants do not appear to respond to any bronchodilator medication. When used with a beta-agonist bronchodilator for the therapy of acute childhood asthma, ipratropium bromide appears to provide bronchodilation beyond that achieved by either agent used alone. There are insufficient published data to determine the appropriate use if ipratropium bromide in infants with bronchopulmonary dysplasia, although many of those symptomatic after the age of 6 months seem to benefit from either ipratropium bromide or beta-agonists. As ipratropium bromide has no intrinsic anti-inflammatory properties, its role in the chronic therapy of asthma and related disorders is still unclear.

Relationship between lung function results in the first year of life and respiratory morbidity in early childhood in patients born prematurely

The relationship between lung function results at 6 months and 1 year of age to respiratory symptoms in the first 3 years of life in prematurely born population has been determined. In 88 infants (median gestational age, 29 weeks) thoracic gas volume (TGV) and airway resistance (R(aw)) was measured and specific conductance (SGaw) calculated at 6 months and 1 year of age. During 3 years of prospective follow-up neither TGV measured at either 6 months or 1 year, nor R(aw) and SGaw at 6 months, differed significantly between infants who were asymptomatic or symptomatic. At 1 year, however, R(aw) and SGaw were significantly higher and lower respectively in patients who were symptomatic than in those who were asymptomatic in any of the 3 years. An elevated R(aw) (> or = 50 cmH2O/L/s) measured at 1 year, but not at 6 months, was associated with a significant relative risk of symptoms in the first, second, and third year of life. We conclude that in prematurely born patients an abnormal airway resistance at 1 year predicts symptoms in early childhood.

Comparison of the effects on lung function of two methods of bronchodilator administration

The aim of this study was to assess if administration of bronchodilator via a metered dose inhaler (MDI), rather than by a nebulizer, avoided the early paradoxical deterioration in lung function but, resulted in equally effective late bronchodilation. Fifteen children were studied at a median postnatal age of 9 months (range 9-18), all had been born prematurely at a median gestational age of 27 weeks (range 23-31). Lung function was measured by plethysmography before and 10 min after normal saline and 5 and 15 min after salbutamol given via an MDI and a nebulizer in random order. At 5 min, compared to baseline values, airways resistance (RAW) deteriorated by 16% after nebulized salbutamol but improved by 3% following salbutamol by the MDI (P < 0.03). At 15 min RAW improved by 14% following nebulized salbutamol and 15% after salbutamol via the MDI, there was no significant difference in the magnitude of bronchodilation between the two methods of administration. Our results therefore suggest, that as the early paradoxical deterioration in lung function is usually avoided by administering salbutamol via an MDI, this should be the preferred method of administration.

The effect of sodium cromoglycate on upper and lower respiratory symptoms in children born prematurely

The aims of this study were to assess whether sodium cromoglycate (SCG) was an effective prophylaxis against both upper and lower respiratory tract signs and to determine factors which affected the site and magnitude of the response to SCG. Sixteen children born prematurely were entered into a randomised placebo-controlled trial at 15 months of age (range 4-31 months). The patients received, in random order, either 3 weeks' treatment with SCG (5 mg) or placebo, both given four times a day by inhalation via a spacer device. Parents were asked to record the occurrence and severity of their child's upper respiratory tract signs; sneezing and runny nose and lower respiratory tract signs; day and night time cough and wheeze. During the active compared to the placebo period there was an overall reduction of 47% and 53% in upper and lower respiratory tract signs, respectively. The magnitude of response to SCG as assessed by either the change in upper or lower respiratory tract signs was not significantly related to the patient's gestational or postnatal age, the occurrence of neonatal chronic lung disease, family history of atopy or the order in which the therapy was administered. We conclude that inhaled SCG may be a useful prophylaxis for both upper and lower respiratory tract signs for children born prematurely and less than 3 years of age.

Randomised trial of inhaled steroids in preterm infants with respiratory symptoms at follow up

BACKGROUND

Preterm infants often suffer from recurrent respiratory symptoms at follow up. Although these infants are responsive to treatment with bronchodilators some continue to wheeze or cough despite treatment. In a randomised double blind placebo controlled trial, the ability of inhaled steroids to reduce recurrent respiratory symptoms and the requirement for bronchodilator treatment in preterm infants less than two years of age has been assessed.

METHODS

Eighteen premature infants with mean gestational age 28 weeks and postnatal age 10.5 months were recruited. The study consisted of two six week treatment periods separated by a two week washout period. The infants received either 200 micrograms of beclomethasone dipropionate or placebo as one puff twice daily from an inhaler, through a spacer and a face mask. Parents kept a daily record of their infants' respiratory tract symptoms (wheeze and cough) and use of bronchodilators. Functional residual capacity (FRC) was measured at the beginning and end of each six week period.

RESULTS

The symptom score was reduced by 37% in the active compared with the placebo period. During the active period the infants had a mean of 28 bronchodilator free days, compared with 22 days in the placebo period. The FRC improved significantly in the active but not the placebo period.

CONCLUSION

Regular dosage with beclomethasone by inhalation is a useful treatment for preterm infants with respiratory symptoms.

Persistence of respiratory symptoms into the second year of life: predictive factors in infants born preterm

Preterm infants frequently suffer from recurrent respiratory symptoms in the first year of life. Our aims were to assess if such respiratory morbidity persisted beyond the first year and to define the predictive factors. One hundred and seventeen infants (median gestational age 29 weeks) were followed prospectively for two years. Thirty-eight infants had symptoms only in the first year (group A) and in a further 20 infants, symptoms were present in both years (group B). Comparison of these two groups revealed no significant difference in birth weight or gestational age, but the duration of ventilation and increased inspired oxygen concentration were significantly longer in group B. Significantly more infants in group B had had an air leak in the neonatal period, and airways resistance at six months of age was also significantly higher in group B. We conclude that infants with severe neonatal respiratory distress are likely to have persisting respiratory morbidity and that respiratory function measurements at six months of age provide the most accurate predictor of chronic respiratory symptoms.

Inhaled sodium cromoglycate for pre-term children with respiratory symptoms at follow-up

Children born prematurely frequently have recurrent respiratory symptoms at follow-up and benefit from bronchodilator therapy. We have assessed if regular inhaled sodium cromoglycate would reduce this respiratory morbidity and need for bronchodilator therapy. Sixteen symptomatic children (median gestational age 29 weeks, post-natal age 15 months) were entered into a randomized double-blind, placebo-controlled trial. In two 3-week periods, the patients received either placebo or sodium cromoglycate (5 mg) as one puff q.d.s. from an inhaler via a coffee cup. Parents recorded their child's symptoms and need for bronchodilator therapy throughout and lung function was assessed by measurement of functional residual capacity (FRC) at the beginning and end of each 3-week period. The symptom score was reduced by 49% in the active compared to the placebo period (P less than 0.01) and bronchodilator was taken on a mean of 2.9 days per infant in the active period compared to 7.9 days in the placebo period (P less than 0.01). There was a significant improvement in FRC in ten of 16 patients over the active period but only in two infants over the placebo period (P less than 0.01). We conclude regular inhaled sodium cromoglycate is useful prophylaxis for symptomatic pre-term children.

Paradoxical response to nebulized ipratropium bromide in pre-term infants asymptomatic at follow-up

Lung function measurements were performed before and after bronchodilator, nebulized ipratropium bromide (10 micrograms kg-1), in 20 pre-term infants [median gestational age 28 weeks (range 23-32 weeks) at a median postnatal age of 10 months (range 6-16 months)]. Eight of the infants had recurrent respiratory symptoms. Thoracic gas volume (TGV) and airways resistance (Raw) were measured by a plethysmographic technique and functional residual capacity (FRC) by a helium gas dilution technique. There was no significant change in either TGV or FRC following bronchodilator in the symptomatic and asymptomatic infants. Nebulized bronchodilator resulted in a significant improvement in Raw amongst the symptomatic infants (P less than 0.05), but a paradoxical response, that is, a deterioration (P less than 0.05) in Raw amongst the asymptomatic infants. In three asymptomatic infants, lung function measurements were repeated before and after nebulized saline and a similar deterioration in Raw was noted. We conclude the demonstration of respiratory symptoms at follow-up is useful in predicting infants who would have a beneficial response to nebulized ipratropium bromide.