Inhaled bronchodilators for the prevention and treatment of chronic lung disease in preterm infants

BACKGROUND

Chronic lung disease (CLD) occurs frequently in preterm infants and is associated with respiratory morbidity. Bronchodilators have the potential effect of dilating small airways with muscle hypertrophy. Increased compliance and tidal volume, and decreased airway resistance, have been documented with the use of bronchodilators in infants with CLD. Therefore, bronchodilators are widely considered to have a role in the prevention and treatment of CLD, but there remains uncertainty as to whether they improve clinical outcomes. This is an update of the 2016 Cochrane review.

OBJECTIVES

To determine the effect of inhaled bronchodilators given as prophylaxis or as treatment for chronic lung disease (CLD) on mortality and other complications of preterm birth in infants at risk for or identified as having CLD.

SEARCH METHODS

An Information Specialist searched CENTRAL, MEDLINE, Embase, CINAHL and three trials registers from 2016 to May 2023. In addition, the review authors undertook reference checking, citation searching and contact with trial authors to identify additional studies.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials involving preterm infants less than 32 weeks old that compared bronchodilators to no intervention or placebo. CLD was defined as oxygen dependency at 28 days of life or at 36 weeks' postmenstrual age. Initiation of bronchodilator therapy for the prevention of CLD had to occur within two weeks of birth. Treatment of infants with CLD had to be initiated before discharge from the neonatal unit. The intervention had to include administration of a bronchodilator by nebulisation or metered dose inhaler. The comparator was no intervention or placebo.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Critical outcomes included: mortality within the trial period; CLD (defined as oxygen dependency at 28 days of life or at 36 weeks' postmenstrual age); adverse effects of bronchodilators, including hypokalaemia (low potassium levels in the blood), tachycardia, cardiac arrhythmia, tremor, hypertension and hyperglycaemia (high blood sugar); and pneumothorax. We used the GRADE approach to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included two randomised controlled trials in this review update. Only one trial provided useable outcome data. This trial was conducted in six neonatal intensive care units in France and Portugal, and involved 173 participants with a gestational age of less than 31 weeks. The infants in the intervention group received salbutamol for the prevention of CLD. The evidence suggests that salbutamol may result in little to no difference in mortality (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.50 to 2.31; risk difference (RD) 0.01, 95% CI -0.09 to 0.11; low-certainty evidence) or CLD at 28 days (RR 1.03, 95% CI 0.78 to 1.37; RD 0.02, 95% CI -0.13 to 0.17; low-certainty evidence), when compared to placebo. The evidence is very uncertain about the effect of salbutamol on pneumothorax. The one trial with usable data reported that there were no relevant differences between groups, without providing the number of events (very low-certainty evidence). Investigators in this study did not report if side effects occurred. We found no eligible trials that evaluated the use of bronchodilator therapy for the treatment of infants with CLD. We identified no ongoing studies.

AUTHORS' CONCLUSIONS

Low-certainty evidence from one trial showed that inhaled bronchodilator prophylaxis may result in little or no difference in the incidence of mortality or CLD in preterm infants, when compared to placebo. The evidence is very uncertain about the effect of salbutamol on pneumothorax, and neither included study reported on the incidence of serious adverse effects. We identified no trials that studied the use of bronchodilator therapy for the treatment of CLD. Additional clinical trials are necessary to assess the role of bronchodilator agents in the prophylaxis or treatment of CLD. Researchers studying the effects of inhaled bronchodilators in preterm infants should include relevant clinical outcomes in addition to pulmonary mechanical outcomes.

Chest physiotherapy for acute bronchiolitis in paediatric patients between 0 and 24 months old

BACKGROUND

Acute bronchiolitis is the leading cause of medical emergencies during winter months in infants younger than 24 months old. Chest physiotherapy is sometimes used to assist infants in the clearance of secretions in order to decrease ventilatory effort. This is an update of a Cochrane Review first published in 2005 and updated in 2006, 2012, and 2016.

OBJECTIVES

To determine the efficacy of chest physiotherapy in infants younger than 24 months old with acute bronchiolitis. A secondary objective was to determine the efficacy of different techniques of chest physiotherapy (vibration and percussion, passive exhalation, or instrumental).

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, LILACS, Web of Science, PEDro (October 2011 to 20 April 2022), and two trials registers (5 April 2022).

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which chest physiotherapy was compared to control (conventional medical care with no physiotherapy intervention) or other respiratory physiotherapy techniques in infants younger than 24 months old with bronchiolitis.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

Our update of the searches dated 20 April 2022 identified five new RCTs with 430 participants. We included a total of 17 RCTs (1679 participants) comparing chest physiotherapy with no intervention or comparing different types of physiotherapy. Five trials (246 participants) assessed percussion and vibration techniques plus postural drainage (conventional chest physiotherapy), and 12 trials (1433 participants) assessed different passive flow-oriented expiratory techniques, of which three trials (628 participants) assessed forced expiratory techniques, and nine trials (805 participants) assessed slow expiratory techniques. In the slow expiratory subgroup, two trials (78 participants) compared the technique with instrumental physiotherapy techniques, and two recent trials (116 participants) combined slow expiratory techniques with rhinopharyngeal retrograde technique (RRT). One trial used RRT alone as the main component of the physiotherapy intervention. Clinical severity was mild in one trial, severe in four trials, moderate in six trials, and mild to moderate in five trials. One study did not report clinical severity. Two trials were performed on non-hospitalised participants. Overall risk of bias was high in six trials, unclear in five, and low in six trials. The analyses showed no effects of conventional techniques on change in bronchiolitis severity status, respiratory parameters, hours with oxygen supplementation, or length of hospital stay (5 trials, 246 participants).  Regarding instrumental techniques (2 trials, 80 participants), one trial observed similar results in bronchiolitis severity status when comparing slow expiration to instrumental techniques (mean difference 0.10, 95% confidence interval (C) -0.17 to 0.37).  Forced passive expiratory techniques failed to show an effect on bronchiolitis severity in time to recovery (2 trials, 509 participants; high-certainty evidence) and time to clinical stability (1 trial, 99 participants; high-certainty evidence) in infants with severe bronchiolitis. Important adverse effects were reported with the use of forced expiratory techniques.  Regarding slow expiratory techniques, a mild to moderate improvement was observed in bronchiolitis severity score (standardised mean difference -0.43, 95% CI -0.73 to -0.13; I2 = 55%; 7 trials, 434 participants; low-certainty evidence). Also, in one trial an improvement in time to recovery was observed with the use of slow expiratory techniques. No benefit was observed in length of hospital stay, except for one trial which showed a one-day reduction. No effects were shown or reported for other clinical outcomes such as duration on oxygen supplementation, use of bronchodilators, or parents' impression of physiotherapy benefit.

AUTHORS' CONCLUSIONS

We found low-certainty evidence that passive slow expiratory technique may result in a mild to moderate improvement in bronchiolitis severity when compared to control. This evidence comes mostly from infants with moderately acute bronchiolitis treated in hospital. The evidence was limited with regard to infants with severe bronchiolitis and those with moderately severe bronchiolitis treated in ambulatory settings. We found high-certainty evidence that conventional techniques and forced expiratory techniques result in no difference in bronchiolitis severity or any other outcome. We found high-certainty evidence that forced expiratory techniques in infants with severe bronchiolitis do not improve their health status and can lead to severe adverse effects. Currently, the evidence regarding new physiotherapy techniques such as RRT or instrumental physiotherapy is scarce, and further trials are needed to determine their effects and potential for use in infants with moderate bronchiolitis, as well as the potential additional effect of RRT when combined with slow passive expiratory techniques. Finally, the effectiveness of combining chest physiotherapy with hypertonic saline should also be investigated.

Long-acting beta2-agonists for chronic asthma in adults and children where background therapy contains varied or no inhaled corticosteroid

BACKGROUND

Asthma is a common respiratory disease among both adults and children and short acting inhaled beta-2 agonists are used widely for 'reliever' bronchodilator therapy. Long acting beta-2 agonists (LABA) were introduced as prospective 'symptom controllers' in addition to inhaled corticosteroid 'preventer' therapy (ICS). In this updated review we have included studies in which patients were either not on ICS as a group, or in which some patients, but not all, were on ICS to complement previous systematic reviews of studies where LABA was given in patients uniformly receiving ICS. We have focussed particularly on serious adverse events, given previous concerns about potential risks, especially of death, from regular beta-2 agonist use.

OBJECTIVES

This review aimed to determine the benefit or detriment on the primary outcome of asthma control with the regular use of LABA compared with placebo, in mixed populations in which only some were taking ICS and in populations not using ICS therapy.

SEARCH STRATEGY

We carried out searches using the Cochrane Airways Group trial register, most recently in October 2005. We searched bibliographies of identified RCTs for additional relevant RCTs and contacted authors of identified RCTs for other published and unpublished studies.

SELECTION CRITERIA

All randomised studies of at least four weeks duration, comparing a LABA given twice daily with a placebo, in chronic asthma. Selection criteria to this updated review have been altered to accommodate recently published Cochrane reviews on combination and addition of LABA to ICS therapy. Studies in which all individuals were uniformly taking ICS were excluded from this review.

DATA COLLECTION AND ANALYSIS

Two reviewers performed data extraction and study quality assessment independently. We contacted authors of studies for missing data.

MAIN RESULTS

Sixty-seven studies (representing 68 experimental comparisons) randomising 42,333 participants met the inclusion criteria. Salmeterol was used as long-acting agent in 50 studies and formoterol fumarate in 17. The treatment period was four to nine weeks in 29 studies, and 12 to 52 weeks in 38 studies. Twenty-four studies did not permit the use of ICS, and forty permitted either inhaled corticosteroid or cromones (in three studies this was unclear). In these studies between 22% and 92% were taking ICS, with a median of 62%. There were significant advantages to LABA treatment compared to placebo for a variety of measurements of airway calibre including morning peak expiratory flow (PEF), evening PEF and FEV1. They were associated with significantly fewer symptoms, less use of rescue medication and higher quality of life scores. This was true whether patients were taking LABA in combination with ICS or not. Findings from SMART (a recently published surveillance study) indicated significant increases in asthma related deaths, respiratory related deaths and combined asthma related deaths and life threatening experiences. The absolute increase in asthma-related mortality was consistent with an increase of around one per 1250 patients treated with LABA for six months, but the confidence intervals are wide (from 700 to 10,000). Post-hoc exploratory subgroups suggested that African-Americans and those not on inhaled corticosteroids were at particular risk for the primary end-point of death or life-threatening asthma event. There was also a suggestion of an increase in exacerbation rate in children. Pharmacologically predicted side effects such as headache, throat irritation, tremor and nervousness were more frequent with LABA treatment.

AUTHORS' CONCLUSIONS

LABA are effective in the control of chronic asthma in the "real-life" subject groups included. However there are potential safety issues which call into question the safety of LABA, particularly in those asthmatics who are not taking ICS, and it is not clear why African-Americans were found to have significant differences in comparison to Caucasians for combined respiratory-related death and life threatening experiences, but not for asthma-related death.