Review question
Do drugs and other treatments in babies with abnormally rapid breathing (known as transient tachypnoea of the newborn) improve lung function and reduce the need for breathing support (i.e. mechanical ventilation) and/or duration of symptoms?
Background
Transient tachypnoea of the newborn is characterised by rapid breathing (more than 60 breaths per minute) and signs of respiratory distress (difficulty in breathing). It typically appears within the first two hours of life in babies born at or after 34 weeks' of pregnancy. Although transient tachypnoea of the newborn usually improves without treatment, it might be associated with wheezing in late childhood. This Cochrane overview reported and critically analysed the available evidence on the benefit and harms of different treatments for the management of transient tachypnoea of the newborn.
Study characteristics
We included six Cochrane Reviews. Four of them compared drugs (salbutamol, epinephrine, corticosteroid, and diuretics) with placebo, whilst the remaining two reviews assessed the effects of giving a lesser quantity of fluids and breathing (respiratory) support without insertion of a tube into the lungs. Salbutamol, epinephrine, and corticosteroids remove the excess fluid from the lungs, whereas a diuretic is a drug that promotes the secretion of lung fluid in the urine.
The evidence is up-to-date as of July 2021.
Results
Due to the very limited available evidence, we could not answer the question of our overview. Salbutamol may reduce the duration of rapid breathing compared to placebo. The studies on epinephrine and corticosteroids did not provide information on this outcome. The evidence is very uncertain for the effect of diuretics compared to placebo. The studies on giving a lesser quantity of fluids did not provide information on this outcome.
The evidence is very uncertain regarding the effect of different types of respiratory support without the insertion of a tube into the lungs compared to oxygen or compared to each other on the duration of rapid breathing. We are uncertain about the effects of salbutamol, epinephrine, and corticosteroids in reducing the need for mechanical ventilation (use of a machine to help the patient breathe where a tube is inserted into the lungs). The studies on diuretics did not provide information on this outcome. We are uncertain about the effects of respiratory support without insertion of a tube into the lungs, and giving a lesser quantity of fluids in reducing the need for mechanical ventilation.
Certainty of evidence
The certainty of the evidence was low for salbutamol for duration of rapid breathing, and very low for all other outcomes and treatments. The studies either did not report information that we could use or produced findings in which we have very little confidence. These studies were small and used methods likely to introduce errors in their results.
This overview summarises the evidence from six Cochrane Reviews of randomised trials regarding the effects of postnatal interventions in the management of TTN. Salbutamol may reduce the duration of tachypnoea slightly. We are uncertain as to whether salbutamol reduces the need for mechanical ventilation. We are uncertain whether epinephrine, corticosteroids, diuretics, fluid restriction, or non-invasive respiratory support reduces the duration of tachypnoea and the need for mechanical ventilation, due to the extremely limited evidence available. Data on harms were lacking.
Transient tachypnoea of the newborn (TTN) is characterised by tachypnoea and signs of respiratory distress. It is caused by delayed clearance of lung fluid at birth. TTN typically appears within the first two hours of life in term and late preterm newborns. Although it is usually a self‐limited condition, admission to a neonatal unit is frequently required for monitoring, the provision of respiratory support, and drugs administration. These interventions might reduce respiratory distress during TTN and enhance the clearance of lung liquid. The goals are reducing the effort required to breathe, improving respiratory distress, and potentially shortening the duration of tachypnoea. However, these interventions might be associated with harm in the infant.
The aim of this overview was to evaluate the benefits and harms of different interventions used in the management of TTN.
We searched the Cochrane Database of Systematic Reviews on 14 July 2021 for ongoing and published Cochrane Reviews on the management of TTN in term (> 37 weeks' gestation) or late preterm (34 to 36 weeks' gestation) infants. We included all published Cochrane Reviews assessing the following categories of interventions administered within the first 48 hours of life: beta-agonists (e.g. salbutamol and epinephrine), corticosteroids, diuretics, fluid restriction, and non-invasive respiratory support. The reviews compared the above-mentioned interventions to placebo, no treatment, or other interventions for the management of TTN. The primary outcomes of this overview were duration of tachypnoea and the need for mechanical ventilation. Two overview authors independently checked the eligibility of the reviews retrieved by the search and extracted data from the included reviews using a predefined data extraction form. Any disagreements were resolved by discussion with a third overview author. Two overview authors independently assessed the methodological quality of the included reviews using the AMSTAR 2 (A MeaSurement Tool to Assess systematic Reviews) tool. We used the GRADE approach to assess the certainty of evidence for effects of interventions for TTN management. As all of the included reviews reported summary of findings tables, we extracted the information already available and re-graded the certainty of evidence of the two primary outcomes to ensure a homogeneous assessment. We provided a narrative summary of the methods and results of each of the included reviews and summarised this information using tables and figures.
We included six Cochrane Reviews, corresponding to 1134 infants enrolled in 18 trials, on the management of TTN in term and late preterm infants, assessing salbutamol (seven trials), epinephrine (one trial), budesonide (one trial), diuretics (two trials), fluid restriction (four trials), and non-invasive respiratory support (three trials). The quality of the included reviews was high, with all of them fulfilling the critical domains of the AMSTAR 2. The certainty of the evidence was very low for the primary outcomes, due to the imprecision of the estimates (few, small included studies) and unclear or high risk of bias.
Salbutamol may reduce the duration of tachypnoea compared to placebo (mean difference (MD) −16.83 hours, 95% confidence interval (CI) −22.42 to −11.23, 2 studies, 120 infants, low certainty evidence). We did not identify any review that compared epinephrine or corticosteroids to placebo and reported on the duration of tachypnoea. However, one review reported on "trend of normalisation of respiratory rate", a similar outcome, and found no differences between epinephrine and placebo (effect size not reported). The evidence is very uncertain regarding the effect of diuretics compared to placebo (MD −1.28 hours, 95% CI −13.0 to 10.45, 2 studies, 100 infants, very low certainty evidence). We did not identify any review that compared fluid restriction to standard fluid rates and reported on the duration of tachypnoea. The evidence is very uncertain regarding the effect of continuous positive airway pressure (CPAP) compared to free-flow oxygen therapy (MD −21.1 hours, 95% CI −22.9 to −19.3, 1 study, 64 infants, very low certainty evidence); the effect of nasal high-frequency (oscillation) ventilation (NHFV) compared to CPAP (MD −4.53 hours, 95% CI −5.64 to −3.42, 1 study, 40 infants, very low certainty evidence); and the effect of nasal intermittent positive pressure ventilation (NIPPV) compared to CPAP on duration of tachypnoea (MD 4.30 hours, 95% CI −19.14 to 27.74, 1 study, 40 infants, very low certainty evidence).
Regarding the need for mechanical ventilation, the evidence is very uncertain for the effect of salbutamol compared to placebo (risk ratio (RR) 0.60, 95% CI 0.13 to 2.86, risk difference (RD) 10 fewer, 95% CI 50 fewer to 30 more per 1000, 3 studies, 254 infants, very low certainty evidence); the effect of epinephrine compared to placebo (RR 0.67, 95% CI 0.08 to 5.88, RD 70 fewer, 95% CI 460 fewer to 320 more per 1000, 1 study, 20 infants, very low certainty evidence); and the effect of corticosteroids compared to placebo (RR 0.52, 95% CI 0.05 to 5.38, RD 40 fewer, 95% CI 170 fewer to 90 more per 1000, 1 study, 49 infants, very low certainty evidence). We did not identify a review that compared diuretics to placebo and reported on the need for mechanical ventilation. The evidence is very uncertain regarding the effect of fluid restriction compared to standard fluid administration (RR 0.73, 95% CI 0.24 to 2.23, RD 20 fewer, 95% CI 70 fewer to 40 more per 1000, 3 studies, 242 infants, very low certainty evidence); the effect of CPAP compared to free-flow oxygen (RR 0.30, 95% CI 0.01 to 6.99, RD 30 fewer, 95% CI 120 fewer to 50 more per 1000, 1 study, 64 infants, very low certainty evidence); the effect of NIPPV compared to CPAP (RR 4.00, 95% CI 0.49 to 32.72, RD 150 more, 95% CI 50 fewer to 350 more per 1000, 1 study, 40 infants, very low certainty evidence); and the effect of NHFV versus CPAP (effect not estimable, 1 study, 40 infants, very low certainty evidence).
Regarding our secondary outcomes, duration of hospital stay was the only outcome reported in all of the included reviews. One trial on fluid restriction reported a lower duration of hospitalisation in the restricted-fluids group, but with very low certainty of evidence. The evidence was very uncertain for the effects on secondary outcomes for the other five reviews. Data on potential harms were scarce, as all of the trials were underpowered to detect possible increases in adverse events such as pneumothorax, arrhythmias, and electrolyte imbalances. No adverse effects were reported for salbutamol; however, this medication is known to carry a risk of tachycardia, tremor, and hypokalaemia in other settings.