Continuous distending pressure for respiratory distress in preterm infants

Review question: In spontaneously breathing preterm infants with respiratory failure, does continuous distending pressure (CDP) of the lung reduce the need for assisted ventilation and other associated complications of prematurity?

Background: Respiratory distress syndrome (RDS) is the most common cause of disease and death in babies born before 34 weeks' gestation. Intermittent positive pressure ventilation (IPPV) has been the standard way of helping these babies breathe. A simpler method of assisting breathing is to provide continuous distending pressure of the lung, either as continuous positive pressure to the airway or as continuous negative pressure (partial vacuum).

Search dates: The search was conducted in April 2015.

Study characteristics: Six studies of moderate quality were identified for inclusion.

The source of distending pressure was a negative pressure chamber in two studies, face mask continuous positive airway pressure (CPAP) in two studies, nasal CPAP in one study and negative pressure for less severe illness and endotracheal CPAP when more severe in another study. The studies were small, and four of the six were conducted before surfactant therapy was available.

Key results: The review of trials found that outcomes for babies were improved. Fewer required IPPV and fewer died, and with these two outcomes combined, fewer babies died or required IPPV. It was also found that CDP can increase the rate of pneumothorax (air outside the lung within the chest cavity).

Conclusion: Some meaningful benefits were found when continuous distending pressure (CDP) was used for respiratory distress syndrome in preterm babies.

Authors' conclusions: 

In preterm infants with respiratory distress, the application of CDP as CPAP or CNP is associated with reduced respiratory failure and mortality and an increased rate of pneumothorax. Four out of six of these trials were done in the 1970s. Therefore, the applicability of these results to current practice is difficult to assess. Further research is required to determine the best mode of administration.

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Background: 

Respiratory distress syndrome (RDS) is the single most important cause of morbidity and mortality in preterm infants. In infants with progressive respiratory insufficiency, intermittent positive pressure ventilation (IPPV) with surfactant is the standard treatment for the condition, but it is invasive, potentially resulting in airway and lung injury. Continuous distending pressure (CDP) has been used for the prevention and treatment of RDS, as well as for the prevention of apnoea, and in weaning from IPPV. Its use in the treatment of RDS might reduce the need for IPPV and its sequelae.

Objectives: 

To determine the effect of continuous distending pressure (CDP) on the need for IPPV and associated morbidity in spontaneously breathing preterm infants with respiratory distress.

Subgroup analyses were planned on the basis of birth weight (> or < 1000 or 1500 g), gestational age (groups divided at about 28 weeks and 32 weeks), methods of application of CDP (i.e. CPAP and CNP), application early versus late in the course of respiratory distress and high versus low pressure CDP and application of CDP in tertiary compared with non-tertiary hospitals, with the need for sensitivity analysis determined by trial quality.

At the 2008 update, the objectives were modified to include preterm infants with respiratory failure.

Search strategy: 

We used the standard search strategy of the Neonatal Review Group. This included searches of the Oxford Database of Perinatal Trials, the Cochrane Central Register of Controlled Trials (CENTRAL, 2015 Issue 4), MEDLINE (1966 to 30 April 2015) and EMBASE (1980 to 30 April 2015) with no language restriction, as well as controlled-trials.com, clinicaltrials.gov and the International Clinical Trials Registry Platform of the World Health Organization (WHO).

Selection criteria: 

All random or quasi-random trials of preterm infants with respiratory distress were eligible. Interventions were continuous distending pressure including continuous positive airway pressure (CPAP) by mask, nasal prong, nasopharyngeal tube or endotracheal tube, or continuous negative pressure (CNP) via a chamber enclosing the thorax and the lower body, compared with spontaneous breathing with oxygen added as necessary.

Data collection and analysis: 

We used standard methods of The Cochrane Collaboration and its Neonatal Review Group, including independent assessment of trial quality and extraction of data by each review author.

Main results: 

We included six studies involving 355 infants - two using face mask CPAP, two CNP, one nasal CPAP and one both CNP (for less ill babies) and endotracheal CPAP (for sicker babies). For this update, we included no new trials.

Continuous distending pressure (CDP) is associated with lower risk of treatment failure (death or use of assisted ventilation) (typical risk ratio (RR) 0.65, 95% confidence interval (CI) 0.52 to 0.81; typical risk difference (RD) -0.20, 95% CI -0.29 to -0.10; number needed to treat for an additional beneficial outcome (NNTB) 5, 95% CI 4 to 10; six studies; 355 infants), lower overall mortality (typical RR 0.52, 95% CI 0.32 to 0.87; typical RD -0.15, 95% CI -0.26 to -0.04; NNTB 7, 95% CI 4 to 25; six studies; 355 infants) and lower mortality in infants with birth weight above 1500 g (typical RR 0.24, 95% CI 0.07 to 0.84; typical RD -0.28, 95% CI -0.48 to -0.08; NNTB 4, 95% CI 2.00 to 13.00; two studies; 60 infants). Use of CDP is associated with increased risk of pneumothorax (typical RR 2.64, 95% CI 1.39 to 5.04; typical RD 0.10, 95% CI 0.04 to 0.17; number needed to treat for an additional harmful outcome (NNTH) 17, 95% CI 17.00 to 25.00; six studies; 355 infants). We found no difference in bronchopulmonary dysplasia (BPD), defined as oxygen dependency at 28 days (three studies, 260 infants), as well as no difference in outcome at nine to 14 years (one study, 37 infants).

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