Continuous distending pressure for respiratory distress syndrome in preterm infants

BACKGROUND: Respiratory distress syndrome (RDS) is the single most important cause of morbidity and mortality in preterm infants (Greenough 1998, Bancalari 1992). Intermittent positive pressure ventilation (IPPV) with surfactant is the standard treatment for the condition. The major difficulty with IPPV is that it is invasive, resulting in airway and lung injury and contributing to the development of chronic lung disease.

OBJECTIVES: In spontaneously breathing preterm infants with RDS, to determine if continuous distending pressure (CDP) reduces the need for IPPV and associated morbidity without adverse effects.

SEARCH STRATEGY: The standard search strategy of the Neonatal Review group was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2002), MEDLINE (1966-January 2002), and EMBASE (1980-January 2002), previous reviews including cross references, abstracts, conference and symposia proceedings, expert informants, journal hand searching mainly in the English language.

SELECTION CRITERIA: All trials using random or quasi-random allocation of preterm infants with RDS 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 lower body, compared with standard care.

DATA COLLECTION AND ANALYSIS: Standard methods of the Cochrane Collaboration and its Neonatal Review Group were used, including independent assessment of trial quality and extraction of data by each author.

MAIN RESULTS: CDP is associated with a lower rate of failed treatment (death or use of assisted ventilation) [summary RR 0.70 (0.55, 0.88), RD -0.22 (-0.35, -0.09), NNT 5 (3, 11)], overall mortality [summary RR 0.52 (0.32, 0.87), RD -0.15 (-0.26, -0.04), NNT 7 (4, 25)], and mortality in infants with birthweights above 1500 g [summary RR 0.24 (0.07, 0.84), RD -0.281 (-0.483, -0.078), NNT 4 (2, 13)]. The use of CDP is associated with an increased rate of pneumothorax [summary RR 2.36 (1.25, 5.54), RD 0.14 (0.04, 0.23), NNH 7 (4, 24)].

REVIEWER'S CONCLUSIONS: In preterm infants with RDS the application of CDP either as CPAP or CNP is associated with benefits in terms of reduced respiratory failure and reduced mortality. CDP is associated with an increased rate of pneumothorax. The applicability of these results to current practice is difficult to assess, given the intensive care setting of the 1970s when four out of five of these trials were done. Where resources are limited, such as in developing countries, CPAP for RDS may have a clinical role. Further research is required to determine the best mode of administration and its role in modern intensive care settings