ApnoeCPAP

BACKGROUND

Apnoea of prematurity (AOP) is a common problem in preterm infants which can be treated with various modes of nasal continuous positive airway pressure (NCPAP) or nasal intermittent positive pressure ventilation (NIPPV). It is not known which mode of NCPAP or NIPPV is most effective for AOP.

OBJECTIVE

To assess the effect of four NCPAP/NIPPV systems on the rate of bradycardias and desaturation events in very low birthweight infants.

METHODS

Sixteen infants (mean gestational age at time of study 31 weeks, 10 males) with AOP were enrolled in a randomised controlled trial with a crossover design. The infants were allocated to receive nasal pressure support using four different modes for 6 h each: NIPPV via a conventional ventilator, NIPPV and NCPAP via a variable flow device, and NCPAP delivered via a constant flow underwater bubble system. The primary outcome was the cumulative event rate of bradycardias (< or =80 beats per minute) and desaturation events (< or =80% arterial oxygen saturation), which was obtained from cardio-respiratory recordings.

RESULTS

The median event rate was 6.7 per hour with the conventional ventilator in NIPPV mode, and 2.8 and 4.4 per hour with the variable flow device in NCPAP and NIPPV mode, respectively (p value<0.03 for both compared to NIPPV/conventional ventilator). There was no significant difference between the NIPPV/conventional ventilator and the underwater bubble system.

CONCLUSION

A variable flow NCPAP device may be more effective in treating AOP in preterm infants than a conventional ventilator in NIPPV mode. It remains unclear whether synchronised NIPPV would be even more effective.

BACKGROUND

Nasal continuous positive airway pressure (NCPAP) is used to support preterm infants recently extubated, those experiencing significant apnoea of prematurity and those with respiratory distress soon after birth as an alternative to intubation and ventilation. This review focuses exclusively on identifying the most effective pressure source and interface for NCPAP delivery in preterm infants.

OBJECTIVES

To determine which technique of pressure generation and which type of nasal interface for NCPAP delivery most effectively reduces the need for additional respiratory support in preterm infants extubated to NCPAP following intermittent positive pressure ventilation (IPPV) for respiratory distress syndrome (RDS) or in those treated with NCPAP soon after birth.

SEARCH STRATEGY

The strategy included searches of MEDLINE (1966 - 2006), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2006) CINAHL, abstracts from conference proceedings, cross-referencing of previous reviews and the use of expert informants.

SELECTION CRITERIA

Randomised or quasi-randomised trials comparing different techniques of NCPAP pressure generation and/or nasal interfaces in preterm infants extubated to NCPAP following IPPV for RDS or treated with NCPAP soon after birth.

DATA COLLECTION AND ANALYSIS

Data was extracted and analysed by the first three authors. Dichotomous results were analysed using the relative risk (RR), risk difference (RD) and number needed to treat (NNT).

MAIN RESULTS

1. Preterm infants being extubated to NCPAP following a period of IPPV for RDS:Meta-analysis of the results from Davis 2001 and Roukema 1999a demonstrated that short binasal prongs are more effective at preventing re-intubation than single nasal or nasopharyngeal prongs [typical RR 0.59 (CI: 0.41, 0.85), typical RD -0.21 (CI: -0.35, -0.07), NNT 5 (CI: 3, 14)]. In one study comparing short binasal prong devices (Sun 1999), the re-intubation rate was significantly lower with the Infant Flow Driver than with the Medicorp prong [RR 0.33 (CI: 0.17, 0.67), RD -0.32 (CI: -0.49, -0.15), NNT 3 (CI: 2, 7)]. The other study comparing short binasal prong devices (Infant Flow Driver versus INCA prongs, Stefanescu 2003) demonstrated no significant difference in the re-intubation rate but did show a significant reduction in the total days in hospital in the Infant Flow Driver group [MD -12.60 (95% CI: -22.81, -2.39) days].2. Preterm infants primarily treated with NCPAP soon after birth:In the one trial identified, Mazzella 2001 found a significantly lower oxygen requirement and respiratory rate in those randomised to short binasal prongs when compared with CPAP delivered via nasopharyngeal prong. The requirement for intubation beyond 48 hours from randomisation was not assessed.3. Studies randomising preterm infants to different NCPAP systems using broad inclusion criteriaThe studies of Rego 2002 and Buettiker 2004 did not examine the primary outcomes of this review. Of the secondary outcomes, Rego 2002 demonstrated a significantly higher incidence of nasal hyperaemia with the use of the Argyle prong compared with Hudson prongs [RR 2.39 (95% CI: 1.27, 4.50), RD 0.28 (95% CI: 0.10, 0.46)]. One study comparing different techniques of pressure generation is awaiting further assessment as it is currently available in abstract form only.

AUTHORS' CONCLUSIONS

Short binasal prong devices are more effective than single prongs in reducing the rate of re-intubation. Although the Infant Flow Driver appears more effective than Medicorp prongs the most effective short binasal prong device remains to be determined. The improvement in respiratory parameters with short binasal prongs suggests they are more effective than nasopharyngeal CPAP in the treatment of early RDS. Further studies incorporating longer-term outcomes are required. Studies are also needed to determine the optimal pressure source for the delivery of NCPAP.