Bi-level CPAP does not change central blood flow in preterm infants with respiratory distress syndrome.

Giulia Aquilano,Arianna Aceti,Giacomo Faldella,Francesca Vitali,Silvia Galletti

doi:10.1186/1824-7288-40-60

Abstract

BackgroundCurrent literature provides limited data on the hemodynamic changes that may occur during bi-level continuous positive airway pressure (CPAP) support in preterm infants. However, the application of a positive end-expiratory pressure may be transmitted to the heart and the great vessels resulting in changes of central blood flow.ObjectiveTo assess changes in central blood flow in infants with respiratory distress syndrome (RDS) during bi-level CPAP support.DesignA prospective study was performed in a cohort of 18 Very-Low-Birth-Weight Infants who were put on nasal CPAP support (4–5 cmH2O) because they developed RDS within the first 24–72 hours of life. Each subject was switched to bi-level CPAP support (Phigh 8 cmH2O, Plow 4–5 cmH2O, Thigh 0.5-0.6 seconds, 20 breaths/min) for an hour. An echocardiographic study and a capillary gas analysis were performed before and after the change of respiratory support.ResultsNo differences between n-CPAP and bi-level CPAP in left ventricular output (LVO, 222.17 ± 81.4 vs 211.4 ± 75.3 ml/kg/min), right ventricular output (RVO, 287.8 ± 96 vs 283.4 ± 87.4 ml/kg/min) and superior vena cava flow (SVC, 135.38 ± 47.8 vs 137.48 ± 46.6 ml/kg/min) were observed. The hemodynamic characteristics of the ductus arteriosus were similar. A significant decrease in pCO2 levels after bi-level CPAP ventilation was observed; pCO2 variations did not correlate with modifications of central blood flow (LVO: ρ = 0.11, p = 0,657; RVO: ρ = −0.307, p = 0.216; SVC: ρ = −0.13, p = 0.197).ConclusionsCentral blood flow doesn’t change during bi-level CPAP support, which could become a hemodinamically safe tool for the treatment of RDS in preterm infants.

Highlights

Bi-level continuous positive airway pressure (CPAP) is a form of respiratory support routinely used to assist adults and children
The present study aims to evaluate the hemodynamic effects on cardiac outputs and venous return of bi-level CPAP in a population of Very Low Birth Weight Infants (VLBWIs) with respiratory distress syndrome (RDS)
Fourteen subjects (43.8%) were excluded for the following reasons: 2 infants were on mechanical ventilation, 6 without respiratory support or with nasal cannulae, 2 infants had congenital heart disease and 4 were not enrolled because the investigator was unavailable at the time of the study

Summary

Introduction

Bi-level CPAP is a form of respiratory support routinely used to assist adults and children. The cycle time can be either selected by the operator or synchronized with the patient’s respiratory effort Both IPAP and EPAP are generated by an increase in the gas flow through the circuit without closing the expiratory valve enabling the patient to exhale anytime, even during the IPAP phase [1]. By applying a constant distending pressure to the airways n-CPAP maintains the functional residual capacity (FRC) of the lungs through alveolar recruitment and stabilization. This constant pressure prevents alveolar collapse during expiration, improves gas exchange and reduces the work of breathing facilitating the inspiratory phase [3]. The application of a positive end-expiratory pressure may be transmitted to the heart and the great vessels resulting in changes of central blood flow

Methods

Results

Conclusion