No effect of sodium alginate (Gaviscon ) on apnoea of prematurity induced by gastro-oesophageal reflux

Background and aims: Apnoea of prematurity (AOP) is one of the most common and frequently recurring problem in preterm infants and its relationship with gastro-oesophageal reflux (GOR) is widely debated in literature. Our previous study highlights an increase of AOP in periods after GOR. The aim of this study is to evaluate the efficacy of sodium alginate (Gaviscon®) in reducing frequency of AOP related to GOR in preterm infants by a simultaneous and synchronized pH-Intraluminal Impedance Monitoring (pH-MII) and polysomnography in preterm infants. Materials and methods: Twenty-eight preterm infants (gestational age < 33 weeks; mean birth weight 1100 gr) were studied as they had recurrent apneas. Patients who were taking drugs influencing gastrointestinal motility or gastric acidity and infants with malformations, major gastrointestinal problems or sepsis were ruled out. They underwent a six-hour simultaneous and synchronized recording of polysomnography and pH-impedance monitoring (pH-MII). Polysomnography detects apneas by recording of breathing movement, nasal airflow, electrocardiogram and pulse oximeter saturation. To avoid possible artefacts a portable camera video registered the infants during all the recording. We considered as apnoeas each oral/nasal flow cessation lasting at least 5 seconds. Apnoeas were then classified as central (CA), obstructive (OA) and mixed (MA) depending on absence or presence of obstructed respiratory efforts. pH-MII is the state-of-the-art methodology for GOR detection in preterm newborns. By pH-MII monitoring we registered both acid and non acid GORs. A standard period of 30 seconds after the onset of GOR episodes was chosen in order to test the temporal relation between GOR and apnoea. Apnoeas detected within 30 seconds after the onset of a GOR episode were defined GOR-induced. Layouts involved 2 post-prandial periods lasting 3 hours each one, characterized by presence or absence of treatment with Gaviscon® (2cc/kg) after meal. The period after Gaviscon administration was called GAV, the other No-GAV. The meal after which Gaviscon® was administered was randomly assigned in order to avoid any possible carry-over effects. During the analysis of layouts the investigator was blind to the administration of Gaviscon. pH-MII and polysomnography data were independently analyzed by two different investigators and then compared. Data obtained during these two periods were finally compared. Results: Seven-hundred-fifteen apnoeas were recorded during 165 hours of registration and then divided according to the administration of Gaviscon®. Comparing data found after the treatment with those registered during freetreatment periods, we found no differences in number of total apnoeas (AOP during GAV vs NO-GAV was 12.4±9.5 vs 13.1±12.0 apnoeas/period, p=0.99) and related events. However a significant reduction in the number of GOR episodes after using Gaviscon® was observed (GOR during GAV vs NO-GAV was 11.3±8.6 vs 19.1±10.5 events/period, p=0.001), but this data is not the same for each type of GOR. Actually the analysis of GOR highlighted as the acid episodes resulted less after Gaviscon®, whereas the administration of Gaviscon do not modify the number of non acid GORs. Conclusion: Our data demonstrate as the administration of Gaviscon® has not effects on the AOP. Nevertheless there is a significant reduction of acid GORs after administration of Gaviscon®.We hypothesized that the lack effect on AOP could be explained by the poor efficacy in reducing non acid GORs, particularly relevant in preterm infant