Gastro-oesophageal reflux in mechanically ventilated preterm infants

Preliminary study in to the incidence of gastroesophageal reflux (GER) in high risk neonates admitted to NICU

OBJECTIVE

To find out the incidence of Gastro-esophageal reflux (GER) in neonates at risk for it and compare this with the incidence in the controls.

METHODS

This prospective case control study was conducted on 34 neonates. Twenty-four test high risk neonates comprised of preterms, neonates on mechanical ventilation neonates with ALTE(Acute Life Threatening Episode) and post-operative neonates (Tracheo-esophageal fistula, congenital diaphragmatic hernia). There were ten matched controls. Esophageal pHmetry was done using double sensor antimony pH probe and the two groups were compared. Significant reflux was defined as any reflux on pharyngeal sensor (grade 4 reflux) or a Reflux Index or RI (amount of time the esophageal pH remained <4) >20%.Analysis were done using Fisher Exact t test and Chi square test.

RESULTS

Mean gestational age was 34.87(3.86) wk and 33.7(3.29) wk in the test and control groups respectively, while mean BW was 2186.02(814.57) g and 1851.2(592.93) g in each respective group. In the test group 10 were symptomatic, 5 were on mechanical ventilation, 8 were on CPAP and one was post-operation case. Difference in the incidence of significant RI in test and control group was not statistically significant. Incidence between various group of neonates in test group showed no statistical significance either. However, the incidence of grade IV reflux in test group was 8/24 and control 0/10 and this difference was statistically significant. Reflux did increase when period of gestation decreased and the difference was statistically significant.

CONCLUSIONS

Clinically significant grade IV GER was more in high risk (test) neonates than control.

A study of the effect of nasal modes of ventilation on the incidence of gastro-oesophageal reflux in preterm neonates

BACKGROUND

Nasal modes of respiratory support cause variable amounts of gastric dilatation which may increase gastro-oesophageal reflux (GER) in preterms. To compare the incidence of GER in nasally ventilated, preterm babies with controls (babies not on ventilation).

TYPE OF STUDY

A prospective, observational comparative study.

METHOD

Twenty-three preterm babies of gestational age 28-36 weeks and weight ranging between 1,000 g and < 2,500 g on either nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure venti-lation (nIPPV) were assessed for GER. They were compared with controls not on ventilation some of who were test babies when off ventilation (subgroup A) and some were unrelated babies not on ventilator but matched for gestational age and weight with test babies (subgroup B). All babies were subjected to continuous, oesophageal pH monitoring with dual sensor (upper and lower oesophageal) catheters. Reflux index (RI) was calculated as the percentage of study time the lower oesophageal pH was < 4. Primary outcome was the RI in the test and controls groups. Secondary outcome was the temporal relation of the reflux with symptoms if any. Numerical data were shown as mean with standard deviation and statistical comparisons were done using the χ(2)-test, Fischer test, and t-test wherever applicable.

RESULTS

The RI was higher in ventilated babies as compared to the control group, particularly in the subgroup A, where test babies formed their own controls. Grade IV reflux (7 cases) was seen only in the ventilated babies. There was no difference in the incidence of GER in babies on nCPAP as compared with nIPPV. Grade IV reflux could not be reliably predicted by RI alone. No definite temporal relation between episodes of reflux and symptoms could be determined in this study.

CONCLUSION

There is an increase in GER in preterms on nasal modes of ventilation. A combination of upper (pharyngeal) and lower oesophageal sensors are preferred to a single lower oesophageal sensor when assessing GER by oesophageal pHmetry in neonates.

Anti-reflux surgery for the neonatal intensive care-dependent infant

AIM

The benefit of anti-reflux surgery for gastro-oesophageal reflux (GOR) in early infancy is uncertain. The aim of this study was to assess the value of Nissen fundoplication in a group of infants with severe GOR.

METHODS

10 infants underwent Nissen fundoplication for gastro-oesophageal reflux following a failure of medical management. All had suffered life-threatening respiratory episodes as a consequence of gastro-oesophageal reflux, and were neonatal intensive care-dependent. Median (range) birth weight was 1.26 kg (0.48-3.8 kg), gestation 30 weeks (25-38 weeks); at surgery, weight was 3.25 kg (2.5-6.1 kg) at a corrected age of 11.5 weeks (term-22) weeks. For each infant, the success of enteral feeding and the level of support required pre- and post-operatively was compared, and where appropriate, the facilitation of palliative feeding was assessed. Median follow-up was 14 (3-36) months.

RESULTS

No infant suffered intra-operative morbidity or mortality. One infant died within 1 month of surgery from a collapse unrelated to surgery. Eight of nine surviving infants were discharged from intensive care following extubation and the establishment of enteral feeding. One patient died of severe bronchopulmonary dysplasia 3 months post-surgery. One infant developed a gastrostomy site infection, and two required gastrostomy tube replacement within 6 months of surgery. All were thriving at follow-up. Two infants with a congenital myopathy died as a result of their muscle disease at 9 and 11 months post-operatively.

CONCLUSIONS

Nissen fundoplication is a feasible, effective and safe operation in severe gastro-oesophageal reflux unresponsive to medical treatment in term and pre-term infants. It has an additional important role in facilitating safe palliative enteral feeding in infants with a diagnosis incompatible with survival into adulthood.

Enteral feeding of the micropremie

Clinical practice demands knowledge of gastrointestinal ontogeny and the factors that affect our ability to use enteral feeding in the micropremie. The decisions regarding milk type (when and how it should be given) are considered in the light of current physiologic and clinical evidence. Special considerations apply in the micropremie who is also small for gestational age and NEC must be avoided. Trophic feeding now has an established role, allowing the infant to benefit from enteral feeds even when full nutritive milk feeding is not possible.

Disorders of the oesophagus and stomach in infants

Pathological processes and disease entities in the upper gastrointestinal (GI) tract, specifically those of the oesophagus and the stomach in infancy, have received a disproportionately small amount of attention until recently when appreciation of their pathophysiology and concordant importance in terms of symptomatology has been highlighted. This is probably a phenomenon secondary to improved diagnostic yield from the recent technical advances in areas such as infant endoscopy and a shift in opinion regarding the pathophysiological origin of ubiquitous symptoms of infancy such as feeding disorders, colic and irritability. In addition, the apparently complex interactions of various aetiological factors such as pH-independent gastro-oesophageal reflux (GOR), cow's milk protein intolerance (CMPI), Helicobacter pylori gastritis and upper GI motor disorders have in the past 1-2 years become underlined in terms of aetiopathogenesis and have radically changed thinking regarding diagnosis and therapy of infants with apparent upper-GI-associated symptoms. The contribution to comprehension of infant upper GI disorders of inflammatory paradigms and ontogeny of the upper GI tract is also a recent area worthy of mention. The recent advances in all of these areas and their contribution to the understanding, and subsequent diagnosis and therapy, of upper GI symptoms and their explanation by way of aetiopathogenesis will be explored in this chapter.

Simultaneous tracheal and oesophageal pH monitoring during mechanical ventilation

OBJECTIVE

To simultaneously record tracheal and oesophageal pH in mechanically ventilated children to determine: (1) the feasibility and safety of the method; (2) the incidence of gastro-oesophageal reflux (GOR) and pulmonary contamination; and (3) their associated risk factors.

DESIGN

Prospective study.

SETTING

Paediatric intensive care unit in a university hospital.

PATIENTS

Twenty mechanically ventilated children (mean age 6.7 years) who met the following inclusion criteria: endotracheal tube with an internal diameter of 4 mm or more (cuffed or uncuffed), mechanical ventilation for an acute disease, no treatment with antiacids, prokinetics, or H2-receptor blockers, and no nasogastric or orogastric tube.

METHODS

The tracheal antimony pH probe was positioned 1 cm below the distal end of the endotracheal tube. The oesophageal antimony pH probe was positioned at the lower third of the oesophagus. pH was recorded on a double channel recorder and analysed with EsopHogram 5.01 software and by examination of the trace. The following definitions were used: GOR index, percentage of time pH < 4; pathological GOR, GOR index > 4.8%; tracheal reflux, fall in tracheal pH < 4, 4.5, or 5, or a decrease of one unit from baseline, in both cases preceded by an episode of GOR. The results were analysed statistically by Fisher's exact and the Kruskal-Wallis test.

RESULTS

The procedure was well tolerated and the median duration of analysable recording was 6 hours (range 5-22.6). Pathological GOR was observed in eight (40%) children. GOR was more frequent with an uncuffed endotracheal tube than with a cuffed one (p = 0.01). Tracheal reflux (pH < 4) was observed in four children (20%) without clinical evidence of pulmonary aspiration. Episodes of tracheal reflux were associated with a GOR index > 10% (p < 0.01) and were more frequent with a maximal inspiratory pressure of < 25 cm H2O (p = 0.03), but were not related to the indication for mechanical ventilation, whether the endotracheal tube was cuffed or not, age, or drug treatment.

CONCLUSIONS

Simultaneous tracheal and oesophageal pH monitoring was feasible in the setting of this study. Tracheal reflux can occur without pathological GOR, and GOR may occur without tracheal reflux. Further prospective studies in larger groups of patients are now justified.

Developmental maturation of gastro-oesophageal reflux in preterm infants

The frequency and duration of gastro-oesophageal reflux were examined in 40 preterm infants and compared with a previously published healthy cohort of 74 term infants. Selection required that the infants were born between 24 and 32 weeks' gestation, had a normal head ultrasound and were studied at term post-menstrual age. Multi-channel pen recordings of sleep state, movement, breathing and acid reflux were made. In term and preterm infants the frequency and duration of reflux were greatest in active sleep, rare in quiet sleep and significantly less in preterm than term infants in wakefulness and active sleep (p < 0.05). The fewer and shorter episodes in preterm infants could not be explained by sleep state movement, gestational or postnatal age, days intubated, days on oxygen or the lowest pH of reflux episodes.