Association between apparent life-threatening events and gastro-oesophageal reflux detected by multichannel intraluminal impedance

Abstracts / Digestive and Liver Disease 39 (2007) A49–A87 CO 10 ASSOCIATION BETWEEN APPARENT LIFE-THREATENING EVENTS AND GASTRO-OESOPHAGEAL REFLUX DETECTED BY MULTICHANNEL INTRALUMINAL IMPEDANCE N. Bucci a , A.M. Magist`a a , N.D. Rizzi a , S. Fico a , A. De Canio a , P. Logrillo a , L. Cavallo c , L. Armenio a , A. Villirillo b , F. Moramarco b , L. Brunetti a , R. Francavilla c a

Department Di Biomedicina dell’Et`a Evolutiva, Italy b Clinica Pediatrica Ospedale Perrino – Brindisi, Italy c CIRGEEE, Universit` a degli Studi di Bari, Italy

Background. Apparent life-threatening events (ALTEs) have been reported as supra-oesophageal complications of gastro-oesophageal reflux (GER) (Orenstein S et al., Am J Med 2001;111:60). The main problem in studying this association is that most of reflux events (RE) are buffered in infants and thus undetectable by traditional pH monitoring. Multichannel intraluminal impedance (MII) has been recently introduced as a pH-independent method to investigate the bolus transport in hollow organs. Based on this new technique, data in the literature remain controversial (Wenzl TG et al., Pediatric Pulmonology 2001;31:144; Mousa H et al., JPGN 2005;41:169). The aims of this study were: (a) to investigate whether there is a temporal association between cardiorespiratory (CR) events suggestive of ALTEs and RE, using combined pH/MII monitoring and (b) to compare, using combined ph/MII recording, infant patients with clinical history of ALTE to infant patients presenting typical and atypical symptoms suggestive of GER but without clinical history of ALTE. Patients and methods. All the consecutive infants referred to our Department for ALTEs, between October 2004 and February 2007, and who resulted negative to the appropriate investigations for this condition were enrolled. All infants (suspected of GER disease) undergoing MII-pH monitoring for a different indication than ALTE was used as non-ALTE group. Infants with ALTEs were investigated simultaneously with 6-h MIIpH monitoring (z-lab, Sandhill Scientific, Highlands Ranch, CO, USA) and polysomnography (ALICE II polygraph). A temporal association between CR events and RE was defined if both commenced within 30 s of each other. We studied, for each CR event, the symptom index (SI), the symptoms sensitivity index (SSI) and the symptoms association probability (SAP). Finally the 24-h ph/MII combined recording of ALTES and non-ALTE infants were compared. Results. Fifteen patients with clinical history of ALTE [6 M; median age 2.6 months (range 1.3–6.7 months)] and 15 patients with suspected GER disease [17 M; median age 6.3 months (range 1.6–8.9 months)] were enrolled. Out of the total 15 infants without ALTEs, 3 presented typical symptoms (vomiting and regurgitation), 11 (73%) presented atypical symptoms (cough) and 1 presented both typical and atypical symptoms. Overall, out of 336 CR events, we could detect an association with GER in 20 (6%) with no difference between acid or non-acid GER, duration or height of refluxes. SI was positive in five (33%), SSI in six (40%) and SAP in two (13%) infants. Infants with ALTE as compared to non-ALTE, have a significantly higher number of RE (104 vs. 71; p < 0.02), non-acid RE (74 vs. 35; p < 0.007) and a longer non-acid GER (1596 vs. 526 ; p < 0.01). Conclusion. Our data show that infants with ALTE have a higher nonacid reflux as compared to non-ALTE infants and that in our experience GER may be implicated in the pathogenesis of ALTE in two (13%) cases (95% CI 7–26%). doi:10.1016/j.dld.2007.07.061

A53

CO 11 COMBINED MULTICHANNEL INTRALUMINAL IMPEDANCE (MII) AND PH MONITORING IN THE EVALUATION OF GASTROOESOPHAGEAL REFLUX (GER) IN SYMPTOMATIC PRETERM NEWBORN L. Corvaglia, E. Mariani, A. Aceti, B. Battistini, M. Ferlini, G. Faldella Istituto Clinico di Pediatria Preventiva e Neonatologia – Policlinico Sant’Orsola-Malpighi – Universit`a di Bologna, Italy Aims. GER is common in preterm newborn, due to some promoting factors such the almost fixed lying position, the large fluid enteral intake, the frequent nurse handling and the use of permanent feeding tubes. Twentyfour-hour pH monitoring has traditionally represented the gold standard for GER detection: it recognizes GER episodes as a pH drop <4 and is able to indicate their duration and frequency. The instrument’s software can also calculate RipH (percentage of time during which pH is <4), which represents a good index of the exposure of oesophageal mucosa to gastric acidity. The major limit of pH monitoring is that it cannot identify non-acid GER episodes: this is relevant in the evaluation of GER in preterm newborn, because milk feeding buffers gastric pH for a long time after meal; moreover, pH monitoring does not give any information about physical composition of refluxate and is not able to describe bolus movement inside the oesophagus. MII is a new technique which is able to detect GER episodes as electrical impedance changes occurring inside oesophageal lumen. A GER episode can be recognized by MII only if it reaches at least two consecutive dipoles on the catheter (about 4–4.5 cm above LES) and for this reason it is unable to identify short segment non-acid episodes. It can also distinguish retrograde movement (GER) from antegrade movement (swallow) and identify the height reached by each GER episode above LES. Combined MII-pH monitoring allows the detection of both acid and non-acid GER episodes and for this reason it can be useful in preterm newborn whose gastric pH is often buffered by frequent milk meals. We aimed to describe GER features in preterm newborns with symptoms of GER, highlighting differences in GER detection between MII alone and combined MII-pH monitoring. Methods. Fifty-three preterm newborns (mean GE 29 weeks, range 24–33 weeks; mean BW 1274 g, range 500–2250 g) having GER symptoms (frequent regurgitations and/or post-prandial desaturations) underwent 24-h recording of simultaneous MII and pH monitoring. For each infant, we calculated the number and the duration of GER episodes detected by both pH monitoring and MII: MII-detected episodes were then divided into acid and non-acid according to pH value. Results. The mean number of pH-detected episodes was 54.68; a mean of 53.13 episodes was detected by MII (acid: 12.85; non acid: 41.83). Mean acid oesophageal exposure was 11.23% (0.45% detected by MII and 10.79% by pH monitoring), while mean non-acid oesophageal exposure was 1.99% (detected only by MII). Conclusions. Combined MII-pH monitoring seems to be the best choice to diagnose GER in preterm newborn, allowing the detection of a significantly higher number of GER episodes (mean 112.87) than MII alone. Combined MII-pH monitoring can detect all the acid episodes: long-segment acid GER are detected both by MII and pH monitoring, while short-segment acid GER are identified only by pH monitoring. MII monitoring can also recognize long-segment non-acid episodes, which are frequent in milk fed infants; the major limitation of this technique is that it is unable to detect short segment non-acid episodes. This limitation is particularly relevant in preterm newborn, whose oesophageal length is usually between 6 and 10 cm: for this reason, the incidence of non-acid episodes and the exposure of distal oesophageal mucosa to non-acid GER risk to be significantly under considered. For this reason, in preterm newborn we suggest the combined use of MII and pH monitoring, we also wish that MII software will be further improved to be able to detect also short segment non-acid episodes, whose correlation with acute events such as apnoeas and desaturations is still uncertain. doi:10.1016/j.dld.2007.07.062