Temporal association of polysomnographic cardiorespiratory events with GER detected by MII-pH probe in the premature infant at term

Objectives: The aim of the study was to examine temporal association (TA) between polysomnographic cardiorespiratory (CR) events and gastroesophageal reflux (GER) in premature infants with persistent CR events at >39 weeks postmenstrual age and determine whether the use of multichannel intraluminal impedance (MII)-pH probe improves sensitivity of the TA compared with pH probe alone. Patients and Methods: Seven infants born between 24 and 29 weeks' gestational age with persistent CR events at 39 to 48 weeks' postmenstrual age underwent a polysomnography with MII-pH probe. Symptom index (SI) and symptom-associated probability were calculated for diverse types of reflux and CR events. SI and a Fisher exact test with variable association windows were calculated for obstructive apnea (OA). Odds ratios for an OA given a reflux event and for a reflux event given an OA were determined. Results: With a Fisher exact test, a subject-specific association between MII events and OA was found in the 3 patients who required a fundoplication or had the worse clinical GER. Some level of TA was found with SI and symptom-associated probability in 6 of 7 infants. Association was found for pH >4 and pH ≤4 reflux events. pH-only events with no change of MII had only a limited role in generating CR events. Conclusions: TA between CR events and GER was found in a single-subject-level analysis in some infants with persistent CR events at term. This TA suggests a causal relation between CR and reflux events that was further strengthened by the clinical outcomes of each infant.