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.
*Department of Pediatrics, Neonatology, Johns Hopkins Hospital and School of Medicine, Baltimore, USA
†Department of Pediatric Pulmonology and Sleep Medicine, Johns Hopkins Hospital, Baltimore, USA
‡Division of Pediatric Gastroenterology, Johns Hopkins University, the Mount Washington Pediatric Hospital, Baltimore, USA
§Scientific and Statistical Computing Core of the NIMH Intramural Research Program, Bethesda, Maryland, USA.
Received 2 September, 2009
Accepted 28 August, 2010
Address correspondence and reprints requests to Jeanne Nunez, MD, Johns Hopkins Bayview Medical Center Neonatal Intensive Care Nursery, AA2 Building, 4940 Eastern Ave, Baltimore, MD 21224-2780 (e-mail: firstname.lastname@example.org).
This work was supported by a Thomas Wilson grant.
Daniel Glen is affiliated with the National Institute of Mental Health, National Institute of Health, but has contributed to this article in a private capacity. The authors report no conflicts of interest. The views expressed in the article do not necessarily represent the views of NIH or the United States.