Heino Skopnik

Association of apnea and nonacid gastroesophageal reflux in infants: Investigations with the intraluminal impedance technique*

An association of apnea and gastroesophageal reflux (GER) was proposed previously. However, pH metry as the standard diagnostic tool for GER only measures acid reflux (pH < 4). It is difficult to interpret studies in infants with a presumed association between apnea and GER based on pH metry because the buffering effect of feeding may result in predominantly nonacid GER. The aim of this study was to investigate the temporal association of apnea and GER with the pH‐independent intraluminal impedance technique (IMP). Infants with recurrent regurgitation or respiratory symptoms suggestive of apnea were investigated simultaneously with IMP, pH monitoring, and polygraphy. IMP patterns, pH, oronasal flow, and chest wall movement were recorded and analyzed.

Randomized double-blind study of the nutritional efficacy and bifidogenicity of a new infant formula containing partially hydrolyzed protein, a high β-palmitic acid level, and nondigestible oligosaccharides

Objectives The aim of this study was to evaluate the nutritional efficacy and bifidogenic characteristics of a new infant formula containing partially hydrolyzed whey protein, modified vegetable oil with a high &bgr;-palmitic acid content, prebiotic oligosaccharides, and starch. Methods In a double-blind study, healthy formula-fed term infants aged younger than 2 weeks were randomized to receive either the new infant formula (NF) or a standard formula (SF) until the age of 12 weeks. Anthropometric measurements were taken at enrollment, 6 weeks, and 12 weeks. In a subsample of infants, blood samples were taken at 6 weeks and stool samples were taken at enrollment and 6 weeks. Blood samples were analyzed for biochemical measures of protein status and amino acids, and stools were analyzed for total bacteria and bifidobacteria. Mothers completed a feeding diary and questionnaire at 6 and 10 weeks. Results One hundred fifty-four infants were enrolled in the study; 102 completed the trial. The growth of infants in both formula groups was in line with published growth curves. During the first 6 weeks, NF girls gained more weight and head circumference than the SF girls. These velocity differences were not maintained throughout the 12-week study period. The NF stools had a higher proportion of bifidobacteria at 6 weeks compared with the SF stools, and they were softer. There were no clinically significant differences in the blood biochemical and amino acid values between groups. Both formulas were well tolerated by the infants. Conclusions When compared with a standard infant formula, the new formula supported satisfactory growth, led to higher counts of bifidobacteria in the feces, produced blood bio-chemical values typical of formula-fed infants, and was well tolerated.

Gastroesophageal reflux in infants : Evaluation of a new intraluminal impedance technique

In this study, pH metry was simultaneously applied with a new technique, the intraluminal multiple electrical impedance (IMP) procedure, for measuring gastrointestinal motility for gastroesophageal reflux (GER) detection. Seventeen infants with clinical symptoms of GER disease such as recurrent apnea, aspiration pneumonia, wheezing, and failure to thrive were investigated during two feeding periods. A single catheter combining a pH electrode with seven electrodes for impedance measurements over a distance of 8.5 cm was used for the investigation. In all patients, 185 acid episodes were detected by pH metry. In 106 of these 185 acid episodes, a unique pattern in the IMP readings was noted, indicated by a retrograde esophageal volume flow. These episodes were regarded as acid GER episodes. Seventy-one of the 185 acid episodes occurred during the clearance process of a preceding acid GER characterized by typical IMP readings of an anterograde bolus transport. Eight of 185 acid episodes were missed in the IMP readings for technical reasons. The IMP pattern described as characteristic for a GER was observed in 490 other episodes not detected by pH metry. More than 75% of all GER detected by IMP reached the pharyngeal space; 73% of all GER occurred during feeding and the first 2 postprandial hours and 27% occurred during the remaining time until the next feeding. Even during the latter period, 34% of GER were detected by IMP only; they were missed by pH metry. Volume clearance indicated by IMP was always completed earlier than acidity clearance. The results show that IMP technique facilitates the detection of all GER, whereas pH metry is confined to the measurement of acid GER. Therefore, this technique might improve the evaluation of GER disease and detection of GER in conditions with gastric hypoacidity.

Esophageal pH monitoring and impedance measurement: a comparison of two diagnostic tests for gastroesophageal reflux.

Background pH monitoring is the standard diagnostic tool for gastroesophageal reflux in infants. However, this method does not document the reflux of all kinds of fluid from the stomach into the esophagus, but only documents acid material. The parameters that define reflux episodes by pH monitoring have been derived empirically from observations of many infants considered healthy and ill. Acid reflux is a continuum, some reflux is normal and doubt exists as to how much reflux is abnormal. In this study, one of the standardized protocols for analyzing pH recordings was evaluated and compared with simultaneously obtained intraesophageal impedance measurement (IMP), a pH-independent method of detecting bolus movement within the esophagus. Methods The esophagi of 50 infants with reflux symptoms were measured, using both standard pH probe and multiple-site impedance measurement. A standard protocol for analyzing esophageal pH records was used. The sampling rate for pH values was 15/min. Acid reflux was defined as pH less than 4.0 (threshold pH) for at least 15 seconds (minimal duration) with at least 30 seconds (latency time) between separate episodes. The software used could adjust independently or in combinations the sampling rate and these reflux criteria. Thereby it was determined whether changes in the criteria for acid reflux improved the sensitivity and predictive value of pH monitoring when compared with reflux episodes defined by IMP. Results During 318 hours of recording in 50 infants, 1,887 episodes of reflux occurred according to IMP. Only 282 (14.9%) of the IMP-determined episodes were acid reflux episodes. No alkaline reflux episodes occurred. Among the 270 pH probe–determined episodes using the standard criteria of acid reflux, only 153 (sensitivity, 54.3%; positive predictive value, 56.7%) were accompanied by unmistakable retrograde bolus movement using IMP measurements. Retrograde bolus movement did not accompany the other 117 episodes. Using a sampling rate of 15/min, a pH threshold of 4.0, a minimal duration of reflux episodes of 8 seconds, and a latency time of 60 seconds, the positive predictive value of pH probe results increased to 60.7%. Variations in the sampling rate or criteria for defining acid reflux did not significantly improve the accuracy of the pH probe results versus IMP-defined episodes. Conclusions Most reflux episodes that occur in infants are undetectable by standard pH probe monitoring. pH monitoring does not detect all reflux in the esophagus but is useful for detecting acidity in the esophagus and determining the duration of its presence. Combining pH monitoring with impedance measurement is a valuable diagnostic tool for gastroesophageal reflux in infants.

Gastroesophageal reflux and respiratory phenomena in infants: status of the intraluminal impedance technique.

BACKGROUND The coincidence of recurrent respiratory symptoms and gastroesophageal reflux (GER) is a well-known phenomenon in infants. Twenty-four-hour pH metry is the presumed gold standard of diagnostic tools for this symptom complex, but with this method, only acid (pH <4) and alkaline (pH >7) GER can be detected. Gastroesophageal reflux with an esophageal pH in the physiological range (pH 5-6.8) may represent many cases of clinically relevant GER unrecognized by pH metry. In this study the intraluminal multiple electrical impedance (IMP) procedure for complete registration of GER was compared with pH metry for its diagnostic value in the presence of respiratory symptoms. METHODS Twenty-two infants with recurrent regurgitation or pulmonary problems were investigated simultaneously with IMP, pH metry, and polygraphy during two feeding periods. Heart rate, oxygen saturation, sleep states, and oronasal flow were recorded, among other parameters. RESULTS Three hundred sixty-four occurrences of GER were detected by IMP; only 11.4% had a pH less than 4 and were therefore recognized by pH metry. Three hundred twelve (84.8%) occurrences were associated with breathing abnormalities, and 11.9% of these were detected by pH metry. Nineteen instances were accompanied by a decrease of oxygen saturation of more than 10% of the initial value. Only three (15.8%) of these had a pH less than 4. The remaining 16 reflux episodes were recognized by IMP only. After software-aided preselection, 165 instances of apnea were visually validated, 49 of which were accompanied by GER. Thirty-eight (77.6%) of these were exclusively recorded by IMP. CONCLUSIONS The use of pH metry alone cannot detect most GER incidents accompanied by respiratory symptoms and therefore does not appear to be suitable for this approach. The pH-independent IMP technique promises to be a reliable tool for presumably GER-associated respiratory symptoms.

Inter- and intraobserver agreement in 24-hour combined multiple intraluminal impedance and pH measurement in children.

Objectives: Assessment of intra- and interobserver agreement in multiple intraluminal impedance (MII) measurement between investigators from different institutions. Methods: Twenty-four 18- to 24-hour MII tracings were randomly chosen from 4 different institutions (6 per center). Software-aided automatic analysis was performed. Each result was validated by 2 independent investigators from the 4 different centers (4 investigator combinations). For intraobserver agreement, 6 measurements were analyzed twice by the same investigator. Agreement between investigators was calculated using the Cohen kappa coefficient. Results: Interobserver agreement: 13 measurements showed a perfect agreement (kappa >0.8); 9 had a substantial (kappa 0.61–0.8), 1 a moderate (kappa coefficient 0.41 to 0.6), and 1 a fair agreement (kappa coefficient 0.11–0.4). Median kappa value was 0.83. Intraobserver agreement: 5 tracings showed perfect and 1 showed a substantial agreement. The median kappa value was 0.88. Conclusions: Most measurements showed substantial to perfect intra- and interobserver agreement. Still, we found a few outliers presumably caused by poorer signal quality in some tracings rather than being observer dependent. An improvement of analysis results may be achieved by using a standard analysis protocol, a standardized method for judging tracing quality, better training options for method users, and more interaction between investigators from different institutions.

Effect of Cisapride on Acid Gastro-Oesophageal Reflux during Treatment with Caffeine

About 50% of preterm infants and neonates receiving methylxanthines for respiratory stimulation will develop a pathological gastro-oesophageal reflux (GOR) pattern. In the face of potential GOR-related complications the effect of a concomitant treatment with a prokinetic agent, such as cisapride, should be evaluated. In this study 32 formerly preterm infants were studied simultaneously by 24-hour oesophageal pH monitoring and cardio-respirogram before the presumed end of caffeine treatment. In 14 of these infants a reflux index (RI; percentage of recording time) of more than 4% could be detected (pH <4). Ten of them were treated orally with cisapride (0.2 mg/kg t.i.d.). Data of pH monitoring, cardio-respirogram and caffeine serum concentrations were obtained before and 5 days after introducing cisapride. The RI and the frequency of GOR decreased significantly with cisapride. The steady-state serum concentrations of caffeine were not influenced by cisapride and the extent of periodic breathing remained unchanged. In conclusion, cisapride has a positive influence on GOR parameters during caffeine treatment without impairing the oral bioavailability or therapeutic effect of caffeine.

Gastroesophageal Reflux and Body Movement in Infants: Investigations with Combined Impedance-pH and Synchronized Video Recording

The aim of this paper was to investigate the temporal association of gastroesophageal reflux (GER) and body movement in infants. GER were registered by combined impedance-pH, documentation of body movement was done by video. Videorecording time (Vt) was divided into “resting time” and “movement time” and analyzed for occurrence of GER. Association was defined as movement 1 minute before/after the beginning of a GER. Statistical evaluation was by Fishers exact test. In 15 infants, 341 GER were documented during Vt (86 hours). 336 GER (99%) were associated with movement, only 5 episodes (1%) occured during resting time. Movement was significantly associated with the occurrence of GER (P < .0001). There is a strong temporal association between GER and body movement in infants. However, a clear distinction between cause and effect could not be made with the chosen study design. Combined impedance-pH has proven to be the ideal technique for this approach.

A Surprise during Pediatric Endoscopy

To the Editor: A 10-year-old boy was admitted to the hospital with crampy epigastric pain after eating. He mentioned swallowing a small object. Gastroscopy revealed a toy flashlight (2.5 cm in diameter) emblazoned with a cartoon character (Figure 1). The boys symptoms were relieved after the flashlight was removed, and his flashlight still worked.