Anxiety can significantly explain bolus perception in the context of hypotensive esophageal motility: Results of a large multicenter study in asymptomatic individuals.

BACKGROUND: Previous studies have not been able to correlate manometry findings with bolus perception. The aim of this study was to evaluate correlation of different variables, including traditional manometric variables (at diagnostic and extreme thresholds), esophageal shortening, bolus transit, automated impedance manometry (AIM) metrics and mood with bolus passage perception in a large cohort of asymptomatic individuals. METHODS: High resolution manometry (HRM) was performed in healthy individuals from nine centers. Perception was evaluated using a 5-point Likert scale. Anxiety was evaluated using Hospitalized Anxiety and Depression scale (HAD). Subgroup analysis was also performed classifying studies into normal, hypotensive, vigorous, and obstructive patterns. KEY RESULTS: One hundred fifteen studies were analyzed (69 using HRM and 46 using high resolution impedance manometry (HRIM); 3.5% swallows in 9.6% of volunteers were perceived. There was no correlation of any of the traditional HRM variables, esophageal shortening, AIM metrics nor bolus transit with perception scores. There was no HRM variable showing difference in perception when comparing normal vs extreme values (percentile 1 or 99). Anxiety but not depression was correlated with perception. Among hypotensive pattern, anxiety was a strong predictor of variance in perception (R2 up to .70). CONCLUSION AND INFERENCES: Bolus perception is less common than abnormal motility among healthy individuals. Neither esophageal motor function nor bolus dynamics evaluated with several techniques seems to explain differences in bolus perception. Different mechanisms seem to be relevant in different manometric patterns. Anxiety is a significant predictor of bolus perception in the context of hypotensive motility.

Maturation of the rectoanal inhibitory reflex in very premature infants.

OBJECTIVE: To characterize anal sphincter function in very premature infants < or =30 weeks' postmenstrual age (PMA) and to evaluate the time of maturation of the rectoanal inhibitory reflex (RAIR) by using a sleeve catheter. STUDY DESIGN: Anorectal manometry was performed in 16 healthy neonates (nine girls) with a mean PMA of 29 weeks (range, 27-30 weeks) and a birth weight of 640 to 1590 g (median, 1220 g) with a micromanometric assembly (outer diameter, 2.0 mm). The assembly incorporated a 1.5-cm-long sleeve sensor for measurement of resting anal sphincter pressures and relaxation, and four side holes recorded anal and rectal pressures. Rectal distention was performed with direct air insufflation to elicit the RAIR. RESULTS: The mean anal sphincter pressure, rectal pressure, and anal sphincter oscillation frequency were 24.5+/-11.4 mm Hg, 6.5+/-4.8 mm Hg, and 11.1+/-2.3/min, respectively. A normal RAIR could be elicited in 13 (81%) infants studied. In two infants, the RAIR could not be elicited because of a low anal sphincter pressure of only 5 mm Hg. In the other child, no RAIR was seen despite the repeated insufflation of at least 5 mL of air. CONCLUSION: The majority (81%) of premature infants older than 26 weeks' PMA have normal anorectal pressures and a normal RAIR.

Characterization of anorectal pressure and the anorectal inhibitory reflex in healthy preterm and term infants.

OBJECTIVES: To evaluate anorectal motor function in healthy premature and term infants with the use of micromanometric techniques. STUDY DESIGN: Anorectal manometry was performed in 22 healthy neonates (9 female) with a mean postmenstrual age of 32 weeks (range, 30 to 38 weeks) with a micromanometric anorectal assembly (od 2.0 mm). The assembly incorporated a 2-cm-long sleeve sensor for measurement of resting anal sphincter pressures and relaxation, and 4 sideholes recorded anal and rectal pressures. Rectal distension was performed with a latex balloon or direct air insufflation to elicit the anorectal inhibitory reflex (AR). RESULTS: The mean anal sphincter pressure, rectal pressure, and rhythmic wave frequency were 40 mm Hg (range, 7 to 65 mm Hg), 11 mm Hg (range, 1 to 27 mm Hg), and 10/min (range, 8 to 14/min), respectively. A normal AR could be elicited in 21 of the 22 infants studied. CONCLUSION: An anorectal micromanometric sleeve catheter is suitable for use in evaluating anorectal pressures in preterm and term neonates. Insufflation of air without the use of a balloon to elicit the AR is reliable and suitable for use in infants <34 weeks. Premature infants older than 30 weeks' postmenstrual age have normal anorectal pressures and a normal AR.

Characterization of esophageal body and lower esophageal sphincter motor function in the very premature neonate.

OBJECTIVES: To characterize esophageal body and lower esophageal sphincter (LES) motor function in very premature infants. STUDY DESIGN: Esophageal manometry was performed in 12 very premature infants of 26 to 33 weeks' postmenstrual age (PMA) (body weights of 610-1360 g). Esophageal motor patterns were recorded for 30 minutes with a perfused micromanometric sleeve assembly (outer diameter, 2.0 mm). RESULTS: Esophageal pressure waves triggered by dry swallows were predominantly (84%) peristaltic in propagation sequence. All infants showed tonic LES contraction; the mean resting LES pressure (LESP) for individual infants ranged from 5.0 +/- 4.1 mm Hg to 20.0 +/- 4.8 mm Hg. In all infants the LES relaxed (duration, 5.8 +/- 3.0 seconds; nadir pressure, 1.8 +/- 2.6 mm Hg) in response to pharyngeal swallows. Transient LES relaxations (TLESRs) (duration, 21.7 +/- 8.7 seconds; nadir pressure, 0.1 +/- 1.8 mm Hg) occurred on average 2.6 +/- 1.6 times per study; 86% of these relaxations triggered esophageal body common cavity events known to be associated with gastroesophageal reflux. CONCLUSIONS: Esophageal motor function is well developed in very premature infants. Our data also suggest that TLESR is the predominant mechanism of reflux in these babies.

Lower esophageal sphincter position in premature infants cannot be correctly estimated with current formulas.

OBJECTIVES: Strobel's formula (Esophageal length = 5 + 0.252 x Height) is frequently used as a guide for determining the distance from the nares to the lower esophageal sphincter (LES) in term infants. The aim of this study was to examine this relationship in premature infants. STUDY DESIGN: The distance from nares to LES was manometrically determined in 156 premature infants (26-40 weeks' postmenstrual age; body weights of 610-3050 g). The ability of body weight, height (body length), head circumference, and postmenstrual age to predict the manometrically determined LES position was evaluated with linear and non-linear regression analyses. RESULTS: Body weight and body length were the most predictive of distance from nares to LES (r(2) = 0.848 and 0.802, respectively). These relationships were non-linear and, in the case of body length, deviated substantially from Strobel's model. CONCLUSIONS: In premature neonates, a different formula is needed for prediction of the distance between nares and LES than that applied to term infants and children.

Mechanisms of gastroesophageal reflux in healthy premature infants.

OBJECTIVES: The aim of this study was to characterize the motor events responsible for gastroesophageal reflux (GER) and esophageal acid clearance in a cohort of healthy preterm infants. STUDY DESIGN: Esophageal motility was recorded for 2 to 3 hours after a feeding in 24 preterm infants, 31 to 38 weeks' postmenstrual age, by using a sleeveside hole micromanometric assembly incorporating a pH probe. RESULTS: Sixty acid GER episodes were recorded by pH probe, and 133 non-acid GER episodes were recorded manometrically by the presence of esophageal common cavities. Of the 193 GER episodes, 159 (82%) were associated with transient lower esophageal sphincter relaxation (TLESR). TLESRs were significantly longer in duration than single swallows (15.1 seconds vs 5.6 seconds, P < .001) and had lower nadir pressures (0.8 mm Hg vs 2.3 mm Hg, P < .001). A total of 3216 esophageal body pressure waves were analyzed; 70% of swallow-induced pressure waves were peristaltic in sequence compared with 5% of swallow-unrelated pressure waves. During periods of esophageal acidification (pH below 4), peristaltic esophageal body pressure wave sequences cleared acid refluxate more effectively than nonperistaltic pressure wave sequences. CONCLUSIONS: In healthy preterm infants, TLESRs are the predominant mechanism underlying GER, and esophageal clearance mechanisms are well developed by at least 31 weeks' postmenstrual age.