Older Age Reduces Upper Esophageal Sphincter and Esophageal Body Responses to Simulated Slow and Ultraslow Reflux Events and Post-Reflux Residue

Abstract

Background & aims: It is not clear how age affects airway protective mechanisms. We investigated the effects of aging on upper esophageal sphincter (UES) and esophageal body pressure responses to slow and ultraslow simulated reflux events and post-reflux residue.

Methods: We performed a prospective study of 11 elderly (74 ± 9 years old) and 11 young (28 ± 7 years old) healthy volunteers. Participants were placed in a supine position and evaluated by concurrent high-resolution impedance manometry and an esophageal infusion technique. Potential conditions of gastroesophageal reflux were simulated, via infusion of 0.1 N HCl and saline. UES and esophageal pressure responses were measured during the following: slow infusion (1 mL/s) for 60 seconds, 60 seconds of postinfusion dwell period, ultraslow infusion (0.05 mL/s) for 60 seconds, and 60 seconds of a postinfusion dwell period. All infusions were repeated 3 times. We used the UES high-pressure zone contractile integral (UES-CI) to determine responses of the UES.

Results: Young and elderly subjects each had a significant increase in the UES-CI during slow infusions and during entire passive dwell intervals compared with baseline (P < .01, both groups). Ultraslow infusions were associated with a significant increase in UES-CI in only the young group, in the late infusion period, and into the dwell interval (P < .01). During the slow infusions and their associated dwell periods, young subjects had a higher frequency of secondary peristalsis than elderly subjects (P < .05). There was more secondary peristalsis during active infusions than dwell intervals. Secondary peristalsis was scarce during ultraslow infusions in both groups.

Conclusions: UES and esophageal body pressure responses to low-volume ultraslow reflux and associated post-reflux residue are reduced in elderly individuals. This deterioration could have negative effects on airway protection for people in this age group.

Keywords: Post-Reflux Period; Reflux; Secondary Peristalsis; Upper Esophageal Sphincter.

Conflict of interest statement

No financial or personal conflict to disclose

Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

Examples of UES contractile response to slow 1ml/s (1a) and ultra-slow 0.05ml/s (1b) acid and saline intra-esophageal infusions in young and elderly. As seen in figure 1a, in both age groups and for both types of infusions, UES contraction occurred shortly after the start of infusions and continued during the entire period of infusion. In addition, UES contraction was sustained after the active infusion ceased through the passive dwell time in which acid and saline residue remained in the esophagus as evidenced by the impedance signature. In contrast, as seen in Figure 1b, in both acid and saline infusions, significant increase in UES pressure was only observed in the young group and at the late stage of infusion which was sustained into dwell interval (also see figure 2 and 3). As seen there was no significant UES response noted in the elderly either during active infusion or passive dwell interval.

Figure 2

UES contractile response to slow (1ml/sec) and ultra-slow (0.05ml/sec) acid infusions in (2a) young and (2b) elderly. The X-axis displays each of the 10-second epoch before, during and after acid infusions. As seen in both young and elderly, the UES contractile response to slow acid infusion was significantly stronger than that of the ultra-slow infusion and the difference became notable starting at the second 10-second Epoch of infusion (p

Figure 3

UES contractile response to slow (1ml/sec) and ultra-slow (0.05ml/sec) saline infusions in (3a) young and (3b) elderly. The X-axis displays each of the 10-second epoch before, during and after saline infusions. As seen in both young and elderly, similar to acid infusion, the UES contractile response to slow saline infusion was significantly stronger than that of the ultra-slow infusion and the difference became notable starting at the second 10-second Epoch of infusion (p

Figure 4

UES pressure response to slow (1ml/sec) (4a) acid and (4b) saline intra-esophageal infusion in young and elderly. The average of 10-second epochs of UES-CI is presented. In acid infusion, both young and elderly showed significant increase in UES pressure during active acid infusion as well as during the passive dwell interval when compared to baseline. Similar to acid infusion, in saline infusion, both young and elderly also showed significant increase in UES-CI during active infusion and passive dwell interval. UES-CI: UES high-pressure zone contractile integral

Figure 5

UES pressure response to ultra-slow (0.05ml/sec) (5a) acid and (5b) saline intra-esophageal infusion in young and elderly. Average of 10-second epoch UES-CI is presented. In both acid and saline, significant increase of UES-Cl was only observed in the young group and at the late stage of infusion which was sustained into dwell interval (also see figure 2 and 3). There was no significant UES response noted in the elderly either during active infusion or passive dwell interval. UES-CI: UES high-pressure zone contractile integral

Figure 6

Comparison of development of secondary peristalsis during slow (1ml/sec) infusion and passive dwell interval in (6a) acid infusion and (6b) saline infusion. In both acid and saline, active infusions resulted in more secondary peristalsis than those observed in the dwell intervals. During the dwell period, young subjects exhibited higher percentage of infusions resulting in secondary peristalsis compared to the elderly.

Figure 7

Rate of secondary peristalsis (7a) and rate of esophageal non-peristaltic contraction (7b) during slow (1ml/sec) acid and saline infusion as well as during their associated dwell interval (Mean ± SD). As seen in 7a, young subjects showed a higher frequency of secondary peristalsis compared to the elderly in both active infusion and passive dwell interval. As seen in figure 7b, the elderly exhibited more frequent non-peristaltic esophageal contraction during both slow infusion and passive dwell compared to young subjects.