End Expiration Is More Accurate than Mid Respiration in Measuring Lower Esophageal Sphincter Pressure

Abstract

Background/Aims: Two ways popularly used to measure lower esophageal sphincter pressure are the mid-respiratory and end-expiratory methods. The aim of this study was to compare the suitability of these methods in the manometric assessment of patients with endoscopically documented esophagitis. Methods: Manometry was performed on 22 consecutive patients to determine whether medical therapy or surgery was the more appropriate treatment strategy. Lower esophageal sphincter pressure was measured during a slow station pull-through. End-expiratory lower esophageal sphincter pressure was assessed by measuring the highest trough which coincided with end expiration. Mid-respiratory lower esophageal sphincter pressure was assessed by bracketing the highest pressure over ≥3 respiratory cycles and measuring the mid point. Results: Mid-respiratory lower esophageal sphincter pressure (25.6 mm Hg) was higher (p < 0.0001) than end-expiratory lower esophageal sphincter pressure (15.7 mm Hg). Nine (41%) end-expiratory lower esophageal sphincter pressures were abnormally low (i.e., <10 mm Hg), whereas three (14%) mid-respiratory lower esophageal sphincter pressures were abnormally low (i.e., <14 mm Hg; p = 0.042). Conclusion: Mid-respiratory lower esophageal sphincter pressure measurement includes respiratory artifact and does not accurately measure lower esophageal sphincter pressure. End-expiratory sphincter pressure better identifies potential surgical candidates.

Effects of different respiratory maneuvers on esophageal sphincters in obese patients before and during anesthesia

“…This study has demonstrated that the LES pressure is lower during end‐expiration compared with inspiration during spontaneous breathing in awake, obese individuals. This is in agreement with results from studies in normal‐weight patients 3 . Consequently, it would seem relevant to use end‐expiratory values for LES measurements in order to record the lowest pressure.…”

“…Authors of gastroenterological studies recommend measuring the LES pressure during expiration based on the variation in the esophageal pressure during respiration 3 . In most anesthesiology reports, no data are presented regarding the phase of the respiratory cycle in which the measurements have been carried out.…”

Inspiration closure reflex: The effect of respiration on intrinsic sphincters

“…The degree of intrinsic sphincter closure appears to vary with the rate, depth, or volitional modification of inspiration. The LES and IUS pressure responses seen in this study appear similar to the “respiration artifacts” in other studies . It is possible that the IUS closure and pressure elevation related to inspiration could give a structural advantage at the neck of the urinary bladder to prevent incontinence (Fig.…”

“…Previous work has referred to transient relaxation or inhibition of the LES in association with swallowing, obstructive sleep apnea, mechanical ventilation, and a negative pressure body ventilator . In previous animal and human studies, respiration pressure “artifacts” in the LES and IUS were not noted or were electronically filtered by manometry instruments . There may be respiratory influences on intrinsic sphincter function that have not been adequately evaluated.…”

Effect of transnasal humidified rapid-insufflation ventilatory exchange on gastric insufflation during anaesthesia induction

“…17 With the mouths closed, increasing flow rates demonstrated nonlinear increases in airway pressure but airway pressures remained below 10 cmH 2 O even with flow rates up to 80 l min À1 . 17 As the threshold pressure to overcome the LOS is approximately 15 to 25 mmHg (20 to 34 cmH 2 O), 18 the increase in upper airway pressure by the THRIVE technique should be insufficient to induce gastric insufflation with its attendant risk of subsequent regurgitation.…”