Читать книгу The Esophagus - Группа авторов - Страница 124

Tonic vagal excitation ensures significant but variable resting pressure in the closed UES [87], between 35 and 200 mmHg [79,88–90]. UES resting pressure is inconsistent due to its odd shape (see Figure 5.7). Further, reliable pressure measurements are difficult since the UES can move 2–3 cm during swallowing [79, 91], and the recording device itself may contribute to the measured pressure [87, 92, 93], with larger devices recording higher pressures [94, 95]. UES resting pressure decreases during sleep [96] and with anesthesia [97], which can reduce UES pressure to as low as 8 mmHg. UES pressure is higher during inspiration [92, 96,98–100], with coughing [101], and with stress [102, 103]. A number of reflex responses alter UES pressure, particularly to prevent reflux into the pharynx [104]. Pharyngeal HRM has improved the ability to monitor UES pressures and response during physiologic events such as swallowing and belching (see Figure 5.6).

Figure 5.5 Normal oropharyngeal swallow. (A) At rest the bolus is held in the mouth. (B) Bolus is conveyed into the oropharynx. The airway and surrounding larynx have been elevated. (C) Bolus is descending in advance of the descending peristaltic wave. The epiglottis is now horizontal, the larynx is maximally elevated, and the bolus passes into the hypopharynx. (D) Bolus continues to descend and begins to pass through the open upper esophageal sphincter (UES) into the esophagus, with the peristaltic wave descending behind it. The nasopharynx begins to open, and opening progresses in a descending sequence. (E) The pharyngeal contraction moves into the hypopharynx as the bolus continues through the open UES. The nasopharynx continues to open from the top. (F) Bolus is completely in the esophagus. The nasopharynx, pharynx, and entry to the airway have opened, although the larynx has not completely descended to its original position.

Source: Donner et al. [58] with permissions of Springer Nature.