Esophageal Manometry During Recovery From Endotracheal Intubation

Overview

1. An intact pharyngoesophageal reflex is essential to protect the upper airway from aspiration of either mouth contents or regurgitated gastric refluxate. This reflex is essential at protecting the airway in all patients. 2. In patients, while under medication to tolerate endotracheal intubation, it is postulated that an identifiable upper esophageal sphincter and esophageal peristalsis are not present. 3. With the cessation of anesthetics, accompanied by the reversal of nerve block, normal pharyngoesophageal peristaltic activity correlates with awakening the patient from anesthesia. This would be identified by the performance of esophageal manometry. 4. A return of normal verbally stimulated pharyngoesophageal swallowing sequence accurately identifies a safe time to remove endotracheal tubes and/or reverse anesthesia. This verbally stimulated swallowing sequence correlated precisely with the return of objective pharyngoesophageal function.

The emergence from routine general deep anesthesia with an endotracheal tube is a potentially dangerous time for patients. Patients cannot reliably maintain competence of the upper esophageal sphincter, thus aspiration of the contents from the mouth or regurgitated material from the stomach can be aspirated into the lungs leading to serious complications. In normal awake individuals the upper esophageal sphincter (also known as the cricopharyngeus or the inferior pharyngeal constrictor) is contracted and relaxes precisely timed with voluntary or involuntary swallowing. The swallowing sequence in normal awake persons begins with 1) the contraction of the upper and middle pharyngeal constrictors, 2) the posterior movement of the tongue and 3) the prompt relaxation of the contracted upper esophageal sphincter. Peristalsis then begins in the body of the esophagus leading contents to the stomach. The above is the normal sequence in humans, a process which maintains absolute separation of the airway and digestive passageways despite being in intimate proximity. During the early period of emergence from anesthesia, the aspiration risk is highest due to the sluggish return of the resting pressure in the upper esophagus and the lack of normal coordination with involuntary swallowing. Thus patients can't protect their airway by maintaining competence and appropriate relaxation of the upper esophageal sphincter. Routine high resolution solid state manometry is a standard routine technique is currently performed in awake patients sitting upright voluntarily requested to swallow small boluses of liquid. The entire sequence of events is studied using high resolution solid state manometry.