for people ages 18-70 (full criteria)
at San Francisco, California
study started
completion around
Principal Investigator
by Stanley J Rogers, MD
Headshot of Stanley J Rogers
Stanley J Rogers



  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.


Motility Function, Extubation, Manometry, High resolution solid state manometry, Manometry Device


You can join if…

Open to people ages 18-70

  • Patients between 18 and 70 years of age (ASA I or II).
  • Already scheduled for endotracheal tube extubation.
  • Willing and able to give informed consent in either English or Spanish.

You CAN'T join if...

  • Pregnant, breastfeeding, or unwilling to practice birth control during participation in the study.
  • Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data.
  • Patients not meeting entry criteria above.
  • Refusal to give informed consent.
  • Coagulopathy (INR > 2 and/or platelet count < 100,000.
  • White Blood Cell count < 5,000/mm3
  • Arrhythmia
  • Serum creatinine > 2 mg/dl
  • Prior known or suspected nasal obstruction.
  • Known or suspected Zenker's diverticulum of esophagus, esophageal stricture, head/neck radiation therapy, hereditary telangiectasis, esophageal varices, cirrhosis.
  • Anticoagulant usage such as heparin or Plavix


  • UCSF
    San Francisco California 94143 United States

Lead Scientist at UCSF

  • Stanley J Rogers, MD
    Dr. Stanley J. Rogers is UCSF's chief of minimally invasive surgery. He directs the Bariatric Surgery Center and the program for treating liver tumors with radiofrequency thermal ablation (an image-guided procedure in which a needle is passed through the skin and heat is used to destroy the abnormal tissue).


not yet accepting patients
Start Date
Completion Date
University of California, San Francisco
Study Type
Expecting 100 study participants
Last Updated