What Is the Aerodigestive Tract? And What Does It Have To Do With Respiratory Reflux?

Respiratory Reflux, especially Silent Nocturnal Respiratory Reflux (SNoRR) is the most misunderstood and important public health problem of our time. Since the reflux occurs at night without awakening the sufferer and there is no heartburn or indigestion during the day, this defines “Silent” Reflux. 

To understand Respiratory Reflux, you need to know that the digestive tract is connected to the respiratory tract, and how they join in the pharynx (throat) is pivotal. This post explains the Aerodigestive Tract and what can go wrong and why … to cause acid reflux. 

What Is The Digestive Tract?

The function of the Digestive (aka Gastrointestinal) Tract is to provide nutrition for the body. Absorption of nutrients happens in the Lower Digestive Tract, the intestines. When it comes to respiratory reflux, it is the Upper Digestive Tract that matters; and it includes the oral cavity (mouth), pharynx, Upper Esophageal Sphincter (UES), esophagus, Lower Esophageal Sphincter (LES), and stomach. It is useful to understand swallowing because reverse-swallowing is reflux (backflow). 

First, the mouth breaks up the food, adds saliva, and forms a bolus (ball). The tongue then pushes the bolus down and the pharynx contracts. At the same time, the larynx elevates and the vocal cords close tightly to prevent aspiration. When the bolus reaches the bottom of the pharynx, the UES opens and the bolus passes into the esophagus, which conveys the it to the bottom of the esophagus, through the LES, and into the stomach. 

The LES has to open and allow the food to enter the stomach, but once the LES closes, it should remain closed. If it opens later allowing stomach contents to go back up into the esophagus … that is gastric reflux … and if the refluxate goes all the way up and breaches the UES, then you’ve got respiratory reflux. 

What Is The Respiratory Tract?

When you think of the respiratory tract, you probably just think about breathing, but the respiratory tract also includes the mouth, pharynx (throat), larynx, vocal cords, nose, sinuses, ears, and airways such as the trachea and bronchi, as well as the lungs. 

Inside the lungs, the bronchi get smaller and smaller ending at the alveoli. These tiny, balloon-shaped structures expand during inhalation, taking in oxygen, and shrink during exhalation, exhaling carbon dioxide. this is the primary function of the respiratory tract/

What Is the Aerodigestive Tract?

The Aerodigestive Tract (ADT) is made up of the respiratory and digestive tracts together, treated as a single functioning unit; they are anatomically connected in the pharynx, and in addition, share the same nerve, the Vagus Nerve.  

The Big Influencer Is The Pharynx. Essential for both breathing and swallowing, the pharynx is part of the respiratory tract and part of the digestive tract. The shared pharynx is ground-zero for respiratory reflux.

The orange is respiratory reflux, the refluxate going everywhere, into the nose, sinuses, larynx, pharynx, and even through the vocal cords and into the lungs.   

The purpose of the Upper Esophageal Sphincter (UES) ― located at the top of the esophagus and bottom of the pharynx ― is to prevent gastric reflux from entering the airway. Indeed, when the UES opens when it shouldn’t, Respiratory Reflux results. (Of course, this implies that there also is trouble in the esophagus and the LES. Reflux causes reflux. As inflammation snow-balls, the valves and esophagus get increasingly ineffective.) 

The other pharyngeal  “valve,” the vocal cords, protects the lungs. The vocal cords function like a drawbridge, open for breathing and closed for swallowing. However, if reflux goes “down the wrong pipe” into the trachea, bronchi and lungs, aspiration pneumonia can result. Meanwhile, chronic microaspiration can cause COPD, chronic bronchitis, and cough.  

The laryngeal valve also can malfunction due to primary vocal cord problems. For example, if the cords cannot close due to vocal cord paralysis, then aspiration may be a chronic problem. To a lesser extent the vocal cords normally are thinner and weaker in the elderly making respiratory reflux aspiration during sleep potentially life-threatening.  

Why Doesn’t My Doctor Know About This? 

The medical specialties that “share” the aerodigestive system (e.g., otolaryngologists, gastroenterologists, pulmonologists, allergists, primary care physicians, and critical care specialists) cannot see the forest for the trees. Overspecialization and fragmentation of the ADT into anatomic subunits have resulted in general medical ignorance about respiratory reflux. 

How is it possible that respiratory reflux, especially silent reflux is invisible, unrecognized, and misdiagnosed by most physicians? Here’s why. The heavily defended GI model of reflux is only about heartburn, indigestion, and the esophagus. So, if the “go-to” doctor for “acid reflux,” the gastroenterologist, is clueless when it comes to respiratory reflux … having no test or treatment for it … then the negative consequences reverberate across the healthcare system. 

To make matters even more controversial, it appears that for fifty years the GIs have actively fought against the whole idea of  respiratory reflux … the GI heartburn business model of reflux is dead wrong. Heartburn, indigestion, and the esophagus (GERD) are small potatoes compared to respiratory reflux. If respiratory reflux is the main acid reflux disease, the the GIs deny it …. because it’s about money!

And the trickle down is that your specialist doctors probably have no idea about respiratory reflux either; it’s just not in their curricula. When it comes to common ADT conditions today? The specialist model of American medicine has failed.  Otolaryngologists, gastroenterologists, pulmonologists, allergists, primary care physicians, and critical care specialists do not understand or recognize respiratory reflux and ADT Medicine. 

Someday, Primary Care Physicians or some other basic healthcare professionals such as Physician Assistants or Nurse Practitioners, will be trained in Integrated Aerodigestive Medicine. That means that one healthcare provider will diagnose and treat all common ADT diseases, e.g., post-nasal drip, sinusitis, laryngitis, asthma, acid reflux, shortness of breath, chronic cough, etc. … and they will consult specialists only when needed. 

Pearl of the Week: Nuts

The best, least likely to cause reflux nuts are almonds, pistachios, and walnuts; the worst are chashews and macadamia nuts … cashews are the worst. Meanwhile, the Peanut, peanut butter, is a popular food item, is in the middle ground but should be avoided during Reflex Detox. It can be cautiously reintroduced when your reflux is under control.

Resources

If you would like to schedule a virtual consultation with me, Book Online. For more information about diagnosis and treatment of respiratory reflux, see my two companion books on Amazon: Dropping Acid: The Reflux Diet Cookbook & Cure and Dr. Koufman’s Acid Reflux Diet, and for chronic cough: The Chronic Cough Enigma.