The picturesque villages and towns around Pont du Gard delight the eye, and one in particular, Aramon, should be on the tip of every pitot’s tongue. No, not a typo; every pilot should know that Amaron was the 17th-century birthplace of Henri Pitot. He invented a means of measuring the flow velocity of water and, with a little adaptation, the pitot-static system was born when Frank Short in 1912 hooked a wing-mounted pitot-static head to a U-shaped manometer (the velometer), giving pilots a reliable air-speed indicator.
The concept of a Pitot tube exposed to ram-air, a static port relatively shielded from airflow, and related instruments provides us with information about airspeed, vertical speed, and altitude relying on air pressure gradients. We all know that an ice- or debris-blocked Pitot and drain tube is a nuisance, causing the impression that one’s airspeed is increasing while climbing, and decreasing while descending. A static port blockage from airframe icing or insects is more problematic as it will induce a frozen altitude and VSI, and dangerous issues with airspeed indication. Accidents from issues with Pitot-static systems include the Air France flight 447 disaster in 2009 and Aeroperú flight 603 in 1999, where the static port had been taped over for cleaning and waxing and not removed.
So now that I have your attention, would you be surprised to know that you have a similar system in your head? And if it gets blocked, while it may not cause you to effect controlled flight into terrain, it will induce confusion and pain, quite severe pain!
A 16th-century Italian anatomist, Bartholomaeus Eustachius, is credited with describing the tube leading from the inner ear to the throat, but careful historical review suggests others, all the way back to Aristotle, knew about it. The Eustachian tube is lined with cells that produce mucus and are capable of “sweeping” away fluid and debris. This tube is a bony canal in the skull in the outer part of the ear, and composed of cartilage in its inner part, opening behind where the nose meets the throat. It functions to equalize pressure inside and outside the ear, draining fluid that may accumulate and limiting bugs from nose or throat finding their way into the delicate ear structures and in fact is involved in many cases of otitis media, a significant ear infection.
As one descends during a scuba dive, external water pressure increases, forcing the eardrum inward, a painful sensation that is alleviated by pinching one’s nostrils and blowing out, thereby forcing air into the tube and balancing pressure on both sides of the eardrum. Additionally, there are four muscles involved in actively opening and closing the tube; the relevance of this will become clear shortly.
If one has an upper respiratory tract infection such as a common cold, or allergies, a stuffy nose, weepy eyes, sneezing, and coughing are common symptoms. Of course, one should self-ground until fully recovered, because any form of physical ailment affects cockpit performance. But there is another element to consider; the same inflamed membranes, weeping mucus from nose and throat, are up to no good in your Eustachian tube, impeding its function much like a blocked Pitot-static system. And if you choose to fly unwell, as pilot or passenger, instead of experiencing confusing readings from instruments you will experience extreme pain on ascent as air trapped inside your ear expands, and no amount of jaw wriggling or blowing out against closed nostrils will do the trick, and of course, you might infect other passengers. Symptomatic relief may be obtained with nasal steroid sprays to decrease inflammation, and sprays containing oxymetazoline might help, but flying when so affected is not a great idea. Oxymetazoline is found in many over-the-counter medications and works by forcing blood vessels in the nose to constrict. Extended application can actually worsen symptoms due to “rebound congestion,” so use sparingly.
Chronic problems in the absence of allergies may imply the tube is not functioning properly and may be physically blocked by something other than mucus. Reflux esophagitis, where acid comes up from the stomach, can enter the tube, irritating the membranes which then become inflamed. Swollen lymph nodes (adenoids) and tumors can present in this manner, and due to how serious the latter can be, if this problem develops and does not resolve, please see an ENT specialist. Less commonly, neurological diseases affect the muscles preventing proper Eustachian tube performance.
It is quite common to see a patulous or “floppy” tube that fails to open or close properly, causing fluid build-up and hearing one’s own voice or breathing quite loudly. People also experience a sense of “fullness,” and external sounds are muffled; these symptoms can be quite disorienting and unpleasant, but if one exhales against a closed nose, the symptoms abate. Common causes include losing weight, chronic allergies and reflux as above, stress, anxiety, and various neurological and immune illnesses. This can be diagnosed based on history and examination, but your ENT doctor may look at how your eardrum appears and moves, and may also measure pressure gradients. This is most often treated with nasal sprays and staying well-hydrated. Surgical options exist whereby the tube membrane can be treated with a KTP laser to remove florid internal tissue, excising the adenoids and stretching the tube with a balloon and possibly inserting a stent or tube to keep the Eustachian open.
If the problem only occurs during flight or scuba diving, it is known as a baro-challenge-induced Eustachian tube dysfunction, which would be a wretched diagnosis for anyone reading this column as it could limit time aloft.
And a note of caution: while ear wax is a common reason for muffled hearing, do not succumb to the temptation of putting a cotton wool-tipped probe in your ear! Wax is a natural defense, but if it becomes a problem, try warmed ear drops and then see your medical practitioner. There is an old adage among doctors; never put anything smaller than your elbow in your ear! In other words, never put anything in your ear!
Eustachian tube dysfunction is common and manageable; a few years back singer Celine Dion was diagnosed with this problem and continues to delight us. So, if your tube is behaving like a dodgy Pitot-static system, don’t get that sinking feeling; just as Celine sang in Titanic, your heart will go on and your flying will go on, just not when you are bunged up! Fly well!
Please check out my new podcast with my old medical school colleague and dear friend, Dr. Nigel Guest.
You can subscribe for free at www.jointhedocs.com
YouTube: @JoinTheDocs,
Instagram: @JoinTheDocs, TikTok: @JoinTheDocs, Facebook: @JoinTheDocs,
Twitter: @JoinTheDocs
....and on Spotify or Apple or wherever you get your podcasts @jointhe docs. I hope you enjoy!
You can send your questions and comments to Dr. Sackier via email: [email protected]
