PREVENTION OF MIDDLE EAR BAROTRAUMA If you find the topic interesting, please feel free to save it to a file or print it out for later reference. This document may be reproduced for personal or classroom use but please let readers know where it came from. There is also a video lecture of this material. Copyright (c) 1997 - 2000 Edmond Kay, M.D. TABLE OF CONTENTS Introduction Learning Objectives Relevant Anatomy What is Ear Fear? The Simplest Technique Assessing Equalization Efforts The Valsalva Maneuver The Frenzel Maneuver The Toynbee Maneuver Beance Tubaire Volontaire (BTV) The Roydhouse Maneuver The Edmonds Technique The Lowry Technique The Twitch The Take Home Message Summary Where to Get More Information INTRODUCTION Middle ear barotrauma is the most frequent diving injury I see in my medical practice. It occurs much more commonly in the novice diver as a direct result of improper middle ear equalization technique. The following information is intended for the diving instructor, diving safety officer and any individual charged with the responsibility of managing novice divers. This information should also be of value for the advanced or commercial diver interested in rapid descent. The topic includes a discussion of nine different techniques of equalization, and offers tips on assessing the effectiveness of middle ear pressurization. LEARNING OBJECTIVES At the end of this topic, the reader should be able to: 1. Define and recognize "Ear Fear". 2. Recognize and assess the effectiveness of equalization efforts. 3. Discuss the difference between middle ear pressurization and middle ear equalization. 4. Describe and be able to teach nine different methods of middle ear equalization. 5. Describe the medical conditions that might interfere with adequate middle ear equalization, and understand the appropriate use of decongestants. 6. Describe the conditions or injuries that would preclude further diving until medical clearance is obtained. Table of Contents RELEVANT ANATOMY The Eustachian tube was first identified by Bartolomeo Eustachio (Latin: Eustachius), an Italian anatomist who died in the 1500's. In the United States the Eustachian tube is usually pronounced "yoo-sta-shan", but some pronounce it "yoo-sta-ke-an" in honor of the anatomist as it more closely approximates the original Latin pronunciation of the name. The tube is approximately 1.5" long and is located in the back of the nasopharynx at approximately nostril level. The tube is normally closed and has a highly variable patency. This means that some individuals will virtually never have problems with middle ear equalization while diving. Others with narrow or partially obstructed Eustachian Tubes may have trouble equalizing their middle ears in airplanes or elevators. These later individuals can dive safely, but for them middle ear pressurization requires meticulous attention to detail and much practice. Thanks to the comments of Francisco Javier Orellana Ramos, a Diving Medical Officer from Spain, I am reminded that there are several factors that influence tubal patency and tolerance to pressure changes. The Eustachian Tube angle and the shape of the tube can affect ones ability to pressurize the middle ear. Individuals with a relatively large volume of air in the mastoid sinuses will be less tolerant to pressure changes as the actual volume change in the middle ear will be greater for a given amount of descent. Allergies, trauma, infection and Thyroid disorders are other possible causes of disruption in normal tubal function. For individuals who have difficulty pressurizing ears, the position in the water column is extremely important. It is well known that the head-down position during descent can make middle ear equalization more difficult. Less well understood is the reason for this effect. There are soft tissues in the nasopharynx which surround the membranous Eustachian Tube, and no doubt gravity plays a role in there normal functioning. The most likely candidate for positional obstruction is this soft tissue. A sub-optimal position can compromise marginally patent Eustachian Tube. For this reason it is advisable for students to begin descent slowly, and always in the head up position. Divers with prior ear problems, timid divers and those who are not sure whether middle ears will equalize should also assume this position. Half of the Eustachian Tube is surrounded by bone but the other half is open to the pressure changes of the respiratory system (ambient pressure). This membranous later half is partially surrounded by a "C" shaped cartilage and during swallowing, muscles of the soft palate pull on the Eustachian Tube. This traction opens the tube while closing the nasopharynx. The act of swallowing often causes a clicking or crackling sound to be heard and this sound is the noise made when the moist tissues of the Eustachian Tube pop open. You can hear this sound for yourself in a fellow diver or student by applying a stethoscope in the area around the ear. If the student swallows and the crackling sound is heard, the listener can verify that the Eustachian tube has opened. This technique was first described by Joseph Toynbee in the 1800's, and will be described later. Table of Contents WHAT IS "EAR FEAR"? Ear Fear is a term I have coined to describe the apprehension associated with middle ear equalization. It tends to occur in individuals who have had prior middle ear trauma, a frequent childhood history of middle ear infections or those who just get queasy when they feel new bodily sensations. To some, this sensation of pressure in the middle ears and the crackling in one's head associated with the popping open of a Eustachian tube is uncomfortable. These are the individuals who do not like to "pop" their ears and many have been told all their life that this is "bad to do". For these individuals, middle ear pressurization effort is anxiety provoking and efforts tend to be very cautious and tentative. For many of these novice divers, middle ear trauma occurs at the first dive. Students can become confused about the actual pressure needed to achieve middle ear equalization when well meaning friends remind them not to blow too hard. This advice is certainly prudent when a student is under water and experiencing middle ear squeeze. Unfortunately, for the squeamish individual, and especially if a marginally patent Eustachian tube is present, this limits the ability of some to pressurize adequately at anytime during the dive. Pressurization of the middle ear can and should be vigorous on the surface, when no negative pressure gradient is present across the middle ear. This means that it is possible (and desirable) for an individual to pre-pressurize the middle ear and to inflate the Eustachian tube prior to descent. Pressurization of the middle ear provides a pillow of air behind the tympanic membrane, protecting the "ear drum" (TM) from barotrauma." As descent occurs, more air can easily enter an inflated Eustachian tube and pass into the middle ear, if pressurization begins early in the dive. If the Eustachian tube is allowed to collapse at any time during descent due to squeeze, the pressure to re-inflate it becomes greater. For this reason, I always recommend that individuals practice pressurization of their middle ears prior to diving in order to test their Eustachian tubes for patency, and to perform middle ear pressurization before beginning actual descent to cushion the ears against trauma.. Table of Contents ASSESSING EQUALIZATION EFFORTS Before teaching pressurization techniques, it is useful to learn a technique for assessing the adequacy of pressurization. A technique I use in my office is to "watch the nose inflate" (Watch the Schnazolla). Inflation can be observed if one pinches the nasal passages (nares) closed, with pinching fingers held low on the nose. With fingers occluding the nares, observe the fleshy portion of the nose immediately above the fingers. A good, strong pressurization effort will cause the tissues above the occluding fingertips to balloon outward. This nasal inflation is an indication of the inflation effort (nasopharyngeal pressure) that has been applied to the Eustachian tubes. This can be practiced in the mirror in order to optimize technique. Merely pressurizing the nose is not quite the same as inflating the middle ear, but if the diver reports no evidence of a popping or crackling sensation the instructor may check the pressure of the nose to evaluate inflation effort. Practicing on yourself allows some comparisons of effort (and pressure) to be made. Table of Contents THE SIMPLEST TECHNIQUE Among the simplest and most basic techniques in diving are the yawn, swallow, jaw thrust and the head tilt. These techniques of equalizing middle ears are useful for individuals who have widely patent Eustachian tubes and never have problems with equalization. These methods hardly ever work alone without the addition of pressurization in an individual with marginally patent tubes. I do not recommend these techniques for the novice diver as they offer little margin for error. The first dive in a swimming pool is often the cause of significant barotrauma due to a combination of poor technique, student distraction and other factors such as buoyancy control. Pressurization techniques (see below) should ALWAYS be used first, until a student is comfortable with a preferred technique that reliably prevents middle ear squeeze. Table of Contents THE VALSALVA MANEUVER (pressurization) Antonio Valsalva lived in the 1700's and was the first to record a technique for pressurization of the middle ears. With the nostrils pinched closed, pressure is increased in the chest. An attempt is made to blow out the closed nostrils and cheek muscles are kept tight and retracted, not puffed out. With this technique, gradients of 6-10' of seawater can be achieved. This technique does have some disadvantages however as prolonged effort can cause venous engorgement of the tissues around the Eustachian tubes.