This article is more than 5 years old. Information may no longer be current.
Pneumatic otoscopy: An old diagnostic tool revisited
In one study of otoscopy use, only 21% of physicians always used it and 42% never used it.
Click Here to Manage Email Alerts
The Siegle diagnostic pneumatic otoscope head was invented and popularized by a German physician, Dr. Emil Siegle of Stuttgart, around the time of the American Civil War.
The Siegle otoscope design was a simple but brilliant modification of an older diagnostic otoscope. The modification consisted of a short, steel straw, capped by a hollow bulbous flange. The base of the tube was welded to the barrel of the otoscope head and a hole was drilled through the steel barrel in order to admit air under pressure into the chamber of the diagnostic otoscope head. One end of a rubber tube could be attached to the bulbous flange, and the opposite end of the tube was inserted into the examiner’s mouth just passed the alveolar ridge.
The purpose of the Siegle modification was to create a simple conduit for the application of air under pressure to evaluate the movement of the tympanic membrane while negative pressure followed in sequence by positive pressure was applied by the mouth (or could be applied via rubber bulb).
An aural speculum was originally permanently affixed to the open end of the barrel of the Siegle otoscope head. Later modification of the original Siegle design incorporated interchangeable aural specula, a magnifying lens and a battery-containing handle. The most recent major improvements in hand-held otoscopes include halogen and halogen HPX (high power xenon) bulb illumination, 3.5-volt nickel-cadmium or lithium rechargeable batteries and interposition of a rubber gasket between the sliding lens cap and the head of the otoscope to reduce air leaks.
The Welch-Allyn MacroView otoscope head promises 30% more magnification and an enhanced view of the entire tympanic membrane. One drawback to this excellent viewing diagnostic head is the poor design of the pneumatic part of the otoscope. It has a receptive hole and requires an adapter to connect to the pneumatic tubing. It would have been a better design if the diagnostic head had a male projection similar to the chromed steel 20200 diagnostic head.
Most diagnostic otoscope heads today are manufactured from a plastic cryolite polymer. Instead of a projecting flanged rod for the attachment of a rubber tube, there is a hole drilled into the barrel of the otoscope head. This modification requires a simple plastic male adapter to fit through the hole in the barrel and serve as an anchor for the tube leading from the rubber pneumatic bulb.
The cylindrical body made of chromed stainless steel is still available from several manufacturers (including the Welch-Allyn 20200), and it is preferred by most experts in pneumatic otoscopy. It is the recommended diagnostic otoscope head at Children’s Hospital of Pittsburgh and University of Pittsburgh School of Medicine.
Performing the procedure
The art of pneumatic otoscopy is difficult and often not well mastered, yet it is essential for accurate diagnosis of health or disease in the middle ear cleft.
A summary of five studies that compared the accuracy of pneumatic otoscopy with that of myringotomy for otitis media with effusion had a mean sensitivity score of 89% and mean specificity score of 80%. In one study of the frequency of use of the pneumatic otoscope, only 21% of respondents always used it and 42% never used it.
The pneumatic otoscope permits a small volume of generated negative followed by positive air pressure to assess the mobility of the tympanic membrane in an outward (laterally, toward the examiner), and inward direction. When the pressure in the middle ear cleft is the same as the pressure in the exam room, the normal TM moves about 1 mm laterally and 1 mm medially. Impedance to the medial movement of the TM usually means either there is a liquid (mucus, serum, blood or pus) in the middle ear cleft, a solid mass such as a tumor or cholesteatoma is occupying the middle ear cleft or the TM is retracted medially. Any of the above can impede its further medial movement of the TM when positive pressure is generated through the pneumatic otoscope.
We all recognize that acute otitis media and otitis media with effusion are among the most frequent upper respiratory diseases in infants, toddlers and preschool children. In my experience in northern Virginia, the technique of proper pneumatic otoscopy is not well demonstrated by teachers of physical diagnosis and is poorly understood by medical students, family practice and pediatric residents.
Prerequisites
There are several essential prerequisites that must be in place before the technique of pneumatic otoscopy can be successful. Every examination room should contain a halogen-illuminated otoscope with a charged nickel-cadmium battery that has not passed its expiration date, normally two years after purchase. As noted in a previous column “Maintenance of the office otoscope,” halogen bulbs that cost approximately $25 each should be replaced every four-to-six months after frequent use.
The child’s ear canals must be cleaned of almost all debris, including cerumen and desquamated skin, to permit visualization of the entire circumference of the TM. A common error is to peek through a small hole in the cerumen and diagnose middle ear pathology by visualization of a tiny part of the TM. The various techniques of cleaning out the ear canal also were addressed in a previous column.
Many pediatricians who are validated experts in pneumatic otoscopy use a stainless steel angulated #0 or #1, Buck’s design cerumen curette to remove ear canal debris in most children. There are no data that I am aware of that evaluate the effectiveness of twisted nasopharyngeal swabs or commercially available plastic cerumen loops or spoons compared with the standard stainless steel aural curette. Babies’ and toddlers’ heads can be immobilized in a lateral position (one ear facing toward the examiner), often against their mother’s chest.
Pneumatic otoscopy rules
Rule #1: Every pneumatic otoscope must be tested periodically for leaks in the intrinsic and extrinsic system. To examine for air leaks in the intrinsic system, the examiner need only to attach an aural speculum to the diagnostic otoscope head and occlude the end of the speculum with the tip of an index finger. Positive pressure is applied into the cylindrical body of the otoscope head by means of an attached rubber or plastic tube connected to a rubber bulb or inserted into the mouth of the examiner. If there is a seal-leak either at the junction between the open end of the cylindrical body of the otoscope and the aural speculum or at the junction between the retractable lens cap and the body of the otoscope, there will be a leak of pressurized air at the site of the faulty seal.
There are three sites where air leaks can occur in the extrinsic system, the most common of which is at the junction between the tip of the aural speculum and the child’s ear canal. The pressurized air then leaks out of the external auditory meatus. The TM appears to be immobile or poorly mobile, and the examiner erroneously believes that the child has otitis media with effusion.
For this reason, it is essential that a size 3 or 4 aural speculum be used for most young children to achieve a good seal which may or may not be airtight.
Adolescents and young adults often require a commercially-available 5 mm or 7 mm, SofSpec rubber tip aural speculum (Welch-Allyn). Should the 3 mm or 4 mm speculum persist in having an air leak after applying tragal pressure, the problem can be overcome by cutting off a 2 mm band from 3/8 inch diameter latex rubber tubing, and attaching this rubberband gasket over the tip of the aural speculum.
I recommend that the aural speculum (without the rubber gasket described above) be inserted at almost 1 cm into the ear canal of infants and young children, to achieve a good seal and to focus the light beam on the plane of the TM. Because some ear canals are not perfectly round and there is an imperfect seal between the speculum tip and the ear canal, it is often necessary to improve the air seal by pressing an index finger tip on the child’s tragus, which in turn improves the seal between the speculum tip and the ear canal wall.
Another site of possible air leak in the extrinsic system is at the junction between the male adapter connecting the rubber tube to the black resin body of the popular, yet not recommended by me, diagnostic otoscope. This type of air leak may be difficult to remedy and may require a larger size of the adapter, application of a flexible material around the inserting tip or re-machining of the hole in the otoscope head.
A third site of possible leak is a pinpoint perforation of the rubber tube that connects the body of the diagnostic otoscope with either a pneumatic bulb or a plastic mouthpiece. With age and deterioration of the rubber, pinpoint perforations can develop anywhere in the rubber tubing but particularly where one end of the tubing connects to the male adapter (or to the flanged part of the male adapter on the cylindrical body of the stainless steel diagnostic otoscope head).
It should be underscored that the TM itself must not have any perforations for successful pneumatic otoscopy. This includes small pinpoint perforations or patent tympanostomy tubes.
Rule #2: Straighten out the ear canal to get the most direct route for the otoscope speculum to be inserted to the optimal depth by gently pulling the superior helix of the auricle outward and downward in infants and upward and back in older children. This is a general rule that requires modification and individualization to get the straightest line possible to insert the otoscope speculum. The speculum should be inserted with a gentle rotating motion in infants and in children with Down syndrome because such children often have stenotic ear canals, causing much difficulty in visualization of the TM.
Rule #3: Application of gentle negative pressure against the TM to evaluate lateral (outward) motion of the TM is essential. Pneumatic otoscopy is not simply application of positive pressure applied by means of a pneumatic bulb or by puffs of air from the mouth of the examiner through the rubber tube into the airtight pneumatic otoscope head. The proper pneumo-otoscopic technique requires that the examiner first create a negative pressure through the rubber tube via bulb or mouth to transfer that negative pressure against the tympanic membrane. This is a critical part of pneumatic otoscopy and is infrequently taught or used by pediatric trainees, hospitalists or pediatricians in practice.
Why am I underscoring that the application of negative pressure is a requirement? When positive pressure is only applied against a TM that is simply retracted and there is a normal air-filled (under reduced air pressure, however) middle ear cleft, the TM will not move inward and the examiner may mistakenly diagnose otitis media with effusion (secretory otitis media). Should the TM appear dull and red and there is no movement with the application of positive pressure only through the pneumatic otoscope, the examiner may erroneously diagnose AOM and may injudiciously prescribe antibiotics.
Rule #4: Application of negative pressure followed by positive pressure must be gentle, and each must be repeated several times. A common error is to apply excessive amounts of compression to the pneumatic bulb. The bulb should be gently indented and not firmly squeezed.
Cavanaugh studied the amount of positive pressure delivered during pneumatic otoscopy in 53 pediatric patients. The pressures generated ranged from 338 mm to 1,134 mm of water. The mean pressure introduced was 748 mm water with the pneumatic bulb and 502 mm water through the mouthpiece method.
Some may find it easier to apply a similar gentle amount of negative or positive pressure by the admittedly unhygienic mouthpiece method than by the pneumatic bulb. The result of this application of overpressure is to cause a TM to move inward even when there is a significant amount of thin serous fluid in the middle ear.
When the pneumatic bulb is used, the examiner should gently compress the bulb slightly inward, then insert the aural speculum into the ear canal and re-seal the system using, if necessary, tragus compression externally against the ear canal opening. After an airtight seal is secured, the examiner releases the compression on the bulb, which causes the TM to move laterally toward the examiner’s eye. To repeat the application of negative pressure with the pneumatic bulb, it is necessary to remove the aural speculum and again apply gentle compression of the pneumatic bulb following which that aural speculum is reinserted into the ear canal and sealed airtight.
Rule #5: Validate your otoscopic skills frequently, using either spectral gradient acoustic reflectometry (Ear Check), tympanometry or both. Online courses on the technique of pneumatic otoscopy are sponsored by the AAP (Pedialink); Children’s Hospital of Pittsburgh (Enhancing Proficiency in Otitis Media) ePROM curriculum, at http://pedsed.pitt.edu and Diagnostic Ear Assessment Resource (DxEAR) at http://pdsweb.pdsedc.com/dxear (by invite only); Dr. Michael Pichichero (Outcome Management Educational Workshops. Workshop schedule on the internet at www.omew.com), and others. Although the color of the “normal TM” has a blue hue, the videos of actual pneumatic otoscopic technique is very well done.
If time permits, one morning, visit your otolaryngology colleague (preferably a pediatric ENT) and compare your pneumatic otoscopic diagnosis with that of the specialist.
One problem is that primary care pediatricians will encounter many more cases of acute otitis media than the specialist and children with AOM may not be seen the same day as you are in the office or operating room.
Rule #6: Exchange your black, rectangular-shaped diagnostic otoscope with the laterally sliding lens cap for the chromed stainless steel cylindrical model. Do not use the omnipresent disposable 2.5 mm black aural specula to examine the ears of infants and toddlers. They are of a particularly poor design to be inserted deep enough into the ear canals of babies, they often allow air leaks between the tip of the speculum and the infant’s ear canal, and the light beam is focused proximal to the surface of the TM instead of on the TM. Thus, the light is somewhat less concentrated on the TM itself. Stan Block, MD, published an excellent commentary in Pediatrics, where he succinctly noted several reasons to “dispose of the disposables.” If you are serious about improvement of pneumatic otoscopy skills, this rule should be followed.
Conclusion
There continues to be an uphill struggle to educate the educators and their students and primary care residents about pneumatic otoscopy and the preferred technique to develop expertise in this procedure. The most consistent and reproducible results occur when the instrument is powered by nickel cadmium or lithium batteries, halogen or halogen-xenon bulbs, an airtight system, a chromed stainless steel otoscope diagnostic head and the original nylon aural specula (cleaned with alcohol after each use) — certainly not the 2.5 mm disposable specula. It should be an integral part of the otoscopic examination of all young children.
For more information:
- Richard H. Schwartz, MD, is from the Department of Pediatrics at Inova Fairfax Hospital for Children, Falls Church, Va.
- Block SL. Acute otitis media: Bunnies, disposables and bacterial original sin. Pediatrics. 2003;111:217-218.
- Cavanaugh RM Jr. Obtaining a seal with otic specula: Must we rely on an air of uncertainty? Pediatrics. 1991;87:114-116.
- Cavanaugh RM Jr. Pneumatic otoscopy in infants and children. South Med J. 1982;75:335-338.
- Cavanaugh RM Jr. Pediatricians and the pneumatic otoscope: are we playing it by ear? Pediatrics. 1989;84:362-364.
- Jones WS, Kaleida PM. How helpful is pneumatic otoscopy in improving diagnostic accuracy? Pediatrics. 2003;112:510-13.
- Kaleida PH. The COMPLETES exam for otitis. Contemp Pediatr. 1997; 14:93-101.
- Pichichero ME. Acute otitis media: Part 1. Improving diagnostic accuracy. Am Fam Physician. 2000;61:2051-2056.
- Preston K. Pneumatic otoscopy: a review of the literature. Issues Compr Pediatric Nurs. 1998;21:117-128.
- Schwartz RH. New concepts in otitis media. Am Fam Physician. 1979;20:91-98.
- Schwartz, RH. The maintenance of the office otoscope. Infect Dis Child. 2001;14:8-9.
- Schwartz RH. Gleanings from a professional lifetime of cleaning out kids’ ear canals. Infect Dis Child. 2001;14:38,40.
- Schwartz RH. The pneumatic otoscope, a new instrument for examination of the tympanic membrane – E. Siegle 1864. Int J Pediatr Otorhinolaryngol. 1980; 2:261-263.
- Schwartz RH, Bahadori R. Examining the eardrum of infants with Down syndrome. Infect Dis in Children. 2002;15:8.
- Schwartz RH, Stool SE, Rodriguez WJ, Grundfast KM. Acute otitis media: Toward a more precise definition. Clin Pediatr (Phila). 1981;20:549-554.
- Shiao AS, Guo YC. A comparison assessment of videotelescopy for diagnosis of pediatric otitis media with effusion. Int J Pediatr Otorhinolaryngol. 2005;69:1497-1502.