Portuguese Version

Year:  2004  Vol. 70   Ed. 1 - (16º)

Artigo Original

Pages: 102 to 105

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Barotitis media in crewmembers of commercial airlines

Author(s): Adriana Geórgia Davim Bastos 1,
Alexandra Torres Cordeiro Lopes de Souza 2

Keywords: barotitis, barotrauma, tubal function

Abstract:
Barotitis media (BM) is defined, by Armstrong & Hein, as a chronic or acute traumatic inflammation caused by variations of atmospheric pressure. Aim: The purpose of the present study was to analyze clinical aspects related to BM in crewmembers of commercial airlines. Study Design: Clinical retrospective. Material and Method: A group of 17 patients with BM was evaluated from December 2002 to September 2003. Aspects related to age, gender, clinical history, treatment and follow-up were studied. Results: Of the 17 patients, 11 were males and 6 females, aged from 28 to 51, with average of 37,3 years old. All of them complained of ear pain during the descent phase of the flight prior to land. 14 patients (82,4%) complained of aural pressure and two of tinnitus. Before the flight, 11 patients (64,7%) had complains related to upper respiratory tract. Barotrauma was observed grade 1 in 17,6% of patients, grade 2 in 58,8% and grade 3 in 23,6%. Nobody had barotrauma grade 4. The patients were treated with oral decongestants associated or not with antibiotics and corticosteroids. Conclusion: BM is a peculiar disease in aerospace medicine and otorhinolaringology areas. Understanding of pathogenesis and prevention mechanisms of BM is essential for the management of these patients.

INTRODUCTION

Middle ear barotrauma or barotitis media (BM) was defined by Armstrong & Hein as acute or chronic traumatic inflammation caused by atmospheric pressure affections 1.

The most common cause of BM is atmospheric pressure changes during commercial flight landing, associated with the passengers' inability to balance the middle ear pressure with atmospheric pressure. During landing, the difference in pressure between the middle ear and environmental pressure should be equalized to prevent barotrauma. To some, this balance can be easily reached by swallowing, moving the mandible or yawning. To others, it is necessary to conduct Valsalva maneuvers a number of times during landing and, even so, some passengers do not reach balance 7.

In two thirds of the cases, crewmembers' disease are owing to upper airway infections. The infections are facilitated by work conditions: dry air, atmospheric pressure fluctuation, air current through open doors in the airports, passengers infections and climatic changes. Owing to the risk of developing barotrauma, crewmembers are instructed not to fly when they have upper airway breathing symptoms 4.

The purpose of the present study was to analyze the clinical aspects related to middle ear barotrauma in commercial airline crewmembers.

MATERIAL AND METHOD

We retrospectively studied 17 cases of BM in the period between December 2002 and September 2003 among commercial airline crewmembers seen in the Ambulatory of Otorhinolaryngology, medical service of Fundação Ruben Berta (FRB), Rio de Janeiro-RJ.

The review of the medical charts collected and analyzed data concerning gender, age, clinical picture, evolution and treatment.

RESULTS

In the period of 10 months we diagnosed 17 cases of BM, being 11 men and 6 women, mean age of 37.3 years, ranging from 28 to 51 years.

On average, patients were seen in the period of 1 to 3 days after the flight. They all presented otalgia during landing, being unilateral in 9 cases (53%) and bilateral in 8 cases (47%). Fourteen cases (82.4%) presented complaint of ear fullness, being the symptom that took longer to resolve with treatment, ranging from 5 to 10 days. Tinnitus was detected in 2 cases. During the flight, 11 patients (64.7%) presented a picture suggestive of associated upper airway infection and in one patients there was also allergic rhinitis.

Otomicroscopy classified patients according to the findings described in Teed's classification for middle ear barotrauma (see Tables 1 and 2).

Symptom regression was complete in all cases, with mean of 5 to 10 days in 82.4% of the cases and over 10 days in the others. On average, patients were 5 to 10 days away from their activities. After reversion of ear fullness, no patients complained of hearing loss.

Treatment was conservative in all cases and the preferred approach was the use of antibiotics, corticoids and decongestant (loratadine/ pseudoephredine or phexofenadine/pseudoephredine), by oral administration. In 9 cases (53%) we prescribed the association of three drugs, being that all of them had a suggestive picture of upper airway infections. In three patients (17.6%) we used a combination of antibiotics and decongestants and in the other 5 cases, only decongestants.

DISCUSSION

Barotitis is caused by the maintenance of negative pressure in the middle ear (ME) during and after airplane landings. The increase in ME negative pressure is the result of the increase in pressure in the cockpit during landing and the passengers' inability to balance the middle ear pressure with atmospheric pressure 7.

In pressurized airplanes, the difference between the atmospheric pressure and ME pressure is very marked, which facilitates the equalization of pressure between both of them. However, since it is not completely cancelled, BM can also occur, especially in cases of preexisting auditory tube obstruction. The difference in pressure between the environment and ME is essential for the development of BM, but it is more important to know how fast it can start. Quick variation is much more deleterious than wide variation 2.

Boyle's law says that volume of a dry gas at constant temperature varies inversely with the pressure around it. This law is applied to closed cavities. Even though the gas contained in the paranasal cavities and ME are humidified, this law provides a base to help us understand the pathophysiology of barotrauma in aviation 2, 8.

ME is ventilated through the auditory tube that has around 34mm. Its external 1/3 is bony and the internal 2/3, towards the nasopharynx, is cartilaginous. The lumen is narrower in the bone and cartilaginous joining segment. At rest, the auditory tube is closed by the passive effect of the spring of its cartilaginous portion. It opens intermittently with swallowing, yawning, and mandibular movements through the action of three muscles: palatine veli tensor, palatine veli elevator and salpingopharyngeus 2, 8. The auditory tube main function is to ventilate the ME, protecting the ME from nasopharynx contamination and clean secretions of ME towards the nasopharynx 10.

Auditory tube physiology is affected during a flight. When the plane takes off, atmospheric pressure reduces and at the same time there is an increase in relative pressure in the ME, which takes to a sensation of ear fullness and bulging of the TM. The ME pressure continues to increase up to an approximate gradient of 15mmHg, when the tube is forced to open, the air leaks and the gradient is relieved. Normally, this mechanism occurs with some facility, since the tube is a good ME conductor to the nasopharynx. This mechanism is repeated until the desired altitude is reached 8, 10.

The inverted situation happens during landing, when relative negative pressure is developed into the ME. This pressure difference does not normally resolve spontaneously owing to the valve mechanism that acts in the cartilaginous portion of the tube when air is forced from the nasopharynx into the ME. Thus, the auditory tube tends to remain closed. Many passengers tend to compensate this block by making pressure in the TM by chewing gun, frequently swallowing, yawning, or through Valsalva maneuver. When the ME is not ventilated during airplane landing, partial vacuum is created, the pressure gradient between the nasopharynx and ME can exceed 90mmHg, and then the palate muscle is not strong enough to open the tube, which is blocked. As a consequence, we can have barotitis 8.

Hanna, in 1989, analyzed 101,706 training flights in simulators of the American Air Force and confirmed that there were 27% of barotrauma cases, being 64% of barotitis. Studies about barotraumas are scarce and in Brazil there are no statistical studies about the topic 3.

ME affections are characterized specially by acute inflammatory process of the mucosa, especially present during negative pressure, which by suction can cause edema, transudate, ecchymosis, and bleeding, forming hemotympanum. When the pressure in the ME exceeds 120mmHg, it can cause TM perforation 2.

The diagnosis of BM is clinical. Symptoms and physical findings of barotitis depend on severity of the case. In mild cases, patients complain of landing discomfort, but in aggravated cases patients may present severe pain, ear fullness, tinnitus, vertigo with nausea and deafness 8. In some cases, there may be displacement of ossicle chain, pressing the stapes against the oval window, causing alterobaric dizziness 2. The physical examination can demonstrate retracted TM with or without hemorrhage, serous otitis media, hemotympanum or even TM perforation 8. The history of flights in the past days before the medical visit and presence of classical symptoms in most of the cases facilitate the diagnosis of patients.

Otoscopy data are classified into grades according to Teed's classification (1944) (see Table 1). Twelve of them flew under unfavorable conditions, being that 82.4% of the patients presented BM grades 2 or 3 of Teed, being that in no case there was TM perforation 9.

Any event that interferes in the appropriate ventilation of ME can predispose to barotrauma. Upper airways infections and allergic rhinitis are the most common causes. These conditions are associated with edema of the mucosa on the lumen of the auditory tube, edema, or lymphoid hyperplasia around the tube orifice and abnormalities that narrow the lumen, leading to the valve mechanism 8. Civil aviation crewmembers are instructed not to fly when they have upper respiratory disorders owing to the high risk of barotrauma. Fundaçao Ruben Berta/RJ has specialists in aerospace medicine and otorhinolaryngologists that assess crewmembers before the flights, upon request, in order to prevent cases of BM and its sequels. Another important aspect is the duration of medical leave, which in our study was 5 to 10 days on average.

Less common causes of BM are: tumors, polyps, septal deviation, auditory tube stenosis, and anatomical abnormalities that prevent normal ventilation of ME 8.

Differential diagnosis should be made with common causes of otalgia, such as acute otitis media (AOM) and external otitis. Less common causes include acute acoustic trauma, Bell's palsy, Herpes Zoster Oticus, toothache and middle ear and facial nerve tumors5 . All patients presented history of otalgia during the flight. Supported by other symptoms and the result of otomicroscopy it is possible to easily have the differential diagnosis.

The key points for differential diagnosis are: 1) recent history of plane trip with pain during landing is present in barotrauma but absent in AOM; 2) fever and leukocytosis are frequently presented in infectious pictures and absent in barotrauma; 3) purulent nasal discharge suggests upper airway infections and can trigger barotrauma; 4) TM retraction with serous-sanguinolent exsudate is present in barotitis, whereas TM bulging with mucopurulent exsudate is detected in AOM 8. Even though AOM and upper airway infections are different diagnoses, they are also adjuvant factors for the development of BM. In 14 cases (70.6%) there were upper airways obstructive symptoms (disorders and rhinitis) that facilitated BM.

According to Caldas & Duprat (2003), treatment of BM is essentially preventive 2. Prevention of most of the causes of barotrauma is simple, such as those associated with upper airway infections and allergic rhinitis. Subjects who are going to fly and manifest these conditions should take decongestant before the flight and use nasal drops or spray during the flight to reduce edema of mucosa that frequently triggers barotrauma. To babies, we should offer maternal milk or a bottle during landing and for older children, abundant liquid. Swallowing maneuvers, yawning, chewing gum and Valsalva maneuver should always be tried. The use of Otovent can produce good results. The use of local heat in the form of steam is questionable. We should be careful when prescribing anti-histamic drugs to pilots during the flight to avoid drowsiness 2, 6-8.

Valsalva's maneuver can prevent barotrauma during landing if the patient feels discomfort. The plane, if possible, should land slowly in order to try to have equalized pressures 8. Moser and Wolf, in 1990, assessed 69 patients with recurrent sinusitis and difficulty to equalize pressure during the flight, observing that in otological evaluation 57% of them had at least one of the auditory tubes blocked, as seen in tympanometry, 66% in Politzer test and 81% in Valsalva's maneuver. To the authors, these data are in accordance with the experience in testing applicants to pilot, in which they observed that Valsalva's maneuver followed by otoscopy was the most effective method to test auditory tube function.4

Risk factors (Schwartz, 1989) for BM when the auditory tube is poorly functioning are: 1) past history of otalgia during plane landing; 2) presence of nasal congestion with rhinorrhea; 3) repetitive landing in long flights; 4) absence of cockpit pressurization 6.

A rare but severe complication is development of perilymphatic fistula caused by rupture of round and oval windows secondary to barotitis 6. No patient presented complaint of dizziness during or after the flight. We did not perform auditory tests in our subjects, but all of them did not report hearing complaints after recovery. The two patients with tinnitus were submitted to audiometry after symptom regression, and the results were within the normal range in both cases.

Conservative treatment is recommended for BM with local and/or systemic decongestants. Corticoids are less used. General resolution occurs within a period of 10 days. During this period, flights should be avoided. Antibiotics are not necessary, unless it is apparently upper airway infection. Myringotomy is normally not justifiable, owing to the excellent results with conservative treatment 5, 8. We decided to associate antibiotics and/or corticoids in 11 patients (70.6%) that presented compatible symptoms of upper airway infections, since days after the flight, during the visit, they already manifested purulent nasal discharge and significant nasal congestion. Moreover, it is known that these patients need to recover quickly to resume their air activities.

CONCLUSION

Barotitis media is a peculiar disease in aerospace medicine and otorhinolaryngology. The understanding of pathophysiology and barotrauma prevention mechanisms of the middle ear is essential for the appropriate management of these patients.

Table 1. Classification of Teed to middle ear barotrauma9



Table 2. Classification of 17 cases concerning grade of BM, according to Teed's classification.

REFERENCES

1. Armstrong HG & Heim JW. The effect of flight on the middle ear. JAMA 1937; 109: 417-21.
2. Caldas N & Duprat A. Tratado de Otorrinolaringologia. 1a e d. São Paulo: Rocca; 2003. p.126-30.
3. Hanna HH. Aviation aspects of otolaryngology. In: Otolaryngology. Philadelphia: English GM ed.; 1986 p. 1-17.
4. Moser M & Wolf G. Recurrent sinusitis and impairment of obstruction tube function in air passengers and crew. Aviat space environ obs 1990; 61: 662-5.
5. O'Brien DM. Case#65. Aviat space environ med 1996; 67(8): 787-9.
6. Schwartz RH. Hazards of air travel for child with otitis. Pediatr infect dis J 1989; 8(8): 542-3.
7. Stangerup SE, Tjernstrom O, Harcourt J, Klokker M, Stokholm J. Barotitis in children after aviation: prevalence and treatment with Otovent. J laryngol otol 1996; 110: 625-8.
8. Stewart TW. Common otolaryngologic problems of flying. AFP 1979; 19(2): 113-9.
9. Teed RW. Factors producing obstruction of the auditory tube in submarine personnel. US naval medical bulletin 1944; 42: 293-306.
10. Weiss MH & Frost JO. May children with otitis media with effusion safely fly? Clin pediatr 1987; 26(11): 567-8.

1 Otorhinolaryngologist, post-graduated, Department of Surgery, focus on Otorhinolaryngology. Medical School, Federal University of Rio de Janeiro (UFRJ).
2 Otorhinolaryngologist, Master in Otorhinolaryngology, Medical School, UFRJ.
Affiliation: Serviço médico da Fundação Ruben Berta. Rio de Janeiro-RJ.
Address correspondence to: Adriana Geórgia Davim Bastos Rua Cambaúba, 354/101 Jardim Guanabara Ilha do Governador Rio de Janeiro RJ 21940-001.
Tel (55 21) 2463 1641/ 9975 0724 Fax (55 21) 2430-9120 E-mail: adrianageorgiabastos@bol.com.br
Study presented at III Congresso Triológico de Otorrinolaringologia, October 8 - 11, 2003, Rio de Janeiro-RJ.

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