Introduction
Otic barotrauma can be defined as a pathological change to the eardrum, resulting from a pressure difference between the middle-ear cavity and the surrounding environment. It usually results from poor eustachian tube function, but other factors, including the degree of mastoid pneumatisation, also increase the likelihood of middle-ear barotrauma.Reference Uzun, Adali, Tas, Koten, Karasalihoglu and Devren1 Common symptoms include pain and hearing loss.Reference Stangerup, Tjernström, Harcourt, Klokker and Stokholm2 In more severe cases, vertigo and discharge are reported.Reference Westerman, Fine and Gilbert3 Rarely, otic barotrauma results in long-term morbidity including tympanic membrane perforation,Reference Edmonds4 conductive and sensorineural hearing loss,Reference Gussen5 and perilymph fistula.Reference Love and Caruso6
Fortunately, various prevention measures exist, from simple manoeuvres such as yawning and swallowing, to performing a Valsalva manoeuvre. In addition, medical intervention has shown some limited benefit, with evidence that decongestants can reduce the ear discomfort associated with barotrauma in adults.Reference Csortan, Jones, Haan and Brown7
Flying is now an affordable luxury for a large proportion of the UK population and although modern aircrafts pressurise cabins to reduce otic barotrauma and other sequelae, it is still a problem with little public awareness. United Kingdom airports handled 221 million passenger flights in 2012,8 and around 50 per cent of adults in the UK were estimated to have flown in 2010.Reference Airport9 The prevalence of eustachian tube dysfunction in adults is estimated at 0.9 per cent;Reference Browning and Gatehouse10 in children, this is nearer to 30 per cent.Reference Fiellau-Nikolajsen11 In modern aircrafts, cabin air pressure at cruising altitude is lower than air pressure at sea level. At typical cruising altitudes (range: 11 000–12 200 m), cabin air pressure is equivalent to the outside air pressure at 1800–2400 m above sea level.12 The subsequent changes in pressure during ascent and particularly descent are often responsible for otic barotrauma. Physical signs of otic barotrauma in air travellers in one study were reported in 10 per cent of adults and 22 per cent of children.Reference Stangerup, Tjernström, Klokker, Harcourt and Stokholm13 As a result, it is an extremely common, yet preventable, morbidity associated with flying.
Primary literature about otic barotrauma has previously focused on the causes, prevention and treatment options available. There are few data to establish how common it is, and more importantly, no data assessing the public's awareness of otic barotrauma and its prevention. The fact that otic barotrauma is an easily preventable condition using simple measures highlights the importance of raising public awareness. In addition, public health strategies, including health education, are crucial to sustaining a healthy population against the background of an increasingly pressured National Health System (NHS). This study, therefore, used a survey to assess symptom frequency, and, in particular, awareness of prevention measures among UK air travellers. Following a literature review, we make suggestions on how to raise awareness.
Methods
After gaining approval from the National Research Ethics Service and the local Research and Development Committee, voluntary answers to a questionnaire (Appendix 1) were collected over a two-week period at Plymouth and Birmingham airports in the UK.
The questionnaire was designed following a consensus between one otolaryngology consultant and three registrars (specialist registrar or above). A pilot questionnaire was conducted initially on a small, representative group, and any ambiguous questions were adjusted accordingly.
Results
In all, 179 air travellers (66 females and 113 males) with a mean age of 28 years (range: 15–72 years) completed the questionnaire. The majority of air travellers flew once a year (Figure 1).
Frequency of flying of the study cohort in response to the question: How often do you fly?
The most commonly reported symptom was otalgia (63 per cent). Popping noises were reported in 58 per cent of air travellers. The remainder of symptoms were reported in a minority of people, with 16 per cent of people interviewed reporting no symptoms (Figure 2).
Symptoms reported by the study cohort while flying in response to the question: Which of the following symptoms have you ever suffered from while flying?
The vast majority of people had not had any previous ear surgery. Twelve people reported previous surgery, with five specifying myringotomy and grommet insertion. (Seven people did not complete the text box specifying the type of surgery.)
Fifty-three people (30 per cent) had not heard of any prevention measures. More people had heard of the Valsalva manoeuvre than other measures (35 per cent) (Figure 3). Importantly, of the people who had not heard of any prevention measures, 25 per cent (45/179) complained of at least one symptom.
Air travellers' awareness of prevention measures, as expressed by the study cohort in response to the question: Which of the following prevention measures have you heard of?
Following the questionnaire, 81 per cent of people said they would either definitely or probably use prevention measures in the future. Eighty-three per cent of people were not aware of any information available on how to prevent otic barotrauma, with the Internet being reported most commonly as a source of information in only 10 per cent. Eighty-six per cent of people felt the provision of more information would be useful (Figure 4).
Post-questionnaire opinions of the air travellers surveyed in the study.
Discussion
Otic barotrauma is a common and preventable condition. The majority of people in our survey suffered from symptoms attributable to otic barotrauma when flying (84 per cent). Thirty per cent of passengers interviewed had never heard of any prevention measures. Interestingly, 25 per cent of those with no awareness of preventive measures complained of symptoms related to otic barotrauma. This suggests that 7.5 per cent of people in our survey were suffering from otic barotrauma and yet were unaware of any way of avoiding it. With 50 per cent of the UK population flying, this figure translates to significant, yet avoidable, morbidity. What is then needed is appropriate health education or an awareness campaign.
Unfortunately, a survey gives only the subjective symptoms associated with otic barotrauma rather than objective physical findings. For example, the perforation rate and the level or type of hearing loss cannot be quantified. Six per cent of people complained of discharge during flying, which suggests possible perforation of the tympanic membrane with subsequent discharge of a middle-ear effusion. There is no consensus on the incidence of perforation rates in air travellers, but previous reports indicate it is extremely rare.Reference Basu14 Our findings suggest this rate may be higher, although clearly it is difficult to know what proportion of air travellers complaining of discharge had a perforation or whether it was due to other causes, e.g. otitis externa. Fortunately, evidence from the military aviation literature suggests that most tympanic membrane perforations secondary to barotrauma heal spontaneously.Reference O'Reilly, Ernsting, Nicholson and Rainford15
Pressure differences between the middle and external ear are noticed with a pressure difference of only 8.7 kPa. If this pressure difference increases, mucosal congestion and oedema will occur in the middle ear. At pressure differences as low as 13 kPa, locking of the eustachian tube can occur after which movement of the levator veli palatine muscle will be unable to overcome the pressure differential, resulting in barotrauma.Reference Farmer, Bennett and Elliott16, Reference Keller17 Cabin pressures at cruise altitude are maintained at 1800–2400 m above sea level, which is a pressure difference of between 20 and 25 kPa less than the pressure at sea level. Therefore, failure to equalise can very easily result in barotrauma, and passengers who, for example, fall asleep are at particular risk of developing problems. In addition, the speed of descent appears to be an important factor. Aircrafts such as the Boeing 737 which descend more rapidly can therefore exacerbate otic barotrauma.Reference Kortschot and Oosterveld18
Many prevention measures are available, with variable efficacy. Two randomised controlled trials (RCTs) have compared oral pseudoephedrine against placebo in adults. Oral pseudoephedrine resulted in a significant reduction over placebo.Reference Edmonds4, Reference Jones, Sheffield, White and Bloom19 A Danish study found that performing the Valsalva manoeuvre could equalise middle-ear pressure in 46 per cent of air travellers; of those who could not equalise with the Valsalva manoeuvre, 69 per cent could clear the middle-ear pressure with a nasal balloon.Reference Stangerup, Tjernström, Klokker, Harcourt and Stokholm13 Nasal balloon devices, such as Otovent, are now readily available to the public at low cost. In children, a small RCT found that oral pseudoephedrine was no more effective at reducing ear pain at take-off or landing than placebo.Reference Buchanan, Hoagland and Fischer20 Similar to adults, however, auto-inflation using Otovent in one study of 45 children showed that 33 per cent could successfully equalise middle-ear pressure when using Otovent, against only 6 per cent of children performing a Valsalva manoeuvre.Reference Stangerup, Tjernström, Harcourt, Klokker and Stokholm2
To our knowledge, there are no studies comparing the effects of chewing gum/sucking sweets or yawning/swallowing; however, studies assessing eustachian tube function with video endoscopy or sonotubometry suggest these manoeuvres are effective in opening the eustachian tube and therefore allowing equalisation.Reference Handzel, Poe and Marchbanks21, Reference Poe, Pyykkö, Valtonen and Silvola22 One study of infants demonstrated that 78 per cent of non-bottle-fed infants cried during flight descent in comparison with 29 per cent of bottle-fed infants.Reference Byers23 Although clearly there are potential confounding variables, the findings suggest that swallowing is a useful mechanism to avoid otic barotrauma associated with descent.
• Otic barotrauma is common among air travellers due to pressure differences between the middle ear and the environment, particularly during flight descent
• It can cause significant morbidity, including otalgia, perforation of the tympanic membrane and conductive or sensorineural hearing loss
• Prevention measures are simple with varying evidence for their effectiveness
• In our survey, 30 per cent of air travellers were not aware of prevention measures. Twenty-five per cent of those who were not aware of prevention measures complained of barotrauma-related symptoms
• Targeted health education is needed to reduce morbidity
The measures described in this article are all straightforward options, requiring no prescription or training. Increasing pressures on the NHS, as pointed out in the Wanless report in 2004,Reference Wanless24 have highlighted the need to promote prevention as well as cure. Health education is an established, effective means of implementing this, with leaflets, websites, radio advertisements and personal communication all being effective.Reference Waddell, O'Connor, Boorman and Torsney25, Reference McAvoy and Raza26 Although no English-language literature exists with regards to otic barotrauma during air travel, one RCT assessed the effectiveness of health education leaflets in reducing the incidence of sunburn among air travellers. In the intervention arm, leaflets were placed in seat pockets on outgoing and return flights, and both control and intervention arms were distributed questionnaires. Interestingly, the leaflet did not reduce the incidence of severe sunburn.Reference Dey, Collins, Will and Woodman27 The authors admitted that they did not ask passengers whether they had read or just ignored the leaflet, or if the messages were inappropriate. However, the availability of in-flight leaflets during the onset of symptoms from otic barotrauma should improve compliance with prevention measures.
After completing our survey, 81 per cent of people said they would ‘definitely’ or ‘probably’ use prevention measures in the future, which suggests that people assimilate the information very quickly. The majority (83 per cent) of people were not aware of any information being available, and 86 per cent said more information would be useful, both highlighting the importance of making this information available.
Prevention of otic barotrauma is straightforward. Medical treatments are available from chemists within airports, and non-medical treatments require little or no training. For this reason, it would make sense to make information available in airports and in flight as part of a health education campaign. To date, this is the only survey assessing air travellers' awareness of otic barotrauma and its prevention strategies. It clearly highlights the need for public education.
Conclusion
Air travellers are not aware of prevention measures to avoid otic barotrauma, even though the majority suffer from it. There are long-term sequelae, which in some cases will cause enough morbidity to warrant specialist opinion. Prevention is simple and its implementation could be carried out with public health education.
Appendix 1. Questionnaire used to sample the air travellers in our survey
1. What is your age?
2. What is your sex?
3. What is your occupation? (optional)
4. How often do you fly?
□ Up to 12 times per year
□ Up to six times per year
□ Up to three times per year
□ Up to once a year
□ Less than every other year
5. Which of the following symptoms have you ever suffered from while flying?
□ Ear pain
□ Popping noises
□ Ear discharge
□ Reduced hearing
□ Dizziness
□ Ringing noises in the ear
□ None of the above
6. Have you had previous ear surgery?
□ Yes
□ No
If yes, please specify what type:
7. Which of the following prevention measures have you heard of?
□ Yawning/swallowing
□ Chewing gum/sweets
□ Otovent
□ Decongestants (e.g. Sudafed)
□ Blowing against a pinched nose (Valsalva manoeuvre)
□ None of the above
8. Would you consider using these measures now?
□ Definitely yes
□ Probably yes
□ Maybe
□ Probably no
□ Definitely no
9. Are you aware of any information available to air travellers? If so, please specify from the options below or select Other.
□ Leaflets/posters at airports
□ Leaflets/posters in aeroplanes
□ Leaflets/posters in GP practices/hospital
□ Internet
□ Other
□ None of the above
If Other, please specify
10. Do you think provision of more information would be useful?
□ Yes
□ Unsure
□ No
