Abstract
Introduction
Changes in air pressure during flying can cause ear-drum pain and perforation, vertigo, and hearing loss. It has been estimated that 10% of adults and 22% of children might have damage to the ear drum after a flight, although perforation is rare. Symptoms usually resolve spontaneously.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of interventions to prevent middle-ear pain during air travel? We searched: Medline, Embase, The Cochrane Library and other important databases up to April 2007 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
Results
We found four systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
Conclusions
In this systematic review we present information relating to the effectiveness and safety of the following interventions: nasal balloon inflation; oral pseudoephedrine; and topical nasal decongestants.
Key Points
Changes in air pressure during flying can cause ear-drum pain and perforation, vertigo, and hearing loss. Barotitis is inflammation of the ear drum as a consequence of air pressure changes.
It has been estimated that 10% of adults and 22% of children might have damage to the ear drum after a flight, although perforation is rare.
Symptoms usually resolve spontaneously.
Nasal balloon inflation may reduce symptoms of barotitis in people during air travel.
Oral pseudoephedrine may reduce symptoms in adults with previous ear pain during flights.
We don't know whether oral pseudoephedrine is also beneficial in children, but it can cause drowsiness.
We don't know whether topical nasal decongestants can prevent symptoms of barotrauma.
About this condition
Definition
The effects of air travel on the middle ear, as a result of changes in air pressure, can include ear-drum pain, vertigo, hearing loss, and ear-drum perforation.
Incidence/ Prevalence
The prevalence of symptoms depends on the altitude, type of aircraft, and characteristics of the passengers. One point prevalence study found that, in commercial passengers, 20% of adult and 40% of child passengers had negative pressure in the middle ear after flight, and that 10% of adults and 22% of children had otoscopic evidence of damage to the ear drum. We found no data on the incidence of perforation, which seems to be extremely rare in commercial passengers.
Aetiology/ Risk factors
During aircraft descent, the pressure in the middle ear drops relative to that in the ear canal. A narrow, inflamed, or poorly functioning Eustachian tube impedes the necessary influx of air. As the pressure difference between the middle and outer ear increases, the ear drum is pulled inwards.
Prognosis
In most people, symptoms resolve spontaneously. Experience in military aviation shows that most ear-drum perforations will heal spontaneously.
Aims of intervention
To prevent ear pain and trauma during air travel.
Outcomes
Barotrauma (includes incidence and severity of pain and hearing loss, and incidence of perforation of ear drum).
Methods
Clinical Evidence search and appraisal April 2007. The following databases were used to identify studies for this systematic review: Medline 1966 to April 2007, Embase 1980 to April 2007, and The Cochrane Database of Systematic Reviews and Cochrane Central Register of Controlled Clinical Trials 2007, Issue 1. Additional searches were carried out using these websites: NHS Centre for Reviews and Dissemination (CRD) — for Database of Abstracts of Reviews of Effects (DARE) and Health Technology Assessment (HTA), Turning Research into Practice (TRIP), and NICE. We also searched for retractions of studies included in the review. Abstracts of the studies retrieved from the initial search were assessed by an information specialist. Selected studies were then sent to the author for additional assessment, using pre-determined criteria to identify relevant studies. Study design criteria for inclusion in this review were: published systematic reviews and RCTs in any language, at least single blinded, and containing more than 20 individuals of whom more than 80% were followed up (those studies with less than 80% follow-up but with intention-to-treat analysis were considered). There was no minimum length of follow-up required to include studies. We excluded all studies described as “open”, “open label”, or not blinded unless blinding was impossible. In addition, we use a regular surveillance protocol to capture harms alerts from organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA), which are added to the reviews as required. To aid readability of the numerical data in our reviews, we round many percentages to the nearest whole number. Readers should be aware of this when relating percentages to summary statistics such as relative risks (RRs) and odds ratios (ORs). We have performed a GRADE evaluation of the quality of evidence for interventions included in this review (see table). The categorisation of the quality of the evidence (high, moderate, low, or very low) reflects the quality of evidence available for our chosen outcomes in our defined populations of interest. These categorisations are not necessarily a reflection of the overall methodological quality of any individual study, because the Clinical Evidence population and outcome of choice may represent only a small subset of the total outcomes reported, and population included, in any individual trial. For further details of how we perform the GRADE evaluation and the scoring system we use, please see our website (www.clinicalevidence.com).
Table.
GRADE Evaluation of interventions for Middle-ear pain and trauma during air travel.
| Important outcomes | Barotrauma | ||||||||
| Studies (Participants) | Outcome | Comparison | Type of evidence | Quality | Consistency | Directness | Effect size | GRADE | Comment |
| Preventing middle-ear pain during air travel | |||||||||
| 1 (120) | Barotrauma | Nasal balloon inflation versus control | 4 | –2 | 0 | –1 | 0 | Very low | Quality points deducted for sparse data and inclusion of controlled clinical trial. Directness point deducted for differences in flights taken between intervention and control |
| 2 (272) | Barotrauma | Oral pseudoephedrine versus placebo | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for uncertainty about assessment of outcome |
| 1 (91) | Barotrauma | Pseudoephedrine (oral) in children versus placebo | 4 | –2 | 0 | 0 | 0 | Low | Quality points deducted for sparse data and for analysis of a different measure than that randomised (children randomised but analysis based on number of flights) |
| 1 (83) | Barotrauma | Topical decongestants versus placebo | 4 | –1 | 0 | 0 | 0 | Moderate | Quality point deducted for sparse data |
We initially allocate 4 points to evidence from RCTs, and 2 points to evidence from observational studies. To attain the final GRADE score for a given comparison, points are deducted or added from this initial score based on preset criteria relating to the categories of quality, directness, consistency, and effect size. Quality: based on issues affecting methodological rigour (e.g., incomplete reporting of results, quasi-randomisation, sparse data [<200 people in the analysis]). Consistency: based on similarity of results across studies. Directness: based on generalisability of population or outcomes. Effect size: based on magnitude of effect as measured by statistics such as relative risk, odds ratio, or hazard ratio.
Glossary
- Barotrauma
Symptoms caused by changes of atmospheric pressure are called barotrauma. In the ear, these include ear drum pain, vertigo, hearing loss, tinnitus, and ear drum perforation.
- Low-quality evidence
Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
- Moderate-quality evidence
Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
- Very low-quality evidence
Any estimate of effect is very uncertain.
Disclaimer
The information contained in this publication is intended for medical professionals. Categories presented in Clinical Evidence indicate a judgement about the strength of the evidence available to our contributors prior to publication and the relevant importance of benefit and harms. We rely on our contributors to confirm the accuracy of the information presented and to adhere to describe accepted practices. Readers should be aware that professionals in the field may have different opinions. Because of this and regular advances in medical research we strongly recommend that readers' independently verify specified treatments and drugs including manufacturers' guidance. Also, the categories do not indicate whether a particular treatment is generally appropriate or whether it is suitable for a particular individual. Ultimately it is the readers' responsibility to make their own professional judgements, so to appropriately advise and treat their patients.To the fullest extent permitted by law, BMJ Publishing Group Limited and its editors are not responsible for any losses, injury or damage caused to any person or property (including under contract, by negligence, products liability or otherwise) whether they be direct or indirect, special, incidental or consequential, resulting from the application of the information in this publication.
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