ONeill
Linear compression to 2.4 ATA over 15 minutes reduced eustachian tube dysfunction and middle ear barotrauma compared to compression over 10 minutes.
Clinical bottom line
- Increasing the time from 10 to 15 minutes for linear compression to 2.4 ATA (14 msw) linear compression resulted in fewer incidences of symptomatic ETD and MEB. That regimen was also better than 10 or 15 minute non-linear compressions.
- No difference in incidences of symptomatic ETD and MEB between linear and non-linear dives.
Citation:O’Neill OJ, Dayya D, Varughese L, Marker JA, Perez L, Dayya M. The effect of total compression time and rate (slope) of compression on the incidence of symptomatic Eustachian tube dysfunction and middle ear barotrauma: a Phase II prospective study. Undersea and Hyperbaric Medical Society. 2021, 4(3):344-345.
Lead author’s name and email:OJO’Neill: OONeill@Northwell.edu
Three-part clinical question:In patients having HBOT, does varying the total compression time and rate of compression, compared to a standard linear compression over 10 minutes, result in reduced incidence and severity of symptomatic middle ear barotrauma?
Search terms:Eustachian tube, barotrauma, compression
The study:Non-blinded randomised crossover trial with intention-to-treat.
The study patients:Patients having HBOT at 2.4 ATA in a multiplace chamber.
Control group:(N = 309, 309 runs analysed): 10-min linear compression to 2.4 ATA.
Experimental group:(N = 312; 312 runs analysed): 15-min linear compression to 2.4 ATA.
The evidence
Outcome |
Time to Outcome |
10 m linear group |
15 m linear group |
Relative Risk Reduction |
Absolute Risk Reduction |
NNT |
No. of compression stops |
End compression |
0.25 |
0.12 |
52% |
0.10 |
10 |
95% CI: |
28% to 76% |
0.07 to 0.19 |
5 to 14 | |||
Middle ear barotrauma Grade 1 + 2 |
End compression |
0.416 |
0.324 |
22% |
0.092 |
11 |
95% CI: |
-23% to 67% |
-0.1 to 0.28 |
NNT = 4 to INF; NNH = 11 to INF |
Comments
- The unit of analysis was treatment run rather than individual outcomes.
- Authors compared 10 and 15 minutes for both a linear and an accelerating rate of compression. In general non-linear compression produced more problems. We have chosen to give the linear comparisons here.
- Almost half of symptomatic barotrauma incidents were not graded due to equipment failure during the study.
- The mean depth of stops was 4.9±2.6 msw. Probably typical clinical experience.
- Some evidence that stops were more likely early in patient treatment course.
- The authors developed the O’Neill Grading System to categorise the clinical severity of MEB (0 symptoms only to 3 most severe).
Appraised by:Bosco Tran bosco.tran@student.unsw.edu.au
Kill or update by: February 2026