Difference between revisions of "Mutzbauer"
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− | <span style=" | + | <span style="line-height:normal">'''<span style="font-size:18.0pt"><span style="font-family:" times="" new="" roman",serif"="">Administration of free-radical scavengers (vitamins C and E) before oxygen diving did not improve eustachian tube ventilatory function.</span></span>'''</span> |
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− | + | <span style="line-height:normal">'''<span style="font-size:14.0pt"><span style="font-family:" times="" new="" roman",serif"="">Clinical Bottom Line:</span></span>'''</span> | |
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− | + | <span style="line-height:normal"><span style="font-size:14.0pt"><span style="font-family:" times="" new="" roman",serif"="">1. Administration of vitamins C and E promoted rather than prevented negative ear pressures after oxygen diving.</span></span></span> | |
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− | + | <span style="line-height:normal"><span style="font-size:14.0pt"><span style="font-family:" times="" new="" roman",serif"="">2. The magnitude of the negative middle ear pressure was less after the second dive in both groups.</span></span></span> | |
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Citation/s:</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">1. Mutzbauer T, Mueller P, Tetzlaff K et al. Is eustachian tube ventilatory function (ETVF) impairment after oxygen diving mediated by free radicals? Undersea and Hyperbaric Medicine 2000; 27(suppl):16.</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Clinical Scenario:</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">A diver exposed to hyperbaric oxygen displayed negative middle ear pressures.</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Three-part Question:</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">In divers using high inspired oxygen, does the administration of vitamins C and E, compared to placebo, prevent negative middle ear pressure after diving?</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Search Terms:</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Middle ear, eustachian tube</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">The Study:</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Double-blinded concealed randomised controlled trial with intention-to-treat. Fit volunteer naval divers</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Control group (N = 8; 8 analysed):</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Placebo medication at least three hours before diving (oxygen rebreather at 4m for 30 minutes average) on two consecutive days.'''</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Experimental group (N = 7; 7 analysed):</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">1g vitamin C and 600 IU of vitamin E at least three hours prior to diving (same exposure).</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">The Evidence:</span></span>'''</span> | ||
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+ | {| class="Table" style="border:solid windowtext 1.0pt" | ||
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− | | <span style | + | | style="width:146.35pt; border:solid windowtext 1.0pt" width="198" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Non-event outcomes</span></span>'''</span></p> |
+ | | style="width:69.4pt; border:solid windowtext 1.0pt" width="95" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Time to outcome</span></span>'''</span></p> | ||
+ | | style="width:69.35pt; border:solid windowtext 1.0pt" width="94" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Placebo group</span></span>'''</span></p> | ||
+ | | style="width:69.4pt; border:solid windowtext 1.0pt" width="95" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Vitamin group</span></span>'''</span></p> | ||
+ | | style="width:87.3pt; border:solid windowtext 1.0pt" width="119" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">P-value</span></span>'''</span></p> | ||
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− | | <span style | + | | style="width:146.35pt; border:solid windowtext 1.0pt" width="198" | |
+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Middle ear impedance (1st dive)</span></span>'''</span> | ||
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+ | | style="width:69.4pt; border:solid windowtext 1.0pt" width="95" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">24 hours</span></span></span></p> | ||
+ | | style="width:69.35pt; border:solid windowtext 1.0pt" width="94" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">-5 daPa</span></span></span></p> | ||
+ | | style="width:69.4pt; border:solid windowtext 1.0pt" width="95" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">-17.5 daPa</span></span></span></p> | ||
+ | | style="width:87.3pt; border:solid windowtext 1.0pt" width="119" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">0.017</span></span></span></p> | ||
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+ | | style="width:146.35pt; border:solid windowtext 1.0pt" width="198" | | ||
+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Middle ear impedance (2nd dive)</span></span>'''</span> | ||
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+ | | style="width:69.4pt; border:solid windowtext 1.0pt" width="95" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">24 hours</span></span></span></p> | ||
+ | | style="width:69.35pt; border:solid windowtext 1.0pt" width="94" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">-2.5 daPa</span></span></span></p> | ||
+ | | style="width:69.4pt; border:solid windowtext 1.0pt" width="95" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">-7.5 daPa</span></span></span></p> | ||
+ | | style="width:87.3pt; border:solid windowtext 1.0pt" width="119" | <p align="center" style="margin-bottom:.0001pt; text-align:center; padding:.75pt .75pt .75pt .75pt"><span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">0.64</span></span></span></p> | ||
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− | + | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Comments:</span></span>'''</span> | |
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− | <span style="font-family: | + | <span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">1. Administration of vitamins was associated with significantly worse eustachian tube function- this finding was the reverse of that hypothesised.</span></span></span> |
− | <span style="font-family: | + | |
+ | <span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">2. The putative action of vitamins was to reduce free-radical mediated mucosal damage that might explain the development of negative middle ear pressures after oxygen diving.</span></span></span> | ||
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+ | <span style="line-height:normal"><span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">3. Report in abstract only</span></span></span> | ||
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+ | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Appraised by:</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Mike Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney; Sunday, 17 September 2000</span></span></span> | ||
− | + | <span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Expiry date:</span></span>'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">June 2022</span></span></span> | |
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− | [[File: | + | [[File:Sumhorsa.gif|center|Sumhorsa.gif]] |
− | <span style="display: block; text-align: center;"><span style="font-size: 29.9px;">[[Audiovestibular | + | <span style="display: block; text-align: center;"><span style="font-size: 29.9px;">[[Audiovestibular|BACK]]</span></span> |
Latest revision as of 01:53, 5 October 2021
Administration of free-radical scavengers (vitamins C and E) before oxygen diving did not improve eustachian tube ventilatory function.
Clinical Bottom Line:
1. Administration of vitamins C and E promoted rather than prevented negative ear pressures after oxygen diving.
2. The magnitude of the negative middle ear pressure was less after the second dive in both groups.
Citation/s:1. Mutzbauer T, Mueller P, Tetzlaff K et al. Is eustachian tube ventilatory function (ETVF) impairment after oxygen diving mediated by free radicals? Undersea and Hyperbaric Medicine 2000; 27(suppl):16.
Clinical Scenario:A diver exposed to hyperbaric oxygen displayed negative middle ear pressures.
Three-part Question:In divers using high inspired oxygen, does the administration of vitamins C and E, compared to placebo, prevent negative middle ear pressure after diving?
Search Terms:Middle ear, eustachian tube
The Study:Double-blinded concealed randomised controlled trial with intention-to-treat. Fit volunteer naval divers
Control group (N = 8; 8 analysed):Placebo medication at least three hours before diving (oxygen rebreather at 4m for 30 minutes average) on two consecutive days.
Experimental group (N = 7; 7 analysed):1g vitamin C and 600 IU of vitamin E at least three hours prior to diving (same exposure).
The Evidence:
Non-event outcomes |
Time to outcome |
Placebo group |
Vitamin group |
P-value |
Middle ear impedance (1st dive) |
24 hours |
-5 daPa |
-17.5 daPa |
0.017 |
Middle ear impedance (2nd dive) |
24 hours |
-2.5 daPa |
-7.5 daPa |
0.64 |
Comments:
1. Administration of vitamins was associated with significantly worse eustachian tube function- this finding was the reverse of that hypothesised.
2. The putative action of vitamins was to reduce free-radical mediated mucosal damage that might explain the development of negative middle ear pressures after oxygen diving.
3. Report in abstract only
Appraised by:Mike Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney; Sunday, 17 September 2000
Expiry date:June 2022