Difference between revisions of "Mutzbauer"

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'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Administration of free-radical scavengers (vitamins C and E) before oxygen diving did not improve eustachian tube ventilatory function.</span>'''
 
  
<span style="border-color: windowtext; border-style: solid; border-width: 1.5pt; display: block; padding: 1pt 4pt;">
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<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>
<span style="padding-bottom: 0cm; padding-left: 0cm; padding-right: 0cm; padding-top: 0cm;">'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Clinical Bottom Line:</span>'''
 
<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">1. Administration of vitamins C and E promoted negative middle ear pressures after oxygen diving.
 
2. The magnitude of middle ear negative pressure was less after the second dive in both groups.</span></span>
 
</span>
 
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Appraised by:</span>'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;"> Mike Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital, Sydney; Sunday, 17 September 2000</span>
 
  
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Clinical Scenario:</span>'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;"> A diver exposed to hyperbaric oxygen displayed negative middle ear pressures.</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>
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Three-part Question:</span>'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;"> 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 style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Search Terms:</span>'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;"> Middle ear, eustachian tube</span>
 
  
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">The Study:</span>'''
+
<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>
<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Double-blinded concealed randomised controlled trial with intention-to-treat.</span>
 
<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Fit volunteer naval divers</span>
 
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Control group</span>'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;"> (N = 8; 8 analysed): Placebo medication at least three hours before diving (oxygen rebreather at 4m for 30 minutes average) on two consecutive days. </span>
 
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Experimental group</span>'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;"> (N = 7; 7 analysed): 1g vitamin C and 600 IU of vitamin E at least three hours prior to diving (same exposure).</span>
 
  
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">The Evidence:</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>
{|
+
 
| <span style'''"line-height: normal; margin-bottom: 0pt;">'''Non-event outcomes'''</span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">'''Time to outcome'''</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">'''Placebo group'''</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">'''Vitamin group'''</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style="display: block; text-align: center;">'''P-value'''</span></span>  
+
----
 +
 
 +
<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>
 +
 
 +
<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>
 +
 
 +
<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>
 +
 
 +
<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>
 +
 
 +
<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>
 +
 
 +
<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>
 +
 
 +
<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>
 +
 
 +
<span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">The Evidence:</span></span>'''</span>
 +
 
 +
{| class="Table" style="border:solid windowtext 1.0pt"
 
|-
 
|-
| <span style'''"line-height: normal; margin-bottom: 0pt;">'''Middle ear impedance (1st dive)'''</span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">24 hours</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">-5 daPa</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">-17.5 daPa</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style="display: block; text-align: center;">0.017</span></span>  
+
| 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>  
 
|-
 
|-
| <span style'''"line-height: normal; margin-bottom: 0pt;">'''Middle ear impedance (2nd dive)'''</span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">24 hours</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">-2.5 daPa</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style'''"display: block; text-align: center;">-7.5 daPa</span></span> || <span style'''"display: block; line-height: normal; margin-bottom: 0pt; text-align: center;"><span style="display: block; text-align: center;">0.64</span></span>  
+
| 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>
 +
 
 +
| 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>  
 
|-
 
|-
 +
| 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>
 +
 +
| 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>
 
|}
 
|}
  
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Comments:</span>'''
+
<span style="line-height:normal">'''<span style="font-size:12.0pt"><span style="font-family:" times="" new="" roman",serif"="">Comments:</span></span>'''</span>
<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">1. Administration of vitamins was associated with significantly worse eustachian tube function- this finding was the reverse of that hypothesised.</span>
+
 
<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">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 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: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">3. Report in abstract only</span>
+
 
 +
<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>
 +
 
 +
<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>
 +
 
 +
<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="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">Expiry date:</span>'''<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;"> June 2020</span>
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<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>
**<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">References: </span>'''
 
<span style="font-family: &#39;Times New Roman&#39;,&#39;serif&#39;; font-size: 16px;">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>
 
  
[[File:sumhorsa.gif|center]]
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[[File:Sumhorsa.gif|center|Sumhorsa.gif]]
  
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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

Sumhorsa.gif

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