M.bennett at 07:04, 21 December 2020

2020-12-21T07:04:20Z

M.bennett at 06:58, 21 December 2020

2020-12-21T06:58:57Z

M.bennett: Created page with " '''50% oxygen breathing..."

2020-12-21T06:58:03Z

Created page with " '''50% oxygen breathing..."

New page

'''50% oxygen breathing during decompression, but not 99% oxygen breathing, was associated with significantly reduced flow-mediated dilatation in the brachial artery.'''

 

'''Clinical bottom line'''

{| class="Table" style="width:467.55pt; border:none" width="0"
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| style="width:464.55pt; border:none" width="623" |
'''1. 99% reduced the bubble numbers after provocation 2. 50% oxygen decompression reduced FMD compared to either of the other breathing gases.'''

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'''Citation/s:'''1.Ribicic IŠ, Valic M, Božic J, Obad A, Glavaš D, Glavicic I, Valic Z. Influence of oxygen enriched gases during decompression on bubble formation and endothelial function in self-contained underwater breathing apparatus diving: a randomized controlled study. Croatian medical journal. 2019 Jun;60(3):265.  

'''Three-part Clinical Question:'''For rebreather divers, does altering the proportion of oxygen in the breathing gas result in any differences in venous bubbling or endothelial function? '''Search Terms:''' Rebreather; nitrrox; venous gas embolism

'''The Study:'''Non-blinded randomised controlled trial with intention-to-treat. '''The Study Patients:''' Fit adult experienced divers with no significant comorbidities or history of decompression illness. '''Control group''' (N = 10; 10 analysed): Air dive to 45msw with V-planner calculated decompression stops on air for a total dive time of 65 minutes. '''Experimental group''' (N = 10; 10 analysed): Same bottom time and depth but V-planner calculated decompression stops with 50% oxygen (from 21 msw, total dive time 45 mins) and 99% oxygen (from 6 msw and total dive time 43 mons).

'''The Evidence:'''

 

{| class="Table" style="border:solid windowtext 1.0pt"
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| rowspan="2" style="width:158.25pt; border:solid windowtext 1.0pt" width="214" | '''Measure'''
| colspan="2" style="width:66.25pt; border:solid windowtext 1.0pt" width="90" | '''Air Group'''
| colspan="2" style="width:68.1pt; border:solid windowtext 1.0pt" width="93" | '''50% oxygen Group'''
| rowspan="2" style="width:61.65pt; border:solid windowtext 1.0pt" width="84" | '''Difference'''
| rowspan="2" style="width:87.55pt; border:solid windowtext 1.0pt" width="120" | '''95% CI'''
|-
| style="width:31.85pt; border:solid windowtext 1.0pt" width="44" | '''Mean'''
| style="width:32.9pt; border:solid windowtext 1.0pt" width="46" | '''SD'''
| style="width:33.7pt; border:solid windowtext 1.0pt" width="47" | '''Mean'''
| style="width:32.9pt; border:solid windowtext 1.0pt" width="46" | '''SD'''
|-
| style="width:158.25pt; border:solid windowtext 1.0pt" width="214" |
'''Flow mediated vasodilatation (%) at 30 mins'''

| style="width:31.85pt; border:solid windowtext 1.0pt" width="44" | 8.14
| style="width:32.9pt; border:solid windowtext 1.0pt" width="46" | 3.61
| style="width:33.7pt; border:solid windowtext 1.0pt" width="47" | 3.62
| style="width:32.9pt; border:solid windowtext 1.0pt" width="46" | 5.57
| style="width:61.65pt; border:solid windowtext 1.0pt" width="84" | 4.5
| style="width:87.55pt; border:solid windowtext 1.0pt" width="120" | -16.2 to 25.2
|}

 

{| class="Table" style="border:solid windowtext 1.0pt"
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| style="border:solid windowtext 1.0pt" | '''Non-Event Outcomes'''
| style="border:solid windowtext 1.0pt" | '''Time to outcome/s'''
| style="border:solid windowtext 1.0pt" | '''Control group'''
| style="border:solid windowtext 1.0pt" | '''Experimental group'''
| style="border:solid windowtext 1.0pt" | '''P-value'''
|-
| style="border:solid windowtext 1.0pt" |
'''Bubble Grade after provocation with cough (Eftedal and Brubakk score)'''

| style="border:solid windowtext 1.0pt" | 30 mins
| style="border:solid windowtext 1.0pt" | 3
| style="border:solid windowtext 1.0pt" | 1
| style="border:solid windowtext 1.0pt" | 0.026
|}

'''Comments:''' 1. Ten individuals did the three dives in a random order with one day off between each dive. 2. Brachial arterial flow mediated dilatation (FMD) was measured using % dilatation after a five minute occlusion of flow. 3, Bubble grade data analysed by Friedman repeated measures analysis of variance. 4. FMD difference was statistically significant between 50% oxygen and either of the other two conditions by two way repeated measures ANOVA with Tukey test, P=0.03 in the paper. 5. The FMD was expected to decrease further with 99% oxygen than 50% oxygen so this finding is surprising.

'''Appraised by:'''Mike Bennett m.bennett@unsw.edu.au; Monday, 21 December 2020 '''Kill or Update By:''' December 2022

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	<span style="line-height:normal">'''<span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">Appraised by:</span></span></span>'''<span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">Mike Bennett m.bennett@unsw.edu.au; Monday, 21 December 2020<br/> '''Kill or Update By:''' December 2022</span></span></span></span>		<span style="line-height:normal">'''<span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">Appraised by:</span></span></span>'''<span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">Mike Bennett m.bennett@unsw.edu.au; Monday, 21 December 2020<br/> '''Kill or Update By:''' December 2022</span></span></span></span>
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Ribicic - Revision history

M.bennett at 07:04, 21 December 2020

M.bennett at 06:58, 21 December 2020

M.bennett: Created page with " '''50% oxygen breathing..."