M.bennett at 07:14, 10 April 2021

2021-04-10T07:14:22Z

M.bennett: Created page with " '''Enriched air nitrox reduced pulmonary artery bubble co..."

2021-04-10T06:58:20Z

Created page with " '''Enriched air nitrox reduced pulmonary artery bubble co..."

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'''Enriched air nitrox reduced pulmonary artery bubble counts and the rate of clinical DCS in volunteer divers.'''

{| class="Table" style="width:427.2pt; border:undefined" width="570"
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'''Clinical bottom line'''

'''1. Breathing enriched air nitrox reduced bubble counts at all time points. 2. There were fewer episodes of DCS in the EAN group.'''

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'''Citation/s:'''1.Souday V, Koning NJ, Perez B, Grelon F, Mercat A, Boer C, et al. (2016) Enriched Air Nitrox Breathing Reduces Venous Gas Bubbles after Simulated SCUBA Diving: A Double-Blind Cross-Over Randomized Trial. PLoS ONE 11(5): e0154761. [https://doi.org/10.1371/journal.pone.0154761 https://doi.org/10.1371/journal.pone.0154761] '''Lead author's name and fax: '''Pierre Asfar piasfar@chu-angers.fr

'''Three-part Clinical Question:'''For scuba divers, does breathing enriched air nitrox, compared to air, result in a reduction in decompression stress? '''Search Terms:''' Nitrox; bubble disease; doppler

'''The Study:'''Double-blinded randomised controlled trial with intention-to-treat. '''The Study Patients:''' Fit qualified divers with no h/o decompression sickness and who demonstrated bubble grades 2 or above on test compression. '''Control group''' (N = 12; 12 analysed): Air breathing for a compression to 28 metres of seawater (3.8 ATA) for 55 minutes with decompression stops at 6m and 3m. 5 minute exercise period on a static bicycle at depth. '''Experimental group''' (N = 12; 12 analysed): As above but breathing Nitrox 36 (36% oxygen and 64% nitrogen).

'''The Evidence:'''

{| class="Table" style="border:solid windowtext 1.0pt"
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| style="width:110.9pt; border:solid windowtext 1.0pt" width="148" | '''Outcome'''
| style="width:55.2pt; border:solid windowtext 1.0pt" width="74" | '''Time to Outcome'''
| style="width:48.15pt; border:solid windowtext 1.0pt" width="64" | '''Control dive'''
| style="width:33.9pt; border:solid windowtext 1.0pt" width="45" | '''EAN dive'''
| style="width:69.4pt; border:solid windowtext 1.0pt" width="93" | '''Relative risk reduction'''
| style="width:76.45pt; border:solid windowtext 1.0pt" width="102" | '''Absolute risk reduction'''
| style="width:44.8pt; border:solid windowtext 1.0pt" width="60" | '''NNT'''
|-
| rowspan="2" style="width:110.9pt; border:solid windowtext 1.0pt" width="148" |
'''Minor DCS (clinical diagnosis)'''

| style="width:55.2pt; border:solid windowtext 1.0pt" width="74" | '''1 hour'''
| style="width:48.15pt; border:solid windowtext 1.0pt" width="64" | '''0.25'''
| style="width:33.9pt; border:solid windowtext 1.0pt" width="45" | '''0'''
| style="width:69.4pt; border:solid windowtext 1.0pt" width="93" | '''100%'''
| style="width:76.45pt; border:solid windowtext 1.0pt" width="102" | '''0.25'''
| style="width:44.8pt; border:solid windowtext 1.0pt" width="60" | '''4'''
|-
| colspan="3" style="width:140.25pt; border:solid windowtext 1.0pt" width="187" | 95% CIs:
| style="width:69.4pt; border:solid windowtext 1.0pt; padding:.75pt .75pt .75pt .75pt" width="93" |  
| style="width:76.45pt; border:solid windowtext 1.0pt" width="102" | 0.005 to 0.5
| style="width:44.8pt; border:solid windowtext 1.0pt" width="60" | 2 to 200
|}

 

{| class="Table" style="border:solid windowtext 1.0pt"
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| style="width:118.0pt; border:solid windowtext 1.0pt" width="157" | '''Non-Event Outcomes'''
| style="width:97.75pt; border:solid windowtext 1.0pt" width="130" | '''Time to outcome/s'''
| style="width:69.35pt; border:solid windowtext 1.0pt" width="92" | '''Control group'''
| style="width:90.65pt; border:solid windowtext 1.0pt" width="121" | '''Experimental group'''
| style="width:66.05pt; border:solid windowtext 1.0pt" width="88" | '''P-value'''
|-
| style="width:118.0pt; border:solid windowtext 1.0pt" width="157" |
'''Bubble score (median[IQR])'''

| style="width:97.75pt; border:solid windowtext 1.0pt" width="130" | 30 minutes
| style="width:69.35pt; border:solid windowtext 1.0pt" width="92" | 2 [1–3]
| style="width:90.65pt; border:solid windowtext 1.0pt" width="121" | 0 [0–1]
| style="width:66.05pt; border:solid windowtext 1.0pt" width="88" | 0.008
|}

'''Comments:''' 1. Study based on the assumption that bubble numbers detected correlate with decompression stress and the chance of clinical decompression sickness. 2. All exposures took place in a hyperbaric chamber rather than immersed. 3. 47 divers had a test compression in the chamber (profile unknown) and 12 of these were selected for the study because of high bubble grades (>or= to Grade 2 - bubbles in 25 to 50% of cardiac cycles). 4. Block randomisation in groups of four and a crossover design. Divers and assessors were blinded to exposure. 5. Planned to do 17 divers but stopped at 12 as they found a difference in the primary outcome. 6. Bubble numbers reduced at all time points after the dive (30, 60, 90 minutes) when breathing Nitrox. 7. 14 total DCS incidences including the initial selection dives. Mostly cutaneous itching. '''Appraised by:'''Mike Bennett m.bennett@unsw.edu.au; Saturday, 10 April 2021 '''Kill or Update By:''' April 2023

← Older revision		Revision as of 07:14, 10 April 2021
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	<span style="line-height:normal">'''<span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">Comments:</span></span></span>'''<br/> <span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">1. Study based on the assumption that bubble numbers detected correlate with decompression stress and the chance of clinical decompression sickness.<br/> 2. All exposures took place in a hyperbaric chamber rather than immersed.<br/> 3. 47 divers had a test compression in the chamber (profile unknown) and 12 of these were selected for the study because of high bubble grades (>or= to Grade 2 - bubbles in 25 to 50% of cardiac cycles).<br/> 4. Block randomisation in groups of four and a crossover design. Divers and assessors were blinded to exposure.<br/> 5. Planned to do 17 divers but stopped at 12 as they found a difference in the primary outcome.<br/> 6. Bubble numbers reduced at all time points after the dive (30, 60, 90 minutes) when breathing Nitrox.<br/> 7. 14 total DCS incidences including the initial selection dives. Mostly cutaneous itching.</span></span></span></span> '''<span style="font-size:13.5pt"><span style="line-height:107%"><span style="font-family:"><span style="color:black">Appraised by:</span></span></span></span>'''<span style="font-size:13.5pt"><span style="line-height:107%"><span style="font-family:"><span style="color:black">Mike Bennett m.bennett@unsw.edu.au; Saturday, 10 April 2021<br/> '''Kill or Update By:''' April 2023</span></span></span></span>		<span style="line-height:normal">'''<span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">Comments:</span></span></span>'''<br/> <span style="font-size:13.5pt"><span style="font-family:"><span style="color:black">1. Study based on the assumption that bubble numbers detected correlate with decompression stress and the chance of clinical decompression sickness.<br/> 2. All exposures took place in a hyperbaric chamber rather than immersed.<br/> 3. 47 divers had a test compression in the chamber (profile unknown) and 12 of these were selected for the study because of high bubble grades (>or= to Grade 2 - bubbles in 25 to 50% of cardiac cycles).<br/> 4. Block randomisation in groups of four and a crossover design. Divers and assessors were blinded to exposure.<br/> 5. Planned to do 17 divers but stopped at 12 as they found a difference in the primary outcome.<br/> 6. Bubble numbers reduced at all time points after the dive (30, 60, 90 minutes) when breathing Nitrox.<br/> 7. 14 total DCS incidences including the initial selection dives. Mostly cutaneous itching.</span></span></span></span> '''<span style="font-size:13.5pt"><span style="line-height:107%"><span style="font-family:"><span style="color:black">Appraised by:</span></span></span></span>'''<span style="font-size:13.5pt"><span style="line-height:107%"><span style="font-family:"><span style="color:black">Mike Bennett m.bennett@unsw.edu.au; Saturday, 10 April 2021<br/> '''Kill or Update By:''' April 2023</span></span></span></span>
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Souday - Revision history

M.bennett at 07:14, 10 April 2021

M.bennett: Created page with " '''Enriched air nitrox reduced pulmonary artery bubble co..."