M.bennett at 05:37, 31 January 2022

2022-01-31T05:37:43Z

M.bennett: Created page with " '''Possible reduction in core temperature but not of energy expenditure when breathing FiO₂ 0.13..."

2022-01-31T05:32:34Z

Created page with " '''Possible reduction in core temperature but not of energy expenditure when breathing FiO2 0.13..."

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'''Possible reduction in core temperature but not of energy expenditure when breathing FiO2 0.13 compared to FiO2 0.21 during head-out cold-water immersion.'''

 

'''Clinical bottom line:'''

#No difference in energy expenditure in normobaric cold-water immersion between breathing a hypoxic mixture (FiO2 0.13) compared to air.
#Possible small reduction in rectal temperature after the hypoxic exposure (see comments).

----

'''Citation:'''Keeler JM, Greenshields JT, Goss CS, Baker TB, Chapman RF, Johnson BD, Schlader ZJ. Modification of thermoregulation during cold-water immersion by normobaric hypoxia. Undersea and Hyperbaric Medical Society. 2021, 4(3):344-345.

'''Lead author’s name and email:'''J. M. Keeler : jmkeeler@iu.edu

 

'''Three-part clinical question:'''For head-out cold-water (22°C) immersion in normobaric conditions, does a period breathing FiO2 0.13 compared to breathing FiO2 0.21 (air), result in decreased energy expenditure and core temperature?

'''Search terms:'''Thermoregulation, normobaric hypoxia, cold-water immersion

 

'''The study:'''Non-blinded randomised crossover trial with intention to treat.

'''The study patients:'''Nine healthy adult volunteers at 27±4 years.

'''Control group:'''(N = 9; 9 analysed): Head-out cold-water (22°C) immersion in normobaric conditions for up to an hour breathing a normoxic mixture (FiO2 = 0.21).

'''Experimental group:'''(N = 9; 9 analysed): As above, but instead breathing a hypoxic mixture (FiO2 = 0.13).

 

'''The Evidence:'''

{| class="Table" style="border: 1pt solid windowtext; width: 792px;"
|-
| rowspan="2" style="width: 252px; border: 1pt solid windowtext;" width="217" | '''Measure'''
| colspan="2" style="width: 110px; border: 1pt solid windowtext;" width="85" | '''Air exp.'''
| colspan="2" style="width: 115px; border: 1pt solid windowtext;" width="95" | '''Hypoxia exp'''
| rowspan="2" style="width: 120px; border: 1pt solid windowtext;" width="76" | '''Difference'''
| rowspan="2" style="width: 154px; border: 1pt solid windowtext;" width="129" | '''95% CI'''
|-
| style="width: 56px; border: 1pt solid windowtext;" width="47" | '''Mean'''
| style="width: 56px; border: 1pt solid windowtext;" width="38" | '''SD'''
| style="width: 45px; border: 1pt solid windowtext;" width="44" | '''Mean'''
| style="width: 63px; border: 1pt solid windowtext;" width="51" | '''SD'''
|-
| style="width: 252px; border: 1pt solid windowtext;" width="217" |
'''Rectal temperature (oC) at end of exposure'''

| style="width: 56px; border: 1pt solid windowtext;" width="47" | 36.7
| style="width: 56px; border: 1pt solid windowtext;" width="38" | 0.5
| style="width: 45px; border: 1pt solid windowtext;" width="44" | 36.4
| style="width: 63px; border: 1pt solid windowtext;" width="51" | 0.5
| style="width: 120px; border: 1pt solid windowtext;" width="76" | 0.3
| style="width: 154px; border: 1pt solid windowtext;" width="129" | 0.05 to 0.55
|-
| style="width: 252px; border: 1pt solid windowtext;" width="217" |
'''Energy expenditure (kilojoules)'''

'''(unit time not given)'''

| style="width: 56px; border: 1pt solid windowtext;" width="47" | 11.8
| style="width: 56px; border: 1pt solid windowtext;" width="38" | 2.8
| style="width: 45px; border: 1pt solid windowtext;" width="44" | 13.1
| style="width: 63px; border: 1pt solid windowtext;" width="51" | 4.2
| style="width: 120px; border: 1pt solid windowtext;" width="76" | 1.3
| style="width: 154px; border: 1pt solid windowtext;" width="129" | -11.4 to 14.0
|}

 

'''Comments'''

#Abstract in conference proceedings only so many details missing. Waiting for the authors’ full account. Exposures were ‘up to 1 hour’ – the authors have not reported actual durations of exposure.
#Small sample size of 9 individuals, no power calculation available.
#Using the published figures, we conclude the difference in rectal temperatures was statistically significantly lower in hypoxia exposure but this may be a misinterpretation (figures may be within group).
#Between group differences in trapezius and supraclavicular sites were not statistically different.
#The average arterial oxygen saturation in the hypoxic group was 90% versus 99% with normoxia.

 

'''Appraised by: '''Bosco Tran bosco.tran@student.unsw.edu.au

'''Kill or update by''': January 2024

@@ Line 13: / Line 13: @@
 '''<span style="font-size:12.0pt"><span style="line-height:107%">Citation:</span></span>'''<span style="font-size:12.0pt"><span style="line-height:107%">Keeler JM, Greenshields JT, Goss CS, Baker TB, Chapman RF, Johnson BD, Schlader ZJ. Modification of thermoregulation during cold-water immersion by normobaric hypoxia. Undersea and Hyperbaric Medical Society. 2021, 4(3):344-345.</span></span>
-'''<span style="font-size:12.0pt"><span style="line-height:107%">Lead author’s name and email:</span></span>'''<span style="font-size:12.0pt"><span style="line-height:107%">J. M. Keeler : jmkeeler@iu.edu</span></span>
+'''<span style="font-size:12.0pt"><span style="line-height:107%">Lead author’s name and email:</span></span>'''<span style="font-size:12.0pt"><span style="line-height:107%">J. M. Keeler&nbsp;: jmkeeler@iu.edu</span></span>
 &nbsp;
@@ Line 86: / Line 86: @@
 '''<span style="font-size:12.0pt"><span style="line-height:107%">Kill or update by</span></span>'''<span style="font-size:12.0pt"><span style="line-height:107%">: January 2024</span></span>

Keeler - Revision history

M.bennett at 05:37, 31 January 2022

M.bennett: Created page with " '''Possible reduction in core temperature but not of energy expenditure when breathing FiO2 0.13..."

M.bennett: Created page with " '''Possible reduction in core temperature but not of energy expenditure when breathing FiO₂ 0.13..."