Human Adaptation During Hypobaric Hypoxia Exposure

Human Adaptation During Hypobaric Hypoxia Exposure

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Description: Bioimpedance Cardiac Output Monitoring As A Predictor For Hypoxia Resistance - Our altitude chamber has been fitted with a poliphysiological recording device. We have used it to collect and interpret data regarding human adaptation during hypobaric hypoxia exposure. METHOD - Chamber flights were performed between 8.30 am and 12.30 am with standard rest and nutrition requirements, Simulated flight took 15 minutes, Climbs up to 5500 meters at 40 m/s speed, In minute 7 there was a physical stress t.

 
Author: D Vlad, A Macovei, I Capanu, D Popescu, and A Raicu (Fellow) | Visits: 1366 | Page Views: 3207
Domain:  Medicine Category: Biotech/Pharma Subcategory: R&D 
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Contents:
BIOIMPEDANCE CARDIAC OUTPUT MONITORING AS A PREDICTOR FOR HYPOXIA RESISTANCE

Authors: D VLAD, A MACOVEI, I CAPANU, D POPESCU, A RAICU

NATIONAL INSTITUTE OF AEROSPACE MEDICINE Bucharest, ROMANIA



Our altitude chamber has been fitted with a poliphysiological recording device. We have used it to collect and interpret data regarding human adaptation during hypobaric hypoxia exposure.

PURPOSE AND METHOD

Resistance and training evaluation by hypobaric exposure remains one of main tools in selection and training of the flying crew
Simultaneous recordings of the modules ECG, BIOIMPEDANCE and PLETHYSMOGRAPHY from a poliphysiograf allowed us to gather relevant data for hypobaric resistance evaluation; We monitored:


- Correlations regarding hypobaric hypoxia resistance in chamber flight as appreciated by heart rate (HR), oxygen saturation (OS), stroke volume (SV) and cardiac output (CO) - Differences between smokers and non smokers

METHOD








Chamber flights were performed between 8.30 am and 12.30 am with standard rest and nutrition requirements Simulated flight took 15 minutes Climbs up to 5500 meters at 40 m/s speed In minute 7 there was a physical stress test on a treadmill for 20s at 20m/s speed Descent was made at 30 m/s speed Real time on-line monitoring of bioimpedance, ECG, pulse wave, oxygen saturation, altitude, temperature and relative humidity. Two types of subjects: candidates for pilot status and professional pilots

Recorded phases
Ground 5500 m Before effort Effort Compensation after effort Descent


STANDARD BIOIMPEDANCE ELECTRODE PLACEMENT

RESULTS AND DISCUSSIONS

Histogram of multiple variables Statistica Bioimpedanta 28v*100c 50 45 40 35 30

No of obs

25 20 15 10 5 0 0 2 4 6 8 10 12 14 16 18 20 CO CO CO CO CO CO ground at 5500 m before effort durring effort after effort descent

Histogram of multiple variables Statistica Bioimpedanta 28v*100c 45 40 35 30

No of obs

25 20 15 10 5 0 50 60 70 80 90 100 110 120 130 140 150 160 HR ground HR at 5500 m HR before effort HR during effort HR after effort HR descent

Histogram of multiple variables Statistica Bioimpedanta 28v*100c 120

100

80

No of obs

60

40

20

0 65 70 75 80 85 90 95 100 105

OS OS OS OS OS OS

ground at 5500 m before effort during effort after effort descent

Histogram of multiple variables Statistica Bioimpedanta 28v*100c 45 40 35 30

No of obs

25 20 15 10 5 0 20 40 60 80 100 120 140 160 180 SV SV SV SV SV SV ground at 5500 m before effort during effort after effort descent

Mean Plot of multiple variables Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 11,0 10,5 10,0 9,5 9,0 8,5 8,0 7,5 7,0 6,5

CO at 5500 m

CO durring effort

CO before effort

CO after effort

CO descent

CO ground

Mean Mean�0,95 Conf. Interval

Mean Plot of multiple variables Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 125 120 115 110 105 100 95 90 85 80 75

HR at 5500 m

HR before effort

HR during effort

HR after effort

HR descent

HR ground

Mean Mean�0,95 Conf. Interval

Mean Plot of multiple variables Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 100 98 96 94 92 90 88 86 84 82 80 78 76 74

OS at 5500 m

OS before effort

OS during effort

OS after effort

OS descent

OS ground

Mean Mean�0,95 Conf. Interval

Mean Plot of multiple variables Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 94 92 90 88 86 84 82 80 78 76 74 72

SV at 5500 m

SV before effort

SV during effort

SV after effort

SV descent

SV ground

Mean Mean�0,95 Conf. Interval

Mean Plot of multiple variables grouped by Smoker Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 11,5 11,0 10,5 10,0 9,5 9,0 8,5 8,0 7,5 CO ground: F(1;98) = 0,5589; p = 0,4565 7,0 CO at 5500 m: F(1;98) = 0,6513; p = 0,4216 CO before effort: F(1;98) = 0,0433; p = 0,8355 6,5 CO durring effort: F(1;98) = 1,6738; p = 0,1988 N CO after effort: F(1;98) = 0,3271; p = 0,5687 Smoker CO descent: F(1;98) = 0,1138; p = 0,7366 CO CO CO CO CO CO ground at 5500 m before effort durring effort after effort descent

Y

Mean Plot of multiple variables grouped by Smoker Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 130

120

110

100

90

80 HR ground: F(1;98) = 5,5229; p = 0,0208 HR at 5500 m: F(1;98) = 2,2659; p = 0,1355 HR before effort: F(1;98) = 1,1215; p = 0,2922 70 HR during effort: F(1;98) = 0,9108; p = 0,3423 N HR after effort: F(1;98) = 2,2383; p = 0,1378 Smoker HR descent: F(1;98) = 0,116; p = 0,7341

Y

HR ground HR at 5500 m HR before effort HR during effort HR after effort HR descent

Mean Plot of multiple variables grouped by Smoker Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 100

95

90

85

80

75

70 SV ground: F(1;98) = 0,1973; p = 0,6579 SV at 5500 m: F(1;98) = 0,0099; p = 0,9208 SV before effort: F(1;98) = 0,2219; p = 0,6386 65 SV during effort: F(1;98) = 3,1549; p = 0,0788 N SV after effort: F(1;98) = 0,2225; p = 0,6382 Smoker SV descent: F(1;98) = 0,0605; p = 0,8062

Y

SV SV SV SV SV SV

ground at 5500 m before effort during effort after effort descent

Mean Plot of multiple variables grouped by Smoker Statistica Bioimpedanta 28v*100c Mean; Whisker: Mean�0,95 Conf. Interval 100 98 96 94 92 90 88 86 84 82 80 78 OS ground: F(1;98) = 4,2226; p = 0,0426 OS at 5500 m: F(1;98) = 0,6905; p = 0,4080 76 OS before effort: F(1;98) = 2,9683; p = 0,0881 74 OS during effort: F(1;98) = 0,0087; p = 0,9257 N OS after effort: F(1;98) = 0,8975; p = 0,3458 Smoker OS descent: F(1;98) = 2,8456; p = 0,0948 OS OS OS OS OS OS ground at 5500 m before effort during effort after effort descent

Y

Scatterplot of multiple variables against CO ground Statistica Bioimpedanta 28v*100c HR ground = 41,6671+48,2125*log10(x) SV ground = -29,4548+139,7603*log10(x) 140 130 120 110 100 90 80 70 60 50 40 CO ground:HR ground: y = 57,2763 + 3,4568*x; 30 r = 0,4904; 3 = 0,00000 5 p 2 4 6 7 8 CO ground:SV ground: y = 24,0801 + 8,8814*x; CO ground r = 0,7973; p = 0.0000 9 10 11 12

HR ground SV ground

Scatterplot of multiple variables against CO at 5500 m Statistica Bioimpedanta 28v*100c HR at 5500 m = 68,3506+29,9579*log10(x) SV at 5500 m = -47,9288+149,4826*log10(x) 140

120

100

80

60

40 CO at 5500 m:HR at 5500 m: y = 78,6127 + 2,0393*x; 20 r = 0,3294; 4 = 0,0008 6 p 3 5 7 8 9 10 CO at 5500 m:SV at 5500 m: y = 14,9619 + 8,7372*x; CO at 5500 m r = 0,8361; p = 0.0000

11

12

13

HR at 5500 m SV at 5500 m

Scatterplot of multiple variables against CO before effort Statistica Bioimpedanta 28v*100c HR before effort = 77,1825+28,8652*log10(x) SV before effort = -63,2942+160,0058*log10(x) 160 140 120 100 80 60 40 20 CO before effort:HR before effort: y = 90,3705 + 1,5408*x; 0 r = 0,3173; p = 0,0013 6 2 4 8 10 12 CO before effort:SV before effort: y = 11,9411 + 8,3008*x; CO before effort r = 0,8978; p = 0.0000

14

16

HR before effort SV before effort

Scatterplot of multiple variables against CO durring effort Statistica Bioimpedanta 28v*100c HR during effort = 100,014+21,2355*log10(x) SV during effort = -81,9494+167,8509*log10(x) 160 140 120 100 80 60 40 20 0 CO durring 2 r = 0,1917; CO durring

effort:HR during effort: y = 112,7359 + 0,8164*x; 4 6 8 10 12 14 16 18 HR during effort p = 0,0560 CO y = 2,4259 + SV effort:SV during effort: durring effort 8,0715*x; r = 0,9192; p = 0.0000 during effort

Scatterplot of multiple variables against CO after effort Statistica Bioimpedanta 28v*100c HR after effort = 101,3263+16,5385*log10(x) SV after effort = -72,8017+161,8909*log10(x) 180 160 140 120 100 80 60 40 20 0 CO after effort:HR after effort: y = 8 109,527110 0,8075*x; + 2 4 6 12 14 16 r = 0,1264; p = 0,2100 CO after + 8,3788*x; r = 0,8317; p = 0.0000 CO after effort:SV after effort: y = 2,8283 effort

HR after effort SV after effort

Scatterplot of multiple variables against CO descent Statistica Bioimpedanta 28v*100c HR descent = 105,7611-1,3472*log10(x) SV descent = -74,8273+172,1083*log10(x) 160 140 120 100 80 60 40 20 CO descent:HR descent: y = 106,8285 - 0,2813*x; 0 r = -0,0432; p = 0,6695 6 2 4 8 10 CO descent:SV descent: y = -5,1726 + 10,3912*x; CO descent r = 0,8791; p = 0.0000

12

14

16

HR descent SV descent

CONCLUSIONS





It is possible to make a pattern between SV and HR dynamic for a better understanding of hypobaric hypoxia tolerance. This could be a motivation for further researches, and would enable as to have some hypoxia resistance normograms. The HR is the main contributor to CO compensation during effort, but altitude adaptation involves changes to SV. HR and SV has no significant difference between smokers and non smokers, but OS is better correlated.

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