Measuring whole body inert gas wash-out
Plogmark, Oscar LU ; Silvanius, Mårten ; Olsson, Max LU
; Hjelte, Carl
LU
; Ekström, Magnus
LU
and Frånberg, Oskar
LU
(2023)
In Diving and Hyperbaric Medicine
53(4).
p.321-326
- Abstract
Introduction: Quantifying inert gas wash-out is crucial to understanding the pathophysiology of decompression sickness. In this study, we developed a portable closed-circuit device for measuring inert gas wash-out and validated its precision and accuracy both with and without human subjects. Methods: We developed an exhalate monitor with sensors for volume, temperature, water vapor and oxygen. Inert gas volume was extrapolated from these inputs using the ideal gas law. The device's ability to detect volume differences while connected to a breathing machine was analysed by injecting a given gas volume eight times. One hundred and seventy-two coupled before-and-after measurements were then compared with a paired t-test. Drift in measured... (More)
Introduction: Quantifying inert gas wash-out is crucial to understanding the pathophysiology of decompression sickness. In this study, we developed a portable closed-circuit device for measuring inert gas wash-out and validated its precision and accuracy both with and without human subjects. Methods: We developed an exhalate monitor with sensors for volume, temperature, water vapor and oxygen. Inert gas volume was extrapolated from these inputs using the ideal gas law. The device's ability to detect volume differences while connected to a breathing machine was analysed by injecting a given gas volume eight times. One hundred and seventy-two coupled before-and-after measurements were then compared with a paired t-test. Drift in measured inert gas volume during unlabored breathing was evaluated in three subjects at rest using multilevel linear regression. A quasi-experimental cross-over study with the same subjects was conducted to evaluate the device's ability to detect inert gas changes in relation to diving interventions and simulate power. Results: The difference between the injected volume (1,996 ml) and the device's measured volume (1,986 ml) was -10 ml. The 95% confidence interval (CI) for the measured volume was 1,969 to 2,003 ml. Mean drift during a 43 min period of unlaboured breathing was -19 ml, (95% CI, -37 to -1). Our power simulation, based on a cross-over study design, determined a sample size of two subjects to detect a true mean difference of total inert gas wash-out volume of 100 ml. Conclusions: We present a portable device with acceptable precision and accuracy to measure inert gas wash-out differences that may be physiologically relevant in the pathophysiology of decompression sickness.
(Less)
- author
- Plogmark, Oscar
LU
; Silvanius, Mårten
; Olsson, Max
LU
; Hjelte, Carl
LU
; Ekström, Magnus
LU
and Frånberg, Oskar
LU
- organization
- publishing date
- 2023-12
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Decompression sickness, Diving research, Gas kinetics, Nitrogen, Physiology, Pressure
- in
- Diving and Hyperbaric Medicine
- volume
- 53
- issue
- 4
- pages
- 6 pages
- publisher
- South Pacific Underwater Med Soc
- external identifiers
-
- pmid:38091591
- scopus:85179650414
- ISSN
- 1833-3516
- DOI
- 10.28920/dhm53.4.321-326
- language
- English
- LU publication?
- yes
- id
- 661394c6-770b-4865-9279-ef0e4aa59c5c
- date added to LUP
- 2024-01-03 13:15:03
- date last changed
- 2024-04-18 10:37:44
@article{661394c6-770b-4865-9279-ef0e4aa59c5c,
abstract = {{<p>Introduction: Quantifying inert gas wash-out is crucial to understanding the pathophysiology of decompression sickness. In this study, we developed a portable closed-circuit device for measuring inert gas wash-out and validated its precision and accuracy both with and without human subjects. Methods: We developed an exhalate monitor with sensors for volume, temperature, water vapor and oxygen. Inert gas volume was extrapolated from these inputs using the ideal gas law. The device's ability to detect volume differences while connected to a breathing machine was analysed by injecting a given gas volume eight times. One hundred and seventy-two coupled before-and-after measurements were then compared with a paired t-test. Drift in measured inert gas volume during unlabored breathing was evaluated in three subjects at rest using multilevel linear regression. A quasi-experimental cross-over study with the same subjects was conducted to evaluate the device's ability to detect inert gas changes in relation to diving interventions and simulate power. Results: The difference between the injected volume (1,996 ml) and the device's measured volume (1,986 ml) was -10 ml. The 95% confidence interval (CI) for the measured volume was 1,969 to 2,003 ml. Mean drift during a 43 min period of unlaboured breathing was -19 ml, (95% CI, -37 to -1). Our power simulation, based on a cross-over study design, determined a sample size of two subjects to detect a true mean difference of total inert gas wash-out volume of 100 ml. Conclusions: We present a portable device with acceptable precision and accuracy to measure inert gas wash-out differences that may be physiologically relevant in the pathophysiology of decompression sickness.</p>}},
author = {{Plogmark, Oscar and Silvanius, Mårten and Olsson, Max and Hjelte, Carl and Ekström, Magnus and Frånberg, Oskar}},
issn = {{1833-3516}},
keywords = {{Decompression sickness; Diving research; Gas kinetics; Nitrogen; Physiology; Pressure}},
language = {{eng}},
number = {{4}},
pages = {{321--326}},
publisher = {{South Pacific Underwater Med Soc}},
series = {{Diving and Hyperbaric Medicine}},
title = {{Measuring whole body inert gas wash-out}},
url = {{http://dx.doi.org/10.28920/dhm53.4.321-326}},
doi = {{10.28920/dhm53.4.321-326}},
volume = {{53}},
year = {{2023}},
}