Page 7 - JCTR-10-5

Journal of Clinical and Translational Research 2024; 10(5): 269-282

Journal of Clinical and Translational Research

Journal homepage: http://www.jctres.com/en/home

ORIGINAL ARTICLE

A broad appraisal of decompression-induced physiological stress in
different simulated dive profiles

Sergio Rhein Schirato *, Ingrid El-Dash , Vivian El-Dash , Bruna Bizzarro , Alessandro Marroni , Massimo Pieri ,
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Danilo Cialoni , Jose Guilherme Chaui-Berlinck 1
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1 Department of Physiology, Biosciences Institute, University of São Paulo, São Paulo, Brazil, Peter Murányi Experimental Research Center,
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Albert Einstein Hospital, São Paulo, Brazil, DAN Europe Research Division, Roseto Degli Abruzzi, Italy, Environmental Physiology and
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Medicine Laboratory, Department of Biomedical Sciences, University of Padova, Padova, Italy
ARTICLE INFO ABSTRACT
Article history: Background: The present study was designed to observe if different decompression profiles,
Received: May 30, 2024 calculated as a function of tissue supersaturation during ascent, would result in significantly
Accepted: August 26, 2024 different outcomes, measured through different physiological stress indicators, even in the absence
Published Online: October 3, 2024 of symptoms of decompression sickness.
Aim: The aim of this study was to evaluate if simulated decompression profiles would affect the
Keywords: immune system, oxidative stress indicators, and heart rate variability.
Decompression Methods: A total of 23 volunteers participated in two different experimental protocols in a dry
Decompression sickness hyperbaric chamber. These simulated dives comprised two different compression–decompression
Immune system activation arrangements with the same maximum pressure and duration but different decompression profiles.
Microparticles Results: The shallow decompression profile with shorter deeper stops and longer shallow stops
Decompression profiles presented an increase in the standard deviation of the normal-to-normal R-R interval (a wide
indicator of overall variability); the deep decompression profile with longer deeper stops and shorter
*Corresponding author: shallow stops did not exhibit such increase. The shallow decompression profile resulted in an
Sergio Rhein Schirato increase in neutrophil count and its microparticles (MPs), but no changes were observed for platelet
Department of Physiology, Biosciences count and its MPs, as well as for endothelial-derived MPs. In contrast, the deep decompression
Institute, University of São Paulo, São Paulo, profile resulted in no changes in neutrophil count and its MPs, but a decrease in platelet count along
Brazil. Email: sergio.schirato@gmail.com with an increase in MPs from both platelets and endothelial cells. The observed difference might
be related to different levels of decompression-related activation of immune system responses and
© 2024 Author(s). This is an Open- oxidative processes triggered by different levels of inert gas supersaturation upon surfacing.
Access article distributed under the terms Conclusion: From previous results and literature data, we present a tentative schematic of how
of the Creative Commons Attribution- the velocity of ascent would trigger (or not) pro-inflammatory and immune system responses that
Noncommercial License, permitting all could ultimately lead to the development of decompression sickness.
non-commercial use, distribution, and
reproduction in any medium, provided the Relevance for patients: Increasing safety in exposure to hyperbaric environments and subsequent
original work is properly cited. decompression by evaluating individual physiological responses to the process.

1. Introduction

Exposure to hyperbaric environments and subsequent decompression has been
associated with many physiological alterations, which may culminate in decompression
sickness. This condition can manifest itself through a variety of symptoms [1], ranging
from joint and/or musculoskeletal pain [2], to cardiovascular and neurological impairment
and, ultimately, death. Historically, studies related to decompression have adopted a
binary approach in regard to decompression sickness [3], separating symptomatic and
asymptomatic events. There is, however, a huge spectrum of possible physiological
alterations between these two extremes, to which probabilities of decompression sickness
DOI: https://doi.org/10.36922/jctr.24.00021