Related Experiment Video
Updated: May 9, 2026
06:00
Modeling Highly Repetitive Low-level Blast Exposure in Mice
Published on: May 24, 2024
Probability of hypobaric decompression sickness including extreme exposures
Johnny Conkin1, Michael L Gernhardt, Andrew F Abercromby
1Universities Space Research Association, Houston, TX 77058-2769, USA. johnny.conkin-1@nasa.gov
Aviation, Space, and Environmental Medicine
|July 17, 2013
Summary
This study developed a model to predict decompression sickness (DCS) probability using decompression dose, gender, and exercise intensity. Higher values in these factors increase DCS risk, with tissue ratio (TR) proving adequate for altitude exposures.
Area of Science:
- Aerospace Medicine
- Physiology
- Risk Assessment
Background:
- Probabilistic decompression sickness (DCS) models benefit from diverse DCS incidence data.
- The Air Force Research Laboratory Altitude Decompression Sickness Research Database provided data from 708 human altitude chamber exposures.
- Data included 340 DCS outcomes with incidence ranging from 0% to 88%.
Purpose of the Study:
- To develop a probabilistic model for DCS.
- To identify key predictors of DCS probability.
- To evaluate different measures of decompression dose.
Main Methods:
- Logistic regression and the Hill equation were employed.
- Decompression dose was defined using tissue ratio (TR) or bubble growth index (BGI).
- Gender and peak exercise intensity at altitude were included as predictors.
Main Results:
- Decompression dose, gender, and exercise intensity significantly contributed to the DCS probability model.
- Higher decompression dose (TR or BGI), male gender, and increased exercise intensity elevated the modeled DCS risk.
- TR and BGI yielded comparable results for predicting DCS.
Conclusions:
- A simple tissue ratio (TR) is sufficient for modeling DCS in straightforward altitude exposures.
- The developed model is heuristic and applicable to 4-hour exposures.
- Factors like gender and exercise intensity are crucial in DCS risk assessment.
Related Concept Videos
01:23Hypoxia
Hypoxia is a medical condition characterized by an inadequate oxygen supply to body tissues. It typically manifests as a bluish discoloration of the skin and mucosae, especially in fair-skinned individuals, when hemoglobin (Hb) saturation drops below 75%.
Types of Hypoxia
There are four primary types of hypoxia, each resulting from a different cause:
1. Anemic hypoxia: This type occurs due to insufficient oxygen delivery caused by a lack of red blood cells (RBCs) or RBCs with abnormal or...
Types of Hypoxia
There are four primary types of hypoxia, each resulting from a different cause:
1. Anemic hypoxia: This type occurs due to insufficient oxygen delivery caused by a lack of red blood cells (RBCs) or RBCs with abnormal or...
01:21Acute Respiratory Failure-II
Type I Respiratory Failure, or hypoxemic respiratory failure, occurs when the partial pressure of oxygen (PaO2) in arterial blood falls below 60 mmHg while breathing room air without a corresponding increase in arterial carbon dioxide levels (PaCO2). This condition highlights a significant impairment in the lungs' capacity to oxygenate the blood.
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
The underlying physiological abnormalities that contribute to hypoxemic respiratory failure include:
01:25Hyperpnea and Hyperventilation
Hyperventilation refers to a higher-than-normal rate and depth of breathing, often associated with anxiety attacks. This excessive breathing surpasses the body's need to expel CO2, leading to a condition known as hypocapnia - an unusually low level of carbon dioxide in the blood. Hypocapnia can constrict cerebral blood vessels, reducing blood flow to the brain, which may result in dizziness or fainting. Early signs include tingling and muscle spasms in the hands and face, caused by falling...
01:26Pneumothorax-I
A pneumothorax is a condition where air builds up in the space between the lung and the chest wall, causing the lung to collapse. This condition arises when air enters the space between the parietal and visceral pleura, disrupting the negative pressure essential for lung inflation. This can lead to a partial or complete collapse of the lung.
Pneumothorax can be even further classified as spontaneous, traumatic, and tension pneumothorax.
Pneumothorax can be even further classified as spontaneous, traumatic, and tension pneumothorax.
01:18Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...
01:08Pneumothorax II: Pathophysiology
Pneumothorax means the presence of air in the pleural space — the thin potential gap between the visceral and parietal pleura. This condition disrupts the normal pressure balance that keeps the lungs inflated, leading to partial or complete collapse of the affected lung.Normal physiologyUnder normal conditions, the pleural space maintains a slightly negative intrapleural pressure, which keeps the lungs expanded against the chest wall. This negative pressure creates a delicate balance between...