Nav: Home

Predicting how bad the bends will be

March 15, 2017

DURHAM, N.C. -- Researchers have created a new model for predicting decompression sickness after deep-sea dives that not only estimates the risk, but how severe the symptoms are likely to be.

The US Navy Diving Manual may incorporate the model into its next update, as will commercial products intended to help recreational divers plan their ascents to avoid "the bends."

The results appear online on March 15, 2017, in the journal PLOS ONE.

"The current guidelines only give you a probability as to whether or not decompression sickness is likely to happen after a given dive," said Laurens Howle, professor of mechanical engineering and materials science at Duke, who has been working on these models with the Navy for a decade. "This is the first time we've been able to also address the likely severity of the potential sickness, helping divers determine acceptable risk."

All risks have two components -- the likelihood of something bad happening and just how bad that something is likely to be. Having a model that accurately provides both aspects will allow divers to better plan safe depths and ascents to help their bodies adjust -- preventing painful and potentially fatal results.

Decompression sickness occurs when dissolved gasses such as nitrogen and helium come out of solution inside the body, forming dangerous, painful bubbles. This happens when divers ascend too quickly, and the pressure of gasses within various tissues exceeds that of the surrounding pressure.

"Getting the bends is not fun," said Greg Murphy, a doctoral candidate in Howle's laboratory, who has experienced the full severity spectrum of decompression sickness firsthand. "While I was diving in a salvage zone for the Navy, my anchor broke and I shot to the surface. On the ride to the hospital, I could barely breathe even with pure oxygen."

No divers had to take such risks to gather data for the new model, as the Navy has a dataset of more than 3,000 simulated dives conducted in a carefully controlled hyperbaric chamber. Using that data, along with models of how gasses are absorbed and released by human tissue, Howle crunched the numbers to sort dives into six levels of potential severity.

Howle then divided the categories into a mild manifestation grouping (pain only) and a serious manifestation grouping (likely neurological or cardiopulmonary symptoms). He then assigned the same levels of acceptable risk currently used by the Navy to each. With a slight tweak to the definition of mild decompression sickness, the resulting model and boundaries of acceptable risk closely matched the practices already in place in the Navy, making it a useful predictive tool moving forward.

"Now that we have this model, we can use it to quickly and accurately predict the likelihood and severity of decompression sickness simultaneously to make decisions," said Howle. "We're also working to optimize the algorithm so that it could operate on a diver-worn computer so adjustments and new predictions could be made on the fly."
-end-
This work was supported by Naval Sea Systems Command (N61331-06-C-0014, N00024-13-C-4104).

CITATION: "The Probability and Severity of Decompression Sickness," Laurens E. Howle, Paul W. Weber, Ethan Hada, Richard D. Vann, Petar J. Denoble. PLOS ONE, March, 15, 2017. DOI: 10.1371/journal.pone.0172665

Duke University

Related Human Tissue Articles:

Scientists ID human protein essential for human cytomegalovirus replication
Scientists have demonstrated that a human protein known as valosin containing protein (VCP) is essential for replication of human cytomegalovirus (HCMV).
NASA, ASU collaboration develops 3-D tissue culture models to mimic human gut infections
An ASU Biodesign Institute team has reported their latest advancement in 3-D intestinal model development.
Scientists tissue-engineer part of human stomach in laboratory
Scientists report in Nature using pluripotent stem cells to generate human stomach tissues in a Petri dish that produce acid and digestive enzymes.
Scientists tissue engineer human intestines and functioning nerves
Scientists report in Nature Medicine using human pluripotent stem cells to grow human intestinal tissues that have functioning nerves in a laboratory, and then using these to recreate and study a severe intestinal nerve disorder called Hirschsprung's disease.
Scientists develop tissue-engineered model of human lung and trachea
Scientists at Children's Hospital Los Angeles have developed a tissue-engineered model of lung and trachea which contains the diverse cell types present in the human respiratory tract.
Functional human tissue-engineered liver generated from stem and progenitor cells
A research team led by investigators at The Saban Research Institute of Children's Hospital Los Angeles has generated functional human and mouse tissue-engineered liver from adult stem and progenitor cells.
Vanderbilt, human vaccines project launch studies to decode human immune system
Researchers at Vanderbilt University Medical Center this month began recruiting volunteers to participate in a clinical trial aimed at decoding the human 'immunome,' the genetic underpinnings of the immune system.
Pituitary tissue grown from human stem cells releases hormones in rats
Researchers have successfully used human stem cells to generate functional pituitary tissue that secretes hormones important for the body's stress response as well as for its growth and reproductive functions.
Engineered hydrogel scaffolds enable growth of functioning human breast tissue
Whitehead Institute researchers have created a hydrogel scaffold that replicates the environment found within the human breast.
New appreciation for human microbiome leads to greater understanding of human health
University of Oklahoma anthropologists are studying the ancient and modern human microbiome and the role it plays in human health and disease.

Related Human Tissue Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Bias And Perception
How does bias distort our thinking, our listening, our beliefs... and even our search results? How can we fight it? This hour, TED speakers explore ideas about the unconscious biases that shape us. Guests include writer and broadcaster Yassmin Abdel-Magied, climatologist J. Marshall Shepherd, journalist Andreas Ekström, and experimental psychologist Tony Salvador.
Now Playing: Science for the People

#513 Dinosaur Tails
This week: dinosaurs! We're discussing dinosaur tails, bipedalism, paleontology public outreach, dinosaur MOOCs, and other neat dinosaur related things with Dr. Scott Persons from the University of Alberta, who is also the author of the book "Dinosaurs of the Alberta Badlands".