Research Projects

What’s Left to Learn about Bubbles?



EUBS 2017 has left us with more questions than answers, on the topic of post-dive bubbles.

Ballestra presented the preliminary results of an exploratory study of the effects of sonic vibrations on post-dive venous gas emboli detected by transthoracic echocardiography1. (more…)

Outcomes of Decompression Illness

Recompression treatment and hyperbaric oxygen (HBOT) are standard treatment for decompression illness. While it is generally accepted that sooner recompression is associated with better outcomes, the urgency of treatment may not be same for all cases. Looking for practical guidelines we regularly consult published case series. Three case series presented at EUBS 2017 may be used to illustrate problems with such approach. (more…)

What is the Common Risk Faced by Recreation, Technical, and Breath Hold Divers?

Immersion pulmonary edema (IPE) continues to be a central focus of dive medicine researchers and clinicians. Late last week, at the 2017 EUBS Annual Meeting, four scientists presented five different studies on the subject.

It appears that IPE is significantly more common than previously reported. In a two year period (2014-16) one hyperbaric facility in Cozumel diagnosed 40 cases of IPE among recreational scuba divers­1. On the other side of the world, there were 21 cases of IPE reported among French military rebreather divers in a six year period2. (more…)

Bubble Production in Divers Who Have Had DCS

Venous gas embolism (VGE), or bubbles, in divers postdive indicates that their decompression was too fast, their bodies became supersaturated and free gas emerged from solution in tissues. The occurrence of free gas is considered a necessary condition for decompression sickness (DCS), which can happen even without VGE. However, the presence of VGE increases the number and types of possible harms to the body and thus the probability of DCS.

A number of studies indicate variability in proneness to DCS among divers; however, the question of whether divers who have suffered DCS produce bubbles more readily in general has not been answered yet. To answer this question, researchers would need to identify “bubblers” and “nonbubblers” and observe the outcomes of their dives over some period of time, which would require a lot of resources and time.

Can Crystalline Salt Reduce the Size of Scuba Equipment?

safe diver quiz

A popular article over last few days is one about crystalline salt that can uptake and store oxygen in high concentration. It was published in Chemical Science by Jonas Sundberg and coauthors from University of Southern Denmark.1 The article describes a synthetized crystalline containing cobalt combined with an organic compound, which has some properties of biological carriers of oxygen like iron-based hemoglobin in mammals or similar copper-based carriers in other animals.

The most significant property of this crystalline is that it binds oxygen reversibly – it can uptake oxygen and release it – and that this process may be controlled.  Professor Christine McKenzie, the leader of the team that synthetized the crystalline, told the Science Daily2 that among other applications:  “When the material is saturated with oxygen, it can be compared to an oxygen tank containing pure oxygen under pressure – the difference is that this material can hold three times as much oxygen. This could be valuable for lung patients who today must carry heavy oxygen tanks with them. But also divers may one day be able to leave the oxygen tanks at home and instead get oxygen from this material as it “filters” and concentrates oxygen from surrounding air or water. A few grains contain enough oxygen for one breath, and as the material can absorb oxygen from the water around the diver and supply the diver with it, the diver will not need to bring more than these few grains.”

Oil Particulate and Carbon Dioxide in Divers’ Breathing Gas

At the ONR-NAVSEA Undersea Medicine Program Review that took place this summer in Durham, North Carolina, two presentations pertained to monitoring Navy divers’ breathing gas for oil particulate contamination and carbon dioxide (CO2) levels.

Contamination of breathing gas may cause adverse health effects in divers. The type of injury depends on the contaminant. Impaired judgment and loss of consciousness, both of which may be deadly underwater, are among the most severe symptoms associated with CO2 and oil particulate contamination. The U.S. Navy bases their breathing air standards on CGA G-7.1 Grade D criteria, which lists a safety standard of 5 mg/m3 for oil mist and particulate and a maximum of 1,000 parts per million for CO2. So far, there is no convenient means of monitoring breathing gas for these contaminants outside of specialized laboratories.


Using the Selfie as a Telemedical Tool

isolated hand holding smartphone or phone
Last April, a Canadian woman named Stacey Yepes experienced stroke symptoms, but by the time she made it to the hospital her symptoms were gone. Because her physicians could not find any signs of stroke, they believed that she was displaying symptoms of stress and released her home. A few days later, she had a similar attack and used her phone to tape herself during an episode in which she suffered from facial drooping and slurred speech. The video helped her doctors diagnose her with TIA (transient ischemic attack).

In many cases of diseases with transitory symptoms, physicians are unable to diagnose patients and opportunities for early treatments are missed. In the case of TIA, it is especially important to establish an early diagnosis and provide treatment to prevent the progression of symptoms and permanent loss of brain tissue. TIA can lead to blood clotting in the brain, but early administration of thrombolytic medication can prevent clotting and brain damage. Because of the transitory nature of TIA symptoms, some hospitals offer stroke telemedical consultations to enhance diagnosis of and establish early eligibility for thrombolytic medication. By using video connections, they establish a correct diagnosis in 96% of cases, as compared with only 83% of cases in which symptoms are only reported by phone.