Screening tools to detect lung, heart disease developed by two high school students

Two Michigan high school students, sisters Ilina and Medha Krishen, have developed screening tools using electronic stethoscopes to detect lung and heart disease. The sisters will present their findings at CHEST 2014 in Austin, Texas next week. Credit: The Krishen family

Two Michigan high school students, sisters Ilina and Medha Krishen, have developed screening tools using electronic stethoscopes to detect lung and heart disease. The sisters will present their findings at CHEST 2014 in Austin, Texas next week.

Ilina Krishen became aware of the dangers of smoking and chemical air pollution when she saw the effects of lung disease on family members. Curious to find a way to detect early lung damage in people exposed to noxious air pollutants, Ilina, a high school senior at Port Huron Northern High School in Michigan, developed a screening mechanism using an electronic stethoscope. An electronic stethoscope overcomes the problem of low sound levels by electronically amplifying body sounds, using an electromagnetic diaphragm that captures the diaphragm movement as an electrical signal.

Ilina recruited 16 smokers, 13 firefighters, and 25 nonsmokers for her test. The electronic stethoscope recorded one breath cycle from each volunteer. Frequency peaks were used to analyze the frequency distribution of breath sounds. Differences of peaks above 125 Hz were analyzed.

Ilina found that the number of peaks was significantly higher in smokers and firefighters, even if the firefighters were nonsmokers. She realized that although firefighters wear protective masks when fighting fires, they often do not wear masks when making a second check of the building after the fire is out. "The firefighters are exposed to many poisonous chemicals that remain in the air after the fire has gone out," said Ilina. "Screening with an electronic stethoscope may be able to detect early changes in lung function in individuals without symptoms of lung disease."

Medha Krishen, Ilina's sister and a junior at Port Huron Northern High School, also presented a study that used an electronic stethoscope to screen student athletes for hypertrophic cardiomyopathy (HCM).

Medha studied 13 individuals: 10 with a normal cardiac sports physical and three with a diagnosis for HCM. Heart sounds were recorded in 5-second periods while the athletes were lying down, standing, and after exercise. Frequency peaks of a frequency amplitude plot were analyzed. Studies showed a significant difference in the distribution of frequency peaks in the two groups between the lying down position and after exercise. Normal athletes showed a lower percentage of peaks above 131 Hz after exercise, while the athletes at risk showed a rise in frequency peaks following exercise.

"When I was in fifth grade, a family friend died after exercise, and I always wanted to learn more about how to prevent something like that happening," said Medha. "My study analyzing heart sound frequencies may be a useful technique that school staff could use to screen for HCM."

The sisters are both athletes -- Ilina is a varsity tennis player, and Medha is an accomplished figure skater -- and they take a personal interest in the health of athletes. They are also nonsmokers and hope to encourage others not to smoke. After Ilina completed her study and showed her study subjects the results of her tests "two or three of the smokers have quit smoking, and that makes me feel good," says Ilina.

Source: American College of Chest Physicians

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When you lose weight, where does the fat go? Most of the mass is breathed out as carbon dioxide, study shows

Despite a worldwide obsession with diets and fitness regimes, many health professionals cannot correctly answer the question of where body fat goes when people lose weight.
Credit: © Lovrencg / Fotolia

Despite a worldwide obsession with diets and fitness regimes, many health professionals cannot correctly answer the question of where body fat goes when people lose weight, a UNSW Australia study shows.

The most common misconception among doctors, dieticians and personal trainers is that the missing mass has been converted into energy or heat.

"There is surprising ignorance and confusion about the metabolic process of weight loss," says Professor Andrew Brown, head of the UNSW School of Biotechnology and Biomolecular Sciences.

"The correct answer is that most of the mass is breathed out as carbon dioxide. It goes into thin air," says the study's lead author, Ruben Meerman, a physicist and Australian TV science presenter.

In their paper, published in the British Medical Journal today, the authors show that losing 10 kilograms of fat requires 29 kilograms of oxygen to be inhaled and that this metabolic process produces 28 kilograms of carbon dioxide and 11 kilograms of water.

Mr Meerman became interested in the biochemistry of weight loss through personal experience.

"I lost 15 kilograms in 2013 and simply wanted to know where those kilograms were going. After a self-directed, crash course in biochemistry, I stumbled onto this amazing result," he says.

"With a worldwide obesity crisis occurring, we should all know the answer to the simple question of where the fat goes. The fact that almost nobody could answer it took me by surprise, but it was only when I showed Andrew my calculations that we both realised how poorly this topic is being taught."

The authors met when Mr Meerman interviewed Professor Brown in a story about the science of weight loss for the Catalyst science program on ABC TV in March this year.

"Ruben's novel approach to the biochemistry of weight loss was to trace every atom in the fat being lost and, as far as I am aware, his results are completely new to the field," says Professor Brown.

"He has also exposed a completely unexpected black hole in the understanding of weight loss amongst the general public and health professionals alike."

If you follow the atoms in 10 kilograms of fat as they are 'lost', 8.4 of those kilograms are exhaled as carbon dioxide through the lungs. The remaining 1.6 kilograms becomes water, which may be excreted in urine, faeces, sweat, breath, tears and other bodily fluids, the authors report.

"None of this is obvious to people because the carbon dioxide gas we exhale is invisible," says Mr Meerman.

More than 50 per cent of the 150 doctors, dieticians and personal trainers who were surveyed thought the fat was converted to energy or heat.

"This violates the Law of Conservation of Mass. We suspect this misconception is caused by the energy in/energy out mantra surrounding weight loss," says Mr Meerman.

Some respondents thought the metabolites of fat were excreted in faeces or converted to muscle.

"The misconceptions we have encountered reveal surprising unfamiliarity about basic aspects of how the human body works," the authors say.

One of the most frequently asked questions the authors have encountered is whether simply breathing more can cause weight loss. The answer is no. Breathing more than required by a person's metabolic rate leads to hyperventilation, which can result in dizziness, palpitations and loss of consciousness.

The second most frequently asked question is whether weight loss can cause global warming.

"This reveals troubling misconceptions about global warming which is caused by unlocking the ancient carbon atoms trapped underground in fossilised organisms. The carbon atoms human beings exhale are returning to the atmosphere after just a few months or years trapped in food that was made by a plant," says Mr Meerman, who also presents the science of climate change in high schools around Australia.

Mr Meerman and Professor Brown recommend that these basic concepts be included in secondary school curricula and university biochemistry courses to correct widespread misconceptions about weight loss among lay people and health professionals.

Source: University of New South Wales

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