Tag Archives: Medical

What would happen if air bubbles from a syringe are not removed?

The main risk with leaving an air bubble in a syringe is inaccurate dosing. With the syringe partly full of air, the amount of liquid won’t be accurate to the markings on the syringe.

Getting air into a vein isn’t a significant hazard unless it’s a huge amount – like a whole drip tube full or someone squeezes a drip bag in, including the large air bubble.

The air will circulate in the veins and reach the lungs where it will lodge and get removed in a few minutes. The lungs will filter out the air so it can’t travel to the brain except where there is also a “hole in the heart”.

How does breathing into a paper bag help hyperventilation?

Hyperventilation is the state in which the rate of alveolar ventilation of carbon dioxide is greater than the body’s normal production rate of the gas. It happens when one gets very excited or stressed. Sometimes, people also voluntarily hyperventilate, usually swimmers and yoga practitioners. Involuntary hyperventilation is triggered by a variety of reasons, including respiratory disorders, over physical activity, reduced air pressure and panic attacks.
One long-used technique to help with hyperventilation is breathing into a paper bag. Many doctors around the world have been suggesting this method to their patients for a long time. The paper bag has almost become a readymade solution for hyperventilating like bandage for wound.
The question is how breathing into a bag help with the rapid breathing. To understand that we have to know what happens when we hyperventilate and the mechanism of blood. The pH value determines the acidity of a fluid. A value of 7 in the pH scale means neutral. A value below 7 means acidic and higher than 7 indicates basic. The normal pH value for blood is 7.4, meaning it to be slightly basic.
When we hyperventilate, we take in more oxygen, and the blood gets more basic. The level of carbon dioxide in blood falls, a state known as hypocapnia. Carbon dioxide is carried by blood in the form of bicarbonates. To compensate the drop of carbon dioxide, the hydrogen ions in blood combine with the bicarbonates to free more carbon dioxide. This would result in the loss of hydrogen ions and further increase of alkaline nature of the blood. It is known as respiratory alkalosis. This leads to several problems like constricting of blood vessels and reduction in calcium levels in blood. People would feel dizziness, headache and seizures.
The idea behind breathing into a bag is re-breathing our exhaled carbon dioxide. When the carbon dioxide enters the bloodstream, it will balance the pH value.
Despite its widespread practice, the latest studies have come up with strong advice against the technique of breathing into the bag. The main reason for such a move was the ambiguity in the matter. Often the symptoms of asthma and heart attack get confused with those of hyperventilation. In those times, breathing into a bag can raise the level of carbon dioxide in blood and it could be deadly. There have been a number of such cases in the recent past. Many doctors are now recommending alternative breathing exercises or using an open tube instead. Those who rely on paper bag method are advised not to do it continuously.

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Why do doctors feel your testicles and ask you to cough in a physical?

Most of the guys would have encountered this embarrassing episode during a physical examination when the doctor touches their testicles and tells them to turn their head and have a cough. Despite how discomfiting the act seems, it is one of the important examinations doctors carry out. So, essentially what are they looking for when they do this? In the simplest terms, they are looking for hernia.
A hernia is a condition in which a part of an internal organ is displaced and squeezes through an opening or weak point of the cavity that contains it. There are different types of the condition; inguinal (inner groin), incisional (from an incision), femoral (outer groin), umbilical (belly button), and hiatal (upper stomach). When doctors ask you to turn to your side and cough, they are specifically looking for inguinal hernia, which is the most common among the various types, and mostly occur in men. It is estimated that around 66% people show the signs of inguinal hernia.
Inguinal hernias happen when lower intestine or the bladder starts to come through the lower abdominal wall through a small hole or into inguinal canal of the groin. The inguinal canal is situated where the testicles meet the upper torso. The natural weakness of men in this region is one of the prime reasons for the occurrence of inguinal hernia. The doctors have to put their fingers near the top of the testicles on a male patient and ask him to cough so that if a hernia is there, it can be sensed bulging from the lower abdomen. The patients are asked to turn their heads to direct the cough away from the physician. Some are only asked to cover their mouth with their hands. The act of coughing can help the doctor easily discern the presence of hernia, since the bowel is pushed downwards while coughing.
The hernias are caused by weakness or opening in walls of the muscles and the pressure of the organ. The pressure pushes the organ through the opening or towards the soft part of the muscle creating a bulge on the walls of them. People may have the weakness in muscles at birth or may develop it later, mainly through the activities that exert unusual pressure on the internal organs. According to researchers, 27% men and 3% women develop hernia at some point of their lives. Surgery is the most recommended treatment for hernia, although minor problems can be solved with watchful observation. The surgery for hernia is commonly called hernia repair.

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What is the history behind the invention of hypodermic syringe?

Even the most mentally strong people can be found wary when the words syringe and injection are mentioned before them. Most people have developed an uncharacteristic fear for injection. There is even a word for it: trypanophobia. They like to take bitter medicine than suffer the pain of injection. In fact, syringe is a great help. The medicine we swallow take some time to reach the stomach and then enter the blood and then to reach the intended organ. But often, the medicine must be applied urgently and that is where the need of syringe comes. The syringes have a hollow needle at the tip of medicine tube, which can pierce the skin. Through this needle, fluids can be injected into the body and bodily fluids can be extracted as well.
The practice of injecting medicines into body has a long history. The concept of injection had taken root in as early as second century AD. The controversial doctor Galen used to inject medicine directly into brain of the patients. From 17th century, various scientists had indulged in experiments of syringes. During his experiments on the circulatory system, William Harvey used to inject various colors into blood vessels. All these injection systems had a major drawback. These could be applied only through a natural opening or a wound on the body. The doctors used to make small cuts on the body for injections which was a dangerous practice.
In 1844, Irish doctor Francis Rynd made a hollow needle, which changed the history of syringes. He claimed to have injected drugs into a woman using his invention. A few years later, a French doctor named Charles Gabriel Pravaz entered with his own hypodermic syringe. Hypodermic means anything beneath the skin. Actually it was coined in 1858 only, by Dr. Charles Hunter. Pravaz’s hollow needle, made of silver, was 3 cm long and of 5 mm in diameter. The doctor had only to push the piston to inject the medicine into body once the needle was inside the body. If the piston was drawn back, the blood could be collected in the syringe. Pravaz’s achievement was in 1853. Around the same time, a Scottish doctor named Alexander Wood also invented an identical syringe. It was Wood who made the syringe popular over the world. He used it to inject drugs into patients and himself and eventually became an addict of morphine along with his wife.
The syringe underwent various innovations in later years and in 1949, an Australian inventor named Charles Rothauser developed the world’s first disposable hypodermic syringe. In 1956, Colin Murdoch from New Zealand made the first fully disposable plastic syringe as well. Today there are billions of users of the contraption.

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What are stem cells? What are their uses?

The stem cell preservation is one of the medical fields that witness a large number of researches nowadays. Stem cells are a kind of undifferentiated cells found in the body of multicellular organisms. Also known as root cells, they can develop by new stem cells through mitosis and also differentiate into other types of cells. The new stem cells developed through mitosis will have the same characteristics of their parents. They can continue as stem cells or can convert into a different type of cell as well.
The word stem cell was coined by Russian scientist Alexander Maksimov in 1908. It was in 1981 when the scientists extracted the stem cells for the first time. The embryonic stem cells were derived by Martin Evans, Matthew Kaufman and Gail R. Martin from mouse. Then in 1998, the first human stem cells were extracted as well.
The stem cells don’t have definite shape or structure. They show great ability for differentiation even after a long period of time. There are two kinds of stem cells; Embryonic stem cells and Adult stem cells. The embryonic cells are developed from blastocysts about 4-5 days old. They are then grown through special medium and subjected to various experiments. This mode of growing cells in labs is called cell culture. Apart from this, the embryonic cells can be also taken from the umbilical cord blood just after the childbirth. The adult stem cells are found in the grown organs or tissues. They are also called somatic stem cells. The major sources of adult stem cells are adipose tissues, blood and bone marrow. Recently, the scientists have also discovered that it is possible to extract stem cells from teeth.

Image Source: TIME Magazine (Click to view in full size)

Since new cells can be derived from stem cells, they have made a huge impact in medicine. With the help of stem cells, cure be developed for all diseases triggered by the damaging of cells. This is called stem cell therapy. The stem cells work by repairing damaged part of the body.
It has been proved that the stem cell therapy is useful for many diseases like cancer, lung diseases, liver degeneration, Parkinson’s disease, multiple sclerosis, cerebral hemorrhage, Alzheimer’s disease and diabetes. On the basis of their use, stem cells can be divided into three main types; Totipotent cells which can turn into any type, Pluripotent which can turn any type except placenta and Multipotent which can turn only to some types.
In 2010, the scientists of Wake Forest University, London grew a liver from stem cells. Two years later a group of scientists from Gothenburg University of Sweden developed a vein as well. British scientist John Gordon and Japanese scientist Shimna Yamanaka shared the 2012 Physiology Nobel Prize for converting ordinary cells to stem cells.
Like blood donation, stem cells can also be donated. Many hospitals and laboratories have now facilities to store stem cells. Usually people between 18 and 35 are allowed to donate stem cells.
Additional reading:
Stem cell (Wikipedia)

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Who is the inventor of band-aid that is used to cover wounds?

Founded during the year 1886, American company Johnson & Johnson was making surgical dressing materials for hospitals at the time. These did not include band-aid which is stuck on wounds; nor was the company doing research in that direction.

Band-aid was invented by one of the employees of the company, named Earle Dickson, almost by accident. Meaning, it randomly occurred to him to invent band-aid. It so happened that Dickson’s wife Josephine would often get wounded doing household chores and every time Dickson would have to cover the wound with cotton bandage that would loosen and fall off in some time. Assuming that this situation could be improved with sticking plaster, Dickson took a thick cloth, smeared an adhesive named crinoline on it and stuck plastic covering to it. Then cut it in shape of stripe and started using it for his wife’s wounds. This was convenient as whenever his wife got a wound, he would cut the rolled bandage in stripe and use it on the wound, and it would stay stuck on the wound for days.
Johnson & Johnson bought rights of Earle Dickson’s invention. Instead of a roll of bandage they started marketing it in the form of spare stripes in 1924 and named the product band-aid. At first it did sell much, but gradually it earned popularity around the world.

How does an artificial heart work? Who was the first recipient?

Barney Clark

The world’s first successful mechanical heart began beating in a human chest in December 1982. The recipient was Barney Clark (photo, left), a 61-year-old dentist, whose own heart was pumping just one-fifth of the blood that it should. As Clark’s heart began to beat irregularly, physicians decided it was time to try the Jarvik-7 mechanical heart, which had been tested only on animals.

The Jarvik-7 (picture, below) is a plastic pump that fits inside the patient’s chest. The heart is powered with compressed air supplied by hoses that pass through the patient’s chest. Surgeons made a history as they cut away the exhausted ventricles of Barney Clark’s heart. The Jarvik-7 was then attached directly to the remaining upper chambers of Clark’s natural heart. Air hoses were passed under the rib cage and connected to the external pump. The artificial ventricles pumped blood to the lungs and out into the body. After a 7-hour operation, Barney Clark awoke to the rhythmic click of the first artificial heart implanted in a human.
Jarvik-7
Clark and his physicians were ecstatic, but soon the disadvantages of the mechanical heart became obvious. Clark never could move far from the 170-kilogram equipment that powered and controlled his heart. The air tubes inserted into his chest exposed his body to the constant risk of infection. Soon he began to suffer from kidney failure. The mechanical heart battered his blood so badly that regular transfusions were required. Doctors admitted that the mechanical heart was a temporary solution. However, when Barney Clark died after 112 days on the mechanical heart, doctors hailed him as a medical pioneer.

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What is bionic technology or bionics?

Bionic technology or simply bionics is one of the newest branches of science and a wonderful amalgam of electronics, robotics and human psychology. It is so modern that even the recent editions of the leading dictionaries explain the meaning of the word ‘bionic’ as a fictional character having artificial body parts and capable of doing things which no average human being can do! On the other side, the practical of ‘putting on’ artificial limbs to make up for the missing original limbs is centuries old. But the erstwhile ‘technology’ which provided such artificial limbs, and still provides in most of the cases, bears no relationship with the bionic technology which appears futuristic in comparison. As a matter of fact, both the technologies happen to be poles apart.
Bionic Technology
Under the traditional method, a wooden leg or a marble or glass eye was made for a person who had lost a leg or an eye. Making well-fitting limbs certainly called for craftsmanship but no technology was involved. Such prostheses (artificial limbs) served no purpose other than giving some support to the wearer’s body or making him feel that he appeared physically quite normal to the people who saw him.

Bionic technology does not stop at making well-fitting prostheses. The tern ‘bio’ in the word bionic has not been prefixed for nothing. The fundamental agenda of bionic technology is to ensure that artificial limbs such as eye, leg or arm carry out their functions like the normal limbs. In short, even if the limb fitted in the place of the missing one happens to be a non-living thing, it must be sufficiently ‘live’ to carry out its functions according to the desire of the wearer.

This was a great challenge. Hence the researchers had avoided grappling with it till the end of the 20th century. Instead, they had experimented with two comparatively easy options and were rewarded with correspondingly low rate of success. The first of these options was the removal of the non-functioning limb or the organ surgically and transplanting a healthy, functioning body part in its place. Another option was that of avoiding surgery altogether and getting the work of the diseased or non-functioning organ done through a machine.

Successful experiment of the option no. 1 was carried out for the first time on a young man named Joseph Murray in Boston city of the USA in 1954 when the surgeons transplanted one of his diseased kidneys with the healthy kidney donated by his twin brother. Other major milestones in the field of human organ replacement were transplantation of liver and that of heart in 1976. As regards the option of entrusting the work of the malfunctioning organ to a machine, the first breakthrough came in the form of artificial kidney or kidney dialysis machine invented by the German researcher Willem Kolb in 1943. However, it did not become harbinger of other similar machines for the simple reason that other machines of continuous requirement had to be very small in size so that they could be fitted inside the body, not to mention the problem of ensuring power supply for them. The experiments regarding implanting artificial heart were taken up during the decade of 1980s but they were not considered successful as all they could achieve was the postponement of the patient’s death by a few months.

It should be remembered that all these efforts had been aimed at only four or five organs while nothing much could be done for other limbs and organs. The main stumbling block faced by the researchers so far had been the inability to make the artificial organ adapt to the biology of the patient. A perfect synthesis of engineering and electronics was called for in order to tackle this problem. The last decade of 20th century was spent by the researchers in establishing the required fine-tuning. It is only now, in the first and the second decade of the 21st century that the experts in these diverse fields have started tasting success up to some extent and have opened up the novel field of bionic technology.

The research on giving a complete bionic form to many human limbs is on fast track. In other words, the research on making of bionic man is in full swing, albeit the bionic revolution is yet to achieve full bloom.

Additional reading:
Bionics (Wikipedia)

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What is chloroform? Why does it send the person to sleep?

All our consciousness depends upon work done by the brain. When we think, our brain is at work. Or when we see, or when we feel pain, our brain is working. A person who has breathed a sufficient quantity of chloroform or ether, or who has had a large enough dose of opium or alcohol, can not feel pain even when the skin is cut, because pain is really felt in the brain, and the brain of such a person is prevented from working.

The question, then, is: How do anesthetics, as these things are called, stop the working of the brain? Such an anesthetic as chloroform is made up of certain chemical molecules. When chloroform is breathed these molecules pass into the substance of the brain itself. There the chloroform molecules combine with the molecules of the brain, probably with the result that the brain can no longer use up the oxygen in the blood, and so has to stop working. But as soon as the person stops breathing chloroform his blood going to the brain becomes free of it. The chloroform then passes back from his brain into the blood, and is breathed away by the lungs, going back the same way it came, and the person becomes conscious again.

The effect chloroform generally lasts about 1 to 2 hours, but it really depends on the individual as well as on the dosage.

Additional reading:
Chloroform (Wikipedia)

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Why some diseases are infectious while others are not?

Infection is due to the presence of a vast number of very tiny living cells called germs, or microbes, or bacteria. These little creatures are so small that it requires very high magnifying powers in a microscope to see them, but it is by their action on the living tissues of plants and animals that many diseases are produced. These germs are so small, and so light, that they can be carried about in the air breathed out from our lungs, so that they may contaminate the atmosphere or our food, and so spread disease wherever they go. That is what is meant by carrying infection. Thus the germs which cause typhoid fever or diphtheria often get into a milk supply or a water supply, and so cause an epidemic amongst all the people who use that source of water or milk.

There are many diseases which are not infectious, because they are not caused by these germs. For instance, many diseases are due to various forms of violence and pressure. This may be caused by lack of blood, or by blood being stopped from circulating properly. Still other diseases are due to various chemical substances which act as poisons upon the tissues of the body, while others are the results of extremes of heat and cold. But all these concern only the individual to which they apply at the time, and are not capable of being transmitted to somebody else, as are the diseases caused by bacteria.

More reading:
Infectious disease (Wikipedia)

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