At the current juncture, electronic cigarettes, or e-cigs, are not nationally regulated as a tobacco and help contribute to lung diseases such as emphysema and chronic obstructive pulmonary disease (COPD), the third leading cause of death nationwide. Additionally, smoking is the leading preventable cause of death in the world. So, if the problem is so large, why have e-cigarettes not yet been regulated nation-wide?
The Food and Drug Administration (FDA) has recently proposed polices that would include e-cigs as tobacco products and specifically include them in the Family Smoking Prevention and Tobacco Control Act that was signed into law by President Obama. The FDA is still aiming to extend other tobacco laws to include e-cigs, since the FDA oversight was limited to solely include cigarettes.
Because the decision to create nationwide regulations has already taken nearly a year to rule on, some “state and local jurisdictions have stepped in to pass laws and policies within their authority.” These policies include minimum age of purchase laws, location limitations of where e-cigs can be used (much like those of traditional cigarettes), and the additional taxes for the purchase of e-cigs and the associated accessories.
While these policies can be useful as a temporary fix, state laws can change often and quickly so the FDA will need to move quickly in order to create “rules and regulations that will achieve the greatest population health benefit and result in the beginning of the end of smoking as we know it.”
Have you ever heard of organ-on-a-chip? If you haven’t, you may soon. Researchers at Wyss Institute for Biologically Inspired Engineering at Harvard University recently developed a model of the human small airway to help study lung inflammatory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), outside of the body.
This development will help to “gain new insights into the disease mechanisms, identify novel biomarkers, and test new drug candidates”, without the invasiveness and costs associated with surgery. Additionally, the researchers also created a “microfluidic model of the lung small airway that recapitulates critical features of asthma and COPD”, which gives the team “a window on molecular-scale activities in the context of living human lung tissue.”
The team also noted that the organ-on-a-chip can be utilized as a discovery platform for disease-specific drugs and biomarkers. This means that “drugs targeting different key molecular components of inflammatory pathways can potently suppress pathological processes in asthma and COPD-tailored small airway chips.”
The organ-on-a-chip technology is helping to not only map out how COPD affects the human body, but how personalized treatments can be identified and created to help improve quality of life.
Here is a personal checklist that will enable you to determine whether you should consult your physician.
Does COPD run in my family?
Do I smoke?
Am I short of breath more than others?
Do I cough?
When I cough, do I cough up yellow or green mucus?
A careful history, with a focus on cough, expectoration, shortness of breath, wheeze, and the duration of these symptoms is basic. A careful smoking history and an occupational history detailing possible dust and/or irritant exposures are also needed. Most patients have had some telltale symptoms for years before they come to a doctor for an evaluation. None of these symptoms is specific or diagnostic by itself. A careful family history in reference to close relatives with COPD is important because COPD runs in families. Some common questions often asked by doctors or nurses to help evaluate the patient are listed in Tables 1 and 2. It is important to talk about the patient’s duration of symptoms, lifestyle, work environment, and problems related to the illness.
A complete physical examination should be performed during your first visit to a doctor.
Table 1: Questions a doctor may ask:
How long have you had cough, shortness of breath, or wheeze?
Have you seen many doctors for it? What are you now doing to treat it?
How many days did you miss from work last year because of the lung problem?
Were you in the hospital for it? How long and how many times last year?
Describe your usual good day.
Do you have more good days than bad days in a week? What are you able to do when you are feeling your very best?
Who do you live with?
What recreation do you prefer?
Table 2: More Questions Your Doctor or Nurse May Ask:
How does the emphysema or chronic bronchitis bother you?
When does it bother you the most?
What have you learned to do that helps you to live with it?
Does it ever embarrass you to have lung trouble?
Your physician will thoroughly examine your chest, observe your breathing patterns, and perhaps monitor how hard you are working to breathe. He or she will note the degree of over-inflation by percussion (tapping over the lungs). He will listen to your chest with a stethoscope to hear the air flow in and out of your lungs. The intensity (loudness) of the sounds is helpful. Noises caused by mucus or inflammation are also noted.
The physician or nurse will also listen to your heart sounds to determine the rate and rhythm of your heart and any signs of heart strain that may accompany advanced stages of COPD. The examination itself is not very accurate in determining the severity of the abnormality, however. A physical examination may be normal even in the early stages of significant disease. This is because airflow abnormalities are usually moderately advanced before they can be detected with a stethoscope!
Chest x-rays are not very useful in assessing the patient with COPD. By the time the x-ray is clearly indicative of the disease, the neighbors usually know the diagnosis! However, the x-ray may show over-inflation of the lungs, which is common in emphysema. X-rays are also valuable in finding other abnormalities such as shadows which may indicate coexisting lung cancer. Lung cancer and COPD often occur together because both are caused by smoking. The heart and the large vessels to and from the heart can also be seen on a chest x-ray and give some indication about associated heart strain, but only in advanced stages of disease. However, the chest x-ray can be completely normal, even when the patient has a significant degree of COPD. The x-ray, though traditional, is not a good way of diagnosing or evaluating COPD.
The EKG also is not useful in evaluating patients with COPD. In very advanced disease, EKG abnormalities are usually evidence of strain in the right side of the heart, i.e., that portion of the pump that propels blood from the tissue back through the lungs to take on oxygen and get rid of carbon dioxide.
Culturing the sputum of patients with emphysema and/or chronic bronchitis is almost useless. The common bacteria are well-known, and today physicians properly prescribe antibiotics based on their knowledge of the most common organisms and will do so if sputum increases in volume and becomes colored. Yellow or greenish sputum is almost always infected and requires antibiotics.
Measuring Lung Capacity
A simple device called a spirometer measures your lung capacity. During this test you take a deep breath, as deeply as you can, and blow it out all at once into a machine that records airflow and capacity. The total amount of air blown out of fully inflated lungs is called the vital capacity. Since the air is forced out by your muscular effort, it is called forced vital capacity (FVC, newer term FEV6). This test measures the useful size of your lungs. The rate of airflow tells how open the air passages are and how well the lungs can empty, or how well their elasticity is functioning. The lungs empty somewhat like an inflated balloon. Remember how a flabby or overused balloon empties slowly and incompletely? This is a lot like the lung with emphysema. The airflow test is called the forced expiratory volume in one second, since this airflow is timed or measured over the first second of exhalation. The symbol for forced expiratory volume in one second is FEV1. These two tests, the FVC and FEV1, reveal all your doctor needs to know about your lung capacity and airflow. These two numbers are somewhat similar to systolic and diastolic numbers in blood pressure readings. We believe that knowledge of FVC and FEV1 is as valuable and important to health promotion as knowledge of blood pressure. These tests measure your lung power, which is essential to your continuation and enjoyment of life.
Normal values are based on age, sex, and height. Younger and taller individuals have greater airflow and air volume than shorter or older people. Men have slightly greater airflow and air volume compared with women of the same age and height.
Self-Testing- Try It Yourself
Normal lungs have large volume, and they empty quickly because airways are open and lungs are elastic. You can do a little checking yourself with a stopwatch. Take a full breath; hold if for one second. Then, with your mouth open, blow out as hard and fast as you can. Your lungs should be completely emptied – meaning that you can blow no more air out even though you try– in no more than 4 to 6 seconds.
If one takes longer to blow out all the air, it means that airflow is obstructed or limited. Today we use the term “limited” because this airflow reduction can be due to either a loss of lung elasticity (emphysema) or problems with airways (asthmatic or chronic bronchitis). See how simple it is!
Unfortunately, routine lung function tests have been accepted all too slowly. No person would go for a complete check-up if the physician did not examine the eyes, ears, nose, throat, listen to the heart and lungs, feel the abdomen for any abnormal masses, and examine the genital, rectal, and pelvic areas. All these are routine, and to supplement them, appropriate laboratory blood and urine tests are done, plus an electrocardiogram and, usually, a chest x-ray. Unfortunately, none of these examinations or tests identifies early COPD.
Only spirometric measurements of the kind we have just described can identify the patient who is just beginning to develop a lung abnormality.
When one considers that the disease process finally resulting in disability may go on for 20 to 30 years, doesn’t it make sense to identify the problem early and to take immediate corrective action? The answer must be yes if you are to a enjoy a long happy life.
Very simple devices for measuring lung capacity are becoming popular. One such device is called a peak flow meter, which measures the greatest airflow rate you can produce. A man’s normal figure is around 600 liters per minute, and a woman’s is 370 liters per minute. Both are normal. (The lower value for women is because of their shorter stature and female sex). Some physicians instruct their patients to use peak flow meters at home to study the response to treatments designed to open up their air passages. Another new device called a spirometer accurately measures forced vital capacity. These measurements of both volume capacity (forced vital capacity) and flow can give a good estimate of the mechanical function of the lungs. (Newer, less expensive pulmonary function testing equipment is now readily available for use in primary care physician offices).
Other tests are used in more advanced stages of disease to obtain additional knowledge about the lungs’ function. One such test is the blood gas measurement. A small amount of blood is drawn from an artery by a small needle and syringe. This blood is analyzed to measure the amount of oxygen and carbon dioxide it contains. This test is used to assess more advanced stages of emphysema and chronic bronchitis and is needed when the physician is considering prescribing oxygen and in cases of serious and emergency illness.
Another simple method of measuring blood oxygen is with an instrument called an oximeter which is widely used today. It is popular because it does not require arterial blood sampling. However, it is not as accurate as arterial blood measurement, and it tells nothing about the levels of carbon dioxide or acid (pH) in the blood. The pulse oximeter measures blood oxygen by reflected light. This test is easy and painless and will be much more widely used in the future.
Additional lung function tests such as the diffusion test also measure the integrity of the air-blood interface, or alveolar capillary membrane. Numerous additional tests are used for research purposes, but they do not have any practical value at the present time.
In summary, adequate evaluation of patients with all stages of COPD is within the reach of all doctors and their patients. The approach is simple and straightforward. All patients with shortness of breath, cough, wheeze – particularly those with family history of COPD and absolutely all smokers – should insist on this crucial evaluation.
Answers from Dr. Thomas Petty, Professor of Medicine, University of Colorado.
Probably just about everyone who reads this monthly Newsletter knows about prednisone. Prednisone is in a class of drugs called corticosteroids, related to the cortisone group of medications. These drugs are highly useful in the management of asthma and some patients with COPD, and, quite frankly, I couldn’t get along without them in my practice. This statement has to be tempered with the clear understanding of what I call the “downside” of these valuable drugs, and these can be substantial. Yet many of the side effects can be avoided or minimized with certain strategies.
Prednisone is an anti-inflammatory drug and thus deals with inflammation of the conducting air passages in the lung. Inflammation may be present in both asthma and COPD. The strategic use of prednisone can soothe and thus heal the delicate lining layer of these passageways, making them more resistant to bronchospasm. Prednisone has another effect in preserving or even increasing the receptors for inhaled bronchodilators. Thus prednisone is used both to combat inflammation and to enhance the effectiveness of one of the most valuable bronchodilators we have for asthma and COPD. The downside is well-known. It causes wear and tear on the bones, and in some patients the acceleration of cataract formation and the worsening of glaucoma (high pressure in the eyes). The bone problem is much worse in women than men, and it is a particular problem in small-boned, light-skinned women beyond the menopause. On the other hand, large-boned, dark-skinned people have relatively little trouble with prednisone. Men have far less trouble than women, probably because their bones are larger to start with. The bone problem (osteoporosis) can be largely prevented by the appropriate use of calcium. A quart of skim milk gives 1,000 mg of calcium, and simple medications such as Tums contain a lot of calcium. Physicians believe that between 1,000-1,500 mg per day is necessary to help prevent osteoporosis. Exercise also helps protect the bones, and, of course, being able to breathe makes this exercise possible. (Newer medications have become available to help treat osteoporosis).
Anybody receiving long-term prednisone should have an annual eye exam and, of course, plenty of people have cataracts and glaucoma without the use of steroids. If steroids are making things worse, that fact can be dealt with by using medications and surgery. Short courses of prednisone cause almost no harm, and even low maintenance doses given each morning or evening in a single daily dose have minimal side effects in most patients. Most of the other rumors about prednisone are blown way out of proportion, but it is true that some folks have more trouble from prednisone than others. It’s hard to discuss all of the ins and outs of prednisone therapy in one short Newsletter, but the “bottom line” is prednisone is very useful in many patients and usually does a lot more good than harm. I’ll be in touch with you next month with more information on prednisone and some additional tips which may be interest.
(NOTE: Prednisone can also have an effect on blood sugar levels, which may be of importance to diabetics).
Dr. Thomas Petty, Professor of Medicine University of Colorado Health Sciences Center; Consultant and Faculty at HealthONE Center Denver, CO.
Almost everyone knows of the harmful effects of tobacco smoke. It has been conservatively estimated that regular smokers of cigarettes sacrifice seven years of life. If one divides the number of cigarettes smoked in a lifetime on the average into this seven years loss, it turns out to be 5 ½ minutes for each cigarette! What an astonishing statistic. The premature loss of life is primarily due to doubling the risk of heart attack, lung cancer, and emphysema. There are other cancers such as bladder, larynx, esophagus, pancreas, and uterus which are also caused by tobacco. Thus, it becomes pretty clear that stopping smoking is critical to future health. Never starting, of course, is better.
"But I have already smoked too long, doctor" is a common statement of my patients. “It won’t do me any good now because too much damage is already done,” they will continue. Nothing could be further from the truth. It is now known that there is benefit from stopping smoking no matter how long you have smoked. The risk of heart attack returns to normal after five years of non-smoking, and cancer risk goes way down also after five years or more of smoking cessation. In emphysema, the rate of loss of breathing capacity slows once people finally stop. Even patients over the age of 60 with advanced degrees of impairment live longer if they stop smoking. Thus, it is pretty obvious that no one should continue to smoke no matter what their preconceived notions about damage already done may be.
But how to stop—-ah-h-h—that’s the question! There is no simple answer. A personal commitment to quitting is, of course, fundamental. Setting a date for stopping, substitution with candies, chewing gum or something else to chew on helps a bit. Nicotine containing gum is useful in many patients in dealing with the withdrawal symptoms which plague many nicotine addicts. Nicotine patches and nasal spray are also effective. The changing of life patterns and avoiding social signals which call for a cigarette is also extremely helpful. There is no way that I can tell everyone who reads this newsletter exactly how to stop smoking, but in fact, nearly everyone can stop now. It is not really later than you think. Plan for your first no smoking day in a long time soon because, after all, "it is the first day of the rest of your life."
Thomas L. Petty, M.D., Professor of Medicine, University of Colorado.
As a clinician and clinical scientist, and one who likes to speak to public groups, I am often asked the question, which is the title of this month’s newsletter. Yes, friends, there will be cures to most diseases, but let’s limit the discussion to the common problem of pulmonary disease.
Asthma is a problem for both the young and old, and it can be mild or severe. Air passages are obstructed with asthma both intermittently and chronically. New developments and understanding of basic asthma mechanism are being reported almost daily. The discovery of these mechanisms leads to new drugs and treatment strategies, which are equally important. Today, we recognize asthma as having two major factors, i.e., a bronchospastic factor when there is a sudden muscular narrowing of air passages, and an inflammatory factor which also narrows the air passages and creates mucus. A growing number of potent bronchodilators can open up air passages by relaxing these airway muscles. Today, there is more focus on methods of preventing or treating inflammation. In more pure forms of asthma, a drug Cromolyn (Intal) is an excellent preventative for many people. It is useful in both children and adults. It doesn’t do anything for established inflammation, however. Active inflammation requires our old “friends,” the corticosteroids, namely prednisone. In other newsletters, I have pointed out that prednisone is much more of a friend than a foe. It can be used strategically to combat active inflammation. Some individuals also require prednisone on a regular basis to prevent the progress of the disease. Inhaled corticosteroids, i.e., beclomethasone, bedenoside, flunisolide, fluticasone, triamcinolone, may also be effective in some patients with COPD, but mostly these are patients who primarily suffer from asthma. Additional drugs that are not related to the cortisone family are under study, and I am sure that within a number of years we will have alternate approaches to the problem of inflammation in bronchial asthma.
COPD is more persistent and progressive form of airflow obstruction and includes Asthmatic Bronchitis, Chronic Bronchitis, and Emphysema. Stopping smoking is the answer to prevention and progression of COPD. By stopping all smoking, the great majority of patients could avoid COPD altogether or could stop it in its tracks. Those patients with the rare form of congenital alpha 1 antitrypsin deficiency can now have a replacement therapy. The alpha antiproteinase is called prolastin. It requires weekly or possibly only monthly infusions. In effect, it is a cure because it replaces the basic deficiency. But, it is not for all forms of COPD. (Two other forms of treatment for alpha 1 deficiency have just been introduced).
Lung cancer is now the most common malignancy in both men and women. Smoking causes approximately 85% of lung cancer. Thus, we already have a cure for 100,000 men and 50,000 women who will get lung cancer each year! Stopping smoking is the answer to prevention. Otherwise, the cure for lung cancer is surgery, if it is possible. Chemotherapy and radiation are not very effective, but new lung cancer centers are being developed. These will focus upon early identification and intervention, and, of course, this will also mean smoking cessation. Hopefully, the newer drugs for lung cancer will be found more effective.
What about acute respiratory insults? The major lung disease spectrum cited here is the adult respiratory distress syndrome first described by the Denver group. This affects 150,000 patients each year. We are proud of the fact that 40-50% of ARDS patients survive, through therapies designed in Denver and now applied worldwide. We are also searching for better methods of prevention, and new drugs can help prevent acute lung injuries.
Dr. Thomas Petty, Professor of Medicine University of Colorado Health Sciences Center; Consultant and Faculty at HealthONE Center Denver, CO.
Insomnia, that is, the inability to fall asleep and stay asleep at appropriate times is a very common problem. I venture to say that nearly every person has had some degree of sleeplessness at one time or another. I am not talking about the restlessness of anticipation, such as just before holidays, big trips, or other special events. I am talking about when there is nothing particularly on your mind, either good or bad, and you just can’t sleep.
The basic reasons underlying sleeplessness are the subject of a great amount of study these days. Sometimes there is a clear-cut explanation, such as lack of oxygen during sleep or so-called sleep disordered breathing. Your see that our respiratory center has a lot to do with rate and depth of breathing during sleep, and if your respiratory center is getting mixed messages about how to breathe in case of emphysema, breathing regularity may become disturbed or temporarily interrupted. This will almost always awaken a patient because of the sensation that “something is wrong.”
When these definite abnormalities are found by a physician, specific corrective treatment can be prescribed. Many more patients have sleep disturbances for no known reason. Here is some advice about dealing with this common situation.
First, just recognize that sleeplessness is common and, by itself, is not harmful. Just remember that you will sleep the next day. If things are running through your mind or you are afraid of forgetting something important, turn on the light and make notes of your ideas, thoughts, or concerns. This will break the cycle of “things running through your mind.” It is even good to get up and do natural things that will promote sleepiness, such as reading, taking a warm bath, or drinking some warm milk. Why do these things work? Simply stated, they relax your mind so that natural sleep occurs, and there is a substance in warm milk called tryptophan which makes people sleepy.
I have left sleeping pills to last because they tend to be overused, but in certain situations mild amounts of tranquilizers or short-acting sleeping pills can be prescribed with safety by your doctor. Before relying on sleeping pills, just remember that some degree of insomnia is very common. In fact, that is why I am writing this Newsletter at 2:00 in the morning.
Dr. Thomas Petty, Professor of Medicine University of Colorado Health Sciences Center; Consultant and Faculty at HealthONE Center Denver, CO.
The Magnificent Lungs (Understanding the lungs and the role they play in your life)
A note by Dr Tom Petty, M.D.
Just about all of us are concerned about our health. Quite appropriately, the heart gets a lot of attention in this area; everyone knows that heart attacks are the number one cause of disability and death in this country. The heart is a remarkable pump that delivers blood to every organ in the body. When healthy, it does its job with a great amount of reserve. The popularity of jogging, walking, and other forms of exercise illustrates our new commitment to health through physical fitness.
It is amazing that only a few people have equal reverence for the lungs. After all, the lungs provide oxygen which is pumped by the heart and carried by the blood throughout our bodies—even to the heart itself!
Oxygen energizes every cell of the body. It is the key to the energy chain that keeps us living. A great amount of oxygen we take in is used to maintain cell and tissue structure.
Oxygen is required for all organ functions, including heart functions that are involved in every living activity. Oxygen is critical to the survival of all human beings. A shortage of oxygen affects every organ in the body. The brain has the highest oxygen requirement of all the organs. The heart has an immense oxygen requirement compared with the other organs in the body. The liver, kidneys, and all other organs require oxygen for their own vital functions. Thus, in states of oxygen deficiency, the whole body becomes robbed of vital energy.
Oxygen is involved in the process of metabolism, which converts food into the energy we need to live. The by-product of metabolism is carbon dioxide. The lungs remove carbon dioxide from the blood as it is returned from the tissues. When the lungs cannot exhale enough carbon dioxide, there is a toxic build-up, resulting in “acidosis,” an acid poisoning of all cells of the body. The brain, heart, and other organs are also impaired by carbon dioxide retention.
Understanding the lungs would be easy if they simply exchanged oxygen and carbon dioxide, but they do much more.
The lungs are the only organs in the body that receive the heart’s entire blood flow with each heartbeat. As blood from the veins flows to the right side of the heart and through the lungs, many of the body’s chemicals are either inactivated or activated by the lungs. For example, the lungs activate a hormone that controls blood pressure.
The lungs, through their normal function, affect our daily moods and emotions.
The lungs are the largest organ in the body. The total surface area is more than 100 square yards—the size of a tennis court. The delicate gas exchange membrane, or air-blood interface, is 1/50th the thickness of tissue paper. Millions of tiny capillaries carry red blood cells throughout the body, transporting oxygen in and carbon dioxide out. These red cells also contain mechanisms that defend against cigarette smoke, air pollution, and other noxious materials. Thus, the red cells are not only servants to every organ and tissue, but they are also the defenders against cancer, emphysema, and other lung diseases.
White cells, which defend us against infection, also traverse the lungs. In fact, at any one minute at least 17 billion white blood cells are cruising through our lungs. Billions are stored there, poised and ready to attack bacteria, viruses, and other infectious invaders that we inhale every day.
Nearly all of us know our height, weight, age, family background, and blood type. Virtually everyone has his or her blood pressure measured from time to time. Regular checkups of skin, breasts, and other organs can warn us well in advance of cancer. Yet rarely do we have a “lung checkup.” If the lungs are so critical to our health and happiness, why do we take them for granted?
Actually a “lung checkup” or vital capacity test is quite simple. The test measures the amount of air that can be blows out of fully inflated lungs. Vital capacity is a better predictor of longevity than other tests, including blood pressure, electrocardiograms, or blood tests. This breathing capacity has truly proven to be the capacity for life. But how many people know their own vital capacity? Testing devices are readily available, but unfortunately are used too infrequently in physicians’ offices. Indeed, two simple devices that cost less than $15 could be used by all Americans to test their vital capacity in their own homes.
The Effects of Smoking
You know that cigarettes are dangerous to those who smoke them. But even if you don’t use tobacco, you are not safe from the smoke emitted by someone else’s cigarette: passive smoke. Passive smoke contains more cancer-producing chemicals than the air in many chemical factories, uranium minutes, or asbestos factories. Cigarette smoke is more radioactive than many x-rays! A huge number of tobacco chemicals invade our body through the lungs unless we insist upon the right to breathe clean air. These chemicals can cause lung cancer, the most common fatal malignancy in both men and women. The carcinogens are also carried to other organs of the body, causing cancer of the bladder, uterus, and pancreas, etc. In fact, it is estimated that 30 to 50% of all cancer is caused by cigarette smoke.
Besides the risk of cancer, smoking doubles your risk of heart attack. And even if you don’t cancer or die from a heart attack, you are likely to develop chronic obstructive pulmonary disease (COPD), the fourth most common cause of death and second major cause of disability in our nation. Our society spends at least $2.5 billion a year for oxygen therapy and many more billions for respirators in intensive care units.
Tobacco kills approximately 1,500 Americans each day. But we continue to allow tobacco sellers to advertise their deadly products. It is estimated that 4,000 people have died in Bhopal, India since the world’s greatest industrial disaster in 1984, but we accept 450,000 deaths per year as a matter of personal preference. Court dockets are full of claims against the asbestos, minimal, and chemical industries. However, our billboards, magazines, and newspapers continue to sell heart attack, cancer, and COPD. Why do we continue to promote suffering and death?
What is the answer to this paradox?
1. The first step is to recognize the lungs as major health organs. We must identify lung health as the basis for a healthy, happy, long life.
2. We must learn about the condition of our own lungs and be able to protect them.
3. We must support legislation against smoking in public places and against tobacco advertising of all types, including the endorsement and sponsorship of sporting events.
4. Finally, we must continue in our research efforts to understand the basic mechanisms of lung injury through smoking. In the interim, before smoking is dramatically reduced in this country, we will continue to develop and evaluate new methods of care for COPD sufferers, as we have during the past 35 years.
Anatomy of the Lungs
The lungs should be considered “the environmental organ.” They are unique in their size and formation, and they interface with all the materials you inhale from the community environment, the work environment, and the personal environment. The lungs are made up of a series of branching tubes that provide the pathways for air entry and exit. These pathways, called bronchi, are exquisite in their design, with each tube branching twice: The major airway or windpipe (trachea) divides into two main bronchi, which in turn beget smaller and smaller orders of bronchi until some 22 divisions result in the final conducting passageways.
The respiratory or gas exchange function of the lungs begins in tiny sacs or folded structures (alveoli) attached to these tiny passageways. These smallest passageways continue to branch and finally connect with alveolar ducts, passageways thoroughly lined by alveoli. Each duct ends in a mass of alveoli. The avelolar-capillary membrane lines all of the alveoli and works as the blood-air interface. It allows life-giving oxygen into the blood and extracts the waste gas, carbon dioxide, from the blood. As stated earlier, this delicate membrane is only 1/50th the thickness of tissue paper, thin enough to transport oxygen and carbon dioxide, but still a barrier against fluid formation within the alveolar spaces.
The total surface of the alveolar membrane varies from 100 to 200 square meters, depending on the size of the person. The overall surface area of the alveolar membrane has frequently been equated to that of a tennis court. This comparison is really an underestimation! Thus, the lungs are by far the largest organs that make intimate contact with the environment.
The lungs are also the only organs of the body that receive all the blood from the heart with every heartbeat. Thus, any material in the bloodstream circulates through the lungs constantly. Some materials, such as small blood clots, can injure the membrane and cause the lung to leak fluid. Infections can cause pneumonia, and heart failure can flood the lungs. In these conditions, gas exchange becomes abnormal.
People who truly understand the lungs marvel at their complexity. Consider that roughly 100,000 small air passages that feed a membrane surface area greater than the size of a tennis court! This membrane wraps itself around at least 300 million alveoli and is lined with a myriad of tiny blood vessels called capillaries. Consider further the fact that approximately four quarts of air pass through the gas-exchange surface each minute, along with some five liters of blood, which traverse the capillary membrane. This magnificent machine occupies the chest cavity and, in all, is some 4 to 6 quarts of total volume. We certainly must consider the lungs the most exquisite packaging job in nature, and their function a splendid orchestration. Only the brain possesses greater complexity and capability in design and function.
Naturally, the lungs must be defended against outside damage, and recent research revealed some fascinating defense mechanisms. The nose acts as a filter, and the conducting air passages contain a protective mucous lining. Within the lungs, tiny hair-like cells called cilia sweep the air entering the lungs almost constantly, acting as janitors. Scavenging cells, called macrophages, are poised and ready to engulf particles that evade their sentinels. Macrophages are potent obstacles to damage from the environment, but these cells can release enzymes that damage the lung’s delicate structure.
Small amounts of normal lung fluids also help the lungs defend themselves. The surfactant system of the lungs allows easy filling and emptying of the lungs. Surfactant also provides an antibacterial and immune function to protect against infections.
Within the blood vessels of the lungs, an anti-clotting system combats small accumulations of damaging cells, aggregates, and small clots that enter the lungs from other parts of the body.
Thus, normal lung fluids are being formed and washed away constantly. The lungs have anti-irritants, anti-infectives, anti-enzymes, and immune defense mechanisms, all of which are coordinated to serve these organs well.
The gas-transfer function of the lungs is well understood today. (In fact, everyone should learn about this process, the essence of normal organ system function. Information on the topic is available in schools and in the numerous health-oriented articles that appear in the print media today). The biochemical or non-respiratory functions of the lungs are less recognized. We continue to marvel at the hormonal activities of the lungs that, as mentioned earlier in this chapter, regulate other functions of the body, possibly including the brain. Thus, the lungs work in cooperation with the brain, and are the main control system for the body. The lungs are unequaled in their diversity of functions and contributions to the health of the individual.
Thus, the chest, containing both lungs and heart, is not a “block box.” Let’s reconsider the orchestration of the lungs mentioned earlier in this chapter. This symphony includes 300 million alveoli and at least 100,000 small airways, as well as the larger airways, working together with each breath that leaves our body, some 12 to 20 times a minute. We consider the lungs to be the “pulmonary philharmonic” of our body. The heart, which pumps the blood, is the “cardiac choreographer.” For as words flow from a pen and move across the page, so the blood from the lungs is moved by the heart to serve all the organs of the body. But the “pulmonary philharmonic” and the “cardiac choreographer” must have a conductor. The “conductor” is the brain, our most vital control system. The whole human brain, including consciousness and awareness, is the conductor. And, as respiration and circulation are the “recital,” metabolism which fuels all bodily functions is the “melody.” Only the individual can perceive and know his or her own melody, the pitch, the tone, and the meter. In illness, we can all feel the decrescendo of despair. Can we once again ascend with a new cadenza and revel in rhapsody? Good music lasts and lingers on!
This brief essay and the suggested reading that follows are intended to stimulate further study, contemplation, and philosophizing about the lungs as the unique organs they are and about the various roles they play in the health and happiness of the whole human being.
Suggested Reading Scientific:
1. Murray, JF: The Normal Lung (The Basis for Diagnosis and Treatment of Pulmonary Disease). 2nd Edition, Philadelphia, W.B. Saunders, 1986.
A world renowned pulmonologist and early supporter of and contributor to the National Emphysema Foundation, Dr. Thomas Petty, M.D., passed away Dec. 12, 2009 in Denver, CO following a lengthy illness.
As a medical student, Dr. Petty’s first patient was a man with emphysema, an experience that shaped his career as evidenced by his interest and later accomplishments in Chronic Obstructive Pulmonary Disease (COPD) and pulmonary/respiratory illness.
He is recognized as having completed the original research which resulted in the extensive use of home or ambulatory oxygen and, later, liquid oxygen. Dr. Petty is also considered responsible for the widespread use of oxygen therapy through his sponsorship of the Long Term Oxygen Therapy (LTOT) Consensus Conference, which was launched in 1986.
In addition to his work with respiratory patients, Dr. Petty is also a well-known author and editor of patient-focused books, most notably Enjoying Life with COPD (1985). He has published more than 750 articles in medical journals and authored or edited more than 40 books.
Dr. Petty wrote freely and openly to COPD patients about coping with the disease, encouraging them to enjoy life and embrace their future. In Enjoying Life with COPD, Dr. Petty wrote: “Remember that birth, life and death are natural phenomenon.”
Regarded as the “Father of Pulmonary Medicine,” Dr. Petty advanced every significant area of pulmonary disease and many areas in critical care and sleep medicine during his lifetime. He is also highly regarded for his work in identifying Adult Respiratory Distress Syndrome (ARDS).
Dr. Petty served on and led the board of the Pulmonary Education & Research Foundation and was the organizer and founding president of the Association of Pulmonary Program Directors. He founded a quarterly newsletter, Lung Cancer Frontiers, and co-founded the International Respiratory Care Club. He served as president of the American College of Chest Physicians, was a board member of the COPD Foundation and a member of the National Emphysema Foundation’s medical advisory board for more than 30 years.
Dr. Petty also served as a professor of medicine at the University of Colorado Health Sciences Center in Denver and at Rush-Presbyterian-St. Luke’s Medical Center in Chicago. He was awarded the University of Colorado’s Silver and Gold Award for Excellence and earned a place in Colorado’s Pulmonary Physicians’ Hall of Fame.
Despite his extensive list of accomplishments, Dr. Petty always remained approachable with patients. His friendship was cherished by all who knew him personally – and many who did not. Dr. Petty is greatly missed by his daughter Caryn, sons Tom and John, eight grandchildren and his long time friend and colleague Louise Nett.