Alternatives to the hypoxic drive theory

Since 1960, several studies have demonstrated what really happens when CO2 retainers are exposed to supplemental oxygen.  The best explanation comes from John Haldane himself in what is now referred to as the Haldane Effect, and another process we refer to as ventilation/ perfusion (V/Q) mismatching.

1.  The Haldane effect:   This law was created by John Haldane, a pioneer of oxygen therapy.  He proved that as Deoxygenation of the blood increases its ability to carry carbon dioxide.  Thus, the less oxygen on hemoglobin, the more CO2 on hemoglobin.  CO2 attaches to unsaturated hemoglobin molecules. Oxygen is more soluble in water and therefore has a higher affinity for hemoglobin, so if you increase oxygen in the blood by supplemental oxygen, CO2 molecules are forced off hemoglobin and oxygen takes its place.  This causes an increase in CO2 in the blood, or an increased PaCO2.

Most people would simply increase their respiratory rate and blow off this CO2. Yet COPD retainers who are in respiratory distress may not have the capacity to increase their respiratory rate, so their respiratory rate remains the same.  This causes their PaCO2 to rise.

Now consider that this patient may have an elevated hemoglobin level after years of oxygen deprivation, and you're going to have lots of extra CO2 molecules roaming around the blood stream.  This may be on top the patients already elevated CO2 retention.

All these CO2 molecules are transported back to the lungs for ventilation to take place.  Yet because many alveoli are poorly ventilated (V/Q mismatching), and because the patients ability to increase ventilation is tapped out, PaCO2 levels will rise.

The Haldane effect was proven by a study described in 1996 in Critical Care Medicine, "Causes of hypercarbia with oxygen therapy in patients with chronic obstructive pulmonary disease." (1)

2.  V/Q mismatching:  Consider that V = Ventilation and P = Perfusion.  So, generally this is Ventilation/ Perfusion mismatching.  It is caused by increased airway narrowing due to airway remodeling, bronchospasm, and increased sputum production.  Where this occurs, the lungs are perfused but poorly ventilated.  It means that in areas of the lungs where V/Q mismatching occurs do not allow CO2 to enter the lungs, and oxygen to enter.

When an alveoli is poorly ventilated the vasculature around it will constrict so oxygen goes to alveoli that are ventilated well.  This is how that patient's body has made efficient use of his diseased lungs.

Now add 100% oxygen and you screw up this naturally occurring phenomenon.  Now the vasculature around that non-ventilating alveoli dilates, and this causes blood to be sent to the non functioning alveoli.  Now you have even greater V/Q mismatching and more CO2 that doesn't get out of the blood.  The end result, therefore, is an increase in PaCO2.

This theory was proven via a study completed in 1980 and reported in American Review of Respiratory Disorders, "Effects of the administration of O2 on ventilation and blood gases in patients with chronic obstructive pulmonary disease during acute respiratory failure," (2)

These two theories are far more viable than the hypoxic drive theory, and both have been proven by science.  Regardless, the hypoxic drive theory continues to be the gold standard theory.

References:

1. Hanson, et all, "Causes of hypercapnia with Oxygen Therapy in patients with Chronic Obstructive Pulmonary Disease," Critical Care medicine, 1996, volume 24, pages 23-28 (abstract available by link)  Source #3 above also indicates support for this theory (Caruano-Montaldo, ibid, page 218), and reference # 12 (Robinson, ibid, page 1527), and #13 (Dick, C.R., ibid)
2. Aubier, M, et al, "Effects of the administration of O2 on ventilation and blood gases in patients with chronic obstructive pulmonary disease during acute respiratory failure", American Review of Respiratory Diseases,  1980, Volume 122, pages 747-754 (abstract available by link) Source #3 above also indicates support for this theory (Caruano-Montaldo, ibid, page 218)

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What evidence proves the hypoxic drive theory wrong?

Ironically, and surprisingly, there has never been a real scientific study done to prove the hypoxic drive theory.  On the contrary, many studies have shown the theory to be nothing more than a myth.

For instance, in 1989 Greggory A. Schmidt M.D. and Jesse B. Hall M.D. wrote an article, "Oxygen Therapy and Hypoxic Drive to Breath:  Is There Danger in the patient with COPD?" that was published in Critical Care Digest questioning the popular hypoxic drive theory.  (1)

Schmidt and Hall reported that little science was used in coming up with this theory.  No COPD patients were given oxygen and had their ventilations simultaneously measured.  (1)

In fact, they report that in one study COPD patients were given oxygen and they found that "the rise in CO2 could not be accounted for by hypoventilation."

Likewise, a follow up study determined that supplemental oxygen to COPD patients caused decreased ventilation in some, unchanged ventilation in some, and normal ventilation in some. They wrote that "The commonest pattern was of early hypoventilation followed by a return to baseline.

Schmidt and Hall "attributed the rise in CO2 to an increase in the dead space to tidal volume ratio (also referred to as ventilation/ perfusion mismatching) consequent to oxygen therapy, though the mechanism for this change is unclear."

Abier et al in 1980 showed that 20 COPD patients in acute respiratory failure receiving 5lpm oxygen for 30 minutes showed a 14% reduction in minute ventilation with only a small rise in PaCO2, despite a large rise in PaO2.  They concluded that there was no correlation with the rise in PaCO2 and the fall in ventilation. (2)

Abier et al in 1980 also studied the effects of 100% oxygen on minute ventilation in COPD patients presenting with acute respiratory failure.  The concluded, once again, that despite the slight rise in CO2 and drop in minute ventilation, there was no correlation with the rise in PaCO2 and the fall in ventilation. (3)

In a 2000 study by Robinson et al, 22 COPD patients were given 100% oxygen and ventilations fell by an average of 20% for those who were CO2 retainers, yet the cause was determined to be due to ventilation/ perfusion mismatching, "not just a failure of ventilatory response to the increase in PaCO2."  (4)

A 2007 by Dick et al showed that oxygen induced hypercarbia was not caused by knocking out the drive to breathe.  In stable patients with COPD given 100% oxygen over a period of 15 minutes, oxygen saturations increased by about 7.6% and PaCO2 rose by about 6.6 mmgH, while minute ventilation was unchanged in all those studied. (5)

A 2014 study by Savi et all concluded the following:

Our results support the hypothesis that increasing the FiO2 in CO2-retaining COPD subjects on NIV does not cause any clinically important change in CO2 retention.  (6)

The also note:

The PaCO2 commonly rises somewhat when a patient with COPD receives supplemental oxygen, but carbon dioxide narcosis due to oxygen therapy is uncommon, and patients should not be kept hypoxemic for fear that oxygen therpay could aggravate carbon dioxide retention. The increase in CO2 is probably due to a change in dead space or shift of the hemoglobin-oxygen binding curve, rather than decreased respiratory drive.  The expected rise should not be specifically treated unless it is excessive, resulting in a trend toward acute respiratory acidosis on serial arterial blood gas analysis, with cenetral nervous system or cardiovascular side effects.  Carbon dioxide narcosis may occur with excessive FiO2, but is much less likely with low flow, controlled oxygen therapy.(6)

Despite all these studies, the hypoxic drive theory continues to be the gold standard theory regarding treatment of patients with COPD.  However, enough evidence now exists to support that supplemental oxygen is not as detrimental to COPD-CO2 retainers as once suspected.

References:

1. Schmidt, Greggory A., Jesse B. Hall M.D "Oxygen Therapy and Hypoxic Drive to Breath:  Is There Danger in the patient with COPD?" Critical Care Digest, 1989, 8, pages 52-53
2. Aubier M., Murciano D, Fournier M, Milic-Emili J, Pariente R, Derenne JP, "Central respiratory drive in acute respiratory failure of patients with chronic obstructive pulmonary disease, American Review of Respiratory Disease, 1980 volume 122, number 2, pages 191-199
3. Aubier M, Murciano D, Milic-Emil J, Touaty E, Daghfous J, Pariente R, Derenne JP, "Effects of the administration of O2 on ventilation and blood gases in patients with chronic obstructive pulmonary disease during acute respiratory failure," American Review of Respiratory Disorders, 1980, volume 122, number 5, pages 747-754
4. Robinson, Tracey D., et al, "The Role of Hypoventilation and Ventilation-Perfusion Redistribution in Oxygen-induced Hypercapnia during Acute Exacerbations of Chronic Obstructive Pulmonary Disease," American Journal of Respiratory adn Critical Care Medicine, 2000, volume 161, pages 1524-1529
5. Dick, C.R., et al, "O2-induced change in ventilation and ventilatory drive in COPD," American Journal of Respiratory and Critical Care Medicine," volume 155, no. 2, Feb., 1997, pages 609-614
6. Savi, Augusto, et al, "Influence of FiO2 During Noninvasive Ventilation in Patients with COPD," Respiratory Care, March, 2014, Volume 59, Number 3, pages 383-387

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Smoking not good for baby

Originally published healthcentral.com/asthma 11/11/12

Pregnant and smoke: here's your incentive to quit

In case we didn't have enough evidence that cigarette smoke is bad for asthma, new research suggests that moms who smoke while pregnant may be increasing the risk of their unborn child developing asthma by the time they are in preschool.

Of the 21,600 children studied, those who were exposed to cigarette smoke before birth were 65 percent more likely to develop asthma.  This is a significant enough percentage for us to once again take this issue seriously.  Mom's should not smoke while pregnant.

This study was published in the American Journal of Respiratory and Critical Care Medicine. You can read more about it at Medical News Today and  dailymail.co.uk.   An earlier study (you can read about at USC News) published in the same magazine discussed how smoking during pregnancy can cause DNA changes in the unborn child.  

When you smoke you are putting, along with the highly addicting nicotine, over 40,000 chemicals that you never would think about putting in your body.  Yet these chemicals are needed to make a cigarette and hold it together.  The following are some examples (Source: Healthliteracy.worlded.org): 

1. Carbon Monoxide:  Car exhaust
2. Tar:  Material to make roads
3. Arsenic: Rat poison
4. Ammonia: Cleaning products
5. Hydrogen Cyanide: Gas chamber poison
6. Cyanide: Deadly poison
7. Acetone: Nail polish remover
8. Butane:  Cigarette lighter fluid
9. DDT: Insecticides
10. Formaldehyde: To preserve dead bodies
11. Sulfuric Acid: Car batteries
12. Cadmium: Used to recharge batteries
13. Freon: Damages ozone

These are just some of the chemicals you are putting into your body.  These are the reasons when you smoke you are at increased risk for various cancers, heart disease, dementia, and lung disease. And by smoking, especially while pregnant, you are putting these same chemicals into your child's body.

This is a really good incentive for you to think about quitting smoking.  I encourage you to start the process now.  Please, just start thinking about it.  Then set a quit smoking date.  I think a good date is coming up.  November 15, 2012, is the Great American Smokeout.  If you need help or support, call 1-800-QUIT NOW

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Why is the government interested in VAP?

Your question: Why is the government interested in reducing nosocomial pneumonia and VAP?

My answer:  While the powers that be will tell you that the main emphasis of efforts to reduce nosocomial infections such as ventilator associated pneumonia (VAP) are to improve patient outcomes, this is not the complete truth.  Any time you have insurance companies and the government involved in the creation of guidelines to improve outcomes, the ultimate goal, or the bottom line, is saving money.

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How the hypoxic drive theory was born

While oxygen was discovered as early as the 18th century, it was not routinely used therapeutically until the early 21st century.  Still, it wasn't until the 1940s that physicains started realizing their were risks associated with its use, and 1960 when the hypoxic drive theory was born.

Oxygen was discovered in 1777 by Joseph Priestley. Despite its availability, it was not routinely used to treat medical conditions mainly because there was no convenient means of producing, storing, and delivering oxygen to patients.  Yet by the turn of the 21st century the first two of these obstacles were resolved, and it was up to John Haldane to resolve the third.

In 1922, Haldane wrote about his own research on oxygen in "The Therapeutic Administration of Oxygen."  During WWI he had developed a mask to conveniently deliver oxygen to soldiers suffering from pulmonary edema due to poison gas.  After the war he continued his experiments in hospitals.

Soon thereafter oxygen tanks became more and more common at the patient bedside, and oxygen was tried on patients with pulmonary edema and pneumonia, although sometimes for patients with cystic fibrosis, asthma, emphysema and chronic bronchitis.  (7)

Once oxygen was administered to COPD patients, it was soon realized that some of these patients became lethargic and lost their drive to breathe.  It was soon learned that it was the oxygen causing this because it caused their carbon dioxide (CO2) to rise.

In 1949 a case was documented where a man with emphysema "lapsed into a coma after receiving oxygen therapy but rapidly recovered after the oxygen was removed," according to Nicola Cooper, Kirsty Forrest, Paul Cramp in their 2006 textbook, "Essential guide to acute care."

The text also explains that "in 1954 a decrease in ventilation in 26 out of 35 patients with COPD given oxygen therapy, with a rise in PaCO2 and a fall in pH.  No patient with a normal baseline PO2 showed these changes.  In a further study it was showed that stopping and starting oxygen therapy led to a fall and rise of PaCO2, respectively."  (8)

The concern became so great that in the 1950s a study was performed that ultimately lead Dr. EJM Campbell to give a lecture to pulmonologists in 1960 about the dangers of giving too much oxygen to COPD patients.  It was this lecture that forever linked hypoxic drive with COPD, and gave birth to the hypoxic drive theory.  (9)

Yet instead of a scientific theory being treated as a scientific theory it was treated as scientific fact, and this began the accepted practice of keeping patients in much need of supplemental oxygen hypoxic.

The medical profession decided the hypoxic drive theory sounded good so it must be good. The Hypoxic Drive Theory thus became the law of COPD land. Any evidence to the contrary would be rejected.

Of interest here is that the study Campbell referred to in his lecture consisted of only four COPD patients. Regardless, the theory quickly gained acceptance by the medical community, and became the gold standard when taking care of patients with COPD

Since then a few studies have confirmed the theory, although many have shed doubt on the theory.  Regardless, due to Campbell's presentation, the theory had already stuck in the minds of physicians and medical professors.  They had now become dogmatic to the theory, and closed minded to any evidence to the contrary.   (10)

References:

1. Schmidt, Greggory A., Jesse B. Hall M.D "Oxygen Therapy and Hypoxic Drive to Breath:  Is There Danger in the patient with COPD?" Critical Care Digest, 1989, 8, pages 52-53
2. Wilkins, Robert L, James K. Stoller, ed. "Egan's Fundamentals of Respiratory Care," 2009, pages 309-310
3. Caruana-Montaldo, Brendan, et al, "The Control of Breathing in Clinical Practice," Chest, 2000, 117, pages 205-225 (This article also provides a good review of the central and peripheral chemoreceptors and the drive to breathe)
4. Wojciechowski, William V., "Entry Level Exam Review for Respiratory Care:  Guidelines for success," 3rd edition, 2011, U.S., page 487?
5. Cooper, Nicola, Kirsty Forrest, Paul Cramp, "Essential guide to acute care," 2nd edition, 2006, Massachusettes, page 24
6. Tines, John Hudson, "Exploring the History of Medicine," 1999, great read for obtaining a pithy history of medicine
7. Glover, Dennis W. , "History of Respiratory therapy," 2010, page 94, great read for obtaining a pithy history of respiratory therapy
8. Cooper, Nicola, Kirsty Forrest, Paul Cramp, "Essential guide to acute care," 2nd edition, 2006, Massachusettes, page 24
9. Campbell, E.J.MRespiratory Failure,"  The British Medical Journal,  June 1965, 1451-1460 (article provided by link)

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Hypoxic drive myth, another exmaple of a dogmatic medical profession

A dogmatic doctor.

Despite convincing evidence that sheds doubt on the hypoxic drive theory, medical professors continue to teach it as fact, and physicians continue to worship it as the Holy Grail.  This is not, however, the first time the profession has been dogmatic, and it probably won't be the last, either.

There is actually convincing evidence suggests that a "reduction in hypoxic ventilatory drive may not be the sole mechanism causing increasing hypercapnia in (COPD patients)." (3)

Now, before I go on, it must be noted here I have much admiration and respect for the medical community.  The history, facts, and opinions shared in this post should in no way diminish my respect for the profession.

Yet while I respect and admire them, I also understand the medical profession is notorious for being proud, dogmatic, and slow to accept new ideas.

Take 1543, for example.  Back then it was normal for an assistant to dissect a human corpse while a professor read from one of Galen's books.  Andreas Vesalius observed that what was being read was different from what he was seeing.

For instance, Vesalius observed that Galen's writings described the sternum as having eight parts, yet the human sternum being dissected in front of him had only three parts.

Later, when Vesalius was dissecting an ape, he learned it was the ape that had an eight part sternum.  He learned that Galen had based his writings on dissections of apes.  This makes sense, considering in Galen's day it was illegal to dissect a human corpse.

In the 16th century, artists like Michelangelo knew more about the human anatomy than physicians, so Vesalius hired Johannes Oporinus to draw accurate pictures of human anatomy , and Vesalius published the first ever book on human anatomy De humani corpus in 1543.

Yet Galen could nary be wrong, and Vesalius was laughed out of town by a dogmatic profession.

In the end, however, Vesalius was proven right, and his wisdom gave birth to the science of human anatomy.

In 1816, Rene Laennec invented the stethoscope.  Instead of the medical community embracing and adapting the tool that would greatly improve their diagnostic skills, they mocked Laennec.  They were too proud to carry such a frivolous tool.

In the end, however, this tool became a required tool for all physicians.

In 1847, Ignaz Semmelweis observed that moms whose babies were delivered by medical students were far more likely to die of child bed fever compared to moms whose babies were delivered by midwives. He proved that this was because the medical students did not wash between patients, while the midwives did. He made it mandatory for the students to wash their hands as the midwives did, and this resulted in mom's dying from childbirth plummeting.

Back then, you see, medical students were proud to show how hard they worked by blood on their hands and aprons. So, since Semmelweis could offer no scientific proof why hand washing resulted in fewer deaths, he was mocked and forced to leave town.  (6)

In the end, however, semmelweis was proven right when, in 1864, Louis Pasteur proved the germ theory of disease.

So it is quite evident that physicians being dogmatic about the hypoxic drive theory, despite convincing proof that it's nothing more than a myth, are hesitant to give up on it.

References:

1. Schmidt, Greggory A., Jesse B. Hall M.D "Oxygen Therapy and Hypoxic Drive to Breath:  Is There Danger in the patient with COPD?" Critical Care Digest, 1989, 8, pages 52-53
2. Wilkins, Robert L, James K. Stoller, ed. "Egan's Fundamentals of Respiratory Care," 2009, pages 309-310
3. Caruana-Montaldo, Brendan, et al, "The Control of Breathing in Clinical Practice," Chest, 2000, 117, pages 205-225 (This article also provides a good review of the central and peripheral chemoreceptors and the drive to breathe)
4. Wojciechowski, William V., "Entry Level Exam Review for Respiratory Care:  Guidelines for success," 3rd edition, 2011, U.S., page 487?
5. Cooper, Nicola, Kirsty Forrest, Paul Cramp, "Essential guide to acute care," 2nd edition, 2006, Massachusettes, page 24
6. Tines, John Hudson, "Exploring the History of Medicine," 1999, great read for obtaining a pithy history of medicine

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What is the hypoxic drive theory?

The hypoxic drive theory was born in the 1950s, was given credulity in 1960, and was first disproved in 1987.  (1)  Since then the theory, known to some as the myth or the hoax, has become one of the most hotly debated theories in all of medicine.

The crux of the theory is that the main drive to breath comes from neurons in the medulla oblongata at the base of the brain.  These neurons receive signals from central chemoreceptors on the medulla and peripheral chemoreceptors located in the bifurcations of the aortic arteries and the aortic arch.

Respiratory rate is adjusted to maintain a normal acid base balance (pH) throughout the body.  The majority of the times, the central chemo receptors send signals to the brain that control breathing. They monitor carbon dioxide (CO2) levels.  When CO2 levels are high a signal is sent to speed up the drive to breathe to blow off the excess CO2.  In this way, CO2 is our main drive to breathe.

The peripheral chemo receptors send a signal to breathe when the partial pressure of oxygen in the arteries (PaO2) is less than 60. This is referred to as the hypoxic drive.  This hypoxic response is far slower than signals sent by central chemoreceptors, and therefore the hypoxic drive has only a minor role in breathing.

In COPD patients, chronic airway obstruction due to bronchospasm and increased mucus secretion blocks air passages, and as a result many alveoli become ineffective at ventilating (CO2 cannot get out and oxygen cannot get in).  For these patients, this results in a chronically elevated CO2 (greater than 50), and lowered oxygen levels (SpO2 less than 90 and Po2 less than 60). (2)

As CO2 rises, bicarbonate (HCO3) falls in order to compensate and prevent acidosis (a drop in pH, or a pH less than 7.35).  The result here is that many of these patients normally live with something like a PaCO2 of 50, a PaO2 of 50, and a Bicarb of 30.  These patients are aptly referred to as CO2 retainers, or simply retainers.

In many instances students are incorrectly taught that all COPD patients are retainers who breathe under influence of the hypoxic drive.  The truth is that less than 25 percent of chronic CO2 retainers use the hypoxic drive to breathe, (4) and it's not as significant as once believed.

In fact, of patients who present to hospitals in respiratory distress, half will have reversible CO2 retention, and half will be chronic CO2 retainers.  (5)

The hypoxic drive theory has it that the high CO2 may make the chemoreceptors tolerant of the high CO2, and thus CO2 ceases to be that person's drive to breath.  These patients are your prototypical CO2 retainers. The hypoxic drive theory, thus, states that many of them are hypoxic drive breathers.

Those who believe in the theory believe if you give these patients too much oxygen, enough to drive their PO2 above 70, then you will blunt their hypoxic drive and knock out their drive to breathe.  Their respiratory rare will slow, their CO2 will therefore rise even more, acidosis will occur, the patient will become lethargic (very sleepy or somnolent), and ultimately they will stop breathing.

It is for this reason that most medical experts champion for never over-oxygenating patients who are CO2 retainers. The experts recommend using a nasal cannula set at 2-4lpm, and never higher.  Or, if their respiratory rate is sporadic, to use a venturi mask set no higher than 40% FiO2.

These experts say that if the CO2 rises, that the FiO2 should be lowered.  This has resulted in many physicians accepting PO2s in the lower 80s and even the upper 70s in certain patients.

Yet this often results in the ire of caregivers taking care of these patients, because they are the ones who have to watch them suffer from dyspnea, or air hunger, or the feeling they can't catch their breath.

It has also resulted in ire because many of these patients are placed on 100% oxygen with no ill effect.  Many of these patents have been given breathing treatments using oxygen, estimated to be about 60%, and have never seen any patient drop dead during a breathing treatment.

It was evidence like this that made clinicians second guess the hypoxic drive theory.  It was from here that various studies were done to show, once and for all, whether the hypoxic drive theory is a fact, or whether it's nothing more than a medical myth.

What in turn happened was that, even though most studies proved the theory was in fact a myth, the subject became even more controversial.

References:

1. Schmidt, Greggory A., Jesse B. Hall M.D "Oxygen Therapy and Hypoxic Drive to Breath:  Is There Danger in the patient with COPD?" Critical Care Digest, 1989, 8, pages 52-53
2. Wilkins, Robert L, James K. Stoller, ed. "Egan's Fundamentals of Respiratory Care," 2009, pages 309-310
3. Caruana-Montaldo, Brendan, et al, "The Control of Breathing in Clinical Practice," Chest, 2000, 117, pages 205-225 (This article also provides a good review of the central and peripheral chemoreceptors and the drive to breathe)
4. Wojciechowski, William V., "Entry Level Exam Review for Respiratory Care:  Guidelines for success," 3rd edition, 2011, U.S., page 487?
5. Cooper, Nicola, Kirsty Forrest, Paul Cramp, "Essential guide to acute care," 2nd edition, 2006, Massachusettes, page 24

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5 coughing techniques for COPD patients

The following was originally published at healthcentral.com/copd on May 14, 2014. 

Best coughing techniques for COPD

The lungs of people with chronic obstructive pulmonary disease (COPD), particularly chronic bronchitis, tend to produce lots of secretions that may become thick, hard to cough up, and make breathing difficult. When this happens, it’s very helpful to learn techniques that will help you generate a good, strong cough.

Keep in mind here that lungs are normally sterile. A cough, therefore, is a natural immune response to keep particles in the air from entering sterile lungs. Without this response, germs may enter your lungs and cause infections such as pneumonia.

Sometimes particles will enter the lungs of healthy people. When this happens, these germs will be balled up in a wad of mucus that is brought up to your upper airway to either be swallowed or spit up. Mucus that is ready for swallowing or spitting up is called phlegm.

The natural progression of COPD causes changes that alter this natural response:

1. Tissue damage: Damage to the tissues lining your air passages reduces your body’s natural mechanisms for moving up secretions.
2. Airflow limitation: Narrowed air passages and loss of lung tissue makes it so you are unable to generate enough flow to create an effective cough.

The end result here is that secretions become trapped in diseased lungs. These secretions may become thick over time and block air passages, thus making it hard to breathe. Patients in this situation may greatly benefit from what we in the medical profession refer to as the “Pulmonary Toilet.” The technical term is bronchial hygiene.

The name “Pulmonary Toilet” may sound kind of gross, but the name is actually quite fitting. It means that the doctor will do anything and everything to help your body break up and remove these secretions.

It usually begins with using an inhaled bronchodilator, either with an inhaler ornebulizer. Bronchodilators open up air passages to make breathing easier and allow for the release of trapped secretions.

The challenge now becomes how to get these secretions to your upper airway. Here are three of the best techniques to help you create an effective cough.

1. Deep coughing: Take as deep of a breath as you can, and hold it for 2-3 seconds. Then, using your stomach muscles, force this air out of your lungs. This will help to knock secretions loose and force them to your upper airway.

2. Huff Cough technique: Take a deep breath and, using your stomach muscles, make a series of three rapid exhalations. When you do this you will be making a “ha, ha, ha” sound. This will help vibrate secretions loose and bring them to your upper airway. This is very helpful for people with very severe airflow limitation. Check out this YouTube huff cough video for a quick demonstration.

3. PEP therapy: This is accomplished using a small, handheld device called a flutter valve or acapella. You sit on the edge of a bed or in a chair, and exhale into the device. While exhaling, vibrations will be felt in your air passages that are meant to knock loose secretions sticking to your airways. A positive pressure is also created that keeps your air passages open and helps move these secretions to your upper airway. Continue exhaling into the device until you feel loose secretions in your airway that are ready to be coughed up. A therapy session using this device may take only a few breaths, but for some patients, especially those with very limited airflow, it may take 10-15 minutes, or several exhalations. Check out these Youtube videos: “How to use a Flutter Valve” and “Acapella Vibratory PEP Mucus Clearance Device.”

4. Chest Physiotherapy (CPT): This procedure will require the assistance of another person. In the hospital setting this will include your respiratory therapist. You will be required to sit or lie in different positions while the therapist claps on your chest and back over your lungs. The idea here is vibrations caused by the clapping will loosen secretions. The procedure may take anywhere from 5-20 minutes. Due to limitations caused by your disease, you may be limited to sitting, or lying on your side using pillows. This YouTube chest percussion demonstration shows proper technique while sitting. The Cystic Fibrosis Foundation describes the procedure best in this Consumer Fact Sheet.

5. Combination: This is where you use a combination of the above techniques. It will generally start with an inhaled bronchodilator, followed by PEP therapy or CPT, followed by deep coughing or huff coughing.

Bottom line: While most people take coughing for granted, people with certain lung diseases aren’t able to do this. Instead, conscious efforts must be made to loosen and bring up secretions. The ideal method is whatever one you and your physician decide works best for you. These techniques may be performed on an as-needed basis, or scheduled 2-4 times per day.

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How to create a successful blog

Your question:  You seem to have a pretty successful blog here.  Can you give some tips on how to start a blog and write good posts like you do?

My answer:  Thanks for the kind words.  There are a few keys to starting up a blog that I think other bloggers would agree with.

1.  Think of a pithy name for your blog that is relevant to your content.  For instance, I put "Respiratory Therapy" in my header so that it would come up in searches for "respiratory therapy."

2.  Create a header for your blog that will catch the eye of anyone who clicks on your blog and reveal what the blog is about.  You can actually create your own headers by going to Google documents, click on file, click on new, and click on drawing, and click on page set up.  In this space you will type in pixels the dimensions of your header.  These can be learned by right clicking on the top of your blog, clicking on "page elements" and the html of your header will appear, revealing the height and width of your header.  Type in these dimensions into "page set up."  Then you can go to Google images to to select pictures for you header, or take your own pictures.  You can then download the images to your header, separate into layers, crop as desired, and type in your blog name and subheading if desired.  Similar programs are also available on Microsoft Word and other programs you have to pay for, but this one is free and easy.

3.  Write content that is related to your blog name.  Since mine is about respiratory therapy, I try to make most of my content relative to respiratory therapy.  However, at times I expand this to medicine and hospital life in general.

4. Write a minimum of three posts every week.  If you write any less readers who discover your blog may lose interest.

5.  Keep posts pithy, which means that each post should only cover one subject.  Make a point, and, whenever possible, add your opinion to posts.  Surely people will come to your blog for facts, but they also want your opinion, which is the purpose of a blog.

6.  Tell people what they already know but never get to say or read about elsewhere.  Like Rush Limbaugh or not, what he does is tell conservatives what they already know and never get to read about in newspapers.  It is this approach that has made him the most listened to voice on radio.

7.  It's okay to write facts.  Facts are your friend. It's one thing to form opinions, but opinions based on facts are the most interesting and most reliable.

8.  It's okay to state your opinion, even if it's about politics:  While facts are important, people come to your blog to hear what you have to say about things. You can write about politics from time to time, and you can let people know what your political views are.  This will not throw people from your blog so long as you don't over do it.

9.  Keep old posts hot by linking to them:  Blogger makes it easy to link to older posts.  This also helps to keep your readers on your blog, making them more likely to come back and read more.

10. Link to other blogs, news items, studies, etc. that are relevant to your post.  This helps show your credibility and reliability.

11.  Use spelling and grammar checks:  You do not have to be excellent at grammar and spelling to be a good writer anymore.  All you have to do is use the tools that are available for free.  You can place your post on a Google document page, or you can just use the spell check provided by Blogger.  I recommend doing both.  Correct grammar and spelling sows you are serious. Besides, there are people who will tune you out if you have too many errors.

12.  Take the time and make the time  Take the time to sit down and write, especially when you have a good idea.  Keep a notepad on you at all times so you can write down your ideas and don't have access to your key board.  Then make the time when all your other chores are concluded and write.

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Battle begins over 2nd hand smoke and e-cigs

Even while some people still smoke, I think it's safe to say that the battle against cigarette smoking has essentially been won.  According to the Centers for Disease Control and Prevention, in 1965 42% of the population smoked, and today it's down to 10%.  I think that's significant progress.

Most people, even smokers, now accept smoking is deadly.  The Surgeon General's office reports that over 20 million people have died from smoking related illnesses since 1965.  Science has proven this is probably due to the over 7,000 chemicals inside cigarettes, 70 of which have been linked to cancer.  The Institute of Medicine reports that 2nd hand smoke increases the risk of heart disease by 25-30%.

In fact, the battle has been so successful that even the dangers of second hand smoke, which at one time were considered harmless, are now commonly taught in schools.  Most people are now aware that exposure to second hand smoke may be just as harmful as first hand smoke.

Obviously there is still progress to be made.  Efforts are ongoing to finish the job of getting America over its addiction to cigarettes.  Yet the fight has advanced, somewhat to other areas.  Not satisfied with just getting people to quit smoking, some lawmakers have moved on to 3rd hand smoke and e-cigarettes.

Surely there are chemicals emitted from the stagnant smoke that lingers on furniture and carpet on rooms and vehicles where someone recently smoked.  Surely there are chemicals in e-cigarettes that are harmful, as the CDC has reported an increase in e-cig related calls to poison control offices.

While there are always advantages to public relations campaigns to encourage people to make wise choices, the battle against those individuals who continue to smoke even though they know it will kill them, and the battle to get people not to smoke e-cigs, and the battle to prevent someone from smelling cigarette smoke on someone's clothing, should be left to educational efforts.

Eli Lehrer recently wrote an article regarding this at National Review called "Diminishing Returns: The Campaign against (if you can believe it) third hand smoke."  He states that some states have even outlawed smoking e-cigarettes in public, studies don't conclude there are no risks to the smoker, although they do conclude risks to bystanders are negligible.

The author says:

This isn’t to suggest that e-cigarettes are safe. They contain nicotine, a very addictive stimulant that, like all stimulants, has the potential to cause heart problems. The fact that they’re quite addictive and may have long-term risks nobody has discovered (they’ve been on the market for less than a decade) is good reason to keep them away from children and out of schools, daycare centers, and medical facilities. Although not perfect, newly issued FDA regulations, which would ban sales to minors nationally, take a much more sensible approach to e-cig regulation than most localities have to date. But, whatever their dangers, e-cigarettes aren’t the same as cigarettes. People who use them instead of tobacco cigarettes can expect at least some of the same health benefits as those who quit smoking. And nothing suggests that their vapor is anything like secondhand smoke. Indeed, almost all research indicates the opposite.

He concludes:

The preponderance of the evidence indicates that both thirdhand smoke and e-cigarette vapor are the chemical equivalent of dirty looks. They may well be unpleasant or offensive to some people. But the public health case against them appears weak to nonexistent. Public policy would do well simply to leave them alone.

I would tend to agree.

The main crux of the battle against first and second hand smoke was that the person smoking was trampling on my natural right to breathe fresh air.  To extend this battle to third hand smoke and e-cigarettes would require taking the battle into a person's home, further trampling on personal liberties.

As Lehrer notes, "If thirdhand smoke or e-cig vapor caused the same ills, another campaign might be warranted. But they probably don’t."

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Subglottic suctioning

Nearly every study done on the subject shows that the leading cause of ventilator associated pneumonia to be caused by secretions pooling above the endotracheal tube cuff, resulting in gradual, micro-aspiration.

According to studies done as far back as 2002 and reported on by the Centers for Disease Control and Prevention (CDC) suggest that subglottic suctioning may help reduce the risk for micro-aspiration.

A CDC report notes:

The endotracheal tube prevents glottic closure. As a result, the patient is unable to cough and remove secretions in a natural way. However, accumulation or pooling of oropharyngeal secretions above the endotracheal tube cuff occurs and then these fluids can be aspirated. See figure. 

Removal of these secretions by suction can reduce the risk of aspiration and may be the most cost effective and safe intervention. Four studies have shown subglottic suction to be safe and effective,14,38-40while only one study showed no difference in colonization. Figure 2 shows one method of performing subglottic suction with a separate suction catheter placed into the sub-glottic area.

Various ETTs are now available that allow for subglottic suctioning. Studies suggest that ETT that allow for subglottic suctioning help reduce the risk for VAP.
Whether an institution has them depends on budget, and on how the powers that be perceive the results of the various studies.

References:

1. Van Hooser, Theron, "Ventilator Associated Pneumonia: Best Practice Strategies for Caregivers," 2002, http://en.haiwatch.com/data/upload/tools/VAP_CEU_Booklet_Z0406.pdf, Kimberly Clark Co., accessed 4/21/14
2. "Intubation And VAP: A Complex Condition Requires Bundled Solution," rtmagazine.com, http://www.rtmagazine.com/2014/04/intubation-vap-complex-condition-bundled-solutions/, accessed 4/23/14

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Types of asthma: the secret puffer

The following was published on healthcentral.com/asthma on 12/26/12

The furtive asthmatic: the secret puffer

If I'm feeling short of breath when there's people around, I pretend to be fine.  I remember many times in high school, way back in the 1980s to date myself, concentrating on my breathing, watching the hands of the clock, as the teacher lectured.  I didn't want to interrupt the class.

No, that's not true.  The real reason had nothing to do with interrupting the class, it had to do with me.  I didn't want attention.  I didn't want to be in the spotlight.  I didn't want sympathy.  I didn't want to have to talk about myself.  I didn't want people feeling sorry for me.  I didn't want people to worry about me. 

Funny thing is, everyone knew I had asthma.  Funny thing is, everyone still knows I have asthma. Yet I'm still a secret puffer.  I'm still a furtive asthmatic. 

I only use my inhaler in private.  It's so much easier that way.  It's so much easier because I don't have to explain myself. 

I used to think I was the lone secret puffer, that is until I met some really cool asthmatic bloggers who wrote about this same thing.  You can't imagine how neat it was to learn that other asthmatics do the same thing.  It's also neat the way we asthmatics understand each other, mainly because of the "Wow! You do that too!" moments. 

Yet now that I'm an adult it's a little easier to be a furtive asthmatic.  Now, of course, my asthma is much better controlled, so the attacks are less frequent and much milder.  Yet when they do occur I can easily excuse myself and puff away -- in secret.  No questions asked.  No sympathy. 

I think it's okay to be a secret puffer, although it could pose some problems.  Like, what if you are a teenager and you're pretending to be fine when you're not.  And you're furtively using your inhaler way too often.  And your parents don't know you're doing this, and therefore can't help you. 

Well, that used to be me. I bet some adults do this too. If so, yeah, that ain't good.  So it's okay to be a furtive asthmatic so long as you still follow  your asthma action plan.  You do have an asthma action plan, right?  If not you can follow this link to learn more. 

So it's okay to be a furtive asthmatic, as most of us are.  I just want to remind all of you furtive asthmatics out there -- and you know who you are -- to make sure at least one person in the room knows your secret. This could be a teacher, parent or friend. 

This person should be someone who knows your asthma triggers, and the signs and symptoms you're having trouble.  This person should be willing and able to say, "Hey, you shouldn't be doing that," or "Hey, you need to seek help."

Check out the other 11 types of asthmatics by clicking here.  

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What is the treatment for VAP?

Question:  What is the treatment of ventilator associated pneumonia (VAP)?

Answer:  Treatment is usually a broad spectrum antibiotic until the specific bug and effective antibiotic is isolated. Other than that, treatment generally includes supportive, and may include oxygen therapy, beta adrenergic therapy, bed rest, etc.  An effort should be made to maintain adequate oxygen saturation.  If a patient cannot maintain an SpO2 of 92% or greater, or 88% or greater if the patient has a chronic lung disease, then BiPAP therapy, or intubation and mechanical ventilation, must be considered as options

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All the lonely people

Back in 1993 I graduated from college and felt very lonely.  I completed college, and realized I did not want to be what I went to school for.  I was hired as a journalist, and I hated it.  I knew I was a good writer, but I got a serious bout of writers block.  I quit, and then for the rest of the year I felt depressed and lonely.

I felt lonely because I felt there was no one I could talk to.  My dad didn't want me to quit my job, mainly because he said I would get better with time and learn to like it.  I knew I would not get better, and not learn to like it.  I felt like I had taken a wrong path.  I spent many hours wondering why God had allowed me to take this journey.  I wondered how I was going to get out of it.

I couldn't help thinking of this recently as I attended two different Masses where the Priest talked about "all the lonely people."  They both began their sermons by singing the following lyrics by the Beatles:

All the lonely people

Where do they all come from?

All the lonely people

Where do they all belong?

The moral of both these sermons was this: if you believe in Jesus, you are never alone.  If you believe in the Lord, God, you are never alone.  This is essentially the message of John 14:15-21:

If you love me you will keep my commandments.

I shall ask the Father, and he will give you another Paraclete to be with you for ever,

the Spirit of truth whom the world can never accept since it neither sees nor knows him; but you know him, because he is with you, he is in you.

I shall not leave you orphans; I shall come to you.

In a short time the world will no longer see me; but you will see that I live and you also will live.

On that day you will know that I am in my Father and you in me and I in you.

 Whoever holds to my commandments and keeps them is the one who loves me; and whoever loves me willbe loved by my Father, and I shall love him and reveal myself to him.

One priest said this is similar to those moments, as parents, that we hold the hands of our children.  Yet then there comes a time as parents you have to let go and allow your child to walk on his own and hope you taught well.  Usually, your children DO take steps on their own, and they do well.  This is how they learn to become independent.

Similarly, there are times when Jesus holds our hands, and then there are times when he lets go, allowing us a chance to walk on our own.  These will be the times when you feel lonely.  Yet those who believe will know that the Lord is right there all along.  We continue to pray for the Lord to reveal himself, to show us that he is still there.

It is in these moments we pray words, and we seek for our prayers to be answered.  Yet, for long periods of time, sometimes it seems, our prayers go unanswered.  Yet we continue to pray, because, deep down, we continue to believe; we continue to have faith.

And then, usually at unexpected moments, he shows us that he is there.  These are the moments that, as a parent holds the hands of his child once again, that God does the same for us.

Those of us who believe will have those moments when we feel His hand, once again, upon our shoulders.  Perhaps this will be a moment where the sun shines bright upon your shoulder, and you are hit with a revelation that you are with God; You are hit with the revelation that your prayer has already been answered; you are hit with the revelation that the Lord has been with you all along.

I had such a moment back in December of 1993.  My brother David encouraged me to visit him in Kentucky.  One evening he and his wife were gone, and I was lying on the floor with a journal in front of me.  A refreshing breeze wafted over me and my journal, ruffling the pages.  At the same time a ray of sun shined on me, and a shiver went up my spine.

That was one of those moments when the Lord grabbed me by the shoulder and held me, guiding me.  At that moment it occurred to me that I was going to be a respiratory therapist. The next day I called my mother, thinking she'd be angry with me for starting all over, but instead she was fully supportive.  That was when I realized God had talked to her about it too.

And it's not like we need the support of our parents to change courses in life, although, as most of us know, it surely helps.  It helps to know that you are not taking this journey alone; that you have those who support you.

Over time I realized that not only did God touch me in that moment when the sun shined upon me, but he was also guiding me all along.  He walked with me during all those asthma attacks. He walked with me through journalism school. He walked with me through advertising school. He walked with me when I was working for the Lake County Star.  He walked with me that year I felt lonely.

The skills I obtained during that time allow me to share the word with all those I meet, and all those who read the words I write.  So, while sometimes we feel as though our prayers are not being answered; that the Lord is not listening, chances are, our prayers have already been answered.

20 tips for writing great blog posts

Your Question:  What are some ideas on how to write good blog posts?

My Answer:  Ideas for how to write posts:  I learned in journalism school the following "Elements of Good Writing:"

1. It is precise:  It contains no more words than necessary to make your point.
2. It is clear:  It's easy to read; has good flow
3. It has a pace appropriate to the content: This actually should be easy in a blog post considering they are "supposed" to be short and sweet (pithy) anyway.  The reader should use words to paint a story that is enjoyable to read.  Use unique techniques making the post readable.  Be creative.  
4. It uses transitional devices that lead the reader from one thought to the next: These may be words such as however, and, therefore, plus, 
5. It appeals to the reader's senses: Appeal to the sense of smell: The maggots over the patients legs had a putrid smell like rotting flesh.  Appeal to emotions: tears rolled down her eyes as she watched her father take his last breath. Appealing to senses helps to drive a person deeper into your post.
6. It uses analogies:  These permit writers to show similarities and contrasts.  Similes show similarities by using "like" or "as."  For example, The doctor gentle hands were smooth as a pearl in a bucket of peas. After crossing the finish line at the Boston Marathon, her legs felt so rubbery they wobbled like jelly. 
7. Each sentence is on one idea or thought: Sentences are pithy and simple and relevant. It's okay, in a blog post, to have a one or two sentence paragraph. This, actually, is preferred, and makes reading easy. It's really hard to read long, blocks of words.  Plus, long blocks of words are hard to read on many electronic devices. 
8. A post must have a beginning, middle and end.  The first paragraph should summarize the post, the middle should provide the facts and opinion, and the conclusion should wrap it up.  The best conclusions tie in with the opening paragraph. 
9. Keep it pithy:  Posts are pithy, generally 1-2,000 characters, but never greater than 4.  However, sometimes a long post may be necessary when there are lots of facts to share.  This is okay too. But just don't over do the long posts, and make them worth reading.
10. Use lists:  One of the best ways to make a post pithy to to limit it to a list: The ten reasons respiratory therapy school is harder than nursing school, or the 5 types of breathing methods for COPD patients.  This is the most common form of posts that I use on all my blogs. 
11. Precision:  Words should be used precisely.  Every word should have meaning, no word should be superfluous. 
12. Think clearly:  Make your point and be done.
13. Admit when you are wrong:  One of the things politicians never learn is that it's okay to change your mind and to admit to being wrong.  This is the key to maintaining credibility.  However, so long as you base your opinions on facts, or based on the words of other credible people, you should be okay.
14. Use quotations:  Quotations are important when important people say important things, when important people say dumb things, or when someone says something unique, or when someone says something uniquely. Quotations from reliable sources adds to the credibility of your post and blog in general.
15. Put it in your own words:  Obviously there will be times when a direct quote is necessary, although, whenever possible, put it in your own words. After all, it is your blog.  
16. Try to be unique:  Try not to simply rehash the news, or what people already read other places.  Rush Limbaugh, to use him as an example again, did not become famous because he repeated what was in the New York Times.  He forms his own opinions, he is creative, and, most important, he is an entertainer.  
17. Rarely write about your self, but do write about yourself:  It's your blog, so people will want to know about you.  If you experience something unique, or there is something unique that makes you a more credible blogger, do share it with your readers. For instance, I am a respiratory therapist who experiences many unique things in the hospital setting.  I also have an interesting asthma history.  At times I share these on my blog. However, blogs that are about you don't get many viewers, mainly because people don't care about you.  Yet people still want to know you. So write about yourself, but do it rarely.  
18. Write about things that matter to you:  This is what makes your blog yours, and what makes it unique, and what makes it interesting.  Generally, if something inspires you, and is written with passion, it will probably generate readers. 
19. Know that not every post will get comments, or will be shared by your readers:  Yet it is all important.  When your content is shared, it will make your blog grow in readership and popularity.  It may even generate some money for you on the side, if you use adsense or other form of ads on your blog (which I highly recommend you do).  
20. Site your sources:  Use references as often as possible.  Cite where you ideas came from. This will help you maintain credibility.  You can either cite your references at the bottom of posts, or you can just link to them here. Both work, although links take up less space.  Now, the problem with links is that most will disappear in time.  So, if you want to make your blog timely, or to provide further reading for your readers, or so you remember exactly where you got your information from, references are necessary.  This is especially important if you are writing about studies, or if you are writing knowledge building articles. 

Further reading: 

1. How to write great blog content
2. 20 tips to writing great blog posts

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What are the parts of a tracheostomy tube?

In 1543, Andreas Vesalius (1514-1564) described how he breathed for a animals by blowing into a reed inserted into their necks through a tracheal opening. This was one of the first descriptions of a tracheostomy tube.  By the 19th century the operation of tracheotomy was perfected, and tracheostomies resembled those used today.

Since we have already discussed the procedure of tracheotomy and the basic indications for them, this post will cover the basics of the tracheostomy tubes themsevles.

1.  What is a tracheostomy tube?  This is a small, hollow tube inserted into a stoma created by a tracheotomy.

2.  What does a tracheostomy tube consist of?  What does it come with?  My humble answer:  Most trachs come with three parts:  Outer cannula, Inner cannula, and obturator.  The outer cannula holds the stoma open and it has neck plates that extend on both sides so it can be secured by a velcro trach collar or trach ties. The inner cannula has a lock to keep it from being coughed out.  It is easily removed so it can be cleaned.  Essentially, the inner cannula makes cleaning easier.  The obturator is used to insert the trach.  It slips into the tube and helps the doctor guide the trach into place.

3.  What is a fenestrated tracheostomy?  What are the benefits and disadvantages of it?  It's a trach with holes or fenestrations in the outer cannula that allow air to pass into the upper airway so the patient can cough to remove secretions and talk.  Basically, it allows normal breathing and the ability to speak. It allows a trial of normal breathing and normal talking before a trach is removed, and may also necessary for long term trachs.  To take advantage of the fenestrations the inner cannula must be removed and the cuff (if there is one) deflated.

4.  What are the different types of tracheostomies?  What trach to use depends on the patient, and trach should be 3/4 the diameter of the patient's trachea.  The following are the types of tracheotomy tubes according to John Hopkins:

• Cuffed with inner cannula:  The inner cannula may be either disposable or reusable.  Cuff should be inflated only for positive pressure breaths.  It must be deflated to use a speaking valve.  
• Cuffless tube with inner cannula:  T'he inner cannula may be either disposable or reusable.  Good trach for people who don't need to be on a ventilator.
• Fenstrated cuffed tracheostomy tube:  This increases the risk for aspiration due to the fenestrations.  The fenestrations also make it difficult to ventilate these patients.  However, good for weaning off trachs and for some patients who want to use a speaking valve. This type of tube is good for long term ventilator patients.
• Fenestrated cuffless tracheostomy tube:  Only used for patients who have difficulty using a speaking valve with the other trach tubes. There are risks associated with using fenestrations, such as aspiration and glanulation formation around the site of the fenestrations
• Metal tracheostomy tubes:  Rarely used.  Cannot use during MRI, and will cause alarm during airport security checks.  

5.  What is an inner cannula?  An inner cannula is a cannula inserted into the trach.  It allows for easy maintenance of the trach especially if there are thick secretions.  It also has a universal adaptor on it so the patient can be connected to a Ambubag or ventilator circuit to receive positive pressure ventilation.  

6.  How can a person with a trach speak?  The patient can speak either if the tube has a speaking valve or if the patient simply covers the opening with a finger.  For this to occur, the outer cuff must be fenestrated.  

7.   What is a tracheostomy cuff? When is it needed and when should it be inflated?  When should it be deflated?   A cuff will irritate the trachea, and therefore should not be used unless needed for positive pressure breaths. It also allows a place for secretions to pool, and therefore increases the risk of micro-aspiration of secretions, increasing the risk for lung infections.  The only reason a cuffed tracheostomy is necessary is when positive pressure breaths are indicated. When a person is receiving positive pressure breaths, whether by AMBU-bag, BiPAP, or mechanical ventilator, it is necessary to inflate the cuff. This is necessary to prevent air from leaking around the tube in order so the patient receives an adequate breath or tidal volume.  If a patient is not receiving positive pressure breaths the cuff, if there is one, should be deflated.  For patients who require positive pressure ventilation, the lowest possible cuff pressure should be used to inflate the cuff, and it should be deflated four times a day to prevent tracheal necrosis

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