It's also a condition very common among post operative patients that can lead to pneumonia, respiratory distress and even respiratory failure if the patient is not managed properly. Likewise, it's a common cause of long hospital stays.
Before I delve into who else is at risk, allow me to define this condition.
Atelectasis: Simply put, it's a condition where regions of the lungs are collapsed or airless.
A more detailed discussion would discuss the reduced functional residual capacity, or shallower breaths than normal. While perfusion stays the same, ventilation to some parts of the lungs is diminished, and this causes ventilation/ perfusion (V/Q) mismatching, and this leads to hypoxemia.
Now we have increased surface tensions holding shut the collapsed alveoli so that higher forces of pressure are needed. More compliant regions of the lung may be prone to over-inflation. This must especially be considered when using procedures such as IPPB, which will be discussed later in this post.
So now we must ask: why, how and who?
We'll start with the who. Who is at greatest risk of developing Atelectasis? Who are we worried about the most?
- Severe asthma
- Cystic Fibrosis
- Interstitial lung disease (pulmonary fibrosis)
- Pulmonary embolism
- Adult Respiratory Distress Syndrome (ARDS)
- Neuromuscular disorders (ALS)
- General anesthesia
- Surgery to abdominal cavity
- Thoracic surgery
- Other surgery
- Pulmonary contusion (trauma)
- High levels of oxygen (greater than 60%)
Thus, there are three general physiological causes for this condition. According to Respiratory Disease: Principles of Patient Care, edited by Robert L. Wilkins and James R. Dexter, 1993, They are:
1. Inadequate Lung expansion
2. Obstruction of the Airway
3. Surfactant Depletion
So now I'll delve into each of these three in more detail:
Inadequate lung expansion: To expand the lungs fully one must be able to take in a deep enough breath to create an inspiratory force, or negative intrapleural pressure, needed to open the lungs, according to Thomas P. Malinowske, author of chapter 13 of Respiratory Disease. "Factors that weaken the respiratory muscles or reduce the effect of normal negative inspiratory pressures will reduce lung inflation and encourage atelectasis."
So who can't take in a deep enough breath? Well, consider the elderly, or the malnourished, or any sick person who is on sedatives or something like Morphine, or any patient with a neuromuscular disorder, such as ALS. All of these patients may have trouble generating the strength to take in a full, healthy deep breath.
General anesthesia and paralysis (paralytics) also fits into this category as, according to Malinowski, anesthesia causes your diaphragm to relax and to become displaced upward. Therefore, long surgeries increase the risk of atelectasis further.
He notes that upper abdominal surgeries are at greatest risk, followed by thoracic, and then followed by any other surgery. Post operative pain diminishes respiratory effort, and this must be controlled with analgesics (pain killers) such as Morphine, yet these medicines may also diminish respiratory effort. So it's sort of a double edged sword.
Malinowski also mentions that topical coolings to the left phrenic nerve during cardiac surgeries can decrease diaphragmatic movement and cause left lower lobe atelectasis.
Post op patients are at risk for developing Atelectasis for 7-14 days.
Obstruction of the airway: Here we have our secretions. Patients with lots of secretions are your respiratory diseases (COPD, severe asthma, CF, smokers). Any condition that diminishes the ability of the patient to expectorate secretions increases the risk for atelectasis. And what makes matters worse is that anesthetics dries out the body, making it even harder to bring up secretions.
Therefore, these patients need to be well hydrated. However, this is often complicated in patients with cardiac issues such as congested heart failure (CHF), which includes your end stage chronic lunger, who often have CHF. In these patient it may be a tricky balancing act between hydrating and diuresing.
When these patients develop mucus plugs, this leads to atelectasis
Surfactant depletion: Surfactant is a soap-like substance that decreases surface tension and makes it easier to open the alveoli. When this is depleted it can cause atelectasis. Conditions that may reduce surfactant are CHF, lung contusions, anesthesia, pulmonary embolism, ARDS, High oxygen levels, and low tidal volumes long term (obesity, long surgeries, etc.). Long cardiac surgeries may also lead poor lung perfusion and "insufficient release of surfactant," according to Malinkowski.
Signs and symptoms depend on the patient, his medical history, how much lung is involved, and how long the patient has had atelectasis. Some patients have some degree of atelectasis long term and show few symptoms, while for other patients the condition may be life threatening.
So, what are the signs and symptoms?
- No symptoms at all (minimal lung involvement)
- Mild dyspnea (minimal lung involvement)
- Severe dyspnea (moderate lung involvement, end stage lung disease)
- Shallow breathing (due to loss of lung compliance
- Tachypnea (a common sign; rate depends on degree of lung involvement; is a method of maintaining adequate gas exchange with lower tidal volumes)
- Tachycardia (May indicate infection due to retention of secretions)
- Fever (May indicate infection due to retention of secretions)
- Late inspiratory crackles (indicate sudden popping open of atelectic regions, often clear after patient takes subsequent breaths)
- Diminished lung sounds (May indicate mucus plus or collapsed airway in affected region and indicates no air movement in that area)
- Accessory muscle usage (indicates increases work of breathing due to loss of lung compliance
1. Quitting smoking: Studies show that quitting smoking 6-8 weeks before surgery reduces the risk of post operative atelectisis. Quitting smoking is also proven to reduce the risk of developing atelectisis overall, especially in patients with COPD. Therefore, it's vital hospitals and physicians talk to their patients about the importance of quitting smoking. I discuss a good smoking cessation program here.
2. Incentive Spirometer: This generally starts before the patient has surgery. Since most upper abdominal and thoracic surgeries have some degree of atelectasis, it's important to educate these patients on the importance of taking in deep breaths after their surgery.
I wrote about how to prevent pneumonia here. Human beings will usually sign 3-4 times every hour as a natural means of exercising the portions of the lungs that are not used with every breath. Yet when the patient is on pain medicine such as morphine, or has had surgery, he's less likely to take these deep breaths. This can lead to atelectasis and pneumonia.
So it's important to teach them about the importance of performing cough and deep breathing exercises post operative, and/ or how to properly use an incentive spirometer (IS).
Cough and deep breathing exercises work great for most patients. This is okay, and it can't hurt the patient, yet it's a cost that is not necessary for most post operative patients. Studies show that simple cough and deep breathing exercises with a good breath hold on a regular basis (like 10 good breaths every hour) works just as well as using an IS -- for most patients.
Yet in the hospital doctors usually do a little overkill and simply order incentive spirometers for all post operative patients. Writing the IS order is generally a habit of surgeons, or is simply a part of the post operative (or pre operative) admitting orders.
Ordering an IS on every patient is not a bad thing. For one thing, it gets the RT in the patient's room to give a full assessment and a good teaching. For another, having the IS on the bedside table acts as a reminder to the RN, DR, RT, patient and patient's family of the importance of taking deep breaths.
Studies show, however, that encouraging the patient to cough and deep breathe (C&DB) with good breath hold 3-10 times every hour is usually enough to prevent post operative atelectasis.
Likewise, based on my own experience, I have NEVER had a patient who was not able to perform C&DB exercises, yet I do find many patients who are unable to adequately perform an IS procedure.
I find that if medical practitioners over rely on the IS, and think that just because the patient is putting the mouthpiece to her lips is going to prevent atelectasis, this is far worse than doing nothing at all. It's important to see the IS used correctly, yet it's even more important to see chest rise. It's also important, if possible, to see a breath hold.
If a patient can do an IS properly, great. Most patients can. Yet if you don't see proper use, like proper chest rise, don't be afraid to work with the patient on C&DB exercises and to skip the IS. At least for the time being. That's my professional opinion.
2. CPAP (BiPAP): This may be needed for those patients who are unable to take in a deep breath, or who are not conscious enough, or who have an underlying respiratory complication such as COPD, and who are having trouble oxygenating and ventilating due to atelectasis.
The CPAP (PEEP or IPAP) provided is effective in popping open the lungs and keeping them open slightly so that they are easier to get open with subsequent breaths. This is also an effective means of improving oxygenation.
IPPB: Intermittent Positive Pressure Breathing 3-4 times a day for 5-10 minutes has historically been ordered on the patient's who are just not able to take deep breaths on their own, or to do so effectively. This is based on the same principle of CPAP in that it is believed to pop open collapsed alveoli. It's believed to improve lung volumes and help the patient produce an effective cough. It's rarely used anymore, and it's efficacy is always in question. IPPB is rarely ordered by Shoreline physicians.
PEP therapy: A very inexpensive method of helping the patient exercise the lungs, improve lung capacity and secretion clearance. We do not use PEP therapy at Shoreline Medical due to cost and inability to bill for it.
CPT: Chest physiotherapy is generally used when the patient has retained secretions that he is unable to remove on his own, such as your chronic lung patients. However, where I work, CPT is ordered on all post operative patients. This is done to improve lung inflation and enhance secretion clearance. Again, studies show mixed results as to whether or not this is actually effective. We have one doctor who orders CPT on all his post op patients.
Bronchodilators: Believed to generate a better cough and enhance secretion clearance. While studies do show that bronchodilators may increase sputum clearance, other studies show this effect is minimal and does not benefit the patient to the degree many physicians would want. Likewise, a bronchodilator will not further dilate airways that are already dilated. Yet we still see this routinely ordered by some doctors on all their post op patients.
Allaying the myths
Many of the procedures used to treat and prevent atelectasis are not scientifically proven to be of any use to the patient. These procedures are ordered because there is a belief that they must work.
CPT is often ordered for this reason. Yet, according to PubMed, "Treatment of atelectasis: where is the evidence?, by Margrid B Schindler, there is no real evidence that it really does any good. Only two studies showed it was effective, while other studies showed it was not effective or no better than doing nothing.
Bronchodilators are often used to treat post operative atelectasis, yet there is no evidence they do any good. It is my belief, along with common sense, that bronchodilators will help with any patient who has bronchospasm because it will enlarge the airway and make it easier to expectorate otherwise trapped secretions.
Yet for most patients, CPT and bronchodilators are not indicated, yet often ordered or at least often recommended by the experts.
However, it is one of the common beliefs by the medical community, even though the ultimate goal is to reduce costs, that overkill is better than under kill. That it's better to order too much for the post operative patient than to order too little. It's good to have the RT and RN both in the patients room often to remind the patient of the importance of taking deep breaths, and to assess the patient.
Some studies show that PEP, CPAP and IPAP therapy does work as intended, yet these results are based on only a few studies. There is no conclusive evidence.
So the best way to treat post operative patients is still up in the air, although many hospitals are moving toward RT consults, or RT Driven protocols. These allow the RT the right to adjust treatment according to the specific needs of the patient.
And until further studies are done to provide evidence that one thing works better than another, treatment and prevention of this condition will vary from institution to institution and from doctor to doctor.