How do we manage breathing problems in ALS? (links)
 
What happens normally when you breathe?
How do we check respiratory muscle strength?
What are the symptoms/signs of respiratory failure?
What is the treatment for breathing problems in ALS?
What are some of the general measures for good respiratory care?
General assessment
Treat acute infections
Management of secretions
Treatment of progressive swallowing difficulties: Prevention of aspiration and PEG placement
Acute respiratory failure: short term mechanical ventilation
Long Term Management with Noninvasive (no tube in the mouth or throat, no tracheostomy) ventilation
Use of noninvasive ventilation in ALS
Invasive ventilation
Withdrawal of Care
 
What happens normally when you breathe?
Normally your lungs function to allow you to breath in air (oxygen) and exchange it for carbon dioxide, a waste product of metabolism in the body. This exchange takes place in the air sacs called alveoli. During inspiration, which is an active process, air is drawn into the mouth, down the large airway called the trachea and then into the bronchi and finally into the smaller airways (bronchioles) to the air sacs (alveoli). (Figure 1) The exchange of oxygen and carbon dioxide takes place in the air sacs or alveoli and carbon dioxide is then expired out of the lungs through the passive process of expiration. The diaphragm and chest muscles (called intercostals) are responsible for inspiration and the abdominal muscles and other chest muscles (the internal intercostals) help with expiration (Figure 2).
 

Alveoli or air sacs

Figure 1: Respiratory System The function of the respiratory system is to exchange oxygen in the air we breathe for carbon dioxide in the blood that builds up from body metabolism. This exchange takes place in the alveoli or air sacs.
 

Figure 2: Muscles of respiration.

 
In ALS, there are several problems that cause difficulties in breathing. First as the respiratory muscles weaken, oxygen cannot be adequately exchanged and carbon dioxide builds up in the blood stream. This leads to sleepiness and fatigue. Furthermore, since the respiratory muscles are weak, there is a decrease in the strength of the cough. The poor cough and a decrease in gag reflex leads to problems clearing the airway and keeping it clear of secretions and oral contents. As swallowing difficulties progress, increasing oral secretions result. These secretions can get into the airways and alveoli blocking adequate exchange of oxygen. The decrease in effective coughing further compromises the ability to clear these secretions. Finally, if the muscles in the back of the throat are weakened, the airway is unprotected during swallowing. This leads to aspiration in which the contents of the oral cavity can enter the airways. Aspiration can lead to infection (aspiration pneumonia) as well further compromise of carbon dioxide exchange. Furthermore, with increased swallowing difficulties, oral food intake is reduced and malnutrition occurs. Malnutrition leads to further compromise by increasing overall muscle weakness including the respiratory muscles.
 
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How do we check respiratory muscle strength?
 
Respiratory function can be assessed by asking about symptoms that indicate weakness and failure of the respiratory muscles to exchange oxygen and carbon dioxide (see the next section) and by the measurement of respiratory functions with the spirometer. The amount of air that your lung can hold is the vital capacity (VC). In addition we can check the strength of the respiratory muscles. The MVV or minute ventilatory volume is measured by having a person breath deeply in and out for a minute and measuring the volume of air that was taken in and out. This measures both overall strength and endurance of breathing. We can also measure the strength of the muscles as they breath in (i.e. inspiratory pressure) with several different maneuvers through the mouth (maximal inspiratory pressure or MIP, also the negative inspiratory pressure or NIF) as well as the nose (called the sniff nasal pressure, SNP). Expiratory muscle strength is the pressure that is exhaled through the mouth (maximal expiratory force or MEF). Most centers measure the vital capacity at baseline and with each visit. As the vital capacity decreases or symptoms occur, measurement of the oxygen and carbon dioxide levels in arterial blood can be carried out. Furthermore, as the level of the vital capacity drops to half of normal (50%) consideration to initiation of NIPPV should be given (See section entitled “How are ventilators used in treatment of respiratory problems?)
 
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What are the symptoms/signs of respiratory failure?
 
The symptoms of respiratory failure include: shortness of breath on exertion or at rest, fatigue, inability to sleep flat, problems with sleep, daytime sleepiness, and morning headaches. Examination may show rapid breathing, the use of extra muscles to help breath, speaking with a low volume when talking, and an ineffective cough. If aspiration is also a problem there may be coughing with eating, watery eyes, sneezing, alterations in breathing, changes in the lung sounds, gagging, frequent throat clearing, swallowing more than once for each bite or sip, and even a gurgly sound to the voice.
 
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What is the treatment for breathing problems in ALS?
 
Table 1 presents the important considerations in the respiratory management of people with ALS. A review of the treatments are covered in the sections below.
 
Table 1: Considerations in the management of respiratory complications of ALS
 
• Pneumovac and Flu vaccine
• Gastrostomy placement to maintain adequate nutrition
• Control secretions
• Aspiration (Food or secretions down the windpipe)
• Treat any underlying medical conditions and acute infections
• Identify and treat respiratory failure
• Withdrawal of care
 
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What are some of the general measures for good respiratory care?
 
General assessment
 
First a baseline examination and assessment of the breathing tests described above should be performed. Other medical conditions that might contribute to respiratory problems need to be identified and treated. For example, asthma, COPD, and congestive heart failure are common and should be optimized with specific therapy. Risk factors, such as cigarette smoking, secondhand smoke, dusts and fumes, and exposure to people with acute viral respiratory illness, should be identified and avoided. Pneumovax immunization and yearly influenza immunizations are advised.
 
In follow-up, breathing tests should be done along with the lung exam at every visit to help the doctor identify any problems that are arising. This will allow early intervention and treatment of respiratory problems.
 
Treat acute infections
 
Since acute respiratory infections can precipitate respiratory failure (i.e. the need to be on a mechanical ventilator) in the already compromised ALS patient, these infections must be treated aggressively. The additional secretions combined with an ineffective cough and reduced strength of the muscles that breathe in and out leads to increased airway obstruction with secretions and collapse of the airways with further reduction in the exchange of carbon dioxide and oxygen. This further elevates the levels of carbon dioxide. Thus, ALS patients with an upper respiratory infection may require hospitalization at a lower threshold for intravenous hydration, antibiotics and aggressive secretion management and pulmonary toileting as described in the section on management of secretions.
 
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Management of secretions
 
Secretion management is an important part of pulmonary care in ALS since secretions can lead to plugging of the airways, collapse of the air sacs, and infections secondary to aspiration. These all result in decreased carbon dioxide clearance (resulting in increased levels of carbon dioxide in the blood) and decreased ability to get oxygen into the lungs (resulting in lower oxygen levels or hypoxemia in the blood). Treatments are directed both at decreasing and thinning the secretions as well as increasing clearance. Medicines that decrease secretions include: Anticholinergic medications (Glycopyrrolate, Robinul), amitriptyline (elavil), transderm scopolamine, levsin or hyoscyamine, and botulinum toxin injection into the salivary gland. If these modalities fail, irradiation of the parotid gland can be helpful. If the secretions are thickened, especially with use of anticholinergic agents, hydration, guaifenesin, propranolol and acetylcysteine nebulizing treatments can be considered.
 
As the cough weakens, it may be too weak to maintain clear airways. At this point a program to optimize secretion mobilization and clearance should be initiated. Interventions that facilitate the clearance of secretions consist of air stacking assisted cough either manually or mechanically through an insufflator-exsufflator (coughalator). In order to loosen secretions to be mobilized, percussing (pounding) on the back in different positions (postural drainage and pulmonary toilet) can be carried out. This is done with care since the secretions can block the airway as they are loosened and move in the air passages of the lung. Alternatively, a vest (high frequency wall oscillations) can be used to loosen secretions. If the cough is weakened, an inexsuffalator or coughalator can be used as an assist device to help bring the secretions up. If necessary, a suction machine can be used to clear the mouth when the secretions are brought up Using an incentive spirometer at home may help prevent airway collapse. The use of a medicine called theophylline may improve diaphragmatic function and cough.
 
Oxygen may be used at home to treat low levels of oxygen (hypoxemia) measured by either a blood gas or oximetry. However since oxygen can aggravate increased carbon dioxide and thus increase the rates of pneumonia and hospitalizations, it should be used only with extreme care. The oxygen flow rate is adjusted to achieve an oxygen saturation in the blood of > 95 percent.
 
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Treatment of progressive swallowing difficulties: Prevention of aspiration and PEG placement
 
Careful attention to swallowing and feeding is also important and aggressive management should be initiated to avoid aspiration and weight loss. If swallowing problems (dysphagia) are present, the speech language pathologist will educate the person living with ALS about the appropriate food consistency and proper swallow technique to use. In addition the patient should sleep with his head elevated and never lay flat following meals. As swallowing difficulties worsen or the vital capacity drops below 50%, a percutaneous gastrostomy (PEG) tube will be recommended to maintain nutrition. This is a small tube inserted into the stomach during endoscopy and requires sedation without general anesthesia. While the PEG tube will improve nutrition and reduce risk of aspiration it does not fully prevent aspiration. Early intervention with PEG tube can prolong survival from 2-4 months.
 
Acute respiratory failure: short term mechanical ventilation
 
Acute (sudden or very rapid) respiratory failure may occur during a pneumonia or other illness that weakens muscles or increases secretions. If the underlying cause of the worsening can be treated the patient may return to his/her baseline function. In this case, temporary ventilator support can be given using noninvasive ventilation (NIPPV-see below) or by endotracheal intubation (putting a tube into the nose or mouth that extends into the windpipe). Some ALS patients can recover from acute respiratory failure and regain fully independent breathing for a considerable period of time; this may happen repeatedly before it is necessary to consider long-term mechanical ventilation (tracheostomy with ventilator). Alternatively, there may be a period of time when mechanical ventilation is needed for only part of the twenty-four hours, such as during sleep, allowing considerable “free time” off the ventilator during the day.
 
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Long Term Management with Noninvasive (no tube in the mouth or throat, no tracheostomy) ventilation.
 
Use of noninvasive ventilation in ALS
 
As the deterioration of muscle strength and respiratory function caused by ALS progresses, the need for ventilatory assistance should be considered. In recent years, nocturnal noninvasive positive-pressure ventilation (NIPPV) has become the treatment of choice for patients with chronic respiratory insufficiency due to ALS. The noninvasive ventilator is triggered by the patient’s own breathing and reduces the work of breathing, improves exchange of carbon dioxide and oxygen, and improves sleep quality. Furthermore it has been shown to prolong survival as well as improve the quality of life in people with ALS who are able to use it regularly. A study at Hahnemann University (now Drexel University) examined NIPPV use in 122 patients. There was a statistically significant improvement in survival from initiation of NIPPV in patients who used NIPPV for more than four hours a night (14.2 months) compared to people who did not use the intervention (4.6 months, p < 0.001). Other beneficial effects of NIPPV in patients with ALS include improvements in quality of life and cognitive (thinking) function. This includes measures of fatigue.
 
Presently the accepted recommendation for starting NIPPV is an FVC (forced vital capacity test) of 50% expected or symptoms of respiratory failure (shortness of breath, daytime sleepiness, etc).
 
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Invasive ventilation
 
As ALS progresses, the person living with the disease may become increasingly dependent on ventilation and ultimately, will require invasive ventilation with a tracheostomy (tube placement into the main breathing pathway, the trachea, through the neck.) This will provide more efficient ventilation and better control of the upper airway and secretions. The decision to proceed with tracheostomy and invasive ventilation is often difficult and is highly individual. If ventilation is being considered, it requires an educational process that includes the patient, family, and healthcare professionals with frequent decision modifications. Long-term ventilator assistance is elected in advance by only a small minority of people with ALS (10% of the people with ALS at the MDA/ALS Center of Hope at Drexel University). In making the decision, the person living with ALS must consider his,family support, level of independence, insurance coverage, and financial resources. The choice of a home ventilation program requires supportive families and 24 hour a day supervision by family members and nursing. The cost of invasive ventilation has been estimated at $153,252- $336,852 per year, most of which is the cost of home nursing. While few people living with ALS chose invasive ventilation and a home program, 90% of those people who are cared for at home were glad they chose to be ventilated and would choose to be ventilated again while 72% of those patients who were in nursing homes would make the same choice.
 
Withdrawal of Care
 
If a person who is on a ventilator program decides that he would like to terminate ventilatory support, a careful and thoughtful approach is necessary. First there needs to be a complete discussion of the decision to terminate care and the ramifications. Counseling to assure that the person understands the decision and treatment of depression is important. Once the decision is finalized, palliative care and sedation should be initiated as the ventilator is titrated off. Comfort care should be attended to by the physician throughout the process.
 
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