Lower airway respiratory problems – July 2015
Many airway problems are located in the upper part, particularly at the back of the throat. However beyond the vocal cords into the middle and lower airways a number of other breathing difficulties can be encountered. The pre-hospital responder requires some ability to recognise and understand many of these diseases.
The diseases discussed here are not exhaustive of all breathing problems. These are the most commonly encountered pre-hospital causes of breathing difficulty. Many people with these diseases will manage themselves at home. First responders will be called for acute presentations of these problems not able to be managed. Transport to hospital should be expected in most cases.
The middle airways are large tubes for moving air. They include the trachea and the bronchi. They do not cause many respiratory diseases. The most notable is bronchitis where these tubes become inflamed reducing diameter and increasing mucous production. Bronchitis can be acute or chronic. The latter may be problematic for months at a time and recur over years. It is typically caused by smoking or exposure to chemical irritants. Bronchitis is one of the chronic obstructive pulmonary diseases (COPD). Inflammation produces breathing difficulty and productive coughing. The difficulty getting air past the swelling means the lungs do not get enough air causing the patient to often look quite cyanosed.
The lower airway, in contrast, is the site of significant respiratory disease. The two key problem sites include the bronchioles and the alveoli that attach to them. Despite their proximity disease of each produces quite different problems.
The bronchioles are very small and, because they are made of muscle, are capable of narrowing (spasm). The immune system causes this to happen as a protective mechanism to keep allergens out. Asthma and anaphylaxis are two examples of disease of the lower airway. The narrowing or ‘bronchoconstriction’ is accompanied by swelling (oedema) of the bronchioles and increased mucous secretion. Both are excessive immune responses that have triggers that cause them to happen and are reversible if correctly treated.
Treating bronchiole disease is about turning off the unwanted response including the immune system and/or the constriction actions. Adrenaline is administered for anaphylaxis and works partly as a bronchodilator to reopen the bronchioles. It helps stabilise the MAST cells part of the immune response that is causing the problem in the first place. Medical steroids can be added to further help reduce the immune system activities.
Salbutamol is typically administered as the first line bronchodilator for asthma. It is used by patients for self administration and by first responders to provide emergency treatment. This is a quick acting ‘reliever’ that reopens bronchiole narrowing in a similar way adrenaline does. It acts only on the lungs without the unwanted heart and blood pressure actions adrenaline has. There are short acting and long acting forms of these drugs and come in forms including hand held spray puffers and for use in nebulisers. There are others such as atrovent that do the same thing only via different ways.
Either problem can cause breathing difficulty. There are several key features in recognising bronchiole disease. Wheezing is a whistling sound that can be heard as air passes through narrowed bronchioles. When severe there may be so little air coming into the lungs that no sounds can be heard. It is important when assessing the asthma patient that the absence of breathing sounds is not always a good thing. What is able to be heard must be compared to the overall presentation of the patient. Wheezing may be heard by simply being close to the patient but is best heard using a stethoscope.
There are muscles to draw air into the lungs but few to push it back out again. Breathing out is meant to be a relaxed and passive part of breathing. This causes two observable effects in bronchiole disease. Air has trouble getting past the bronchospasm and into the alveoli. The pressure sucking air into the lungs causes the softer part of the chest wall, the intercostal, clavicle and diaphragm muscles to be sucked inward instead. This is known as retraction and is always a significant physical finding.
Once inside the lungs though the air in the alveoli becomes trapped and is difficult to push back out. Passive flow alone isn’t enough and use of the few expiratory muscles is necessary. Expiration is forced and takes longer than normal – a prolonged expiratory phase. It also means the work of breathing is increased making those muscles and the patient very tired.
History is very important with the patient with bronchospasm. The anaphylactic patient may have a history of exposure to allergens. The asthmatic may have had previous episodes or have required hospital or intensive care admission. In both cases diagnosis may be known.
In both cases the time frame since onset is important in helping identify how long the patient has been battling the problem. Longer onset times mean the illness is more estab. The patient is likely to be tireder. However quicker onset times mean the illness is overwhelming the patient at a more alarming rate and there may be less time to react. It is also important to establish if the patient has taken any of their own medication already and if that has been helpful. Many people with these diseases have personal plans for responding to problems.
Narrowing of the bronchioles (bronchospasm) is a main feature of asthma and sometimes anaphylaxis. It is characterised by wheezing, chest muscle retraction and prolonged expiratory phase. It is reversible with a bronchodilator such as salbutamol or adrenaline.
Alveoli disease include those that damage the alveoli such as emphysema and those that occur within them but can be removed with correct treatment. The latter include pneumonia and acute pulmonary oedema.
Emphysema is a common alveoli disease. Associated with smoking, emphysema involves alveoli destruction. The amount of alveoli available for gas exchange is reduced. The amount of oxygen that can diffuse into the blood and carbon dioxide removed is reduced. The patient develops chronic change in the amounts of these gases that circulate in the blood. High carbon dioxide stops being responsible for triggering breathing in severe emphysema and low oxygen becomes more important.
The lack of oxygen in the blood means that the emphysema patient has little or no tolerance for exercise. Even going to the toilet may cause severe breathing difficulty. This is very important for pre-hospital responders to recognise. Any increased exertion can make the patient’s presentation far worse and the respiratory distress more severe. Even asking the patient to stand and transfer to a wheel chair or stretcher can be too exhaustive. Great consideration must be applied to the logistics of moving such patients.
Emphysema is one of the diseases bundled as chronic obstructive pulmonary disease (COPD). Presentation for COPD can look similar to bronchiole lower airway disease. There may be wheezing. Mucous production is greater and productive coughing common. Typically these patients have wasted muscles and often barrel chests caused by constant pressure from the air trapped in the alveoli. They often have supplementary oxygen systems in their home. Some of the elements may be reversible (such as bronchospasm or infection) but essentially the alveoli damage is permanent.
Oxygen administration to the patient with emphysema (and bronchitis) is important but it is possible to administer too much or inappropriately. Provide just enough oxygen flow for the acute need. This might be a nasal cannula or oxygen mask. Many patients with emphysema will have their own oxygen supply at home. What the patient normally uses at home can be a guide and they may even prefer to continue to use their own device. A nasal cannula will be commonly used for this kept at low flow rates of 2 – 3 litres per minute. The patient may use this occasionally during the day or may require it almost continuously. If breathing difficulty is tolerable for the patient then they may be permitted to remain on whatever oxygen supply they usually require.
Where the breathing difficulty is too severe the oxygen delivery can be increased by changing over to an oxygen mask with a higher flow rate. Salbutamol therapy may help with any wheezing heard. However this is alveoli damage and not bronchiole so it may not help much. If the patient is having difficulty breathing and has a wheeze then administer nebulised salbutamol. If the patient does not have a wheeze then oxygen therapy without salbutamol may be preferred. Where there is doubt an initial therapy of salbutamol can be considered. Specific local guidelines and protocols should always be followed. Previously used nebuliser masks may no longer be effective and changing to a new mask a better idea.
Infection in the lower airway is common, particularly amongst the elderly. It is characterised by productive coughing, fever, sometimes rigours and varying level of breathing difficulty. Lung sounds can include crackles in the affected fields. The patient may be taking antibiotics for their infection.
Severe infection in the lungs is pneumonia. Patients with pneumonia not only have breathing difficulty but also severe infection. They may be lethargic and generally unwell. Gas exchange in the alveoli may be impaired. Sitting the patient upright will be important as will be the addition of high flow oxygen therapy.
Infection may last for days to weeks. Patients often have disturbed sleep from breathing difficulty. The continued increased work of breathing tires the muscles of breathing. That a patient has been sick for several days is not reassuring. They may well be nearing the end of their ability to cope and continue.
There is no particular role for pre-hospital first responders for managing the patient with acute or severe chest infection. However recognition of the severity of illness, not subjecting the patient to exertion and ensuring access to an appropriate level of medical care occurs is all important.
Crackles are a common sound during infection. They are also heard with acute pulmonary oedema (APO). This causes breathing difficulty even though it is actually caused by the heart. If the heart does not beat effectively enough pressure can build up behind the heart and in the capillaries in the lungs. If severe enough this pressure can force fluid all the way across into the alveoli. When this occurs it is called pulmonary oedema – that is, fluid in the alveoli of the lungs. Like pneumonia, the fluid in the alveoli interferes with gas exchange making it particularly difficult for oxygen to be into the blood. Patients often refer to past episodes as ‘fluid on the lungs’.
APO presents with varying breathing difficulty. It commonly occurs at night when lying down causes extra blood to return to the heart. This increases the workload of the heart and increases the congestion forming in the lungs. Patients will want to sit upright and will often note that they sleep on several pillows to help with breathing. It is likely the patient will be found to have a history of heart problems and perhaps previous APO or ‘fluid on the lungs’ episodes. The patient may complain of chest pains at the same time.
Patients with APO are managed in an upright posture and administration of high flow oxygen. The upright position helps to reduce the blood returning back to the heart and so reduces the congestion. Chest pain is managed as would be any other patient. As the pain is likely to sound cardiac, then GTN therapy is likely.
One final cause of breathing difficulty is hyperventilation. This is simply breathing faster and deeper than normal without any illness causing it to happen. Too much oxygen is taken in but that isn’t really a problem. Too much carbon dioxide is breathed out. This causes patients to feel dizzy, light headed and sometimes have the hands spasm (tetany). This isn’t a medical emergency and is usually associated with anxiety or emotion. If in any doubt, always treat the patient as if they have a more serious cause for breathing difficulty. Hyperventilation does not need any treatment other than to reassure the patient and have them control their breathing. Oxygen therapy does not help and re-breathing into a paper bag is no longer used. Having the patient rebreathe into a paper bag if there is a serious problem could be life threatening.
Jeff Kenneally www.prehemt.com
Jeff is the author of the 2014 – 2016 Ambulance Victoria First Responder clinical practice protocols and accompanying education program.