Managing Shortness of Breath. Self Learn series 15

How to manage shortness of breath at home.

Shortness of breath is defined as labored or difficult breathing associated with a variety of disorders, indicating inadequate ventilation or low blood oxygen. Before we proceed to learn how to manage this stressful situation we will review how the normal healthy respiratory system works.

Illustration 1. Positioning of head and neck to maintain a clear airway.

Shortness of breath is also called “Dyspnoea” in medical / nursing terminology. (Latin dyspnoea, Greek dyspnoia from dyspnoos – short of breath) or shortness of breath (SOB) is perceived and/or real difficulty during breathing. This includes the presence of pain on breathing, for example when a patient has pleuresy. It is an extremely common symptom of many disorders, including emphysema, COPD, broken ribs, lung cancer, malignant hypertension, and so forth.

This article is written for ordinary people, without a medical background and includes suggestions on how to cope with shortness of breath. Many of the home interventions, like positioning the patient right do not require a prescription but medications like diuretics and broncho dilators require a prescription from a medical prectitioner in most countries.

Picture 1. Cross-section of the Brain showing the location of the breathing centre in the medulla oblongata of the hind brain.

The desire to breathe, in most of us comes from the Respiratory Centre located in the brain. The process is unconscious and is affected by drugs, eg anaesthesia, exercise, shifts of body fluids and shifts in the levels of carbon dioxide. There are three main components which control respiration. These are: a. The Respiratory centre or controlling area in the brain, b. an afferent pathway and c. an efferent pathway.

The neurones (nerve cells) of the controlling area integrate the information from other parts of the body and produce a coordinated response. This response from the central controlling area is carried to the various organs and muscles along efferent pathways. The input to the central controlling area is from the various sensors via the afferent pathways.

The central controlling area for breathing, called the respiratory centre, is in the lower part of the brain stem, in the medulla oblongata. There are “inspiratory neurones” which are active during inspiration and inactive during expiration. Other neurones are active during expiration but not inspiration-the “expiratory neurones”. These two groups of neurones automatically maintain a rhythmic cycling pattern of inspiration and expiration. This automatic rhythm can be modified by the afferent information eg exercise and certain chemicals in the brain.

1. Afferent Nerve Supply: Central Chemorreceptors. Please see picture 2
   Chemoreceptors are cell which are sensitive to chemical stimuli. Thes are located on the floor of the fourth ventricle (part of the brain stem) that respond to the acidity of the cerebrospinal fluid (CSF) and the output from these cells influences breathing. An acidic CSF causes hyperventilation this is the reason for dyspnoea with conditions such as diabetic ketoacidosis. An alkaline CSF inhibits the respiratory centre. Carbon dioxide in the blood can rapidly diffuse across into the CSF, and there is a balance between the level of carbon dioxide, hydrogen ion and bicarbonate ion in the CSF. If the carbon dioxide in the blood increases (eg following exercise), then the carbon dioxide, hydrogen ion and bicarbonate ion concentrations increase correspondingly in the CSF. This increase in CSF acidity causes hyperventilation which lowers the carbon dioxide concentration in the blood. A low blood carbon dioxide level (hypocarbia) has the opposite effect and may occur, for example, following controlled ventilation during anaesthesia. This may delay the return of spontaneous breathing at the end of surgery.
2. Afferent Nerve Supply: Peripheral chemoreceptors. These are located in the carotid and aortic bodies. They are small pieces of tissue that contain chemoreceptors which respond to the oxygen and carbon dioxide concentrations in arterial blood. The carotid body is the more important of the two and is situated at the division of the common carotid artery into the external and internal carotid arteries in the neck. The aortic body is found on the aortic arch. The information from the carotid body is carried along the glossopharyngeal nerve (the ninth cranial nerve) and the information from the aortic body is along the vagus nerve (the tenth cranial nerve), to the respiratory centre. The output from the carotid body is thought to provide information to allow immediate regulation of breathing, breath by breath, by the respiratory centre. In normal people, if the arterial blood reaching the carotid body has a partial pressure of oxygen of 10kPa (80mmHg) or a carbon dioxide partial pressure of more than approximately 5kPa, (40mmHg), then there is an immediate and marked increase in breathing. These limits can be modified by disease or age; for example, people with chronic bronchitis may tolerate an increased concentration of carbon dioxide or a decreased concentration of oxygen in the blood or both.
3. Afferent Nerve Supply: Brain. Breathing can be influenced by other parts of the brain. We can all consciously breathe deeply and more rapidly (called hyperventilation), and this can happen, for example, before starting strenuous exercise. Intensely emotional situations, for example, distressing sights, will also cause hyperventilation. Hyperventilation is also part of the response to massive blood loss. This response is co-ordinated by the autonomic system in the hypothalamus and the vasomotor centre in the brain stem.



Picture 2. Cross section of the brain showing the Afferent nerve (pathway to the brain).

4. Afferent Nerve Supply: Lung. There are various receptors in the lung which modulate the patient’s breathing. Receptors in the wall of the bronchi respond to irritant substances and cause coughing, breath holding and sneezing. In the elastic tissues of the lung and the chest wall are receptors that respond to stretch. There are stretch responses that occur when the lung and chest wall are distended and inhibit further inspiration. This is an obvious safety mechanism to avoid overdistension. Conversely, when the lung volume is low, then there are opposite reflexes. A small increase in lung size may stimulate stretch receptors to cause further inspiration. This can sometimes be seen in anaesthetised patients who have been given an opioid; spontaneous breathing may be absent or very slow, but if the patient is given a small positive pressure breath by the anaesthetist, then inspiration is stimulated and the patient takes a deep breath. This reflex may also have some function in newborn babies just after delivery, when small breaths may stimulate further inspiration.
   There are also stretch receptors in the blood vessels in the lung. If these are stretched, as in heart failure, the response is to hyperventilate. The information from these receptors in the lung is carried to the respiratory centre along the vagus nerve.

The Efferent Nerve Supply (See picture 3, please)

The efferent nerves from the medulla oblongata, more specifically the respiratory, centre pass down the spinal cord to the diaphragm, intercostal muscles and accessory muscles of inspiration in the neck. The diaphragm is supplied by the phrenic nerve that is formed in the neck from the spinal nerves, C3, 4 and 5. The intercostal muscles are supplied by the segmental intercostal nerves that leave the spinal cord between TI and TI2. The accessory muscles in the neck are supplied from the cervical plexus. During normal breathing, inspiration is an active muscular process. Expiration is passive and relies on the natural elasticity of the tissues to deflate the lung. The most important muscle for inspiration is the diaphragm. Any disease that affects the efferent pathways from the respiratory centre to C3, 4 and 5 and then the phrenic nerve to the diaphragm, may cause severe difficulty in breathing. Trauma to the cervical cord, above C3, is normally fatal for this reason.

Anaesthetic drugs and respiration.

Opioid drugs, such as morphine or fentanyl, depress the respiratory centre’s response to hypercarbia. These effects can be reversed by naloxone. Volatile anaesthetic agents depress the respiratory centre in a similar fashion, although ether has less effect on respiration than the other agents. Volatile agents also alter the pattern of blood flow in the lungs, resulting in increased ventilation/perfusion mismatch and decreasing the efficiency of oxygenation. Nitrous oxide has only minor effects on respiration.

The depressant effects of opioids and volatile agents are additive and close monitoring of respiration is necessary when they are combined. When oxygen is not available respiration should always be supported during anaesthesia.

Picture 3. Cross section of the brain showing the Efferent nerve pathway (from the brain).

Now we have a close to full understanding of how normal breathing is regulated. So let us now look at the causes of shortness of breath in relation to the breathing centre, the circulatory system and the musculoskeletal systems.

Causes of Shortness of breath.

Shortness of breath is caused by many conditions affecting either the breathing passages and lungs or the heart or blood vessels. However, the causes can be subdivided into simple categories which are simpler to understand. Doctors further classify SOB as either occurring at rest or being associated with activity or exercise, ie stress related. They will also want to know if the dyspnoea occurs gradually or all of a sudden. Each of these symptoms helps to detect the precise cause of the shortness of breath and will help us to manage the particular patient whom we are trying to understand.

An average 150 pound (70 kilogram) adult will breath at an average rate of 14 breaths per minute at rest. Excessively rapid breathing is referred to as hyperventilation. Many conditions cause shortness of breath. This article is about the most common causes of SOB and is not an exhaustive list.

Picture 4. Diagram of lung, trachea and alveoli. Any disorder which affects these tissues will result in shortness of breath.

Being a little short of breath, after exertion, is entirely natural and harmless. It is actually good for you. The shortness of breath simply reflects the increased oxygen demand that you’ve placed on your body. But there’s a difference between a brisk walk around the block and walking upstairs.

If you pant at the top of the stairs, it could simply mean that you’re unfit, again it depends upon the length of the flight of steps. If you are short of breath after a few short steps you are not well and should seek a medical opinion.

A person could be short of breath because of any number of lung problems. Any lung infection—from a mild cold or case of bronchitis to pneumonia and tuberculosis—can turn breathing into a major challenge.

Three chronic respiratory diseases—asthma, chronic bronchitis and emphysema—all cause shortness of breath and frequently, wheezing. The wheezing is often audible from a distance and without the aid of a stethoscope.

A collapsed lung (hemothorax or pneumothorax) can be problem in people with chest injury/chest infection.

In several serious neurologic conditions—multiple sclerosis, Lou Gehrig’s disease and myasthenia gravis—a person gradually loses the ability to breathe because of progressive muscle weakening. This produces the symptom of shortness of breath.

There are also a couple of emergency situations that can produce sudden, severe shortness of breath. Botulism, lead and food poisoning block messages from the nervous system to the breathing muscles, leaving a person unable to breathe more deeply even though they feel it is necessary.

Providing Symptom relief.

Relief for shortness of breath involves helping the patient get the most use of his/her available lung capacity with exercises, drugs or surgery. Asthma and most infectious lung conditions are reversible. They are treatable to some extent. Here are a few things you should be aware of.

Cigar and Cigarette smoking causes many of the conditions that lead to shortness of breath. It goes without saying, that it would be best not to smoke. You can save money and time by not smoking. Your physician would be pleased to help you quit.

Be fit to breathe. If you’re overweight or sedentary, all you may need to eliminate your shortness of breath is a fitness program to get your heart and lungs in better condition, Brisk walking is a good choice, once you have been cleared medically. Young individuals should aim to walk for 20 the thirty minutes per day.

Breathe from your belly. Abdominal breathing with your diaphragm uses more lung capacity more efficiently, enabling you to breathe deeply instead of rapidly. Inhale through your nose and allow your stomach, not your upper chest, to move outward. That permits air to reach to the bottoms of your lungs, filling them completely.

Kiss the air. People with cardiopulmonary problems can breathe better if they exhale through pursed lips. Nurses, assessing patients should make a note of the fact that patient was pursing his/her lips. Just pucker up after inhaling and slowly let the air out from your mouth, not your nose.

Do physical exercises to increase the strength of your diaphragm and other muscles used in breathing with the help of a resister—a device that is available through either your doctor or medical supply stores. These are called incentive respirometers and several are on the market. You perform several sets of breathing exercises through the resister every day. In succeeding weeks, you increase the resistance, which forces your diaphragm and other breathing muscles to work harder. That increases the strength of your diaphragm, and you may be able to breathe more powerfully. These are used for rehabilitation in most Hospitals.

Inhale before you exercise. Even if strenuous exercise causes exercise-induced asthma, you don’t have to shy away from physical fitness. Take a couple of draws on your bronchodilator about 20 minutes before working out, and make sure you warm up for at least ten minutes.

Swimming is a good exercise, it improves one’s breathing. For anyone troubled by shortness of breath, but particularly for people with asthma, swimming is an ideal exercise.

Sometimes, sitting up in bed will help. If breathing is stressed when you lie down at night, put several books beneath the legs of your bed’s headboard, raising it between 30 and 45 degrees. This moves the abdominal organs into the abdominal cavity, and more space is available for the diaphragm to move downward.

Medications must be considered to treat the underlying conditions. For example, a patient’s asthma may be managed with corticosteroids to reduce lung inflammation. For asthma and many other respiratory conditions, doctors also prescribe bronchodilators—oral medications and inhaled sprays that help to open airways. Patients with severe asthma will benefit from receiving bronchodilators using a home nebuliser.

Collapsed lungs are diagnosed and treated in hospital settings. Depending upon the underlying condition the doctor may choose to put in the underwater seal drain of to put in a valve. An underwater seal drain is shown in the diagram below.

Picture 5. Underwater Seal Drain. A procedure which is performed in the hospital under aseptic conditions.

In an unconscious patient the nurse or physician will insert an oropharyngeal airway or an oropharyngeal tube into the mouth or nose respectively. This procedure prevents the tongue of the patient from falling and blocking the trachea, ordinarily known as the airway. Both types of airways are shown below.

Picture 6. Oropharyngeal airways for use with unconscious patient. Inserted into the mouth to prevent the tongue from falling back.

Picture 7. Nasopharyngeal airways for use with unconscious patient.

Last, but not lest the patient’s body must be aligned correctly to optimize breathing. Doctors and nurses are trained to do this all the time. If the person you are looking after becomes unconscious arrange for him/her to be transferred to a hospital for appropriate care.

Picture 8. Modern, High tech ventilator (breathing machine) used to breathe for patients who cannot breathe for various reasons. The condition must be reversible for a patient to be placed on a ventilator. If the condition is not reversible / treatable then placing the patient on a ventilator cannot be justified from a moral and ethical perspective.

The medical management of all the underlying causes and treatments is beyond the scope of this exercise and is not attempted. This article is for General and ICU nurses and for the public. It is not to be used for diagnostic or treatment purposes.