The following describes what exactly respiratory depression or hypoventilation is, what can cause it, and what symptoms may indicate that it is occurring. Furthermore, information is given on the medical diagnosis, the course, and the treatment and prevention of respiratory depression.
What is respiratory depression?
The normal number of breaths in an average adult is about 16 to 20 breaths per minute. Respiratory depression is said to occur when the frequency of breaths is decreased, that is, when breathing slows down with fewer than ten breaths taken every minute. However, these do not necessarily contain less volume than is the case when breathing at a normal rate, which is why respiratory depression does not normally lead to respiratory distress in the affected person. What is problematic, however, is that this does not allow the body’s gas exchange to proceed optimally, which can lead to difficulties in maintaining the person’s organ functions.
Causes
Respiratory depression occurs when the respiratory center does not respond optimally to the respiratory drive that regulates the carbon dioxide (CO2) as well as the oxygen (O2) content of the blood. For example, if the CO2 content of a person’s blood is too high, increased respiratory drive can increase the number of breaths per minute to cause a reduction of CO2 in the blood through its expiration. If a person suffers from respiratory depression, this gas exchange can no longer take place properly because breathing is too superficial or too slow. This leads to an increased partial pressure of CO2 in the blood and there is a risk of suffocation of the affected person. A distinction must be made between peripheral and central respiratory depression. In peripheral respiratory depression, the cause is not the central control in the central nervous system, which is still preserved in this case, but in the periphery. It may be caused by an overdose of muscle relaxants, various neurological diseases, or airway obstruction. In central respiratory depression, on the other hand, the respiratory center in the brain is no longer fully functional. This occurs, for example, due to certain medications, craniocerebral trauma, sleep apnea syndrome, increased intracranial pressure, poisoning of the body with alcohol or morphine, for example, or due to a cerebral infarction.
Symptoms, complaints, and signs
Respiratory depression is primarily manifested by slowed breathing. As it progresses, this leads to shortness of breath and shortness of breath. Eventually, acute choking symptoms occur and result in a panic attack, which is manifested by sweating and an elevated pulse. Respiratory depression is also manifested by sleep problems, fatigue and anxiety. Mental deficits may also occur, as well as confusion and poor concentration. Many sufferers experience muscle twitching or cyanosis, a blue discoloration of the skin that is particularly noticeable on the fingers and the mucous membranes in the mouth. Furthermore, respiratory depression can cause psychological problems. For example, depression and anxiety disorders are sometimes associated with chronic hypoxia of the brain. As the disease progresses, the aforementioned symptoms increase in intensity and usually lead to further complaints. Externally, respiratory depression can be recognized primarily by the aforementioned cyanosis and characteristic muscle twitching. However, pallor and changes in pupil size may also occur. Finally, respiratory depression is manifested by respiratory arrest, which leads to death if left untreated. Respiratory depression resulting from morphine poisoning may be manifested, for example, by nausea and vomiting, lassitude, and a number of other symptoms.
Diagnosis and course
Possible symptoms that may be caused by respiratory depression include shortness of breath, sleep problems, weakness, anxiety, confusion, delirium, fatigue, seizures, muscle twitching, or cyanosis of the ill person. However, these possible symptoms by no means allow a definite diagnosis of respiratory depression, which can only be diagnosed by a blood gas analysis performed by a physician. This can also determine the exact degree of respiratory depression, the extent to which it is hazardous to the patient’s health, and what measures need to be taken.The course differs depending on the degree of respiratory depression. In the case of marked respiratory depression, respiratory arrest may eventually occur after a steady increase in blood CO2 levels and severe respiratory problems if adequate measures are not taken to counteract these reactions.
Complications
Respiratory depression can cause a number of complications. Initially, fatigue, muscle twitching, or confusion occur as a result of the reduced respiratory rate; symptoms that can lead to seizures, delirium, and anxiety disorders as the condition progresses. If left untreated, respiratory depression also leads to respiratory distress, which becomes more severe as it progresses and can eventually lead to respiratory arrest. If no acute treatment is given by then at the latest, circulatory collapse will occur and subsequently coma and death of the affected person. Respiratory depression as a result of morphine poisoning is accompanied by other symptoms such as nausea and vomiting as well as fatigue. Complications can arise in the treatment of respiratory depression if artificial respiration becomes necessary; there is then a risk of sore throat, cough, chronic infectious diseases or pneumonia. Rarely, hemoptysis, bloody sputum resulting from a severe infection, may also occur. Certain medications can also exacerbate respiratory depression and subsequently cause sleep apnea, increased intracranial pressure, or even cerebral infarction. Early treatment of the condition is the most effective means of preventing a severe course and any complications of respiratory depression.
When should you see a doctor?
Ideally, respiratory depression is prevented by regular screening and comprehensive medical treatment. Patients at risk (those with nerve injury, trauma, or neurologic disease) should clarify possible consequences and risks of the underlying condition. The same applies to people who regularly take opioids, barbiturates or sedatives. By clarifying the risks, a rapid and comprehensive response can be made in the event of respiratory depression. If acute respiratory depression occurs, the emergency physician must be alerted immediately. Whether hyperventilation is present can be determined by various warning signs. Most often, the symptom is associated with decreased breathing movement, blue lips or fingers, and fatigue. As it progresses, circulatory weakness and eventually respiratory failure occur. If one or more of these signs can be observed, the affected person must receive immediate medical treatment. First aid measures and, under certain circumstances, resuscitation measures must be carried out until the rescue service arrives. In addition, if possible, the cause of respiratory depression should be determined to allow rapid treatment.
Treatment and therapy
Treatment of respiratory depression primarily addresses its trigger, as this is the only way to fully counteract respiratory depression. Thus, if a patient is diagnosed with respiratory depression due to intoxication with morphine, in addition to treating the morphine intoxication with the morphine antagonist naloxone and gastric lavage, the symptoms of respiratory depression are also counteracted, for example, by intubation and mechanical ventilation or cardiac massage of the affected person. The type of treatment continues to depend on the degree of respiratory depression. If the sufferer suffers from severe respiratory problems and the heart and brain are no longer supplied with sufficient oxygen, he or she may have to be ventilated before the actual causes leading to these complaints can be addressed.
Outlook and prognosis
Respiratory depression can lead to a life-threatening condition without medical treatment. The permanent undersupply of oxygen to the organism triggers shortness of breath, sleep disturbances, and permanent high blood pressure. Without medical treatment, the risk of sudden dysfunction or system failure increases. An acute condition is imminent, which can lead to lifelong impairments or secondary diseases. In severe cases, multiple organ failure sets in, resulting in a fatal outcome. The risk of heart failure increases with the permanent overload of the heart muscle in hypertension. The patient is threatened with considerable health problems for the rest of his or her life or even a fatal course of the disease.With medical care for the patient, the chances of recovery increase immensely. In the case of mild respiratory depression, there is a good chance of freedom from symptoms. Learning breathing techniques or how to manage healthy breathing in various situations can provide lasting relief. The more pronounced the condition, the greater the likelihood that ongoing medical care will be needed to prevent deterioration. If respiratory depression is pronounced, the chances of recovery decrease significantly. If there is no possibility of the CO² level in the blood rising permanently, significant irregularities occur. These can lead to an unexpected respiratory arrest and thus to the death of the patient.
Prevention
To prevent respiratory depression, the same applies: since respiratory depression is not a disease in its own right, but is triggered by other malfunctions of the body, the only possible preventive measure is to avoid it if possible.
Aftercare
Mild respiratory depression offers a good chance of complete recovery. If this is successful, there is no need for follow-up care. Recurrence is not expected for the time being. However, this does not mean that immunity will develop, for example. The patient may again suffer from the same or other causes that trigger respiratory depression. The situation is different if the causes of respiratory depression are not cured causally. Then the typical complaints arise. Respiratory depression leading to death can occur at any time. It is important to prevent complications and to realize a symptom-free everyday life. The attending physician usually orders imaging procedures as part of follow-up care. CT and MRI in particular provide clarity about muscle and nerve damage. Depending on the intensity of the underlying disease, the physician determines outpatient or inpatient monitoring. In many cases, drug therapy is sufficient. Naloxone, for example, acts as an antidote when respiratory depression is triggered by opioids. In other cases, breathing training helps. The patient learns how to ensure a sufficient number of deep breaths. In acute life-threatening situations, artificial respiration is unavoidable. This prevents oxygen deficiency in the brain. Individuals who witness decreased breathing must be sure to call 911.
This is what you can do yourself
Respiratory depression is typically recognized by a decreased breathing rate of less than ten breaths per minute. There is then a general decrease in the supply of oxygen to the body. This can cause symptoms such as confusion, seizures, muscle twitching, and the externally visible blue discoloration of the skin (cyanosis). Respiratory depression can have many different causes, so adjustments in daily life and any self-help measures must be guided by these. If a person experiences acute respiratory depression, quick action is required, so alerting an emergency physician is recommended because life-threatening respiratory arrest can also occur. In cases where respiratory impairment occurs due to prolonged drug abuse or intoxication, an initial self-help measure may be voluntary induced vomiting, for example. The most common cause of breathing cessation is nocturnal sleep apnea attacks caused by obstruction of the trachea by the uvula at the soft palate. The most important self-help then is to prevent tracheal obstruction by taking appropriate measures such as wearing a CPAC mask that works with slight positive pressure. Respiratory depression may be either centrally controlled by the respiratory center or due to local organic problems. Adaptation to daily life and self-help is often not possible in such cases. Artificial respiration – temporary or permanent – may even be necessary as an emergency measure.
