Respiratory depression: Causes, symptoms, and treatment

Respiratory depression means that a person's rate and depth of breathing are lower than normal. This results in low oxygen levels and high carbon dioxide levels in the blood. Without treatment, the condition can cause life-threatening complications, including coma and death.

Anything that depresses the central nervous system (the brain) can cause respiratory DEPRESSION since the brain controls a person's respiratory drive. In minor cases, symptoms may be unnoticeable.

Other symptoms in most cases include slow and shallow breathing. Oxygen therapy and respiration machines may be used in treatment, depending on the severity of each case.

Fast facts on respiratory depression:

·     Sedative medication, narcotic pain medications, and substances that depress brain function, such as alcohol and certain illegal drugs, are known to cause or increase the risk.

·     Symptoms include slow, shallow breathing, and in severe cases, respiratory failure or death.

·     Treatment options for respiratory depression depend largely on the severity of the case.

What is respiratory depression?

Respiratory depression is characterized by low, shallow breathing.

Respiratory depression refers to a failure of the lungs to exchange carbon dioxide and oxygen. This is a result of slow and shallow breathing.

Respiratory depression is also known as central hypoventilation. In most cases, breathing rates are reduced to 8-12 breaths per minute.

The condition can cause acid to build up in the body and lead to respiratory acidosis, a life-threatening condition associated with organ failure.

Common causes

Certain medications, in particular sedatives, and specific health complications are known to cause or increase the risk. Common causes of respiratory depression include:

Respiratory depression may be caused by poisoning or overdose from different substances, including opioids, sedatives, and barbiturates.

·         opiate or opioid (morphine, tramadol, heroin, fentanyl) overdose

·         postoperative (after surgery) opioid-induced or anaesthetic related respiratory depression

·         stroke that affects the lower brain stem

·         ethanol overdose or poisoning

·         barbiturate overdose or poisoning

·         sedative overdose or poisoning

·         benzodiazepine overdose or poisoning

·         congenital (present at birth) central hypoventilation syndrome (CCHS)

·         central sleep apnea

·         severely elevated blood ammonia as seen in liver failure and cirrhosis

·         brain tumour pressing on the brain stem at the respiratory centre

What are the symptoms?

The symptoms of respiratory depression depend on the severity of the case.

In more severe cases, the symptoms of respiratory depression become more evident.

Symptoms of respiratory depression

Associated symptoms include:

·         confusion

·         disorientation

·         lethargy

·         fatigue

·         headache

·         dizziness

·         nausea

Associated signs include:

·         shallow, slow breathing with little noticeable chest movement

·         vomiting

·         headache

·         high or low blood pressure

·         reduced or pinpoint pupils

·         decreased breathing sounds and a distinct whistling or crackling sound while breathing

·         tremors

·         apnea, or abnormally long pauses between breathing followed by a deep sigh sounding breath

·         bluish-coloured or tinted skin, especially in the toes and fingers

·         seizures

·         rapid heart rate

If left untreated, severe respiratory depression can result in the following:

·         respiratory arrest

·         cardiac arrest

·         brain damage

·         coma or death

·         reduced heart rate

If respiratory depression is suspected, or if several of the typical symptoms occur, seek medical attention immediately. If someone is in the company of someone with these symptoms, it is vital to keep the person alert and moving as much as possible.

Diagnosis

An electroencephalogram (EEG) may be performed in order to diagnose respiratory depression.

Doctors will usually begin by asking questions about symptoms and reviewing a person's individual medical history and medication profile. They will then perform a physical exam to look for signs of abnormal breathing and heart rhythms.

After an initial visit, a doctor will usually order diagnostic tests to help confirm respiratory depression and evaluate its extent.

Tests used to diagnosis the condition include:

·         urine and serum drug screens

·         alcohol level

·         screen for other toxins

·         serum ammonia level

·         blood gas test, to calculate the ratio of acid/base and the amount of carbon dioxide and oxygen in the blood

·         computed tomography scan (CT) or magnetic resonance imaging (MRI) of the brain to check for stroke or a tumour

·         electroencephalogram (EEG)

Treatment

Common therapies and medications used to treat the condition include:

·         oxygen therapy

·         if caused by overdose, detoxification, often using medications that work against the effects of opioids, such as naloxone, methadone, and Suboxone

·         fluid therapy, either intravenously or orally administered

·         continuous positive airway pressure, CPAP, or BiPAP, machines

·         mechanical ventilation

Prevention

Some cases of respiratory depression are unpreventable, caused by accident or sudden disease. Some cases, however, can be prevented.

Ways to reduce the chances of developing the condition include:

·         avoiding, or taking extra precautions when using sedative medications

·         monitoring children while taking prescribed medications

·         avoiding excessive alcohol use

·         avoiding or taking extra precautions when using narcotic medications