Respiratory depression (A brief guide)

In this guide, we will discuss what respiratory depression is, signs, symptoms, possible causes and treatment.

What is Respiratory depression?

Respiratory depression or central hypoventilation is a breathing disorder that is characterized by slow and ineffective breathing.

During a normal breathing cycle, you are meant to receive the appropriate amount of oxygen into -your lungs, if you have respiratory depression the oxygen received gets reduced (between 8-12  breaths per minute).

Breathing fast doesn’t necessarily mean you are hypoventilating.

Nonetheless, some people may start breathing faster than usual as an attempt from their bodies to knock out the excess of carbon dioxide.

Additionally, it can cause acid to build up in your body and lead to respiratory acidosis, which is considered a life-threatening condition where organs may start to fail. 

Respiratory system

Our respiratory system is composed of your nose, sinuses, mouth, throat, voice box, windpipe, and lungs.

When we have an upper respiratory infection, it means that the infection is affecting the parts of the respiratory tract that are higher on the body (nose, sinuses, and throat). 

If your doctor says you have a lower respiratory infection it means the infection is affecting your airways and lungs. 

Did you know?

….after about four minutes without oxygen, brain cells begin dying. Which can lead to brain damage and ultimately death? 

….lung cancer is often associated with smoking, but the disease can affect non-smokers as well?

….there are physicians who specializes in the respiratory system called pulmonologists?

….the average resting respiratory rate for adults is 12 to 16 breaths per minute, and up to 40 to 60 breaths per minute during exercise?

How do we breathe?

We all know we need oxygen to live, but since we do it without even thinking, we forget how important it is and sometimes we are not even aware of the process itself.

We breathe in oxygen (O2) and breathe out carbon dioxide (CO2), where this exchange of these 2 gases is mediated by our lungs.

Inhaling oxygen results in it being transferred to our cells in the rest of our body for us to stay alive.

However, many people are unaware that the CO2 we exhale, actually plays a very important role in how our bodies work by maintaining the balance of pH (acid-base) of our blood. 

Our muscles engage when we inhale, working to pull the air in.

Someone that suffers from respiratory depression, isn’t allowing the needed amount of air into the lungs to allow for normal gas exchange to take place, resulting in low levels of O2 and higher concentrations of CO2 in their bodies. 

In contrast, when our muscles relax, exhalation occurs passively.

If there is a problem when breathing deeply, we will not exhale enough which in the end will result in a higher concentration of acid in our blood, causing any number of body systems to fail due to massive cell death. 

Causes of respiratory depression

There are several reasons why you can have respiratory depression.

Some of the most common causes include:

  • Neuromuscular diseases that weakens the muscles involved in breathing.
  • Deformities in the walls of your chest, such as pectus excavatum (concave chest)
  • Morbid obesity
  • Brain injury: strokes can affect the lower brain stem, which is essential for breathing control.
  • Obstructive sleep apnea
  • Chronic lung disease
  • Postoperative (after surgery) opioid-induced or respiratory depression caused by anesthetic agents.
  • Severely elevated blood ammonia as seen in liver failure and cirrhosis.
  • A brain tumor pressing on the brain stem
  • Congenital central hypoventilation syndrome (CHHS): this is a disorder of the autonomic system that affects breathing. This can result in hyperventilation especially when sleeping. 
  • Hypocapnia: this is a condition that results in low CO2 concentration in the blood. 
  • Chronic mountain sickness: this is an illness acquired from living at high altitudes.

Additionally, it has been suggested that hypoventilation can also be a side effect of certain medications or substances, such as it is the case of large doses of central nervous system depressant drugs. 

Medications and substances that can potentially cause hyperventilation are:

  • Alcohol: ethanol overdose/poisoning.
  • Barbiturates: overdosing/poisoning on barbiturates 
  • Sedatives: overdosing/poisoning on sedatives
  • Opioids overdose
  • Benzodiazepines overdose or poisoning
  • Certain illegal drugs

How is respiratory depression diagnosed?

Your doctor will perform a serious of tests and exams to determine if you have respiratory depression.

Additionally, it may ask you to describe your symptoms and if you are taking any medication.

After, it may perform a physical examination and additional tests to make a diagnosis. 

What kind of tests do they use?

According to Medical News Today, some of the tests used to diagnose this condition include:

  • urine and serum drug screens
  • alcohol level
  • screen for other toxins
  • serum ammonia level
  • computed tomography scan (CT) or magnetic resonance imaging (MRI) of the brain to check for stroke or tumor
  • electroencephalogram (EEG)

Some other exams and tests that your doctor may ask for according to Valencia Higuera from HealthLine are:

  • X-ray of your chest: this is one of the most commonly performed X-rays. This helps to view your heart, lungs, airways, blood vessels and bones of the spine and chest.
  • Pulmonary function test: these include a series of tests to check how the lungs are working. One of the tests is called spirometry, which measures the amount of air your lungs can hold.
  • Blood gas test (arterial blood gas): This test measures the amount of oxygen and carbon dioxide in your blood. It can also help to determine the PH of your blood or acid. 
  • Pulse oximetry test: measures the oxygen level of your blood or oxygen saturation. 
  • Hematocrit and hemoglobin blood test: it is usually used to check for anemia along with a hemoglobin test or as part of a complete blood count.
  • Sleep study: this exam helps your doctor monitor your sleeping patterns and detect any sleeping disorders.

Symptoms of respiratory depression

Symptoms tend to vary and they can go from mild to moderate. Some of the symptoms may include:

  • Feeling tired
  • Confusion 
  • Disorientation
  • Feeling sleepy during the day
  • Shortness of breath
  • Superficial breathing
  • Depression
  • Nausea
  • Headaches 

Some additional symptoms may manifest as the levels of carbon dioxide increase (Medical News Today):

  • Bluish-colored lips, fingers or toes (Cyanosis)
  • Having seizures
  • 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
  • seizures
  • rapid heart rate

How is respiratory depression treated?

Don’t panic, this is a treatable condition but the appropriate treatment depends on the cause for respiratory depression.

For example, if you have respiratory depression as a side effect of your medication then your doctor may stop the medication and check if your normal breathing is restored.

Other possible treatments may include:

  • Oxygen therapy to support breathing
  • Weight loss if you have obesity.
  • CPAP and/or BiPAP, which is meant to be used to send air through a tube into a mask that fits over your nose. 
  • May require surgery to correct any chest deformities.
  • Medication to open your airways and treat your lung disease such as inhaled corticosteroids (e.g. Fluticasone, Budesonide, Mometasone, Beclomethasone, Ciclesonide) 
  • If you have overdosed, then the detoxification will be needed often using medications that work against the effect of opioids, such as naloxone, methadone or suboxone. 

Respiratory depression complications

If respiratory depression is left untreated, it can cause life-threatening complications, even death. 

If you develop respiratory depression from a drug overdose it can lead to a respiratory arrest, where you can stop breathing or breath with difficulty, often simultaneously occurring with cardiac arrest. 

If your respiratory depression progresses it can also lead to pulmonary hypertension, which is high blood pressure in the arteries of your lungs making it harder for your heart to pump the blood through and it can eventually result in right-sided heart failure or a reduced heart rate.

Additionally, since there is not enough oxygen being carried through your blood to the brain, then the risk of developing brain damage increases tremendously. 


If you suspect you or someone else is having respiratory depression, or if several of the symptoms manifests, seek immediate medical attention.

According to  Medical News Today, if you are with someone with respiratory depression it is important to keep the person alert and moving as much as possible.

Why is this blog about respiratory depression important?

Breathing air is done as an automatic process, we don’t have to think or do anything for us to breathe.

However, it is important to know what happens if the amount of air we inhale is not enough or if it gets obstructed or reduced.

Many health problems can manifest and can carry major consequences.

This is why being aware of this condition, the symptoms, signs, and treatment options is highly regarded.

If left untreated or unattended it can rapidly have major life-threatening consequences and even, in the worst-case results in death. 

Frequently Asked Questions (FAQs) about respiratory depression

What are the signs of respiratory distress?

The common symptoms and signs for Acute Respiratory Distress Syndrome may include labored and rapid breathing, muscle fatigue, and general weakness, low blood pressure, discolored skin or nails, a dry cough, a fever, headaches, and a fast pulse rate.

What class of drugs causes respiratory depression?

Some of the drugs that can cause respiratory depression include opiate or opioid overdose, postoperative opioid-induced or anesthetic related respiratory depression, sedatives, barbiturates, and certain illegal drugs. 

What are the signs and symptoms of hypoventilation?

The signs and symptoms of hypoventilation are: daytime drowsiness, fatigue, morning headaches, swelling of the ankles, waking up from sleep unrested, waking up many times at night and bluish coloration of the skin, lips, and toes caused by lack of oxygen.

How do you get respiratory distress?

The acute respiratory distress syndrome or ARDS occurs when the alveoli (elastic air sacs in our lungs) get filled with fluid liquids.

This fluid keeps our lungs from getting enough air, resulting in less oxygen in our bloodstream. 

What is Cheyne Stoke breathing?

The Cheyne-Stokes respiration is considered an abnormal breathing pattern characterized by progressive deeper and sometimes faster breathing followed by a gradual decrease that subsequently results in apnea.

This pattern then repeats, with each cycle taking between 30 seconds to 2 minutes approximately. 

  1. Chronic Obstructive Pulmonary Disease: Co-Morbidities and Systemic Consequences (Respiratory Medicine) 
  2. Depression and Anxiety in Patients with Chronic Respiratory Diseases



Medical News Today

Medicine Net

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