What is Respiratory Depression?

What is respiratory depression

What is respiratory depression? Respiratory depression occurs when the body cannot adequately exchange oxygen and carbon dioxide. This can happen for several reasons, but one of the most common is an overdose on drugs that depress breathing. In this blog post, we will discuss respiratory depression definition, including symptoms, causes, treatment options, and prevention methods.

Definition of Respiratory Depression

Respiratory depression or hypoventilation is a state of respiratory insufficiency that can be caused by many different factors. Respiratory depression might also refer to the lack of ability to maintain normal breathing patterns in the central nervous system. This occurs when there isn’t enough oxygen in the air we breathe, and carbon dioxide in exhaled breath accumulates.

Symptoms of this breathing disorder include shallow breathing, which may be as slow as eight to ten breaths per second whereas, an average person breathes 12 to 20 times per second.

Respiratory depression can be caused by many different factors, including overdose on drugs like alcohol or benzodiazepines. It can also be caused by conditions that affect the brain and central nervous system.

Levels of Respiratory Depression

According to Mosby’s Medical Dictionary, when an individual’s breathing rate falls below 12 breaths per minute or their lungs are not being fully ventilated, they are experiencing respiratory insufficiency. Though there might be many reasons for hypoventilation, like sudden disease or accidents, substance-induced respiratory depression/suppression is the most common type.

Doctor checking patient's lung for breathing problems

Substance-induced respiratory depression can be divided into four broad levels;

  1. Minimal Respiratory Depression: This level is usually undetectable and can be accompanied by mild levels of sedation. The individual using these substances medicinally might experience this effect if they have a high tolerance for the substance or take it in low doses.
  2. Moderate Respiratory Depression: The situation when the individual notices their slow breathing but doesn’t feel uncomfortable. Mild hypoventilation can occur when one uses higher doses of central nervous system depressant substances. In this level of depression, the patient might take only 1 or 2 breathes less than the 12 breaths per minute standard.
  3. Severe Respiratory Depression: Severe hypoventilation happens when the doses of central nervous system depressants are so high that they can be dangerous for the patient’s health. Breathing rate per minute becomes significantly lower, and in most cases, it becomes the centre of the patient’s attention. Some symptoms of this level may include falling short of breath, experiencing confusion or anxiety, gasping of air etc. If not appropriately treated with professional medical advice, it can lead to life-threatening complications.
  4. Respiratory Failure: This is when someone becomes unconscious or breathes completely stops (such as respiratory arrest). At this level, the amount of oxygen supply becomes dangerously low. Anoxia can develop in those experiencing hypoventilation—a total lack of oxygen to the organs, resulting in severe injury or even death if left untreated. Losing oxygen level is not just a threat because it can lead to things like injury and death. It also puts people at risk for other dangers such as heart attack, stroke, and a seizure disorder that come with respiratory system failure.

Symptoms of Respiratory Depression

Individuals with respiratory depression may experience the following symptoms:

Abnormal breathing sounds

There are specific sounds that indicate abnormal breathing that doctors listen for when observing a person’s breath—the sounds an individual makes when breathing may indicate respiratory depression. Doctors can hear a whistling sound, crackling sounds, diminished exhalations, or even gasping.

Increased heart rate

Individuals with respiratory depression may experience increased heart rates. This is the body’s automatic response to attempting to boost oxygen intake.

Doctor checking heart rate of a female senior patient

Agitation and restlessness

If severe respiratory depression is present, individuals may become agitated and restless.

When early symptoms are not addressed, the following signs can worsen the condition:

  • Confusion
  • Disorientation
  • Bluish skin, lips, and fingers
  • Visual difficulty and headaches
  • Fatigue and sleepiness during the day
  • Sleeping too much and having trouble staying awake at night
  • Seizures
  • Breathes pauses that are abnormally long
  • Nausea
  • A feeling of mental drowsiness

How to Diagnose Respiratory Depression

If you have respiratory depression, seek medical treatment.

In addition to asking about your symptoms, your doctor may ask about some of your personal data, like previous medical conditions and medications. After they have examined you and performed tests, they will provide medical advice.

For purposes of determining the cause of respiratory depression, your doctor may order several tests. A few of the tests include:

  • Chest X-ray: images of your chest are taken to check for abnormalities.
  • Lung function test: determines whether your lungs function well.
  • Blood gas test: measures oxygen and carbon dioxide levels in your blood and your body’s acid-base balance
  • Pulse oximetry test: measures blood oxygen levels by using a finger-tip monitoring device.
  • The haemoglobin and hematocrit blood tests: measure how many red blood cells can transport oxygen to your body during sleep;
  • Sleep studies: diagnoses sleep-related disorders, like sleep apnea.

Causes of Respiratory Depression

The following are some health conditions that can lead to respiratory depression.

Medical device kit for sleep apnea diagnosis

Neuromuscular diseases

Even when the neurological breathing impulse remains intact, individuals with neuromuscular disease may experience rapid, shallow breathing due to respiratory muscle weakness and lack of muscle control. Usually, the complications become severe during sleep.

Brain Injury

A brain injury may make it difficult for the brain to control basic functions, such as breathing. As a result of a brain injury, hypoventilation can be caused by impaired consciousness and reflexes.

Chest wall deformities

As a result of the physical limitations caused by chest wall deformities, kyphoscoliosis and fibrothorax can impair the breathing rate and lung function.


In some people, severe obesity can result in a condition called obesity-hypoventilation syndrome (OHS).

Sleep Apnea

Hypoventilation occurs when an individual with obstructive sleep apnea (OSA) has their airways blocked or collapses during the night, causing them to struggle to breathe.

Medication and Drug Overdose

As well, taking large doses of some medications and substances may increase your chances of experiencing respiratory depression. The side effect of some drugs can lead to hypoventilation.

You can experience hypoventilation from the following medications:

  • alcohol
  • sedatives
  • opioids
  • barbiturates
  • benzodiazepines

If medication triggers hypoventilation, it’s best to stop taking the medication to restore normal breathing rate and brain function. Be sure to consult with doctors with the necessary medical expertise as well.

Woman with illness taking medicine

How to Treat Respiratory Depression

Patients with respiratory suppression at lower levels (levels 1 and 2) may need to modify their medication dosage if the side effects they are experiencing cause them distress. To control the impact of central nervous system depressants, illicit users must reduce their intake.

In the case of respiratory arrest caused by opiate abuse, drugs such as naloxone, an opioid antagonist, can be administered for more severe respiratory suppression.

Medical treatment is mandatory when drug-induced respiratory depression occurs in other ways. Among the most common treatments and therapies for respiratory depression are:

  • Oxygen therapy: a process of delivering oxygen for the patient to breathe. Oxygen therapy can be administered by tubes resting in his nose, a mask placed over his face, or a tube inserted directly into his trachea. He receives and delivers more oxygen to his blood as a result of this treatment.
  • Sleeping with a bi-level positive airway pressure (BiPAP) or continuous positive airway pressure (CPAP) machine.
  • Correcting chest deformity through surgery.
  • Surgery and medication for weight loss.
  • Treatment of persistent lung disease with inhaled medications.
  • Mechanical ventilation.
  • Intravenously or orally administered fluid therapy.
  • In cases of hypoventilation caused by certain medications, stopping the medication usually restores normal breathing.
  • The detoxification process is necessary if sedative drug overdose causes respiratory depression. To reverse the effects of an overdose, doctors will use medications.

Patient is assisted by a breathing oxygen apparatus

How to Prevent Respiratory Depression?

We cannot always prevent hypoventilation caused by an accident or a sudden illness. There are, however, ways to reduce respiratory depression in some cases.

  • If you continue to consume alcohol, the depressant will accumulate in your system and lead to a situation where it can slow or stop breathing.
  • Pace your drinking and alternate with water to avoid the accumulation of a depressant.
  • If you are taking any medications, consult with an expert before consuming alcohol as it may lead to respiratory depression or other side effects related to medication use.

Wrapping Up

Thanks for reading this blog post on respiratory depression. If you have any questions or thoughts about the topic, please leave a comment below. We’d love to hear from you! Feeling like something is wrong with your breathing? Be sure to seek medical advice right away.

As always, feel free to share your experience with us in the comments section below to learn more about how others are coping with their condition as well.