Respiratory Depression

Overview

Respiratory depression, also called hypoventilation, means breathing that is too slow or too shallow to move enough air in and out of the lungs. When breathing slows down this way, the body cannot take in enough oxygen or get rid of enough carbon dioxide. As a result, oxygen levels in the blood fall and carbon dioxide builds up, which can quickly become dangerous.

Respiratory depression is most often caused by medications or substances that slow down the part of the brain that controls breathing, especially opioids, sedatives, and alcohol. It can range from mild slowing of the breath to a complete stop in breathing, which is life-threatening. Recognizing the warning signs early and getting emergency help can be life-saving.

Symptoms

Signs of respiratory depression reflect both the slowed breathing and the falling oxygen levels:

• Slow breathing rate
• Shallow or weak breaths
• Drowsiness, confusion, or difficulty staying awake
• Slurred speech
• Bluish lips, fingertips, or skin (a sign of low oxygen)
• Pinpoint pupils when opioids are involved
• Snoring or gurgling sounds in someone who is very sedated
• Unresponsiveness in severe cases

Severe respiratory depression can lead to a complete stop in breathing, loss of consciousness, and cardiac arrest. This is a medical emergency. Call emergency services immediately and, if an opioid is suspected, give naloxone if it is available.

Causes

Respiratory depression usually results from something that slows the brain's drive to breathe or weakens the muscles used for breathing. Common causes include:

• Opioids: Prescription painkillers and illicit opioids are a leading cause, especially in overdose or when combined with other sedatives.
• Sedatives and sleep medicines: Such as benzodiazepines, particularly when mixed with opioids or alcohol.
• Alcohol: Heavy drinking, especially together with other depressants.
• Anesthesia: Medications used during surgery, monitored closely by the care team.
• Medical conditions: Severe lung disease, certain neurological or muscle disorders, and conditions that affect the brainstem.

Combining multiple substances that depress breathing greatly increases the risk.

Risk Factors

• Use of opioids, especially at high doses or after a period of not using them
• Combining opioids with sedatives, sleep aids, or alcohol
• Older age
• Severe lung disease such as advanced COPD
• Sleep apnea or other breathing disorders
• Certain neurological or muscle conditions
• Kidney or liver problems that affect how medications are cleared

Diagnosis

In an emergency, respiratory depression is recognized by observing slowed, shallow breathing and decreased responsiveness; treatment begins immediately. In a medical setting, evaluation may include:

• Monitoring breathing and oxygen: Counting the breathing rate and measuring oxygen levels with a pulse oximeter.
• Blood tests: Arterial blood gas tests to measure oxygen and carbon dioxide levels directly.
• History and examination: Identifying medications, substances, or conditions that could be responsible.
• Additional tests: Such as imaging or other tests to find an underlying cause when needed.

Treatment

Treatment focuses on supporting breathing and reversing the cause:

• Emergency breathing support: Providing oxygen and, if needed, assisting or taking over breathing with a bag-mask or breathing machine.
• Naloxone for opioids: If opioids are the cause, naloxone can rapidly reverse the effect on breathing and may be given by bystanders or first responders. Repeat doses and ongoing monitoring may be needed.
• Reversing other sedatives: Specific reversal agents may be used in certain cases under medical care.
• Treating the underlying cause: Managing lung disease, infection, or other conditions contributing to the problem.

Anyone who has had significant respiratory depression needs close monitoring, since the effect of long-acting drugs can return after a reversal agent wears off.

Prevention

• Take opioids and sedatives only as prescribed and never mix them with alcohol or other sedatives without medical advice
• Store medications safely and out of reach of children and others
• Ask about naloxone if you or a household member uses opioids, and learn how to use it
• Tell your doctor about all medications, including sleep aids, to avoid dangerous combinations
• Use caution with sedating medications if you have lung disease or sleep apnea

When to See a Doctor

Respiratory depression is a medical emergency. Call emergency services immediately if someone has:

• Very slow, shallow, or stopped breathing
• Bluish lips, face, or fingertips
• Extreme drowsiness or cannot be woken
• Gurgling, snoring-like sounds while deeply sedated
• Unresponsiveness

If an opioid overdose is suspected and naloxone is available, give it while waiting for help, and stay with the person. Even after naloxone, the person needs emergency evaluation because breathing problems can return.

Related Topics

Frequently Asked Questions

References

1. Centers for Disease Control and Prevention (CDC). Opioid overdose.
2. MedlinePlus, U.S. National Library of Medicine. Breathing problems.
3. National Institute on Drug Abuse (NIDA). Naloxone.
4. Mayo Clinic. Hypoventilation.