Patient-Controlled Anesthesia (PCA)

Patient-controlled analgesia (PCA) is a type of pain management system that allows patients to make their own decisions as to when they need to take a dose of pain medication. The medication is administered through a PCA pump and can be used to treat acute (sudden, severe), chronic (long-term), or postoperative (after surgery) pain. It can also be utilized in obstetrics for the management of labor pain.

When it comes to pain management, it is helpful to understand your options so you and your healthcare provider can make the best decision for your care.

patient controlled anesthesia (PCA)

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What Is a PCA Pump?

PCA is a method of pain management that lets the patient decide when they need a dose of pain medicine. The pump is accessible 24/7 and the patient simply presses a button to administer a pre-set dosage of medication to alleviate pain. This system allows the patient to receive smaller doses of medication, more often (compared to traditional pain medication administration). There is a max dose programmed on the PCA pump as well to ensure there's no risk of overdose or toxicity.

What Is PCA Used For?

There are many scenarios in which a PCA pump is commonly used, including:

  • Pain management after surgery
  • Medical conditions that are painful such as cancer and other chronic (long-term) conditions
  • A way to give pain medication to those who cannot take medication by mouth
  • A method of pain control for hospice patients with moderate to severe pain—such as pain caused by cancer—to be utilized in a home care environment
  • Children—as young as 7 years of age—provided they can follow the instructions
  • A method of pain control for women during labor

Who Should Not Use a PCA System?

A contraindication is a specific situation in which a drug or procedure should not be used because it could cause harm. There are some scenarios in which a PCA pump is contraindicated, these include:

  • Elderly people who are confused
  • Very young children who cannot follow the instructions for proper use of the pump
  • Those who are unresponsive or disoriented
  • Those with a systemic infection (an infection that involves the entire body)
  • A person who has an infection at the site of the PCA placement
  • A person with allergies to the selected medication
  • A person who has had burns or trauma in the area of the PCA placement

Some situations are not strictly contraindicated, but they require closer observation and the discretion of the healthcare provider as to whether they should use a PCA, these people include:

  • Those with sleep apnea
  • People with kidney failure

How Does a PCA System/Pump Work?

The PCA pump was designed to deliver the patient’s specific dose of pain medication on a schedule that is customized to the patient’s needs. This process involves a predetermined bolus dose of medication that is released on-demand at the press of a button. Note, a bolus is a single dose of a drug, given over a short period of time, usually by infusion or injection.

The bolus can be given alone or combined with a continuous low dose of pain medication, depending on the healthcare provider’s order.

The pain medication, that is controlled by the pump, can be delivered via several modes of administration, including:

  • Intravenously: Through a needle placed in a vein, usually in the arm, but also in the epidural space
  • Via an epidural: A type of anesthetic used for pain control
  • Transdermally: Absorbed through the skin

The type of drugs commonly given via the PCA pump include:

  • Opioids (such as morphine)
  • Local anesthetics
  • Dissociatives (a type of drug that changes a person’s perception of pain)
  • Other analgesics

A PCA pump has a needle that is attached to an intravenous (IV) line. The needle is placed into a vein and a pump computer that’s configured to the IV. The computer is calibrated and set to deliver the exact amount of medication that your healthcare provider has ordered for you. The pre-calibrated pump allows the pain medication to be released when you press the handheld button.

Setting up the Patient-Controlled Anesthesia System

The steps involved in administering the PCA system include:

  1. The medical professional orders the right medication and dosage for you (common types of medication used for pain in PCA pumps include hydrocodone and morphine).
  2. The prescribing healthcare provider will calculate exactly how much medication you will receive each time you press the button, the time interval between doses, and the total amount you can receive over a specific time period. This is done to ensure you do not get too much medicine.
  3. A low dose of pain medication may be calibrated to be injected continuously to establish a base level of pain control.
  4. Each of the calculations made by the prescribing healthcare provider will be programmed into the pump.
  5. The nurse sets up the pump to enable it to release the correct amount of medicine from the syringe.
  6. The nurse will teach you how to use the PCA pump.
  7. When pain is first detectable, you press a handheld button, and pain medication is released from the system, through your IV, and into your vein.
  8. The medication travels from the pump into the tubing that goes into the needle and then to your vein.
  9. The pump will keep a record of each time you press the button and how much pain medication you receive.
  10. The IV will continually have fluid running through it to keep your vein open and to maintain adequate hydration.
  11. You may have bedside monitoring of oxygen levels and your vital signs (blood pressure, pulse, and respiration).
  12. Once your pain is not as severe, you may be switched to oral (by mouth) pain medications and the PCA pump will be discontinued.

Studies have shown that pain medication administered by the PCA pump is more effective than opioid injections, which are usually given by the nurse or someone who is trained to give injections. The PCA system is also shown to have a higher rate of patient satisfaction.

Safety Monitoring

There are several safety measures necessary when a person has a PCA pump, such as:

  • Frequent monitoring by a nurse to ensure your breathing (and other vital signs) is normal
  • A pulse oximeter is placed on the finger; the device measures a person’s oxygen level and has an alarm that goes off if the O2 level falls below a normal range. It's important to note that decreased respiration is one of the most dangerous side effects that could occur when a person uses a PCA pump; if a person’s breathing is depressed, it causes the oxygen level to decrease. 
  • Family members and other visitors are instructed to immediately report any breathing problems experienced by a patient using a PCA pump

Pros and Cons of a PCA System

Benefits of a PCA

There are many benefits of a PCA pump for pain, these include:

  • More effective pain control: From not having to wait until the pain is severe to get medication from the nurse.
  • Less anxiety and depression: Many people feel a sense of comfort that they are able to manage their own pain management.
  • Less medication: This can lower side effects such as drowsiness.
  • Autonomy: Patients often feel they can be more autonomous and have a better sense of control over their own pain management.

Risks of a PCA System

Although PCA is relatively safe and effective, as with any type of pain management regime, there are risks associated with PCA. These include side effects from opioid medication (a controlled drug that can be addictive and used for pain management) such as:

  • An allergic reaction (itchiness)
  • Nausea or vomiting
  • Hypotension (low blood pressure)
  • Drowsiness
  • Constipation
  • Respiratory depression (slow breathing, which is the most prevalent dangerous side effect of opioids)
  • Overdose of pain medications (according to a 2013 study, this most often occurs as a result of faulty machine programming/human error.)

Special Precautions When Using a PCA

While everyone who uses a PCA system should be monitored closely for side effects—such as respiratory depression—some people require even closer observation when taking opioids. These demographics include:

  • The elderly
  • Those with breathing disorders (such as asthma or other lung problems)
  • Those with sleep apnea
  • Those who are obese
  • Those who require high dosages of opioids to get pain relief

A Word From Verywell

When it comes to pain management, it is helpful to understand your options so you and your healthcare provider can make the best decision for your care. Speak with your healthcare provider and healthcare team to determine if you're a good candidate for a PCA system, which could improve your level of comfort.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Johns Hopkins Medicine. Patient-controlled analgesia pumps.

  2. McNicol ED, Ferguson MC, Hudcova J. Patient controlled opioid analgesia versus non-patient controlled opioid analgesia for postoperative pain. Cochrane Pain, Palliative and Supportive Care Group, ed. Cochrane Database of Systematic Reviews. doi:10.1002/14651858.CD003348.pub3 

  3. Michigan Medicine. University Of Michigan. Pain management: Patient controlled analgesia (PCA) pump.

  4. Yi Y, Kang S, Hwang B. Drug overdose due to malfunction of a patient-controlled analgesia machine -A case report-. Korean J Anesthesiol. 2013;64(3):272. doi:10.4097/kjae.2013.64.3.272

By Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.