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Fast Fact and Concept #92: Patient Controlled Analgesia in Palliative Care

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Title: Fast Fact and Concept #92: Patient Controlled Analgesia in Palliative Care

Author(s): Erik Prommer

Patient Controlled Analgesia (PCA) is the technique whereby patients can self administer parenteral analgesics. The primary advantage of PCA is to shorten the interval from patient-defined need, to the time of actual analgesic administration. PCA is an effective, safe and well accepted treatment for post-operative pain, sickle cell crisis pain (as young as age 4), and cancer pain. In general, PCA will provide the same degree of analgesia compared to other delivery systems with the same or less total amount of medication. PCA allows for more immediate relief of incident (breakthrough) pain and can provide patients with a greater sense of personal control over their pain.

Indications: The primary indication for PCA is the patient who requires parenteral analgesia (e.g. severe pain and/or oral/transdermal/rectal route not useable) and has incident pain or other pain patterns that are not predictable. PCA is also indicated for use as a method of rapid dose titration and dose finding in acute severe pain. Relative contraindications include patients who a) do not have the cognitive ability to understand how to use a PCA device, or b) have an anticipated need for parenteral opioids less than 24 hours.

PCA devices: most devices have a drug reservoir and infusion system whereby PCA administration can occur with or without a background continuous infusion. Thus, PCA devices need the following orders:
  1. PCA dose in mg or ug (aka Patient Initiated Dose or Patient Demand Dose)
  2. Delay Interval (aka Lockout) - in minutes (period during which the patient cannot obtain additional medication)
  3. Continuous infusion (CI) Rate in mg/hr or ug /hr (if CI is used)
  4. Hour Limit - Maximum amount of drug to be dispensed in a defined period of time; set the one hour limit to deliver 3-5 times the estimated required dose.
(Note: due to the need for frequent dose adjustments, the Hour Limit is often omitted in Palliative Care). Most palliative care patients will need both PCA demand and CI dosing. Opioids in PCA devices include morphine, hydromorphone, fentanyl and methadone. IV and SQ are the most common routes of administration; PCA can be used with epidural, intrathecal or intraventricular opioid administration. (see Fast Fact #28: Subcutaneous Infusions)

Dosing: Opioid naive patient: The following information is for Morphine, the drug of first choice for most patients. Note: Dosing and Delay interval information will differ with other opioids. Start dosing: PCA demand dose = 1-3 mg MS; Delay Interval = 8-10 min. The total dose given over 4 hours is calculated and an hourly rate determined (e.g. if 16 mg is given over four hours = 4 mg/hour). A new PCA demand dose is then calculated at 50% of the hourly continuous infusion rate (4mg/hr / 2 = 2 mg PCA demand dose, Delay Interval 8-10 min).

Dosing: Non naive patients: Convert the current total oral/transdermal dose to a total 24 hour IV dose; divide by 24 to give the hourly Continuous Infusion rate (mg/hour, IV/SQ). (See Fast Fact #36: Calculating Opioid Dose Conversions). The PCA demand dose is initially calculated at 50% of the hourly rate.

Risk of Overdose The patient who is pushing his or her own PCA button will fall asleep before serious signs of overdose occur as long as only the patient pushes the button (Special care is needed for patients with sleep apnea as they will be more sensitive to opioids).

Dose titration and Loading Doses: See Fast Facts:
Fast Fact #20: Opioid Dose Escalation
Fast Fact #54: Opioid Infusions in the dying patient
Fast Fact #72: Opioid Infusion Titration Orders

NOTE: these dosing recommendations are rough guidelines -- clinicians need to take into account patient age, renal and pulmonary function, co-morbid illness and other psychoactive medication. When in doubt, it is advised to use a lower continuous infusion rate (with upward dose adjustments of the CI rate no more frequently than every 8 hours), while adjusting the PCA dose at frequent intervals (q30-60 minutes).

References:
Bruera E., Ripamonti Carla. Current Status of Patient-Controlled Analgesia in cancer patients. Oncology 1997; 11: 373-384 1997
Citron ML.,. Ripamonti-Bruera article reviewed. Oncology 1997; 11: 384-386 1997.
Principles of analgesic use in the treatment of acute pain and cancer pain. American Pain Society 4th Ed. Pgs 39-43.
Pain Clinical Manual 2nd Ed. McCaffery M and Pasero C (eds) Mosby 1999.

Copyright/Referencing Information: Users are free to download and distribute Fast Facts for educational purposes only. Citation for referencing. Prommer, E. Fast Facts and Concepts #92 PATIENT CONTROLLED ANALGESIA IN PALLIATIVE CARE June 2003. End-of-Life Physician Education Resource Center www.eperc.mcw.edu.

Disclaimer: Fast Facts provide educational information, this information is not medical advice. Health care providers should exercise their own independent clinical judgment. Some Fast Fact information cites the use of a product in dosage, for an indication, or in a manner other than that recommended in the product labeling. Accordingly, the official prescribing information should be consulted before any such product is used.

Creation Date: 7/2003

Format: Handouts, Lecture Notes

Purpose: Instructional Aid, Self-Study Guide, Teaching

Audience(s)
Training: Fellows, 3rd/4th Year Medical Students, PGY1 (Interns), PGY2-6, Physicians in Practice
Specialty: Anesthesiology, Emergency Medicine, Family Medicine, General Internal Medicine, Geriatrics, Hematology/Oncology, Neurology, OB/GYN, Ophthalmology, Pulmonary/Critical Care, Pediatrics, Psychiatry, Surgery
Non-Physician: Nurses

ACGME Competencies: Medical Knowledge, Patient Care

Keyword(s): Addiction, Chronic non-malignant pain, Controlled substance regulations, Pain, Pain assessment, Pain treatment


The Fast Facts series is distributed for educational use only and does not constitute medical advice. For the most current version of Fast Facts visit the EPERC web site at www.eperc.mcw.edu. This mirror version is provided subject to copyright restrictions for educational use within the Inter-Instutional Collaborating Network on End-of-Life Care (IICN).