Patient Controlled Analgesia (PCA)

Patient controlled analgesia (PCA) is a pain control system that allows patients to manage their own pain rather than wait for a nurse or other healthcare professional to give more medication. PCA uses a computerized pump that is hooked up to the patient’s intravenous line (IV) and lets the patient safely self-administer small doses of a prescribed opioid as needed for pain control. Several safety features exist with PCA to make certain patients do not receive too much analgesia. The portable device delivers a preset dosage with an adjustable “lock-out” that controls the frequency of dose administration and the maximum allowable amount during a specified time interval.

As the name implies, it is intended for the patient to control. The patient can receive the pain medication by pressing a button, allowing that individual greater control in managing the pain he or she is experiencing. The device provides a built-in safety check because an over-sedated patient is not able to push the button to cause a harmful or even fatal overdose. Patient-controlled analgesia bypasses the delays inherent in traditional analgesia administration (the demand cycle). Medication administered by IV produces a rapid pain response and greater consistency in patient response.

PCA is an effective and efficient method of controlling pain. When it is used as prescribed and intended the risk of over-sedation is significantly reduced; however, when a family member or healthcare professional administers PCA, serious adverse events can result. When family members, caregivers, or clinicians, who are not authorized, become involved in administering the analgesia for the patient it is called “PCA by proxy.”

According to a warning issued by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO), well-intended family members and caregivers who want to keep the patient from suffering may actually be putting them at risk by becoming involved in administering PCA. Over the past several years the Institute for Safe Medical Practices (ISMP) has issued a number of warnings and reports alerting healthcare organizations and practitioners to safety issues related to PCA by proxy. With PCA, the patient provides a measure of safety because the analgesia is delivered at doses lower than what is needed for sedation because an over sedated patient will not push the button to give additional opiate. Bypassing this built-in safety feature by proxy is potentially dangerous. PCA by proxy errors are readily preventable and can be virtually eliminated through appropriate education and training of staff and family members.

Nurse-controlled analgesia using a PCA infusion device may be useful in some critical care settings and offers advantages over traditional medication administration for pain management; but, protocols and appropriate assessment tools must be in place to gauge:

• level of pain
• sedation
• respiratory status (respiratory rate and oxygen saturation)
• reassess appropriateness of therapy

Take the case of a 45 year old who was hospitalized for major abdominal surgery. One of her daughters that had some medical training, but not specific to post operative medications, did not want her mother to suffer and began pushing the PCA button whenever her mother moaned or seemed uncomfortable. The well-intentioned daughter over sedated her mother so much that respiratory depression began to set in as evidenced by decreased oxygen saturation levels. While decisions were being made as to the need for intubation, it was identified that the daughter was pushing the PCA button rather than the patient. The patient was properly educated prior to surgery but family members were not warned of the risks of PCA by proxy.

Information from an ISMP safety alert describes a 72-year old woman who underwent cancer surgery and her surgeon prescribed PCA with a 2 mg morphine loading dose and 1 mg every 10 minutes as needed (6 mg maximum dose per hour). Initially, the patient was restless and agitated in the post anesthesia care unit, but she remained obtunded after surgery. Despite the patient’s ability to verbalize pain, nurses pushed the PCA button and delivered frequent doses of morphine over the next 48 hours. Subsequently, the patient suffered a cardiorespiratory arrest and seizure, leading to hypoxic encephalopathy. She died several months later without ever regaining consciousness.

Nurse-controlled analgesia was not appropriate in this case. The patient was not an appropriate candidate for PCA and proper assessment tools were not used as guides for nurse-controlled analgesia. The patient was at risk for toxicity because she was obtunded, obese, and had compromised lung capacity (COPD). Although vital signs were recorded periodically, oxygen saturation monitoring was not used. The nurses did not recognize the signs of morphine toxicity and they continued to administer the analgesic despite serious hypotension and very shallow respirations.

The most common PCA errors are usually the direct result of family members or healthcare professionals administering doses for the patient with the intent of keeping them comfortable. This well-intentioned effort can result in over-sedation, respiratory depression, and even death. The United States Pharmacopia (USP) and the Institute for Safe Medication Practices (ISMP) medication errors database revealed a combined total of 6,069 PCA errors. Of this number:

• 460 cases had some level of harm to patients including impairment of the physical, emotional, psychological function, or structure of the body resulting as a consequence of errors related to PCA.
• 5 of the 460 errors were fatal errors including one by proxy error attributed to a nurse
• Most of the errors were attributed to family members

The root-cause issues related to PCA errors are:

• Improper patient selection
• Inadequacy of monitoring
• Patient education,
• Drug product mix-ups
• Practice-related problems
• Device design flaws
• Inadequate Staff training
• Prescription errors

The Joint Commission offers the following safe practice recommendations:

1. Develop criteria for selecting appropriate patients to receive PCA and nurse controlled analgesia.
   
2. Carefully monitor patients. Even at therapeutic doses, opiates can suppress respiration, heart rate and blood pressure. Oximetry and/or capnography monitoring may be appropriate in some cases.
   
3. Teach patients and families about proper use of PCA. Provide written instructions to family members that instruct them NOT to administer PCA doses.
   
4. Alert staff to the dangers of administering a dose for the patient outside of a nurse controlled analgesia protocol.

ISMP Tips for prescribing PCA:

• Limit verbal orders to dose changes
• Always dose PCA opiates in mg or mcg, not by volume (ml)
• Check patient allergies before selecting the opiate used with PCA
• Use morphine as the opiate of choice
• Consider other medication that the patient has received (e.g. analgesics taken at home, intraoperative medications) or currently has prescribed (e.g. antihistamines, night-time sedatives) when determining the loading and maintenance doses
• Reassess the appropriateness of PCA therapy at regular intervals

Other Precautions:

• Educate staff and plan regular retraining to critically think about the cumulative dose that the patient could receive if the maximum dose limits were given
• Require two clinicians to independently double check patient identification and PCA doses settings prior to use and at each pump refill
• Develop and follow guidelines and standardized order sets for using PCA
• Place warning labels “For patient use only” on PCA buttons or equipment.
• Remind patients and visitors that the PCA is for patient use only and that visitors shouldn’t push the button even if the patient asks.
• Educate patient and visitors about PCA and tell them to notify a nurse if the patient seems overly sleepy.
• If a patient is difficult to arouse or has respiratory depression, assess his airway, breathing, and circulation; initiate basic life support as indicated and have someone notify the primary care provider.
• Educate patients regarding PCA during preoperative teaching.

PCA is an effective and efficient method of controlling pain, and when used as prescribed and intended, the risk of over sedation is significantly reduced. Some patients are not appropriate candidates for PCA because of age, mental state, level of consciousness, intellectual capacity, or other factors that require close monitoring of the delivery of pain medications. PCA by Proxy errors are usually the direct result of family members or healthcare professionals administering doses for the patient with the intent of keeping them comfortable. PCA by Proxy errors are readily preventable and can be virtually eliminated through timely and appropriated education for patients, family members, and staff caring for patients with PCA. The dangers of having others pressing the medication button needs to be understood by all involved in the care of the patient.

Hill, Charlene D. Joint Commission Issues Alert on Dangers of Family Members, Caregivers Delivering Patient Controlled Analgesia; JCAHO News Release (2004)

ISMP Medication Safety Alert! May 29, 2002, Institute for Safe Medication Practices

ISMP Medication Safety Alert! July 10, 2003, Institute for Safe Medication Practices

ISMP Medication Safety Alert! July 24, 2003, Institute for Safe Medication Practices

Joint Commission on Accreditation of Healthcare Organizations Sentinel Event Alert – Issue 33 – December 20, 2004

Maddox, R.R.; Williams, C.K.; Fields, M. Respiratory Monitoring in Patient-Controlled Analgesia, AM J Health-Sys Pharm 2004; 2628-9

Monitto, GL.; Greenberg, RS; Kost-Byerly, S.; Wentzel, R.; Billett, C.; Lebet, RM.; The Safety and efficacy of parent-/nurse-controlled analgesia in patients less than six years of age; Abstract Entrez PubMed – Clinical Trials (2005)

Murhammer, Joan; Ross, Mary; Bebout, Kevin; Patient-Controlled Analgesia: Review of Safety Issues: Rx Update: August 2003

Nettina, Sandra M. Lippincott Manual of Nursing Practice, 7th Ed. Lippincott, Philadelphia (2001)