PCA is intended to be patient-controlled analgesia. Probably the most tragic error or event associated with PCA involves what is referred to as PCA by proxy, where someone other than the patient presses the button to inject a dose of pain medication into the patient.
A very important safety feature of PCA is that patients who are oversedated from having received too much opiate will not be able to press the button to obtain additional doses of the drug. This safety feature is overridden if someone else pushes the button for them.
Family members may believe that they are helping the patient remain pain-free by pushing the button for them. When other individuals push the PCA button, they may seriously misjudge the patient’s level of sedation, resulting in extreme oversedation, respiratory depression, and potential respiratory arrest. Like many medication errors, the exact incidence of PCA by proxy is unknown. The difficulty in determining an overall frequency of the problem is that the numerator and denominator are not known because the exact number of PCA prescriptions is not available. However, it is clear that this practice has led to fatal incidents.
ISMP has investigated several error reports involving PCA, including one involving an otherwise healthy teenage girl who died when her PCA button was pushed continuously by her mother. As a result of incidents such as this, there has been a call for action regarding PCA by proxy.
At a minimum, there should be hazard warnings on the PCA equipment to caution family members and even health care practitioners about the dangers of PCA by proxy. Family members and medical staff should also be provided with education and training on proper PCA use. PCA by proxy may be legitimately used by nurses in certain situations, but it is probably more appropriate to call this practice nurse-assisted analgesic dosing.
Nurse-assisted analgesic dosing can be used safely when the healthcare professionals involved are authorized, properly educated on pain assessment and opioid toxicity, and required to follow a protocol. Unauthorized PCA by proxy involving a spouse, family member, or friend is far more likely to result in patient harm. When other individuals push the PCA button, they may seriously misjudge the patient’s level of sedation, resulting in extreme oversedation and respiratory depression. by proxy situations may be more controversial, such as when parents control the administration of the drug by pushing the button for their child. Many children can be taught to use PCA, and although healthcare organizations may elect to have an age limit for this method of pain management, each case should be evaluated individually. Hospitals should develop policies and procedures to address family and nurse administration of PCA.
Safe Practice Recommendations: ISMP urges all healthcare facilities that provide PCA for patients to reassess their current safeguards around this mode of pain management to ensure adequate prohibition of PCA by proxy and patient monitoring to quickly detect and correct signs of opioid toxicity. Perhaps over the years, the initial steps taken to prevent tragedies associated with PCA by proxy may no longer be rigorously applied.
Patient selection criteria
Assess current policies and practices regarding the proper selection of patients for PCA use. Stringent patient selection criteria for PCA may be included in protocols and order sets to support candidates who have the mental alertness and cognitive, physical, and psychological ability to manage their own pain, but the criteria may no longer be followed or enforced. The benefits of PCA, along with a lack of current reports of harm from PCA by proxy, may have led providers over the years to extend its use to less than ideal candidates who require practitioner-initiated PCA doses, including infants, young children, confused or incapacitated patients, or other inappropriate candidates such as patients on additional drugs that potentiate the effect of opioids or contribute to respiratory depression. Since an important safety feature with PCA is that the patient delivers each dose, proper patient selection is critical. (Also, The Joint Commission requires adherence to established patient selection criteria for PCA therapy, and the Centers for Medicare & Medicaid Services [CMS] Conditions of Participation require a documented assessment of the capacity of the patient to successfully administer any self-administered medications.)
Review current policies and practices related to patient monitoring during PCA use to determine their effectiveness in identifying and acting upon respiratory insufficiency to avoid patient harm. The Anesthesia Patient Safety Foundation (APSF) suggests continuous monitoring using pulse oximetry as well as capnography to detect unrecognized hypoventilation and carbon dioxide retention (www.apsf.org/newsletters/html/2011/fall/pdf/fall_2011.pdf). APSF recommends the use of pulse oximetry to detect hypoventilation when supplemental oxygen is not being used. For patients receiving supplemental oxygen, monitoring ventilations with capnography is necessary to provide an additional measure of safety. Because oversedation has occurred in patients with certain comorbid conditions such as pre-existing respiratory disease, obesity, and sleep apnea, or when using concurrent drugs that potentiate opioids, an effective screening process is also necessary to identify these risk factors and, if PCA is still used, to employ extra safeguards including capnography. Also be sure that any alarms in use (e.g., pulse oximetry, capnography, apnea alarms) are recognized and responded to appropriately and in a timely manner—an unheard alarm or lack of response due to alarm fatigue can be deadly.
Educate patients and staff
Despite widespread awareness in the past about PCA by proxy, don’t assume this is an old problem that has been resolved. Ensure that all patients, family members, and new staff who work in clinical units are educated about this potential knowledge gap. Patient education should not take place in the post-anesthesia care unit but rather before surgery while the patient is alert. If family members or clinical staff feel the patient is not receiving adequate pain relief with PCA, the patient’s physician should be notified to determine if a different form of analgesia is needed for the patient.
Assess the need for warning signage
Assess whether warning signs are necessary on PCA cords to alert family members and remind staff that PCA doses should be administered only by patients. If used, be sure the warning is clear and understandable to patients, family members, and staff (e.g., WARNING: BUTTON TO BE PRESSED ONLY BY THE PATIENT).