Programmable patient-controlled analgesia (PCA) pumps work safely for the vast majority of patients, but medication errors can and do happen with these devices. Here are five strategies to help you purchase, prescribe, dispense, program and initiate these devices with patient safety in mind.
Select pumps with care
Programming a PCA requires several steps. Clinicians must separately program the
- loading dose,
- the continuous infusion and mini-bolus doses, and
- the lockout interval (which disables the patient-control button so the patient can't deliver a bolus for a predetermined time after the previous one).
Some pumps lack a user-friendly, intuitive design, which can lead to an error during any of these steps. The most common - and sometimes fatal - programming errors happen when the concentration settings for opioid medications default to 0.1mg/mL or 1mg/ML, but a higher concentration is available and accidentally programmed by the clinician. There are also PCAs that don't require clinicians to review all programmed settings before infusion starts and pumps that program doses in mL, rather than mg, both of which may lead the clinician to overlook the amount of drug actually delivered.
Though quite rare, mechanical errors are possible. Free-flow errors caused by fractured glass syringes, which can entrain air into the body, have been reported. Free flow may also happen when a cassette breaks and detaches from a pump lacking anti-free-flow tubing.
Some common design flaws are related to the patient's use of the pump. First, many devices lack an auditory or visual feedback mechanism; if lockout intervals are set, patients might not be able to tell if their button pushing has had any effect. The result is that some patients press the button more frequently than they would if given proper feedback. Others become frustrated, give up and end up undertreating their pain. Another problem: The control button on some PCAs looks like the nurse-call button. Patients in PACU and hospital inpatient rooms can give themselves a medication spike when they want to call the nurse.
The FDA requires pump manufacturers to perform human-error testing in addition to delivery efficacy testing, but the former is loosely regulated and it's clear front-line practitioners and patients were not deeply involved in pre-market testing of many of these devices.
Before you buy a PCA pump, answer these questions:
- Can clinicians easily program the pump to deliver the desired drug concentrations? Are the controls ergonomic? Could a decimal point easily be moved and escape notice?
- Could unsafe administration sets accidentally allow free-flow?
- Do the drugs, delivery units and strengths appear in a logical sequence?
- What are the default settings for the opioid concentrations? (Preferably, zero is the default setting.)
- Does the pump require a double check before it'll work?
- Is pump operation intuitive?
Limit the number of different PCA pumps you use (see "Pain Pump Round Up" on page 56). If possible, obtain consensus on a single model the clinicians trust and stick with that device. This is desirable both from an economic and safety standpoint. Not only will you save time and money dealing with one distributor, using a single device facility-wide promotes programming proficiency, minimizes error potential and expedites the time clinicians need to correctly program the pump.
Establish PCA privileging
Take the time to teach nurses (and, in hospitals, pharmacists) how to program your pain pumps. Require clinicians who prescribe, dispense or initiate PCAs to undergo a privileging process; follow up yearly.
Train staff close to the time they'll actually use the pump. Mandate practice sessions to increase and maintain proficiency. Work with surgeons and anesthetists to design standard order sets to guide drug selection, doses, lockout periods and patient-monitoring protocols. Test personnel on these sets using the pump's programming sequence to reduce error risks.
Run simulations in which a selected clinician purposely writes an incomplete order, selects an incorrect drug or dose, makes a programming error, overlooks double-checking or forgets a critical monitoring point. See if the test-takers spot these. PCA-privileged nurses should also be able to recognize signs of opioid toxicity, assess patients with minimal verbal or tactile stimulation and distinguish between over-sedation and other complications; at minimum, they should evaluate the patient's pain level, alertness and vital signs (including respiration rate and quality).
Develop patient-selection protocols
Exercise caution before entrusting patients to manage pain with a PCA. Patients must have an appropriate level of consciousness and cognitive ability to operate a PCA; pediatric and confused adult (most commonly elderly) patients are contraindicated.
You may limit or heighten your monitoring requirements for patients at heightened respiratory depression risk, including obese patients, those with pre-existing conditions such as asthma or sleep apnea, and patients taking concomitant medications that potentiate opiates. Determine whether you can meet the increased monitoring level, including the availability of capnography or an overnight apnea alarm.
Conduct patient PCA education pre-operatively so you're not dealing with someone too groggy to understand instructions and ask questions. Warn the patient and family members that the devices are intended for the patient's use only. Reinforce this point by placing a "for patient use only" warning label on the pump's activation button. No device can guard against PCA-by-proxy (a third party pushing the button to deliver a mini-bolus), and oversedation and death have resulted from well-meaning family members (or staff) pushing the button for a patient who seems uncomfortable.
Follow medication and clinical best practices
The patient-controlled nature of PCA pumps heightens the imperative to establish good pharmacy and clinical initiation and monitoring standards. Create and adhere to a system of independent double-checks, even if it's for all settings. Follow these best practices:
- Check patient allergies before selecting a drug, before programming the pump and before initiation.
- Set maximum dose limits for PCA drugs in the pharmacy computer so an alert appears if an order entry exceeds safe limits.
- Use pumps that dose in mg or mcg, not only by volume (mL).
- When setting loading and maintenance doses, consider other meds given to the patient, such as oral analgesics, and medications the patient takes (such as antihistamines).
- Separate easily confused meds and take appropriate labeling precautions (such as "tall man" lettering differentiating HYDROmorphone from morphine).
- Use pre-filled syringes, bags or cassettes whenever available commercially. If not, have the pharmacy prepare the PCA medication.
- Finally, require two clinicians to independently double-check the original order patient ID, drug and concentration, pump settings and line attachment before initiation, program change or refill.