Patient Safety, Patient-Controlled Analgesics, PCA

Monitoring Technology for PCA Pumps Can Prevent Adverse Events with Patient-Controlled Analgesia (PCA): So Why Are Hospitals Not Using It?

By Michael Wong

(This article has also been published in SurgiStrategies, which can be read here.)

According to its newly-updated, “How-to Guide: Prevent Harm from High-Alert Medication”, the Institute for Healthcare Improvement (IHI) looked at high-alert medications, which are “more likely than other medications to be associated with harm”.

One of the areas that the IHI singles out is narcotics. The IHI guide points out the necessity and importance of narcotics in treatment:

Pain management is an important component of patient care. Implementing appropriate pain management protocols not only ensures that patients receive pain relief, but also minimizes opportunities for errors and harm. Effective pain control is integral to good health and to recovery from injury, surgery, and illness.

However, with this benefit may come the potential for harm. As the guide finds:

A review of costs associated with errors related to patient-controlled analgesia (PCA) and device related narcotic errors found that each error cost $552 – $733; harmful errors were 120 – 250 times more costly than those without harm. The authors estimated an annual rate of 407 PCA related and 17 device-related errors per 10,000 people in the United States.

However, adverse events with PCA pumps may occur even without an error being committed by attending healthcare professionals. As Frank Federico, RPh (Executive Director at IHI) points out, “Many patients may experience harm even with appropriate dosing of narcotics. This is a critical point for patients, their families and their caregivers to know — a patient may experience respiratory depression, leading to death, even if the PCA pump has been programmed correctly. Many believe that some of the adverse effects are the cost of doing business.  Our goal should be to reduce all harm, understanding that we may not know how to today. When a patient dies from respiratory depression, the toll on the patient’s family, friends, and community are enormous. The cost of adverse events goes beyond the costs associated with a medical malpractice claim.”

In their study, “Programming errors contribute to death from patient-controlled analgesia: case report and estimate of probability,” researchers determined that mortality from programming errors with PCA pumps was estimated to be a low-likelihood event (ranging from 1 in 33,000 to 1 in 338,800), but relatively high in absolute terms (ranging from 65 to 667 deaths). In other words, when harm from PCA occurs, it is likely to result in death.

Moreover, when PCA pump events were correlated against costs, quite understandably, non-harmful events were estimated to cost about $28 per event, but a harmful adverse event determined to be opioid related was $13,803 per event, as this study, “The Rate and Costs Attributable to Intravenous Patient-Controlled Analgesia Errors” showed:

As Rodney Hicks , PhD, APRN, FAANP, FAAN (Professor, Western University College of Graduate Nursing, Pomona, California), says, “Our study highlighted that IV PCA has a higher likelihood of errors, because of the complexity of IV PCA administration. Practitioners should capitalize on capnography and future innovations, such as linking monitoring alarms to the hospital’s network, to alert staff when a patient may be experiencing respiratory depression. Using such technology will realize potential cost savings or avert future costs associated with adverse events with PCA pump.”

Steps taken by Veterans Health Administration to avert PCA events echo these sentiments. As Bryanne Patail, biomedical engineer at the U.S. Department of Veterans Affairs, National Center for Patient Safety describes how VHA implemented a “strong fix” to reduce PCA-related events by more than 60%:

Use of PCA pumps is a process, and improving that process is an area that involves many stakeholders. In looking at fixes, they can be categorized as strong, intermediate or weak fixes. The strongest fix for PCA pumps is a forcing function, such as an integrated end tidal CO2 monitor that will pause the pump if a possible over infusion occurred. So, healthcare providers should first look at these strong fixes. There they will see the most impact on reducing errors and improving patient safety.

Moreover, I asked David Watson (VP at ECRI Institute) whether ECRI concurs with VHA’s recommendations. ECRI is an independent, nonprofit organization that researches the best approaches to improving the safety, quality, and cost-effectiveness of patient care.

Watson replied to me:

Infusion devices regularly appear within our Top 10 Technology Hazards list.  We cited PCA pumps within that list back in November 2010 in relation to the risks of oversedation and the associated potential for narcotic induced respiratory depression.  Infusion systems should be viewed as one component of a medication delivery system.  Other components within the process may include the need to ensure adequate monitoring is in situ.  In relation to this ECRI Institute is aware of previous studies suggesting that the concurrent use of pulse oximetry and capnography can lead to the early identification of respiratory depression. 

We have previously recommended the development of an action plan to implement effective physiological monitoring of patients on PCA therapy.  As such, I would concur with the VHA recommendations on this.

In short, we currently have the technology to catch and prevent many adverse events with PCA pumps. As Dr. Robert Stoelting (President, Anesthesia Patient Safety Foundation) explains:

Future technology developments may improve the ability to more effectively utilize continuous electronic monitoring of oxygenation and ventilation in the postoperative period.  However, maintaining the status quo while awaiting newer technology is not acceptable” [Dr. Stoelting’s emphasis].

Patient-Controlled Analgesics

Errors with patient-controlled analgesia (PCA): just the tip of the iceberg

by Michael Wong

Many readers emailed studies, suggestions, and comments regarding the estimate of 600,000 to 2 million PCA errors each year. These readers not only indicated the magnitude of the problem, but also a way to detect respiratory depression. Here are these further studies and thoughts.

Dr Richard Dutton (Executive Director, Anesthesia Quality Institute) “PCA errors certainly occur, both in programming and in delivery, but any published estimate is likely to be only the tip of the iceberg.”

First, regarding Professor Rodney Hicks’ rule of thumb that for every reported error, there are 300-1000 unreported instances, thank you Professor Hicks for supplying your unpublished dissertation, from which sources for his rule of thumb were given.

Although there have been a lot of studies on error reporting, probably the best two that support this estimate are:

  • On the lower end of 300, the study Kellier, N., Fitzpatrick, M., & Barach, P., “Analysis of adverse event reporting systems and geospatial mapping of Florida AHCA Code 15 data” Miami: Miami Center for Patient Safety (2004) provides that “near misses” reported to voluntary systems they studied “occur up to 300 times more often than events resulting in injury”.
  • On the upper end of 1,000, the study Flynn, E. A., “A brief history of medication errors” concluded that observation found 1,422 times the number of errors identified by spontaneous reports.

Second, corroborating studies provided by many readers shows how widespread is the usage of PCA. 0.1-1.0% of patients receiving PCA have serious respiratory depression, according to Dr. Richard Moon (Professor of Anesthesiology and Associate Professor of Medicine, Duke University Medical Center). In his presentation at the Anesthesia Patient Safety Foundation (APSF) workshop in 2006, Dr. Moon presented a talk entitled “Postoperative Pain Control and Respiratory Depression”, “Dr. Moon described how the fractal analysis of inter-breath intervals of these patients correlated with mean end-tidal CO2. He recommended that strategies to prevent opioid-induced respiratory depression should include patient triage, appropriate dosing, genetic screening (in the future), and bedside monitoring.”

When looking at the incidence of respiratory depression, Dr. Moon’s analysis is supported by the study by Dr Frank Overdyk (Professor of Anesthesiology and Perioperative Medicine at the Medical University of South Carolina) and his colleagues. This study found that when postsurgical patients undergoing PCA therapy were monitored with continuous oximetry and capnography, respiratory depression was identified in 41% of the patients. Moreover, as this study concluded:

Our incidence of RD by bradypnea is significantly higher than the 1%–2% incidence in the literature, using the same threshold criteria but more stringent duration criteria, while our incidence of RD based on desaturation is consistent with previous estimates. We conclude that continuous respiratory monitoring is optimal for the safe administration of PCA, because any RD event can progress to respiratory arrest if undetected.

Moreover, unfortunately, respiratory depression may be occurring with more frequency than most think. As Rob Hutchison (Associate Professor, Department of Pharmacy Practice, Texas A&M Health Science Center) says: “Respiratory depression occurs more often than most clinicians think with PCA.”

In a study led by Professor Hutchison, more instances of respiratory depression were detected in the capnography monitored patient group than the group without such monitoring:

In total, 146 episodes of respiratory depression were detected during the 36 hours on the general care nursing unit: 140 in the capnography group and six in the control group. All of these episodes were detected because the patient either took six or fewer breaths per minute or had an episode of apnea lasting longer than 20 seconds. Seventeen patients (15 in the capnography group and two in the control group) accounted for all episodes of respiratory depression. Pauses in breathing while sleeping, an indicator of OSA [obstructive sleep apnea] risk, were detected in the capnography group at twice the rate as in the control group (48% and 24%, respectively).

Capnography, Monitoring Liability and Costs, Patient Safety, Patient-Controlled Analgesics, PCA

How often do errors with patient-controlled analgesia (PCA) occur?

by Michael Wong

Many readers of this website have asked, how often do errors with patient-controlled analgesia (PCA) occur?

In a retrospective analysis lead by Rodney Hicks (who at the time of the study was Manager, Patient Safety Research and Practice, United States Pharmacopeia), the magnitude, frequency, and nature of non-harmful and harmful medication errors associated with PCA were studied. (Professor Hicks is now Professor, Western University College of Graduate Nursing, Pomona, California).

Over the five-year review period, of the 919,241 medication errors records from the 801 reporting healthcare facilities, just 1% (or 9,571) were associated with PCA. Although 1% may seem insignificant, this analysis was based on the voluntary medication error reporting program, MedMarx.

“Although generalization of voluntary reported findings to the general population should be done cautiously,” as Professor Hicks points out, “The general rule of thumb is that for every reported event, there can be between 300-1,000 unreported events.”

Using this rule of thumb, based on 9,571 reported events, this would mean that between 2.8 million and 9.6 million total events (unreported & reported) occurred over the five-year period from July 1, 2000 to June 30, 2005. On an annualized basis, this would mean that about 600,000 to 2 million events per year could involve PCA.

“A further study would need to be done to ascertain the total number of PCA events,” explains Professor Hicks, “but the problem is extensive in my opinion.”

Moreover, when the study looked at the number of events that caused harm, there were 624 records of PCA associated with harm, corresponding to 6.5% of the patients. Again, while 6.5% may seem small, as the study found, “By comparison, during the same period, only 1.5% of all other errors reported to MedMarx led to harm. This represents a fourfold higher relative risk of harm for PCA events.”

“All health care disciplines were implicated in the errors, including physicians, pharmacists, and nurses” Hicks reported.  “Therefore, it will take an inter-disciplinary team to resolve the problems”.

As Professor Hicks concludes:

Our analysis was in no means trying to discourage the use of PCA pumps. Many studies have shown the benefits of using PCA, including improved pain management, better utilization of nursing resources, increased patient satisfaction, and improved pulmonary function.

However, this is clearly an area that standardization needs to occur and organizations need to invest in training and policies and procedures as well as equipment – all areas to promote safety.

Moreover, although elimination of error is critical, studies have shown even a correctly programmed PCA pump poses patient safety risks. In their study, “Continuous Oximetry/Capnometry Monitoring Reveals Frequent Desaturation and Bradypnea During Patient-Controlled Analgesia”, Dr. Frank Overdyke and his colleagues point out, “The most serious complication of patient-controlled analgesia (PCA) is respiratory depression (RD).” They found that:

continuous respiratory monitoring is optimal for the safe administration of PCA, because any RD event can progress to respiratory arrest if undetected.

As Ray Maddox and his colleagues point out in their study “Intravenous Infusion Safety Initiative: Collaboration, Evidence-Based Best Practices, and ‘Smart’ Technology Help Avert High-Risk Adverse Drug Events and Improve Patient Outcomes”:

Even correctly programmed, appropriate doses of opiates can suppress respiration and decrease heart rate and blood pressure. Episodes of bradypnea and desaturation can escalate to respiratory depression (RD) requiring rescue. The success rate for in-hospital cardiopulmonary resuscitation remains less than one in five patients. If detected early, most cases of opioid-induced respiratory depression can be treated with naloxone. However, severe cases can be fatal.The risk of patient harm due to medication errors with PCA pumps is 3.5-times the risk from any other type of medication administration error.

These researchers therefore recommend:

Capnographic monitoring—measurements of ventilation using respiration and exhaled carbon dioxide (EtCO2)—is particularly important because it can provide an earlier warning of respiratory depression than pulse oximetry (SpO2) in some patient populations.

What do you think? Are you aware of any other studies that have looked at PCA error incidence rates?