Patient Safety Tip of the Week

September 6, 2011    More Tips on PCA Safety



In our January 4, 2011 Patient Safety Tip of the Week “Safer Use of PCA” we focused on safety issues related to patient-controlled analgesia (PCA) and the issue of opiate-induced respiratory depression in general and provided a list of recommendations for improving PCA safety that we will repeat at the end of today’s column. And in our May 17, 2011 Patient Safety Tip of the Week “Opioid-Induced Respiratory Depression – Again!” we encouraged hospitals to perform their own FMEA (Failure Mode and Effects Analysis) on the PCA process and provided links to two tools we use when doing FMEA’s of the PCA pump process: the PCA Pump Audit Tool and the PCA Pump Criteria. One other valuable resource we should have pointed out to you is a sample FMEA by ISMP for PCA.


In the January column we cited an excellent article on a McMaster University safety initiative to reduce PCA errors (Paul 2010) that stressed several key elements: smart pumps with both “hard” stops and “soft” stops, user-interface for programming the pumps that allowed visualization of all key parameters on one screen, pre-printed order forms, CPOE, independent double checks, review of all PCA program settings during each shift and on shift handovers, a rigorous program of education and training for nurses, and a mandatory critical incident reporting program.


One of the issues we have always included in our FMEA’s is that of training, retraining, and competency assessments for all providers who will be involved in use PCA pumps. Obviously, standardizing the pumps to be used and restricting drugs that can be used and standardizing drug concentrations are important first steps. But you still need to ensure that all your staff understand fully the intricacies of PCA pumps. One hospital system, after recognizing an increase in frequency of incidents related to PCA pumps, combined quality improvement efforts with their staff development program to reduce PCA errors (Ferguson 2010). They mandated training for all RN’s who use PCA pumps and did the training at a time and location away from direct patient care responsibilities. The format was standardized to include a 30-minute lecture and 30 minutes of hands-on time to practice programming the pumps. They then had to return and demonstrate their ability to properly program into the PCA pump a preprinted order set and also complete an online module and post-test. Training over 900 nurses, they found that the number of PCA programming errors went from 8 down to 1 over a comparable time period.


This month’s Pennsylvania Patient Safety Advisory (Ritter 2011) has an article summarizing PCA errors found in the PPSA database and FDA’s MAUDE database. Not surprisingly, pump programming errors head up the list. They highlight such issues as the counterintuitive one in which programming the pump with a drug concentration that is too low actually results in overdosing the patient. Look-alike/sound-alike (LASA) errors are not uncommon and failure to perform independent double checks was also common. And many of the cases of respiratory depression noted were in patients receiving other drugs capable of depressing respiration in addition to the PCA opiates. They provide several useful recommendations, including the importance of proper patient selection for PCA but caution that even with proper selection patients may react differently to the same dose of opiates. They also discuss prescribing errors, drug product mixups, and PCA by proxy. They provide good discussion on use of standardized protocols and have a very good section on monitoring.


We have stressed the problems with monitoring patients receiving opiates on multiple occasions. We’ve noted several times the excellent article by Lynn and Curry  (Lynn 2011) on alarms and their failure to identify deteriorating patients early, highlighted in our February 22, 2011 Patient Safety Tip of the Week “Rethinking Alarms”.


The APSF (Anesthesia Patient Safety Foundation) has just released a summary of their “Conclusions and Recommendations from June 08, 2011 Conference on Electronic Monitoring Strategies to Detect Drug-Induced Postoperative Respiratory Depression”. They again make a cogent argument for continuous physiological monitoring of all patients receiving post-op opiates, including continuous pulse oximetry (and capnography for all patients receiving supplemental oxygen). And though they note the importance of identifying patients with conditions that place them at higher risk of respiratory depression, they note that selective monitoring of these would miss respiratory depression in patients without these risk factors. They again make the case that threshold-based alarm systems remain problematic and stress the need for systems that allow for earlier recognition of respiratory depression.


One development we consider exciting in the field of monitoring is an apnea prevention device (Zornow 2011). The author developed a device that takes input from a pulse oximeter into a laptop computer that has algorithms to identify episodes of oxygen desaturation, and delivers a series of stimuli to the patient (first verbal, then cutaneous stimuli via a nerve stimulator) to stimulate breathing. The device was tested in 10 extubated patients in a post-anesthesia care unit (PACU) who were at high risk for respiratory depression (known sleep apnea, morbid obesity, smokers, patients expected to need large doses of narcotics, etc.). Success of the intervention was defined as the patient taking a large tidal volume breath followed by an improvement in oxygen saturation. A total of 125 interventions occurred in the 10 patients with an overall success rate of 97%. Actually, though verbal stimuli occasionally failed, electrical stimuli followed by verbal stimuli were always successful. The author also looked at a subset of 5 patients to compare the number of required nursing interventions to stimulate respiration with the apnea prevention device turned on or off. He found patients needed a nursing respiratory-related intervention on the average every 2.3 minutes with the device off and only every 47 minutes with the device on.


This was just a proof of concept study but it is very promising. Obviously a large randomized controlled study needs to be done. But the author is already planning further enhancements to the device, such as adding input from a respiratory movement sensor, capnometers, etc. plus improvements to allow use of the device on wards as opposed to PACU’s. He’s even considering a feedback loop that will automatically prevent a PCA pump from delivering further doses of narcotics once certain thresholds are exceeded. The author has also recognized that the response parameters must balance the number of false alarms vs. the number of conditions truly needing an intervention and is planning all the outcome variables that will need to be tracked, including unintended consequences.




So, again, here is what your organization should be doing:




PCA is a great therapeutic intervention that has lots of positives but it also has its downsides and risks that your must try to minimize.




Other Patient Safety Tips of the Week pertaining to opioid-induced respiratory depression and PCA safety:








Paul JE, Bertram B, Antoni K, et al. Impact of a Comprehensive Safety Initiative on Patient-controlled Analgesia Errors. Anesthesiology. 113(6): 1427-1432, December 2010



ISMP (Institute for Safe Medication Practices). Example of a Health Care Failure Mode and Effects Analysis for IV Patient Controlled Analgesia (PCA). 2005



Ferguson R, Williams ML, Beard B. Combining Quality Improvement and Staff Development Efforts to Decrease Patient-Controlled Analgesia Pump Errors. Journal for Nurses in Staff Development – JNSD 2010; 26(5): E1-E4  September/October 2010.



Ritter HTM (Pennsylvania Patient Safety Authority). Making Patient-Controlled Analgesia Safer for Patients. Pa Patient Saf Advis 2011 Sep; 8(3): 94-9



Lynn LA, Curry JP. Patterns of unexpected in-hospital deaths: a root cause analysis. Patient Safety in Surgery 2011, 5:3 (11 February 2011)



APSF (Anesthesia Patient Safety Foundation). Conclusions and Recommendations from June 08, 2011 Conference on Electronic Monitoring Strategies to Detect Drug-Induced Postoperative Respiratory Depression. 2011



Zornow MH. Clinical Testing of the Apnea Prevention Device: Proof of Concept Data. Anesth Analg 2011; 112:;582-586

















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