Patient Safety Tip of the Week
February 12, 2013
CDPH: Lessons Learned from PCA Incident
PCA (Patient
Controlled Analgesia) safety has been one of our most frequent topics. Serious
incidents related to PCA continue to occur frequently. Another case with some
valuable lessons learned comes from the California Department of Public Health
(CDPH
2012).
In that case an
opioid-naďve patient received an estimated total dose of 67.8 mg of morphine
over an 8-hour period via PCA following a surgical procedure on his heel. He
was found unconscious and not breathing at 3AM and could not be resuscitated.
There were multiple
lessons learned in this case. The most obvious one is the total opioid dose
in a patient who was apparently opioid-naďve. The patient had a surgical
procedure on his heel from 2:15 PM to 6:50 PM. The PCA order, written by a CRNA
in the PACU, was for 3 mg morphine per injection with a lockout interval of 10
minutes and a basal rate of 1 mg morphine per hour. The PCA computerized log
showed that a total of 20 injections were given plus the basal infusion between
7:10 PM and 3 AM when the patient was found unresponsive and not breathing. The
last self-administered dose had been given at 1:27 AM.
Generally in
opioid-naďve patients we would begin with a much lower starting dose of
morphine and titrate upward as needed for pain control. Also we avoid basal
infusions in opioid-naďve patients.
The other obvious
problem in this case had to do with lack of appropriate monitoring. The
patient was apparently monitored via the medical-surgical post-operative
protocol and not monitored via a PCA protocol or policy. It appears the patient
was evaluated by nursing every 30 minutes for the first hour on the med/surg
floor, then hourly until midnight. There was another nursing evaluation at 2:00
AM. The last evaluation (when the patient was found unresponsive and not
breathing) was about 3:00 AM and apparently the nurse entered the patient’s
room to check on him because the patient could no longer be heard snoring. The
monitoring apparently included blood pressure, pulse, respirations, pain level,
and level of arousal. The patient’s oxygen saturation was not monitored (pulse
oximetry equipment apparently was available in the room but not utilized). It
also does not appear that electrocardiographic monitoring or capnography were
used. Note also that it is not clear in the report what specific monitoring
parameters had been ordered.
But those are only
the more proximate causes in this case. The root causes are much more
revealing.
It appears that numerous
providers were unfamiliar that the hospital even had a PCA policy. The CRNA
who wrote the PCA orders was not familiar with the hospital PCA protocol. The
surgeon stated he does not write PCA orders and that all he wrote was “pain
control per PCA” and that anesthesia took responsibility for initiating it. An
RN and a CNA taking care of the patient on the med/surg unit were both
unfamiliar with the PCA policy. Despite everything that has been written about
PCA safety issues we still find that hospitals underappreciate the potential
dangers and don’t put the appropriate policies, procedures, monitoring and
education in place to prevent adverse events related to PCA.
The relatively high
dose of morphine being administered by PCA in this case also was not questioned
by the pharmacists at the hospital. We certainly recommend that all hospitals
have dosage range limits for their high alert drugs that trigger alerts
when an ordered dose falls outside those set limits. Sometimes, however, such
limits are set wide to accommodate doses sometimes given. For PCA those dose
limits might be set high for opioid-tolerant patients, who might need a dose as
high as used in this case. They key is having a trigger that forces the
pharmacist to verify whether the patient is opioid-tolerant or opioid-naďve.
The easiest way to do that is to have a required field on a standardized order
set for PCA (computer-based or paper-based) that makes the ordering provider
state whether the patient is opioid-tolerant or not. However, because a
provider might bypass such order set you still need a flag for the pharmacist
to verify that status. (Note also that this really should apply to opioids
administered via any route, not just PCA.)
PCA pump setup is
one procedure that should require an independent double check by
nursing. Though we’ve written a lot about both the pros and cons of the
independent double check, when dealing with high alert medications it probably
does not hurt to have another set of eyes that might say “hey, I think the dose
of this drug might be too high”. It’s not clear if an independent double check
was done when the PCA was set up in this case.
The CDPH
investigation and hospital RCA/POC also mention several other items that bear
comment and there are other potential contributory factors we’ll speculate
about.
The policy at the
hospital in this incident did apparently require nursing to verify that the
patient’s cognitive function was adequate to understand and participate in the
PCA process. Confusion or impaired cognition are clearly contraindications to
PCA. However, we also feel there are several other relative contraindications.
These include sleep apnea, COPD, severe neuromuscular weakness, skeletal
conditions that may restrict respiration, and others. Perhaps the most
important consideration in this case would be sleep apnea. We know from
the report that the patient was obese and loud snoring was heard on several
occasions. So it is a distinct possibility this patient may have had sleep
apnea and we’ll comment on that further below. That is one of the reasons we
advocate use of a screening tool for sleep apnea, such as the STOP-Bang
questionnaire, in all patients undergoing surgery. If such a tool suggests
that sleep apnea is likely, we recommend special precautions if opioids are
administered via any route (eg. continuous monitoring in an ICU or stepdown
setting).
Who should be able
to order PCA? In this case the order was written by a CRNA. It is not clear in
the report whether or not that CRNA was part of a pain management team that
would be following the patient throughout the hospitalization. If not, wouldn’t
it make more sense if the order were written by a physician who would be
following that patient on an ongoing basis? Who would nursing call if a
question arose at night related to the PCA (the surgeon or the CRNA?)? Quite
frankly, we actually recommend that providers should require specific hospital privileges
to order PCA. Just as we privilege providers to do moderate sedation, those
desiring to use PCA should undergo appropriate educational sessions and be
certified to order PCA. We’ve simply seen too many errors related to PCA to
allow all providers to order PCA without knowing they are proficient in doing
so.
The orders for PCA
depend on whether the patient is opioid-naďve or opioid-tolerant. That
is an issue often neglected in writing the order for PCA, as it apparently was
in this case. Using a standard order set (paper or computer) is a good way to
force attention to opioid tolerance level. But that still is only good if the
provider uses that form. In the current case a standard order form is alluded
to in the hospital policy but it was obviously not used in this case.
Monitoring patients on PCA remains problematic. Any form of monitoring that is intermittent is
obviously very risky. Pulse oximetry is recommended for all and it should be
continuous pulse oximetry. But we’ve warned many times in the past that pulse
oximetry may also provide false reassurances. Opioid-induced respiratory
depression leads to hypercarbia before significant hypoxemia occurs. That is
especially true in patients who are receiving supplemental oxygen (so
supplemental oxygen should be used with caution in patients on PCA).
Patients on PCA (or
receiving opioids via other route) may have normal ventilation and oxygenation
when you arouse them (as opposed to what happens when they are sleeping). So if
you only check their pulse oximetry when you arouse them you will almost never
document hypoxemia.
Capnography has really now become the standard of care for avoiding post-operative opioid-induced respiratory depression and has been endorsed by numerous specialty organizations. However, a recent article does point out that the capnorgraphy used in unintubated patients is sidestream capnography and this is not particularly good for detecting hypercarbia (ASGE Technology Committee 2013). However, it can be used to monitor the respiratory rate and detect apnea and both of those are critical to monitor in the post-op patient on opioids.
Back to the issue of
possible sleep apnea. Apparently no one was bothered by the loud snoring
in the case at hand. Particularly in an obese patient it should have been a red
flag that this patient might have had sleep apnea. Opioids in patients with
sleep apnea may not cause the typical picture we associate with CO2 narcosis,
i.e. a progressive hypoventilation resulting in CO2 retention. Rather, patients
with sleep apnea undergo periodic hypoventilation broken up by “arousals”.
Eventually the opioids blunt the ability to have physiological arousals and
that is when deaths result.
This patient was described as being “arousable” at 2AM and was apparently alert enough to self-dose with the PCA pump at 1:27AM. That suggests to us this was not simply a case of opioid-induced CO2 narcosis. Rather, it suggests the third pattern of unexpected in-hospital death described in the excellent article by Lynn and Curry (Lynn 2011) on alarms and their failure to identify deteriorating patients early. Our February 22, 2011 Patient Safety Tip of the Week “Rethinking Alarms” highlighted that article in which they describe 3 patterns of unexpected in-hospital deaths and demonstrate the problems with threshold-based alarms (almost all currently used alarm systems use threshold-based principles) in detecting early deterioration. Indeed, they posit that threshold-based alarms themselves often cause us to miss signs of early deterioration.
The second pattern of deterioration they describe is the classic CO2 narcosis. As CO2 rises one sees further central depression of respiration and a vicious cycle. It is notoriously difficult at the bedside to predict who is hypoventilating. This is a pattern for which we have advocated using a combination of sedation scales and capnography. However, the authors point out that even such monitoring may be inadequate because many of these cases are complicated by the third pattern described below. The important point is that there may be a huge difference when the patient is awake and when he/she is asleep.
The third pattern they describe is one that is typically seen in sleep apnea. In this pattern one sees repetitive reductions in airflow and oxygen saturation during sleep followed by arousals. The arousals rescue the patient but eventually the capacity or reserve of the patient to recover with arousals becomes impaired (often in response to narcotics or sedatives) and the patient may experience sudden death during sleep. The authors discuss the inability of currently used oximeters to recognize this pattern. They even imply that this pattern may give rise to oximeters alarming and being interpreted as “false” alarms attributed to motion artifact, etc. because when staff respond to the alarm the patient is now awake, breathing normally and has a normal oxygen saturation.
See the list of our
previous columns on sleep apnea in the perioperative period at the end of
today’s column.
Education at
several levels is imperative. At the medical staff level we’ve already
mentioned our recommendation about requiring specific privileges to order PCA
and having them have appropriate training prior to granting those privileges.
At the nursing level all staff should receive inservices on PCA and be required
to demonstrate competency on PCA annually.
At the patient level
there are several considerations. When PCA was set up in the PACU nursing noted
that PCA was explained to the patient and questions were answered. It is not
clear what the patient’s capability of understanding was at that time since he
may well have had residual effects from anesthesia and other medications given
during and immediately after his surgery. Patient education should begin before
the day of surgery, either in the surgeon’s office or at a pre-op visit, and
should include both verbal and printed materials. Such education should also be
given to any family members likely to be with the patient in the hospital.
And there is also
the issue of education at the family level. It is also not clear whether any
education was provided to family members in this case. The report does state
that the patient’s wife left around 11PM or 12AM so she should have received
education about the PCA process. Because of the well-known problem of “PCA by
proxy” (where family or others push the PCA button to administer analgesic) it
is imperative that family and visitors be educated not to manipulate the PCA
pump in any way. We also recommend specific signage be affixed to the PCA pump
to warn family and visitors not to manipulate the pump.
Communication and handoffs are critical in most incidents that result in patient harm and this case
is no different. In this case there was an apparent handoff from one CRNA to
another CRNA. Did the second CRNA have adequate knowledge of the patient’s
history and current status? We don’t like to see any of the key players in
surgery (physicians, residents, nurses, surgical techs, anesthesiologists,
CRNA’s) change in the middle of a procedure. Scheduling and timing of cases
should take into account the need to maintain a full complement of personnel
through the entire procedure.
And there was a
handoff from the PACU nursing staff to the nursing staff on the med/surg floor.
Were any standardized handoff tools used? We recommend that PCA be a specific
item that needs to appear on such nursing handoff tools.
And there are other
potential contributing factors we cannot adequately assess from the CDPH
report. For example, the surgical case was of fairly long duration and ended
around 7PM. We don’t know if ending that late in the day put any time
pressures on staff. For example, was there any pressure to move the patient
from the PACU to the med/surg floor so the PACU staff could go home? Did the
timing and/or duration of the case have anything to do with the change in
CRNA’s noted above?
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. And we hope that you’ll go back and look at the string of recommendations we made in our September 6, 2011 Patient Safety Tip of the Week “More Tips on PCA Safety”. We think you will find them extremely helpful. And don’t forget that most of the issues pertaining to patients on PCA pumps apply also to patients receiving postoperative opioids by other routes.
And in our October
2012 What’s New in the Patient Safety World column “Another
PCA Pump Safety Checklist” we mentioned that the Physician-Patient Alliance
for Health & Safety (PPAHS) had a workgroup
addressing PCA safety. On their website are some heart-wrenching stories
about patients who died during PCA, likely as a result of inadequate
monitoring. We noted they had just released
a checklist for PCA pump safety (PPAHS
2012). Their website not only has the link to the PCA
Safety Checklist itself but also links to several columns and blogs
regarding PCA safety, PCA hazards, monitoring, capnography, etc. These are
excellent resources.
Another excellent resource on PCA safety is the San Diego
Patient Safety Council and the San
Diego Patient Safety Taskforce, which put together a tool
kit for PCA safety. It is a comprehensive document that discusses
assessment for PCA appropriateness, distinction between opioid naďve and opioid
tolerant patients, PCA patient education, pain assessment, sedation assessment,
respiratory assessment, monitoring, adjuvant therapies (eg. for treating side
effects of opioid therapy such as constipation, nausea and vomiting, pruritis),
multimodal pain management strategies, standardized order sets, and specific
issues related to equipment and products.
Other Patient Safety Tips of the Week pertaining to opioid-induced respiratory depression and PCA safety:
January 4, 2011 “Safer Use of PCA”
July 13, 2010 “Postoperative Opioid-Induced Respiratory Depression”
May 12, 2009 “Errors With PCA Pumps”
September 21, 2010 “Dilaudid Dangers”
November 2010 “More on Preoperative Screening for Obstructive Sleep Apnea”
February 22, 2011 “Rethinking
Alarms”
May 17, 2011 “Opioid-Induced
Respiratory Depression – Again!”
September 6, 2011 “More
Tips on PCA Safety”
December 6,
2011 “Why
You Need to Beware of Oxygen Therapy”
February 21, 2012 “Improving
PCA Safety with Capnography”
October 2012 “Another
PCA Pump Safety Checklist”
Tools:
PCA
Pump Audit Tool and the PCA
Pump Criteria
Our prior columns on obstructive sleep apnea in the perioperative period:
June 10, 2008 “Monitoring the Postoperative COPD Patient”
August 18, 2009 “Obstructive Sleep Apnea in the Perioperative Period”
August 17, 2010 “Preoperative Consultation – Time to Change”
July 13, 2010 “Postoperative
Opioid-Induced Respiratory Depression”
July 2010 “Obstructive Sleep Apnea in the General Inpatient Population”
November 2010 “More on Preoperative Screening for Obstructive Sleep Apnea”
February 22, 2011 “Rethinking
Alarms”
November 22, 2011 “Perioperative
Management of Sleep Apnea Disappointing”
March 2012 “Postoperative Complications with Obstructive Sleep Apnea”
May 22, 2012 “Update
on Preoperative Screening for Sleep Apnea”
References:
California Health
and Human Services Agency Department of
Public Health (CDPH).
State of Deficiencies and Plan of Correction. 2012
ASGE Technology Committee, Gottlieb KT, Banerjee S, Barth BA, et al. Monitoring equipment for endoscopy. Gastrointestinal Endoscopy 2013; 77(2): 175-180
http://www.giejournal.org/article/S0016-5107%2812%2902755-1/fulltext
Lynn LA, Curry JP. Patterns of unexpected in-hospital deaths: a root cause analysis. Patient Safety in Surgery 2011, 5:3 (11 February 2011)
http://www.pssjournal.com/content/pdf/1754-9493-5-3.pdf
PPAHS
(Physician-Patient Alliance for Health & Safety)
PPAHS
(Physician-Patient Alliance for Health & Safety). Physician-Patient
Alliance for Health & Safety Announces New Expert Checklist for
Facilitating Safety of Hospital-Based Intravenous Patient-Controlled
Analgesia Pumps. July 17, 2012
PPAHS. PCA Safety
Checklist.
http://ppahs.files.wordpress.com/2012/07/pca-safety-checklist3.pdf
San Diego Patient
Safety Taskforce. Tool Kit: Patient Controlled Analgesia (PCA) Guidelines of
Care for the Opioid Naďve Patient. Published: December 2008
http://www.patientsafetycouncil.org/uploads/Tool-Kit-PCA_Dec_2008.pdf
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