Chapter 131

2150 PART 6 ■ Specific Considerations
risk of failure and harm in processes and to identify the most
important areas for process improvements. Teams use FMEA to
evaluate processes for possible failures and to prevent them by
correcting the processes proactively rather than reacting to adverse
events after failures have occurred. This emphasis on prevention
may reduce risk of harm to both patients and staff. FMEA is
particularly useful in evaluating a new process before implementation
and in assessing the impact of a proposed change to an
existing process. FMEA includes review of the following:
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Steps in the process
Failure modes (What could go wrong?)
Failure causes (Why would the failure happen?)
Failure effects (What would be the consequences of each
failure?)
FMEA identifies the opportunities for failure, or “failure
modes,” in each step of the process. Each failure mode gets a
numeric score that quantifies (1) likelihood that the failure will
occur, (2) likelihood that the failure will be detected, and (3) the
amount of harm or damage the failure mode may cause to a person
or to equipment. The product of these three scores is the risk
priority number (RPN) for that failure mode. The sum of the RPNs
for the failure modes is the overall RPN for the process. As an
organization works to improve a process, it can anticipate and
compare the effects of proposed changes by calculating hypothetical
RPNs of different scenarios. The FMEA can be used in two
separate but related ways. Teams can use FMEA to discuss and
analyze the steps of a process, consider changes, and calculate the
RPN of changes under consideration. They can use FMEA to
“verbally simulate” a change and evaluate its expected impact in a
safe environment, before testing it in a patient care area. Some
ideas that seem like great improvements can turn out to be changes
that would actually increase the estimated RPN of the process. In
addition to using FMEA to help evaluate the impact of changes
under consideration, teams can calculate the total RPN for a
process and then track the RPN over time to see whether changes
being made to the process are leading to improvement. Numerous
online resources are available to assist teams with FMEA. 44
CASE DISCUSSION
Everyone can remember the horror of presenting at old style
QA/QI rounds, where ABC meant “Accuse, Blame, and Criticize”—
and you were the one who would be blamed. If we are to learn from
our near misses, we must conduct our analysis in a way that it is
nonpunitive and where voluntary, anonymous reporting is not only
possible, but is encouraged. NASA and the airline industry have
had such anonymous, voluntary systems in place for some time. 45
Recently, a framework for analyzing the root causes of adverse
events and for looking at the barriers that are available to prevent
the error from reaching the patient was described by one of the
authors. 6 This framework has been helpful in our departmental
QA/QI discus sions to steer the discussion away from individual
blame. We be lieve that voluntary reporting is more likely to occur
in a situation where we always look for something to fix, not
someone to blame.
The following case was described by an anesthesiolgy trainee.
“I was asked to help out with a hepatocarcinoma resection. I came in
around 7:15 pm and the Attending anesthesiologist and I decided to
switch to isoflurane for maintenance, as the case was likely to be
prolonged. Desflurane and sevoflurane vaporizers were in position on
the machine, with the sevoflurane vaporizer in use. I replaced the
desflurane vaporizer with an isoflurane vaporizer: I locked it and
turned on the agent.
Ten to 15 minutes later, there was an episode of hypotension that
required resuscitation with blood products and vasopressors. I turned
down the vaporizer setting to an Fi isoflurane 0.4% to maintain some
anesthesia. There was ongoing massive transfusion of blood products
throughout this time. The end tidal agent analyzer read 0.7% and
then 0.5% over next thirty minutes.
I was then asked to leave the room and do another case and came
back an hour later to help out. It was noted that the end tidal agent
analyzer was not registering any agent, although the vaporizer was
still switched on at about 0.4%. The Attending and resident had
taken off the circuit briefly to see if they could smell agent and both
had thought that they could and so attributed the reading of zero
end-tidal agent to an analyzer error. Finally at around 20:45 pm it
was noted that the isoflurane canister was not seated properly on the
machine (despite the locking mechanism in the “locked” position)
and so the end-tidal agent reading of zero was real. We reseated the
canister, gave the patient 4 mg of midazolam for its amnestic effects,
informed the surgeons, and continued with ongoing resuscitation
with low level end-tidal agent for amnesia. The case ended at around
3:00 am. He has not yet reported anything suggestive of awareness,
but we are continuing to visit him to ask about this possibility.
How do you prevent this from happening in the future? More
vigilance of course, but that’s easier said than done. Perhaps a
different locking mechanism design on the vaporizer? Is it possible to
have an alarm system on the vaporizer if it is improperly seated?
Mostly it was my fault and not a device error. I take full
responsibility.”
Here is the response from one of the authors (SR) in her role as
QA/QI director for our department.
“Errors are rarely the fault of an individual and much more often
due to a combination of factors. Here is a template that I often use
for analyzing errors.” 6
Catalyst event—your patient developed hepatocarcinoma and
needed surgery, thereby putting him in harm’s way.
System faults—we have machines that can’t accommodate
3 vaporizers, so you have to swap them out as needed. Our
vaporizers do not alarm or refuse to switch on if they are not fully
locked. The OR was busy and you were shuttled between cases,
unable to give your full attention to a difficult case.
Loss of situational awareness—the OR team noted the zero end-tidal
agent, but dismissed it as an analyzer error because they were task
overloaded due to the ongoing resuscitation. I notice the times on
the incident were well into the evening, so there were some
fatigued members of the OR team, this also contributes to loss of
situational awareness.
Human Error—the vaporizer was not locked in position correctly, no
one noticed and acted upon the reading of zero end-tidal agent.
Barriers for safety that can potentially trap and mitigate an error
are:-
Technology—technology did help you in that there was a reading of
zero end-tidal agent but there were technology failures in that the
improperly seated vaporizer was not flagged as a problem by our
existing technology. At the time of the incident, the analyzer was
set to sevoflurane, not to automatic and so it was not “looking” for