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Patient Safety Tip
of the Week
September
15, 2020
An Eerily Familiar Incident
In
our April 2, 2007 Patient Safety Tip of the Week “More Alarm Issues” we described a catastrophic case with
numerous lessons learned. A patient with asthma arrived mid-morning at an
emergency room with status asthmaticus. Treatment was begun but the patient
required intubation and mechanical ventilation. He was stabilized and the ICU
was called to admit the patient. The ICU had no empty beds but told the ER that
they expected a bed to open up shortly. The ER said the
patient could stay on a ventilator in an ER room until that bed was ready.
Respiratory Therapy evaluated the patient and hooked the patient up to a dual
power-source portable ventilator. That was felt to be ideal for this patient
because it could be used either with typical AC current in the ER or use its
built-in battery during transport.
Investigation
revealed that no staff had heard any alarms on the EKG monitor even though it
was likely the patient would have developed tachycardia and/or bradycardia
after the ventilator had ceased functioning. The alarm volume, in fact, had
been turned down to a level barely audible even by those in the immediate room.
The room was immediately adjacent to the nursing and secretarial work area and
staff had turned down the alarm volume because it distracted them from work.
When
the hospital team conducting the RCA investigation
came to the ER to re-enact the events, they found that the volume on the same
alarms had been turned down again. A similar visit done with the health
department a week later again found the alarm volume turned down.
Avoiding
the snap reaction to take punitive action against the staff member who had
initially turned down the alarm volume, it became very clear that the root
cause was a flawed design to the ER plus a serious problem with the “culture”
in the ER. That design of the ER led to the practice of turning down the alarm
volume. One wonders how many ER’s, ICU’s, etc. suffer from this same type of
design flaw that promotes such an unsafe practice. I’m
always amazed when a hospital administrator proudly states “we designed this
unit to have full visual contact of all patients”, only to find that the very
proximity led to this practice of lowering alarm volumes. A second root cause
was the development of a “culture” in the ER that tolerated manipulation of the
alarms as an unsafe workaround.
Another
root cause was in the design of the portable ventilator. How was one to know
that it was functioning on battery power rather than AC power from the wall
outlet? In fact, it did have an indicator light to flag which power source was
being utilized. However, that indicator light was located on the back of the
unit and not readily visible to staff in the room.
The
case is also a good example of how technological “safety” advances may not
actually reduce accidents, much like maritime radar simply encouraged ships to
go faster. In this case, the “ideal” dual power-source ventilator fostered a
false sense of security.
Lastly,
the bottleneck caused by bed unavailability in the ICU was yet another root
cause that led to implementation of a better system for triage of ICU beds.
A
very unfortunate case but it illustrates multiple points that one often sees in
cases with adverse outcomes (cascade of errors, latent errors, violations,
unsafe workarounds, communication breakdowns, misuse of alarm systems, multiple
design flaws, safety “culture” issues, bottlenecks and patient flow issues, and
technological advances with unintended consequences).
Fast forward to 2020. A recent Anesthesia
Patient Safety Foundation (APSF) case report (Levin
2020) sounds eerily similar to that incident. During
the COVID-19 crisis, a patient with respiratory failure was housed in a
windowless negative pressure room in a telemetry unit that had been converted
to a temporary COVID-19 ICU. Because of the concomitant ventilator shortage, an
anesthesia machine ventilator was used to ventilate the patient. On the tenth hospital
day an audible alarm sounded at the central station and the patient’s SpO2 was
noted to be 45%. Staff responding to the alarm found that multiple things
controlled by electricity in the room were not working. The anesthesia
ventilator itself was not working and its workstation control screen was dark.
The AC power indicator light was off. However, the physiologic monitor, which
had a separate battery backup system, was on and functioning. The patient was
removed from that ventilator and manually bagged, with prompt return to
baseline oxygen saturation levels.
Investigation confirmed that the power supply
to the anesthesia machine had been lost due to a tripped circuit breaker, just
as in our earlier case. Review of the service log revealed an AC power loss and
appropriate cutover to the backup battery. Several alarm messages had been
displayed on the workstation screen beginning 28 minutes after the AC power
loss progressing from “Battery Low”, “Battery V Low” to “Battery V VERY LOW”
and, after 1 hour 43 minutes, to “Battery Empty.” The system shut down after 1
hour 52 minutes. Thus, the anesthesia machine had functioned fully as it was
designed to work. It was also likely that use of several electrical appliances in
the room may have led to the circuit breaker tripping.
During normal use of an anesthesia
workstation, “a qualified anesthesia provider is in constant attendance, able
to view the screens, hear audible alarms, and make adjustments as necessary”.
The APSF/ASA Guidance on use of such workstations as ventilators elsewhere
includes the recommendation that “An anesthesia professional needs to be
immediately available for consultation, and to ‘round’ on these anesthesia
machines at least every hour.”
Fortunately, the patient in the Levin case
did not suffer the dire consequences seen in our earlier case. But the
similarities between the two cases are striking. In each case, the tripping of
the circuit breaker went unnoticed and staff were unaware that the ventilator
was running on battery backup power. While each device did have an indicator
that it was on battery backup power, that indicator was either in a position
not readily visible or the screen with the warning was not observed because no
one was in the room. Multiple root causes were involved in both cases. Unforeseen
circumstances led to the use of the surrogate ventilator in both cases (the
COVID-19 pandemic in the Levin case, and the ICU backup on our first case).
Staff unfamiliarity with the devices may have played a role in each case. Poor
design of the working area contributed in both.
The Levin study notes that many conventional
ventilators used in ICU’s today also have battery backup systems, some of which
only last an hour and that the same problem could have occurred with a
conventional ventilator. They also note that some of those ventilators lack the
remote monitoring capability that was critical in alerting staff in the current
case.
Our recommendations
from lessons learned in these 2 cases:
- Be aware that any time you use equipment
that is unfamiliar to staff, errors will be more likely. Extra vigilance
is required.
- Similarly, makeshift environments that
are unfamiliar to staff may also be more prone to unexpected events.
- All equipment that has a “backup”
(battery) electrical system should have a readily visible tag that states “This system has a battery backup that is expected
to last ___.” “It was last checked on _____ and battery capacity was at
___%. You need to be aware that the primary electrical source could be
interrupted without your awareness.” It should also indicate how you would
be notified if the unit switched to battery backup power.
- Battery capacity should be checked
immediately before the equipment is deployed to patient use.
- There must be a way in which the staff
become aware that the unit is on battery backup power (that must include
audible as well as visual alerts).
- The machine then must be deployed in a
manner that they will be alerted when the battery runs out.
- Do an inventory to see which of your
devices have battery backups.
- You need a system for regular battery
checks on all equipment that runs on batteries (our February 4, 2014
Patient Safety Tip of the Week “But What If the Battery Runs Low?”).
- Don’t purchase
a machine that lacks a readily visible way to alert staff the machine is
on battery power (don’t put the indicator light on the back of the
machine!!!).
- For equipment like ventilators, don’t use an outlet that is also being used by multiple
other devices.
- Whenever possible, put your monitoring
devices/alarms on an outlet separate from the one the ventilator is on.
Our bet is that these are not the only cases
out there where failure to recognize equipment is running on battery backup led
to disasters or near misses. The potential contributing factors are likely
present in many hospitals.
References:
Levin MA, Burnett G, Villar
J, et al. Anesthesia Machine as an ICU Ventilator-A Near Miss. APSF (Anesthesia
Patient Safety Foundation) 2020; September 4, 2020
https://www.apsf.org/article/anesthesia-machine-as-an-icu-ventilator-a-near-miss/
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