18
2.17
ALARM
CONDITIONS
There
are
a
number
of
conditions
for
which
the
PTS
ii
will
produce
visual
and
audible
alarms.
Those
conditions,
indications
and
appropriate
actions
are
shown
in
Table
2.1.
The
appropriate
actions
indicated
are
based
on
the
most
probable
causes
and
should
only
be
used
as
a
guide.
Other
causes
of
alarm
conditions
may
indicate
a
need
for
other
actions.
The
alarm
indicator
light
is
illuminated
and
an
audible
alarm
tone
is
produced
whenever
a
alarm
condition
is
detected.
2.20.1
ALARM
SILENCE
FUNCTION
Most
audible
alarm
tones
may
be
silenced
for
30
seconds
by
momentarily
depressing
the
alarm
silence
button
which
is
displayed
whenever
a
silencable
alarm
condition
is
present.
At
the
end
of
the
silenced
period,
the
alarm
tone
will
restart
if
the
alarm
condition
has
not
been
corrected.
The
alarm
tone
may
be
silenced
for
additional
30
second
periods
as
required.
2.20.2
PRESSURE
HIGH
or
LOW
ALARMS
A
"HIGH
PRESSURE"
or
"LOW
PRESSURE”
alarm
will
occur
when
the
pressure
in
a
cuff
is
more
than
15
mmHg
from
the
pressure
set
point.
To
minimize
nuisance
alarms
that
can
be
caused
by
vigorous
movement
of
the
patient's
limbs,
a
1
second
delay
has
been
designed
into
alarm
actuation
for
these
conditions.
2.20.3.
LEAK
ALARMS
It
is
possible
for
the
system
to
have
a
substantial
leak
that
the
unit
can
compensate
for
by
continual
pumping.
This
type
of
leak
could
be
due
to
a
hole
in
the
cuff
or
hose
assembly,
a
loose
or
worn
hose
connector,
or
leaks
in
the
pneumatic
circuit
inside
the
PTS
ii
unit.
All
leaks
require
immediate
attention,
because
they
could
progress
into
a
total
failure
of
a
cuff
to
hold
pressure
at
any
time.
To
alert
the
operator
that
a
substantial
leak
is
present,
the
“CUFF
LEAK”
alarm
is
activated
when
this
type
of
leak
is
continuously
present
for
more
than
7
seconds,
even
if
the
unit
is
maintaining
the
cuff
pressure
within
15
mmHg
of
the
set
point.
If
a
“CUFF
LEAK”
alarm
occurs,
the
cuff,
hose
assembly,
and
hose
connectors
should
be
checked
for
leaks.
If
an
external
leak
cannot
be
found,
test
the
PTS
ii
unit
per
Section
3.4
below.2.8.2.
2.20.4
INTERNAL
HARDWARE
FAILURES
When
“SYSTEM
ERROR”
and
a
numeric
error
code
appear
in
the
pressure
and
time
displays
during
use
or
power
‐
up,
an
internal
hardware
failure
has
likely
occurred
and
the
PTS
ii
unit
is
unusable.
In
this
situation,
it
is
likely
that
the
unit
has
put
itself
in
the
‘safe
state’
mode,
in
which
the
pneumatic
valve
and
pump
are
disabled
and
the
current
pressure
in
the
cuff
is
held
(in
the
absence
of
leaks).
It
is
also
likely
that
a
tone
will
sound
under
these
conditions.
The
‘safe
state’
mode
helps
prevent
unexpected
loss
of
occlusion
during
a
procedure
if
a
sudden
failure
occurs.
Although
it
is
very
unlikely,
internal
hardware
failures
may
also
cause
erratic
operation
and/or
unintelligible
displays
with
or
without
alarms,
and
may
or
may
not
put
the
PTS
ii
in
the
‘safe
state’
mode.
If
either
type
of
error
occurs:
a)
Set
the
unit
to
standby
by
pressing
the
‘ON/STANDBY’
button.
This
removes
power
from
the
internal
instrument
circuitry
and
all
instrument
functions,
causing
the
cuff
to
hold
pressure
(in
the
absence
of
leaks).
b)
If
required,
attempt
to
restart
the
unit
by
pressing
the
‘ON/STANDBY’
again
to
restart
the
unit.
c)
If
required
to
continue
the
procedure,
clamp
the
hose
with
a
hemostat
to
maintain
cuff
pressure,
then
immediately
disconnect
the
faulty
PTS
ii
unit
and
connect
a
replacement
unit.
d)
If
cuff
deflation
is
required,
disconnect
the
cuff
from
the
PTS
ii
unit.
WARNING
:
In
all
cases
of
internal
hardware
failure,
erratic
operation,
or
unintelligible
displays,
it
is
possible
that
the
pressure
in
the
cuff
is
not
accurately
displayed
on
the
PTS
ii
unit
and
that
cuff
pressure
may
be
present
even
when
the
PTS
ii
unit
appears
to
be
shut
down.
The
user
must
immediately
determine
if
the
cuff
is
inflated
or
deflated
and
continually
monitor
the
cuff
to
ensure
patient
safety.
If
deflation
of
the
cuff
is
necessary,
disconnect
the
hose
from
the
PTS
ii
unit
or
from
the
cuff
and
confirm
that
the
cuff
deflates
completely.
