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Frequently
Asked Questions About Manual Tourniquet Model |
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How
do I determine optimal pressure for Tourniquet
operation? |
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Setting
tourniquet pressure as a function of a patients
pre operative systolic Blood Pressure is inadequate
because it does not take into account adjustments
that must be made due to differing cuff widths,
differing degrees of matching between cuff
shape and limb shape,differing degrees of snugness
of cuff application to the limb and differences
in the characteristics of the limb tissue beneath
the cuff. Therefore setting tourniquet pressure
as a function of LOP inherently takes into
account all of these variables.
Hence the optimal guideline for setting the pressure
of a constant Pressure Tourniquet is based on "Limb
Occlusion Pressure" (LOP). For increased safety,
pressure be set at "Minimum Effective Pressure"
as there is no "Maximum Safe Pressure".
LOP can be defined as the minimum pressure required,
at a specific time in a specific tourniquet cuff
applied to a specific patients limb at specific
location, to stop the flow of arterial blood into
the limb distal to the cuff. |
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Currently
established guideline for setting tourniquet
pressure based on LOP is an under: |
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*
For single Bladder tourniquet cuffs of any
width and type that are applied to the
upper limb of an adult, tourniquet pressure should
be set at LOP + 50 mmHg .
* For single Bladder tourniquet cuffs of any
width and type that are applied to the
lower limb of an adult, tourniquet pressure should
be set, at LOP + 75 mmHg .
* For Dual Bladder (Bier Block) tourniquet cuffs
of any width and type applied to
an adult, LOP should be measured for each bladder
and tourniquet pressure
should be set at the
higher LOP + 100mm Hg.
* pediatric guidelines based on LOP are currently
being investigated.
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LOP
can be measured in two basic ways, for a specific
cuff applied to a specific limb at
specific limb location. First, cuff pressure
can be increased slowly from Zero while
monitoring the pulse in an artery distal to the
cuff until the distal pulse disappears;
the lowest cuff pressure at which the pulse
disappears can be defined as the ascending LOP
Second, cuff pressure can be decreased slowly
(1mmHg/sec.) from a high occlusive
level while monitoring an artery distal
to the cuff until a distal pulse resumes; the
highest pressure at which pulsatile flow first
resumes can be defined as the descending
LOP. The mean of the ascending and descending
LOP can be used as an estimate of the
true LOP. |
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*Over-pressurization
of cuff is associated with a higher probability
of nerve injury and other soft tissue injuries,
and under-pressurization is associated with the
leakage of arterial blood distally'and anesthetic
agent proximally in Bier block procedure. |
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When
I set desired pressure I find it is less after
5 to 10 minutes. Is it normal if I find reduction
in set pressure after some time say 5 to 10 minutes
? |
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Yes
. The reduction in pressure of the Tourniquet
is very normal because of the adjustments in
pressure due to differing degrees of matching
between cuff shape and limb shape.
We suggest:
1) Keep
initial pressure higher by about 50 mmHg to compensate.
OR
2) Further inflate to desired
pressure level after settling down in initial
5 to 10 minutes. |
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During
the operation will pressure remain stable to
the set pressure ? |
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Not
really. This is due to the body movement, body
position chaning during the
operation. The pressure may increase if the cuff
gets pressed or may decrease A) If cuff
displaces to lesser circumference part of the
body. B) due to small leakage in the system
at joints etc.
We suggest:
Keep observing pressure reading periodically
and adjust as required. |
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What
is the advantage of mmHg scale over some non-standard
scale ? |
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The
mmHg scale relates directly to the patient's
systolic blood pressure (which is
measured in standard pressure measuring unit:
mmHg.) and gives much better
resolution for cuff pressure reading during
surgery and also while setting tourniquet
pressure as a function of LOP during estimation
of true LOP. |
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Even
after setting tourniquet cuff pressure properly,
some times oozing of blood is noticed what could
be the reason ? |
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A)
It may happen systolic pressure increases during
the operation for any reason.
B ) If cuff pressure
is not set using the guideline for setting tourniquet
pressure based on LOP.
C ) Pressure might have reduced due to some leakage
in system and not monitored / corrected periodically. |
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Is
the Electronic Tourniquet similar to manual Tourniquet
? |
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As
far as application is concerned, yes . However
the Electronic Tourniquet with Automatic pressure
control is far superior to manual tourniquet
as pressure is always maintained to the set value
and hence the set value can be lowered to "Minimum
Effective Pressure" safely and pressure
variations are taken care automatically plus
with built in timer many more facilities
are provided. |
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| How will I know
the status about my Tourniquet system ? |
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| Test Procedure for Manual Tourniquet |
| Testing Procedure is as under |
1) Wrap the cuff under
test on a hard glass bottle in a skin tight
fashion or on a small size oxygen cylinder.
( Normally we take Modified leg size cuff )
2) Connect the coiled tube
end of this cuff to the Blue ring PUC connector
coming out from Main Tourniquet unit.
3) Pressurize the cuff with
the help of Rubber bulb assembly or the given
foot pump assembly.
4) Stop pressurizing when
the pressure on the Dial gauge passes 450
mm of Hg.
5) Allow the cuff pressure to reduce gradually
by pressing the fine control knob given on
the main unit.
6) Set the cuff pressure at around 450 mm
Hg.
Allowable Cuff Pressure setting for different
types of cuffs is as under
a) Modified Leg cuff .... 450 mm Hg
b) Standard Arm cuff .... 300 mm Hg
c) Child Cuff .... 200 mm Hg
7) Now , allow 3 to 4 minutes
to get the cuff pressure stabilize ( The
size and shape of wrapped cuff gets adjusted
to the circumference of the glass bottle
)
8) Now, after pressure gets stabilized, read
the pressure value on the gauge.
9) Start counting minutes in your wristwatch.
Read the pressure value on the gauge after
every 5 minutes or 10 minutes
The pressure drop in the system should be
less than 35 to 4o mm of Hg
maximum in one hours time in steady state
condition.
If you can carry out this procedure at your
end and you find the pressure drop more than
the above said value, then you will please
return the main Tourniquet unit along with
available cuffs to us and we will take further
action in the matter. |
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