Basic Monitors and Monitor Lines
A. Which way will the OR table turn? Being able to
predict which way the OR table will turn is
important pre-knowledge. The simplest rule for
lesions not in the midline of the brain is that
the arm opposit the lesion will come toward the
anesthesia machine. Plan on placing the A-Line,
antecubital CVP line and perhaps the peripheral
large bore IV in this arm. If the patient is in
lateral position, the other arm may be easily
utilized.
1. Arrange monitor lines so that tangling can
be avoided when the bed turns. The
transducers can be attached to the "post
and plate" which slides under the mattress
on the OR table. The transducers should be
attached to the table prior to the patient
coming into the room. The arrangement
makes it unnecessary to adjust transducer
height when the table is raised or
lowered. However, when the table is tilted
side to side or put in Trendeleburg, the
CVP will change. If the change is a result
of rotation from side to side, adjust the
transducer height so that CVP measurement
stays constant. If it is the result of
Trendelenburg, a new normal value is
established.
2. For patients operated on in the lateral
position, the A-line is placed in the down
arm.
3. The basilar artery at the base of the
brain is essentially in the midline which
makes invalid the above rule for
predicting table turns. The approach is
usually from a right sided incision unless
the aneurysm points to the right side. The
surgeon will most probably want the table
turned so that the aneurysm is pointing
away from him. The operation is then done
in the supine position with a shoulder
roll and the head turned toward the
anesthesia machine.
4. Aneurysms of the anterior communicating
artery are ususally approached from a
right pterional incision. Exceptions to
this rule do exist, however.
5. Vertebral artery aneurysm surgery is
usually done in a lateral oblique
position.
6. For prone cases that are induced and
intubated on the Gurney, place as many
lines as possible in the arm that will be
closest to the OR table. For example, if
the gurney is to the patient's right of
the OR table, place lines in the left arm.
B. Arterial Lines
1. Placed prior to induction for aneuryms.
2. Tape stopcocks that will become
inaccesible after draping the patient in
order to prevent their inadvertent
opening.
3. The A-line transducer is placed at ear
level for sitting cases. (10" = 20mmHg or
1.3cm H2O = 1mmHg)
C. Antecubital Long Lines
D. Triple lumen catheters in the subclavian or
internal jugular are often placed by the
surgeon prior to surgery as well as in the OR.
Ideally, these are placed on the side opposite
the intracranial lesion. If the CVP line is
placed on the opposit side, several
intraoperative problems can occur. When the
drapes go on, it may become very difficult to
gain access to the catheter. Placement of
extensions on the catheters may be necessary.
The catheters may become kinked off when
brought across the body. Secure them in such a
way that the possibility of kinking is minimized.
Kinking is possibile even when the catheter is
placed on the side of the body closest to the
anesthesia machine (especially with IJ lines).
E. Precordial Doppler
Fiberoptic Intubation