Isolated Limb Perfusion – A Case Report
Introduction
Isolated limb perfusion
is an uncommon practice sometimes employed with patients
who suffer from localized malignant tumors. Most
malignancies are found systemically and not peripherally,
so the chemotherapeutic agent is systemically
administered at lower concentrations to combat the
malignant area. However, the malignancies that limb
perfusion may be most beneficially used are found in the
legs or the arms. Isolated limb perfusion enables the
perfusionist to infuse higher concentrations of the
chemotherapeutic agents into the isolated limb without
introducing these agents systemically. The perfusion of
the chemo agent , blood flow and oxygenation of the blood
is performed using a standard hear/lung machine.
The patient was a 76
year old white male who was presented to the operating
room suffering from osteogenic sarcoma of the left leg
and Paget’s disease. The patient was 173 cm tall and
80 kg in weight. The B.S.A. was calculated at 1.95 m2
and the calculated flow was 4.3 LPM at a flow index of
2.2 LPM/m2. The calculated left leg flow was
to be .770 LPM (18% of total B.S.A.). The patient’s
pre-bypass hematocrit was 39% and no known drug allergies
were documented.
Methods and
Materials
In this case, the
patient suffered from osteogenic sarcoma of the left leg.
The membrane oxygenator that was used was the Cobe Duo
with a pediatric tubing pack. The chemotherapeutic agent
that was used was Cisplatin at 2mg/kg or approximately
160 mg. A radioactive isotope tracer agent called I-125
was used through nuclear imaging to track the chemo
agent’s concentration systemically. Therefore, if
traces of the I-125 isotope were to be found systemically
in increasing quantities, this would indicate a leakage
of the Cisplatin into the system. The prime consisted of
1000 ml of Lactated Ringers and 5000 U of heparin. A
Kirchner rod was to be inserted into the hip which
provided a pivotal point for the isolation of the leg.
The cannulae were to be inserted via the femoral artery
and vein. The arterial cannulae was an 18F JB type 1855
with a 1/4″ x 1/4″ connection and leuer. The
venous cannulae was a 24F Bard WW with a 3/8″ x
3/8″. Elastic rubber band straps were used as the
tourniquet for the isolation and are placed tightly and
securely around the Kirchner rod and around the leg. The
FIO2 was placed on 50% with a sweep ratio of
1:1. A heat lamp was placed over the malignant area of
the leg and heated to a hyperthermic condition of
approximately 40oC. Four sites were to be
measured on the leg to monitor the temperature;
mid-thigh, lower thigh, mid-calf and lower calf.
Temperature probes were placed in each of these four
locations to correctly monitor these temperatures. The
pre-bypass blood gases, ACT, temperatures, pressures and
osmolarity were all measured at this time.
After the cannulae were
inserted and the tourniquet was fastened, the drug was to
be infused slowly over 5 minutes at approximately 400
ug/m2. The I-125 Albumin or radio-iodine
labeled human serum albumin (RIHSA) was given by the
surgeon at the field via the arterial cannulae. This was
used to measure any systemic chemo agent leakage as
mentioned before. Hyperthermic conditions were instituted
and blood flows, oxygenation, blood gases and temperature
were continuously monitored.
At approximately one
hour post infusion, the rinsing of the isolated limb was
begun. The purpose of this portion of the procedure was
to completely wash out the chemo agent (Cisplatin) of the
leg and replace it with packed red blood cells. First of
all, the venous line was clamped on the membrane side of
the stopcock. The venous blood returning from the leg was
diverted into a hazardous waste container and discarded
appropriately. The chemo rich perfusate was chased with
two liters of Lactated Ringer’s solution and then
two bottles of a Dextran-containing solution. When the
venous line appeared clear, it was assumed that the
Cisplatin had been completely cleansed from the leg. At
this point, two units of red blood cells were perfused
into the leg until the blood was seen through venous
line, which was now diverted back into the venous
reservoir. Finally, the remainder of the blood that was
left in the reservoir was perfused into the leg with
venous line clamped and then chased with approximately
one liter of Lactated Ringer’s. Upon completion of
this stage, all stopcocks were closed and limb bypass was
terminated.
Results and
Discussion
As mentioned earlier in
the paper, special attention was given to the measured
values of the patient and the left leg separately. The
patient and the left leg were considered as two separate
entities. The blood gases, osmolarity, and the activated
clotting times (ACT) of the patient and the leg were
recorded separately. Special care was given to the
osmolarity within the leg to keep it within normal
limits. Using the following formula, we were able to
compute the amount of water that needed to be added to
the leg in order to decrease the osmolarity of the leg.
- [Baseline
osmolarity on pump of leg] / [Total volume (limb
+ prime)] = Desired Osmolarity / X
- Total volume – X =
ml of H20 to be added
- Amount of water in
ml to be added is then divided by two
In this case, baseline
osmolarity was 280 mOsm/L and total volume was two
liters. The desired osmolarity is the body’s normal
osmolarity unless otherwise indicated. After calculation
of the water to be added, we concluded that no addition
of water was needed to reduce the osmolarity of the leg
in this particular case. Furthermore, the ACTs of the leg
were continuously recorded at over 600 seconds, while the
patient’s ACTs measured between 300-400 seconds. The
maximum temperature reached at either of the four before
mentioned locations on the leg was approximately 40oC.
The total chemo agent perfusion time was 60 minutes and
the total perfusion time was 85 minutes. Bypass was
terminated with no problems.
Osteogenic sarcoma is a
malignancy of the connective tissue of the bone. These
tumors usually develop rapidly and metastasize through
the lymph channels and can be fatal is left untreated.
Paget’s disease, which compounded this
patient’s problems, is described as lesions of the
bone. The disease disturbs the growth of new bone tissue
and the bones often thicken, becoming soft and coarse in
texture. In advanced states, the weakened bone may
fracture or collapse. In this case, isolated limb
perfusion was used because of the location and the
severity of the malignant tumor. Isolation limb perfusion
is not a common practice of many hospital oncology
departments, but it is an effective and less detrimental
alternative to systemic chemotherapy.
