Treating with the Circulator Boot: Long Boot, Mini-Boot or Both?
Long-Boot: The patient sits
erect on a treatment table with leg extended horizontally. The
Long-Boot encompasses the whole lower limb from the toes to the groin.
The leg is first inserted into a double-walled plastic bag to contain
the compressed air. Velcro straps are provided to contour the bag
closely to the upper thigh and as close to the groin as possible. A
Velcro foot sock is also provided to protect the heel from rubbing and
to hold the plastic bag close to the foot thus preventing it from
tenting up and away from the foot with the repeated introduction of
compressed air. The bagged leg is then inserted into the rigid
Long-Boot and the dead space
around the leg is minimized by moving the adjustable inner walls of the
boot closely against the leg and by folding the thick plastic aprons on
the walls snuggly against the top of the leg. Inflation of the plastic
bag at this point provides an equal pressure from the groin to the
toes. The system is designed to pressurize the boot to 30 inches water
pressure (56.2 mm HG or 1.09 PSI) within 0.38 to 0.44 seconds. As
momentum (mass times velocity) is equal to the product of force and
time, these settings are more than adequate to move the lymphatic and
venous columns (perhaps with a vertical height of 18 inches) out of the leg toward the heart.
Mini-Boot: The patient sits
in a chair with feet on the floor during Mini-Boot treatments. Again,
the foot is first introduced into a plastic bag which commonly extends
to the knee (although any level can be chosen from the ankle to the
knee). A Velcro legging, which has a line of plastic beads providing an
open air channel, is firmly applied over the plastic bag and the bagged
foot is inserted into the rigid Mini-Boot that encloses the foot and
ankle. Here the system is designed to pressurize the bag to 45 inches
water pressure (84.9 mmHg or 1.43 PSI) within 0.34 seconds. Again the
settings are adequate to move the venous column (now perhaps with a vertical
height of 38 inches) toward the heart. The shorter compression time
allows a split second more time for the arterial inflow to reach the
lower leg. As patients with peripheral arterial occlusive disease may
have delayed inflow, leg compressions are commonly delivered after
every other beat.
Children commonly have systolic blood pressures of 80
to 95 and diastolic pressures of 50 to 60. High pressures are not
needed to adequately meet the needs of the tissues. To these brachial
pressures are added the height of the fluid column to the lower
extremity to constitute the arterial perfusion pressure at each level
of the leg. At rest the matching venous column is pushed out of the leg
by the heart; with exercise the calf pumps and with booting the boot
provides the force to return the venous column. As long as the boots do
not pump during systole or with a force adequate to push the arterial
column backwards out of the leg, the arterial-venous gradient is
maximized.
The physical laws of hydrodynamics apply to the
circulation in the leg: the diameter, length and rigidity of the
vessels along with the smoothness of their wall make a difference as
does the viscosity of the blood. The smaller tibial vessels have
a higher surface to volume ratio then the larger thigh vessels and
especially if their surface is roughened and viscosity is
increased as sludge forms, they require a higher perfusion pressure to
maintain flow. The increased pressures used in the Mini-Boot are
helpful in this regard (pressures still not sufficiently high to expel
the arterial volumes). The vasculature, however, differs from the rigid
tubes studied in the physics laboratory. Healthy arteries are
muscular tubes that like a balloon expand as the heart pushes its
stroke volume into the aorta and raises the pressure to systolic
levels. The recoil of the muscular wall as volume is lost to runoff,
prevents the diastolic pressure from falling to very low levels as
happens in the rigid tube. The avoidance of boot pressure during
systole helps promote the expansion of the arteries during systole and
their acceptance of blood volumes. The application of pressure during
diastole provides pressure to disseminate these volumes throughout the
area under the boot bag. The quick pressure pulses of the boot produce
arterial waveforms much like those seen in normal tissue.
Again, the vasculature differs from the rigid tube in
the physics laboratory: the internal lining of the artery, the
endothelium, is capable of elaborating hormones, fibrinolysins and
reactive vascular substances. The sheer forces generated by the
pulsations of the boot promote the endothelial elaboration of nitric
oxide and prostacyclin (vasodilators) along with fibrinolysins
(substances capable of dissolving unwanted clot) and vascular
endothelial growth factors (promoters of the development of new vessel
formation).
The timing of the release in boot
pressure is also important. The Circulator Boot Heart Monitor signals
release of boot pressure 0.04 seconds before the next expected QRS
complex (electrical systole which precedes mechanical systole) allowing
time for the falloff in leg pressure to reach the aortic valves of the
heart...thus, maximizing afterload reduction and significantly
increasing cardiac output and stroke volume. This effect is
significantly greater with Long-Boot therapy which is compressing the
large arteries in the upper thigh. If cardiac support is needed,
Long-Boot therapy is indicated.
Indications for Long-Boot:
- Need for cardiac support
- Venous stasis disease
- Lymphedema Diffuse arteriosclerotic disease significantly involving the arteries above and including the popliteal
Indications for Mini-Boot:
