Parks 915-BL, Руководство по эксплуатации и обслуживанию

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MODEL 811-B
H
OWARD
C. B
ARON
, M.D., F.A.C.S.*
Leg distress
⎯
cramps, fatigue, or just vague
pain
⎯
often signal the presence of a peripheral
vascular disease. It could be arterial
⎯
the
first sign of arteriosclerosis obliterans. Simple
office evaluation, including the patient’s
description of leg pain, and an examination of
the affected limbs, will often give a clear picture
of the underlying vascular problem
⎯
where
it is, how extensive it is, which vessels are
involved, and how adequate is the collateral
circulation.
A typical patient with arteriosclerosis
obliterans, the most common of the arterial
occlusive diseases, develops pain in one or
both legs that requires him to stop and rest
after walking a short distance. He may call it
a cramp, a charley horse, or it may be just a
feeling of tiredness in the limb after walking a
certain distance. An elderly patient often
admits to having calf pain for months or
sometimes years with “no reason to mention
it since aches and pains are bound to occur as
you grow older.” However, where he
previously could walk 4-5 blocks before the
calf pain occurred and made him stop, he’s
concerned because the pain now occurs after
walking only a block or so.
Arterial occlusive disease due to
arteriosclerosis obliterans, is insidious in onset
and often present in a patient for many years
before any ischernic symptoms occur. Rarely
will anyone complain of intermittent
claudication, the most commonest symptom
of arterial occlusive disease, while indoors.
However, walking outdoors causes the pain
to occur. There is a typical pattern to this
symptom of limb ischemia: exercise
⎯
pain
⎯
rest
⎯
relief.
Patients characterize the pain of intermittent
claudication in various ways. One will
describe it as a sensation of cramping or
tightness, “as if the leg is in a vise”. Another
will describe increasing fatigue, eventually
forcing the patient to stop walking and rest.
However, in all of these patients, resting for a
few minutes is sufficient to relieve the pain.
If the need to sit down or elevate the extremity
is a feature of a patient’s complaint, or if it
takes more than a few minutes for the pain to
abate, suspect a disease process other than
arterial insufficiency as the cause of the pain.
As the disease progresses, a different type
of pain occurs in the toes or heel. Termed rest
pain or night pain, it is an ominous symptom
of advanced arterial occlusive disease due to
multisegmental blocks in the major limb
a r t e r i e s a n d a n i n a d e q u a t e c o l l a t e r a l
circulation around these blocks. This pain
characteristically occurs in the distal portion
of the foot, the toes, over the dorsum of the
foot, in the heel area, or in the region of the
metatarsophalangeal joint. The patient
describes the pain as a severe ache or throbbing
which often wakes him after several hours of
sleep. Relief is sometimes obtained by rubbing
the affected foot or placing it in a dependent
position over the edge of the bed. Elevating
the limb often increases the pain. In some
patients, relief is afforded by sleeping in a
chair with the leg in a dependent position.
Leg pain and even “pseudoclaudication,” a
form of leg pain that can mimic true
intermittent claudication, can occur with a
variety of processes other than arteriosclerosis
obliterans such as degenerative disorders,
for example, osteoarthritis of the hip or
spondylolysis. Compression of the cauda
equina also can produce claudication-like
symptoms. In these patients, the typical cycle
of exercise-pain-rest-relief is not present.
The presence of normal pulses in the leg
and a normal ankle systolic blood pressure
a i d s in distinguishing the pain of
pseudoclaudication from arteriosclerosis
obliterans.
Examination of the affected foot yields a
great deal of information. Skin color, texture,
and consistency all depend on arterial blood
flow and can indicate the presence of an
impaired circulation.
If the patient has only mild, generally
asymptornatic occlusive arterial disease, the
color and nutrition of the leg and foot appears
normal. As the ischemic process becomes
more severe, the skin appears shiny and
smooth, and hair is often absent from the toes
and the dorsal region of the foot. Muscle
atrophy, loss of subcuataneous fat, and pallor
all indicate a severe degree of ischernia.
A fairly simple and accurate clinical test that
can measure the degree of arterial insufficiency
in the affected leg is the elevation-dependency
maneuver performed while the patient is on
the examining table. With the patient lying on
his back, place his heels in the palms of your
hands and elevate both legs 24-36 inches off
the table. Hold the legs in this position for at
least 45-60 seconds. Observe the color of the
feet and legs, particularly the soles of the feet.
If the arterial circulation is normal the skin
coloration will decrease only slightly. Skin pallor
will develop in the affected limb according to
the degree of arterial insufficiency. If pallor
occurs in both feet, suspect either an
arteriosclerotic block in the abdominal portion
of the aorta or similar blocks in the major limb
arteries. After the period of leg elevation,
generally no more than several minutes, have
the patient immediately stand up. In a patient
with normal arterial circulation in the legs, color
will return to the foot in 10 seconds or less,
and the superficial veins in the distal portion
of the foot will fill in 10-15 seconds. If arterial
insufficiency is marked, the normal color may
take 40-60 seconds to return; in severe cases
more than 2 minutes. Reactionary rubor of the
foot (a burgundy red color) may occur after the
limb becomes dependent; this indicates the
presence of advanced limb ischemia and often
portends ulceration and “ gangrene of the foot.”
An absent or greatly diminished pulse is a
diagnostic finding of major importance. The
presence of a pulse, however, does not always
indicate a normal arterial flow; its absence is
far more significant.
In a patient who complains of intermittent
claudication and has palpable resting pulses,
don’t discard the diagnosis of arteriosclerosis
obliterans without investigating the
“disappearing pulse” phenomenon. Have the
patient exercise until he experiences
claudication; examination of the ankle pulses
may then reveal an absent pulse associated
with leg pallor. The physiologic explanation
is simple: exercise causes a marked dilation of
the arteriolar beds within the exercising
muscles. During exercise blood is shunted to
these muscle groups causing a drop in the ankle
systolic blood pressure which is distal to the
site of the arterial block. As the ankle systolic
blood pressure falls, the distal pulses
disappear.
Except when life expectancy or surgical risk
contravenes due to other systemic diseases,
angiography and surgical revascularization is
indicated for all patients with symptomatic
arteriosclerosis obliterans exhibiting cutaneous
skin changes, such as ischernic ulcers or
gangrene; the presence of rest pain or
intermittent claudication that handicaps the
patient economically or socially.
Angiography is necessary to evaluate the
extent of the arterial lesion. Typical arterial
lesions due to arteriosclerosis obliterans are
segmental, occurring in areas of branching,
narrowing, or bifurcation sites of an artery.
The commonest occurring at the bifurcation
of the aorta, or the iliac and femoral artery
divisions. Another frequent site is the distal
superficial femoral artery as it emerges from
the adductor canal of Hunter and the distal
popliteal artery as it branches into the anterior
and posterior tibial and peroneal arteries.
Certain patients are not candidates for
angiography; these include the elderly patient
with moderate disability and associated cardiac
disease, and generally any patient with the
presence of another life-threatening disease. A
satisfactory angiographic study provides a
visual study of the anatomic lesion, indicating
the extent of the lesion and to a degree its
severity.
Diagnosis and Treatment of Chronic Arterial
Insufficiency of the Lower Extremities
Howard C. Baron, M.D. F.A.C.S.
*