pages S35-S41

Patient Assessment and Examples of a Method of Treatment

Use of the Circulator Boot in Peripheral Vascular Disease

Richard S.Dillon, M.D.

Bryn Mawr, Pennsylvania


Abstract: Effective peripheral blood flow is positively related to cardiac output and gravity (part dependent) and inversely related to gravity (part elevated), venous pressure, interstitial fluid pressure, degree of peripheral neuropathy, arteriosclerotic and thrombotic arterial obstructions and infection. These factors are considered in the operation of the end-diastolic pneumatic boot in the treatment of illustrative patients with lymphedema, venous stasis disease, peripheral arteriosclerosis obliterans, peripheral neuropathy, cellulitis and osteomyelitis and the failing heart. A method of treatment that includes the use of the boot and the injection of local antibiotics is described. Angiology Suppl Vol 48, Number 5, Part 2, May 1997, pages S35-S58.

Appreciation of Risk Factors:

Arterial Disease: The usual risk factors for cardiovascular disease are of great importance in the assessment and long-term course of disease in patients with foot problems: obesity, diabetes mellitus, hyperlipidemias and hypertension. Weight loss reduces mechanical stress forces on the foot and ameliorates the biochemical and blood pressure abnormalities. Smoking is, of course, another major risk factor to be discouraged at every opportunity. The presence of vascular impairments, unfortunately, may promote circumstances that themselves become risk factors for peripheral problems. Stroke may decrease exercise and force unaccustomed use of the remaining intact parts. A decrease in cardiac output may accompany heart disease and further decrease flow in an arteriosclerotic foot. Hemodialysis is commonly associated with episodes of dehydration and hypotension during which the feet are elevated (and pulse-less) to maintain cerebral blood flow. Finally, other diseases or their treatments may compromise blood flow. Rheumatoid arthritis, for example, especially when associated with nodules, may be accompanied by vasculitis and leg ulcers. Long term treatment with glucocorticoids is associated with skin fragility and accelerated arteriosclerosis. Warfarin therapy may be complicated by the purple toe syndrome and microthromboemboli.

Venous Disease: A positive family history, occupations requiring quiet standing and factors impeding venous return (obesity, pregnancy and thrombophlebitis) clearly promote the development of varicose veins. Dilatation of the veins may promote incompetency of the venous valves further promoting enlargement of the veins and incompetency of the valves. Dominantly inherited clotting disorders may promote recurrent episodes of phlebitis; deficiencies of protein "C", protein "S" and antithrombin III are to be considered in such patients who may require long-term anticoagulation therapy.

Neuropathic Disease: Poorly controlled diabetes is the most common cause of neuropathic foot ulcers seen in the United States. However, we have seen and others have described neuropathic foot lesions in patients with other conditions: pernicious anemia, chronic alcoholism, old spinal cord injuries, myelodysplasia, syringomyelia, tabes dorsalis, leprosy and hereditary sensory syndromes (1). Other causes of peripheral neuropathy may require consideration in some patients: poisoning due to heavy metals or organic chemicals, drug toxicity, inflammatory states, collagen diseases, uremia, porphyria, acromegaly, beriberi and pyridoxine deficiency or excess.

Shoewear: Health persons should have shoewear that promote healthy and properly proportioned feet. A common unfortunate habit, for example is the use of shoes with high heels and pointed toes; gravity tends to force the foot into the pointed toe which squeezes the first and fifth toes inward possibly dislocating the toes over time and producing bunions. Such stresses are especially important in patients with high risk feet due to the various factors listed above and summarized in Table 1.

Table 1
Checklist for Risk Factors
Risk Factor Goal
Smoking None
Glycohemoglobin Normal range
Endocrine visits Enough to normalize Hgb A1C
Systolic blood pressure <130 mm Hg
Total Cholesterol <200mg/dl, lower better
Body Mass Index (Kg/M2) Male <27, Female <26
Shoewear Appropriate fit
Drugs and other diseases Minimal use of steroids and vasoconstrictors

Documentation of Symptomatology and Activity Level
Walking Capacity: Notation of the walking capacity is especially helpful in older patients who may forget their presenting limitations (e.g. a wheelchair) and complain later to you that your treatment has not helped them because they cannot walk an 18-hole golf course. We have found the walking questionnaire of Regensteiner et al helpful in this regard (Table II)(2). The location of the pain (whether in thigh, buttock, calf, arch or toes) should be noted. Again, any maneuvers that help relieve the pain should be observed (quiet standing, sitting, exercise, leg elevation, leg dependency or massage).

Work Status: Records of the occupational status of the patients are helpful in appreciating the shear forces applied to the foot and in properly filling in disability forms. It is helpful to note if the patient is working full-time or part-time, if the leg problem is making work difficult or impossible and what activities their occupation requires.

Differential Diagnosis of Claudication: Walking impairment may have causes other than arteriosclerosis obliterans: pain due to degenerative joint disease in the extremities or in the back, ataxia's, weakness, lymphedema, venous stasis and pain with stress fractures in the foot. Ischemic rest pain may be confused with gout. Claudication may be confused with spinal stenosis. The pain of "pseudoclaudication" in the patient with spinal stenosis not only develops in walking a specific distance but also occurs with quiet standing an equal length of time and may be relieved by straightening the back on sitting.

Varicose Veins: Varicose veins may explain chronic troublesome symptoms in many patients referred for leg evaluations. Lofgren listed aching (71%), swelling (60%), heaviness (47%), cramps (39%), itching (30%), cosmetic dissatisfaction (25%), stasis dermatitis (16%), pigmentation (16%), burning (16%), ulcers (8%) and cellulitis (6%) and his 350 patients (3).

Documentation of Physical Findings

Physical findings are important as pointers to the proper diagnosis, as means to document the progression of disease, occasionally as legal evidence and as a necessity for payment of insurance claims for tests and treatments. The presence of gangrene, limb hair loss, skin color changes, petechiae, blistering, mottling, stasis dermatitis, tropic nails, cellulitis, lost pulses, edema, sensory losses, loss of muscle mass or strength and of ulcerations should be noted.

Gangrene: Gangrene due to necrotizing cellulitis is properly separated from gangrene due to uncomplicated ischemia. Areas of skin infected with Pseudomonas, for example, may quickly become purple to black while surrounding and distal skin remains health in color. Such infection must be aggressively treated early before further damage occurs and the foot may usually be salvaged. On the other hand, gangrene associated with ischemia is seen commonly proximally at pressure points (heels, malleoli and bunions) and distally in the toes. In the latter situation, pressure relief and bed position may become crucial.

Blanching and Rubor: The amount of blanching of the foot and toes on elevation is inversely related to the true blood pressure at the ankle. Care must be taken not to chronically elevate feet that blanch to avoid promoting ischemic necrosis. Lowering the feet from an elevated position to a dependent position is usually associated with a return of normal skin color within ten seconds. Further, the veins on the dorsum of the feet usually fill with fifteen seconds. As arterial insufficiency becomes more severe, these times may greatly lengthen. As tissue perfusion decreases and the oxygen tension drops, an increasing number of capillaries are patent and rubor develops. Areas of skin with no blood flow and incipient ischemic gangrene may remain white after many minutes. Immediate steps are necessary to avoid losing such areas.

Table II
Walking Impairment Questionnaire(2)

A. Walking Distance: For each of the following distances, report the degree of difficulty that best describes how hard it was for you to walk WITHOUT stopping to rest.

During the past week, how much physical difficulty did you have... None Some Much Did-not-do Score x Dist.=Factor
1. Walking indoors such as around your home? 3 2 1 0 ______x 20= _____
2. Walking 50 feet? 3 2 1 0 ______x 50= _____
2. Walking 150 feet? 3 2 1 0 ______x 150= _____
2. Walking 300 feet? 3 2 1 0 ______x 300= _____
2. Walking 600 feet? 3 2 1 0 ______x 600= _____
2. Walking 900 feet? 3 2 1 0 ______x 900= _____
2. Walking 1500 feet? (5 blocks or more) 3 2 1 0 ______x 1500= _____
Sum of Factors = ______

Patient Impairment Distance Score = Sum of factors/10,560 = __________
(10,560 = no impairments)

B. Walking Speed: These questions refer to HOW FAST you were able to walk ONE CITY BLOCK. Tell us the degree of difficulty required for you to walk at each of these speeds WITHOUT stopping to rest.
During the past week, how much physical difficulty did you have... None Some Much Did-not-do Score x Speed=Factor
1. Walking 1 block slowly? 3 2 1 0 ______x 1.5 = _____
2. Walking 1 block at average speed? 3 2 1 0 ______x 2 = _____
3. Walking 1 block quickly? 3 2 1 0 ______x 3 = _____
4. Running or jogging 1 block? 3 2 1 0 ______x 5 = _____
Sum of Factors = _____

Patient Impairment Speed Score = Sum of factors/3.45 = __________

Pulse records: Pulses are commonly graded 0 to 4+. Our method of grading has definitions allowing duplication of results by most observers: "0" = absent; "trace" = not sure but likely there; "1+" = definite but hard to find; "2+" = definite and easy to find; "3+" = palpable with light touch; and "4+" = visible pulsations. The firmness of the vessels is also recorded, hard vessels confirming the presence of atherosclerosis. Some observers are fooled by pulses in their own fingertips. Others may be fooled by foot tremor and the rhythmical movement of tendons. The presence of strong pulses in the feet is strong evidence against diagnoses of ischemic disease in the extremities and makes formal vascular testing unnecessary in most situations.

Vascular Laboratory
We use our vascular laboratory to document the pathology and therapeutic needs of our patients.

Venous testing: Venous Doppler studies and venous outflow studies are performed if the possibility of thromboembolism due to deep vein thrombi in the thigh or pelvis is considered. In questionable cases, the more expensive Duplex scans may also be obtained. In practice, we have not seen an embolus associated with therapy with the Circulator Boot. The forces playing on the large veins in ambulatory patients are likely greater than those applied by boot therapy making venous testing in ambulatory patients probably unnecessary. Patients with increased risk for thromboembolism, those at bedrest from congestive heart failure and the like, are best tested.

Arterial testing: In past years, we did segmental blood pressures and pulse volume determinations along with mapping of the Doppler velocity wave forms in the groin, midthigh, popliteal area, mid-calf and ankle for the superficial femoral, popliteal and tibial arteries respectively, In addition, we made tracings of the dorsalis pedis and involved metatarsal and digital arteries. Such studies are helpful in predicting the results of arteriograms (4) and in designing appropriate boot therapy but are time-consuming. The tests were also helpful in following the course of the patients and provided a source of encouragement to those with severe disease and a slow course. In recent years, the emphasis on cost-saving has limited the number and quality of tests being reimbursed by insurance carriers. We have, hence, arrived at the procedures summarized in Table III in evaluating patients referred for arterial insufficiency.

Immediate Ancillary Diagnostic and Therapeutic Procedures
In patients accepted for boot therapy full responsibility for wound care frequently is necessary. Abscesses may require aspiration or an incision and drainage procedure. Appropriate anaerobic and aerobic deep cultures are desirable. Thick callus should be removed. We may remove mummified tissue attempting to leave a thin layer of the necrotic tissue as a covering over potentially viable tissues. We do not perform deep or disfiguring debridements through potentially viable tissues lest the procedures themselves irreparable damage the tissues and extend the lesions. Rather, we rely on the local injection of antibiotics and the debriding effects of pumping the various lesions within the Mini-Boot with the foot immersed in multi-electrolyte solution and antibiotics. See Table IV. Hospitalization in no way guarantees proper daily care of the ischemic foot. Important routine orders are provided to both inpatient and outpatient services (Table V). Commonly used methods of wound classification are given in Table VI. When it has been deemed appropriate to initiate boot therapy, the technique whereby it is delivered is prescribed by the physician (Table VII). In general, the legs are kept horizontal in the treatment of lymphedema and stasis disease while they are made as dependent as comfortably possible in ischemic disease.

Table III
Vascular Assessments
  1. Initial history and physical: Is significant arterial insufficiency a possibility? What is the likely nature and location of vascular occlusions?
  2. Determination of urgency of treatment and danger of immediate tissue breakdown:
    1. Toe photoplethysmography tracings (PPG's:
      Normal tracings usually eliminate possibility of arterial disease sufficient to prevent wound healing and additional testing commonly not necessary. Flat tracing point to danger of tissue breakdown.
    2. Transcutaneous PO2 and PC02 levels:
      TcO2 levels below 20 mmHg are said to be associated with nonhealing. Levels below 10 have been commonly associated with progressing tissue necrosis in our experience. Very low TcPO2 and high TcPO2 levels associated with clear-cut PPG waveforms point to cellulitis, which in our experience may be quickly sterilized with infiltration of the tissues with appropriate antibiotics, administration of a broad- spectrum oral antibiotic and boot therapy; early treatment is desirable.
  3. Noninvasive determination of pathological vascular anatomy if proper prescription of boot therapy in doubt or need to determine possible benefit for bypass surgery (recent arteriograms not available): Segmental blood pressures and pulse volumes determinations and Doppler arterial mapping are considered. If renal function in doubt, and still a possible candidate for bypass, MRI arteriogram then performed.
  4. Arteriograms: Are never performed as a routine test in patients not disabled enough to consider vascular surgery or in patients with other disabilities severe enough to rule out surgery.

Table IV
Method of Treatment
  1. Hospitalize patient if septic, other medical or surgical necessities or initial need for multiple boot therapies.
  2. Drain any obvious abscesses. Limit debridements to removal of clearly dead tissue and loose protruding bone fragments.
  3. Stop the cellulitic process immediately.

    1. Administer either orally or intravenously antibiotics to prevent septic emboli.

    2. Soak ulcerated lesions and/or irrigate fistulas before first boot treatment with saline-dilute hydrogen peroxide solutions to remove pus and loose debris.

    3. Infiltrate abscessed or cellulitic tissue and osteomyelitic bone with antibiotics usually once daily (e.g. 40 mg gentamicin).

    4. If devitalized ulcerated area present, place foot in plastic bag of multielectrolyte solution (Sea Soaks) containing antibiotics. Avoid prolonged contact with saline.

    5. Place bagged foot in Mini-Boot and pump after each heartbeat (1:1) if a palpable pulse, after every other heartbeat (1:2) if no palpable pulse and after every 3rd heartbeat (1:3) if very ischemic foot. Pump 40 minutes to disseminate the injected antibiotic throughout the cellulitic area, to scrub the infected ulcer and breakup thrombi in the foot secondary to the cellulitic process.

    6. Repeat steps d-e three to four times daily if advanced infection.

  4. Establish need for vascular reconstruction: avoid booting on a leg with no arterial inflow.

    1. Consider angioplasty of the iliac or femoral artery, brachial-femoral bypass or aorto-femoral bypass to establish flow into the leg.

    2. In patients with a flat pulse volume at the ankle or no detectable Doppler arterial sounds at the ankle, consider obtaining an early arteriogram.

  5. Include in the area of the leg to be booted the ischemic area and a proximal six inches of well-vascularized leg. Patients with diffuse ASO and infected foot ulcers may receive the Mini-Boot therapy above (3b-f) and Long Boot treatments from groin to toes, groin to ankle or to midfoot as needed.
  6. Treatments are continued 3-4 times a day in the hospital or nursing home, once daily as an outpatient and tapered as healing progresses.

Table V
Routine Orders for Boot Patients with Arterial Insuffiency
Routine Orders Explanation
1. Bed position: Raise head of bed on blocks. Pubic area should be higher than toes. Blood does not run uphill. The toes may not get blood if they are elevated. Maximal blood flow in the foot is obtained with a 10degree slant.10
2. Pressure sores: Pressure should be removed from the heels and malleoli by some means(a Podus Splint, towels taped in place smoothly around the calf, etc.). Pad side-rails if the patient is at risk of catching the foot in them. In patients with low blood pressure in the feet, the weight of the foot itself against the bed may be sufficient to block blood flow into the skin and, thus, cause skin breakdown.
3. Foot boards or pillows: Placed under the blankets, they may keep weight off of the toes. The weight of bedding on ischemic toes may be painful and block the entry of blood into the toes.
4. Blankets: Make sure the patient is adequately covered so that his/her own blood can warm the legs. Even normal legs have a decrease in blood flow when the body core temperature drops. The speed of healing is decreased in cold tissue.
5. Bandages: Change bandages as needed to minimize dampness due to drainage, 1 to 4 times/day. Bandages should not be tight. Do not wedge gauze between toes. Bacteria can grow in wet bandages. The wet bandage macerates adjacent skin. Drainage can contaminate the bed, the room, and the attending nurse or aide. Blood does not nourish skin compressed by tight bandages.
6. Bathing: Open lesions are not to be wetted in a tub or shower. Carefully bag such lesions for a quick whole body shower (patient willing). The area of and around the lesions should be separately cleaned with sterile soap and water and rinsed with sterile water, saline or Sea Soaks. Bacteria, such as Pseudomonas, may commonly be cultured from the water nozzle of baths and showers. The fecal organisms of the patient may be expected to get in a bath.
7. Cultures: In addition to initial cultures, weekly cultures should be obtained if lesions continue to drain or if there appears to be any deterioration in the physical status of the lesions. Deterioration of a foot under treatment is more likely to be due to infection with a new organism or abuse of the foot than a falloff in blood flow (except in dialysis patients).
8. Hot and cold: Avoid exposing ischemic tissue to hot or cold environments. External heat (hot pads or sun from the window) increases tissue metabolism and need for oxygen and blood flow. Heat may promote death of borderline tissue.

Pages S41-S46 of Methods of Treatment.
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