FIGURE 3.19 Shallow and irregularly shaped lesion with a good granulating base. The associated physical signs of chronic venous insuffi ciency, such as hyperpigmentation, chronic scarring, and skin contraction in the ankle region, are readily identifi ed. Note the clas- sic characteristics of venous disease: (1) Irregular edges, (2) Shallow ulcer, (3) Evidence of hyperpigmentation (hemosiderosis), (4) Loca- tion above the medial malleolus. (Copyright © C. Donayre.)
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CLINICAL WISDOM
Assessment of Hair Distribution as an Indicator of Peripheral Circulation
1. An easy checkpoint for adequate tissue perfusion to the lower extremities is examination of the great toes for hair growth. Hair growth on the great toes implies adequate circulation to support the hair follicles. When working with female patients, remember to ask if they shave the hair on their great toes.
2. Move up the leg proximally from the ankle and assess the most distal point at which hair distribution stops. Next, palpate for skin temperature and pulses, and observe skin color in any areas denuded of hair for circulatory changes.
8/26 – MM
A
1 8/31 – MM
B
10/8 – MM
C
1
FIGURE 3.20 A: Unstageable bloody fi lled blister. Legend should change to leave off day of identifi cation. B: Same wound as in (A).
Note apparent necrosis without blister roof. Note area of sDTI.
C: Same wound as in Figure 3.20a with the blister opened and it is now stageable. Category/Stage III pressure ulcer. Note area of sDTI.
(Copyright © C. Sussman.)
and ruptures blood vessels, the fl uid can be bloody or brown (Fig. 3.20A). The blister roof is nature’s best dressing, but it can hide deep tissue damage (Fig. 3.20B). Removal of the blister roof is controversial. If the blister fl uid is clear, tissue damage may not extend into the dermis or deeper; the wound will likely heal under the blister roof, and the epidermis will eventually fall off. The blister roof should not be disturbed and, in fact, may require protection. However, if the fl uid is bloody, brown, or cloudy as in Figure 3.20A, deep tissue damage may be present, and unroofi ng the blister can be the only way to determine the extent of trauma (Fig. 3.20B). Ultrasound technology to iden- tify depth of tissue edema and trauma, such as under a blister, is being tested with good outcomes (see Chapter 26).
Assessment of the tissue under the blister without breaking the blister is helpful in evaluating when the blister needs to be unroofed. The validity of using digital palpation to determine tissue resilience (i.e., less resilient or less stiff compared with
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normal area before applying to possible insensate areas to avoid burns. Research reports that the lateral aspect of the foot is the area most sensitive to thermal sensation.102 If a patient is unable to sense warmth, he or she is at high risk of burns if heat is applied to the skin. Testing for cold can be performed by apply- ing a cold tuning fork. If a patient is unable to sense cold, he or she is at risk for injury from exposure to cold; the feet should be protected from frostbite if the patient is going to be exposed to very cold temperatures. Thermal allodynia can also be detected in hypersensitive areas.
Vibratory Perception Threshold
VPT is a measure of progressive PN for aging adults and indi- viduals with immune-mediated polyneuropathies including diabetes. In all groups, VPT is better perceived in the upper extremities compared with the lower. There is a signifi cant age- related decline in VPT at all locations. VPT is recommended as a part of routine neurologic examination, as well as for patients with diabetes and other risk factors for skin ulceration.103,104
VPT testing is simple and easy to perform with a 128 Hz tun- ing fork.103–105 The simplest method is the on/off method, which is reliable for testing VPT at the foot.105 The test procedure is as follows:
1. Before testing the VPT at the foot, give the patient a pre- liminary test by placing the vibrating tuning fork on the sternum, so that the vibratory sensation can be readily recognized.
2. Ask the patient to shut the eyes and keep them closed.
3. Ask the patient to report the start of the vibration sensation and the cessation of vibration (on-off).
4. Strike the tuning fork and place it on the bony prominence on the dorsum of the great toe proximal to the nail bed.
5. Repeat the test eight times at the same location, recording the on/off report.
6. VPT is defi ned as “the total number of times the application of the vibrating tuning fork and the dampening of vibration was NOT felt. Scores can range from 0–8.”105
Note that VPT is a screening test used to predict risk for ulcer- ation, rather than a wound assessment technique. Screening is recommended annually for patients without neuropathy and every 6 months for individuals who have neuropathy but do not have deformity or vascular disease. Patients who have neu- ropathy with deformity or vascular disease diagnoses should be evaluated every 3 months. If ulceration is part of the patient history, evaluation should be performed every 1 to 3 months.106 Any patient identifi ed as having abnormal values at screening should be referred for further medical workup and special edu- cation, such as foot care education programs, as described in other chapters. VPT results are a trigger to evaluate candidates for this intervention, as well as to validate the outcome of the intervention.
Skin Temperature
Baseline skin temperature is one objective measurement of cir- culation that can be used to evaluate infl ammation, and diag- nose infection and monitor circulatory response to treatment.
Local body temperature can be tested by palpation, with a thermistor, liquid crystal skin thermometer, or with an infrared thermometer.
adjacent tissue) has been demonstrated. Gently press down with a fi ngertip on the tissue beneath the blister roof and compress it.
Release and feel for the resiliency of the subcutaneous tissues. If there is good resilience (i.e., it bounces back when the pressure is removed), the deep tissues may be mildly congested. However, if the tissue feels soft, spongy, or boggy, there is high probability of tissue congestion and probable necrosis.85 The common term for this characteristic is “mushy” or “boggy.” Practice and care- ful concentration are needed to perform this palpation examina- tion. One tip is to try pressing the skin down on the contralateral location (e.g., on the heel) to compare the resiliency.
Sensation
Sensory testing procedures and expected outcomes are described in this section. They include pain, protective sensa- tion, thermal sensation, and VPT.
Pain
Accreditation standards for health-care facilities in the United States require each patient’s pain to be measured regularly and proper relief supplied.99 Severe pain or tenderness, either within or around the wound, can indicate the presence of infec- tion, deep tissue destruction, or ischemia. In recognition of the signifi cant effect of pain on wound healing and wound man- agement, Chapter 22 is devoted entirely to that topic, address- ing the issues of wound pain and wound healing, including pain physiology, pain issues, pain assessment, and treatment strategies.
Protective Sensation
Testing for protective sensation, defi ned as loss of the ability to feel or perceive a minimal amount of touch/pressure using Semmes-Weinstein monofi laments, is indicated if sensory loss is suspected. Neuropathy from many causes, including diabe- tes, Guillain-Barré syndrome, alcoholism, chemotherapy, and Charcot-Marie-Tooth disease, results in the loss of protective sensation. A minimal protective sensation threshold is the key to protecting the neuropathic foot from ulceration.
A safe, accurate method for testing protective sensation has been developed using Semmes-Weinstein monofi laments.100 The monofi laments come in different force levels. Levels 4.17, 5.07, and 6.10 are used to check for protective sensation. Force levels increase as the numbers increase. The object of the test is to determine if the patient can detect pressure when the monofi lament is placed against the skin and the force applied is suffi cient to buckle the monofi lament. Testing is usually per- formed on the sole of the foot. The inability to sense the 5.07 monofi lament is the threshold for loss of protective sensation and indicates a limited ability to use protective sensations. If the patient can distinguish this level of sensation at several points on the feet, the sensation is considered to be adequate to avoid trauma.101 Many individuals with PN do not feel the largest monofi lament (6.10), which indicates a loss of protective sensa- tion of 75 g. This fi nding should trigger the prompt referral to a specialist for appropriate protective footwear and should be followed closely (see Chapter 12).
Thermal Sensation
The test for thermal sensation is performed using test tubes or small narrow bottles fi lled with warm water. Be sure to test in a
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7. For large wounds, measure at the wound edge at the 12:00 and 6:00 positions and near the expected outer margin of the periwound erythema/discoloration. Repeat at the 3:00 and 9:00 positions.
8. For small wounds, measure by placing the liquid crystal strip across the wound diameter.
9. Record temperature at each point.
Infrared Thermometer
A radiometer or infrared scan determines temperature by measurement of surface refl ection of infrared radiation. These devices can reliably be used in the clinic with minimal training.
In addition, personal infrared thermometers may prove to be an effective means of reducing risk of ulceration in high-risk patients by providing an easy-to-use tool that encourages vigi- lant monitoring, provides immediate feedback about a pending problem, and empowers the patient to take action when change is measured. Chapter 12 has explicit directions for use of the infrared scanner.
Utility of Skin Temperature Assessment
Skin temperature is a useful measure for assessing many types of wounds and tissue status including the following situations:
Surgical wounds. Changes in wound temperature are readily apparent during the fi rst 8 postoperative days. During the fi rst 3 postoperative days, the temperatures of the wound and adja- cent tissues are typically the same. However, by postoperative day 4, there should be a discernible change, with the tempera- tures of the wound and surrounding tissues decreasing gradu- ally. Zones of warmth around the wound become narrower, with signifi cantly greater warmth over the incision than in the surrounding tissues. The heat measured in adjacent skin areas is not an infl ammatory reaction; rather, it is reactive hyper- emia. Hyperemia is the consequence of humoral substances released from cellular damage at the time of wounding—
chiefl y histamine—and pain that triggers neurogenic reactions, including vasodilation.109 Only a narrow zone adjacent to the wound is due to infl ammation. During the early postoperative period, the two areas are indistinguishable from one another.
As the wound heals, the area of warmth narrows, decreases in temperature, and represents the area of true infl ammation.
Wound temperature depends on the degree of vascularity of the tissues: a higher grade of vascularity will result in a higher tissue temperature.109 If the expected outcomes (i.e., that the wound and adjacent skin temperatures decrease by the fourth postoperative day) are not met, this indicates that the wound is not healing as expected and secondary intention healing (see Chapter 2) is imminent because of tissue necrosis or bacterial contamination.109
Infl ammation. An increase in skin temperature of 4°F com- pared with the contralateral side110 can indicate infl ammation that has not manifested on the surface, such as a pressure ulcer over a bony prominence or the presence of infection (e.g., an abscess) or Charcot arthropathy (see Chapter 12). It is a very useful tool for assessing infl ammation and wounding in darkly pigmented individuals in whom the margins of erythema are diffi cult to see. Skin temperature can be measured at loca- tions on the margins of discoloration and at the center over the bony prominence. The clock method (i.e., measuring the temperature at the 12:00, 3:00, 6:00, and 9:00 positions around Palpation
Palpation using the assessors hands is a subjective measure- ment of skin temperature, which has limited reliability detect- ing subtle differences in skin temperature.107,108
Thermistor
Temperature can also be measured using a thermistor, which is a probe placed against the skin that takes a reading. These devices are diffi cult to attach to the body surface resulting in poor surface contact, which limits the accuracy of the read- ings and take signifi cant time to equilibrate.108 Therefore, these devices are not recommended for assessment purposes.
Liquid Crystal Skin Thermography
A liquid crystal skin thermometer is a thermosensitive strip that changes color in a few seconds after contact with the skin to indicate skin temperature. It is a semiquantitative method that relies on color to measure periwound and adjacent skin temperature.
Liquid crystal strips are available with different temperature ranges. Use of an inexpensive liquid crystal skin fever ther- mometer strip that changes color with temperature change is a simple, accurate, and useful way to assess the temperature of periwound skin. These devices are reliable and have been clini- cally tested for evaluation of primary wound healing status of surgical wounds. The method is quick, simple, reliable, and inexpensive.109 Strips are available with a range of 80°F to 100°F (26°C–38°C).
A higher temperature of both periwound and adjacent skin measured on the liquid crystal compared with contralateral area is an indication of increased circulatory perfusion. This is the heat described as a classic sign of infl ammation, which includes hyperemia associated with increased blood fl ow but can also be an indicator of infection.108 Assessment and judgment of an experienced clinician are needed to make an appropriate diagnosis. Cooler periwound skin temperature compared with adjacent and contralateral skin should be considered an indica- tor of wound chronicity.
The procedure for measuring skin temperature with a liquid crystal strip is as follows:
1. Ensure that the area of skin to be tested has been pressure- free and exposed to ambient air temperature for at least 5 to 10 minutes before testing. (A sheet can cover the patient for privacy and to avoid chilling.)
2. Dry the skin of sweat before each measurement, because moisture on the skin considerably modifi es the image.109 3. Place a single layer of plastic against the skin as a hygienic
barrier (this does not interfere with temperature accuracy).
This step and the following can be eliminated if the strip is disposable. Strips can be reused for a single patient if the barrier is used.
4. Lay the temperature strip fl at on the plastic barrier.
5. Hold the strip in place at both ends lightly, to avoid com- pressing capillaries. Wait for the color of the strip to change, allowing at least 1 full minute for the change to occur. In very infl amed tissues, color change can occur immediately, but it may change more as it is held for the full minute.
6. Read the temperature while the strip is still against the skin.
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