Making a wound tracing, also known as the acetate method, is a popular and practical method for measuring wound area.
A tracing is a drawing of the wound shape. It can be made on acetate measuring sheets supplied by manufacturers for this
CLINICAL WISDOM
Measurement of Erythema in Darkly Pigmented Skin Skin color changes reported by clinicians and in the litera- ture27 indicate that, when infl amed, the skin color of darkly pigmented individuals darkens to an eggplant/purplish color (see Fig. 4.12). It can be diffi cult to differentiate darkening of infl ammation from hemosiderin staining. When this is the case, proceed with temperature and edema examinations.
For a full description of the assessment of darkly pigmented skin, see Chapter 3.
The following are guidelines for measuring the extent of infl ammation/trauma in darkly pigmented skin:
● Use natural light or halogen light, not fl uorescent light.
● Outline the margins of color change on the surrounding skin with a marking pen.
● Select a reference point for future measures.
● Measure using the greatest length and the greatest width or the clock method.
● Calculate the area of color change (as described for all length-by-width measurements).
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• The wound map tracing becomes the document on which assessment findings of tissue attributes are recorded.
A map key at the bottom of the graph form assigns let- ters to each tissue attribute, making this an easy way to describe the tissue in the drawing. The tracing is a paper- and-pencil instrument to track wound healing over time.
Note: The tissue attributes on the wound recovery form37 are the same as those represented in the SWHT described in Chapter 6.
• The wound tracing can be scanned into a computer, making a digitized measurement of the wound. The area can be calcu- lated, and the tracing can be stored on the computer.
Steps for Making a Wound Tracing
1. Place two acetate measuring guides or two pieces of plastic wrap over the wound, so that the bottom piece fi ts across the wound from 3:00 to 9:00, and the top piece fi ts from 12:00 to 6:00. This arrangement helps when separating the top layer from the bottom layer. Smooth each piece of plastic to remove wrinkles. Two layers are used to prevent contamina- tion of the layer on which the tracing is made. The layer that was in contact with the wound is discarded with infectious waste after the tracing is completed.
2. Draw an arrow on the plastic wrap in the location and direc- tion of the 12:00 position.
3. Trace the wound edges.
Optional Additions to Tracings
1. Draw any notable features within or around the wound SA, such as an outline of the necrotic tissue or exposed bone.
Label the features with a letter from the wound recovery form key.26
2. Mark areas of erythema or darkened darkly pigmented skin with broken lines around the wound SA.
3. Mark areas of necrotic tissue or eschar with diagonal lines.
4. Mark other features with circles and dots, and label them with letters.
5. Place the tracing so that the 12:00 arrow is in the conven- tional 12:00 position on the graph form, and tape it onto the graph form. Make sure the plastic is taut and free of wrin- kles. (See instructions for completing the wound recovery form below.)
6. Photocopy the wound tracing to create a permanent record.
Discard the graph with the plastic tracing.
7. Mark wound features with lines drawn at right angles to the feature and label.
purpose or household plastic wrap with a plastic transparency marking pen (the ink does not bead up). These can then be transferred to graph paper to determine size by counting the squares (centimeters). This is called planimetry. Using 1 cm graph paper to count squares has been reported to be quick, effi cient, and realiable.34,35 Compared with linear measurements with a ruler, there is less overestimation of the real wound area.
This method is most useful on wounds that are on fl at sur- faces, and it has limited usefulness for full-thickness wounds.
Accuracy of measurement with the tracing method depends on how carefully the wound edges are followed as the tracing is drawn. Greater reliability using planimetry has been found for wounds with edges that begin to approximate over a bed of granulation tissue.34 The method of measuring the wound area from transparency tracings and placing it on graph paper to determine size by counting the centimeters has shown high intratester and intertester reliability (0.99).
Repeated tracings show changes in the size and shape of a wound over the course of recovery. Tracing is easy to learn, inexpensive, readily available, and requires minimal training.36
Clean tracings taped to a sheet of paper can be stored in the patient record. However, because these tracings can come loose or become ragged, the tracing and form can be photocopied, with the photocopy stored in the chart.
Applications of Tracings
Following are ways that tracings can be used:
• Tracings show change in the wound perimeter shape over time. Wound shape is a helpful indicator of the rate of heal- ing. As described in Chapter 2, linear wounds contract rap- idly, square or rectangular wounds contract at a moderate pace, and circular wounds contract slowly.35
• When placed on a metric graph form (planimetry), trac- ings show the wound size, as well as the shape of the healing wound (Exhibit 4.7).
• A tracing can become a “wound map,” showing features of the wound bed, such as necrotic tissue, and adjacent tissue charac- teristics, such as erythema (see Exhibit 4.7). Household plastic wrap is better than a grid sheet for this because it is clear.
• When placed on metric graph paper, features such as the actual amount of undermining/tunneling around the wound perimeter can be drawn on the wound map using the actual measurements and a ruler.
RESEARCH WISDOM
Measuring Wounds of Different Shapes
A comparison of the standard error of measurement for wounds of different shapes using four techniques: linear ruler length and width, planimetry, stereophotogrammetry (SPG) length and width, and SPG area showed that linear ruler length and width measurements best measured circu- lar wounds, tracing worked best for pear-shaped wounds, and SPG had the lowest standard error of measurement for L-shaped wounds.34 SPG incorporates the use of enhanced digital photography with a computer system using wound measurement software.
CLINICAL WISDOM
Tracings on Plastic Sandwich Bags
A plastic sandwich bag can be placed over the wound and a tracing can be made on the top layer, with the bottom layer of the bag acting as a wound barrier. Slit the bag in half and discard the contaminated layer with infectious waste. The top layer can be put on a graph form or placed in a zippered sandwich bag to keep for comparison measurements. This method is very useful for home care.
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EXHIBIT
Wound Recovery Form with Tracing 4.7
NAME: DATE:
WOUND I.D. (1) (2) (3)
INFLAMMATION PROLIFERATION EPITHELIALIZATION X
B = BLISTER F = FIBROPLASIA EP = EPITHELIALIZATION E = ERYTHEMA C = CONTRACTION M = MACERATION H = HEMORRHAGIC FT = FULL THICKNESS R = REMODELED SB = SCAB PT = PARTIAL THICKNESS I = INTACT
N = NECROSIS U = UNDERMINING
DRAINAGE: DRAINAGE: DRAINAGE:
V = VISCOUS S = SEROUS S = SEROUS PU = PURULENT SS = SEROSANGUINEOUS DY = DRY
Adapted with permission from Sussman CA. Physical therapy choices for wound recovery. Ostomy/Wound Management. 1990;20:20–28, Health Man- agement Publication, Inc., Wayne, PA.
G. LUCKY 4/20/08 B Sweet
COCCYX
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Using a Wound Recovery Form
The wound recovery form37 is a paper-and-pencil instrument that consists of a centimeter graph sheet, a linear measure aligned with the graph coordinates to show size, and anatomic fi gures (front and back) to mark location. The tissue charac- teristics are listed by phase: infl ammation, proliferation, and epithelialization. You can use this key in evaluating and devel- oping the wound phase healing diagnosis and in tracking the recovery of the wound by phase and wound characteristics.
A completed form is shown in Exhibit 4.7.
The supplies needed for the wound recovery form include
• Wound recovery form
• Wound tracing
• Transparent tape
• Fine-tip marking pen
• Photocopier (optional)
The steps in creating a wound recovery form include the following:
1. Prepare wound tracing (see above).
2. Place tracing on wound recovery graph with the arrow aligned with lines at the 12:00 position.
3. Tape tracing in place unless it is adhesive backed.
4. Draw lines that are exactly the same length as the length measurements taken from the undermining at clock points around the wound perimeter, starting at wound edges and moving outward.
5. Draw lines from the tissue characteristics out to the side of the graph and label with letter from key.
HELPFUL HINTS
Tracings
A grid printed on acetate fi lm that peels off a plastic backing sheet can be used to make wound tracings. The sheet acts as a barrier to infection and is discarded. The tracing is then ready to place in the medical record.
6. Print wound location at the bottom of the picture. Mark its location on anatomic fi gures.
7. This “wound map” is also a tissue assessment report.