Lesson 5
Casts

INTRODUCTION

a. A cast is a device used for immobilization. Cast materials include plaster of Paris, fiberglass, and plastic. All come in rolls that can be applied in a manner similar to using an Ace bandage. Plaster casts are heavy, dry slowly, and lose strength and integrity if they become wet. Fiberglass and plastic casts are light in weight, dry quickly, and can be immersed in water and redried; however, they are expensive and may macerate underlying skin. Casts are usually applied by a trained orthopedic specialist under the supervision and direction of a physician.

b. Casts are used for several purposes.

(1) To immobilize fractures and hold bone fragments in reduction (placement for healing).

(2) To prevent movement in soft tissue injuries.

(3) To maintain proper alignment and correct deformities.

(4) To permit early mobilization.

TYPES OF CASTS

a. Short leg cast--extends from below the knee to the base of the toes.

b. Long leg cast--extends from the upper or middle thigh to the base of the toes.

c. Short arm cast--extends from below the elbow to the palm.

d. Thumb spica or gauntlet cast--extends from below the elbow to the palm and includes the thumb.

e. Long arm cast--extends from axilla to palm, with the elbow normally immobilized at a right angle.

f. Walking cast--a short or long leg cast with a rubber or metal walking device attached to the foot.

g. Body cast--encases the trunk.

h. Shoulder spica cast--a body cast that encases the trunk, shoulder, and elbow.

i. Hip spica cast--a body cast that encases the trunk and one or both lower extremities.

CARE OF THE PATIENT WITH A NEWLY APPLIED CAST

a. Expose a newly applied cast to air circulation. It should never be covered, because the cover will restrict the escape of moisture and heat. This is essential, as a drying cast generates heat within the plaster as the moisture evaporates and the cast hardens.

b. Handle a wet cast carefully. A newly applied cast is set and firm when the patient leaves the cast room, but it is still damp and easily damaged. It takes 24-48 hours for a cast to become dry and hard. Handle the cast by lifting and supporting it on a pillow or with the palms of the hands. Never use fingers as they will leave indentations, which cause pressure areas within the cast.

c. Provide plastic-covered pillows to support the cast along its entire length. Never permit the wet cast to rest directly on a flat or firm surface as this will flatten the contours of the cast and cause pressure within the cast.

d. Review the patient's clinical record for the type of cast and the reason the cast has been applied. Interview the patient to determine his knowledge of the cast purpose and whether he has had a cast before. Instruct the patient on care of the cast that is wet and after it is dry.

e. After a cast has cooled and begins to harden, elevate the casted extremity to reduce swelling which often occurs after application of a cast. When a newly applied cast is elevated, it should be supported along its entire length, on an inclined plane, with the distal joints higher than the proximal joints. For example, hand higher than elbow, elbow higher than shoulder.

f. Observe all edges of the cast for any areas that cut or put pressure on the skin.

g. Observe the extremity encased in plaster for circulatory impairment by comparing fingers or toes of the casted extremity with the uninvolved extremity. The primary concern following new cast application is to prevent complications. Circulation should be checked hourly during the first 24 to 48 hours, then every 4 hours.

(1) Check the skin temperature of the injured extremity. It should not be colder than the unaffected limb.

(2) Check and compare the pulses. They should be equal

(3) Check for complaints of numbness, tingling, burning, swelling, pain, pressure, or inability to move the fingers or toes.

(4) Report presence of the above signs and symptoms IMMEDIATELY to avoid possible tissue necrosis; these findings indicate possible ischemia.

h. Perform the blanching (capillary refill) test. The nail beds of the fingers or toes are compressed lightly and released to check how quickly the color returns.

(1) With pressure applied, the nail bed should turn pale (blanch). When pressure is released, the color should return within the time it takes to say "capillary refill," indicating return of capillary action.

(2) Failure to blanch, or a blue tinge, indicates impaired venous circulation and congestion of tissues.

(3) Failure of color to return, or cold, pale fingers or toes suggests impaired arterial circulation.

(4) In either case, report findings IMMEDIATELY. Do not wait. Permanent damage can result from impaired circulation caused by cast pressure.

FINISHING THE DRY CAST

Cast edges may have been trimmed and finished with a smooth edge at the time of application or edges may be finished after the cast is dry.

a. When a cast is lined with stockinette, it may be pulled out from within the cast and folded back over the edges of the cast and taped in place. See figure 1-12.

b. Adhesive tape or moleskin may be used to cover rough edges of the cast by applying overlapping pieces in a "petal" fashion. See figure 1-12.

Figure 1-12. Finishing a cast.

c. Nursing implications. A cast without a smooth, unwrinkled finish is a potential source of problems.

(1) Rough, unfinished cast edges will scrape or cut the skin. Broken skin surfaces may become infected.

(2) Loose bits of plaster from an unfinished cast may become lodged inside the cast, causing itching and irritation.

(3) Wrinkled or "bunched-up" edging may result in pressure areas and potential skin breakdown.

CAST CUTTING

Casts may be cut for different reasons--to allow for wound dressings, to examine a painful area, or to relieve pressure. Nursing personnel may be required to assist with cast cutting at the bedside as an emergency measure.

a. Bivalving the Cast. Bivalving is the recommended method for emergency cutting to relieve pressure. In bivalving, the cast must be cut along its entire length on two sides (medial and lateral) and the base lining or padding cut completely down to the skin. If the cast or the lining is split only part way, the congestion will be increased and additional tissue damage will occur. To cut the cast, use a knife, a hand cutter, or an electric cast cutter. Use bandage scissors to cut the base material. To use a knife for emergency cast cutting, follow these steps.

(1) Make a shallow groove to indicate the cutting lines on both sides of the cast.

(2) Apply water or peroxide along the cutting lines to soften the plaster. Use a syringe to apply.

(3) With the knife, cut through the layers of plaster along the cutting line. Do not attempt to slice through all layers at once and do not use the knife to cut through the base material.

(4) With the bandage scissors, cut through the base material down to the skin. Cut every thread of the lining material completely through since the lining is sometimes the source of the trouble.

(5) Use tape or an elastic bandage to loosely hold the bivalve cast together in order to maintain support of the casted part until further instructions are obtained.

b. Windowing the Cast. This procedure is done on specific order of the physician. It is a potentially dangerous procedure because the underlying tissue may bulge through the window opening, causing "window edema." If a window is cut, the piece of plaster removed should be saved.

(1) The physician indicates the area to be windowed.

(2) The physician or orthopedic technician cuts the window, usually a square or rectangular area, out of the cast. Once the plaster has been cut out, the lining material is carefully cut away from the skin.

(3) After the physician examines and treats the underlying area, a dressing may be applied over the exposed skin area and the cutout piece of plaster bound in place again. Replacing the cutout plaster section will prevent window edema.

GENERAL NURSING MANAGEMENT OF THE PATIENT WITH A CAST

a. Although a patient with an arm or leg cast is much more self-reliant than a patient in a body or spice cast, it is a nursing responsibility to monitor all patients and assist as needed. Nursing management includes the following actions to assess the effectiveness of the cast.

(1) Check the edges of the cast and all skin areas where the cast edges may cause pressure. If there are signs of edema or circulatory impairment, notify the charge nurse or physician immediately.

(2) Slip your fingers under the cast edges to detect any plaster crumbs or other foreign material. Move the skin back and forth gently to stimulate circulation.

(3) Lean down and smell the cast to detect odors indicating tissue damage. A musty or moldy odor at the surface of the cast may be the first indication that necrosis from pressure has developed underneath.

(4) Check the integrity of the cast by looking for cracks, breaks, and soft spots.

b. The casted body part must be examined and assessed frequently in order to prevent complications. Assess the casted part by checking the following.

(1) Assess circulation by performing the blanching test and comparing the skin temperature and blanching reaction of the affected limb to that of the unaffected limb.

(2) Assess the presence of sensation in the affected limb by touching exposed areas of skin and instructing the patient to describe what he felt.

(3) Assess the motor ability of the affected limb by having the patient wiggle his fingers or toes.

c. Patient education will do much to prevent complications. Instruct the patient to do the following.

(1) Avoid resting cast on hard surfaces or sharp edges that may dent the cast and cause pressure areas.

(2) Never use a coat hanger or other foreign object to "scratch" inside the cast. This may cause skin damage and infection.

(3) Report any danger signs to the nursing staff immediately. Danger signs include pale, cold fingers or toes, tingling, numbness, increased pain, pressure spots, odor, or feeling that the cast has become too tight.

(4) Report any damage to the cast such as cracks, breaks, or soft spots.

(5) Never attempt to remove or alter the cast.

NURSING MANAGEMENT OF PATIENTS WITH EXTREMITY CASTS

a. After a leg cast is applied, prevent or alleviate swelling by elevating the extremity above the level of the heart. After the patient begins to ambulate, he should be encouraged to elevate the casted extremity when he is seated or resting in bed.

b. To control swelling with an arm cast, elevate the extremity on pillows or suspend in stockinet from an IV pole when the patient is lying or sitting. When the patient is ambulatory, a sling may be used for support. The type of sling required will depend upon the type of cast applied. A standard short arm cast or long arm cast can normally be adequately supported with the triangular bandage sling. See figure 1-13. [Note: Cast is not shown.] A sling does not support the arm above heart level so, in order to promote drainage and reduce swelling, the patient should be encouraged to remove the sling and raise the arm above his head periodically.

Figure 1-13. Triangular bandage sling.

 

c. If permitted by the physician, the patient should be encouraged to exercise his muscles. Isometric muscle contractions (contracting the muscle without moving the part) may be done to prevent atrophy and maintain muscle strength.

(1) If the patient is in a leg cast, have him lie down, place your hand under his knee and instruct him to "push down" toward your hand.

(2) If the patient has an arm cast, instruct him to make and release a tight fist.

(3) Encourage the patient to wiggle his fingers and toes frequently.

NURSING MANAGEMENT OF PATIENTS WITH BODY OR SPICA CASTS

a. When a large cast, such as a body cast or spice cast, is applied, the curves of the cast must be supported in order to prevent sagging and pressure. Support should be given to the entire cast, especially at weak areas such as the shoulder, hip, and knee. Small plastic-covered pillows should be placed under the cast in such a manner that there are no gaps between pillows.

b. A patient in a large cast will not be able to bathe without assistance. However, the patient must be encouraged to do as much for himself as is possible. Nursing personnel assist with those hygiene needs that the patient cannot manage alone. Each time the patient is turned to the prone position, wash the exposed back and buttocks and dry thoroughly. Apply lotion or powder and gently massage the skin to stimulate circulation.

c. When assisting with a urinal or bedpan, elevate the back and shoulders slightly higher than the buttocks to prevent dampening or soiling of the cast. Pillows may be used for support or, if the physician permits, the bed may be gatched up.

(1) Assist male patients with placement and removal of the urinal, if necessary.

(2) An emesis basin, slipped in place lengthwise, may be used by female patient for voiding. The basin is easier to place and remove than a bed pan.

(3) When assisting a patient with a bedpan, be certain that the buttocks are resting on the rim of the bedpan. The patient's head, shoulders, and back should be higher than the buttocks if at all possible.

(4) When a trapeze can be used, instruct the patient to lift straight up in order to avoid friction on the skin when placing and removing the bedpan.

(5) After using the urinal or bedpan, assist the patient to clean himself thoroughly. Check cast edges for soiling or dampness.

TURNING A PATIENT IN A SPICA CAST

Patients in body or spice casts must be turned from supine to prone to permit the cast to dry, to prevent pressure areas by redistribution of body weight, and to prevent respiratory and urinary complications. The patient is turned initially as ordered by the physician and must usually be turned a minimum of every two hours (unless otherwise indicated by the physician) for as long as he remains in the cast. Until the cast is thoroughly dry, at least three people should turn the patient so that there is no strain on the patient or on the damp cast. As the patient becomes accustomed to the cast and learns to help himself, less assistance may be required in turning the patient.

a. In any turning procedure, the patient must be turned "as a unit" with the affected side ("bad side") uppermost. The patient should be turned, or log-rolled, toward the unaffected side of his body ("good side").

b. Utilizing the pillows on which the patient is resting, and/or a draw sheet, move the patient to the side of the bed with a steady, even, pulling motion. Remember that the patient must be moved as a unit. When the patient is in the proper position, his "bad side" will be at the edge of the bed and his "good side" will be near the center of the bed.

c. One person should remain at the patient's affected side, while the others move to the opposite side of the bed to straighten the bed linen and position another set of pillows along side the patient. The pillows should be arranged so that they will support the cast and the patient's head and shoulders when you turn the patient.

d. The patient should be instructed to raise the arm on his unaffected side above his head.

e. The person on the patient's affected side should place his hands, with palms up, under the patient's torso.

f. The assistants on the patient's unaffected side should reach across the bed and place their hands, with palms down, on the patient's affected side. The person nearest the patient's head should place his hands on the patient's shoulder while the person nearest the patient's feet should place his hands on the patient's hip and leg.

g. Moving simultaneously, the person on the patient's affected side should gently draw the patient toward himself while the assistants on the opposite side ease the patient over toward themselves. Care should be taken to support the leg and arm on the affected side of the body.

h. After the patient has been turned, check the placement of the supporting pillows. Be sure that there are no gaps between pillows. When the patient is turned to the prone position, place a pillow under the lower legs to allow the feet to rest in the position of function and avoid having the toes pushed against the mattress.

i. Position a pillow under the patient's head and shoulders and be sure to place the call bell within his reach.

PATIENT CARE AFTER CAST REMOVAL

a. After a cast has been removed, continue to provide support to joints and normal body curves. The muscles will have become weakened from disuse and, although movement is encouraged, support is necessary. Use firm pillows to support the patient while in bed and use elastic bandages or an arm sling, if necessary, when the patient is up and about.

b. Avoid vigorous attempts to remove skin exudate and crusts of dead skin cells, which are present when a cast has been in place for several weeks. Gentle soaking and applications of oil to soften the skin and loosen crusts may be recommended.

c. After the cast is removed, the physician or physical therapist may prescribe exercises to increase strength. If the patient has been doing isometric muscle contractions, he will not have to "relearn" to contract his muscles and will progress more rapidly through rehabilitation. Atrophy of the part may be noticed, but this should gradually disappear with the return of muscle function. Swelling may develop for a while, but decreases with improved muscle tone and circulation as the patient becomes more active.

End of Lesson 5

Next Lesson
Home Page