AORN JOURNAL NOVEMBER 1985, VOL 42, NO 5

Sternal Wound Complications NURSING CARE FOR CORONARY SURGERY PATIENTS

Julie Marshall, RN; Christine Conkey, RN

ternal wound complications following cardiac surgery occur infrequently, but are S a serious and sometimes fatal development.

For the perioperative nurse, preventing compli- cations by identifying patients likely to develop them is an important concern.

In one series of 4,124 patients, the incidence of complications following median sternotomy was 1.8%. Nineteen patients (0.5%) died as a result of sternal wound complications. Septicemia and mediastinal abscesses were found in all fatal cases.’

Case Study

.T., a 66-year-old female, was admitted to the cardiovascular unit with unstable M angina. She had a 20-year history of

pressing chest pains that had become more frequent in recent weeks. The pain was associated with dyspnea, diaphoresis, nausea, dizziness, and occasional syncopal attacks. She had two-pillow orthopnea and occasional paroxysmal nocturnal dyspnea but denied pedal edema. A physical exam showed obesity and a cholesterol level of 296 mg/ dL, but was otherwise unremarkable.

Cardiac catheterization revealed a 95% narrow- ing of the proximal left anterior descending coronary artery and a 90% narrowing of the first diagonal branch. She developed severe chest pain during the procedure and underwent emergency two-vessel coronary bypass surgery. Her postop erative course was complicated by sternal wound infection with sternal instability. Two surgical debridements during the first three postoperative weeks were unsuccessful in eradicating the

infection. Wound care included continuous irrigation with

povidone-iodine solution using a closed drainage system and sterile dressing changes at least four times per day.

But problems set in. Morganella morganii and enterococci were found in a wound culture. Vancomycin hydrochloride 500 mg every six hours followed by cefamandole nafate 1 mg every six hours controlled the patient’s elevated body temperature, but not the infection. A chest x-ray taken on the 48th postoperative day showed mediastinal widening suggestive of aortic aneu- rysm. Six days later the patient returned to surgery for mediastinal exploration and another wound debridement. However, when the sternal suture wires were removed, profuse mediastinal bleeding developed. Efforts to control it were unsuccessful;

Julie Marshall, RN, MS, is a nurse practitioner and teacher in cardiovascular nursing in the OR and surgical nursing department at Rush-Presbyterian St Luke’s Medical Center in Chicago. She is also an instructor at the Rush University College of Nursing. She earned her master of science degree. at Boston College and her bachelor of science in general nursing at Northern Illinois University in Chicago.

Christine Conkey, RN, MSN, is a staff nurse in the cardiovascular OR at Rush-Presbyterian St Luke’s Medical Center in Chicago. She earned her master of science degree in nursing at Rush University in Chicago and her bachelor of science in nursing at the University of Iowa in Iowa City.

The authors wkh to acknowledge Inchul Lee, MD, who performed the patient autopsy in the case sluay.

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The ascending aorta had developed a false aneurysm that

ruptured into the abscess.

the patient died on the operating table. An autopsy showed sternal tissue softening and

necrosis with a poorly defined retrosternal abscess. The ascending aorta had developed a false aneurysm that ruptured into the abscess. The liver contained scattered microabscesses consistent with septic embolization. Postmortem blood and sternal wound cultures yielded M morganii and entero- cocci. Also noted was cardiomegaly and throm- bosis of the diagonal graft. The other graft was intact; no scars or infarcts were present.

Rkk Factors

he range of complications encompasses a wide spectrum of patients. Those with T serosanguineous drainage or a stable

sternum and superficial infection without systemic reaction are considered less serious. Considerably more serious are patients with a draining, unstable sternum, retrosternal space infections, or a systemic reaction unresponsive to local incision and imgation.2

Host factors contributing to increased infection risk include:

age, very old or very young, obesity, malnutrition, presence of preoperative infection, use of steroids, and diabetes mellitus.3

Other contributory variables are more than one surgery in a single admission and surgery lasting longer than six hours! Some studies suggest an increased incidence of mediastinitis when using an internal mammary artery graft? Additional factors associated with sternal wound complica- tions in patients undergoing median sternotomy include:

faulty closure of the sternum, tracheostomy, prolonged ventilatory assistance,

respiratory infection, septicemia, low cardiac output, closed chest massage, and reoperation for bleeding!

Prevention Measures

reoperative preventive measures for decreas- ing infection risks include an awareness of P associated host factors and a commitment

to optimize the patient's physiological status before surgery.

Adequate skin preparation is another important measure. Bathing with hexachlorophene soap the day before surgery is thought to be important.' In our OR, 99% alcohol is used to degrease the skin followed by undiluted 10% povidone-iodine solution to paint the skin. Hair is removed with either a depilatory cream or a razor. Because razors may injure the skin, shaving is done the day of surgery to lessen the infection risk?

Prophylactic antibiotic therapy with either cefazolin or vancomycin is started in the holding area and continued for 48 hours after the surgery. The therapy timing is important to ensure therapeutic levels during surgery while not allowing bacterial resistance to develop? Studies evaluating the effectiveness of prophylactic antibiotic therapy have yielded differing results."J However, most institutions use it. Limiting the patient's preoperative stay to 48 hours or less is also suggested to decrease infection risks1'

Because most infections, endogenous or exogenous, apparently result from operating room contaminants, the surgical team plays an important role in preventing sternal wound infections.l2 Basic preventative measures are scrubbing and wearing proper OR attire. The draping procedure creates another barrier. At our institution, a cardiovascular plastic barrier is used with disposable drapes to prevent bacterial and fluid penetration.

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Surgeons and OR nurses should regard the leg as a potentially contaminated

area harboring pathogenic organisms.

Reducing the number of people and activities in the OR helps limit the airborne contaminants. The OR nurses can help by ensuring that all those in surgery, either assisting or observing, follow the principles of sterility.

To prevent contamination of the sternal wound from the leg, surgeons and OR nurses should regard the leg as a potentially contaminated area harboring pathogenic organisms. Organisms isolated from sternal wound infections are sometimes found in leg woundsL3 This suggests that bacteria may be transmitted from the leg to the sternal wound in the course of saphenous vein harvesting and coronary bypass. To prevent contamination, the scrub nurse should make certain that the same instruments are not used in the leg and in the chest and that the harvest site is covered with a sterile towel until closing. Additionally, the surgeon and nurse should always change gloves when moving from the leg to the chest.

Surgical technique is another important preventative measure. This includes using a mechanically stable sternal closure. Careful approximation of the sternal periosteum and sternalis muscle is critical to avoid postoperative sternal separation. When possible, the surgeon should avoid using bone wax, a foreign substance.14 Additionally, the sternal saw should be routinely dismantled and cleaned before sterilization because bone chips may adhere to the saw blade. One author reported that sternal wound infections decreased after instituting the pra~tice.'~

Postoperative Wound Care

he nurse checks the postoperative patient frequently for signs of sternal wound T complications, particularly in high-risk

individuals. Mediastinitis is usually seen within four to 30 days postoperatively.16 Typically, infection signs and symptoms include pyrexia,

tachycardia, tachypnea, and leukocytosis. Erythema and purulent drainage at the operative site are other infection signs. A wound should be considered infected if purulent material drains from it, regardless of a positive ~u1ture.l~ A body temperature of 102 OF (38.9 "C) is common in the first 48 hours following cardiac surgery. But if it persists after 72 hours, other sources such as wound infection should be investigated.

Sternal wound infection may be accompanied by sternal instability and dehiscence. Sternal instability often precedes infection as bacterial contamination can occur through disrupted skin edges. The patient may have complaints of severe or unique incisional pain and of a rubbing or clicking sensation. The sudden appearance of serous or cloudy fluid often indmtes separation of the wound's deepest layer in the sternum. But the most reliable sign is palpable separation of the sternal edges when the patient coughs.1*

Instituting prompt treatment once signs of sternal wound complications are discovered is important. The most common infectious organism is Staphylococcus aureus. S aureus or other gram- positive infections are usually related to intraop- erative contamination, while gram-negative organisms such as Escherichia coli and the bacteria families of Pseudornonas, Klebsiella, or Enterobacter are usually the infectious agents in the postoperative period. Sources of these may be hemodynamic monitoring and respiratory equipment.19

Incision and drainage of the subcutaneous tissue and open irrigation with antibiotic or antiseptic solution is recommended for patients who have serosanguinous drainage without positive wound cultures or wound infections without a systemic reaction. Superficial wound infections accompan- ied by a systemic reaction may be treated by this technique if the white blood count and temperature are carefully monitored. It may also be used for patients unable to undergo general anesthesia

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Irrigating with povidone-iodine is less costly than antibiotics and is effective

against bacteria and fungi.

required for sternal debridement.2O Local wound irrigation is accompanied by application of sterile dressings soaked in a povidone-iodine or Dakin’s solution (0.25% chloramine-T) and changed three to four times per day. Sterile gloves should be used along with handwashing by all personnel performing postoperative wound care.

Patients who develop sternal dehiscence, a draining unstable sternum or wound infection with evidence of communication with the mediastinum, require more aggressive treatment. A mediastinum debridement is done in the OR with placement of drainage tubes. The mediastinum is irrigated continuously with either an antibiotic or antiseptic solution using a closed drainage system. Povidone- iodine solution (10%) has several advantages as an irrigant. It is less costly than irrigating with antibiotics and is effective against bacteria and fungi.21 The solution is diluted in normal saline (50 mL to 1 L) and given at a rate of about 3 L per day. The irrigation is continued along with systemic antibiotic therapy for one to two weeks (or longer), and wound cultures are monitored until negative. This method of treatment is also used for patients who have a superficial infection not responsive to local irrigation and dressing changes.22

Many nursing diagnoses are associated with the primary problems, particularly in cases of more severe sternal complications. Disturbances in body image, nutrition, pain, and mobility can occur. Performing respiratory exercises in the postoper- ative cardiac patient is important in restoring and maintaining adequate ventilation. However, rigorous physical therapy and coughing might be contraindicated in patients with sternal instability. Mobility may be impaired in patients afraid of increasing the size of the wound or who have continuous irrigation using a closed drainage system.

Skin integrity may be disrupted because of frequent dressing changes and drainage leaking

onto the surrounding area. Hypoallergenic tape can help to alleviate minor skin reactions. Semipermanent adhesive material, like that used to anchor ostomy bags, can help reduce irritation from continually removing and reapplying surgical tape.

In the case of M.T., disturbances in body image and pain were significant. M.T. refused to look at her chest and complained of pain and nausea when dressing changes were done. She continually asked the nursing staff to describe the wound. When she was asked to draw a picture of it, she depicted it with jagged edges rather than the smooth lines of a surgical incision. She was reluctant to get out of bed and perform spirometry exercises because of pain and the fear of splitting open her chest. 0

Notes 1. Cyrus Serry et al, “Sternal wound complications,”

Journal of Thoracic and Cardiovascular Surgery 80 (December 1980) 861-867.

2. Ibd 861-862. 3. Bryan P Simmons, “CDC guidelines for prevention

of surgical wound infections,” AORN Journal 37 (February 1983) 556-576.

4. Elisheva Simchen et al, “Risk factors for post- operative wound infection in cardiac surgery patients,” Infection Control 4 (April 1983) 215-220.

5. Michael G Sam, Vincent L Gott, Timothy R Townsend, “Mediastinal infection after cardiac surgery,” Annab of Thorack Surgery 38 (October 1984) 415- 423.

6. Richard M Engelmann et al, “Mediastinitis following open-heart surgery,” Archives of Surgery 107 (November 1973) 776; Serry, Bleck, Javid, “Sternal wound complications,” 864.

7. Ronald Lee Nichols, “Techniques known to prevent post-operative wound infection,” Infection Confro13 (March 1982) 34-37; Sam, Gott, Townsend, “Mediastinal infection after cardiac surgery,” 420 Bryan P Simmons, “Guidelines for prevention of surgical wound infections,” Infection Control 3 (March-April 1982) 187-196; R D Sutherland, H E Martinez, W A Guynes, LaWayne Miller, “Postoperative chest wound infections in patients requiring coronary bypass,” Journal of Thoracic and Cardiovascular Surgery 73

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(June 1977) 944. 8. Simmons, “CDC guidelines on infection control,”

9. Nichols, “Techniques known to prevent post- operative wound infection,” 34; Mervyn Shapiro, “Perioperative prophylactic use of antibiotics in surgery: Principles and practice,” Infection Control 3 (January 1982) 38. 10. Ignatius W Fong, Clare B Baker, David C McKee,

“The value of prophylactic antibiotics in aortacoronary bypass operations,” Journal of Thoracic and Cardio- vascular Surgery 78 (December 1979) 908-913; Sutherland, Martinez, Guynes, Miller, “Postoperative chest wound infection in patients requiring coronary bypass,” 944.

1 1. Inge Gurevich, “Infectious complications after open heart surgery,” Heart and Lung 13 (September 1984) 472-479; Nichols, “Techniques known to prevent post- operative wound infection,” 34-37; Simmons “Guide- lines for prevention of surgical wound infections,” 188- 196. 12. Simmons “Guidelines for prevention of surgical

wound infections,” 190. 13. F C Wells, S W B Newsom, Christine Rowlands,

“Wound infections in cardiothoracic surgery,” Lancet 1 (May 1983) 1209-1210. 14. Sarr, Gott, Townsend, “Mediastinal infection after

cardiac surgery,” 420. 15. Allen B Kaiser, “Effective and creative surveillance

and reporting of surgical wound infection,” Znfection Control 3 (January 1982) 41-43.

16. Sarr, Gott, Townsend, “Mediastinal infection after cardiac surgery,” 418.

17. Simmons, “Guidelines for prevention of surgical wound infections,” 189.

18. William S Stoney et al, “Median sternotomy dehiscence,” A n d of Thoracic Surgery 26 (November 1978) 423. 19. Sarr, Gott, Townsend, “Mediastinal infection after

cardiac surgery,” 415-423. 20. Seny, Bleck, Javid, “Sternal wound complica-

tions,” 865. 21. Geri Bude Sheim Neuberger, Joann Bell Reckling,

“A new look at wound care,” Nursing 15 (February 1985) 34-4 1. 22. Serry, Bleck, Javid, “Sternal wound complica-

tions,” 866.

189-196.

Coenzyme Performs Well in Cadiomyopathy Tests If results of recent tests are any indication, help may be on the way for patients with advanced cardiomyopathy. Coenzyme QI0, a vitamin K- like substance, produced significant improve- ments in heart functions of patients with advanced cardiomyopathy, according to a report in the Aug 12 Medical World News.

Per H. Langsjoen, MD, a cardiologist at Scott and White Clinic in Temple, Tex, conducted the double-blind, cross-over tests on 19 patients given daily oral dosages for 12 weeks. Each patient, who had class I11 or IV cardiomyopathy, first underwent cardiac function tests. Then after 12 weeks of treatment with either the coenzyme or a placebo, the patients were reevaluated and switched to the alternate treatments. After a second 12-week course, they were tested again. Results showed stroke volume increased signifi-

cantly compared with measurements made at baseline and after placebo. Increased strength and reduced shortness of breath were also noted. No adverse reactions were seen.

Although his findings corroborated the find- ings of several previous studies, some cardiolo- gists were skeptical. Heart transplants are still con- sidered the most effective treatment for cardiom y opathy .

Mosquitoes Not AIDS Carriers There is no evidence to support the theory that AIDS is transmitted by mosquitoes, according to D. Peter Drotman, MD, MPH, Centers for Dis- ease Control, Atlanta, writing in response to a question in the Aug 23 issue of the Journal of the American Medical Assocation.

“The bulk of evidence argues against routes of transmission other than sexual or blood related,” said Dr Drotman. Insect-borne transmission has not been implicated in any country, and the rela- tive absence of reported disease in preadolescent children argues against it, according to Dr Drotman.

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