Reduction of Infection Rates in Abdominal Incisions By Delayed Wound Closure Techniques Edward D. Verrier, MD, San Francisco, California K. Jan Bossart, MD, San Francisco, California F. William Heer, MD, San Francisco, California

Reducing the risk of wound infection by delayed closure of skin and subcutaneous tissue of contaminated and infected wounds has been practiced for 200 years [I]. More recently, delayed primary closure has evolved as the preferred method. Contemporary application of this method in the United States began in 1919, when H. H. Hepburn [2] reported a 50 per cent reduction in the wound infection rate with delayed primary closure in 104 contaminated extremity wounds. Since 1940 numerous reports have advocated delayed closure techniques in contaminated abdominal operations to reduce the incidence of wound infection [3-121. Increased understanding of the physiology of healing in both infected and noninfected wounds has supported this moda1it.y of wound management [13-171. In private surgical practice, the use of delayed closure techniques is variable, individualized, and rarely reported [8]. P ossible reasons for this observation are: (1) delayed primary closure by suturing frequently requires additional anesthesia, discomfort, and expense for the patient; (2) most evaluations of these techniques originate from military [2,18], civilian trauma [IO], or university centers [3-7,1012,191; and (3) numerous recent reports on the physiology of wound healing emphasize adjunctive measures other than delayed primary closure. These measures include the use of antibiotics [20,21], supplemental oxygen therapy [22], vitamins [23], insulin therapy in diabetics [24], and parenteral nutrition [25,26] to reduce wound infection. This study reports the experience with delayed primary and secondary closure techniques in a private teaching practice. The method used is simple From the Department of Surgery, University of California School of Medicine and Ralph K. Davies Medical Center, San Francisco, California. Reprint requests should be addressed to F. William Heer, MD, Department of Surgery, Ralph K. Davies Medical Center, Castro and Duboce, San Francisco, California 94114. Presented at the 50th Annual Meeting of the Pacific Coast Surgical Society, Yosemite National Park, California, February 19-22, 1979.

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and inexpensive, does not require anesthesia, and is appropriate for use in infected, contaminated, and selected clean-contaminated incisions. Healing was by secondary intention when infection was observed in any wound or delayed primary closure was contraindicated for other reasons. The risk factors which favor the selection of delayed primary closure in clean-contaminated wounds are emphasized. Material and Methods We evaluated 575 consecutive patients undergoing abdominal operations between 1975 and 1978. The degree of

contamination time of wound wounds were contaminated,

and infection risk was determined at the closure by a single surgeon (FWH), and all classified as clean, clean-contaminated, or infected, as defined in the Manual for Control of Infections in Surgical Patients [27] (Table I). Preoperative skin preparation included shaving and a 10 minute Betadine@ detergent scrub followed by the application of sterile Betadine solution, which was removed with 95 per cent alcohol. Draping was done with sterile linen towels, plastic adherent, and paper drapes. The skin was incised with the scalpel while the subcutaneous and deeper layers were opened with the electrocautery unit. Hemostasis was obtained with fine silk ligatures and the cautery. Closure techniques varied. Layered interrupted silk sutures were used for inguinal hernia repairs. In major abdominal incisions the peritoneum was closed with running chromic catgut sutures reinforced with interrupted silk. The retention sutures employed in all of these incisions were either (1) through-and-through no. 2 nylon sutures with interrupted silk sutures for fascial apposition, or (2) near-far-far-near 0 prolene or no. 28 stainless steel internal fascial sutures. Saline wound irrigation was used in clean-contaminated wounds and 0.5 per cent kanamycin was reserved for use in severely contaminated or infected wounds before closure. Bacterial smears of available exudate and body fluids were made to aid in the assessment of wound contamination risk and antibiotic selection at the time of surgery.

The American

Journal

of Surgery

Reduction

TABLE I

Operative Wound Classification According to Contamination-Infection

Operative Wound Class

Viscus Entry

Breaks in Technique

Spillage

of Infection

in Abdominal

Incisions

Risk Categories [27]

Trauma

Miscellaneous

1.

Clean

None

None

None

None

No Inflammation

2.

Clean contaminated

A.

Minimal

Minimal

None

Nonperforated appendicitis without cloudy fluid

3.

Contaminated

Gross gastrointestinal; any colon

Major

Fresh traumatic wound

4.

Infected

Prepared oropharynx and vagina B. Noninfected urinary or biliary tract Genitourinary or biliary with infected urine or bile Perforated viscus encountered

-

Cultures were taken for aerobic and anaerobic bacterial identification in infected and contaminated cases, but only when increased suspicion of contamination existed in clean and clean-contaminated operations. All wound infections were cultured in the same manner. Primary closure was performed with Steri-Strips@ (3M Company), supplemented with fine monofilament plastic cutaneous sutures where precise apposition could not be obtained with Steri-Strips. Wounds to be closed by delayed primary closure were left open with loose, fine-mesh gauze impregnated with petrolatum containing beeswax and 3.0 per cent bismuth tribromphenate (Xeroforme, Chesebrough Ponds) inserted between skin and subcutaneous margins down to the level of fascial closure. Excess petrolatum was removed from the gauze before insertion to avoid a grease seal that would hamper the desired wound drainage. Xeroform gauze was selected on the basis of availability and the theoretical bacteriostatic benefits of the phenolated bismuth [28]. Each wound was left undisturbed until the 5th postoperative day when the Xeroform gauze was removed and delayed primary closure with Steri-Strips was done on the ward without anesthesia. Normally a scant to moderate serous fluid drainage and scant fibrinous exudate were observed at this time. When this appeared excessive, local wound care with wet-to-dry saline compresses was initiated. When possible, a later delayed primary closure was performed. The wound was allowed to heal by secondary intention in three circumstances: (1) when frank wound infection was present, (2) when closure could not be technically accomplished with Steri-Strips, and (3) when inspection suggested that the risk of infection was too high to warrant attempted delayed primary closure. Wounds allowed to heal by secondary intention were treated with wet-to-dry dressings using fine-mesh gauze, saline, peroxide or Dakin’s solution, and mechanical debridement as indicated by a particular wound’s local condition. No effort to close, re-excise, or approximate the skin or subcutaneous tissue was made, and all layers of the wound were allowed to heal by deep granulation and epithelial bridging.

Volume 138, July 1979

Dirty, devitalized tissue, foreign body, or delay in treatment

Transected clean tissue for surgical .drainage of abscesses

Wound infection was defined as any wound exhibiting cellulitis with erythema, swelling, or increased tenderness, suppuration or liquefaction of tissue, abscess, sept.ic necrosis of tissues, or septic thrombophlebibis in the vicinity of the local wound [27]. A wound infection was classified as major if more than a part of the wound, more than a superficial layer of the wound, or regional or systemic findings were noted. Minor wound infections were focal, noninvasive, and superficial. A retrospective protocol to review all cases was devised to assess the subsequent wound infection rates and the factors appearing to influence the development of wound infection. The risk factors evaluated were (1) age, (2) sex, (3) wound contamination classification 1291, (4) method of closure (primary, delayed primary, secondary), (5) surgical diagnosis, (6) anatomic region of operation, (7) location of incision, (8) suture material, (9) use of prophylactic or therapeutic antibiotics, (10) timing and route of antibiotic administration, (11) pertinent cultures, (12) estimated blood loss, (13) the use of low-dose heparin therapy, and (14) the presence or absence of associated conditions. The associated conditions included (1) diabetes mellitus, (2) obesity, (3) clinical malnutrition, (4) chronic steroid use, (5) atherosclerotic cardiovascular disease, (6) coexistent malignancy other than that for which the operation was being performed, and (7) a miscellaneous category. lneluded in this last category were 30 infrequently observed, potentially adverse conditions such as chronic obstructive pulmonary disease, chronic renal disease, collagen vascular disease, pancreatitis, and reincision through a recently incised wound. Patients were assigned the dominant associated condition if multiple conditions were present. The relation between each of the above variables and the development of postoperative wound infection was studied for statistical significance by chi square analysis. The Yates correction was used in all determinations. Included in the 575 cases were 322 males and 253 females with a mean age of 58.4 years. Two subdivisions were used: the first subgrouping by degree of contaminat.ion risk included 196 clean, 219 clean-contaminated, 104 contaminated, and 56 infected operations; the second subgrouping

23

Verrier et al

by anatomic region included 141 inguinal hernia, 116 biliary tract, 114 colonic, 44 appendiceal, 33 small bowel, 62 gastric, and 65 miscellaneous procedures including such operations as nephrectomy, adrenalectomy, hepatectomy, staging laparotomy, and gynecologic tumor surgery. Results Overall, 31 (5.4 per cent) wound infections were noted among the 575 patients, including 20 (3.5 per cent) major and 11 (1.9 per cent) minor infections. The overall mortality in this series was 3 per cent, but no deaths were attributable to wound infection. Delayed primary closure reduced infection rates compared to primary closure in the following: (1) clean-contaminated, 4.8 per cent to 1.1 per cent; (2) contaminated, 11.1 per cent to 4.8 per cent; and (3) infected, 33.0 per cent to 6.6 per cent. The single wound infection in the clean category with delayed primary closure (one of five) occurred after lysis of adhesions for small bowel obstruction (Table II). Twenty-three infected, 23 contaminated, 5 clean-contaminated, and 5 clean wounds (56 total) were allowed to heal by secondary intention. Of these, 44 healed without infection but 12 (21.4 per cent) became infected (Table II). Other wound complications were assessed. No eviscerations occurred. Fascial dehiscence occurred in 12 patients, all associated with wound infection (39 per cent of the wound infections). By type of closure,

TABLE II

three followed primary closure, one followed delayed primary closure, and eight followed secondary healing. Sixteen incisional hernias have been detected thus far. By type of closure, nine followed primary closure (six were infected), one followed delayed primary closure, and six followed secondary healing (all were infected). Wound hemorrhage requiring suture control occurred four times, twice after primary closure and twice after delayed primary closure, with no consequent infections or hernias. Infection rates according to the anatomic region of operation were as follows: (1) inguinal hernia, 0.7 per cent; (2) biliary tract, 6.0 per cent; (3) colon, 7.4 per cent; (4) appendix, 2.3 per cent; (5) small intestine, 18.2 per cent; (6) gastric, 1.6 per cent; and (7) miscellaneous, 4.3 per cent. The distribution of major and minor wound infections according to the anatomic site of operation is presented in Table III. Inguinal herniorrhaphies (141) are included because these operations constituted the most common clean abdominal operation. By excluding them wound infection rates increase from (1) minor, 1.9 to 2.3 per cent; (2) major, 3.5 to 4.6 per cent; and (3) overall, 5.4 to 6.9 per cent in major abdominal operations. Eighty-seven per cent (379 of 434) of the major abdominal operations were clean-contaminated, contaminated, or infected. Comparisons of all seven anatomic categories revealed no statistically significant elevation in wound

Wound Infection Rates by Type of Closure and Retrospective Contamination Classification

Primary

1.6% (37186)

4.3% (67125)

11.1% (2718)

33.0% (173)

3.6% (12/332)

20.0%

1.1% (1189)

4.8%

(175)

(3/63)

6.6% (2730)

3.7% (71187)

Secondary

0.0% (075)

20.0% (175)

30.0% (7723)

17.0% (4/23)

21.4% (12/56)

Total

2.0% (4/196)

3.7% (8/219)

11.5% (12/104)

12.5% (7/56)

5.4% (31/575)

Delayed Primary Closure

TABLE III

Wound Infection Rates by Anatomic Region of Operation Anatomic Region

Infection Major Minor Total

24

lnauinal H&nia

Biliary Tree

Colon

Appendix

Small Bowel

Stomach

Miscellaneous

Total

0.0% (0) 0.7%

4.3% (5)

4.4% (5)

2.3% (1)

12.1% (4)

1.6% (1)

6.2% (4)

1.7%

3.5%

0.0%

6.1%

0.0%

3.1%

1.9%

(1)

(2)

(4)

(0)

(2)

(0)

(2)

(11)

0.7% (l/141)

6.0% (7/l 16)

7.9% (9/l 14)

2.3% (l/44)

18.2% (6/33)

1.6% (1764)

9.3% (6765)

5.4% (31/575)

3.5% (20)

The American Journal of Surgery

Reduction of Infection in Abdominal

infection rates except for operations involving the small intestine (p

Reduction of infection rates in abdominal incisions by delayed wound closure techniques.

Reduction of Infection Rates in Abdominal Incisions By Delayed Wound Closure Techniques Edward D. Verrier, MD, San Francisco, California K. Jan Bossar...
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