The prevention of infection in appendicectomy wounds

Intra-operative wound irrigation to reduce surgical site infections after abdominal surgery: a systematic review and meta-analysis

PURPOSE

Surgical site infection (SSI) remains to be one of the most frequent infectious complications following abdominal surgery. Prophylactic intra-operative wound irrigation (IOWI) before skin closure has been proposed to reduce bacterial wound contamination and the risk of SSI. However, current recommendations on its use are conflicting especially concerning antibiotic and antiseptic solutions because of their potential tissue toxicity and enhancement of bacterial drug resistances.

METHODS

To analyze the existing evidence for the effect of IOWI with topical antibiotics, povidone-iodine (PVP-I) solutions or saline on the incidence of SSI following open abdominal surgery, a systematic review and meta-analysis of randomized controlled trials (RCTs) was carried out according to the recommendations of the Cochrane Collaboration.

RESULTS

Forty-one RCTs reporting primary data of over 9000 patients were analyzed. Meta-analysis on the effect of IOWI with any solution compared to no irrigation revealed a significant benefit in the reduction of SSI rates (OR = 0.54, 95 % confidence Interval (CI) [0.42; 0.69], p < 0.0001). Subgroup analyses showed that this effect was strongest in colorectal surgery and that IOWI with antibiotic solutions had a stronger effect than irrigation with PVP-I or saline. However, all of the included trials were at considerable risk of bias according to the quality assessment.

CONCLUSION

These results suggest that IOWI before skin closure represents a pragmatic and economical approach to reduce postoperative SSI after abdominal surgery and that antibiotic solutions seem to be more effective than PVP-I solutions or simple saline, and it might be worth to re-evaluate their use for specific indications.

Irrigation of abdomen with imipenem solution decreases surgical site infections in patients with perforated appendicitis: a randomized clinical trial

Background:

Perforated appendicitis is one of the most common causes of acute abdomen requiring emergent surgery for immediate appendectomy and peritoneal cavity irrigation; however, the efficacy of irrigation with antibiotic solutions is controversial.

Objectives:

The aim of this study was to assess the efficacy of imipenem solution irrigation on post-operative surgical site infections (SSIs), hospital length of stay, and hospital costs. We hypothesized that there would be lower rate of SSIs, a shorter hospital stay, and lower hospital cost in patients with perforated appendicitis who received peritoneal cavity irrigation with imipenem solution in comparison to their counterparts who received irrigation with normal saline.

Patients and Methods:

In this randomized single-blind parallel-group clinical trial, we enrolled 90 patients with perforated appendicitis with 12-50 years of age and randomly allocated them into experimental group (n = 45) and control group (n = 45). The control group received peritoneal irrigation with normal saline (0.9%) and experimental group underwent peritoneal irrigation with imipenem solution (1 mg/mL). All surgical procedures were performed in Imam Reza Hospital of Kermanshah University of Medical Sciences. The study primary outcome was surgical site infections (including wound infection and abdominal abscess) and the secondary outcomes were length of hospital stay and hospital cost. Chi-squared and t-tests were used to analyze the study data.

Results:

Imipenem solution irrigation was associated with significant clinical improvement at one-month follow-up. The experimental group presented with significantly lower rate of SSIs and shorter length of hospital stay. The experimental group had lower rate of SSIs compared to the control group (4.4% vs. 22.2%, respectively) (p= 0.013). The duration of hospital stay was nearly one day longer in control group (5.84 ± 2.58 days) vs. experimental group (4.91 ± 1.29 days) (P = 0.034), and hospital costs were $50 lower in experimental group ($500 ± $292) vs. control group ($450 ± $170) (P = 0.281).

Conclusions:

The study findings revealed that peritoneal lavage with imipenem solution (1 mg/mL) decreases the rate of post-operative SSIs in patients with perforated appendicitis in comparison to patients irrigated with normal saline alone. These patients also had shorter hospital stay, and lower hospital costs.

Leg wound infections associated with coronary revascularization

BACKGROUND

Wound infections after saphenous vein harvest for coronary revascularization are common but they are infrequently examined. The aim of the present study was to investigate the risk factors for infection and the possible beneficial effects of saline lavage.

METHODS

From April 1996 to July 1996, 152 consecutive patients who underwent saphenous vein harvest for coronary artery bypass graft were recruited. Factors that may influence infection rates were analysed.

RESULTS

A total of 22 of the 125 (18%) patients included in the present study developed a wound infection. The length of the wound was the only variable found to have a statistically significant association with wound infection. In the analysis of patients with multiple leg wounds, the development of infection correlated with the absence of mechanical wash-out.

CONCLUSION

The use of saline lavage may prevent wound infections by diluting the bacterial population prior to closure. The use of antiseptic or antibiotic lavage may offer an additional benefit.

Topical ampicillin for prophylaxis against wound infection in acute appendicitis

A total of 249 patients, undergoing appendectomy for acute appendicitis, were prospectively randomized into two groups. Group I, comprising 132 patients, received sterile normal saline irrigation to the surgical wound at closure. Alternatively, Group II included 117 patients, who received intraoperative topical ampicillin irrigation of the wound. Both groups were comparable with regard to age, sex, duration of symptoms, and severity of appendicitis. All patients additionally received preoperative systemic gentamicin and Flagyl. Wound infection occurred in 5.3% of Group I compared to only 0.9% of Group II (P<0.05). The reduction in infection rate was significant (P<0.05) in histologically proven appendicitis. We conclude that the addition of intraoperative topical ampicillin to systemic gentamicin and Flagyl augments prophylaxis against wound infection in acute appendicitis.

Preventing wound infection after appendicectomy: a review

An exponential increase in the number of published prospective studies reflects both a continuing interest in, and a lack of consensus on, the optimal prophylaxis of wound sepsis after appendicectomy. Review of the literature over the last 25 years leads us to emphasize both the importance of adequate study size and of stratification of the severity of the sepsis found at operation. For critical comparison of prophylactic regimens the high percentage of wound infections disclosed after discharge from hospital must be taken into account. Antibiotics reduce the frequency of wound sepsis and although low wound sepsis rates have been reported with systemic antibiotics active against only anaerobes, the cumulative evidence favours a spectrum of antibacterial activity against both aerobic and anaerobic organisms. Topical antiseptics have no significant effect but topical antibiotics are beneficial. Wide variations in outcome for similar antibiotic regimens reflect the importance of technical factors in determining the frequency of wound sepsis.

A trial of povidone-iodine in the prevention of infection in sutured lacerations

A prospective, randomized study of 500 consecutive emergency department patients with traumatic lacerations requiring sutures was performed comparing use of topical 1% povidone-iodine (Betadine) and scrubbing with wound management by irrigation with normal saline without scrubbing. A 60-second wound irrigation and scrub with a 1% povidone-iodine solution was the only difference in treatment between the two groups. Data relating to risk factors such as age; degree of contamination; type of closure; ethanol intoxication; mechanism of injury; and bone, joint, or tendon involvement were analyzed. Wounds were classified as clean, infected, or purulent at follow-up examination. One hundred five patients were lost to follow-up. Of the 395 remaining patients, 122 were contacted by phone and were classified based on their description of the wound; 273 were classified at reexamination in the ED. Of 201 povidone-iodine group wounds, 11 became infected; two of them (5.4%) were purulent. Of 194 control wounds, 30 became infected, of which 12 (15.46%) were purulent (P less than .01). These data suggest that use of a topical 1% povidone-iodine solution in traumatic lacerations prior to suturing reduces the incidence of wound infections.

Antibiotic irrigations. A plea for controlled clinical trials

Although the medical literature describes the perioperative use of antibiotic irrigations in abdominal, pelvic, orthopedic and vascular surgery, the lack of well-designed and executed, controlled clinical studies often precludes a definitive assessment of the value of this technique. Future randomized, double-blind, controlled clinical trials are required to establish its merit. In this age of cost consciousness, lavages with antibiotic solutions cannot at present be regarded as conventional medical therapy.

Prophylaxis of infection after appendicectomy: a survey of current surgical practice

Two hundred and eighty questionnaires were sent to junior surgical staff throughout England inquiring about their use of systemic antibiotic prophylaxis, topical antibacterial agents, and surgical drainage in appendicectomy. One hundred and seventy-five (63%) replies were received from 81 of the 87 hospitals included in the survey. Prophylactic systemic antibiotics were used by 78 surgeons (46%) when operating on a normal appendix but by 168 (99%) when the organ had perforated. Most surgeons started antibiotics before operation, but proportionately fewer did so when the appendix was gangrenous or perforated. Patients with severe contamination tended to receive longer courses of antibiotics, although the duration of administration varied considerably. Metronidazole was included in over 95% of all the prophylactic regimens and was often combined with other drugs when the appendix was gangrenous and perforated. Topical antibacterial agents were applied to the wound routinely by only 45 surgeons (26%), although 106 (61%) used them sometimes. Povidone-iodine was the agent most commonly used. Only 98 surgeons (56%) ever drained appendicectomy wounds, while 135 (77%) sometimes drained the peritoneal cavity. Evidence suggests that present methods of giving systemic antibiotic prophylaxis should continue, but that topical agents and surgical drainage are perhaps unnecessary when surgeons are confident of the efficacy of the systemic treatment used.

The prevention of post-appendicectomy sepsis by metronidazole and cefazolin: a controlled double blind trial

A double blind, randomized, controlled trial was carried out at two hospitals to try the effect of metronidazole, which is effective against most anaerobes, and cefazolin, which is effective against many aerobic organisms, singly and in combination, on the incidence of wound sepsis following appendicectomy. Patients were placed at random into one of four groups; to receive metronidazole and placebo, cefazolin and placebo, metronidazole and cefazolin, or double placebo. Patients with generalized peritonitis were excluded for ethical reasons. Treatment was started before operation and continued eight-hourly for twenty-four hours. All patients in the trial were followed up at about two weeks after discharge from hospital and their wounds inspected. Two hundred and seventy-one patients were assessed. Sepsis rates at the two hospitals were similar. On the untreated controls, 30% discharged pus from their wounds, and in the groups receiving one drug only, about 20%. In those receiving both drugs the infection rate was 3%, a highly significant difference from that in the other three groups.

A double-blind trial of a single intravenous dose of metronidazole as prophylaxis against wound infection following appendicectomy

One hundred patients undergoing appendicectomy through a right iliac fossa incision were randomized to receive normal saline or 500 mg metronidazole as an intravenous infusion during the operation. One patient in the saline group developed an erythematous rash. There were 13 wound infections (as defined by the discharge of pus), 12 (out of 51) in the saline group and 1 (out of 49) in the metronidazole group. Bacteroides spp. were frequently cultured from the lumen of removed appendices and from pus obtained from infected wounds. This work supports the value of metronidazole but suggests that a single-dose regimen is adequate for prophylaxis.

Peritoneal lavage in appendicular peritonitis

Peritoneal lavage resulted in a significant reduction in the duration of hospital stay in a retrospective series of 189 children with peritonitis secondary to perforation of the appendix. Antibiotic peritoneal lavage also resulted in a significant reduction in the number of children with septic and adhesive complications compared with antiseptic lavage and no lavage, mainly as a result of fewer wound infections. The overall incidence of residual intraperitoneal infection was low, and although differences in this respect were not significant, none of the children treated with antibiotic peritoneal lavage required reoperation for intraperitoneal sepsis.

Improving cholecystectomy

Bacteriologic study of bile in 100 patients undergoing cholecystectomy for various manifestations of choletithiasis yielded 36 per cent positive cultures, with greater frequency in older individuals and those with acute cholecystitis and common duct stone; these results are comparable to those in previous studies and reaffirm the septicity of the bile. Incidence of wound infection, averanging 10 per cent in published series of cholecystectomies, was 0.5 per cent in 200 patients in whom a water-impermeable wound drape was sewn to the peritoneum to prevent contamination by potentially infected bile. This result, in patients with an infectious risk comparable to that in other series, establishes the value of meticulous wound isolation in preventing wound infection.

Prophylactic lincomycin in the prevention of wound infection following appendicectomy: a double blind study

The prophylactic use of a single dose of lincomycin in 100 patients undergoing appendicectomy reduced the incidence of postoperative wound infection from 17 to 6 per cent compared with a similar group of control patients. There was no correlation with the histological finding in the appendix, but patients with perforated appendicitis were excluded from the study. Bacteriological examination of the appendix area before surgery showed that Bacteroides fragilis and Escherichia coli were the organisms most frequently isolated. The majority of wound infections were due to B. fragilis, either alone or in association with aerobic organisms, but infection due to E. coli and Staphylococcus aureus also occurred. Systemic antibiotic therapy can successfully reduce the complications following appendicectomy but it is necessary to use a compound with activity against anaerobic organisms.

Metronidazole in prevention and treatment of bacteroides infections after appendicectomy

The frequency of non-clostridial anaerobic infection was studied in 95 patients who had undergone acute appendicectomy: 49 received prophylactic metronidazole and 46 received placebo. Anaerobic infection did not develop in any of the metronidazole-treated patients, but infections did develop in nine (19%) of the 46 controls. Metronidazole is conveniently administered by suppository to patients who cannot take oral drugs. Five patients with intra-abdominal infections caused by non-clostridial anaerobes were successfully treated with metronidazole.

Controlled trial of prophylactic antibiotics in minor wounds requiring suture

Minor wounds presenting in the accident department requiring suture were randomly allocated to one of three treatment groups: an intramuscular injection of 1-25 megaunits of penicillin as a long-acting depot preparation, local wound irrigation with 100mg of tetracycline in solution, or no antibiotics. All wounds had a standard surgical toilet and were closed under aseptic conditions. Wound infections were noted five to seven days after suture, and in the two groups receiving antibiotics 23% of the wounds were infected whilst in the control group the frequency was 7%. The wisdom of using routine antibiotic prophylaxis in minor wounds is questioned.

Wound infections due to Bacteroides fragilis following intestinal surgery

Ninety-six wound infections due to Bacteroides fragilis occurring after intestinal surgery are described. Most infections followed appendicectomy or colectomy for diverticulitis. B. fragilis was isolated in pure growth from 47 per cent of infections, and in mixed culture the other common bacteria were Klebsiella spp., Escherichia coli and Enterobacter spp. Fifty-three per cent of the infections responded rapidly to either non-specific measures or antibiotic therapy, but 47 per cent of patients developed complications, usually abscess formation. The successful isolation of bacteroides from clinical material requires special precautions. The specimen for bacteriological examination must be sent to the laboratory in a transport medium which maintains an anaerobic environment and the culture techniques must include a selective agar for the isolation of anaerobic bacteria. The role of antibiotic therapy in preventing postoperative wound infection after intestinal surgery is discussed. Bacteroides has an unusualy pattern of antibiotic susceptibility and it is essential that an effective antibiotic such as lincomycin is included in the treatment of infection originating from the intestinal tract.

Bacterial flora of the appendix fossa in appendicitis and postoperative wound infection

Bacteria were isolated from 153 (47.5%) swabs of the appendix fossa in 322 patients undergoing appendicectomy. The commonest organism was Bacteroides species found in 78% of specimens. Other Gram-negative bacilli such as Klebsiella, or Enterobacter, and Esch. coli were present in 29 and 27% respectively. Gram-positive cocci were less frequently isolated.A positive culture was obtained more commonly in perforated appendicitis (79%) than where chronic fibrosis, lymphoid hyperplasia, or acute appendicitis was present or when the appendix was normal. Bacteroides was isolated twice as often in perforated appendicitis. The incidence of wound infection was 19% and varied according to the state of the appendix, being 63% in perforated appendicitis and 9.5% where lymphoid hyperplasia was present. Bacteroides was isolated from over 90% of the wound infections. In the patients with perforated appendicitis where effective chemotherapy was given the incidence of wound infection was 15% whereas in untreated or inappropriately treated patients it was over 50%. The isolation of bacteroides requires special precautions to be taken both in the collection of the specimen and laboratory culture. It is important that the chemotherapy of postappendicectomy infections include an antibiotic active against bacteroides.

Topical ampicillin in the prevention of wound infection after appendicectomy

The effect of topical ampicillin on the rate of wound infection after emergency appendicectomy was studied in a prospective controlled trial of 200 patients. Sixteen per cent of patients in the control group developed a wound injection compared with 3 per cent of those receiving ampicillin powder in the wound (P&lt;0·01). When patients with peritonitis were considered, 64 per cent of the 14 patients in the control group developed a wound infection compared with 13 per cent of the 15 patients in the ampicillin group.

Patients in the control group were discharged from hospital in a mean of 8·7 days postoperatively compared with 6·4 days in the ampicillin group (P&lt;0·05).

The reduction of surgical wound infections by topical cephaloridine: a controlled clinical trial

Four hundred and one consecutive patients having surgical operations were studied. Of these, 188 cases selected at random had 1 g of cephaloridine in 2 ml of water instilled into the wound before closure, the remainder being controls. In the group receiving cephaloridine 9 per cent of the wounds became infected and in the control group 22.1 per cent. The difference could have arisen by chance less than once in a thousand times.

The reduction of surgical wound infections by prophylactic parenteral cephaloridine. A controlled clinical trial

In a series of 762 general surgical wounds 376 were selected at random to receive three parenteral doses of cephaloridine and 386 remained as untreated controls. In all types of operation, with the exception of wounds in the lower extremities associated with arterial surgery, the rate of wound infection was lowered by the prophylactic use of cephaloridine. The results were statistically significant for total wounds, clean wounds, total contaminated wounds, and contaminated wounds other than in colorectal surgery. We therefore recommend the routine use of three doses of cephaloridine.