Comparison of one dose versus three doses of prophylactic antibiotics, and the influence of blood transfusion, on infectious complications in acute and elective colorectal surgery

Nomogram to predict postoperative infectious complications after surgery for colorectal cancer: a retrospective cohort study in China

Background

Postoperative infectious complications (ICs) after surgery for colorectal cancer (CRC) increase in-hospital deaths and decrease long-term survival. However, the methodology for IC preoperative and intraoperative risk assessment has not yet been established. We aimed to construct a risk model for IC after surgery for CRC.

Methods

Between January 2016 and June 2020, a total of 593 patients who underwent curative surgery for CRC in Chengdu Second People’s Hospital were enrolled. Preoperative and intraoperative factors were obtained retrospectively. The least absolute shrinkage and selection operator (LASSO) method was used to screen out risk factors for IC. Then, based on the results of LASSO regression analysis, multivariable logistic regression analysis was performed to establish the prediction model. Bootstraps with 300 resamples were performed for internal validation. The performance of the model was evaluated with its calibration and discrimination. The clinical usefulness was assessed by decision curve analysis (DCA).

Results

A total of 95 (16.0%) patients developed ICs after surgery for CRC. Chronic pulmonary diseases, diabetes mellitus, preoperative and/or intraoperative blood transfusion, and longer operation time were independent risk factors for IC. A prediction model was constructed based on these factors. The concordance index (C-index) of the model was 0.761. The calibration curve of the model suggested great agreement. DCA showed that the model was clinically useful.

Conclusion

Several risk factors for IC after surgery for CRC were identified. A prediction model generated by these risk factors may help in identifying patients who may benefit from perioperative optimization.

Perioperative strategies to prevent surgical-site infection

Colon and rectal resections are among the most common surgical procedures performed in the United States. Complication rates of up to 25% have been reported and result in a substantial impact on quality of life and cost of care. Recently, the Surgical Care Improvement Program (SCIP) has promoted guidelines to prevent postoperative and potentially preventable complications. A comprehensive evidenced-based review of these guidelines and other perioperative strategies for practicing colorectal surgeons is the basis of this review.

Antimicrobial prophylaxis for colorectal surgery

BACKGROUND

Research shows that administration of prophylactic antibiotics before colorectal surgery prevents postoperative surgical wound infection. The best antibiotic choice, timing of administration and route of administration remain undetermined.

OBJECTIVES

To establish the effectiveness of antimicrobial prophylaxis for the prevention of surgical wound infection in patients undergoing colorectal surgery. Specifically to determine:1. whether antimicrobial prophylaxis reduces the risk of surgical wound infection;2. the target spectrum of bacteria (aerobic or anaerobic bacteria, or both);3. the best timing and duration of antibiotic administration;4. the most effective route of antibiotic administration (intravenous, oral or both);5. whether any antibiotic is clearly more effective than the currently recommended gold standard specified in published guidelines;6. whether antibiotics should be given before or after surgery.

SEARCH METHODS

For the original review published in 2009 we searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE (Ovid) and EMBASE (Ovid). For the update of this review we rewrote the search strategies and extended the search to cover from 1954 for MEDLINE and 1974 for EMBASE up to 7 January 2013. We searched CENTRAL on the same date (Issue 12, 2012).

SELECTION CRITERIA

Randomised controlled trials of prophylactic antibiotic use in elective and emergency colorectal surgery, with surgical wound infection as an outcome.

DATA COLLECTION AND ANALYSIS

Data were abstracted and reviewed by one review author and checked by another only for the single, dichotomous outcome of surgical wound infection. Quality of evidence was assessed using GRADE methods.

MAIN RESULTS

This updated review includes 260 trials and 68 different antibiotics, including 24 cephalosporins and 43,451 participants. Many studies had multiple variables that separated the two study groups; these could not be compared to other studies that tested one antibiotic and had a single variable separating the two groups. We did not consider the risk of bias arising from attrition and lack of blinding of outcome assessors to affect the results for surgical wound infection.Meta-analyses demonstrated a statistically significant difference in postoperative surgical wound infection when prophylactic antibiotics were compared to placebo/no treatment (risk ratio (RR) 0.34, 95% confidence interval (CI) 0.28 to 0.41, high quality evidence). This translates to a reduction in risk from 39% to 13% with prophylactic antibiotics. The slightly higher risk of wound infection with short-term compared with long-term duration antibiotic did not reach statistical significance (RR 1.10, 95% CI 0.93 to 1.30). Similarly risk of would infection was slightly higher with single-dose antibiotics when compared with multiple dose antibiotics, but the results are compatible with benefit and harm (RR 1.30, 95% CI 0.81 to 2.10). Additional aerobic coverage and additional anaerobic coverage both showed statistically significant improvements in surgical wound infection rates (RR 0.44, 95% CI 0.29 to 0.68 and RR 0.47, 95% CI 0.31 to 0.71, respectively), as did combined oral and intravenous antibiotic prophylaxis when compared to intravenous alone (RR 0.56, 95% CI 0.43 to 0.74), or oral alone (RR 0.56, 95% CI 0.40 to 0.76). Comparison of an antibiotic with anaerobic specificity to one with aerobic specificity showed no significant advantage for either one (RR 0.84, 95% CI 0.30 to 2.36). Two small studies compared giving antibiotics before or after surgery and no significant difference in this timing was found (RR 0.67, 95% CI 0.21 to 2.15). Established gold-standard regimens recommended in major guidelines were no less effective than any other antibiotic choice.

AUTHORS' CONCLUSIONS

This review has found high quality evidence that antibiotics covering aerobic and anaerobic bacteria delivered orally or intravenously (or both) prior to elective colorectal surgery reduce the risk of surgical wound infection. Our review shows that antibiotics delivered within this framework can reduce the risk of postoperative surgical wound infection by as much as 75%. It is not known whether oral antibiotics would still have these effects when the colon is not empty. This aspect of antibiotic dosing has not been tested. Further research is required to establish the optimal timing and duration of dosing, and the frequency of longer-term adverse effects such as Clostridium difficile pseudomembranous colitis.

Antibiotic prophylaxis in colorectal surgery

Nosocomial infections are the most frequent complications observed in surgical patients. In colorectal surgery, the opening of the viscera causes the dissemination into the operative field of microorganisms originating from endogenous sources, increasing the chance of developing postoperative complications. It is reported that without antibiotic prophylaxis, wound infection after colorectal surgery develops in approximately 40% of patients. This percentage decreases to approximately 11% after antibiotic prophylaxis. Specific criteria in the choice of correct antibiotic prophylaxis have to be respected, on the basis of the microorganisms usually found in the surgical site, and on the specific hospital microbiologic epidemiology.

Antimicrobial prophylaxis for colorectal surgery

BACKGROUND

Research shows that administration of prophylactic antibiotics before colorectal surgery prevents postoperative surgical wound infection (SWI). The best antibiotic choice, timing of administration and route of administration remain undetermined.

OBJECTIVES

To establish the effectiveness of antimicrobial prophylaxis for the prevention of SWI in patients undergoing colorectal surgery: specifically to determine, 1 Whether it reduces risk of SWI. 2 The target spectrum/a of bacteria (aerobic and/or anaerobic). 3 The best timing and duration of antibiotic administration. 4 The most effective route of antibiotic administration (intravenous, oral or both). 5 Whether any antibiotic is clearly more effective than the currently recommended gold standard.

SEARCH STRATEGY

CENTRAL, MEDLINE, and EMBASE, were searched from January, 1980 to December, 2007.

SELECTION CRITERIA

Randomised controlled trials of prophylactic antibiotic use in elective and emergency colorectal surgery, with SWI as an outcome.

DATA COLLECTION AND ANALYSIS

Data were abstracted and reviewed by three authors for only the single, dichotomous outcome of SWI.

MAIN RESULTS

The review included 182 trials (30,880 participants), and 50 different antibiotics, including 17 cephalosporins. Many studies had multiple variables that separated the two study groups and could not be compared to other studies that tested one antibiotic and had a single variable separating the two groups. Meta-analyses demonstrated a statistically significant difference in postoperative SWI when prophylactic antibiotics were compared to placebo/no treatment (relative risk (RR) 0.30, 95% confidence intervals (CI) 0.22 to 0.41). No statistically significant differences were shown when comparing short- and long-term duration of prophylaxis (RR 1.06, 95% CI 0.89 to 1.27); or single dose versus multiple dose antibiotics (RR 1.17, 95% CI 0.67 to 2.05). Additional aerobic coverage and additional anaerobic coverage both showed statistically significant improvements in SWI rates (RR 0.41, 95% CI 0.23 to 0.71 and RR 0.55, 95% CI 0.35 to 0.85, respectively); as did combined oral and intravenous antibiotic prophylaxis when compared to intravenous alone (RR 0.55, 95% CI 0.41 to 0.74), or oral alone (RR 0.34, 95% CI 0.13 to 0.87). Established gold standard regimens were no less effective than any other antibiotic choice.

AUTHORS' CONCLUSIONS

Antibiotics covering aerobic and aerobic bacteria should be delivered orally and intravenously prior to colorectal surgery. Antibiotics delivered within this framework will reduce the risk of postoperative SWI by at least 75%. Further research is required to establish the optimal timing and duration of dosing, and frequency of longer-term adverse effects such as Clostridium difficile pseudomembranous colitis.

Mechanical bowel preparation and antibiotic prophylaxis in colorectal surgery: use by and opinions of Spanish surgeons

OBJECTIVE

Antibiotic prophylaxis (AP) and mechanical bowel preparation (MBP) previous to surgery have classically been regarded as important in colorectal surgery. The latter has recently been questioned. We evaluated opinion of Spanish surgeons about the use of these measures.

METHOD

E-mail survey among all members of Spanish Coloproctologic Associations.

RESULTS

Of 413 participants in the survey, 131 (31.7%) responded; 87% of surgeons used cathartics (70%), enemas (2%) or both (28%) for MBP. MBP was used 60% in right colon surgery, 90% in left colon and 99% in rectal surgery. Surgeons with more case load or those who specialized in colorectal surgery used significantly less MBP; 60% of the surgeons thought that MBP made surgery easier and reduced contamination; 35% thought that it decreased wound infection (WI) and 17% thought that it prevented anastomotic leaks. For 77%, it was regarded as useful or very useful. AP was used by 99.3% of surgeons including systemic alone in 86.2% and combined with oral in 16.8%. The first dose was given 2 h before surgery by 20.2% of the surgeons, at the anaesthetic induction by 78.3% and postoperatively by 1.5%; 43% used single dose only, 44.5% extended to 24 h and 12.5% for two or more days; 95% thought that AP reduced WI and 96% considered that it was useful.

CONCLUSION

There is general agreement on AP. MBP remained a common practice among Spanish colorectal surgeons except for right colonic resection. Surgeons with more case load and specialization used it significantly less.

Anemia in the critically ill: the role of erythropoietin

Anemia is a common clinical problem in critically ill patients and is associated with substantial red blood cell (RBC) transfusion requirements. However, RBC transfusion has significant risks, including adverse effects on the immune system. Although a low hemoglobin concentration may be tolerable, it may not be optimal for the critically ill patient. Thus, alternative therapies that can increase hemoglobin and avoid complications of RBC transfusion are desirable. Critically ill patients appear to have anemia identical to the anemia of chronic inflammatory disease with blunted erythropoietin production. Results of a recent randomized controlled trial in critically ill patients demonstrated that recombinant human erythropoietin (r-HuEPO, epoetin alfa) significantly reduced (by approximately 50%) the number of RBC units transfused (P <.002) and significantly increased hematocrit (P <.01) compared with placebo. There was no increase in mortality or adverse clinical events with therapy. Epoetin alfa may be an effective therapeutic approach to anemia in critically ill patients, decreasing the need for transfusion and achieving higher hemoglobin concentrations than generally attained with transfusion.

Reduced blood loss during burn surgery

The purpose of this study was to investigate the use of subcutaneous injection of burn wounds and skin graft donor sites with an adrenaline-saline solution to reduce blood loss during burn surgery. This retrospective study reviewed the requirements of blood products in 30 randomly selected adult patients with more than 10% body area burned, who had at least one burn operation at a university regional burn center, between January 1991 and June 1997. Patients were matched by age and percent body area burned and stratified according to the surgical technique in two groups. In Group 1, 15 patients received the modified tumescent surgical technique: subcutaneous injection of adrenaline (1 part/million in warm saline solution) into the subcutaneous tissue of the donor sites for autologous skin graft and areas of burn eschar to be excised, combined with pneumatic tourniquets in extremities and saline-adrenaline soaked nonadherent pads. In Group 2, 15 patients received the traditional surgical technique: soaked gauze compresses with an adrenaline-thrombin solution (1 ml of 1:1,000 adrenaline, thrombin 10,000 units, and 1 L of normal saline). Outcome measures, transfusion of blood products, operating time and complications between the two patient groups were analyzed using the Wilcoxon 2-sample test. The two patient groups were not different by age (40.4 +/- 19.4 vs 38.9 +/- 17.9), percent total body area burned (27.6 +/- 15.4 vs 32.8 +/- 13.4), or percent full thickness burn (7.0 +/- 8.5 vs 11.5 +/- 8.5). The modified tumescent surgical technique significantly reduced mean total blood units transfused per patient (7.9 +/- 11.5 vs 15.7 +/- 12.9 units; P = .031), and the mean blood units transfused intraoperatively per patient (4.7 +/- 7.8 vs 8.9 +/- 8.0 units; P = .026). The modified tumescent surgical technique significantly reduced the intraoperative and total blood transfusion requirements in our thermally injured patients.

Septic complications of elective laparoscopic colorectal resection

BACKGROUND

We set out to determine the rate and pattern of septic complications of the surgical wound, abdominal cavity, and urinary and respiratory tracts following laparoscopic colorectal resection.

METHODS

A longitudinal database of 500 consecutive cases of colorectal resections was reviewed.

RESULTS

The total wound infection rate was 7.2% (36/500) and included infections of the abdominal wall wounds (32/500, 6.4%) and the perineal wounds (4/50, 8%). The anastomotic leak rate in 418 patients who underwent resection with primary anastomosis was 3.3% (14/418). Intraabdominal abscesses were diagnosed in 1% (5/500) of patients. Urinary tract infections were rare (3/500, 0.6%), as was postoperative pneumonia (6/500, 1%).

CONCLUSIONS

This study confirms the low rate of postoperative pneumonia observed with all other minimally invasive procedures. Intraabdominal abscesses, urinary tract infections, and postoperative pneumonia occur considerably less frequently than in reported historical controls for open surgery. The rates of abdominal wound infection and anastomotic leak in laparoscopic colorectal resection appear to be equivalent to traditional surgery, whereas the rate of perineal wound sepsis is lower. Comparative studies are needed to determine the differential costs of the septic episodes associated with the two approaches.

Double-blind comparison of single-dose alatrofloxacin and cefotetan as prophylaxis of infection following elective colorectal surgery. Trovafloxacin Surgical Group

BACKGROUND

Alatrofloxacin, the prodrug of trovafloxacin, is a novel fluoroquinolone antimicrobial agent with a broad spectrum, including activity against gram-positive and gram-negative aerobes and anaerobes. Its pharmacokinetic properties (long half-life, excellent tissue distribution, and good safety profile) suggest a role in surgical prophylaxis. This prospective, multicenter, double-blind trial compared alatrofloxacin with cefotetan, an approved drug for surgical prophylaxis, in reducing postoperative infections.

METHODS

The efficacy and safety of a single 200-mg intravenous dose of alatrofloxacin were compared to a single 2-g intravenous dose of cefotetan in 492 patients undergoing elective colorectal surgery. The efficacy of alatrofloxacin as a prophylaxis for wound, intra-abdominal, or remote-site postoperative infectious complications was compared with cefotetan in 317 clinically evaluable patients; 161 received alatrofloxacin and 156 received cefotetan. The patients were monitored for infections and safety for 30 days postoperatively.

RESULTS

No statistically significant between-treatment difference was detected in successful clinical response rates at the end of the study (72% for each group). The incidence of primary wound infections at the time of hospital discharge was also similar: 21% in patients treated with alatrofloxacin and 18% in those treated with cefotetan. Safety, established by the incidence of adverse events, did not differ statistically between the groups.

CONCLUSIONS

A single intravenous dose of alatrofloxacin given within 4 hours prior to surgery was as effective as an intravenous dose of cefotetan in the prevention of postoperative infectious complications in patients undergoing elective colorectal surgery. The safety profiles of the two medications were similar.

Antimicrobial prophylaxis in colorectal surgery: a systematic review of randomized controlled trials

BACKGROUND

A systematic review was carried out to assess the relative efficacy of antimicrobial prophylaxis for the prevention of postoperative wound infection in patients undergoing colorectal surgery.

METHODS

MEDLINE, EMBASE, the Cochrane Trials Register and the references cited in retrieved studies were searched to identify relevant trials published between 1984 and 1995.

RESULTS

Some 147 relevant trials were identified. The quality of trials has improved over the past 12 years. The results confirm that the use of antimicrobial prophylaxis is effective for the prevention of surgical wound infection after colorectal surgery. There was no significant difference in the rate of surgical wound infections between many different regimens. However, certain regimens appear to be inadequate (e.g. metronidazole alone, doxycycline alone, piperacillin alone, oral neomycin plus erythromycin on the day before operation). A single dose administered immediately before the operation (or short-term use) is as effective as long-term postoperative antimicrobial prophylaxis (odds ratio 1.17 (95 per cent confidence interval (c.i.) 0.90-1.53)). There is no convincing evidence to suggest that the new-generation cephalosporins are more effective than first-generation cephalosporins (odds ratio 1.07 (95 per cent c.i. 0.54-2.12)).

CONCLUSION

Antibiotics selected for prophylaxis in colorectal surgery should be active against both aerobic and anaerobic bacteria. Administration should be timed to make sure that the tissue concentration of antibiotics around the wound area is sufficiently high when bacterial contamination occurs. Guidelines should be developed locally in order to achieve a more cost-effective use of antimicrobial prophylaxis in colorectal surgery.

A double-blind, randomized study of three antimicrobial regimens in the prevention of infections after elective colorectal surgery

The objective of this study was to assess the prophylactic efficacy of cefoxitin, ceftizoxime, and metronidazole-gentamicin in colorectal surgery. A double-blind, randomized prospective clinical trial design was used in a Canadian tertiary care teaching hospital. Patients were randomized to one of three treatment groups and received three doses of a study drug (30 min preoperative and 2 postoperative doses at 12 and 24 h). Cefoxitin and ceftizoxime were given as 1000-mg doses. Metronidazole-gentamicin was given as 500 mg of metronidazole plus 120 mg of gentamicin in a minibag. High-risk patients (bowel ischemia, diabetic, current steroid use, etc.) received 10 postoperative doses. Patients with infections, prior antibiotics, or study drug allergies were excluded. Over 30 months, 153 patients were enrolled. Thirty-one patients were excluded for protocol violations. Of the 122 evaluable patients (38 ceftizoxime, 45 metronidazole-gentamicin, 39 cefoxitin), there was no difference across groups regarding sex, age, weight, preoperative Apache II score, and prior history of bowel surgery. Groups were equivalent regarding surgeon, nursing unit, high-risk status (six ceftizoxime, seven metronidazole-gentamicin, seven cefoxitin), bowel preparation, and procedure (including blood loss, drains, organ injury, intraoperative complications). Clinically significant infection requiring systemic antibiotics (7-day hospital and 30-day follow-up) was identified in 0% of ceftizoxime, 15% of metronidazole-gentamicin, and 26% of cefoxitin receiving patients (p = 0.005). Mean ASEPSIS scores for each group were 2.3 (range 0-15) for ceftizoxime, 9.2 (range 0-45) for metronidazole-gentamicin, and 10.4 (range 0-75) for cefoxitin (p = 0.01). Ceftizoxime patients tended to have a shorter total hospital stay (12.2 days versus 19.7 days for cefoxitin versus 13.9 days for metronidazole-gentamicin; p = 0.04), although the procedure to discharge interval was not significantly different (p = 0.09). There was no difference in clinical outcome according to risk status. Anaerobic bacteria were observed more commonly in the ceftizoxime and cefoxitin groups, whereas enteric Gram-negative aerobes were observed most often in the metronidazole-gentamicin group. The study regimens were generally well tolerated. Drug costs were equivalent between ceftizoxime and cefoxitin and lowest with the metronidazole-gentamicin regimen. Ceftizoxime appears to be more effective for the prevention of infection in colorectal surgery than either cefoxitin or metronidazole-gentamicin in the dosage regimens studied.

Blood transfusion and infection after colorectal cancer surgery

BACKGROUND

Many observational studies have described an association between perioperative transfusion and postoperative infection. Detection of such a relationship may depend on which variables are considered as potential confounders of the association under study. However, most reports have not considered risk factors for postoperative infection at specific sites as possible explanations for the observed relationship.

STUDY DESIGN AND METHODS

The records of 492 patients undergoing elective colorectal cancer resection at the Massachusetts General Hospital between January 1992 and December 1994 were reviewed. The probability of infection in association with transfusion was calculated with and without adjustment for the effects of chronic systemic illness, number of days with urinary catheter, endotracheal intubation, impaired consciousness, and specific risk factors for wound infection. Postoperative infection at any site and infections at specific sites were analyzed as separate outcomes.

RESULTS

After adjustment for the effects of the variables listed above, allogeneic transfusion was not associated with postoperative infection at any site (p = 0.407). Only a specific association of transfusion with wound infection could be detected. However, in an analysis that adjusted for the effects of only the 18 confounders considered by previous authors, transfusion was the most significant predictor of infection. In that analysis, the risk of postoperative infection increased by 14 percent per unit of red cells transfused (p < 0.001).

CONCLUSION

The overall adverse relationship between transfusion and infection reported by previous observational studies may have been due to an incomplete consideration of the variables that confound that association. This finding may help explain the disagreement between the conclusions of recent large, randomized, controlled trials (which failed to detect a deleterious transfusion effect) and the earlier observational studies.

Analysis of variables affecting wound healing after musculoskeletal sarcoma resections

Adjuvant treatment modalities, nutritional parameters, and allogenic blood transfusions are investigated as possible contributing variables which may adversely affect wound healing after tumor resections for musculoskeletal sarcomas. Statistical analysis determined that preoperative chemotherapy, depressed preoperative hematocrit, and allogenic blood transfusions (probably immunosuppression mediated) were the only significant factors affecting wound healing outcome. Suggestions to improve postoperative infection rates are discussed.

The randomized controlled clinical trial in gastroenterology: the Danish contributions from 1970 to 1994

More than 200 Danish randomized controlled clinical trials in gastroenterology published from 1970 to 1994 were retrieved by electronic media, by hand-searching relevant journals, and by direct requests to Danish gastroenterologists. With the historical perspective through a quarter of a century, these papers are outlined to provide a survey of the pieces of information that Danish gastroenterologists have contributed to the present knowledge of therapeutics. The presented randomized controlled clinical trials constitute an impressive sum of knowledge within a diversity of topics. A cautious analysis of the time pattern for the publications in addition to the contents of the reports discloses that the discipline of planning and executing relevant controlled clinical trials is now in blossom in Danish gastroenterology.

Value of oral antibiotic prophylaxis in colorectal surgery

A total of 169 patients undergoing colorectal surgery were randomly allocated to receive either gentamicin plus metronidazole or oral ciprofloxacin plus metronidazole as prophylaxis; they were also allocated to receive cover for 1 or 3 days. Twenty-eight patients (17 per cent) developed postoperative wound infections. The proportion of patients with wound infections and other infective complications was significantly less (P < 0.02) in those receiving oral ciprofloxacin. Cover for 3 days was no better than that for only 1 day. Oral ciprofloxacin for prophylaxis may offer advantages in efficacy and ease of administration compared with parenteral antibiotics.

Leucodepletion of blood products by filtration

The leucocytes present in red cell and platelet components have been implicated in several important immunological and infective complications of blood transfusion. Recent developments in blood filtration technology allow the production of leucodepleted blood products (residual leucocytes < 5 x 10(6) per transfused unit) in the laboratory or at the bedside with the potential to prevent these adverse effects. Quality assurance remains an important problem, particularly for bedside filtration. Prestorage filtration may have significant advantages for red cell and platelet production. There is strong clinical evidence that 3 log10 leucodepletion prevents or delays febrile reactions in patients receiving multiple red cell transfusions and can reduce cytomegalovirus transmission. Leucodepletion to prevent HLA alloimmunisation, platelet refractoriness and febrile reactions in patients receiving red cell and platelet support remains controversial. Transfused leucocytes induce 'immunosuppressive' changes in the recipient, but recent studies cast doubt on the association with cancer recurrence after surgery. However, leucodepleted blood may reduce the incidence of postoperative infection. Leucodepletion by filtration is expensive and there is a requirement for well-designed prospective clinical studies focusing on appropriate filtration technology (and alternatives), clinical outcome and cost-effectiveness.

Infection after colorectal surgery: a randomized trial of prophylaxis with piperacillin versus sulbactam/piperacillin. West of Scotland Surgical Infection Study Group

Antibiotics used for prophylaxis in elective colorectal surgery should be effective against the organisms contaminating the soft tissues and isolated from postoperative infections. These are usually the enterobacteriaceae commensal to the colon. However, staphylococcal and anaerobic infections are not uncommon. Piperacillin has been used as antibiotic prophylaxis and been shown to be as efficacious as an aminoglycoside with metronidazole. Piperacillin is susceptible to many beta-lactamases and we have therefore conducted a study to assess the efficacy of adding sulbactam, a beta-lactamase inhibitor, to piperacillin for prophylaxis in elective colorectal surgery. Three hundred and seventy-nine patients were randomized to receive a single dose of piperacillin 4 g intravenously (iv) (group P, n = 192) or piperacillin 4 g with sulbactam 2 g iv (group SP n = 187). Fifty-three patients were withdrawn from analysis leaving 168 evaluable patients in group P and 158 patients in group SP. Postoperative infective complications occurred in 91 (28%) patients, 55 (33%) in group P and 36 (23%) in group SP (chi 2 = 4.0 P < 0.05). Surprisingly Staphylococcus aureus was isolated from wound infections in 22 patients (12 in group P and 10 in group SP) which represents 24% of those patients who developed infective morbidity. We conclude that sulbactam improves the efficacy of piperacillin as prophylaxis in elective colorectal surgery but does little to protect against staphylococcal wound infection.

Occurrence of intraperitoneal septic complications after hepatic resections between 1985 and 1990

In this study, the risk factors related to intraperitoneal septic complications occurring after hepatectomy (IPSCH) as well as the effect of various perioperative variables on the outcome of IPSCH between 1985 and 1990 were analyzed. Twenty-one of 211 patients (10.0%) developed IPSCH. The findings in the patients with IPSCH were compared with those in 190 patients without IPSCH. The significant variables associated with the development of IPSCH included a high incidence of accompanying chronic renal failure (14.3% vs 2.1%), a larger blood loss during surgery (2,130 vs 1,340 ml) as well as a greater amount of intraoperative blood replacement (1,130 vs 570 ml), and a greater weight of the resected liver (367 vs 233 g). IPSCH occurred in 10 of 12 patients who had postoperative bile leakage. Eighteen patients (85.7%) with IPSCH were discharged from the hospital after non-operative management; however, the hospital death rate (14.3% vs 1.1%) was significantly higher in patients with IPSCH. This review suggests that the incidence of IPSCH has not decreased recently. Thus, to prevent IPSCH, at least following bile leakage, it is necessary to perform a careful division of the liver parenchyma followed by a bile leakage test, and when this complication occurs unexpectedly in patients who have a good functional reserve of the remnant liver, IPSCH can be effectively drained percutaneously under ultrasound guidance.

Randomised controlled trial comparing transfusion of leucocyte-depleted or buffy-coat-depleted blood in surgery for colorectal cancer

In retrospective studies, perioperative blood transfusions were associated with poor prognosis after surgery for cancer and were a major independent risk factor for postoperative bacterial infection. Leucocyte-depleted, in contrast to buffy-coat-depleted, blood has no immunosuppressive effects in transplantation and so might lack detrimental effects on cancer prognosis and postoperative infections. We studied this hypothesis in a controlled trial by randomly allocating patients to receive either leucocyte-depleted red cells or packed cells without buffy coat when blood was needed. Between 1987 and 1990, 871 eligible patients with colorectal cancer, including 697 patients operated upon with curative intent, were randomised in the 16 participating hospitals. Neither the eligible group nor the curative group showed significant differences between the two trial transfusions in survival, disease-free survival, cancer recurrence rates, or overall infection rates after an average follow-up of 36 months. Patients who had a curative resection and who received blood of any sort had a lower 3-year survival than non-transfused patients (69% vs 81%, p = 0.001) and a higher infection rate (39% vs 24%, p < 0.001). Colorectal cancer recurrence rates, however, were not influenced by blood transfusion (30% vs 26%, p = 0.22). These combined observations confirm the association between blood transfusion and poor patient survival but indicate that the relation is not due to promotion of cancer.

The effect of previous blood transfusion on lymphocyte subsets and natural killer cell function in patients with colorectal cancer

To elucidate the possible influence of previous blood transfusion on immune functions, the transfusion history of 153 patients admitted to hospital for elective colorectal surgery was correlated with lymphocyte subsets and natural killer (NK) cell function. The subsets determined were CD2, CD3, CD4, CD8, CD16, CD20, CD56, CD57 and HLA-DR-positive. The NK cell function was determined by measuring the killing capacity against cFDA-labelled K562 target cells monitored via a flow-cytometer. We found that 42 patients (27%) had been transfused before surgery, of these 13 had been transfused less than 30 days before surgery and 29 (19%) transfused more than 30 days before (median 10 years, range 0.1-37 years). In transfused patients, we found a significantly reduced number of B lymphocytes (CD20; p = 0.01), a reduction in HLA-DR-positive cells (p = 0.02) and a just significant reduction of NK cell function in transfused compared to nontransfused patients. The reduction in NK cell function is marginal and the NK cell function is within normal range, and probably without clinical significance. Reduction in NK cell function has been described before, whereas the reduction in B cells has not been reported earlier. The results may suggest an impaired humoral immunity and a minor reduction in cellular immunity in patients following blood transfusion.

Comparison of prophylactic ampicillin/sulbactam with gentamicin and metronidazole in elective colorectal surgery: a randomized clinical study

A randomized control clinical study was conducted to compare the effectiveness of prophylactic ampicillin/sulbactam in preventing wound infection after elective colorectal surgery with a combination of gentamicin and metronidazole. Over a 2-year period, 143 patients were recruited, but 15 patients were subsequently excluded due to the use of additional antibiotics for the treatment of pulmonary or urinary infection or early postoperative death without wound infection. Of the 128 evaluable patients, six of the 63 patients (9.5%) in the ampicillin/sulbactam group and seven of the 65 patients (10.7%) in the gentamicin and metronidazole group developed wound infection. We conclude that prophylactic ampicillin/sulbactam is effective in reducing the risk of wound infection following colorectal surgery.

[Antibiotic prophylaxis in surgery of the esophagus]

Surgery of oesophagus carcinoma is a long and major procedure. Perioperative radiochemotherapy is often required. Therefore many factors favour the occurrence of local and general postoperative infection, justifying an antibiotic prophylaxis directed against oesophageal and gastric flora. In case of oesophageal stenosis, the oesophageal floral often switches to the fecal type. Antimicrobial agents diffuse to the surgical site and reach there high concentrations for the time of surgery. We recommend, just prior the induction of anaesthesia the intravenous administration of a single dose of a third generation cephalosporin (ceftriaxone 2 g) and nitroimidazole (ornidazole 1 g). The long half-life of these agents allows sufficient concentrations at surgical site to be obtained and the efficacy of this regimen has been demonstrated. Selective decontamination of the digestive tract with systemic antibiotherapy is another approach for the prevention of postoperative complications of surgery of oesophagus carcinoma.

Imipenem prophylaxis in elective colorectal surgery

In a randomized controlled study of 411 patients undergoing elective colorectal surgery, the efficacy and safety of two different regimens of imipenem were compared with those of a control regimen of cefuroxime plus metronidazole. Surgical infections occurred in 92 (26.4 per cent) of 349 evaluable patients. There were no major differences between the three treatment groups. It is concluded that imipenem is as effective as cefuroxime plus metronidazole in the prevention of sepsis after elective colorectal procedures.

A randomized trial of one versus three doses of Augmentin as wound prophylaxis in at-risk abdominal surgery

In a randomized prospective trial of prophylactic antibiotics in at-risk abdominal surgery, one dose of intravenous Augmentin (amoxycillin 250 mg and clavulanic acid 125 mg) on induction has been compared with three 8 hourly doses in 900 patients. Wound infection rates which included minor and delayed infections were very similar in those given one dose: 48/449 (10.7%) compared with those given three doses: 49/451 (10.9%) 95% confidence limits - 4.25% + 3.9%. There were more septic and sepsis-related deaths in those patients given one dose (14 deaths) than in those given three doses (7 deaths) P > 0.1 95% CL - 0.4% + 3.0%. However, there were more very elderly patients in the one dose group: 64% of the deaths were aged over 80 and all but one had an emergency operation. There was no difference in the other outcome measures studied which included non-fatal deep sepsis, length of postoperative hospital stay, duration of postoperative fever or the use of antibiotics for postoperative infection. One dose of a suitable intravenous antibiotic gives prophylaxis against wound infection in at-risk abdominal surgery which is at least as effective as multiple doses. However, there may be a risk of overwhelming systemic sepsis in very elderly patients having emergency surgery.

Postoperative infection and natural killer cell function following blood transfusion in patients undergoing elective colorectal surgery

The frequency of infection in 197 patients undergoing elective colorectal surgery and having either no blood transfusion, transfusion with whole blood, or filtered blood free from leucocytes and platelets was investigated in a prospective randomized trial. Natural killer cell function was measured before operation and 3, 7 and 30 days after surgery in 60 consecutive patients. Of the patients 104 required blood transfusion; 48 received filtered blood and 56 underwent whole blood transfusion. Postoperative infections developed in 13 patients transfused with whole blood (23 per cent, 95 per cent confidence interval 13-32 per cent), in one patient transfused with blood free from leucocytes and platelets (2 per cent, 95 per cent confidence interval 0.05-11 per cent) and in two non-transfused patients (2 per cent, 95 per cent confidence interval 0.3-8 per cent) (P less than 0.01). Natural killer cell function was significantly (P less than 0.001) impaired up to 30 days after surgery in patients transfused with whole blood. These data provide a strong case against the use of whole blood transfusion in patients undergoing elective colorectal surgery.

Single dose imipenem-cilastatin compared with three doses of cefuroxime and metronidazole as prophylaxis in elective colorectal surgery: a prospective randomized study

A prospective randomized study was performed with 61 patients undergoing elective surgery for colorectal cancer, to evaluate the prophylactic effect of two different parenteral antibiotic regimens. All patients were randomly allocated into two groups, comparable in age, sex, nutritional status and operative procedures. The patients in Group A (n. 31) received 1 g i.v. of imipenem-cilastatin at induction of anesthesia. Patients in Group B (n. 30) were given cefuroxime (1.5 g i.v.) plus metronidazole (0.5 g i.v.) at the time of anesthesia and two other administrations of the combined antibiotics (cefuroxime 0.75 g plus metronidazole 0.5 g i.v.) every 8 hours. The severity of sepsis was evaluated according to the scoring system proposed by Elebute and Stoner. No significant differences were found in terms of the rate of surgical infections: 9% in Group A and 16% in Group B. Infections not of surgical origin were found only in Group B (10.4%). These data suggest that a single dose of intravenous imipenem-cilastatin appears to be as effective as three doses of cefuroxime and metronidazole as prophylaxis against infection in elective colorectal surgery.