The effect of postoperative peritoneal lavage on survival, peritoneal wound healing and adhesion formation following fecal peritonitis: an experimental study in the rat

Failure of peritoneal lavage to prevent operative site infection and peritoneal tumor recurrence in pancreatic surgery

BACKGROUND

Although intraoperative peritoneal lavage often is performed routinely with the aim of reducing peritoneal contamination, evidence of lavage benefit in elective pancreatic surgery is limited.

METHODS

We retrospectively classified patients who had undergone pancreatic surgery to groups given or not given peritoneal lavage, then comparing clinical results. This saline lavage was performed at the end of the operation. The primary endpoint was rate of surgical site infection. Frequency of peritoneal recurrence also was evaluated.

RESULTS

Among all 104 patients in the study, incidence of infectious complications in the lavage group (n = 65) was significantly higher than in the non-lavage group (n = 39; 35% vs. 15%, P = 0.041), while incidences of postoperative complications overall and surgical site infection did not differ between lavage (80% and 26%) and non-lavage groups (67% and 10%, P = 0.162 and 0.076, respectively). Among 63 patients undergoing pancratoduodenectomy, frequencies of positive bacterial cultures of drainage fluids on postoperative days 1 and 3 were greater in the non-lavage group (P < 0.001 and P = 0.012), but surgical site infection was significantly more frequent in the lavage group (P = 0.043). Among patients with pancreatic and biliary cancers, lavage did not affect frequency of peritoneal recurrence.

CONCLUSION

Intraoperative lavage did not prevent surgical site infection or peritoneal recurrence of pancreatobiliary cancer.

Intraoperative surgical site infection control and prevention: a position paper and future addendum to WSES intra-abdominal infections guidelines

BACKGROUND

Surgical site infections (SSI) represent a considerable burden for healthcare systems. They are largely preventable and multiple interventions have been proposed over past years in an attempt to prevent SSI. We aim to provide a position paper on Operative Room (OR) prevention of SSI in patients presenting with intra-abdominal infection to be considered a future addendum to the well-known World Society of Emergency Surgery (WSES) Guidelines on the management of intra-abdominal infections.

METHODS

The literature was searched for focused publications on SSI until March 2019. Critical analysis and grading of the literature has been performed by a working group of experts; the literature review and the statements were evaluated by a Steering Committee of the WSES.

RESULTS

Wound protectors and antibacterial sutures seem to have effective roles to prevent SSI in intra-abdominal infections. The application of negative-pressure wound therapy in preventing SSI can be useful in reducing postoperative wound complications. It is important to pursue normothermia with the available resources in the intraoperative period to decrease SSI rate. The optimal knowledge of the pharmacokinetic/pharmacodynamic characteristics of antibiotics helps to decide when additional intraoperative antibiotic doses should be administered in patients with intra-abdominal infections undergoing emergency surgery to prevent SSI.

CONCLUSIONS

The current position paper offers an extensive overview of the available evidence regarding surgical site infection control and prevention in patients having intra-abdominal infections.

Standardized irrigation technique reduces intraabdominal abscess after appendectomy

PURPOSE

The utility of irrigation at the time of appendectomy for acute appendicitis has been debated, with recent studies showing no benefit to irrigation. In our practice, two techniques have been used; one in which irrigation was at the discretion of the surgeon, and one in which irrigation was standardized. The standardized irrigation technique involved large volume (3-12 l) irrigation in small, focused, directed aliquots to achieve optimal dilution. We sought to retrospectively assess whether the standardized large volume irrigation technique was associated with measurably reduced intraabdominal infection. We hypothesized that there would be no difference in intraabdominal infection rate.

METHODS

Medical records for cases of appendectomies performed for acute appendicitis, years 2007 through 2017, were reviewed (n = 432). Rate of subsequent abdominal infection was compared between patients who underwent the standardized large volume irrigation technique compared to those who did not using Fisher's exact test; p < 0.05 was considered significant.

RESULTS

For patients that underwent the standardized large volume irrigation technique there were no (0/140) subsequent abdominal infections within the study period, compared with a rate of 6.2% (18/292) for all other patients (p value 0.001). Among cases that had a perforated appendix (n = 105), the rates were 0% (0/31) compared to 18.9% (14/74; p value 0.009).

CONCLUSIONS

Utilization of a standardized large volume irrigation technique with the objective of serial dilution is associated with a significantly lower rate of subsequent abdominal infection, even among cases with a perforated appendix. Prospective studies are needed to evaluate this technique.

LEVEL OF EVIDENCE

Level III.

TYPE OF STUDY

Treatment study.

The Origin of Regenerating Mesothelium: A Historical Perspective

Bichat first described the mesothelium in 1827 but despite its early discovery, it has only been in recent years that its importance both in health and disease has been realised. One area still poorly understood is that of the mechanisms regulating mesothelial repair. Mesothelial cells are derived from the mesoderm but express many epithelial characteristics. However, mesothelium does not heal in the same way as other epithelial-like cells. Epithelium heals by centripetal migration, with cells at the edge of the wound proliferating and migrating into the injured area. Hertzler in 1919 noted that both large and small peritoneal injuries healed within the same time frame, concluding that the mesothelium could not heal solely by centripetal migration. The exact mechanisms involved in mesothelial regeneration following injury are controversial with a number of proposals suggested to explain the origin of the regenerating cells. This review will examine these proposals and give some insights into the likely mechanisms involved.

Stem Cells for Mesothelial Repair: An Understudied Modality

Adhesions are bands of fibrous tissue that form between opposing organs and the peritoneum, restricting vital intrapleural and abdominal movement. They remain a major problem in abdominal surgery, occurring in more than three fourths of patients following laparotomy. Adhesions result when injury to the mesothelium is not repaired by mesothelial cells and can be viewed as scar tissue formation. The mechanism of mesothelial healing suggested the involvement of stem cells in the process. It has long been known that peritoneal wounds heal in the same amount of time regardless of size. Therefore, the mesothelium could not regenerate solely by proliferation and centripetal migration of cells at the wound edge as occurs in the healing of skin epithelium. Several studies suggest the presence of i) mesothelial stem cells that can differentiate into mesothelial cells and a few other phenotypes and/or ii) that mesothelial cells are themselves stem cells. Other studies have suggested that adult stem cells in the muscle underlying the peritoneum can differentiate into mesothelial cells and contribute to healing. Prevention of abdominal adhesions have been accomplished by delivery of autologous mesothelial cells and multipotent adult stem cells isolated from skeletal muscle. Adult stem cells from sources other than the serosal tissue offer an alternative treatment modality to prevent the formation of abdominal adhesions.

Effect of peritoneal lavage with clindamycin-gentamicin solution on infections after elective colorectal cancer surgery

BACKGROUND

Colorectal surgery may lead to infections because despite meticulous aseptic measures, extravasation of microorganisms from the colon lumen is unavoidable.

STUDY DESIGN

A prospective, randomized study was performed between January 2010 and December 2010. Patient inclusion criteria were a diagnosis of colorectal neoplasms and plans to undergo an elective curative operation. Patients were divided into 2 groups: Group 1 (intra-abdominal irrigation with normal saline) and Group 2 (intraperitoneal irrigation with a solution of 240 mg gentamicin and 600 mg clindamycin). The occurrence of wound infections and intra-abdominal abscesses were investigated. After the anastomosis, a microbiologic sample of the peritoneal surface was obtained (sample 1). A second sample was collected after irrigation with normal saline (sample 2). Finally, the peritoneal cavity was irrigated with a gentamicin-clindamycin solution and a third sample was obtained (sample 3).

RESULTS

There were 103 patients analyzed: 51 in Group 1 and 52 in Group 2. There were no significant differences between the groups in age, sex, comorbidities, or type of colorectal surgery performed. Wound infection rates were 14% in Group 1 and 4% in Group 2 (p = 0.009; odds ratio [OR] 4.94; 95% CI 1.27 to 19.19). Intra-abdominal abscess rates were 6% in Group 1 and 0% in Group 2 (p = 0.014; OR 2.14; 95% CI 1.13 to 3.57). The culture of sample 1 was positive in 68% of the cases, sample 2 was positive in 59%, and sample 3 in 4%.

CONCLUSIONS

Antibiotic lavage of the peritoneum is associated with a lower incidence of intra-abdominal abscesses and wound infections.

Meta-analysis of the effect of peritoneal lavage on survival in experimental peritonitis

Background

Morbidity and mortality associated with bacterial peritonitis remain a challenge for contemporary surgery. Despite great surgical improvements, death rates have not improved. A secondary debate concerns the volume and nature of peritoneal lavage or washout—what volume, what carrier and what, if any, antibiotic or antiseptic?

Methods

A literature search of experimental studies assessing the effect of peritoneal lavage following peritonitis was conducted using Medline, EMBASE and Cochrane databases. Twenty-three trials met predetermined inclusion criteria. Data were pooled and relative risks calculated.

Results

In an experimental peritonitis setting a mortality rate of 48·9 per cent (238 of 487) was found for saline lavage compared with 16·4 per cent (106 of 647) for antibiotic lavage (absolute risk reduction (ARR) 32·5 (95 per cent confidence interval (c.i.) 27·1 to 37·7) per cent; (P &lt; 0·001). An ARR of 25·0 (95 per cent c.i. 17·9 to 31·7) per cent P &lt; 0·001) was found for the use of saline compared with no lavage at all. The survival benefit persisted regardless of systemic antibiotic therapy. Antiseptic lavage was associated with a very high mortality rate (75·0 per cent).

Conclusion

Pooled data from studies in experimental peritonitis demonstrated a significant reduction in mortality with antibiotic lavage.

Lavage enhances the production of proinflammatory mediators by peritoneal mesothelial cells in an experimental model

PURPOSE

There is a lack of clinical evidence supporting the use of lavage in patients with peritonitis. It is known that fluids such as normal saline cause temporary damage to the peritoneum and that increased production of proinflammatory mediators is associated with a poor outcome. This study used an experimental model to evaluate the effect of lavage on the peritoneal mesothelium and the ability of peritoneal mesothelial cells to produce a battery of proinflammatory mediators (TNFalpha, IL-1beta, GROalpha, and ICAM-I.).

METHODS

Wistar rats were allocated into four groups (control, peritonitis, lavage, peritonitis plus lavage). Peritonitis was induced by exposure to zymosan and saline was used for lavage. After 18, 24, and 43 hours, mesothelial imprints were taken from the peritoneum for histology, semiquantitative reverse transcription-polymerase chain reaction, Western blot analyses, and immunocytochemistry.

RESULTS

Both peritonitis and lavage caused peritoneal damage at 18 and 24 hours, and this effect was additive. At varying times, peritoneal mesothelial cells from animals undergoing lavage had greater up-regulation (P < 0.05) of mRNA expression for TNFalpha, IL-1beta, GROalpha, and ICAM-I and greater production (P < 0.05) of TNFalpha, IL-1RII, GROalpha, and ICAM-I. The latter was heavily concentrated at the cell membrane.

CONCLUSIONS

Lavage causes self-limiting peritoneal damage and this is associated with an up-regulation of proinflammatory mediators in animals with peritonitis.

Mesothelial progenitor cells and their potential in tissue engineering

The mesothelium consists of a single layer of flattened mesothelial cells that lines serosal cavities and the majority of internal organs, playing important roles in maintaining normal serosal integrity and function. A mesothelial 'stem' cell has not been identified, but evidence from numerous studies suggests that a progenitor mesothelial cell exists. Although mesothelial cells are of a mesodermal origin, they express characteristics of both epithelial and mesenchymal phenotypes. In addition, following injury, new mesothelium regenerates via centripetal ingrowth of cells from the wound edge and from a free-floating population of cells present in the serosal fluid, the origin of which is currently unknown. Recent findings have shown that mesothelial cells can undergo an epithelial to mesenchymal transition, and transform into myofibroblasts and possibly smooth muscle cells, suggesting plasticity in nature. Further evidence for a mesothelial progenitor comes from tissue engineering applications where mesothelial cells seeded onto tubular constructs have been used to generate vascular replacements and grafts to bridge transected nerve fibres. These findings suggest that mesothelial cell progenitors are able to switch between different cell phenotypes depending on the local environment. However, only by performing detailed investigations involving selective cell isolation, clonal analysis together with cell labelling and tracking studies, will we begin to determine the true existence of a mesothelial stem cell.

Mesothelial cells: their structure, function and role in serosal repair

The mesothelium is composed of an extensive monolayer of specialized cells (mesothelial cells) that line the body's serous cavities and internal organs. Traditionally, this layer was thought to be a simple tissue with the sole function of providing a slippery, non-adhesive and protective surface to facilitate intracoelomic movement. However, with the gradual accumulation of information about serosal tissues over the years, the mesothelium is now recognized as a dynamic cellular membrane with many important functions. These include transport and movement of fluid and particulate matter across the serosal cavities, leucocyte migration in response to inflammatory mediators, synthesis of pro-inflammatory cytokines, growth factors and extracellular matrix proteins to aid in serosal repair, release of factors to promote both the deposition and clearance of fibrin, and antigen presentation. Furthermore, the secretion of molecules, such as glycosaminoglycans and lubricants, not only protects tissues from abrasion, but also from infection and possibly tumour dissemination. Mesothelium is also unlike other epithelial-like surfaces because healing appears diffusely across the denuded surface, whereas in true epithelia, healing occurs solely at the wound edges as sheets of cells. Although controversial, recent studies have begun to shed light on the mechanisms involved in mesothelial regeneration. In the present review, the current understanding of the structure and function of the mesothelium and the biology of mesothelial cells is discussed, together with recent insights into the mechanisms regulating its repair.

A meta-analysis of peritoneal lavage for acute pancreatitis

BACKGROUND AND AIM

It has been postulated that continuous irrigation of the peritoneal cavity with crystalloid solutions in patients with acute pancreatitis can improve mortality and morbidity. The aim of the study is to perform a meta-analysis of available randomized prospective clinical trials, to evaluate whether lavage influences mortality and morbidity in patients with acute pancreatitis.

METHODS

We performed a computer search of Medline for all available literature on the use of lavage in patients with acute pancreatitis. A meta-analysis was conducted on eight randomized, prospective, clinical trials (a total of 333 patients) evaluating continuous peritoneal lavage in patients with acute pancreatitis. The end-points were mortality and morbidity (i.e. pancreatic necrosis, peripancreatic fluid collections, intra-abdominal abscess formation, septicemia, organ system failure).

RESULTS

Continuous lavage did not improve either mortality (weighted mean difference 1.6%, 95% CI -6.7% to 9.9%, not significant (n.s.)) or morbidity (weighted mean difference 6.2%, 95% CI -3.2% to 15.6%, n.s.) when compared with control patients.

CONCLUSIONS

The use of continuous peritoneal lavage in patients with acute pancreatitis has not been found to be associated with any significant improvement in mortality or morbidity.

Effect of a Composite Membrane of Chitosan and Poloxamer Gel on Postoperative Adhesive Interactions

Excessive postoperative adhesion formation is a major result of surgery. The adhesion reduction effects of a chitosan membrane and poloxamer gel barrier were measured in a rat peritoneal model. Forty-four male Sprague-Dawley rats were divided into four groups (control, poloxamer, chitosan, and poloxamer+chitosan sandwich). Two cm2 of cecal serosa and the adjacent abdominal wall were abraded. The denuded cecum was covered with either a chitosan membrane, a poloxamer gel, chitosan in a sandwich configuration with poloxamer on both sides, or neither (control group) and apposed to the abdominal wall. Fourteen days after surgery adhesions were graded using a whole-number scoring system of zero to five. Adhesion strength was determined using a whole-number system of one to four. Adhesion area was measured on a continuous scale of adhesion severity. Adhesion grades were highest in the control group (5.00 ± 0.00) and were significantly ( P < 0.05) lower in the poloxamer group (3.50 ± 1.35), the chitosan group (1.64 ± 1.63), and the poloxamer+chitosan group (1.18 ± 1.25). The two chitosan-containing groups also had significantly ( P < 0.05) reduced adhesion grades in comparison with the poloxamer group. Adhesion area in both chitosan-containing groups was reduced in comparison with control and adhesion strength was reduced significantly ( P < 0.05) in all groups compared with control. The poloxamer+chitosan group had significantly ( P < 0.05) reduced adhesion strength versus poloxamer only. There was a significant ( P < 0.05) linear correlation ( r = 0.931, P < 0.001) between adhesion grade and adhesion strength. We conclude that chitosan and the combination of poloxamer+chitosan were shown to effectively reduce adhesion area, grade, and strength.

Prostaglandin synthetase inhibition reduces peritonitis-induced early liver oxidant stress

This study was undertaken to determine whether or not the prostanoid metabolism contributes to peritonitis-induced early liver oxidant stress. Lipid peroxidation products, malondialdehyde (MDA) and conjugated dienes (CD), were used to monitor oxidant stress. The rats were given a 5-cc intraperitoneal (i.p.) injection of 25% rat feces suspension and then received either i.p. saline (peritonitis group, n = 11), vitamin E (n = 6), or diclofenac (n = 6). The liver and plasma MDA and CD levels were measured after 3 h. The plasma and liver MDA and CD levels were significantly higher in the peritonitis group than in the control (n = 9). Prostaglandin synthetase inhibitor (diclofenac) kept the liver and plasma MDA and CD at control levels. Antioxidant alpha tacopherol (vitamin E) was thus found not to be effective in reducing these increased MDA and CD levels. Peritonitis-induced early oxidant stress in the liver seems to be mediated by the oxidant-independent activation of the cyclooxygenase pathway.

Effects of vitamin E and cimetidine on peritonitis-induced lipid peroxidation

To investigate the effects of acute fecal peritonitis on plasma and tissue lipid peroxidation and possible protective effects of vitamin E (Vit E) and cimetidine at 4 h in a rat peritonitis model, four groups were designated as: controls, peritonitis, Vit E and cimetidine. Plasma, liver, lung and kidney thiobarbituric acid reactive substances (TBARS) and conjugated diene (CD) levels were measured to monitor oxidative injury. The present fecal peritonitis model caused a significant elevation in liver TBARS; however, neither Vit E nor cimetidine was effective in preventing TBARS formation. Administration of Vit E and cimetidine caused significant decrements from the peritonitis value in liver and lung CD levels.

Management of Generalized Faecal Peritonitis-Can We Do Better?

Generalized faecal peritonitis is associated with a mortality of over 50% in most series of cases. Despite great improvements in the standards of intensive care the morbidity and mortality associated with this condition have not improved, in part due to recurrent intra-abdominal sepsis. This preliminary study investigated the role of laparotomy, repeated abdominal lavage and debridement to determine whether such a policy might lead to an improvement in outcome. Of six cases studied three had perforated diverticular disease, two had Crohn's disease. Twenty lavages were performed on these six patients who had a mean ICU stay of 8 days. Five out of the six patients left hospital and remain well, one patient died of septicaemia and pre-existing renal failure. This study found that laparotomy, repeated abdominal lavage and debridement may be effective in reducing the morbidity and mortality of generalized faecal peritonitis and further study of this technique is appropriate.

Role of macrophages in mesothelial healing

The role of macrophages in rat mesothelial healing was evaluated in vivo and in vitro. In animals whose circulating monocytes were severely depressed, the healing rate was retarded; however, this effect was partly reversed by the introduction of macrophages into the injured site, suggesting that macrophages are of fundamental importance in the healing of mesothelial wounds. Furthermore, it was found that wound exudates stimulated DNA synthesis in normal quiescent mesothelial cells and the component principally responsible for this activity was the macrophage. Cultured macrophage-conditioned media also induced an increase in mesothelial replication. Moreover, the mitogenic activity present in both wound exudates and macrophage-conditioned media was increased by dialysis and diminished by heating at 80 degrees C for 1 h. The putative mesothelial mitogenic factor in the supernatant of wound exudates and macrophage cell cultures has a molecular size greater than 7000 dalton and is stable after mild heating (60 degrees C, 1 h). It is postulated that exudate macrophages secrete mitogenic factor(s) which stimulate mesothelial proliferation, and initiate healing.

Differential pulse polarographic determination of formaldehyde in stored noxythiolin solutions

A differential pulse polarographic method has been developed for the determination of formaldehyde, by means of its kinetic current, in noxythiolin solutions. The assay conditions have been optimized so that the noxythiolin decomposition reaction was not affected. The method had the advantage of rapidity with an analysis time of about 10 min per sample. Thus formaldehyde was determined in noxythiolin solutions prepared and stored under typical clinical conditions. The low concentrations of formaldehyde present in all solutions were insufficient to account for the known cidal action of noxythiolin. There must therefore be some doubt that the mode of action of noxythiolin is simply due to formaldehyde produced as a result of the decomposition of noxythiolin in aqueous solution.

Mesothelial healing: morphological and kinetic investigations

By using structural, kinetic and irradiation techniques it is possible to show that mesothelial healing is a local event. Initially, macrophages occupy the surface of a wound on the injured visceral layer, while mesothelial proliferation proceeds at the edge of the wound and the opposing parietal surface. Fibrin is formed on the wound surface within 24 h, even in the absence of much haemorrhage. Mesothelial ingrowth begins with isolated cells migrating from the wound edge as well as from the serosal surface apposing the wound where mesothelial cells are actively replicating. The cells presumably slide over a bridge of fibrin and macrophages, a process likely to be enhanced by the serosal fluid. Early colonization by macrophages results in the removal of debris and probably prevents the formation of adhesions during mesothelial restoration.

Intraperitoneal antiseptics in experimental bacterial peritonitis

A model of bacterial peritonitis, using mice infected with Escherichia coli, has been used to assess the protective effects of intraperitoneal treatment with antiseptics. Of the five antiseptics tested, only chlorhexidine gluconate had any protective effect, concentrations of 0.05 and 0.02 per cent reducing the mortality to 14 and 50 per cent respectively. The other antiseptics, taurolin, noxytiolin, povidone iodine and hypochlorite were all ineffective. Delayed treatment with chlorhexidine was not as effective as instillation immediately postinfection.

Noxythiolin (Noxyflex), aprotinin (Trasylol) and peritoneal adhesion formation: an experimental study in the rat

Clinical and experimental studies have suggested that noxythiolin and aprotinin may prevent intraperitoneal adhesion formation. A comparison was therefore made of their efficacy in preventing the reformation of adhesions following surgical lysis in a controlled trial using rats. Neither noxythiolon nor aprotinin had any significant benefit over surgical lysis alone. The mortality rate was high in the noxythiolin-treated group.

A comparison of noxythiolin and povidone-iodine in experimentally induced peritoneal infection in mice

Noxythiolin (Noxyflex, Geistlich), given intraperitoneally as a 2.5 per cent solution, protected mice from the lethal effects of an intraperitoneal injection of Escherichia coli. Povidone-iodine (Pevidine, Berk), containing 0.075 per cent iodine, gave no protection.

Effect of noxythiolin on experimental peritonitis

The intraperitoneal instillation of noxythiolin in the treatment of peritonitis is widespread in clinical practice despite contradictory evidence as to its efficacy. In this light the value of noxythiolin was reappraised by studying its effect in guinea-pigs and mice with induced bacterial peritonitis. Treatment with a 1% solution of noxythiolin reduced the mortality rate of mice by 14% (P less than 0.1). The guinea-pig model proved unreliable giving inconsistent mortality rates throughout. Further studies are required to determine the optimum dose and concentration of noxythiolin while the search for more effective intraperitoneal antiseptics should continue.

The effect of noxytiolin in experimental peritonitis

The evidence for the value of noxytiolin (Noxyflex) in peritonitis is contradictory. In a controlled trial of the effect of noxytiolin in pertonitis in rabbits we have found a significant increase in mortality in the trial group compared with a control group, but no significant difference when a dose equivalent to the recommended human dose is used. The postoperative course is adversely affected in the animals receiving noxytiolin.