The influence of lavage on peritonitis

Role of peritoneal mesothelial cells in peritonitis

Background

Peritoneal mesothelial cells have a remarkable capacity to respond to peritoneal insults. They generate an intense biological response and play an important role in the formation of adhesions. This review describes these activities and comments on their relationship to surgical drainage, peritoneal lavage and laparostomy in the management of patients with peritonitis.

Methods and results

Material was identified from previous review articles, references cited in original papers and a Medline search of the literature. The peritoneal mesothelium adapts to peritonitis by facilitating the clearance of contaminated fluid from the peritoneal cavity and inducing the formation of fibrinous adhesions that support the localization of contaminants. In addition, the fluid within the peritoneal cavity is a battleground in which effector mechanisms generated with the involvement of peritoneal mesothelial cells meet the contaminants. The result is a complex mix of cascading processes that have evolved to protect life in the absence of surgery.

Conclusion

Future advances in the management of patients with severe peritonitis may depend upon molecular strategies that modify the activity of peritoneal mesothelial cells.

Current concepts in peritonitis

Peritonitis is a serious and common infection. Its pathogenesis and microbiology have been well defined. Such risk factors as age, site of infection, physiologic response of the patient, presence of organ dysfunction, and malnutrition may influence the outcome of this disease process. The presence of antibiotic-resistant organisms and delays in operative intervention are also associated with treatment failure and higher mortality. Surgeons have the greatest impact on this disease in their ability to control the source of infection and to administer proper antimicrobial therapy.

Intensive care unit management of intra-abdominal infection

OBJECTIVE

To review the biologic characteristics of, and management approaches to, intra-abdominal infection in the critically ill patient.

DESIGN

Narrative review.

SETTING

Medline review focussed on intra-abdominal infection in the critically ill patient.

PATIENTS AND SUBJECTS

Restricted to studies involving human subjects.

INTERVENTIONS

None.

RESULTS

Intra-abdominal infections are an important cause of morbidity and mortality in the intensive care unit (ICU). Peritonitis can be classified as primary, secondary, or tertiary, the unique pathologic features reflecting the complex nature of the endogenous gut flora and the gut-associated immune system, and the alterations of these that occur in critical illness. Outcome is dependent on timely and accurate diagnosis, vigorous resuscitation and antibiotic support, and decisive implementation of optimal source control measures, specifically the drainage of abscesses and collections of infected fluid, the debridement of necrotic infected tissue, and the use of definitive measures to prevent further contamination and to restore anatomy and function.

CONCLUSIONS

Optimal management of intra-abdominal infection in the critically ill patient is based on the synthesis of evidence, an understanding of biologic principles, and clinical experience. An algorithm outlining a clinical approach to the ICU patient with complex intra-abdominal infection is presented.

Surgical site infections: epidemiology and prevention

BACKGROUND

The overall incidence of surgical site infection (SSI) has been estimated to be 2.8% in the United States, according to the U.S. Centers for Disease Control and Prevention, although the data may underrepresent the true incidence of such infections owing to inherent problems with voluntary self-reporting by surgeons of infections that occur in the ambulatory surgical setting. This review analyzes the reasons why patients are at risk and what can be done to minimize the risk.

METHODS

Review of the pertinent English-language literature.

RESULTS

Factors that contribute to the development of SSI include those that arise from the patient's health status, those that relate to the physical environment where surgical care is provided, and those that result from clinical interventions that increase the patient's inherent risk. Careful patient selection and preparation, including the judicious use of antibiotic prophylaxis, can decrease the overall risk of infection, especially following clean-contaminated and contaminated operations. However, antibiotics are not a substitute for attention to detail and meticulous surgical technique, and can increase the risk of nosocomial infection following injudicious use (that is, overuse).

CONCLUSION

Most SSIs can be attributed to risk factors inherent to the patient, rather than to inherently flawed surgical care. Nonetheless, the surgeon can minimize the risk to the patient through careful patient selection and preparation, attention to technical details and awareness of the operating room environment, and the selective use of short-duration, narrow-spectrum antibiotic prophylaxis for appropriate patients.

Granulocyte colony-stimulating factor but not peritoneal lavage increases survival rate after experimental abdominal contamination and infection

BACKGROUND

The value of peritoneal lavage for intra-abdominal contamination and infection has never been proven scientifically. In contrast, the stimulation of host defence mechanisms with cytokines such as granulocyte colony-stimulating factor (G-CSF) has appeared promising in recent clinical trials.

METHODS

Clinic modelling randomized trials (CMRTs), which model the complexity of the clinical reality, were used in rats in which peritoneal contamination and infection (PCI) was produced with human stool bacteria. The following groups were compared: trial 1, intraoperative peritoneal lavage with saline versus taurolin (18 rats per group); trial 2, no lavage versus saline lavage versus saline lavage plus subcutaneous administration of G-CSF (18 rats per group); trial 3, lavage with saline versus no lavage (30 rats per group). The primary endpoint was mortality at 120 h. Secondary endpoints were the phagocytic activity of granulocytes, and systemic and peritoneal cytokine levels.

RESULTS

In trial 1 lavage with taurolin was not superior to that with saline (five of 18 versus eight of 18 animals survived; P = 0.32). In trial 2, six of 18 animals having no lavage and three of 18 receiving saline lavage survived. The combination of lavage and G-CSF increased the number of animals surviving to 11 of 18 (P < 0.05). Lavage combined with G-CSF stimulated granulocyte phagocytic activity (P < 0.01) and reduced the levels of interleukin (IL) 6 (P < 0.01) and tumour necrosis factor alpha (P < 0.05) in peritoneal fluid, as well as plasma levels of IL-6 (P < 0.05) and IL-10 (P < 0.01). In trial 3, survival was not significantly different in animals having lavage (14 of 30) and no lavage (19 of 30) (P = 0.14).

CONCLUSION

In these CMRTs of intra-abdominal contamination and infection, peritoneal lavage was not beneficial, but when lavage was combined with subcutaneous administration of G-CSF mortality was reduced and the local and systemic cytokine response was downgraded. Results from these CMRTs were used directly to define the trial conditions of a randomized clinical trial with G-CSF. Peritoneal lavage is not recommended.

Serious intra-abdominal infections

Serious intra-abdominal infections continue to plague patients and vex surgeons and other caregivers. The mortality rate can exceed 20%, and the morbidity associated with severe cases (eg, enterocutaneous fistula, ventral hernia resulting from open-abdomen management) requires reoperation and months of convalescence. There is no consensus as to the definition of severity and a paucity of studies that focus on treatment at the severe end of the spectrum. Attempts are being made to address the adequacy of operative management (adequacy of "source control") in the context of randomized antibiotic trials. The surgical procedure is the primary treatment modality for most types of intra-abdominal infection, whereas antibiotic therapy is usually adjunctive. It remains to be determined whether the adequacy of source control can be quantified meaningfully.