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CHAPTER 113: The Acute Abdomen and Intra-abdominal Sepsis 1081

had a 64% mortality rate, compared to patients not requiring such treat- The mortality rate of generalized peritonitis is about 30%. Risk factors
ment, of whom 11% died. The need for mechanical ventilation may be include age, preexisting disease, severity of physiologic derangement at
a marker of severity of illness, and poor prognosis. Source control is an the time of diagnosis, steroid dependency, and peritonitis occurring in
important mainstay of treatment for patients with secondary peritonitis. the postoperative period. The cause of death is usually uncontrolled
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There are a number of predictors for failure of source control, including sepsis with multiple organ failure. Of our 107 ICU patients with perito-
delay in intervention, APACHE >15, increased age, organ dysfunction, nitis, 68 died, with abdominal infection the main cause in over half, and
poor nutritional status, extent of peritonitis, inadequate drainage or only 7 patients dying from a cause unrelated to infection. 21
source control, and presence of malignancy. 8 Enteral nutrition is an adjunct to therapy for the ICU patient intended
to attenuate the metabolic response to stress, to prevent oxidative
Pathophysiology and Treatment: Generalized peritonitis is caused cellular injury, and to favorably modulate the immune response.
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usually by bowel perforation or infarction. Occasionally, generalized Enteral nutrition should consist of micro- and macronutrient delivery
bacterial peritonitis results from perforation of an infected gallblad- and glycemic control. Enteral nutrition is a strategy to decrease disease
der, infected pancreatic pseudocyst, or other rare disease. We shall severity, complications, and decrease length of stay in the ICU. 25
restrict our attention in this chapter to the majority of cases that are
due to gastrointestinal tract perforation. The Intensivist’s Role The intensivist should support the patient’s vital func-
Patients with generalized peritonitis become very ill because of the tions, manage complications, and anticipate indications for surgical
large surface area of the peritoneal cavity which permits massive fluid reintervention. Close collaboration between the intensivist and the
sequestration and rapid absorption of bacteria, endotoxin, and inflam- surgeon is essential. Supportive treatment includes hemodynamic, respi-
matory mediators into the systemic circulation. The hemodynamic ratory, and nutritional support and antibiotics. Complications include
effects resemble those of a large body surface burn. adverse effects of both the underlying infection, comorbid conditions
Treatment of this disease is well established. 20-24 Following rapid fluid and interventions to treat them. Table 113-4 lists complications of surgi-
resuscitation and the initiation of antibiotic therapy, patients undergo cal management.
abdominal exploration to close, resect, or externalize the perforation These patients must be examined daily by the intensivist and the
and remove contaminants and inflammatory exudates. Broad-spectrum surgeon. First, dressings covering the abdomen should be removed
antibiotics intended to eliminate residual bacteria target a broad spec- and the wound examined. The skin incision is often packed open at
trum of bacteria: gram-negative and gram-positive aerobic, facultative, operation to minimize the incidence of wound infection. 26,27 Fascial
and anaerobic bacilli and cocci. 20,22 Single agents such as carbapenems dehiscence is most common on postoperative days 4 to 8 but may
and β-lactam/β-lactamases, and combinations such as third-generation present at any time, heralded by drainage of serosanguineous fluid
cephalosporin or a quinolone plus an anti-anaerobe agent are appropri- through the fascia or incision. Diagnosis is confirmed by wound
ate regimens. They face limitations of adverse effects, antibiotic resis- examination including inspection for intra-abdominal contents. The
tance in patients and patient populations, and in serving only as adjuncts presence of loops of bowel in the wound usually means impending
evisceration. In some patients with particularly severe peritonitis, it is
to source control. 22,23 https://kat.cr/user/tahir99/
The administration of broad-spectrum antibiotics may promote not technically possible to reapproximate the fascial edges at the end
superinfections with fungi and Clostridium difficile, and the selection of of the surgical procedure. The surgeon then sutures an artificial mesh
multiple resistant microorganisms. Antibiotics should be discontinued as
soon as an acute episode of abdominal infection has subsided, preferably
after no more than 4 to 7 days. 8,11-12 Longer course antibiotic therapy is TABLE 113-4 Postoperative Complications of Surgical Treatment of Peritonitis
not associated with improved outcomes; signs of persistent abdominal
infection after a week of antibiotics should prompt a diagnostic search for Wound complications
drainable focus in the abdomen and a treatable infection extraperitone- Wound infection
ally, not just added or different antibiotics. Nonspecific signs of infection, Necrotizing soft tissue infection
such as fever, should not prompt antibiotic therapy without an anatomical
diagnosis and evidence-informed treatment plan. Nosocomial pneumo- Fascial dehiscence/evisceration
nia complicating intra-abdominal infection is highly lethal. The pos- Gastrointestinal tract complications
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sible anatomic sites of bacterial infection appear in Table 113-3. Paralytic ileus
Mechanical obstruction
TABLE 113-3 Anatomic Sites of Bacterial infection in Postoperative Patients Enterocutaneous fistula
Intra-abdominal Gastrointestinal bleeding
Peritoneal fluid Anastomotic disruption or perforation
Peritoneal fibrin Ischemic bowel
Extraperitoneal tissues (eg, hepatic macrophages) Antibiotic-associated colitis
Visceral abscess Complications arising in the peritoneal cavity
Within the gastrointestinal tract lumen (bacterial translocation, Clostridium difficile colitis) Abscess
Infected prosthetic vascular graft Recurrent peritonitis
Acalculous cholecystitis Hemorrhage
Extra-abdominal Compartment syndrome
Soft tissue infection Miscellaneous
Pneumonia Postoperative pancreatitis
Urosepsis Septicemia
Intravascular catheter infection Acalculous cholecystitis
Disseminated candidiasis Extra-abdominal

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