The role of surgery in the management of septic shock—intra-abdominal causes of sepsis

AORN Journal,  Feb, 2007  by George H. Sakorafas,  Adelais G. Tsiotou,  Maria Pananaki,  George Peros

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Source control is of utmost importance in the management of septic shock. When sepsis is a result of a surgical disease (ie, a disease treated by surgery), source control can be achieved by performing either an open or a minimally invasive surgical procedure. This article reviews the most common intra-abdominal pathological sources of sepsis, diagnostic methods, and therapeutic options.

INTRA-ABDOMINAL SOURCES OF SEPSIS

Numerous conditions can be sources of infection in patients who have sepsis. Many surgical diseases may cause intra-abdominal sepsis, including intra-abdominal abscesses; severe acute necrotizing pancreatitis; fulminant acute pancreatitis, and some common diseases that have taken a complicated turn (eg, acute gallstone disease, acute appendicitis).

INTRA-ABDOMINAL ABSCESSES. An intra-abdominal abscess is a collection of pus accumulated in a cavity within the abdomen after a severe infectious process that has affected an intra-abdominal organ. To accurately and reliably diagnose an intra-abdominal abscess, the physician should use imaging methods, such as ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI).

SEVERE ACUTE NECROTIZING PANCREATITIS. Acute, necrotizing pancreatitis occurs when the pancreatic parenchyma or peripancreatic tissues become necrotic. Approximately 80% of the cases are mild and respond well to conservative management, usually within three to five days. (1-3) Approximately 20% of cases are severe. (1-4)

The natural course of acute, necrotizing pancreatitis has two phases. The first phase occurs during the first two weeks after the onset of pancreatitis and is characterized by systemic inflammatory response syndrome (SIRS). In this precocious phase of acute pancreatitis, SIRS may be observed without the presence of pancreatic necrosis and often is observed in the absence of superinfection (ie, a second or subsequent infection by the same microorganism or by a different organism). (1)

The second phase is characterized by the appearance of superinfection of the necrotic pancreatic parenchyma. This phase usually is observed after the first two weeks of the onset of the disease. The risk of superinfection increases with the extent of necrosis of the pancreatic parenchyma and peripancreatic tissues. (3)

FULMINANT ACUTE PANCREATITIS. Fulminant acute pancreatitis, a form of severe acute necrotizing pancreatitis, is characterized by rapidly evolving, multiple-organ failure within the first few days of disease onset. It is associated with increased mortality and a poor prognosis despite intensive supportive management and surgical intervention. (4,5)

OTHER CAUSES. Some common diseases that take a complicated turn also can cause intra-abdominal sepsis. Examples include gallstone disease (eg, acute cholangitis, acute cholecystitis); acute appendicitis; acute diverticulitis; and abdominal catastrophes such as intestinal necrosis after acute mesenteric ischemia.

DIAGNOSTIC METHODS

The findings of a clinical examination remain important in diagnostically evaluating a patient who has sepsis; however, in critically ill patients, physical examination is not always reliable for many reasons (eg, decreased levels of consciousness as a result of medications, severe underlying disease), particularly if the patient is being mechanically ventilated. Early diagnosis and management of intra-abdominal pathological entities in a critically ill, septic patients remain a challenge for physicians. (6,7) To minimize the increased mortality that is caused by delaying surgical intervention, repeated examinations of the patient are required, and the index of suspicion about the possibility of the presence of serious intra-abdominal surgical disease should be increased. In a recent study by Gajik et al, (7) approximately 95% of patients with acute abdomen who were hospitalized in the intensive care unit (ICU) showed some abdominal tenderness on physical examination. Nevertheless, only 38% showed peritoneal signs, and in this study, the absence of peritoneal signs resulted in delayed surgical evaluation.

Unreliability of the clinical examination in critically ill patients with sepsis explains why the decision to perform surgery should be based on other diagnostic procedures. A surgeon should examine the patient early in the course of the disease and order appropriate imaging studies. (8) Useful diagnostic tools for patients with a possible intra-abdominal source of sepsis include

* abdominal ultrasonography,

* abdominal CT,

* abdominal paracentesis,

* diagnostic peritoneal lavage (DPL), and

* diagnostic laparoscopy.

ABDOMINAL ULTRASONOGRAPHY. Abdominal ultrasonography is a valuable diagnostic tool because it is more sensitive than CT for patients with gallbladder diseases (eg, cholelithiasis, cholecystitis), and it remains an important tool for initial diagnostic evaluation of a patient with sepsis. A particular advantage of ultrasonography is that it can be performed in the ICU, thereby obviating the need to transport a critically ill patient outside the ICU (ie, to radiology, CT, or MRI). Another advantage of ultrasonography is that a well-trained radiologist can convert the imaging procedure from diagnostic to therapeutic by performing a percutaneous drainage of an abscess under ultrasonographic guidance. The usefulness of ultrasonography in diagnostically evaluating critically ill patients who are septic remains relatively restricted, however, because of the limitations of ultrasonography. (9) Some of the significant disadvantages of ultrasonography include variability of operator interpretation and inability to diagnose pathology in the presence of a significant amount of gas in the intestinal lumen, external dressings, or drains. (10,11)