Sepsis, Systemic Inflammatory Response Syndrome, and Multiple Organ Dysfunction Syndrome

Definition and Recognition

The systemic inflammatory response syndrome (SIRS), sepsis, and multiple organ dysfunction syndrome (MODS) are conditions that may arise in patients throughout the perioperative period. They are defined by the presence of specific signs and symptoms ( Boxes 24.1 and 24.2 ). Advances in medical care and improved therapies for patients suffering from complex medical and surgical conditions, along with a desire to facilitate categorization and comparison of patients with multiple medical morbidities, have helped the definitions of SIRS, sepsis, and MODS evolve to their current states.

SIRS criteria are general enough that some anxious preoperative patients, and virtually all postoperative patients, may meet the criteria. Its development may therefore fail to trigger a heightened level of concern for the clinician in the perioperative period. However, SIRS criteria often herald the development of the more troublesome condition of sepsis, and the considerable morbidity and mortality that it carries. As the difference between SIRS and sepsis hinges merely on the presence of infection, many patients presenting for surgery meet the criteria for sepsis. The proinflammatory nature of surgery has the potential to further progress a patient into the category of septic shock.

MODS is a dynamic process characterized by the progressive failure of multiple organ systems and may be precipitated by sepsis, trauma, or other processes. MODS is commonly observed in patients in the intensive care unit (ICU) and may be encountered in the perioperative setting when an ICU patient requires surgical intervention.

Risk Assessment and Implications

Although the physiologic parameters that define SIRS are common and may represent a heightened stress response, sepsis is a highly pathologic condition. Surgery and acute illness have a profound effect on metabolic and immunologic function and may increase a patient’s risk for developing sepsis and MODS. The body’s ability to extract and utilize oxygen is impaired in sepsis, and lactate production is increased. Endocrine abnormalities become prominent, including a reduction in vasopressin production and resistance to other hormones, including insulin and catecholamines.

Each year millions of patients experience surgical site infections, and surgical patients account for 30% of patients with sepsis. Risk factors for perioperative sepsis include the elderly population, male sex, and African American race. Early identification of patients at risk for developing sepsis and MODS may facilitate early intervention and proper triage of patients to an intensive care environment. Early and aggressive treatment of sepsis has been shown to reduce morbidity and improve survival. Anesthesiologists are in a unique and favorable position to initiate therapy for patients with SIRS and sepsis, including securing central venous access and invasive monitors, providing volume resuscitation, and administering antibiotics. For patients with MODS, diagnostic interventions such as echocardiography may be performed in the operating room or ICU, and supportive treatment initiated or continued under an anesthesiologist’s care.

Source Control

The inflammatory process that defines SIRS may be initiated by any number of insults to the body—infection, trauma, metabolic abnormality, or disease process. The patient’s history, physical examination, and laboratory or diagnostic studies are useful to identify infectious causes of continuing inflammation. Source control is a hallmark of management. Early identification and treatment of the underlying condition may prevent progression of inflammation and/or the development of sepsis or MODS. In some situations, such as surgical debridement of an infection, achieving source control may transiently worsen a patient’s clinical condition as the patient’s body reacts to the additional stress of surgery.

Supportive Care

Supportive care may be divided into different categories.