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[Gr. sēpsis, putrefaction, decay]
A systemic inflammatory response to infection, in which there is fever or hypothermia, tachycardia, tachypnea, and evidence of inadequate blood flow to internal organs.
Approximately 250,000 deaths due to sepsis occur annually in the U.S., making it the 13th leading cause of death. The number of patients with sepsis has increased significantly in the last 25 years as a result of several factors: the aging of the population; the increased number of patients living with immune-suppressing illnesses, e.g., organ transplants; the increased number of patients living with multiple diseases; and the increased use of invasive or indwelling devices in health care, which serve as portals of entry for infection.
Sepsis results from the combined effect of a virulent infection and a powerful host response to the infection, e.g., the body's release of cytokines or chemokines such as tumor necrosis factor, nitric oxide, interleukins, and others. Infections of the lungs, abdomen, and urinary tract are implicated in sepsis more often than are infections at other body sites.
The clinical syndrome of sepsis is readily recognized. The diagnostic impression based on the history and physical assessment of the patient can be supported by a variety of laboratory studies and critical care interventions.
Invasive hemodynamic monitoring in septic patients typically reveals an elevated cardiac index, decreased systemic vascular resistance, decreased oxygen delivery to tissues, and decreases in mixed venous oxygen saturation. Laboratory studies of sepsis usually reveal leukocytosis (or severe leukopenia), thrombocytopenia, elevated liver enzymes, hypocalcemia, hypoalbuminemia, and increases in the prothrombin time and serum creatinine level.
The primary objectives are rapid resuscitation of the patient, eradication of the underlying cause of infection, support of failing organ systems, and prevention of complications. Resuscitation includes maintaining an open airway; supporting ventilation; providing aggressive fluid support (esp. in the first few hr); maintaining tight control of blood sugars (glucose levels between 80 and 110 mg/dL); providing vasopressor drugs for persistent hypotension; and intensive monitoring. Eradicating the underlying infection involves administering broad-spectrum antibiotics until a precise cause is identified, removing portals of infection or infected prostheses, and draining or débriding abscesses if present. Complications in septic patients are prevented with good supportive care: antithrombotic stockings or pneumatic dressings and sometimes heparin to lessen the risk of venous thrombosis, skin care to prevent decubitus ulcers, enteral nutrition to prevent starvation, and aseptic techniques to limit secondary hospital-acquired infections.
IMPACT ON HEALTH
The syndrome is a common cause of death in critically ill patients; approx. 50% of patients with sepsis die.
Acute complications of sepsis include shock, organ failure, e.g., adult respiratory distress syndrome or acute renal failure, disseminated intravascular coagulation, altered mental status, jaundice, metastatic abscess formation, and multiple organ system failure. Survivors of sepsis may experience long-term cognitive deficits, physical disability, and internal organ malfunction.
Specimens of blood and body fluids are collected and cultured. Two or three consecutive blood cultures are obtained while the patient is febrile. The patient's symptoms and vital signs are carefully assessed, and his or her lungs are auscultated for normal and adventitious lung sounds. The patient's urine output is monitored for oliguria, and he or she is observed for any change in mental status. The patient's daily fluid intake and output and body weight also are measured and recorded.
At least one large-bore intravenous catheter is inserted, and prescribed antibiotics are administered. The patient is given information about the therapy and is assessed for desired responses and adverse effects. Antipyretics may be prescribed. Fluid and electrolyte therapy is prescribed to maintain desired balance or correct deficiencies. Oxygen is administered based on SaO2 readings, tachypnea, and tachycardia. As soon as culture results permit, the patient's antibiotic regimen is revised to use specific drugs to which the offending organism is sensitive. After doses of these drugs are given, serum antibiotic levels (trough and peak) may be monitored to prevent toxicity and ensure effectiveness. The patient is assessed carefully for signs of disseminated intravascular coagulation, adult respiratory distress syndrome, renal failure, heart failure, gastrointestinal ulcers, and hepatic abnormalities, any of which can complicate the clinical picture.
If septic shock occurs, oxygenation and perfusion are vigorously supported. An arterial catheter may be placed to measure blood pressure and provide access for arterial blood gas (ABG) samples. A pulmonary artery catheter may be used to monitor the patient's hemodynamic status. The health care team monitors closely for fluid overload. Nasoendotracheal intubation and mechanical ventilation may be necessary to overcome hypoxia, and ABGs are evaluated to determine FiO2 and ventilatory volumes. If shock persists after volume expansion, vasopressor and inotropic therapy may sometimes be prescribed to maintain adequate renal and brain perfusion. During vasopressor administration, central pressures and cardiac rate and rhythm are closely monitored. Metabolic (lactic) acidosis may sometimes be corrected with IV bicarbonate therapy. A gram-negative endotoxin vaccine may be prescribed, as may other experimental treatments to block the rapid inflammatory process (corticosteroids, opiate antagonists, prostaglandin inhibitors, and calcium channel blockers). The patient's response is assessed, and adverse reactions are noted.
A quiet, calm milieu and psychological support are provided for the critically ill patient. Oral hygiene is provided to prevent stomatitis, sordes, and salivary obstruction, esp. if the patient is permitted nothing by mouth. Nutritional needs are monitored, with consultations with the nutritional therapist to determine the need for enteral or parenteral nutrition. The patient's skin and joint function must be protected by assessing the skin and providing required care, as well as through frequent, careful repositioning, range-of-motion exercises, and correct body alignment, with supportive devices as necessary. The health care team should function as a liaison to family members, offering them emotional support and helping them to understand the patient's illness and the treatment regimen.