R C Bone

The sepsis syndrome represents a systemic response to infection and is defined as hypothermia (temperature less than 96 degrees F) or hyperthermia (greater than 101 degrees F), tachycardia (greater than 90 beat/min), tachypnea (greater than 20 breath/min), clinical evidence of an infection site and with at least one end-organ demonstrating inadequate perfusion or dysfunction expressed as poor or altered cerebral function, hypoxemia (PaO2 less than 75 torr), elevated plasma lactate, or oliguria (urine output less than 30 ml/h or 0.5 ml/kg body weight.h without corrective therapy). One hundred ninety-one patients with the sepsis syndrome were evaluated prospectively and comprised the placebo group of a multicenter trial of methylprednisolone in sepsis syndrome and septic shock. Forty-five percent of the patients were found to be bacteremic. Thirty-six percent of the patients were in septic shock (sepsis syndrome plus a systolic BP less than 90 mm Hg or a decrease from baseline in systolic BP greater than 40 mm Hg) on study entry. An additional 23% of the patients developed shock after admission with 70% doing so within 24 h of study entry. Shock reversal occurred with a 73% frequency. Twenty-five percent of the patients developed the adult respiratory distress syndrome (ARDS). Mortality for the patients with sepsis syndrome who did not develop shock was 13%. Mortality for the groups of patients with shock on admission and shock postadmission was 27.5% and 43.2%, respectively. Forty-seven percent of the bacteremic patients developed shock after study admission compared to 29.6% of the nonbacteremic patients (p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Gram-negative sepsis is an increasingly common problem, with up to 300,000 cases occurring each year in the United States alone. Despite the ongoing development of new antibiotics, mortality from gram-negative sepsis remains unacceptably high. To stimulate earlier therapeutic intervention by physicians, a new set of broad definitions has been proposed to define the systemic inflammatory response characteristic of sepsis. In this review, the signs and symptoms of this progressive, injurious process are reviewed and its management is discussed, as are the mechanisms by which bacterial endotoxin triggers the biochemical events that lead to such serious complications as shock, adult respiratory distress syndrome, and disseminated intravascular coagulation. These events often occur even when appropriate antimicrobial therapy has been instituted. An increased understanding of the structure of endotoxin and its role in the development of sepsis, together with advances in hybridoma technology, has led to the development of monoclonal antibodies that bind to endotoxin and significantly attenuate its adverse effects. These agents promise to substantially reduce the morbidity and mortality associated with gram-negative sepsis.

The participation of prostaglandins in the physiologic alterations of endotoxin shock has been well established with the aid of prostaglandin synthetase inhibitors. Our study was designed to investigate the potential of ibuprofen, a highly specific cyclooxygenase inhibitor, to reverse the hemodynamic and acid base abnormalities of canine endotoxin shock. Mean blood pressure fell to 49.8 +/- 6.6 mm Hg in dogs given endotoxin by 5 min after injection, and remained below 83 mm Hg for the duration of the 120-min observation period. In animals given endotoxin followed by ibuprofen, a similar initial drop of systemic blood pressure was seen, but it subsequently recovered to 150.2 +/- 4.1 mm Hg by 120 min (P less than 0.001). Cardiac index increased in animals given ibuprofen (2.3 +/- 0.28 liter/m2 per min) compared with animals given endotoxin alone (1.0 +/- 0.09 liter/m2 per min) by termination of the experiment. The arterial pH dropped in endotoxin treated animals to 7.18 +/- 0.03 by 120 min. Ibuprofen prevented the acidosis, the final pH in ibuprofen and endotoxin treated animals measuring 7.36 +/- 0.01. We conclude that ibuprofen protects against the hypotension, acidosis, and depression of cardiac index of canine endotoxin shock.

Widespread intravascular coagulation is common in patients with sepsis. Coagulation abnormalities may result from exposure to endotoxin, from tumor necrosis factor alpha or interleukin 1 release, or from the actions of a more specific mediator, such as vascular permeability factor. The result is marked activation of the contact and coagulation systems; simultaneously, there is decreased fibrinolysis and depressed levels of the inhibitors of the contact and coagulation systems. Multiple agents are being studied to correct these abnormalities. Antithrombin III holds promise because it inhibits a number of factors important in contact and coagulation activation, not just thrombin. Plasminogen activators may prove helpful in increasing fibrinolysis during sepsis; because they have been associated with rebound thrombin generation, however, plasminogen activators may be most effective if used in conjunction with hirudin or a synthetic hirudin analogue. Bradykinin may offset hypotension in sepsis. Protein C may inhibit thrombin formation and also complex with plasminogen activator inhibitor 1, thereby promoting fibrinolysis. Other agents that may prove effective include alpha 1-antitrypsin Pittsburgh, C1-esterase inhibitor, monoclonal antibodies to contact factors, soybean trypsin inhibitors, thrombomodulin, prostaglandin I2, and aprotinin. There are no data to support the use of heparin or fibronectin, except in limited circumstances.