Bacteremia is an invasion of the bloodstream by infectious micro-organisms. Severe bacteremia is sepsis. Release of toxins by microorganisms (i.e., gram negative bacteria) causes host macrophages to produce defense substances such as kinins, cytokines, complement and prostaglandins causing vasodilation, increased capillary permeability, leaking of plasma into tissues and a fall in blood pressure (septic shock). Disordered temperature regulation, myocardial depression and multiple organ system failures occur.
Complications are disseminated intravascular coagulation (DIC) and adult respiratory distress syndrome (ARDS). Frequent sites are the urinary tract, GI tract and lungs. Extremes of age are particularly susceptible, as are burn victims, diabetics, cancer patients and those having undergone recent invasive procedures.
The common septic patient is an elderly person with a urinary tract infection that has progressed to a systemic problem. The patient is warm and flushed, mildly agitated, and the temperature is increased (“warm shock”). This often progresses to “cold shock” from peripheral vasoconstriction and hypotension. Obtundation is often present, accompanied by hyperventilation because of metabolic acidosis. A widened pulse pressure is frequently present.
1. The ABCs of resuscitation are followed;
2. Two large bore IV’s are placed and Ringers lactate solution is infused wide open to maintain a urine output of 30 cc/h (peds: 1 cc/kg/h);
3. If the blood pressure does not improve with fluid, a pressor such as dopamine 5 ug/kg/min is added, and
4. An intravenous antibiotic relevant to the source of infection is started, such as IV ceftriaxone 1 gm + gentamycin 1.5 mg/kg (peds: ceftriaxone 50 mg/kg).