Sepsis is a heterogeneous clinical syndrome that can be caused
by any class of microorganism. Although gram-negative and gram-positive
bacteria account for most sepsis cases, fungi, mycobacteria, rickettsiae,
viruses, and protozoans can cause similar presentations. Microbial
blood invasion is not essential to the development of sepsis.
The incidence of severe sepsis in the U.S. is 3.0 cases per 1000
population and 2.26 cases per 100 hospital discharges; 51.1% of
patients with severe sepsis receive intensive care and an additional
17.3% undergo artificial ventilation in an intermediate
care unit or are cared for in a coronary care unit.1 Incidence
of sepsis increases >100-fold with age (0.2 per 1000 in children
age 10–14 years to 26.2 per 1000 in those >85 years of
age).1 Mortality is 28.6%, or 215,000
deaths nationally, and also increases with age, from 10% in
children to 38.4% in those >85 years of age. Women have
lower age-specific incidence and mortality, but this difference
in mortality can be explained by differences in underlying disease
and the site of infection. The average cost per case is $22,100,
with annual costs reaching $16.7 billion nationally.1 The
incidence is projected to increase by 1.5% per annum.
The incidence of sepsis and the number of sepsis-related deaths
is increasing, although the overall mortality rate among patients
with sepsis is declining.2 Sepsis is more common
among men and among nonwhite persons. The rate of sepsis due to
fungal organisms has increased by 207%, and since 1987
gram-positive bacteria have become the predominant pathogens.2 Organ
failure contributes cumulatively to mortality; survival is improved
among patients with fewer than three failing organs. The average
length of hospital stay has increased, and the rate of discharge
to non–acute care medical facilities has increased. Elderly
patients are more likely to develop infections due to gram-negative
organisms than are younger patients. Elderly patients are more likely
than younger patients to have sepsis due to respiratory or GU tract
infections. Pneumonia is the single most common cause of sepsis
in the elderly.
Approximately 0.7% of ED patients present with suspected
severe sepsis; more than two thirds of sepsis patients present initially
to the ED.3 Over half of ED sepsis patients are
≥65 years of age. Approximately 17% of the presenting patients
reside in nursing homes. One half of these patients arrive by ambulance,
and mean length of stay in the ED is approximately 4.7 hours.
In the U.S. there are 42,364 cases of pediatric sepsis each year,
or 0.56 cases per 1000 population per year.4 The
incidence is highest in infants (5.16 per 1000), falls dramatically
in older children (0.20 per 1000 in 10- to 14-year-olds), and is
15% higher in boys than in girls (0.60 vs. 0.52 per 1000, p <.001).
Hospital mortality is 10.3%, or 4383 deaths nationally
(6.2 per 100,000 population). Half of pediatric patients have underlying
disease (49.0%), and over one fifth (22.9%) are
low-birth-weight newborns. Respiratory infections (37%)
and primary bacteremia (25%) are the most common infections.
The mean length of stay for pediatric patients is 31 days and average
cost per case is $40,600. Estimated annual total costs are $1.97
Definitions of sepsis are regularly updated and now include definitions for
pediatric cases5–8 (Table
146-1). The definitions provide a conceptual ...