The purpose of this study is to determine whether the dose of prophylactic antibiotics at
the time of cesarean delivery requires adjustment in obese and overweight patients in
order to achieve optimal antimicrobial activity.

Obesity and Antibiotic Tissue Concentration

Obesity

The majority of information regarding pharmacokinetics and pharmacodynamics (the action,
properties and elimination of a drug in the body) of antibiotics is based on measurements
of the serum and plasma concentrations. Current guidelines for surgical antibiotic
prophylaxis have clearly demonstrated appropriate therapeutic levels within blood and
serum levels, resulting in low incidence of postoperative bacteremia (bacteria in the
blood) and sepsis (infection). Despite this, surgical site infections (SSI) remain the
most common postoperative complication, affecting up to 20% of patients undergoing
intra-abdominal surgery. Inadequate antibiotic penetration into the tissues of the
surgical site, in spite of therapeutic serum levels, results in an environment that is
susceptible to pathogens and subsequent infections. Antimicrobial tissue levels are
influenced by volume of distribution, regional blood flow and biological properties of
tissue. The ability of any drug to reach the tissue of interest is dictated by the
relative amount of blood flow to that organ. While lungs and kidneys enjoy a robust blood
supply, subcutaneous adipose tissue (fat) (the most frequent site of surgical site
infections) receives a small fraction of the cardiac output. Obesity creates an increased
volume of distribution, thereby resulting in a greater dilution of antibiotics when
compared to non-obese subjects. Moreover, this change in volume of distribution is
achieved primarily by increasing the relative amount of poorly perfused adipose tissue.
Therefore, it should come as no surprise that obesity is a significant risk factor for
surgical site infections.

The rate of obesity in the United States has shown a steady increase and more than
doubled in the last twenty-five years from 15% in 1980 to 32.9% in 2004. Moreover, nearly
one third of women of reproductive age are obese and approximately 6% are extremely
obese. In addition to the usual health related concerns, obesity significantly increases
the rate of complications associated with pregnancy. In particular, several studies have
demonstrated an increased incidence of cesarean delivery associated to maternal obesity.
Cesarean delivery rates, much like obesity rates, have witnessed a tremendous surge in
the last few decades and now account for approximately 30% of all deliveries or nearly
1.2 million procedures. Surgical site infections associated with cesarean delivery
include wound infections and endomyometritis (infection in the uterus), with rates
ranging from 7% to 20% depending on the demographic and obstetric variables. Despite
these alarming trends there is a paucity of data regarding antimicrobial activity of
prophylactic antibiotics in tissues and the effects of maternal obesity on these
concentrations at the time of cesarean delivery.

While the rates of cesarean deliveries have reached a plateau at around 30% in recent
years, the rates of obesity continue to climb unabated. As the attributes of the
population evolve over the course of time so must the guidelines and management adapt to
the individuals in our care.

Obesity and Antibiotic Tissue Concentration

About this trial

Study ID

Status

Type

Placebo

Accepting

Trial Timing

What is this trial about?

What are the participation requirements?

Locations

Location

Status