Obesity and Antibiotic Tissue Concentration

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00980486
Recruitment Status : Completed
First Posted : September 21, 2009
Last Update Posted : October 8, 2010
University of California, Irvine
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Brief Summary:
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.

Condition or disease

Detailed Description:

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.

Study Type : Observational
Actual Enrollment : 31 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Effects of Maternal Obesity on Tissue Concentrations of Prophylactic Antibiotics During Cesarean Delivery
Study Start Date : June 2009
Actual Primary Completion Date : June 2010
Actual Study Completion Date : June 2010

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U.S. FDA Resources

BMI <30
BMI <30
BMI 30-39
BMI 30-39
BMI >40
BMI >40

Primary Outcome Measures :
  1. To assess the effects of maternal obesity on the concentrations and adequacy of antimicrobial activity of prophylactically administered antibiotics within tissues (subcutaneous adipose and myometrial) at the time of cesarean delivery. [ Time Frame: 6 weeks ]

Secondary Outcome Measures :
  1. To assess the concentrations and adequacy of antimicrobial activity of prophylactically administered antibiotics within tissues (subcutaneous adipose and myometrial) at the time of cesarean delivery. [ Time Frame: 6 weeks ]

Biospecimen Retention:   Samples Without DNA
Adipose, myometrial and blood serum samples

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
All patients requiring cesarean delivery under non-emergent circumstances

Inclusion Criteria:

  • Patients at term (> 37 weeks) undergoing a cesarean delivery.

Exclusion Criteria:

  • Women younger than 18 years,
  • Pre-gestational diabetes,
  • Chronic hypertension,
  • Collagen vascular disease,
  • Multiple gestation,
  • Contraindications to cefazolin administration (known anaphylactic reaction to penicillins or known cephalosporin allergy),
  • Any exposure to cephalosporins in one week prior to cesarean section, OR
  • Need for emergent cesarean delivery or diagnosis of chorioamnionitis.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00980486

United States, California
Women's Pavilion at Miller Children's Hospital
Long Beach, California, United States, 90806
University of California Irvine Medical Center
Orange, California, United States, 92868
Sponsors and Collaborators
University of California, Irvine
Principal Investigator: Kenneth Chan, MD Long Beach Memorial Medical Center

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Kenneth Chan MD, Long Beach Memorial Medical Center Identifier: NCT00980486     History of Changes
Other Study ID Numbers: 587-08
First Posted: September 21, 2009    Key Record Dates
Last Update Posted: October 8, 2010
Last Verified: September 2010

Keywords provided by MemorialCare:
Antibiotic Concentration

Additional relevant MeSH terms:
Nutrition Disorders
Body Weight
Signs and Symptoms
Anti-Bacterial Agents
Antibiotics, Antitubercular
Anti-Infective Agents
Antitubercular Agents