Prophylactic Antibiotics in Obstetrics and Gynecology: A Current Benefit; A Future Curse? William J. Ledger, MD
Wound Classification Guidelines of Surgical Wounds Provided by the American College of Surgeons Clean Clean-contaminated Contaminated Dirty and infected No endogenous bacterial contamination Vagina entered Gross spillage from gastrointestinal tract Acute bacterial inflammation encountered, without pus
Traditional Infection Rates Following Operation 1. Clean Less than 2% 2. Clean-contaminated 5-15% 5 3. Contaminated 15-30% 4. Dirty 30%
New Method Risk Index Score Range 0-30 Risk Factors 1. A patient with an American Society of Anesthesiologists pre-operative assessment score of 3, 4 or 5. 2. An operation classified as contaminated or dirty infected 3. An operation lasting over T hours. Cesarean section T is one hour Abdominal or vaginal hysterectomy T is two hours
Surgical Wound Infection Rates Score 0 1.5% Score 1 2.9% Score 2 6.8% Score 3 13%
Risk Factors: Pre-operative 1. Pre-operative stay 2. Pre-operative shave 3. Length of operation 4. Abdominal drains 5. Presence of remote infections 6. Bacterial vaginosis
Risk Factor for Infection Following Cesarean Section 1. Clinic service 2. Labor
Risk Factors for Cesarean Section Vietnam Study 1. Remote infection site 2. Chorioamnionitis 3. Severe maternal systemic disease 4. Pre-eclampsia eclampsia 5. Higher body mass index 6. Nulliparity 7. Increased intra-operative blood loss
Operative Care Cesarean Section 1. Close all subcutaneous tissue in obese patients. Fewer wound disruptions 2. Allow placenta to deliver spontaneously 3. Labor a factor 4. Subcuticular closure
Two Studies from New England Journal of Medicine 1957 and 1966 Conclusions 1. Didn t t Work. 2. Caused More Serious Problems.
Patient Pneumonia Skin Infection Antibiotic Prophylaxis 32 14 (43.8%) 8 (25%) No Prophylaxis 30 6 (20%) 0 (0%) Urinary Tract Prophylaxis 10 0 (0%) 0 (0%)
1966 Prophylactic Antibiotics in Patients Undergoing Major Operations on General Surgery Service 70 Patients placebo 65 Patients 2.0 grams methicillin & 0.5 grams chloramphenicol Three doses 1. 1-22 hrs before operations intramuscularly 2. Intravenously during the operation 3. Intravenously 2 hrs after the operations Results no benefit to prophylaxis Problems only 33 had bowel or pancreatic operations Choice of antibiotics
NEJM Bias: Didn t t Work Despite the Fact that Two Studies Prior to the 1966 Article Showed Prophylactic Antibiotics Could Play a Role in the Operating Room (1961 and 1964)
1961 Study John Burke
1964 Surgical Study Number of Patients Infection Rate Prophylactic Antibiotics 66 8% Placebo 79 27% Problem: Three Antibiotics Used for Prophylaxis
1969 Hiram Polk Studied 199 patients having elective operations on the astrointestinal tract. Biliary tract operations with a low incidence of infection were excluded 101 Cephaloridine 98 Placebo 3 Doses intramuscularly 1. On call to the operating room 2. 5 hours later 3. 12 hours later Cephaloridine significantly reduced the incidence of post-operative operative abdominal wound and intra-abdominal abdominal infections
1973: Mechanical Cleaning of Bowel Plus Oral Neomycin and Erythromycin Base Significantly reduced the rate of infection
Guidelines 1. Post-operative operative infection at operative site creates either short-term term or long-term problems.
2. The operation should be associated with endogenous bacterial contamination. Special Cases: a. Pelvic Malignancy b. Pregnancy Termination
3. The prophylactic antibiotic should have laboratory evidence of effectiveness against some of the contaminating microorganisms.
4. There should be clinical evidence of effectiveness.
VAGINAL HYSTERECTOMY
ABDOMINAL HYSTERECTOMY Most Studies Show Effectiveness, But
Abdominal Hysterectomy Moxalactam Cefazolin Control N = 50 N = 50 N = 50 Total Infections 16% 16% 16% Vaginal Cuff 8% 6% 4%
Cesarean Section In Labor
Post-operative operative Infections Endomyometritis Associated Bacteremia Associated Abdominal Wound Infection Associated Urinary Tract Infections Abdominal Wound Infection Respiratory Infection Septic Pelvic Thrombophlebitis Total Cefoxitin 10 (1) (0) (0) 1 0 1 12 (24%) Placebo 30 (8) (3) (4) 1 1 0 32 (64%)
Incidence of Endomyometritis following prophylaxis with Ampicillin/Sulbactam, Cefazolin, or Cefotetan tudy Arm N Incidence of Postpartum Endomyometritis #(%) Side Effects # mpicillin/sulbactam 95 7 (7.38%) 1 efazolin 98 14 (14.26%) 0 efotetan 99 11 (11.1%) 2
Radical Hysterectomy
Pregnancy Termination Asymptomatic Chlamydia trachomatis culture positive
Genital Tract Manipulation 1. Hysterosalpingogram 2. Intrauterine Device Insertion
Cesarean Section Not in Labor
5. The prophylactic antibiotic should be present in the surgical wound sometime during the procedure.
Special Considerations 1. Intramuscular versus Intravenous 2. Operation Lasting Longer Than Three Hours 3. Cesarean Section
6. A short course of prophylaxis should be employed.
Length of Treatment Cesarean Section Cefazolin prophylaxis & Cephalosporin treatment Significantly higher incidence of wound infection Ampicillin prophylaxis Higher incidence of Gram negative aerobic rods colonization
Exceptions 1. Asymptomatic Patient: Test Positive for Chlamydia trachomatis 2. Pregnancy Termination 3. Hysterosalpingogram 4. Intrauterine Device Insertion
7. First line antibiotics should not be used for prophylaxis.
0.0007 0.0007 91.6 91.6 142 142 8.4 8.4 13 13 4gm 4gm Piperacillin Piperacillin 0.03 0.03 87.2 87.2 129 129 12.8 12.8 19 19 2gm 2gm Ampicillin Ampicillin NS NS 84.9 84.9 124 124 15.1 15.1 22 22 1gm 1gm Cefonicid Cefonicid NS NS 82.1 82.1 119 119 17.9 17.9 26 26 1gm 1gm Ceftizoxime Ceftizoxime 0.0001 0.0001 93.9 93.9 139 139 6.1 6.1 9 1gm 1gm Cefonicid Cefonicid NS NS 83.3 83.3 135 135 16.7 16.7 27 27 2gm 2gm Cefoxitin Cefoxitin NS NS 89.5 89.5 133 133 15.5 15.5 24 24 1gm 1gm Cefoxitin Cefoxitin 0.005 0.005 89.4 89.4 144 144 10.6 10.6 17 17 2gm 2gm Cefazolin Cefazolin NS NS 79.7 79.7 173 173 20.3 20.3 44 44 1gm 1gm Cefazolin Cefazolin 77.5 77.5 110 110 22.5 22.5 32 32 1gmx3 1gmx3 Cefazolin Cefazolin P Value Value % N % N Dose Dose Antibiotic Antibiotic No Infection No Infection Infection Infection
8. The benefits should outweigh the risks.
Results with Prophylaxis Operation Unequivocal Success Procedures Vaginal Hysterectomy Hysterosalpingogram Cesarean Section: Intrauterine Device Insertion Patient in Labor Radical Hysterectomy Pregnancy Termination Abdominal Hysterectomy Value Questioned Cesarean Section - Membranes Intact, Not in Labor Laparoscopy-Assisted Vaginal Hysterectomy: No Data
The Flies in the Ointment A Future Curse?
The Centers for Disease Control (CDC) Guidelines for the Prevention of Perinatal Group B Streptococcus Disease First Published: 1996
I opposed the publication of these guidelines. Why?
1. Guidelines for clinical care should be based upon prospective clinical trials. These were not done.
Next Reiterations 1. Only Culture-Based Strategy 2. No Prophylaxis: Cesarean Section, Membranes Intact, Not in Labor.
2. It inhibits any future clinical trials only comparison has been risk- based vs. culture screening at 35-37 weeks gestation. a. Intrapartum Douching Trial Alabama. b. Timing of Prophylactic Antibiotic Administration in C-Section. C
3. It becomes the basis for malpractice judgments against Obstetricians. There is no protocol that will prevent all cases of early onset perinatal Group B sepsis, and to date the current protocols have not changed the incidence of late onset perinatal Group B sepsis.
4. We are creating problems for the future. As a result of these guidelines, over 1,000,000 mothers-to to-be a year will be receiving antibiotics in labor.
Mothers and Infants Higher rates of infant thrush and maternal breast Candidiasis in intrapartum antibiotic-exposed mothers
Mothers: Prolonged ampicillin administration increases the colonization with Gram negative aerobes.
Newborns: Rates of early onset newborn sepsis in very low birth rate babies (401-1500 1500 grams). NEJM 2002; 347:240-247 247
Before Guidelines (1991-1993) 1993) After Guidelines (1998-2000) Statistical Difference Study Patients 7,606 5,447 Group B Sepsis 5.9/1000 1.7/1000 p = <0.001 E. Coli Sepsis 3.2/1000 6.8/1000 p = <0.004
The overall rate of early onset sepsis was not significantly changed.
Prophylactic Antibiotics in Obstetrics and Gynecology William J. Ledger, MD