Antibiotic prophylaxis at caesarean section – guidelines and clinical practice – an evaluation using data from the Norwegian surveillance system for surgical site infections

Background:  In many interventions prophylactic antibiotics reduce surgical site infections (SSI) and evidence-based international guidelines (Cochrane reviews) recommend their administration prior to surgical incision.  The Norwegian association of Gynecology and Obstetrics recommends prophylactic use of antibiotics for all acute cesarean sections (CS), and in elective sections of long duration and/or excessive bleeding. There is no recommendation on timing.
Objective: Through data from the Medical Birth Registry, Norway (MBR), and data from the Norwegian Surveillance system for surgical site infections (NOIS), we will explore completeness of reporting, compliance with guidelines and the effect of prophylactic antibiotics on SSIs in women having CS.
Methods: NOIS was implemented by law in 2005.  All hospitals have to report at least one of five major surgeries (coronary-by-pass, cesarean section, hip replacement surgery, cholecystectomy, and appendectomy) through active post-discharge surveillance (PDS) of 30 days.  CDC definitions of infectious outcomes are applied.  Mandatory surveillance period is September 1^st through November 30^th on annual basis. Data harvesting are mainly computerized applying existing data modules in the hospitals’ administrative systems, whereas PDS are done on manual basis.
Results:  Out of 45 hospitals performing CS in Norway, the number of hospitals reporting on CS to NOIS increased from 20 in 2005 to 37 hospitals in 2008, representing 43% and 85% of the national volume of surgery, respectively. Completeness of 25 days PDS varied between 86% (2008) to 91% (2006). Prophylactic antibiotics were applied in nearly 30% and 78% of elective and acute CS, respectively.  Over the 4-year study period surgical site infections remained stable with an incidence of 6% for wound infections, and 1-2% incidence of organ/space infections.  There were no major differences in incidence of SSI among women having elective and acute surgery by prophylactic antibiotic use (inconsistent results over study period). Most wound infections were diagnosed after discharge (>80%), whereas more deep organ/space infections were diagnosed during hospital stay (>60%).
Conclusions:   The implementation of a new surveillance system for SSI was well accepted, and by practice more hospitals report SSI from several procedures.  Completeness of reporting is considered high, and we are pleased with the compliance on active 30-days PDS.  Infection rates remain low with no major difference in elective/acute surgery by use of prophylactic antibiotics.