Abstract
Aim
Antibiotic prophylaxis is critical for the prevention of fracture related infection (FRI) in trauma patients, particularly those with open wounds. Administration of prophylactic antibiotics prior to arrival at the hospital (e.g. by paramedics) may reduce intraoperative bacterial load and has been recommended; however scientific evidence for pre-hospital administration is scarce.
Methods
The contaminated rabbit humeral osteotomy model of Arens was modified to resemble the sequence of events in open fractures. In an initial surgery representing the “accident”, a 2mm mid-diaphyseal hole was created in the humerus and the wound was contaminated with a clinical Staphylococcus aureus strain (mean 1.6×106 Colony Forming Units, CFU). The animals were allowed recover for 4 hours mimicking the period from trauma to debridement. At this time, a second procedure was performed in order to debride and irrigate the wound, and to fix a complete osteotomy that was made through the initial defect. Three test groups were included (n=8 rabbits per group): 1) no antibiotic therapy; 2) standard “in-hospital” antibiotic prophylaxis (24 hours therapy starting 30 minutes before surgery); 3) “pre-hospital” antibiotics (single dose 15 minutes after the “accident”). The antibiotic used was cefuroxime and was administered in a weight-adjusted dosage.
Results
In the absence of any antibiotic administration (group 1), high bacterial counts were identified at fixation (1.89×106 CFU) and at euthanasia (day 7, 7.70×107 CFU) in all rabbits. When 24 hours of antibiotics were administered commencing “in hospital” (group 2), the bacterial load during fixation surgery was slightly reduced (CFU 9.88×105) and 50% of animals were infected at euthanasia. When one single shot of antibiotics was administered in the “pre-hospital” setting (group 3), the bacterial load during fixation surgery was significantly lower than for both groups 1 and 2(CFU 2.34×103) yet all animals were infected at euthanasia.
Conclusions
Early pre-hospital administration of antibiotics significantly reduced the bacterial load in the operative field at the time of debridement compared to regular prophylaxis. However, continuation of systemic antibiotics is necessary in order to prevent infection in this model.
