Early wound irrigation improves the ability to remove bacteria

Background: Although most surgeons prefer to treat contaminated wounds as soon as possible, the effect of timing on the ability of irrigation to reduce the amount of bacteria in a wound is not fully known. We evaluated the effect of different delays in irrigation on bacterial removal in an animal model. Methods: A complex musculoskeletal wound was created in the proximal part of the leg of goats. The wound was contaminated with Pseudomonas aeruginosa (lux) bacteria, genetically modified to emit photons, in order to allow for quantitative analysis of bacterial concentration with a photon-counting camera system. The contaminated wounds were closed, and wound irrigation was performed with 6 L of normal saline solution by means of pulsatile lavage after the assigned time-intervals of three, six, and twelve hours. Images were made before and after treatment. Relative luminescent units and clearance ratios were obtained and calculated for each wound. Results: Earlier wound irrigation resulted in superior bacterial removal in our model. Irrigation resulted in a 70% ± 2%, 52% ± 3%, and 37% ± 4% reduction in bacterial counts from the pre-irrigation level at three, six, and twelve hours, respectively. The clearance ratios were significantly different at all time-points (p < 0.004). Conclusions: Earlier irrigation in our contaminated wound model resulted in superior bacterial removal. Clinical Relevance: While the actual bacterial counts necessary to establish a wound infection in humans is unknown, early irrigation of the contaminated wound is recommended for the prevention of infection.