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
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.