Background: Despite the fact that wound irrigation is a common
surgical procedure, there are many variables, including delivery device,
irrigant type, and fluid volume, that have yet to be optimized. The purpose of
this study was to compare, with use of transgenic bioluminescent bacteria and
standard quantitative microbiological methods, the efficacy of pulsed lavage
and bulb syringe irrigation in reducing wound bacterial counts.
Methods: A caprine model of a complex, contaminated musculoskeletal
wound was developed with use of a bioluminescent strain of Pseudomonas
aeruginosa that can be quantified. Luminescent activity was recorded as
relative luminescent units with use of a photon-counting camera six hours
after the wound was created and inoculated. Twelve goats were randomly
assigned to either the pulsed lavage group or the bulb syringe irrigation
group. Each wound was irrigated with normal saline solution in 3-L increments
for a total of 9 L and was imaged after each 3-L increment. In addition,
quantitative culture samples were obtained from different tissues within the
wound before and after irrigation.
Results: Pulsed lavage decreased the amount of relative luminescent
units by 52%, 64%, and 70% at 3, 6, and 9 L, respectively. The bulb syringe
irrigation reduced the amount of relative luminescent units by 33%, 44%, and
51% at these same time-points. Significant differences in luminescence were
noted between the two groups after both 6 and 9 L of irrigation (p = 0.04).
The correlation coefficients between relative luminescent units and
quantitative cultures for the condition before irrigation and after irrigation
were r = 0.96 and 0.83, respectively.
Conclusions: Pulsed lavage was more effective than bulb syringe
irrigation in reducing bacterial luminescence after both 6 and 9 L of
irrigation. Both device and volume effects can be demonstrated with use of
this model. Bioluminescent bacteria provide a method to visualize bacterial
distribution and to quantify the bacteria in a wound.
Clinical Relevance: Pulsed lavage is a more effective and efficient
method of irrigation to remove bacteria in a complex musculoskeletal wound. In
the model we used, pulsed lavage irrigation with 3 L of saline solution
resulted in a reduction of approximately the same amount of bacteria as did
irrigation with 9 L with use of a bulb syringe.