Evaluation of three techniques for cleaning infected surgical site with physiological serum

Abstract

International literature reports many studies on cleaning of wounds. In Brazil, this type of study is not common. From international studies, the irrigation wound cleaning technique with 19 Gauges (G) needle  and 35 ml syringe, causing a pressure of 4 to 8 " psi", is considered to be ideal for the cleaning procedure. In Brazil, however, there is no standardization of this material (35ml syringe and 19G needle) and adaptations are required. This research was designed with the purpose to compare the reduction of microorganisms in infected wounds under the treatment with saline solution and the application of three different techniques: traditional mechanical removal, irrigation with 25 x 8 needles (21G) and 20 ml syringe, and irrigation with 40 x 12 (18G) needle and 20 ml syringe. Three groups of infected wounds in patients from the Regional University Hospital of Northern Paraná (HURNP) were studied, divided according to the cleaning technique to be applied in the lesion. It is worth mentioning that the first technique to be applied was chosen at random and the other two were interposed. Cultures were collected from group I (mechanical removal) and group II (20ml syringe and 40 x 12mm needle) at first and secondly from group III (20ml syringe and 25 x 18 needle). The cultures were collected by means of swabs before and after the cleaning with physiological serum and application of one of the techniques mentioned above. All the material collected was sent to the Laboratory of Microbiology of the HURNP, where a technique for quantitative microbiological analyses with swabs was developed in order to allow for the comparison of numbers of bacteria both before and after the cleaning procedure. A Faculty member from the Londrina State University Department of Physics collaborated in this study undertaking the experiments which could provide the pressure value the set of syringe and needle had on the sprays of saline solution during the irrigation of the wound. The results were amazing as the experiments proved that with a 20ml syringe and an 18G needle we can have a 9.5 "psi" pressure and with a 21G needle a 13.5 "psi" pressure. Although the pressures are within the range of values considered adequate by the literature (4-15 “psi”), there was no statistically significant bacterial reduction, but we could notice a higher frequency of the bacterial reduction with the use of a 21G needle and 20ml syringe.