A prospective study was carried out on 629 surgical wounds to compare the effectiveness of povidone-iodine solution and normal saline in preoperative preparation of the skin for 20 months from Jan. 1982 through Aug. 1983 at Yonsei medical center.
Statistical randomization provided that approximately one half of the patient (303/629) was operated upon in the saline preparation group and the remainder (326/629) in the povidoneiodine preparation group.
The clean wound infection rate was 0.7%(1/140), the clean contaminated wounds. 0.9% (1/112), contaminated wounds, 5.6%(2/36) and dirty wounds, 40%(6/15) in the saline preparation group.
And in the povidone-iodine preparation group, the clean wound infection rate was 0.7%(1/134), the clean-contaminated wounds, 0.9%(1/114), contaminated wounds, 2.1%(1/48) and dirty wounds, 43.3%(13/30).
There was. no significant difference in the standard wound infection rate between 2 groups.
The second study was carried out by surface sampling to give a factual evaluation of surface cleaning efficiency of the two above solutions. ;Direct contact cultures with Rodac plate method were obtained from randomly sampled 20 operative wounds before and after the surfaces are prepared. After control cultures before preparation, each wound was divided into 2 areas and one area was cleaned with gauzes dipped in sterile normal saline and other side was cleaned with povidone-iodine gauzes. Rodac plate was taken from each side after 3 minutes and 5 minutes cleaning.
Colony was counted per plate after 24 hours incubation. The colony counts in the untreated control series ranged from 3 to 300(mean 52) per plate. Following saline preparation for 3 minutes, the range was from 0 to 20 (mean 6), the colony count was reduced about 86.2% in mean and sterility was 20%. Following saline preparation for 5 minutes, the range, 0~2 per plate, reduction rate, 99.8%, and sterility 80% were noted.
Following povidone-iodine preparation for 3 minutes, the range 0~4 per plate, reduction rate, 97.1%, and sterility 65% were noted. Following povidoneiodine preparation for 5 minutes, the range, 01 per plate, reduction rate, 99.8% and sterility 85% were noted.
There was no significant difference in surface cleaning efficiency between povidone-iodine solution and normal saline when the cleaning was carried out about 5 minutes.
The above data suggested the followings;
1.) Mechanical removal of viable bacteria, spores, dust and grease from exposed skin was the essential elements of a skin preparation or surgical scrub.
2.) Wound infections are mostly from the endogenous contamination, especially with intervention in bacterial containing viscera.
3.) Whatever solution or the detergent used on the skin preparation probably has little to do with whether a wound infection will occur.
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