Microbial colonization of open abdomen in critically ill surgical patients

This study was designed to describe the time-course and microbiology of colonization of open abdomen in critically ill surgical patients and to study its association with morbidity, mortality and specific complications of open abdomen. A retrospective cohort analysis was done.

One hundred eleven consecutive patients undergoing vacuum-assisted closure with mesh as temporary abdominal closure method for open abdomen were analyzed. Microbiological samples from the open abdomen were collected. Statistical analyses were performed using Fisher's exact test for categorical variables. Mann-Whitney U test was used when comparing number of temporary abdominal closure changes between colonized and sterile patients. Kaplan-Meier analysis was done to calculate cumulative estimates for colonization. Cox regression analyses were performed to analyze risk factors for colonization.

Microbiological samples were obtained from 97 patients. Of these 76 (78 %) were positive. Sixty-one (80 %) patients were colonized with multiple micro-organisms and 27 (36 %) were cultured positive for candida species. The duration of open abdomen treatment adversely affected the colonization rate. Thirty-three (34 %) patients were colonized at the time of laparostomy. After one week of open abdomen treatment 69, and after two weeks 76 patients were colonized with cumulative colonization estimates of 74 % and 89 %, respectively. Primary fascial closure rate was 80 % (61/76) and 86 % (18/21) for the colonized and sterile patients, respectively. The rate of wound complications did not significantly differ between these groups.

Microbial colonization of open abdomen is associated with the duration of open abdomen treatment. Wound complications are common after open abdomen, but colonization does not seem to have significant effect on these. The high colonization rate described herein should be taken into account when primarily sterile conditions like acute pancreatitis and aortic aneurysmal rupture are treated with open abdomen.