[Postoperative infection and anesthesia: analysis of various risk factors]

To study the possible relation between anesthetic techniques and other perioperative circumstances and factors and the presentation of infections after surgery.

We studied 22 patients who suffered infections after surgery and 54 who did not, analyzing the anesthetic technique used as well as other data on age, sex, concomitant disease, toxic habits, practice of invasive procedures, duration and nature of the surgical procedure and the use of antibiotic prophylaxis. Multivariate analysis (logistical regression) was performed in order to identify independent risk factors.

None of the anesthetic techniques studied was associated with greater frequency of postoperative infection. Infected patients were significantly older than uninfected patients (75 +/- 9 years versus 61 +/- 18 years). Likewise the number of infections was higher among ASA III and IV (n = 20) patients than among ASA I and II (n = 2). The duration of surgery for infected patients was 4.15 +/- 2.12 hours whereas it was 2.87 +/- 1.86 hours (p < 0.001) for uninfected patients. Placement of a urinary catheter, repeated surgery, diabetes and blood transfusion all signified greater risk of infection, as did prophylaxis with second and third generation cephalosporins (OR = 12.5; 95% CI = 1.8-85.6) or tobramycin (OR = 66.4; 95% CI = 3.5-1,270).

The risk of postoperative infection increases with age and poor physical status of patients (ASA III and IV), with diabetes, repeated surgery, transfusion of blood products and prophylaxis with third generation cephalosporins and tobramycin.