Influence of ASA score and Charlson Comorbidity Index on the surgical site infection rates.

Abstract

To compare the frequencies of surgical site infections (SSI) in ASA class-I (American Society of Anaesthesiologists-I) with ASA class II-III and CCI-0 (Charlson Co-morbidity Index-0) with CCI 1-6 in clean (C) and clean contaminated (CC) surgeries. Analytical study. This study was conducted in a General Surgical Unit of Khyber Teaching Hospital, Peshawar, from December 2008 to April 2009. A total of 310 clean and clean contaminated general surgical interventions with pre-operative ASA score of I-III, were included in the study, excluding anal and cystoscopic procedures. On the basis of past medical record, patients were grouped into ASA-I (patients without any co-morbidity) and ASA II-III (patients with co-morbidities) on the basis of their ASA score pre-operatively. In the same way patients were divided into CCI-0 (patients without co-morbidities) and CC 1-6 (patients with co-morbidities) according to CCI score. All the patients were operated in the same environment by the same set of surgeons. Postoperatively the surgical wounds were observed for SSI by using ASEPSIS daily scoring system for one month prospectively. SSI rates in ASA-I was compared with SSI rates in ASA II-III. Similar comparison of SSI rates was performed in CCI-0 and CCI 1-6. Data was tested by using the Fisher's exact test with confidence interval of 95%. The overall SSI rate was 6.1% (n=19) with 4.23% (n=5) in clean cases (C) and 7.29% (n=14) in clean contaminated cases (CC). There were significantly higher surgical site infection rates among patients in ASA II-III than those with ASA-I in clean contaminated surgeries (p=0.003). There were also significantly higher surgical site infection rates among patients with CCI score 1-6 than those with CCI-0 in clean (p=0.024) and clean contaminated (p=0.002). American Society of Anaesthesiologists (ASA) score and Charlson comorbidity index (CCI) has strong influence on SSI rates in clean and clean contaminated cases. Patients' with co-morbidities undergoing clean and clean contaminated general surgical procedures have greater SSI rates than those without any co-morbidity.