Background: Siriraj hospital is a tertiary-care teaching hospital. Ever since 2015, an acute care surgery division has been founded, overall, resulting in less pre-operative time of patient care. The most common problem is acute appendicitis so that the rate of negative appendectomy and complicated appendicitis have been used to compare with the past. In our country, the diagnosis of appendicitis still based on clinical manifestations and routine laboratory investigation. The correlation between the clinical characteristics and pathological subgroups was also determined in our study.
Objective: This study was designed to compare the rates of negative appendectomy and complicated appendicitis of patients
who underwent urgency appendectomy between one-year before and after the establishment of acute care surgery division. Another purpose is to find the risk factors of negative appendectomy and complicated appendicitis.
Results: All 691 (344 in 2014 and 347 in 2015) patients’ data were retrospectively collected. In 2015, the average age (39 year), pre-hospital time (24 hour), and portion of pre-operative imaging investigation (18.4%) were not significantly different from 2014. The female ratio was 50.9% in 2014 and 60.8% in 2015 (p = 0.009). The in-hospital pre-operative time was reduced for 102 minutes (5 hour 25 minute in 2014 to 3 hour 43 minute in 2015 p<0.001). The rate of negative appendectomy was 13.3%, and the rate of complicated appendicitis was 21.3% which not different between two years (p = 0.207). The length of stay of either period was similar at 2.5 days. The risk factors of negative appendectomy group were as followed: female gender, age <45, no vomiting, no fever, no guarding, and normal white blood cell counts. Whereas, the risk
factors for complicated appendicitis were seen in the elderly from 45 years onwards, prolonged pre-hospital period after
symptom onsets >12 hours, associated symptoms of anorexia and diarrhea, body temperature >38.5, tachycardia, tenderness
beyond RLQ and guarding sign in physical examination, Neutrophil and band forms percentage >75%, and pre-operative imaging studies.
Conclusion: First year of acute care surgery division, we could reduce the burden of pre-operative interval for 1 hour 42 minute compared to 2014. The rate of negative appendectomy (13.3%) and complicated appendicitis (21.3%) were not different from previous year. Many of ordinary clinical findings were reliably implemented to predict the negative appendectomy and complicated appendicitis patient.

Keywords: Negative appendectomy, Perforated appendicitis, Acute care surgery