Background This study aims to establish compliance levels to prescription guidelines among Australian surgeons in the use of antibiotics in the surgical management of appendicitis. The secondary outcomes are predictors of post‐operative infective complications; surgical site infection (SSI) and intra‐abdominal abscess (IAA) at 30 days. Methods A multi‐centre, prospective, observational study was conducted over a period of 2 months with a 30‐day follow‐up. Patients were eligible for recruitment if they underwent appendicectomy for suspected appendicitis. Antibiotics prescription practices were recorded and compared to national guidelines. Results A total of 1189 patients were recruited across 27 centres; 1081 (92.1%) patients were given prophylactic antibiotics at the time of appendicectomy. Patients with gangrenous appendicitis were more likely to receive prophylactic antibiotics (98.9%); lower rates of use were seen in the non‐appendicitis group (85.7%). A total of 619 (53.3%) patients received antibiotics in the post‐operative period. Despite recommendations, 300 (44.3%) patients with simple appendicitis received post‐operative antibiotics. Only six (2.9%) patients with complicated appendicitis did not receive antibiotics. Overall, SSI and IAA rates were 1.9% and 2.7%, respectively. Aboriginal and Torres Strait Islanders (P = 0.02) and patients with converted operations (P = 0.001) were more likely to have a SSI. Patients with complicated appendicitis and those operated on by a consultant were more likely to increase the odds of IAA (odds ratio 3.8 and 5.1, respectively). Conclusion This broad‐based study shows mixed compliance with antibiotic guidelines in the surgical management of appendicitis in Australia. The use of post‐operative antibiotics in patients with simple appendicitis should be a target for antimicrobial stewardship programmes to prevent antibiotic over‐utilization.

No abstract

Background: Acute appendicitis is a common general surgical condition where diagnosis is predominantly clinical, with the aid of adjunct investigations. This study reviews the relationship between normal and elevated biochemical inflammatory markers, duration of symptoms and proven appendicitis. Methods: A multicentre prospective observational study was performed across 27 centres and included a total of 949 patients with clinical suspicion of appendicitis, who had both white cell count (WCC) and C-reactive protein (CRP) recorded and underwent appendicectomy. Results: A total of 90.4% of patients with raised WCC and CRP had appendicitis with a positive predictive value (PPV) of 0.9 and negative predictive value (NPV) of 0.4. Sensitivity and specificity of elevated WCC (sensitivity 66.5%, specificity 66.0%) and elevated CRP (sensitivity 77.3%, specificity 52.0%) lie within ranges identified by previous studies. A total of 39.8% of patients with normal CRP and WCC had appendicitis. Sensitivity and PPV for patients with elevated inflammatory markers were high until 48 h of symptoms (sensitivity 94%, PPV 0.87). NPV was elevated after 24 h (NPV 0.65 in patients with 24-48 h of symptoms, and 0.61 after 48 h), whilst those with symptoms less than 24 h had a lower NPV of 0.52. Conclusion: Whilst elevated inflammatory markers are a helpful aid in the diagnosis of appendicitis, they should not be relied on by themselves. Nor can normal inflammatory markers be used to exclude appendicitis, even in those with prolonged duration of symptoms. The diagnosis of appendicitis should be guided by a combination of clinical judgement with the assistance of inflammatory markers.

The primary outcome was to investigate the accuracy of intraoperative macroscopic diagnosis by the operating surgeon with the results of the subsequent histopathologic examination. The secondary outcome was to identify the predictors of discrepancies between these 2 groups. Materials and Methods: A multicentre, prospective, observational study was conducted over a period of 2 months with a 30-day follow-up period. Patients who underwent surgery with the intention of appendicectomy were recruited in the study. Results: A total of 1169 patients were recruited. False negatives (FNs) were defined as a normal macroscopic diagnosis but histopathologically appendicitis, whereas false positive otherwise. Overall, FN rates were 22.4%, whereas false positive rates were 8.2%. The seniority of the operating surgeons did not affect the ability to accurately diagnose appendicitis macroscopically (P = 0.069). However, consultant surgeons had the lowest FN rate of 15.6%. Females and preoperative ultrasound scan increased odds of FN, whereas preoperative computed tomography decreased the odds of FN appendicectomy. Conclusion: Macroscopic identification intraoperatively is inaccurate with a FN rate of 22%.