Can surgical need in patients with Naja atra (Taiwan or Chinese cobra) envenomation be predicted in the emergency department?

Abstract

Objectives: To investigate the clinical predictors and the aetiologies for surgery in patients with Naja atra (Taiwan or Chinese cobra) envenomation. Methods: This case series was conducted in the only tertiary care centre in eastern Taiwan. Patients who presented to the emergency department with Naja atra bite between January 2008 and September 2014 were included. Clinical information was collected and compared between surgical and non-surgical patients. Results: A total of 28 patients with Naja atra envenomation presented to the emergency department during the study period. Of these, 60.7% (n=17) required surgery. Necrotising fasciitis (76.5%) was the main finding in surgery. Comparisons between surgical and non-surgical patients showed skin ecchymosis (odds ratio=34.36; 95% confidence interval, 2.20-536.08; P=0.012) and a high total dose of antivenin (≥6 vials; odds ratio=14.59; 95% confidence interval, 1.10-192.72; P=0.042) to be the most significant predictors of surgery. The rate of bacterial isolation from the surgical wound was 88.2%. Morganella morganii (76.5%), Enterococcus faecalis (58.8%), and Bacteroides fragilis (29.4%) were the most common pathogens involved. Bacterial susceptibility testing indicated that combined broadspectrum antibiotics were needed to cover mixed aerobic and anaerobic bacterial infection. Conclusions: Patients with Naja atra envenomation who present with skin ecchymosis or the need for a high dose of antivenin may require early surgical assessment. Combined broad-spectrum antibiotics are mandatory.