The medical records of 111 patients who visited Wonju Severance Christian Hospital from January 2008 to December 2012 for the management of venomous snakebite wounds were retrospectively reviewed, and 46 patients who required surgical management were included. To eliminate cases in which the cause of the bite wound was unclear, cases were only included if the wound site showed two fang marks. The following exclusion criteria were also used in the study: refusal to be monitored for 6 hours with a severity of Grade I or lower, refusal to be admitted for a severity of Grade II or higher, previous history of coagulation difficulty, age of 18 years or younger, history of administration of antivenom injection in another hospital, follow-up loss, and refusal to be included in the study.

The guidelines for the management of snakebite were developed based on the author's experiences and on published studies (both domestic and abroad) (Fig. 1). Vital signs of patients were checked upon arrival to the emergency room, and the species of the responsible snake was confirmed during history-taking. The severity of the bite wound was evaluated primarily to determine the administration of antivenom, and laboratory tests including complete blood count, general chemistry, coagulation profile, and creatinine kinase were performed to discover and manage systemic symptoms or treatments.

The classification proposed by Parrish, McCollough, and Gennard (Table 1),5 which was based on clinical findings and blood laboratory testing, was used to evaluate the severity of the bite wound and to determine the use of antivenom. The wound was irrigated with normal saline and then soaked with Betadine solution in cases in which antivenom was not provided. Antivenom was routinely administered to patients with a severity of Grade II or higher regardless of whether the venom source was confirmed or unknown. Antivenom was also provided regardless of patient severity in cases of swelling, erythema, and severe pain involving two or more joint surfaces adjacent to the bite wound. The decision to administer antivenom was also made after clinical reassessments, including checking blood laboratory tests (same as above) every 6 hours, checking vital signs every 30 minutes, and reexamining the wound. A skin reaction test was performed prior to antivenom administration in order to prevent anaphylactic shock or serum sickness. The skin test was performed with a 1-mL mixture of antivenom powder effective against A. brevicaudus (KoVax Dried Antivenom Injection, Korea Vaccine) and sodium chloride solution, which was then mixed with 9 mL normal saline. Then, 0.1 mL of the solution was injected subcutaneously, and the antivenom was discontinued in cases of positive results including erythema or swelling greater than 1 cm and shock. In cases of equivocal results, the remaining 0.9 mL of the solution was administered subcutaneously, and patients were assessed for a positive reaction after 30 minutes. The initial dose of antivenom was 6000 IU in cases of Grade II injury and 12000 IU in cases of more severe injury. A booster dose of 50% of the initial dose was provided if there was no clinical improvement within 12 hours after the initial administration or in the following cases: elevated PT/PTT, INR greater than 2, increased subcutaneous hemorrhage at the bite wound site, decreased blood pressure, or altered mental state. Antihistamine (pheniramine 4 mg) and hydrocortisone (Solu-Cortef 100 mg) were also provided to protect against complications associated with antivenom use (anaphylactic shock, decreased blood pressure, pulmonary edema, decreased cardiac output). All patients were also vaccinated against tetanus and prophylactic antibiotics (Quinolone). In cases in which antivenom was not provided, debridement of the wound followed by saline irrigation and Betadine soaking was immediately performed. If antivenom was provided, delayed debridement was performed 72 hours after the injury, and wound soaking was performed twice daily with acidic water made using a medical ionic-water generator (Dion Magic, Shenpix, Japan). Debridement was performed to remove as much of the necrotized tissue as possible until healthy tissue was revealed.6 Grade 0 and I patients were discharged after confirming the absence of clinical worsening (wound site pain, swelling progressing, etc.) during 6 hours of observation and normal blood laboratory test results. Patients with a severity of Grade II or higher were admitted. In cases in which surgical intervention was provided, follow-up outpatient visits were scheduled for 7 and 28 days after discharge.

Debridement was required in 46 of 111 patients (41.4%) with snakebite. Patients who skipped antivenom and underwent immediate debridement due to positive skin reaction against antivenom or due to injury caused by the Rhabdophisgenus (no antivenom exists for this genus) were classified as group A (10 patients, 21.7%), and patients who underwent delayed debridement after receiving antivenom were classified as group B (36 patients, 78.2%). The disease severity, mean age, past history, wound location, blood laboratory test results, timing of debridement, type of surgical intervention, and complications were compared between groups. Complications resulting from antivenom administration, including anaphylactic shock and decreased blood pressure, were also studied.

Statistical analysis was performed with SPSS version 13.0 (IBM Corp., Chicago, IL, USA), and the statistical difference between the two groups was determined with the Mann-Whitney U test or chi-square test. Statistical analysis involving stratification of severity was performed using the Kruskal-Wallis test, and Fisher's exact test was used for frequencies of less than 5. p<0.05 was set as statistically significant.

A total of 46 patients with snakebite who required surgical management were included. The mean age was 52.3±14.8 years, and there were 32 males and 14 females. The male-to-female ratio was approximately 2.3:1. The mean time to the emergency room was 122±184 minutes, and the mean duration of hospital stay was 8.4±2.3 days. There was no significant difference in injury grade. The most frequent site of injury included the fingers and hand (30 patients, 65.2%) (Table 2).

In group A, Grade I comprised the largest portion of patients (6, 60%). Group B included 20 patients (55.5%) with Grade II disease, suggesting relatively higher severity; however, the difference was not statistically significant. Age, sex, and past history were also similar between the two groups. The hand was the most frequent injury site for both groups, and no significant difference in injury site distribution was noted (Table 3).

In group A, two of three Grade II patients developed cellulitis, and a skin graft under general anesthesia was performed for a single case due to skin necrosis. In group B, cellulitis developed in nine patients, and two of them underwent a skin graft due to skin necrosis. Also, one Grade III patient in group B developed compartment syndrome, and fasciotomy under general anesthesia was performed. The wound was sutured 2 weeks later; however, partial skin necrosis developed, for which a skin graft was performed.

There were no surgical complications in either group that resulted in permanent functional disability, such as amputation, permanent joint contraction, neurologic damage, or osteomyelitis. A skin rash was found on one patient in group B and was treated with antihistamine.

There were one and four incidences of rhabdomyolysis in group A (10.0%) and group B (11.1%), respectively. Disseminated intravascular coagulation occurred in two patients in group A (20.0%) and seven patients in group B (19.4%). Progression to acute renal failure occurred in one case in group A (10.0%) and three cases in group B (8.3%). All complications were treated at the early phase, and there were no incidences of severe complication or mortality (Table 4).