Real world delays in antivenom administration: patient, snake or hospital factors (ASP-33)

Objective: Early antivenom administration is essential for effective treatment. We investigated the delays in antivenom administration.

Methods: We reviewed snakebites from the Australian Snakebite Project (2006-2021) given antivenom, presenting to hospital within 12 h. We extracted demographics, snake type, time of bite, hospital arrival, blood collection, antivenom treatment and hospital transfer.

Results: There were 2,169 patients recruited to Australian Snakebite Project 1,132 patients received antivenom within 12 h of the bite, and 1,019 of these were envenomated: median age 41 years (IQR: 24-57 years); 738 (72%) males. A pressure bandage was applied in 950 (93%), a median of 15 min (IQR: 5-30 min) post-bite. Specific snakes were identified by venom assays in 855 patients (80%), including 328 brown snakes (32%), 173 tiger snakes (17%), 74 rough-scaled snakes (7%), 85 red-bellied black snakes (8%), 49 taipans (5%) and 26 death adders (3%). Seventy-seven patients (7%) received antivenom without envenomation. The median length of hospital stay was 41 h (IQR: 24-67 h). The median time to hospital was 60 min (IQR: 30-105 min), to first blood tests was 90 min (IQR: 59-154 min) and to antivenom was 235 min (IQR: 155-345 min). There was a median delay in blood tests of 20 min (IQR: 10-37 min) and a median delay to antivenom of 147 min (IQR: 84-249 min). Non-specific systemic symptoms occurred in 641 (63%) patients, which occurred a median of 24 min (IQR: 10-60 min) post-bite, which was at a median of 180 min (IQR: 106 to 275 min) prior to antivenom administration. Time to antivenom in the 314 transferred patients was similar to those not transferred. Time to antivenom was significantly shorter for 189 patients given antivenom prior to transfer, median 183 min (IQR: 110-270 min), compared to 130 patients given antivenom after transfer, median 363 min (IQR: 289-513 min; P <0.001).

Discussion: Antivenom administration was delayed on average by 2.5 h after hospital presentation, despite three-quarters arriving in hospital within 3 h, the optimal time for antivenom administration. Patients requiring transfer received antivenom in a similar time, but earlier if administered prior to transfer, highlighting the possible benefits of pragmatic clinical decision-making prior to blood tests.

Conclusion: We found the leading cause of delays to antivenom administration after patients arrive in hospital was waiting for blood results. Systemic symptoms occurred early in most cases and could be given greater weight in decisions about early antivenom.