A randomized controlled trial and prospective cohort investigating antivenom for red-bellied black snake envenomation

Figures & data

Figure 1. Flow diagram of patients recruited to the randomized controlled trial and patients not randomized and included in the second analysis.

Table 1. Demographics for patients recruited to the randomized controlled trial and cohort patients not recruited to the randomized controlled trial comparing those administered antivenom within 6 h and those not administered antivenom within 6 h.

Demographics	Randomized controlled trial		Cohort
	Placebo	Antivenom	Nil	Antivenom
Number	7	8	40	28
Age in years; median (interquartile range)	35 (21-59)	57 (37-63)	45 (31-63)	31 (15-58)
Male	5 (71%)	7 (88%)	28 (70%)	22 (79%)
Clinical syndromes
Non-specific systemic symptoms	6 (86%)	7 (88%)	35 (88%)	26 (93%)
Anticoagulant coagulopathy	0	0	8 (20%)	9 (32%)
White cell count > 11 × 10^9/L	5	6	36 (90%)	24 (86%)
Maximum [venom] µg/L; median (interquartile range)	21 (20-24)	16 (8-26)	23 (7-54)^a	22 (7-57)^b

^a 26 patients had venom measured.

^b 23 patients had venom measured.

Figure 2. Scatter plot of the creatine kinase activity [A] and creatine kinase activity-area under the curve_0-48h [B] comparing patients administered antivenom within 6 h and those not administered antivenom within 6 h, for randomized patients (filled blue circles), non-randomized patients (filled green circles) and patients given late antivenom > 6 h (filled red circles).

Figure 3. Plot of creatine kinase activity-area under the curve _0-48h versus time to antivenom for patients given antivenom (open blue circles), patients given late antivenom after an abnormal creatine kinase activity (filled red circles) and patients not given antivenom (open black circles).

Table 2. Outcome for patients administered antivenom and those not given antivenom (within 6 h) for the randomized controlled trial and the cohort patients not recruited to the randomized controlled trial.

	Randomized controlled trial		Cohort
	Placebo	Antivenom	Nil	Antivenom
Number	7	8	40	28
Outcomes
Myotoxicity (creatine kinase activity > 1,000 U/L) n (%)	2 (29%)	0	15 (38%)	3 (11%)
Peak creatine kinase activity (U/L); median (interquartile range)	259 (104-2347)	182 (95-246)	272 (168-507)	348 (179-2845)
Creatine kinase activity-AUC0-48h (U/L*h; median (interquartile range)	197 (0-66353)	0 (0-1124)	182 (0-6812)	4287 (0-63806)
Peak creatine kinase activity > 10,000 U/L	0	0	3 (7%)	1 (4%)
Detectable venom post-treatment n (%)	3 (43%)	0	0/4^b	1/23 (4%)^c
Antivenom reactions
Immediate n (%)	0	2 (25%)	3 (38%)^a	11 (39%)
Serum sickness n (%)	0	1 (13%)	0	1 (4%)
Length of stay (hours); median (interquartile range)	26 (20-70)	23 (22-25)	25 (18-66)	24 (18-43)

^a 3 of 8 that received antivenom > 6 h post-bite.

^b 4 of the 8 patients given antivenom > 6 h post-bite had venom measured.

^c 23 patients had venom measured.

Data availability statement

Data supporting the findings of this study are available on request from the corresponding author [GI]. The data are not publicly available due to confidentiality and ethical requirements.