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Coagulation parameters in copperhead compared to other Crotalinae envenomation: secondary analysis of the F(ab')2 versus Fab antivenom trial.
Clin Toxicol (Phila). 2017 Feb; 55(2):109-114.CT

Abstract

CONTEXT

Coagulation derangements in copperhead envenomation are considered less severe than other crotaline envenomations, resulting in recommendations to limit both coagulation testing and antivenom treatment. A prospective, blinded, multicenter, randomized clinical trial comparing the effectiveness of F(ab')2 versus Fab antivenom in crotaline envenomation patients was completed in 2011. We determined the difference between coagulation parameters in copperhead compared to other crotaline envenomations.

METHODS

We performed a post hoc analysis comparing the coagulation parameters (platelets and fibrinogen) prospectively obtained in the aforementioned trial. All the patients received antivenom in one of three treatment arms [F(ab')2 with maintenance, F(ab')2 with placebo maintenance, or Fab with maintenance]. Coagulation parameters were measured at pretreatment baseline, during acute hospitalization, day 5, day 8, and day 15 post-envenomation. Mean platelet count and fibrinogen levels for the copperhead and other crotaline groups were compared. The platelet and fibrinogen point estimates with distribution are presented graphically over time.

RESULTS

122 patients were enrolled in the study. There were 22 patients with copperhead envenomation, 93 with other crotaline envenomations, and 7 that could not be definitively determined. The mean age was 42 (SD 20) years. There was a minor pretreatment difference in mean baseline platelet count between the copperhead group (246 × 109/L 95% CI 215, 277) compared to other crotaline envenomation patients (184 × 109/L 95% CI 167, 202). There was a modest pretreatment difference in mean fibrinogen level between copperhead patients (345 mg/dL 95% CI 277, 415) and other crotaline patients (261mg/dL 95% CI 241, 281). Pretreatment coagulation parameter means were normal and converged post treatment.

CONCLUSION

On average, copperhead envenomations have less severe initial coagulation derangements. However, in mild envenomations, differences in laboratory values are minimal and there is substantial variation in individual patients regardless of species. Species alone should not be used to determine the need for laboratory testing or treatment in crotaline snakebite.

Authors+Show Affiliations

a Division of Emergency Medicine , Duke University , Durham , NC , USA.a Division of Emergency Medicine , Duke University , Durham , NC , USA. b Duke Global Health Institute, Duke University , Durham , NC , USA.c Department of Emergency Medicine , Brody School of Medicine, East Carolina University , Greenville , NC , USA.c Department of Emergency Medicine , Brody School of Medicine, East Carolina University , Greenville , NC , USA.

Pub Type(s)

Comparative Study
Journal Article
Multicenter Study
Randomized Controlled Trial

Language

eng

PubMed ID

27806644

Citation

Gerardo, Charles J., et al. "Coagulation Parameters in Copperhead Compared to Other Crotalinae Envenomation: Secondary Analysis of the F(ab')2 Versus Fab Antivenom Trial." Clinical Toxicology (Philadelphia, Pa.), vol. 55, no. 2, 2017, pp. 109-114.
Gerardo CJ, Vissoci JR, Brown MW, et al. Coagulation parameters in copperhead compared to other Crotalinae envenomation: secondary analysis of the F(ab')2 versus Fab antivenom trial. Clin Toxicol (Phila). 2017;55(2):109-114.
Gerardo, C. J., Vissoci, J. R., Brown, M. W., & Bush, S. P. (2017). Coagulation parameters in copperhead compared to other Crotalinae envenomation: secondary analysis of the F(ab')2 versus Fab antivenom trial. Clinical Toxicology (Philadelphia, Pa.), 55(2), 109-114. https://doi.org/10.1080/15563650.2016.1250275
Gerardo CJ, et al. Coagulation Parameters in Copperhead Compared to Other Crotalinae Envenomation: Secondary Analysis of the F(ab')2 Versus Fab Antivenom Trial. Clin Toxicol (Phila). 2017;55(2):109-114. PubMed PMID: 27806644.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Coagulation parameters in copperhead compared to other Crotalinae envenomation: secondary analysis of the F(ab')2 versus Fab antivenom trial. AU - Gerardo,Charles J, AU - Vissoci,Joao R Nickenig, AU - Brown,Michael W J, AU - Bush,Sean P, Y1 - 2016/11/03/ PY - 2016/11/4/pubmed PY - 2017/2/28/medline PY - 2016/11/4/entrez KW - Agkistrodon contortrix KW - Snakebite KW - fibrinogen KW - platelet SP - 109 EP - 114 JF - Clinical toxicology (Philadelphia, Pa.) JO - Clin Toxicol (Phila) VL - 55 IS - 2 N2 - CONTEXT: Coagulation derangements in copperhead envenomation are considered less severe than other crotaline envenomations, resulting in recommendations to limit both coagulation testing and antivenom treatment. A prospective, blinded, multicenter, randomized clinical trial comparing the effectiveness of F(ab')2 versus Fab antivenom in crotaline envenomation patients was completed in 2011. We determined the difference between coagulation parameters in copperhead compared to other crotaline envenomations. METHODS: We performed a post hoc analysis comparing the coagulation parameters (platelets and fibrinogen) prospectively obtained in the aforementioned trial. All the patients received antivenom in one of three treatment arms [F(ab')2 with maintenance, F(ab')2 with placebo maintenance, or Fab with maintenance]. Coagulation parameters were measured at pretreatment baseline, during acute hospitalization, day 5, day 8, and day 15 post-envenomation. Mean platelet count and fibrinogen levels for the copperhead and other crotaline groups were compared. The platelet and fibrinogen point estimates with distribution are presented graphically over time. RESULTS: 122 patients were enrolled in the study. There were 22 patients with copperhead envenomation, 93 with other crotaline envenomations, and 7 that could not be definitively determined. The mean age was 42 (SD 20) years. There was a minor pretreatment difference in mean baseline platelet count between the copperhead group (246 × 109/L 95% CI 215, 277) compared to other crotaline envenomation patients (184 × 109/L 95% CI 167, 202). There was a modest pretreatment difference in mean fibrinogen level between copperhead patients (345 mg/dL 95% CI 277, 415) and other crotaline patients (261mg/dL 95% CI 241, 281). Pretreatment coagulation parameter means were normal and converged post treatment. CONCLUSION: On average, copperhead envenomations have less severe initial coagulation derangements. However, in mild envenomations, differences in laboratory values are minimal and there is substantial variation in individual patients regardless of species. Species alone should not be used to determine the need for laboratory testing or treatment in crotaline snakebite. SN - 1556-9519 UR - https://www.unboundmedicine.com/medline/citation/27806644/Coagulation_parameters_in_copperhead_compared_to_other_Crotalinae_envenomation:_secondary_analysis_of_the_F_ab'_2_versus_Fab_antivenom_trial_ L2 - http://www.tandfonline.com/doi/full/10.1080/15563650.2016.1250275 DB - PRIME DP - Unbound Medicine ER -