Deleterious effect of urokinase used to treat experimental intra-arterial thiopental injection injuries.
Inadvertent arterial drug injections continue to be an important source of morbidity. Although the clinical picture of thiopental injection has been well defined over the past 50 years, there is still much controversy concerning pathophysiology and treatment regimen. Recently, a case report showed the efficacy of urokinase in treating this problem. The current study used the reliable ear model to study more closely this phenomenon. Rabbits were divided into four groups. Ears in Group 1 rabbits (n = 10) received an intra-arterial thiopental (15 mg/kg) injection. Group 2 rabbits (n = 10) received thiopental followed by a 1-ml saline injection 15 minutes later. Group 3 rabbits (n = 10) received thiopental followed by 50,000 U of urokinase. Finally, Group 4 rabbits (n = 4) received an intra-arterial injection of saline alone. Necrosis was evaluated 2 weeks later and expressed as a percentage. Student's t tests were used to evaluate data significance.


RESULTS
Group 1 (thiopental alone) and Group 2 (thiopental and saline) rabbits had significantly more necrosis than Group 4 (saline alone) rabbits, 21.2% and 17.5% versus 0% (p less than 0.001 for both). Group 3 (thiopental and urokinase) rabbits had significantly more necrosis (46.5%) than Groups 1 and 2 rabbits (p less than 0.001 for both).


CONCLUSIONS
From this study, we found that treatment of intra-arterial thiopental injection injuries with urokinase was of no benefit, but more importantly, it increased tissue necrosis by approximately 100%. Clinical use of this treatment is to be discouraged until underlying mechanisms are better defined.
Angel
M F
MF
Department of Plastic Surgery, University of Virginia, Charlottesville.
Amiss
E C
EC
Amiss
L R
LR
Morgan
R F
RF
D000818:Animals; D007269:Injections, Intra-Arterial; D007511:Ischemia / Q000139:chemically induced*; D009336:Necrosis; D011817:Rabbits; D012867:Skin / Q000098:blood supply*; D013874:Thiopental / Q000008:administration & dosage / Q000633:toxicity*; D014568:Urokinase-Type Plasminogen Activator / Q000008:administration & dosage / Q000633:toxicity*
D014568:Urokinase-Type Plasminogen Activator; D013874:Thiopental