The use of phentolamine in the prevention of dopamine-induced tissue extravasation.

PURPOSE: The purpose of this study was to determine whether dopamine-induced tissue extravasation injury could be prevented with phentolamine.

MATERIALS AND

METHODS

This was a prospective, randomized, blinded, and controlled animal study. Forty rats were evaluated to document the effects of dopamine compared with normal saline on tissue integrity, whether any tissue damage was concentration or volume dependent, and to determine the minimum concentration of dopamine resulting in tissue injury. Dopamine concentrations of 0.8 mg/mL and 3.2 mg/mL were tested. In a second part of this study, an additional 40 rats were evaluated to assess the efficacy of two different doses of phentolamine (0.5 mg and 1 mg) or normal saline, when injected within 10 minutes of dopamine administration to prevent or reverse tissue extravasation. Extravasation sites were evaluated clinically and histologically at 2, 4, 6, and 8 hours and were compared with a baseline sample. Outcome measures were as follows: (1) prebiopsy was ectodermal erythema, induration, and blanching; (2) postbiopsy was bubbling, darkening, pallor, and hematoma of the muscle fascia. Histology included neutrophil migration, mast cell degranulation, edema, and hemorrhage. Fisher's Exact Test with the Bonferroni method were used for statistical analysis.

RESULTS

Dopamine-induced extravasation resulted in tissue injury characterized by blanching and hematoma. Damage did not appear to be volume dependent, but may be related to the duration of infiltration. Subcutaneous injection with either dose of phentolamine appeared to be clinically effective in preventing tissue injury. However, microscopic evaluation of tissue samples was inconclusive.

CONCLUSION

This study clinically supported the use of phentolamine for the prevention of dopamine-induced extravasation injury.