An improved cannulation technique for prolonged blood sampling of the American bullfrog

A T-cannula was used to collect serial blood samples from the sciatic artery of the American bullfrog (Rana catesbeiana). The horizontal arm of the cannula was implanted in the artery and the vertical arm employed to collect blood samples. The T-cannula allowed blood flow to continue in the cannulated artery and provided long-term, repetitive blood samples from conscious, caged, but otherwise unrestrained and undisturbed animals. The cannula functioned for at least 14 days, the maximum period investigated. Athough developed for studies on amphibians and reptiles, the technique appeared to be applicable, with appropriate modifications, to a variety of small animals.