If the diagnostic standard for epidural-venous injection of test dose was an increase in HR by 10 bpm using peak-to-peak criteria or an experience of side effects, the accuracy were 88.5% or 84.25% in the elderly and 94. 2% or 95.7% in the young.

• 单独据症状或HR判断试验剂量是否注入血管；准确性分别为老年组84.；2%25或88