Abstract

Epidural spread of analgesia following the midthoracic injection of 1% etidocaine was examined in a group of 104 patients (44 men and 60 women). The technique was standardized with a paramedian approach in the sitting position at the 6th or 7th thoracic interspace. The volume given varied between 7 and 10 ml according to age and height. Twenty minutes after injection the number of blocked dermatomes was determined by assessing the upper and lower border of analgesia to pinprick. The dose requirements were expressed as dose of 1% etidocaine (ml) injected, divided by the number of analgesic dermatomes. The dose per segment was statistically analyzed with correlation and regression techniques for their relationship with age, height, weight, and sex. Correlations were quite low in general. Only borderline significance at the 5% level was reached for height. For practical purposes there is no way of predicting the spread of analgesia from a dose of 1% etidocaine following thoracic epidural injection.