[Effects of drug dose on spinal anesthesia with isobaric tetracaine]

A protocol similar to that established in our previous reports was used in the current study. A total of 128 demographically compatible patients were studied using various tetracaine dosages in 2 ml isobaric solution; fifty patients (group I) received 10 mg, 46 patients (group II) received 15 mg, and 32 patients (group III) received 20 mg. Except for the drug dosage, an identical technique was employed for every patient in the study. The highest sensory levels were T7 (median, range T5-12) for group I, T5 (median, range T3-8) for group II, and T4 (median, range C8-T5) for group III, with an onset time of 7.08 +/- 1.16, 10.37 +/- 1.69 and 11.14 +/- 1.85 min respectively. The above differences are statistically significant (p less than 0.05). However the differences between their onset times to the T10 level were not statistically significant (p greater than 0.05). The 2-segment regression times were 180.5 +/- 53.44 min for group I, 216.4 +/- 37.3 min for group II and 248.7 +/- 38.6 min for group III. The difference between group I and group II as well as group I and group III were statistically significant (p less than 0.01) but not significant between group II and group III (p greater than 0.05). The onset times of maximum motor blockade assessed by modified Bromage scale were 5.42 +/- 1.59, 5.28 +/- 1.36 and 5.37 +/- 1.42 min.(ABSTRACT TRUNCATED AT 250 WORDS)