Table I.

Patient demographics and duration of surgery (mean ± SD)

Parameters	Group A	Group B	Group C	Group D
Age [year]	26 ±6.06	25.92 ±4.22	25.92 ±4.68	27.92 ±4.58
Weight [kg]	73.76 ±7.16	72.52 ±7.68	72.84 ±8.57	75 ±8.15
Duration of surgery [min]	31.56 ±6.69	29.52 ±6.38	26.96 ±5.41	30 ±6.45
Height [cm]	163.44 ±4.01	162.88 ±5.16	163.12 ±4.12	163.64 ±3.04

p > 0.05, group A (n = 25): intrathecal 0.5% isobaric bupivacaine 9 mg + morphine sulfate 200 µg, group B (n = 25): intrathecal 0.5% isobaric bupivacaine 9 mg + fentanyl 25 µg, group C (n = 25): intrathecal 0.5% heavy bupivacaine 12.5 mg + morphine sulfate 200 µg, group D (n = 25): intrathecal 0.5% heavy bupivacaine 12.5 mg + fentanyl 25 µg