Patients in group S (spinal anesthesia for Caesarean section) received 750-1000 mL of 0,9% NaCI solution (10-15 mL/kg) as infusion in 20-30 minutes. Under strict aseptic precautions a 25G Quincke spinal needle was introduced into L3-L4 or L4-L5 intervertebral space in midline approach in sitting posture, and, after confirming free flow of CSF, predetermined 10-11 mg of drug solution (hypertonic bupivacaine 0,5%) was injected. We let the operation begin when sensory and motor blockade were verified. Oxygen of 100% (3 L. min) was administered throughout the operation via nasal cannula.