[Spinal anaesthesia for Caesarean section: dose injection speed have an effect on the incidence of hypotension?]

To study effect of injection rate on spinal blockade and haemodynamic of spinal bupivacaine for Caesarean section.

Prospective and randomized.

Sixty ASA I-II patients scheduled for elective Caesarean section were randomized to receive either fast (20 seconds, group R, n=30) or slow (60 seconds, group L, n=30) spinal injection of 10 mg of hyperbaric bupivacaine 0.5% associated with 25 microg of fentanyl and 100 microg of morphine. Sensory and motor blockade and haemodynamic parameters were recorded.

Profiles of sensory and motor block were similar in both groups. Variations of arterial blood pressure and total dose of ephedrine were not different between R and L groups. However, the number of patient with systolic blood pressure lower than 100 mmHg were significantly lower in L group than in R group (p=0.04). Incidences of adverse effects were similar in both groups.

Result of the present study suggests that a slow rate of injection would induce lower incidence of hypotension induced by spinal bupivacaine for Caesarean section.