RESUMO
OBJECTIVE: to investigate the use of local anaesthetics, in the presence or absence of vasoconstrictors, for perineal repair during spontaneous delivery. DESIGN: double-blind, randomised-controlled trial. SETTING: a birth centre, in the city of Sao Paulo, Brazil. PARTICIPANTS: from June to December 2004, a total of 96 women were allocated into three groups (first-degree perineal lacerations, second-degree perineal lacerations or episiotomy), and treated with local anaesthesia (1% lidocaine or 1% lidocaine with epinephrine) (n=16 per treatment per group). INTERVENTIONS: an initial local infiltration of the anaesthetic solution was given so that episiotomy could be carried out (5ml) and to suture spontaneous lacerations (1ml), followed by repeated doses (1ml) until pain was completely inhibited. MEASUREMENTS AND FINDINGS: the main outcome measurement was the volume of anaesthetic used during episiotomy and perineal suture. Our data suggest that the concomitant use of the vasoconstrictor resulted in a significantly lower average volume used in the treatment of first-degree (1ml, 95% confidence interval (CI) 0.4-1.6) and second-degree (3.7ml, 95% CI 1.6-5.8) lacerations (p=0.002 and 0.001, respectively). A 0.3ml (95% CI 1.5-2.1) average decrease in anaesthetic volume was observed with episiotomy (p=0.724). The maximum volume of anaesthetic used with and without vasoconstrictor was 1-2ml in 95% and 3-4ml in 50% of first-degree lacerations, respectively, and 1-6ml in 88% and 7-15ml in 81% of second-degree lacerations, respectively. For episiotomy, the maximum dose was 15ml, regardless of anaesthetic solution used. KEY CONCLUSIONS: our data confirm the hypothesis that the use of anaesthetics in conjunction with vasoconstrictors is more effective than anaesthetics alone in the repair of perineal lacerations, but not for episiotomy.