Luz G, Wieser C, Innerhofer P, Frischhut B, Ulmer H, Benzer A
Department of Anaesthesia, University Hospital, Innsbruck, Austria.
Paediatr Anaesth. 1998;8(6):473-8. doi: 10.1046/j.1460-9592.1998.00285.x.
We measured free and total venous bupivacaine plasma concentrations in fourteen infants and children aged 6 days (2800 g) to 9 years (27 kg) undergoing epidural anaesthesia. An initial bolus of 0.5 ml.kg-1 bupivacaine 0.25% was followed by a continuous infusion administered one h after bolus over a period of seven h (first hour 0.25 ml.kg-1.h-1 0.25%; then reduced to 0.125%). Although total bupivacaine plasma concentrations were within acceptable limits (< 1.5 micrograms.ml-1), four of the seven infants showed adverse reactions. Maximum plasma concentrations of free bupivacaine were significantly higher in infants (P < 0.05) than in older children. We conclude that toxicity may be underestimated when only measuring total bupivacaine concentrations. In young infants the bupivacaine dose administered for continuous epidural anaesthesia should be further lowered below recommended concentrations and the patients closely observed for possible adverse reactions.
我们测定了14例年龄在6天（2800克）至9岁（27千克）接受硬膜外麻醉的婴幼儿和儿童的游离和总静脉布比卡因血浆浓度。初始推注0.5毫升·千克-1的0.25%布比卡因，随后在推注1小时后进行持续输注，持续7小时（第一小时0.25毫升·千克-1·小时-1的0.25%；然后降至0.125%）。尽管总布比卡因血浆浓度在可接受范围内（<1.5微克·毫升-1），但7例婴儿中有4例出现了不良反应。婴儿游离布比卡因的最大血浆浓度显著高于大龄儿童（P<0.05）。我们得出结论，仅测量总布比卡因浓度时，毒性可能被低估。对于小婴儿，持续硬膜外麻醉时布比卡因的给药剂量应进一步降低至推荐浓度以下，并密切观察患者是否可能出现不良反应。
