Emmett R S, Cyna A M, Andrew M, Simmons S W
Department of Obstetrics and Gynaecology Anaesthesia, Women's and Children's Hospital, 72 King William Road, Adelaide, South Australia, Australia.
Cochrane Database Syst Rev. 2002(3):CD002251. doi: 10.1002/14651858.CD002251.
Maternal hypotension is the most frequent complication of spinal anaesthesia for caesarean section. Most workers define hypotension as a maternal systolic blood pressure below 70-80% of baseline recordings and/or an absolute value of < 90 - 100mmHg. Hypotension is often associated with nausea and vomiting and, if severe, poses serious risks to mother (unconsciousness, pulmonary aspiration) and baby (hypoxia, acidosis and neurological injury). Several strategies are currently used to prevent or minimise hypotension but there is no established ideal technique.
To assess the relative efficacy and side effects of prophylactic interventions for hypotension following spinal anaesthesia for caesarean section.
The Cochrane Pregnancy and Childbirth Group Trials Register (January 2002) and the Cochrane Controlled Trials Register (Cochrane Library, Issue 4, 2001).
All published or unpublished randomised controlled trials comparing interventions to prevent hypotension with placebo or alternative treatment in women having spinal anaesthesia for caesarean section.
Trials identified from searching are assessed for inclusion by the same two reviewers independently. Studies are excluded from review where: hypotension is not an outcome measure or clearly defined prior to administering a rescue treatment; randomisation is unsatisfactory; the spinal anaesthetic technique or dose of local anaesthetic is not controlled-for; and the intervention is implemented in response to a fall in blood pressure rather than for prevention. Review Manager software is used for calculation of the treatment effect, represented by relative risks and proportional and absolute risk reductions.
Twenty-five trials (1477 women) meet our inclusion criteria. Four of fifteen interventions reviewed reduce the incidence of hypotension under spinal anaesthesia for caesarean section: (1) crystalloid versus control, relative risk (RR) 0.78 (95% confidence interval (CI) 0.63, 0.98); (2) pre-emptive colloid administration versus crystalloid, RR 0.54 (95% CI 0.37, 0.78); (3) ephedrine versus control, RR 0.69 (95% CI 0.57, 0.84); and (4) lower limb compression versus control, RR 0.70 (95% CI 0.59, 0.83). Ephedrine is associated with dose-related maternal hypertension and tachycardia, and fetal acidosis of uncertain clinical significance.
REVIEWER'S CONCLUSIONS: No intervention reliably prevents hypotension during spinal anaesthesia for caesarean section. No conclusions are drawn regarding rare adverse effects of interventions due to their probable low incidence and the small numbers of women studied. Further trials are recommended, in particular assessing a combination of the beneficial interventions, ie colloid or crystalloid preloading, ephedrine administration and leg compression with bandages, stockings or inflatable boots.
产妇低血压是剖宫产脊髓麻醉最常见的并发症。大多数研究人员将低血压定义为产妇收缩压低于基线记录的70 - 80%和/或绝对值<90 - 100mmHg。低血压常伴有恶心和呕吐，严重时会给母亲（意识丧失、肺误吸）和婴儿（缺氧、酸中毒和神经损伤）带来严重风险。目前有几种策略用于预防或尽量减少低血压，但尚未确立理想的技术。
评估剖宫产脊髓麻醉后预防低血压的预防性干预措施的相对疗效和副作用。
Cochrane妊娠与分娩组试验注册库（2002年1月）和Cochrane对照试验注册库（Cochrane图书馆，2001年第4期）。
所有已发表或未发表的随机对照试验，比较剖宫产脊髓麻醉女性中预防低血压的干预措施与安慰剂或替代治疗。
由两名相同的审阅者独立评估检索到的试验是否符合纳入标准。在以下情况下，研究被排除在综述之外：低血压不是结局指标或在给予抢救治疗之前未明确界定；随机化不充分；脊髓麻醉技术或局部麻醉剂剂量未得到控制；干预措施是在血压下降后实施而非预防。使用Review Manager软件计算治疗效果，以相对风险、比例和绝对风险降低表示。
25项试验（1477名女性）符合我们的纳入标准。在审查的15项干预措施中，有4项可降低剖宫产脊髓麻醉下低血压的发生率：（1）晶体液与对照，相对风险（RR）0.78（95%置信区间（CI）0.63，0.98）；（2）预防性胶体给药与晶体液，RR 0.54（95%CI 0.37，0.78）；（3）麻黄碱与对照，RR 0.69（95%CI 0.57，0.84）；（4）下肢加压与对照，RR 0.70（95%CI 0.59，0.83）。麻黄碱与剂量相关的产妇高血压和心动过速以及临床意义不确定的胎儿酸中毒有关。
没有干预措施能可靠地预防剖宫产脊髓麻醉期间的低血压。由于干预措施的罕见不良反应可能发生率低且研究的女性数量少，因此未得出相关结论。建议进行进一步试验，特别是评估有益干预措施的组合，即胶体或晶体液预负荷、麻黄碱给药以及用绷带、长袜或充气靴进行腿部加压。
