title: Combination of low-dose bupivacaine and opioids provides satisfactory analgesia with less intraoperative hypotension for spinal anesthesia in cesarean section.
abstract: OBJECTIVE
  This meta-analysis was undertaken to compare the three most common drug regimens of bupivacaine in spinal anesthesia for cesarean section: high-dose bupivacaine (≥10 mg, HB), low-dose bupivacaine (<10 mg, LB) and combination of low-dose bupivacaine and opioids (LBO).
  
  
  METHODS
  Databases of MEDLINE, EMBASE, and Cochrane Library were searched (updated on October 30, 2011). Primary endpoints were the incidence of intraoperative hypotension and analgesia efficacy. Pooled risk ratio (RR) or standard mean difference and their 95% confidence intervals (95% CI) were calculated. A RR <1 indicates that LB or LBO regimen is associated with less intraoperative complications and better anesthesia or analgesia efficacy.
  
  
  RESULTS
  A total of 11 randomized controlled trials including 605 parturients were analyzed. Results of this meta-analysis showed that compared with HB regimen, LB regimen decreased the incidence of intraoperative hypotension (RR = 0.64, 95% CI: 0.42-0.96) with less satisfactory analgesia (fixed model, RR = 1.50, 95% CI: 1.14-1.98). LBO regimen significantly reduced the incidence of intraoperative hypotension (RR = 0.52, 95% CI: 0.33-0.82) with reliable analgesia efficacy (RR = 2.56, 95% CI: 0.77-8.48).
  
  
  CONCLUSIONS
  Compared with conventional HB regimen and LB regimen, LBO regimen not only reduced intraoperative hypotension but also provided reliable analgesia. Therefore, LBO regimen should be considered as the preferred drug combination for spinal anesthesia in cesarean section.
authors.affiliation: Department of Anaesthesiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, China.
authors.forename: Man-Tang
authors.initials: MT
authors.lastname: Qiu
authors.forename: Fu-Qing
authors.initials: FQ
authors.lastname: Lin
authors.forename: Shu-Kun
authors.initials: SK
authors.lastname: Fu
authors.forename: Heng-Bin
authors.initials: HB
authors.lastname: Zhang
authors.forename: Hui-Hua
authors.initials: HH
authors.lastname: Li
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Zhang
authors.forename: Quan
authors.initials: Q
authors.lastname: Li
mesh_terms: D016362:Analgesia, Obstetrical / Q000379:methods*; D000701:Analgesics, Opioid / Q000627:therapeutic use*; D000775:Anesthesia, Spinal; D002045:Bupivacaine / Q000627:therapeutic use*; D016206:Databases, Bibliographic / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D006973:Hypertension / Q000209:etiology / Q000517:prevention & control*; D011183:Postoperative Complications / Q000517:prevention & control
chemical_list: D000701:Analgesics, Opioid; D002045:Bupivacaine