title: Influence of a prolonged lateral position on induction of spinal anesthesia for cesarean delivery: a randomized controlled trial.
abstract: BACKGROUND
  Maternal hypotension occurs commonly during cesarean delivery under spinal anesthesia. We evaluated whether hypotension due to aortocaval compression could be prevented by maintaining a lateral position after an intrathecal injection.
  
  
  METHODS
  Eighty-six women undergoing elective cesarean delivery were enrolled. Spinal anesthesia was conducted in the right lateral position using 8 mg of hyperbaric bupivacaine and 15 µg of fentanyl. Patients were randomly assigned to maintain the right lateral position for 6 min before assuming the wedged supine position (group L), or to assume the wedged supine position immediately after the spinal injection (group S). Hypotension was defined as a decrease in mean arterial pressure to <80% of baseline. Ephedrine was given if blood pressure decreased to <70% of baseline. The incidence of hypotension and nausea, ephedrine requirement, maximal block height, and neonatal outcomes were evaluated.
  
  
  RESULTS
  No significant between-group differences were observed in the lowest blood pressure, total ephedrine dose, or incidence of hypotension or nausea. Onset of hypotension was delayed (6 ± 2 vs. 10 ± 3 min, P<0.001), and the sensory block level was more cephalad in group L than in group S (T2 [C8-T5] vs. T4 [T1-T6], P=0.001). Apgar scores did not differ between the groups.
  
  
  CONCLUSIONS
  During spinal anesthesia for elective cesarean delivery, maintaining the lateral position for 6 min after an intrathecal injection of hyperbaric bupivacaine resulted in a more gradual and higher cephalad sensory block, without an increase in the incidence of maternal hypotension.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea.
authors.forename: J W
authors.initials: JW
authors.lastname: Hwang
authors.forename: A Y
authors.initials: AY
authors.lastname: Oh
authors.forename: I A
authors.initials: IA
authors.lastname: Song
authors.forename: H S
authors.initials: HS
authors.lastname: Na
authors.forename: J H
authors.initials: JH
authors.lastname: Ryu
authors.forename: H P
authors.initials: HP
authors.lastname: Park
authors.forename: Y T
authors.initials: YT
authors.lastname: Jeon
authors.forename: S H
authors.initials: SH
authors.lastname: Do
mesh_terms: D000328:Adult; D000775:Anesthesia, Spinal / Q000379:methods*; D002585:Cesarean Section; D005260:Female; D006801:Humans; D007022:Hypotension / Q000517:prevention & control*; D007431:Intraoperative Complications / Q000517:prevention & control*; D056888:Patient Positioning; D011247:Pregnancy; D011446:Prospective Studies; D016037:Single-Blind Method; D013997:Time Factors