title: Reducing the concentration to 0.4% enantiomeric excess hyperbaric levobupivacaine (s75: r25) provides unilateral spinal anesthesia. Study with different volumes.
abstract: OBJECTIVE
  Unilateral spinal anesthesia may be obtained with hypobaric or hyperbaric solution. The objective of this study was to compare different doses of enantiomeric excess hyperbaric levobupivacaine to achieve unilateral spinal anesthesia.
  
  
  METHODS
  One hundred and twenty patients were randomized to receive 4 mg, 6 mg or 8 mg of 0.4% enantiomeric excess levobupivacaine. The solutions were administered at the L3-L4, with the patient in a lateral position and kept at this position according to dose administration for 5, 10 or 15 minutes. Sensory block (pinprick) and motor block (scale 0-3) were compared between the operated and contralateral sides.
  
  
  RESULTS
  The onset of analgesia was rapid and comparable between groups. Sensory block was significantly higher in the operated than in nonoperated limb at all times of evaluation. Increasing the dose by 1 mL (2mg) corresponded to an increase of two segments in the mode for the operated side. In the operated side, motor block (MB = 3) of patients occurred in 31 (77.5%) with 4 mg, 38 (95%) with 6 mg, and 40 (100%) with 8 mg. There was a positive correlation between increased dose, blockade duration, and hypotension. All patients were satisfied with the technique used.
  
  
  CONCLUSIONS
  Spinal anesthesia with different volumes of enantiomeric excess hyperbaric bupivacaine (S75: R25) provided a 78% incidence of unilateral spinal block, with the smallest dose used (4 mg) the most efficient.
authors.affiliation: Faculdade de Medicina Nova Esperança, João Pessoa PB, Brazil. dr.imbelloni@terra.com.br
authors.forename: Luiz Eduardo
authors.initials: LE
authors.lastname: Imbelloni
authors.forename: Marildo A
authors.initials: MA
authors.lastname: Gouveia
authors.forename: Antonio Fernando
authors.initials: AF
authors.lastname: Carneiro
authors.forename: Renata
authors.initials: R
authors.lastname: Grigorio
mesh_terms: D000328:Adult; D000775:Anesthesia, Spinal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000737:chemistry; D002045:Bupivacaine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry; D005260:Female; D006801:Humans; D000077554:Levobupivacaine; D008297:Male; D011446:Prospective Studies; D016037:Single-Blind Method
chemical_list: D000779:Anesthetics, Local; D000077554:Levobupivacaine; D002045:Bupivacaine