title: Modelling of the optimal bupivacaine dose for spinal anaesthesia in ambulatory surgery based on data from systematic review.
abstract: BACKGROUND
  Spinal bupivacaine is used for day-case surgery but the appropriate dose that guarantees hospital discharge is unknown.
  
  
  OBJECTIVE
  We sought to determine the spinal bupivacaine dose that prevents delayed hospital discharge in ambulatory surgery.
  
  
  METHODS
  Systematic review of clinical trials.
  
  
  METHODS
  Comprehensive search in electronic databases of studies published between 1996 and 2014 reporting the use of spinal bupivacaine in ambulatory patients. Additional articles were retrieved through hyperlinks and by manually searching reference lists in original articles, review articles and correspondence published in English and French.
  
  
  METHODS
  Data were used to calculate, motor block duration and discharge time, an estimated maximal effect (Emax: maximum theoretical time of motor block) and the effective dose to obtain half of Emax (D50) with 95% confidence intervals (CIs). A simulation was performed to determine the dose corresponding to a time to recovery of 300 min for motor function, and 360 min for discharge, in 95% of the patients.
  
  
  RESULTS
  In total, 23 studies (1062 patients) were included for analysis of the time to recovery of motor function, and 12 studies (618 patients) for the time to hospital discharge. The Emax for recovery of motor function was 268 min [95% CI (189 to 433 min)] and the D50 was 3.9 mg [95% CI (2.3 to 6.2 mg)]. A 7.5-mg dose of bupivacaine enables resolution of motor block and ambulation within 300 min in 95% of the patients. A 5-mg dose or less was associated with an unacceptable failure rate.
  
  
  CONCLUSIONS
  Ambulatory surgery is possible under spinal anaesthesia with bupivacaine although the dose range that ensures reliable anaesthesia with duration short enough to guarantee ambulatory management is narrow.
authors.affiliation: From the Service d'Anesthésie Réanimation, Hôpital Tenon, AP-HP, Paris (AL, FB), Service d'Anesthésie Réanimation, Hôpital Bicêtre, AP-HP (JXM), Laboratoire d'Anesthésie UMR788, Université Paris-Sud Faculté de Médecine du Kremlin-Bicêtre, Bicêtre (JXM), and UPMC, Faculté de médecine St Antoine, Paris, France (FB).
authors.forename: Adrien
authors.initials: A
authors.lastname: Lemoine
authors.forename: Jean X
authors.initials: JX
authors.lastname: Mazoit
authors.forename: Francis
authors.initials: F
authors.lastname: Bonnet
mesh_terms: D000556:Ambulatory Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D000775:Anesthesia, Spinal / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D002045:Bupivacaine / Q000008:administration & dosage*; D003627:Data Interpretation, Statistical; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D010149:Postoperative Pain / Q000209:etiology / Q000517:prevention & control
chemical_list: D000779:Anesthetics, Local; D002045:Bupivacaine