title: General anesthesia occurs frequently in elderly patients during propofol-based sedation and spinal anesthesia.
abstract: OBJECTIVE
  To test the hypothesis that sedation in elderly patients is often electrophysiologically equivalent to general anesthesia (GA).
  
  
  METHODS
  Prospective, observational study.
  
  
  METHODS
  Operating room of a university medical center.
  
  
  METHODS
  40 elderly patients (>or=65 yrs of age) undergoing hip fracture repair with spinal anesthesia and propofol-based sedation.
  
  
  METHODS
  In the routine practice group (RP; n = 15), propofol sedation was administered per the usual routine of the anesthesiologist. In the targeted sedation group (TS; n = 25), sedation was titrated to an observer's assessment of alertness/sedation (OAA/S) score of 4 (ie, lethargic in response to name called) to 5 (ie, awake and alert).
  
  
  METHODS
  Both patient groups underwent processed electroencephalographic monitoring using bispectral index (BIS) intraoperatively. BIS levels were compared between groups to determine amount of surgical time spent in GA (BIS <or= 60).
  
  
  RESULTS
  In the RP group, subjects spent 32.2% of surgical time at BIS levels consistent with GA. Although averaged BIS values during surgery increased from (mean +/- SD) 71 +/- 16 to 88 +/- 9 (P < 0.001), GA was still observed during 5% of surgical time in the TS group. Overall, 13 of 15 (87%) RP group patients and 11 of 25 (44%) TS group patients (P < 0.010) experienced some period of GA.
  
  
  CONCLUSIONS
  BIS levels consistent with GA occur frequently in elderly patients during propofol-based sedation for spinal anesthesia. Altering routine practice such that sedation is titrated to a targeted clinically-determined sedation level reduces - but does not eliminate - this incidence.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Bayview Medical Center, Baltimore, MD 21224, USA. fsieber@jhmi.edu
authors.forename: Frederick E
authors.initials: FE
authors.lastname: Sieber
authors.forename: Allan
authors.initials: A
authors.lastname: Gottshalk
authors.forename: Khwaja J
authors.initials: KJ
authors.lastname: Zakriya
authors.forename: Simon C
authors.initials: SC
authors.lastname: Mears
authors.forename: Hochang
authors.initials: H
authors.lastname: Lee
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General; D000775:Anesthesia, Spinal / Q000379:methods; D018686:Anesthetics, Intravenous; D016292:Procedural Sedation / Q000379:methods*; D004569:Electroencephalography; D005260:Female; D006620:Hip Fractures / Q000601:surgery; D006801:Humans; D008297:Male; D015742:Propofol; D011446:Prospective Studies
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol