title: Comparison of surgical stress index-guided analgesia with standard clinical practice during routine general anesthesia: a pilot study.
abstract: BACKGROUND
  Surgical stress index (SSI), a novel multivariate index, has recently been proven to react well to surgical nociceptive stimuli and analgesic drug concentration changes during general anesthesia. We investigated the feasibility of application of SSI for guidance of remifentanil administration during propofol-remifentanil anesthesia.
  
  
  METHODS
  Eighty patients scheduled for elective ear-nose-throat surgery were randomized into two groups, SSI-guided analgesia group (SSI group) and standard practice analgesia group (control group). In both groups, anesthesia was maintained with a propofol target-controlled infusion and adjusted stepwise by 0.5 microg/ml to keep bispectral index values between 40 and 60. In the SSI group, the predicted effect-site concentration of remifentanil was adjusted stepwise by 1 ng/ml to keep SSI values between 20 and 50, whereas in the control group, predicted effect-site concentration of remifentanil was adjusted according to traditional inadequate analgesia criteria. Anesthetics consumption, recovery times, and incidence of unwanted events were recorded.
  
  
  RESULTS
  Remifentanil consumption (average normalized infusion rate) was lower in the SSI group than in the control group (mean +/- SD, 9.5 +/- 3.8 microg . kg(-1) . h(-1) vs. 12.3 +/- 5.2 microg . kg(-1) . h(-1); P < 0.05). The number of unwanted events was less in the SSI group (84) than in the control group (556; P < 0.01). Recovery times were comparable between groups. No patient reported intraoperative recall.
  
  
  CONCLUSIONS
  SSI-guided anesthesia resulted in lower remifentanil consumption, more stable hemodynamics, and a lower incidence of unwanted events.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Germany.
authors.forename: Xinzhong
authors.initials: X
authors.lastname: Chen
authors.forename: Carsten
authors.initials: C
authors.lastname: Thee
authors.forename: Matthias
authors.initials: M
authors.lastname: Gruenewald
authors.forename: Jan
authors.initials: J
authors.lastname: Wnent
authors.forename: Christoph
authors.initials: C
authors.lastname: Illies
authors.forename: Jan
authors.initials: J
authors.lastname: Hoecker
authors.forename: Robert
authors.initials: R
authors.lastname: Hanss
authors.forename: Markus
authors.initials: M
authors.lastname: Steinfath
authors.forename: Berthold
authors.initials: B
authors.lastname: Bein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000698:Analgesia / Q000295:instrumentation / Q000379:methods*; D000768:Anesthesia, General / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D010865:Pilot Projects; D013312:Stress, Physiological; D013514:Surgical Procedures, Operative / Q000379:methods*; D055815:Young Adult