title: AAI-guided anaesthesia is associated with lower incidence of 24-h MMSE < 25 and may impact the IL-6 response.
abstract: BACKGROUND
  Trauma stress and neuro-inflammation caused by surgery/anaesthesia releases cytokines. This study analysed impact of Auditory Evoked Potential Index (AAI) depth-of-anaesthesia titration on the early plasma IL-6 release after eye surgery under general anaesthesia.
  
  
  METHODS
  This is a subgroup analysis of a prospective randomized study on the effect of auditory evoked potential guided anaesthesia for eye surgery. Plasma IL-6 levels taken before, 5 and 24 h after end of surgery from 450 patients undergoing elective ophthalmic surgery under desflurane anaesthesia were analysed. Minimal mental state examination (MMSE) was also tested at 24-h.
  
  
  RESULTS
  IL- 6 increased significantly at both 5 and further at 24 h after surgery (3.2, 4.5 and 5.1 base-line, 5 and 24-h respectively), the IL-6 increase showed different patterns between the 2 groups; IL-6 was significantly increased in the control group of patients between preoperative baseline and 24 h after surgery (p = 0.008) also between 5 h and 24 h, (p = 0.006) after surgery while the AAI-group had only minor non-significant changes. The 18 patients that showed a 24-h MMSE score less than 25 had a significant higher 24-h IL-6 compared to the 390 patients with a MMSE score > 24 (p = 0.002).
  
  
  CONCLUSIONS
  The IL-6 increase after surgery was less pronounced in patients where anaesthesia was titrated by AAI compared to anaesthesia adjusted on clinical signs only. IL-6 were also found to be higher in patients with a MMSE < 25 at 24-h. Further studies are warranted evaluating the role of depth of anaesthesia monitoring on the risk for early cognitive impairment and neuro-inflammation.
  
  
  BACKGROUND
  Clinicaltrials.gov identifier: NA/study were conducted between January 2005-April 2008.
authors: Department of Anaesthesiology and Intensive Care, University Hospital, Örebro, Sweden.
authors: Pether K
authors: PK
authors: Jildenstål
authors: Department of Anaesthesiology and Intensive Care, University Hospital, Örebro, Sweden.
authors: Jan L
authors: JL
authors: Hallén
authors: Department of Anaesthesiology and Intensive Care, University Hospital, Örebro, Sweden.
authors: Narinder
authors: N
authors: Rawal
authors: Department of Anaesthesiology and Intensive Care, University Hospital, Örebro, Sweden; CAMTÖ, Centre for Assessment of Medical Technology in Örebro, Sweden.
authors: Lars
authors: L
authors: Berggren
authors: Department of Anaesthesiology and Intensive Care, Institution for Clinical Science at The Karolinska Institutet, Danderyds University Hospital, 182 88 Stockholm, Stockholm, Sweden. Electronic address: jan.jakobsson@ki.se.
authors: Jan G
authors: JG
authors: Jakobsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures / Q000379:methods*; D011183:Postoperative Complications / Q000097:blood / Q000517:prevention & control; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D015850:Interleukin-6
keywords: Auditory evoked potential (AEP) monitoring; Cognitive decline; General anaesthesia; IL-6; Minor surgery