title: The association of plasma gamma-aminobutyric acid concentration with postoperative delirium in critically ill patients.
abstract: OBJECTIVE
  Delirium is a common complication in postoperative, critically ill patients. The mechanism of postoperative delirium is not well understood but many studies have shown significant associations between benzodiazepine use, alcohol withdrawal and cirrhosis, and an increased risk of delirium. We aimed to investigate a possible link with alterations of gamma-aminobutyric acid (GABA) activity.
  
  
  METHODS
  A prospective observational investigation of 40 patients > 20 years old who had undergone elective surgery with general anaesthesia and were expected to need postoperative intensive care for more than 48 hours. We assessed postoperative delirium using the confusion assessment method in the intensive care unit at 1 hour after the operation and on postoperative Day (POD) 1 and POD 2. We collected blood samples for measurement of plasma GABA concentrations before the operation and on POD 1 and 2.
  
  
  METHODS
  Postoperative delirium and perioperative plasma GABA concentrations in patients with and without delirium.
  
  
  RESULTS
  Postoperative delirium occurred in 13 of the patients. Patients with delirium had significantly higher Acute Physiology and Chronic Health Evaluation II scores than patients without delirium. The mean plasma GABA concentration on POD 2 was significantly lower in patients with delirium than in those without delirium. After adjustment of relevant variables, plasma GABA concentration on POD 2 was independently associated with postoperative delirium.
  
  
  CONCLUSIONS
  Plasma GABA level on POD 2 has a significant independent association with postoperative delirium.
authors.affiliation: Department of Anesthesiology and Resuscitology, Okayama University Medical School, Okayama, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Yoshitaka
authors.affiliation: Department of Anesthesiology and Resuscitology, Okayama University Medical School, Okayama, Japan.
authors.forename: Moritoki
authors.initials: M
authors.lastname: Egi
authors.affiliation: Department of Anesthesiology and Resuscitology, Okayama University Medical School, Okayama, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kanazawa
authors.affiliation: Department of Anesthesiology and Resuscitology, Okayama University Medical School, Okayama, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Toda
authors.affiliation: Department of Anesthesiology and Resuscitology, Okayama University Medical School, Okayama, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Morita
mesh_terms: D016638:Critical Illness; D003693:Delirium / Q000097:blood* / Q000503:physiopathology; D006801:Humans; D015999:Multivariate Analysis; D011183:Postoperative Complications / Q000097:blood* / Q000503:physiopathology; D011446:Prospective Studies; D005680:gamma-Aminobutyric Acid / Q000097:blood*
chemical_list: D005680:gamma-Aminobutyric Acid