title: Awareness during emergence from anaesthesia: significance of neuromuscular monitoring in patients with butyrylcholinesterase deficiency.
abstract: BACKGROUND
  Butyrylcholinesterase deficiency can result in prolonged paralysis after administration of succinylcholine or mivacurium. We conducted an interview study to assess whether patients with butyrylcholinesterase deficiency were more likely to have experienced awareness during emergence from anaesthesia if neuromuscular monitoring had not been applied.
  
  
  METHODS
  Patients referred during 2004-2012 were included. Data on the use of neuromuscular monitoring were available from a previous study. Interviews, conducted by telephone, included questions about awareness and screening for post-traumatic stress disorder. Reports of panic, hopelessness, suffocation, or a feeling of being dead or dying resulted in the experience being classified further as distressful. Patients were categorized as aware or unaware by investigators blinded to use of neuromuscular monitoring.
  
  
  RESULTS
  Ninety-five patients were eligible to be interviewed. Of the 70 patients interviewed, 35 (50%) were aware while paralysed during emergence. Of these, 28 (80%) were not monitored with a nerve stimulator when awakened, compared with 17 (49%) of the 35 unaware patients (P=0.012, Fisher's exact test). Thirty (86%) aware patients reported distress compared with seven (20%) unaware patients (P<0.001). The aware patients scored higher in screening for post-traumatic stress disorder (P=0.006, Mann-Whitney U-test).
  
  
  CONCLUSIONS
  Butyrylcholinesterase deficiency is a major risk factor for distressing awareness during emergence. Lack of neuromuscular monitoring increases the risk significantly. Neuromuscular monitoring should be applied even when using short-acting neuromuscular blocking agents.
authors.affiliation: Danish Cholinesterase Research Unit, Department of Anaesthesiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark jakob.louis.thomsen@regionh.dk.
authors.forename: J L
authors.initials: JL
authors.lastname: Thomsen
authors.affiliation: Danish Cholinesterase Research Unit, Department of Anaesthesiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark.
authors.forename: C V
authors.initials: CV
authors.lastname: Nielsen
authors.affiliation: Danish Cholinesterase Research Unit, Department of Anaesthesiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark.
authors.forename: K Z
authors.initials: KZ
authors.lastname: Eskildsen
authors.affiliation: Danish Cholinesterase Research Unit, Department of Anaesthesiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark.
authors.forename: M N
authors.initials: MN
authors.lastname: Demant
authors.affiliation: Danish Cholinesterase Research Unit, Department of Anaesthesiology, Herlev Hospital, University of Copenhagen, Herlev, Denmark.
authors.forename: M R
authors.initials: MR
authors.lastname: Gätke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001049:Apnea; D002091:Butyrylcholinesterase / Q000172:deficiency*; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D058926:Intraoperative Awareness; D008297:Male; D008661:Metabolism, Inborn Errors / Q000503:physiopathology*; D008875:Middle Aged; D061886:Neuromuscular Monitoring; D010243:Paralysis / Q000209:etiology; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis
chemical_list: D002091:Butyrylcholinesterase
keywords: anaesthesia awareness; butyrylcholinesterase deficiency; neuromuscular block; neuromuscular monitoring