Correspondence  |   April 2009
Two or Three Interviews?
Author Notes
  • Royal Children's Hospital, Murdoch Children's Research Institute, and University of Melbourne, Melbourne, Australia.
Article Information
Correspondence   |   April 2009
Two or Three Interviews?
Anesthesiology 4 2009, Vol.110, 950-951. doi:
Anesthesiology 4 2009, Vol.110, 950-951. doi:
In Reply:—
I wish to thank Dr. Delfino for his comments. I agree that not having an interview at 1 month may have increased the false negative rate; however, I believe this is unlikely to have made a substantial difference to our result.1 In children, the proportion of cases of awareness first detected at 1 month is appreciable but not large. In our earlier study we detected 2 of the 7 at 1 month, and Lopez et al.  detected one of their 5 confirmed cases at 1 month, while at 1 month Blusse et al.  detected no extra cases of true awareness.2–4 A 25–30-percent increase would not have changed our overall finding of a lower rate of awareness. It should also be noted that adhering to three interviews may result in an increase in false positives, as there is good evidence to suggest that repeated questioning increases implanted memory in children.
Dr. Delfino raises the very important point of validity of awareness assessment. We have found 76 papers describing awareness under anesthesia. Authors describe all sorts of different numbers, timing, and design of interviews. There is no single accepted methodology, and certainly none has been validated; indeed, it is difficult to see how one can be validated. Could it be that the variation in methods used implies that no method is clearly the best? Interestingly many people claim to use the Brice study design, although their study design bears little resemblance to his (Brice played auditory stimuli during anesthesia and interviewed the patients three times in hospital within the first week5). Similarly, the questions Brice used have been modified. The phrase “Brice interview” is becoming meaningless, as increasingly authors use appropriately different and improved study designs and interviews.
I agree that by using the same measure researchers can better understand the etiology of awareness and better compare interventions. However, current measures are still too subjective. Even the measures described by Myles et al.  6 and Avidan et al.  7 rely on subjective ratings by adjudicators. We should not yet accept any awareness assessment method as a gold standard, but continue to seek more accurate ways to measure this important phenomenon.
Royal Children's Hospital, Murdoch Children's Research Institute, and University of Melbourne, Melbourne, Australia.
Davidson AJ, Sheppard S, Engwerda A, Wong A, Phelan L, Ironfield C, Stargatt R: Detecting awareness in children by using an auditory intervention. Anesthesiology 2008; 109:619–24Davidson, AJ Sheppard, S Engwerda, A Wong, A Phelan, L Ironfield, C Stargatt, R
Davidson AJ, Huang GH, Czarnecki C, Gibson MA, Stewart SA, Jamsen K, Stargatt R: Awareness during anesthesia in children: a prospective cohort study. Anesth Analg 2005; 100:653–61Davidson, AJ Huang, GH Czarnecki, C Gibson, MA Stewart, SA Jamsen, K Stargatt, R
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Brice DD, Hetherington RR, Utting JE: A simple study of awareness and dreaming during anaesthesia. Br J Anaesth 1970; 42:535–42Brice, DD Hetherington, RR Utting, JE
Myles PS, Leslie K, McNeil J, Forbes A, Chan MT: Bispectral index monitoring to prevent awareness during anaesthesia: the B-Aware randomised controlled trial. Lancet 2004; 363:1757–63Myles, PS Leslie, K McNeil, J Forbes, A Chan, MT
Avidan MS, Zhang L, Burnside BA, Finkel KJ, Searleman AC, Selvidge JA, Saager L, Turner MS, Rao S, Bottros M, Hantler C, Jacobsohn E, Evers AS: Anesthesia awareness and the bispectral index. N Engl J Med 2008; 358:1097–108Avidan, MS Zhang, L Burnside, BA Finkel, KJ Searleman, AC Selvidge, JA Saager, L Turner, MS Rao, S Bottros, M Hantler, C Jacobsohn, E Evers, AS