Correspondence  |   April 2009
Two or Three Interviews?
Author Affiliations & Notes
  • Alejandro E. Delfino, M.D.
  • *Pontificia Universidad Católica de Chile, Santiago, Chile.
Article Information
Correspondence   |   April 2009
Two or Three Interviews?
Anesthesiology 4 2009, Vol.110, 950. doi:10.1097/ALN.0b013e31819c47f0
Anesthesiology 4 2009, Vol.110, 950. doi:10.1097/ALN.0b013e31819c47f0
To the Editor:—
We have read with great interest the manuscript by Davidson et al.  , related to the incidence of awareness in a pediatric population. We should congratulate the authors for their effort.1 
They report an incidence of awareness of 0.2%. This value is significantly lower than others studies, including a previous one from the same author.2 
We would like to add some comments to the discussion, and specifically another possible explanation for the lower incidence of awareness.
The authors in this study conducted only two postoperative interviews, at 24 and at 72 hours. They claimed that a third interview at 30 days had low positive findings, although in the previous study by the same authors they conducted three interviews and the last had a positive findings of 29%. Two of the seven reported cases appeared with the third interview.2 The overall incidence of awareness in the pediatric population was 0.8%, over 921, significantly higher than the present study.
The Brice test,3 to our knowledge, seems to be the best methodology to study this complication, with different modifications depending on the population undergoing the study. According to that test, ideally three interviews should be conducted: within 24 hours, between 24 and 72 hours, and at 30 days after surgery.4–5 
In a clinical condition as the one reported, we should ideally follow methodology already validated or at least accepted by current anesthesia practice. In this study, the change in the protocol may be one of the reasons explaining the lower incidence of awareness.
*Pontificia Universidad Católica de Chile, Santiago, Chile.
Davidson AJ, Sheppard SJ, Engwerda AL, Wong A, Phelan L, Ironfield CM, Stargatt R: Detecting awareness in children by using an auditory intervention. Anesthesiology 2008; 109:619–24Davidson, AJ Sheppard, SJ Engwerda, AL Wong, A Phelan, L Ironfield, CM 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
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
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
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