Correspondence  |   July 2007
Impossible Mask Ventilation
Author Notes
  • (Accepted for publication February 22, 2007.)
    (Accepted for publication February 22, 2007.)×
Article Information
Correspondence   |   July 2007
Impossible Mask Ventilation
Anesthesiology 7 2007, Vol.107, 171. doi:10.1097/01.anes.0000268504.03682.8c
Anesthesiology 7 2007, Vol.107, 171. doi:10.1097/01.anes.0000268504.03682.8c
To the Editor:—
I would like to congratulate Dr. Kheterpal et al.1  on their extremely interesting article and Dr. Yentis2  on his perceptive editorial. There are two points I would like to make.
First, when I began my 33 yr (so far) in the practice of anesthesia, obese patients were unusual, but now they are all too common. I am glad I am not starting now; obesity introduces many problems in anesthetic management, and yet, as Dr. Yentis hints, criticizing obese patients and the food industry that supplies them is a political minefield. It will not usually be feasible to decrease a patient's weight before anesthesia, but we should encourage our specialty's representatives to publicize the extra risks involved.
Second, a practice has become fairly firmly established (in the United Kingdom at least) over the past 5 yr or so that one does not give a dose of muscle relaxant until mask ventilation has been demonstrated to be possible (this dictum is ignored when patients require a rapid sequence induction). This practice seems a priori a good idea, but the results of Kheterpal et al. seem to show otherwise. What the results of Kheterpal et al. suggest is that it is only a good idea to delay the introduction of muscle relaxants in those patients who will be easy to mask ventilate. What seems to have saved 36 of the 37 impossible-to-mask-ventilate patients was tracheal intubation. If tracheal intubation is what is required in these patients, the earliest possible introduction of muscle relaxants is presumably the best tactic. Should we go back to the practice of 30 yr ago, when we often gave our nondepolarizing muscle relaxants before the thiopentone, so that we could control the airway as soon as possible? Kheterpal et al. do not say whether muscle relaxants were used to aid intubation in the 37 grade 4 cases, and it would be interesting to know this.
There is “an uneasy combination of science and art in airway management,”3  and much of our practice is based on anecdote and opinion. Dr. Kheterpal et al. have given us some data, for which we should be truly grateful, even though it makes us even less certain of the correct approach.
Ian Calder, F.R.C.A. The National Hospital for Neurology and Neurosurgery, London, United Kingdom.
Kheterpal, S, Han, R, Tremper, KK, Shanks, A, Tait, AR, O'Reilly, M, Ludwig, TA Incidence and predictors of difficult and impossible mask ventilation.. Anesthesiology. (2006). 105 885–91 [Article] [PubMed]
Yentis, SM Predicting trouble in airway management.. Anesthesiology. (2006). 105 871–2 [Article] [PubMed]
Calder, I, Pearce, A Preface, Core Topics in Airway Management.. (2005). Cambridge Cambridge University Press