A reply

Abstract

We thank Dr Greenland for interest in our paper. In answer to the first question, we confirm that all our failures with the Berman airway occurred in females, in whom we used the size 8 or 9 airway. So, our experience does not, by itself, support Greenland's (intuitively persuasive) suggestion that the size 10 airway should cause the most difficulty. However, our observation should not be taken as definitive as there was a preponderance of females in our study (see Table 1 of our paper): indeed for this reason, we were careful not to undertake extensive subgroup analysis. It is very difficult for us to answer Greenland's second question asking us to clarify the level (for example the epiglottis or tongue) at which ‘failure to view the vocal cords’ occurred. All operators found that the anatomy as viewed through the fibrescope on emerging from the end of the Berman airway was often unclear, compared with the very clear view obtained with jaw thrust. Expressed another way: had operators known exactly where the tip of the fibrescope was on emerging from the tip of the Berman airway, they should have been in a position to negotiate their route to the vocal cords. We summarise the problem, therefore, as one of a generally poor view at the end of the airway, rather than one of a specific obstruction to a clear view. This is something which we think is very difficult to express in any subjective scoring system, but is better reflected in measuring objectively the time taken to view the vocal cords. We might add that the efficacy of the jaw thrust manoeuvre can be demonstrated by releasing it mid-endoscopy: the adverse change in view is dramatic and usually results in complete loss of any recognisable structure. Finally, we concur with Greenland's points relating to other airways and the need for studies to help choose the proper size.