THE USE OF BROMOTHYMOL BLUE AND SODIUM THIOPENTONE TO CONFIRM TRACHEAL INTUBATION

The possibility of using chemical changes to confirm correct tracheal tube placement was investigated with a view to their use in developing countries where mole sophisticated methods ale unavailable. The effec t of bubbling expired gases through a 10% solution of bromothymol blue and a 0.25% solution of thiopentone led to chemical changes producing , in rite case of bromothymol blue, a colour change and in that of thi opentone, precipitation, probably due to a change in pH caused by carb on dioxide. We also discovered that the lime to precipitation of the t hiopentone could be greatly reduced if it was mixed with a precise qua ntity of lignocaine. These simple end points can reliably confirm the correct placement of a tracheal tube at least as rapidly as the correc t use of capnography.