A NEW TRACHEAL TUBE FOR DIFFICULT INTUBATION

We have compared a new Porter tracheal tube with the Oxford tube in pe rforming simulated grade 3 difficult intubations. The Pouter tube was modified so that the bevel faced backwards, as in the Oxford tube. A g um elastic introducer was used with both tubes. The time taken and num ber of attempts needed were recorded, with changes in arterial pressur e, heart rate and incidence of sore throat. Both tubes were successful in avoiding the problem of obstruction at the cords, which occurs whe n a standard Magill tube is used with an introducer. Thus the new tube has the merits of the Oxford tube without the disadvantages of rubber . It is suitable for both easy and difficult intubations with advantag es in safety, cost and convenience. An unexpected but important findin g was a clear learning effect, despite both investigators being famili ar with the technique at the outset. Over the course of the study, int ubation time decreased progressively (P < 0.001). This provides new ev idence of the need for trainees to practise the art of intubation when the cords are not visible. Our estimate of the learning ''half-life'' was 15 intubations; we conclude that 30 simulated grade 3 intubations would be a reasonable objective for trainees before handling high-ris k cases.