The effects of cuffed endotracheal tubes on the tracheal wall.

Direct tracheoscopy was employed to assess tracheal damage following prolonged intubation. Comparison of conventional and low-pressure cuffs showed that there was less trauma from the low-pressure cuff. Comparison of tube sizes showed a reduction in injury with 8-mm diameter tubes compared with larger ones. Knowledge of tracheal damage following prolonged endotracheal intubation has depended hitherto upon analysis of retrospective evidence, postmortem specimens and animal experimentation. The opportunity was taken to compare the effects of standard cuffed Portex Blue-line tubes with those of lowpressure (floppy) cuffs using a fibreoptic laryngoscope. The tubes were all made of the same material and had been sterilized with ethylene oxide by the manufacturers. The object of the present study was to utilize a technique which would enable the observer to visualize the tracheal mucosa at the time of extubation. The patients in this series were undergoing cardiopulmonary bypass surgery, and were ventilated (IPPV) for an average of 15 hours. All patients returned to the intensive care unit after operation, accurate records of their cardiovascular state and drug administration being available for retrospective analysis.