DIFFERENT ENDOTRACHEAL-TUBES - CUFF SEAL, INTRATRACHEAL POSITION, ANDPOSTOPERATIVE THROAT COMPLAINTS

The study objective was to evaluate cuff seal, tube tip position and i ncidence of postoperative sore throat in three different endotracheal tubes: the reusable Rusch ''red rubber'' tube (low-volume, high-pressu re cuff) and the disposable Rusch ''Super Safety Clear'' and Mallinckr odt ''lo-pro'' tubes (both high-volume, low-pressure cuffs). Methods. In a prospective randomized trial, 150 consecutive patients scheduled for minor orthopaedic surgery under standardized general anaesthesia, including standardized cuff pressure control, were allocated to one of the three types of endotracheal tube. Leakage and intratracheal tube tip position were investigated by means of fiberoptic tracheoscopy via the endotracheal tube, preceded by pharyngeal instillation of indigoc armine. The semi-standardized interviews for the recording of postoper ative sore throat were performed once a day under double-blind conditi ons from the day of operation to postoperative day 3. Statistical inde pendence testing was based on the chi2-test, significance was assumed at P < 0.05. Main results. A past-cuff leakage of the pharyngeally ins tilled dye was found in three patients with '' red rubber'' tubes. In all of these cases the tracheal cross section deviated markedly from c ircular. The tips of the '' Super Safety Clear '' tubes tended to be b etter centred (P=0.099). Bad tip position, however, had little influen ce on postoperative throat complaints (P=0.394). The differences in in cidence of postoperative throat complaints between the ''red rubber'' (48.9%), ''Super Safety Clear'' (35.6%) and ''lo-pro'' tubes (34.1%) d id not reach the 5% level (P=0.288). Such complaints, however, were si gnificantly more frequent in females and in obese patients who exceede d their Broca weights by more than 25%. By contrast, postoperative thr oat complaints did not vary statistically significantly by age group, tracheal cross-sectional shape, use of atropine or duration of intubat ion. Conclusion. Despite the economic (usable up to 100 times) and eco logical (less PVC waste) advantages of the rubber tube, the disposable tubes with high-volume, low-pressure cuffs tended to be superior rega rding cuff seal, tube tip position and incidence of postoperative thro at complaints. Nevertheless, the continued use of ''red rubber'' type reusable tubes may be justified in cases where the tube has to stay in place for only a short time.