A number of problems have been reported with the use of standard length tracheostomy tubes in adult critical care patients. We measured the depth from the skin surface to the tracheal wall and the angle of the tracheal stoma during percutaneous tracheostomy. In vitro measurements were also performed on standard tracheostomy tubes. Comparison of in vivo and in vitro dimensions demonstrated that standard length tracheostomy tubes are too short for the average critical care patient. We recommend that both the stomal and intratracheal lengths should be made longer by approximately 1 cm and tubes should be redesigned to an angle of 110-120 degrees to allow optimal tracheal placement.