Tracheostomy is considered the airway management of choice for patients who require prolonged mechanical ventilation. The development of percutaneous techniques offers many advantages including the ability to perform the procedure in the intensive care unit. The aim of this study was to compare the controlled rotating dilation method (PercuTwist) and the Griggs' forceps dilational tracheostomy. Patients over 18 years of age undergoing tracheostomy in the intensive care unit were included in the study. They were divided in two random samples--either PercuTwist or forceps dilational tracheostomy. Data collected prospectively included demographic characteristics, procedure duration, blood gas analysis, intracranial pressure, arterial blood pressure and heart rate before and after the procedure. Any complications during or after the procedure due to the tracheostomy were also recorded. Contrary to the main hypothesis, PercuTwist technique took significantly longer to perform than forceps dilational tracheostomy technique (five minutes [2 to 25] vs three minutes [1 to 17][P=0.006]). A significant increase in P(a)CO2 and decrease in arterial pH were observed in both groups between the pre-tracheostomy and post-tracheostomy blood gas analysis. Haemodynamic tolerance was good. Our results show that intracranial pressure is affected by the procedure whatever the technique used. However we did not observe a decrease in cerebral perfusion pressure. The incidence of complications was 23% (20/87). These complications were minor in 18/20 and were not significantly different between the two groups. In conclusion, we consider that the PercuTwist technique is safe despite the longer duration of the procedure. Nevertheless the forceps dilational technique remains our routine procedure.