Tracheostomy is a widely performed procedure in critically ill patients requiring long-term ventilatory support. The standard surgical tracheostomy technique was first described by Jackson in 1909 . However, this technique is associated with the risks of transportation of the patients to the operating room and problems in operating theatre schedules. These led to the development of newer techniques that can be easily performed at the bedside.
Percutaneous tracheostomy was first described by Shelden and colleagues  in 1957. Ciaglia and colleagues described the percutaneous dilatational tracheostomy (PDT) technique by means of a series of dilatators in 1985  and Griggs and colleagues reported on the guide-wire dilating forceps (GWDF) technique in 1990 . Recently, the controlled rotating dilatation method (PercuTwist) was described as a new technique .
Although there exist many reports comparing the techniques of Griggs and Ciaglia, there is no study comparing all three techniques including the PercuTwist.
This clinical study was performed in our medical-surgical intensive care unit (ICU). One hundred and thirty patients requiring endotracheal intubation for more than 10 days due to acute respiratory stress syndrome, infections or cerebrovascular events were consecutively selected to undergo one of the PDT, GWDF or PercuTwist techniques. Patients with any of the following criteria were excluded from the study: (1) prior tracheostomy, (2) haemorrhagic disorders (platelet count < 50 000, prothrombin international normalized ratio >2 or activated partial thromboplastin time >1.5 times the control value), (3) marked anatomic abnormalities of the trachea or cervical region (including very short neck), (4) clinical evidence of infection at the trachea puncture site and (5) the need for an emergency airway. None of the patients were obese (BMI > 30).
Institutional Ethic Committee approval and written informed consent were taken from all patients or relatives. The three groups were as follows: Ciaglia' s dilatation technique with multiple dilatator group (PDT group; n = 44), Griggs' GWDF group (GWDF group; n = 41) and PercuTwist group (n = 45). All tracheostomies were performed at the bedside in the ICU under general intravenous (i.v.) anesthesia using propofol, fentanyl and pancuronium by the same two anaesthesiologists having similar degrees of experience and skills. These anaesthesiologists had been working in the ICU for 3 yr. In our ICUs, we perform >60 percutaneous tracheostomies per year, and Ciaglia's dilatation technique and GWDF technique both had been used routinely before the beginning of the study. The anaesthesiologists and the techniques were numbered. Cards having these numbers were prepared and were put into sealed envelopes and patients were randomized by these cards.
Before the procedure started, FiO2 was increased to 1.0 and controlled positive pressure ventilation was established and continued throughout the procedure. Additionally, electrocardiogram, invasive blood pressure and pulse oximetry were continuously monitored. The patient's neck was slightly reclined, and the surgical area was cleaned and prepared with surgical drapes in the typical manner. A flexible fibreoptic bronchoscope was used in every case. In the PercuTwist group, the PercuTwist Set with a 9.0 mm internal diameter PercuQuick tracheostomy cannula (Rüsch GmbH, Kennen, Germany) was used. To facilitate access to the trachea, the tracheal tube was withdrawn under direct laryngoscopy to the level of the glottic opening. After identification of the anatomical landmarks, the puncture cannula was advanced through the anterior wall of the trachea, generally between the first and second or second and third tracheal rings and positioned centrally in the midline of the trachea. Once the cannula was positioned in the trachea, the syringe and the metal guide-wire were removed. The J-tipped guide-wire was advanced caudally through the indwelling cannula and a skin incision approximately 3–4 mm long on both sides was made. After activation of the hydrophilic coating of the PercuTwist dilator, it was advanced over the guide-wire by rotating the dilator clockwise. Once the anterior tracheal wall was cut by the dilator and was endoscopically seen, the dilation was continued by gentle elevation of the anterior tracheal wall with the dilator while screwing it further intratracheally under endoscopic vision. After that the dilator was removed by rotating it in a counter clockwise direction and the guide-wire was left in the trachea. The tracheostomy cannula was then placed over the guide-wire using Seldinger's technique. Once the tracheostomy tube position was confirmed endoscopically, the guide-wire and the introducer were removed.
In the GWDF group, the Portex-kit (SIMS Portex; Kent, UK) was used. The trachea was entered between the tracheal rings with an i.v. catheter, seen by bronchoscopy. The guide-wire was threaded through the catheter. After that, the sharp-tipped dilating forceps was passed over the wire, spread in the skin and soft tissues, then into the trachea and spread again. Once this route was created, the tracheostomy cannula was placed over the guide-wire under bronchoscopic vision. For the PDT group, Ciaglia multiple dilatator kit (Ciaglia Tracheostomy Introducer Set; William Cook Europe, Bjaeverskov, Denmark) was used. After placement of a J-tipped guide-wire between the tracheal rings towards the carina, a series of stiff plastic dilators were sequentially forced into the tracheal wall over the guide-wire until a stoma, large enough for the tracheostomy cannula, had been created. Once the stoma had been created, a tracheostomy tube was introduced into the trachea over the same guide-wire using one of the dilators as a guide.
After placement of the tracheostomy tube with any of the methods, tracheal suction was performed, the tracheal cuff was inflated with air and ventilation of the patient's lungs was resumed through the tracheostomy tube. The time taken to perform the procedure (skin incision to successful placement of the tracheostomy tube) was noted. Complications were defined as follows: hypoxia (SPO2 < 90%), hypercarbia (>5 mmHg increase in PaCO2 from the baseline), hypotension (>20% decrease in systolic pressure), hypertension (>20% increase in systolic pressure), technical difficulties, subcutaneous emphysema, procedural mortality (mortality directly related to a technique complication, during the procedure or later during the stay in the ICU), tracheal tear (a tear produced over the tracheal wall during the procedure), tracheal stenosis, false passage (dilatation or insertion of the cannula outside the tracheal lumen), tracheo-oesophageal fistula and bleeding classified  as (1) absent or minimal (bleeding requiring no intervention), (2) medium (need for special wound dressing and/or vasoactive drugs) or (3) serious (requiring surgical intervention). Tracheostomy site infection was considered when breakdown of the incision or cellulitis developed in association with purulent secretion.
On the first postoperative day (within 24 h following the procedure), all patients had undergone fibreoptic bronchoscopy routinely by a blinded thoracic surgeon without decannulation of the patient, and injuries to the trachea were studied. Patients who developed complications required additional bronchoscopies. Six months after the procedure, one of the authors called the patients and asked whether the patient had symptoms including hoarseness, subjective voice change or feeling of a foreign body in the larynx.
Data were analysed using the Statistical Package for the Social Sciences Software for Windows (SPSS Inc., Chicago, IL, USA). Quantitative variables are described as mean ± SD and range when appropriate. Categorical variables are expressed as percentages. Comparisons between means were performed with the t-test and those between percentages with the χ2-test. Sample size was calculated as follows. Based on the literature, a significant difference was expected with respect to procedure times between the PercuTwist and the other two groups. For the PDT group the study of Johnson and colleagues  was taken as a reference, for the PercuTwist group the study by Westphal and colleagues  was taken as a reference and for the GWDF group the study by Fikkers and colleagues  was taken as a reference. Depending on the procedure times reported in these studies, statistical power analysis using α = 0.05 and β = 0.2 indicated that a total of 120 observations would be needed to detect a significant difference in procedure times with a power of 80%.
One hundred and thirty patients were enrolled in this study, 44 for PDT, 41 for GWDF and 45 for PercuTwist. The patient characteristics and medical historical data, as well as acute physiology and chronic health evaluation scores (APACHE II), were comparable between the groups (Table 1).
The operating times were 9.9 ± 1.1, 6.2 ± 1.4 and 5.4 ± 1.2 min in the PDT, GWDF and PercuTwist groups, respectively. The duration of the procedure was significantly shorter in the PercuTwist group as compared to the PDT (P < 0.01) and GWDF (P < 0.05) groups. In addition to this, procedure duration was also shorter with GWDF as compared to PDT (P < 0.05). Postoperative bronchoscopy revealed eight cases of longitudinal tracheal abrasion (four in the PDT group, two in the GWDF group and two in the PercuTwist group), two cases of posterior tracheal wall injury (one in PDT and one in GWDF) and one case of tracheal ring rupture (PDT group). There were no incidences of airway obstruction, bronchospasm, paratracheal insertion, pneumomediastinum, pneumothorax, hypoxia, hypercarbia, hypotension or subcutaneous emphysema. All cardiac arrhythmias were new onset, sinus tachycardia or ventricular extrasystoles. No treatment was given for them. All instances of bleeding were Grade I and controlled by pressure application. The four cases of difficult dilation occurred at varying points during the procedure and all of them were due to too small a skin incision. Of the four cases with difficult dilation, one patient had tracheal ring rupture diagnosed on the control bronchoscopy and was treated conservatively as there was no additional complication such as pneumothorax or haemorrhage. This patient subsequently developed tracheal stenosis diagnosed by conventional tracheoscopy on the first month follow-up visit due to symptoms of dyspnoea. Two patients with posterior tracheal wall injury on postoperative broncoscopy developed a tracheo-oesophageal fistula. They did not undergo immediate repair due to their poor general medical condition. One of them died during the hospital stay due to septic shock and the other underwent a tracheal stent placement procedure and was eventually discharged. Complications are shown in Table 2.
One hundred and eight patients were succesfully decannulated during their hospital stay. Twenty-two patients died cannulated as a result of their underlying disease or its complications. Survivors were followed up after discharge; 101 patients survived and authors were able to reach 79 of them. None of the mortality was attributable to the procedure. Of the survivors, 29, 27 and 23 were in the PDT, GWDF and PercuTwist groups, respectively. Four patients in the PDT, three in the GWDF and three in the PercuTwist groups reported mild hoarseness. In addition, three patients in the PDT, two in the GWDF and two patients in the PercuTwist groups had a feeling of foreign body sensation.
Percutaneous tracheostomy techniques are widely used in many ICUs in patients requiring long-term mechanical ventilation. The advantages of this technique include a small skin incision with less tissue dissection, less time consumption and the facility to perform this procedure in the ICU. Several studies have shown that, in addition to decreased procedure time, a percutaneous technique is associated with lower complication rates than surgical tracheostomy [9-11].
Although a number of percutaneous techniques have been introduced in the past two decades, the techniques of Ciaglia and colleagues  and Griggs and colleagues  are the most common ones being used [12-14]. Recently, a new technique with one-step dilation has become available, the PercuTwist tracheostomy set . The PercuTwist technique is increasingly used as a new PDT technique. Despite the technical differences, all percutaneous methods consist of initial puncture of the trachea followed by dilation up to the degree required for tracheal cannula positioning. The dilation might be achieved by multiple or single dilators, the latter technique being reported to be associated with fewer complications than the multiple dilator method [15,16]. However, airway loss, serious bleeding, pneumothorax, injury to the posterior tracheal wall and tracheal stenoses have been reported with both single and serial dilators [3,17]. Reports with the PercuTwist technique are preliminary and few. This study is the first randomized, prospective, controlled trial comparing these three percutaneous tracheostomy techniques.
The duration of procedure starting from skin incision to the successful placement of the cannula in the PercuTwist group at 5.4 ± 1.2 min is significantly lower than both PDT and GWDF groups (9.9 ± 1.1 and 6.2 ± 1.4 min, respectively). This is in agreement with three previous studies [5,7,18], although none of those were controlled prospective studies. For any technique, as well as the time it takes, the complication rate is also important. In our study, none of the serious complications such as tracheal ring rupture and tracheo-oesophageal fistula occurred in the PercuTwist group. Tracheal ring rupture is a well-recognized complication of percutaneous tracheostomy and is easily recognized by the use of fibreoptic bronchoscopy. In the literature, its incidence is reported to be between 2% and 9% in studies using other techniques . Roberts and colleagues  and Scherrer  reported tracheal ring fracture after PercuTwist tracheostomy during the dilation process. Antegrade forces should be minimized and skin incision should be deep and large enough to avoid this complication. The PercuTwist technique is unique in this aspect by lifting the anterior tracheal wall during dilatation with the help of the screw-like device. Additionally, the opening created by the screw in PercuTwist has less tendency to close after the removal of the dilator than other techniques . In our study, one of the four patients with difficult dilation had tracheal ring fracture and was in the PDT group. He subsequently developed tracheal stenosis. However, as we did not use radiological imaging, we did not calculate the tracheal luminal area. Thus, the term tracheal stenosis is based only on the clinical and bronchoscopic findings, which are often inadequate. This is one of the limiting factors of the present study.
Posterior tracheal wall injury is a serious complication and has been reported with percutaneous techniques [8,21]. The force applied to the anterior tracheal wall and compression of the anterior wall posteriorly may be the mechanism of this complication. The downward direction of dilation during PDT can cause significant compression of the anterior tracheal wall towards the posterior wall. This complication seems to be unlikely in the PercuTwist technique because of the antegrade screwing of the dilator by simultaneous elevation of the anterior tracheal wall during the procedure. Because of the dilator's screw-tap design, access to the trachea is possible without the need for excessive pressure towards the posterior tracheal wall, and the wet coat covering the dilator reduces friction during the dilation process in the PercuTwist technique. However, pressure still has to be exerted on the trachea until the dilator catches hold between the tracheal rings. Additionally, Westphal and colleagues  reported that, because the degree of dilation is larger and the loading dilator fits more closely to the tracheal cannula, less strength is required to insert the tracheal cannula with the PercuTwist technique. None of the two patients in this study who suffered from this complication and developed tracheo-oesophageal fistula were in the PercuTwist group. Posterior tracheal wall injury was reported to be easier in the GWDF method [14,22].
In this study, the most frequent complication was bleeding. It was common in the PDT and GWDF groups. The number of patients having this complication was highest in the PDT group. Our results are in contrast to those from Nates and colleagues . They found the highest bleeding rate in the Griggs method in a prospective, randomized study comparing Ciaglia and Griggs techniques. All haemorrhages were Grade I and stopped by pressure application in our study. By avoiding multiple dilator changes, the PercuTwist technique exposes the lower airways to bleeding and obstruction less than conventional PDT. Postoperative bronchoscopic examination did not identify any endotracheal bleeding. One might argue that bronchoscopy was performed without decannulation of the patient, but we believe that it would be dangerous following a recently placed tracheostomy. Our preference of performing bronchoscopy via the cannula is similar to the work carried out by Sengupta and colleagues .
The present study is, to our knowledge, the first one comparing three different percutaneous tracheostomy techniques, including PercuTwist. If studies evaluating the PercuTwist method are taken into consideration, the present one is one of the largest. Although one may argue that it would be more appropriate to compare the PercuTwist and Ciaglia Blue Rhino technique instead of PDT, as Ciaglia Blue Rhino is not one of our routine techniques, we believe that comparing these three techniques made more sense.
In conclusion, the PercuTwist-controlled rotating dilatation method has an acceptable complication rate and also takes a shorter time to perform than the PDT and GWDF methods. Thus, we believe that the PercuTwist technique is easy to perform and a practical alternative to the PDT and GWDF techniques.
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