A comparison of two single dilator percutaneous tracheostomy sets: the Blue Rhino™ and the Ultraperc™
Summary
The single tapered dilator kit is the most commonly used percutaneous tracheostomy set in the UK. The Cook Blue Rhino™ and the Portex Ultraperc™ were compared in the laboratory on mannequin and porcine airway models. The following data were collected: the subjective ease of dilating the trachea and inserting the tracheostomy tube; the time taken and the anterior–posterior compression during dilatation and tube insertion; the incidence and extent of posterior tracheal wall damage. During dilatation, the Blue Rhino™ caused less mean percentage anterior–posterior compression (34.8% vs. 51.5%, p = 0.0014). There was no difference in subjective ease or time for dilatation in either mannequin or porcine airway models. During insertion of the tracheostomy tube, the Ultraperc™ was subjectively easier in the porcine airway model (p = 0.001); had a shorter median insertion time in both the mannequin (3 s vs. 7.2 s, p = 0.0006) and the porcine airway model (4.3 s vs. 8.5 s, p = 0.0005); the mean percentage anterior–posterior compression caused was less in the mannequin (51.5% vs. 76%, p = 0.0008). The overall incidence of posterior wall damage was 65% with 25% having deep lacerations. There was no difference in the incidence of damage between the two sets. The Ultraperc™ therefore has advantages during tracheostomy tube insertion that are statistically and clinically significant. The advantages are probably due to the presence of the tracheostomy tube introducer.
Percutaneous tracheostomy is a common procedure in Intensive Care Units. There are numerous methods of cannulating the trachea and the technique has evolved over the last 20 years from dilatation with forceps and multiple serial dilators to single tapered dilators. The procedure is safe and compares favourably to surgical tracheostomy [1]. However, the procedure is not without risks and there are many potential complications. Excessive force used during the dilatation of the tracheal stoma and insertion of the tracheostomy tube may contribute to some of these complications. Tracheal ring fractures and posterior wall mucosal damage may lead to tracheal lumen narrowing and stenosis. The success of the procedure is dependent on careful patient selection and operator skill, but the type of tracheostomy set may also have a bearing on the incidence and severity of complications.
The most commonly used set in the UK [2] is the Blue Rhino™ Percutaneous Tracheostomy Introducer Set (Cook Critical Care, Bloomington, IN), which is a modification of the Ciaglia serial dilator technique involving a single step, curved hydrophilic-coated Blue Rhino™ dilator. After dilating the tracheal stoma, the tracheostomy tube is loaded onto an appropriately sized dilator and inserted over the guidewire into the stoma. The Portex Ultraperc™ (Smith Medical, Hythe, Kent, UK) offers a similar set with a single step, curved hydrophilic white dilator but in addition provides a tapered introducer for the tracheostomy tube.
This study aims to compare the two dilator techniques: the Blue Rhino™ and the Ultraperc™.
The study was carried out in two parts, initially on a mannequin and subsequently on a porcine airway model, to collect the following information:
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the subjective ease of dilating the trachea and inserting the tracheostomy tube;
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the time taken and the anterior–posterior compression during dilatation and tube insertion;
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the incidence and extent of posterior tracheal wall damage.
Formal ethical committee approval was not required for this study in our institute as there was no involvement of patients or animal sacrifice.
Method
Study outline
In view of the similarities between the two sets and the relatively low incidence of complications with percutaneous tracheostomies, significant differences in outcome would be difficult to demonstrate in patients. Therefore, the study was carried out on two separate airway models to obtain as much information as possible.
Part 1: Tracheostomies were performed on a Portex training mannequin (TOT100 Tracheostomy Trainer and Case) with a fixed 18 mm internal diameter rubber trachea covered with a removable skin and soft tissue. The skin was changed and a new tracheal stoma was created with each tracheostomy. The time to dilate and insert the tracheostomy tube was measured by the non-operator. The procedure was carried out under rigid bronchoscopic video guidance (Karl Storz-Endoskope: 39301ACT) to allow the anterior–posterior compression to be measured from video footage.
Part 2: Tracheostomies were performed on a porcine airway model (Fresh Tissue Supplies Ltd, Horsham, West Sussex, UK) which consisted of a dissected complete trachea and larynx with surrounding skin. Pig tracheas have been validated previously to replicate human anatomy and size, and accommodate 8 mm internal diameter tracheal tubes [3]. The procedure was again timed. Following successful tracheal cannulation, the trachea was dissected to assess the incidence and extent of tracheal mucosal damage.
Equipment
Size 8 tracheostomy sets and tubes were used, as this is the most frequently used size in adult critically ill patients. The equipment from Cook consisted of the Ciaglia Blue Rhino™ Percutaneous Introducer Set, which was prepacked with a Tracoe Twist Tracheostomy Tube (the tube which is recommended by Cook). The equipment from Portex consisted of the Ultraperc™ Percutaneous Dilation Tracheostomy Set with the Blue Line Ultra Tracheostomy Tube and Introducer. The dimensions of the tracheostomy tubes are shown in Table 1.
| Tracoe Twist Tracheostomy Tube(for the Blue Rhino™) | Portex Blue LineUltra TracheostomyTube | |
|---|---|---|
| Outer diameter; mm | 11.4 | 11.9 |
| Inner diameter; mm | 8.0 | 8.0 |
| Length; mm | 76.0 | 75.5 |
Study protocol
For the first part of the study, two senior anaesthetists experienced in percutaneous tracheostomy insertion, and familiar with both sets, performed 10 tracheostomies each, half with the Blue Rhino™ and half with the Ultraperc™. The technique used was as recommended by the manufacturers with a Seldinger-guidewire technique, and soft tissue and tracheal dilatation with the singled tapered dilator. Data was recorded to measure the difference in performance between the two sets. The data collected included the subjective ease of dilating the trachea (from needle insertion to completion of dilation with the single tapered dilator) and then of inserting the tracheostomy tube. The times taken to dilate the trachea and to insert the tracheostomy tube were measured. The anterior–posterior tracheal diameter compression during dilation and during tracheostomy tube insertion was measured by a blinded assessor from bronchoscopic video footage. The extent of compression was graded from 0–100%.
For the second part of the study, the above protocol was repeated on porcine airway models. The anaesthetists again performed 10 tracheostomies each, five with each set. The tracheostomies on the porcine airway models were not performed under bronchoscopic guidance. The subjective ease and timings were again measured. After each tracheostomy insertion, the porcine trachea was dissected to assess the presence and extent of posterior wall mucosal injury.
Results
In part 1 of the study (mannequin), there was no statistically significant difference in the subjective ease of dilating the trachea or inserting the tracheostomy tube (Table 2). There was also no difference in the time for dilation, but the median time for tracheostomy tube insertion was significantly less with the Ultraperc™: 3 s compared to 7.2 s with the Blue Rhino™, p = 0.0006 (Table 3). The mean percentage anterior–posterior compression was less during dilatation with the Blue Rhino™: 34.8% compared to 51.5% with the Ultraperc™; p = 0014. Overall compression was far greater during tracheostomy tube insertion with the Ultraperc™, causing less compression: 51.5% compared to 76% with the Blue Rhino™, p = 0.0008 (Table 4).
| Tracheostomyset | Easy | Moderate | Difficult | Fisher'sexact p-value | |
|---|---|---|---|---|---|
| Mannequin | |||||
| Subjective ease of dilating trachea | Blue Rhino™ | 9 | 1 | 0 | |
| Ultraperc™ | 8 | 2 | 0 | ||
| Subjective ease of inserting tracheostomy tube | Blue Rhino™ | 3 | 5 | 2 | |
| Ultraperc™ | 8 | 2 | 0 | 0.095 | |
| Porcine airway model | |||||
| Subjective ease of dilating trachea | Blue Rhino™ | 6 | 4 | 0 | |
| Ultraperc™ | 1 | 8 | 1 | 0.057 | |
| Subjective ease of inserting tracheostomy tube | Blue Rhino™ | 1 | 5 | 4 | |
| Ultraperc™ | 9 | 1 | 0 | 0.001 | |
| Blue Rhino™Median (IQR) | Ultraperc™Median (IQR) | Test | p-value | |
|---|---|---|---|---|
| Mannequin | ||||
| Time for dilation; s | 58 (48, 61) | 48 (47, 54) | Log-rank | 0.37 |
| Time for tracheostomy tube insertion; s | 7.2 (4.9, 16.3) | 3 (2.4, 4.1) | Log-rank | 0.0006 |
| Porcine airway model | ||||
| Time for dilation; s | 65 (49, 75) | 56 (51.4, 70) | Log-rank | 0.95 |
| Time for tracheostomy tube insertion; s | 8.5 (7.2, 12.4) | 4.3 (4.0, 4.9) | Log-rank | 0.0005 |
| Blue Rhino™Mean (SD) | Ultraperc™Mean (SD) | Test | p-value | |
|---|---|---|---|---|
| Anterior–posterior compression during dilatation; % | 34.8 (11.8) | 51.5 (16.3) | anova | 0.0014 |
| Anterior–posterior compression during tracheostomy tube insertion; % | 76 (11.7) | 53.9 (9.9) | anova | 0.0008 |
For part 2 of the study (porcine airway model), the Ultraperc™ again showed a significant advantage during tracheostomy tube insertion in terms of subjective ease (p = 0.001; Table 2) and median speed: 4.3 s compared to 8.5 s (p = 0.0005) with the Blue Rhino™ (Table 3). During dilatation, there was no difference in time, but there was a trend towards the Blue Rhino™ being subjectively easier (p = 0.057). The overall incidence of posterior wall damage was high (13/20) with 5/20 having deep lacerations (Table 5). There was no difference between the two sets (p = 0.523).
| Incidence of posteriorwall damage | None | Superficial | Deeplacerations |
|---|---|---|---|
| Blue Rhino™ | 2 | 5 | 3 |
| Ultraperc™ | 5 | 3 | 2 |
- Fisher's exact p = 0.523.
Discussion
The study shows very little difference between the two percutaneous tracheostomy sets during dilatation; however, the Ultraperc™ has a significant advantage over the Blue Rhino™ during insertion of the tracheostomy tube. Dilatation with the Ultraperc™ tracheostomy tube was subjectively easier, and the time taken for insertion and the anterior–posterior compression were less.
The degree of tracheal compression relates to the amount of force required to cannulate the trachea. The force required to insert the tracheostomy tubes may have an impact on the incidence and extent of some of the complications. Peri-operative complications such as tracheal ring fractures [4,5], posterior tracheal wall perforation [6], tracheal abrasions [7] and the creation of false passages [8] have all been described with this technique. The incidence of tracheal narrowing or stenosis is low but not insignificant [7, 8]. Hence, the advantage of less force (as measured by less anterior–posterior compression) required with the Ultraperc™ set may result in fewer such complications.
Both sets allowed tracheal dilatation to be performed quickly with little difference between the two sets. The Ultraperc™, however, had a significant advantage during tracheostomy tube insertion. A shorter insertion time may minimise the transient hypoxia and hypercarbia that occurs during the procedure, but this is unlikely to be of any clinical significance. Raised peak airway pressures have been noted during the procedure [8]. This could be minimised if the procedure were shorter. Insertion time may be of more relevance to those who have reported the use of percutaneous tracheostomies in emergency settings [9, 10], although this is not a universally accepted indication for percutaneous tracheostomy and is not recommended by the authors or the manufacturers of the sets.
The tracheostomy tubes used in the study were both size 8 (8 mm internal diameter). It is notable that the external diameter of the Trachoe tube (for the Blue Rhino™ set) is less than the Portex Blue Line Ultra (for the Ultraperc™ set). However, dilatation with the Ultraperc™ set was subjectively easier, required less force, and the insertion time during tracheostomy tube insertion was shorter. The Ultraperc™ set contains a Portex Blue Line Ultra tracheostomy tube and a tracheostomy tube introducer (Fig. 1), which allows a smooth step-free passage of the tracheostomy tube through the dilated stoma. The Blue Rhino™ set, in contrast, provides an introducing dilator for the Trachoe Twist Tube (Fig. 2), which has a small step between the dilator and the tracheostomy tube. This may account for the greater force and time required to pass the tracheostomy tube through the stoma with the Blue Rhino™.
The Portex Ultraperc™ set with tracheostomy tube and introducer.
The Trachoe Twist tracheostomy tube and the Blue Rhino™ introducing dilator set.
Difficulties with the single dilator Blue Rhino™ technique have been reported in the past, particularly when used in conjunction with the Shiley tracheostomy tubes [11]. Methods to overcome this problem by using alternative tracheostomy tubes have also been described [12, 13]. With the resulting changes, the Portex Ultraperc™ Tracheostomy set appears to be more advantageous in terms of speed and force required to insert the tracheostomy tube.
The Blue Rhino™ caused less anterior–posterior compression during dilatation in the mannequin and dilatation was subjectively easier in the porcine airway model. However, since most of the tracheal compression and difficulty occurs during tracheostomy tube insertion, this subtle advantage during dilatation is not clinically significant.
Clinical studies with tracheostomies performed under bronchoscopic guidance have shown tracheal lumen damage to be as low as 2–4%[14]. The overall incidence of posterior wall damage from the dissected porcine airway model was high (13/20), of which eight were less than 1 mm superficial needle damage and only five were more significantly larger lacerations. Reasons for this may be:
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that the tracheostomies were performed on the porcine airway model without bronchoscopic guidance [15];
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the in vitro pig tracheal lumens lacked the supporting structures and rigidity that one would expect in live human patients.
There was no significant difference between the two sets regarding the incidence and extent of posterior wall damage or wire kinking during insertion.
To reproduce the above differences between the two sets in a clinical study would be difficult. Large patient numbers would be required as the complication rate from percutaneous tracheostomy is so low. Nevertheless, this study does provide useful information which could potentially reduce some of the difficulties associated with percutaneous tracheostomies.
In conclusion, the Ultraperc™ set is subjectively easier, quicker and causes less anterior–posterior tracheal compression during tracheostomy tube insertion compared to the Blue Rhino™ set in both mannequin and porcine airway models. This advantage may be due to the presence of the tracheostomy tube introducer.
Acknowledgements
We thank Caoimhe O'Sullivan, Medical Statistics Unit, UCLH, for her advice and help with statistical analysis. There was no external source of funding and we are grateful to the manufacturers of the tracheostomy sets for providing the equipment free of charge.
