© Springer International Publishing Switzerland 2016
Giuseppe Servillo and Paolo Pelosi (eds.)Percutaneous Tracheostomy in Critically Ill Patients10.1007/978-3-319-22300-1_99. Choice of the Appropriate Tracheostomy Technique
(1)
Department of Anesthesia and Intensive Care, IRCCS San Raffaele Scientific Institute and Vita-Salute San, Raffaele University, Via Olgettina 60, Milan, 20132, Italy
Abstract
Only 16 randomised controlled trials (RCTs) compared the different PDTs in mixed low-risk population: the meta-analyses evaluating their results showed that single-step dilation technique (SSDT) and Griggs dilating forceps technique (GDFT) are superior in terms of procedural efficacy and safety; moreover, SSDT appeared the best one for short-term complication rate, while no difference was present for midterm and long-term complications. Similar findings come from nonrandomised studies.
Few, low-quality data are available for high-risk groups. SSDT is the only technique evaluated in obese patients: it appeared safe, but the risk of complication could be higher compared to non-obese patients. In patients at higher risk of bleeding, SSDT could be the safest choice, while GDFT seems associated with a higher incidence of bleedings. In hypoxaemic patients, SSDT could be the technique of choice due to its easiness, but a careful ventilator setting is needed as SSDT might increase the incidence of pneumothorax. In neurosurgical patients, GDFT is the best evaluated technique: intracranial pressure can increase during the procedure, but cerebral perfusion pressure seems preserved with GDFT.
Finally, long-term outcomes are difficult to evaluate, as few survivors are commonly available at follow-up. Tracheal stenosis incidence seems not different between SSDT and GDFT; however, SSDT causes more tracheal ring fracture, an injury suspected to predispose to stenosis. Hoarseness and disturbing symptoms (but not vocal cord paralysis) are more common with SSDT, while cosmetic problems seem to be minimised using SSDT.
9.1 Introduction
A recent meta-analysis [1] demonstrated that percutaneous dilatational tracheostomy (PDT) is superior to surgical tracheostomy performed in the operating theatre in terms of reduction in wound infection and suggested that it might reduce clinically relevant bleeding and mortality. Even though at least six different techniques/devices are commercially available and each one has a different risk profile and can probably offer different advantages, PDT is often considered as a unique entity. Few randomised controlled trials (RCTs) comparing the various PDT techniques are available, and most of these comparisons were performed in low-risk patients. Nonetheless, the results of these comparisons can be helpful when choosing the best technique for a specific patient. Observational prospective and retrospective studies offer further information on this issue, in particular on the use of PDT in high-risk patients. The aim of this chapter is to summarise the best evidence on safety and efficacy of the different PDT techniques.
9.2 Results from RCTs
To the best of our knowledge, so far only 16 RCTs comparing at least two PDT techniques have been published in peer-reviewed, indexed journals [2–17]. Three meta-analyses recently compared the commercially available PDT techniques [18–20].
Data are limited in most cases, with five RCTs comparing single-step dilation technique (SSDT) and Griggs dilating forceps technique (GDFT), four RCTs comparing GDFT with multiple steps technique (MST) and with all other comparisons based on two or less studies. No technique was compared to all the others, and, as a consequence, in many cases, we must rely on indirect comparisons.
All RCTs took place in intensive care units (ICU), but inclusion/exclusion criteria were heterogeneous. All RCTs but one [17] were performed in a mixed population, generally excluding high-risk conditions like coagulopathy and anatomical distortion.
The two meta-analyses that included and compared all six existing PDT techniques [18, 20] showed that three techniques (GDFT, SSDT, MST) are largely equivalent, while the other three (rotational technique, RT; translaryngeal technique, TL; and pneumatic dilation technique, PT) are more dangerous and/or less effective. Among the three best techniques, SSDT resulted slightly superior to GDFT causing less mild complications. It should be underlined that the three “worst” techniques were evaluated together in only six RCTs, that in most cases the ICU staff was at the beginning of the learning curve for these relatively “new” techniques, while it was already expert in older techniques and that only short-term outcomes were analysed (failure rate, intraoperative mild and severe complications).
Even though the findings of the RCTs showed equivalence between MST and SSDT, SSDT has now commercially replaced its predecessor MST, and the best PDT technique is therefore to be identified between GDFT and SSDT. This was the aim of a recent meta-analysis that also attempted to compare midterm and long-term outcomes [19]. The pooled comparison of the five available RCTs showed that the incidence of intraoperative technical problems (the sum of difficult cannula insertion and failures) was statistically significantly higher with GDFT (15.5 % with GDFT vs. 4.9 % with SSDT, OR 2.6, CI 1.14–6.00, P for effect = 0.02, P for heterogeneity = 0.4). Interestingly, all the five GDFT failures were completed crossing to SSDT technique, and the only SSDT failure was completed using a surgical approach. Mild and severe bleeding was also more common with GDFT (19.3 % with GDFT vs. 7.6 % with SSDT, OR = 2.31, CI 1.15–4.61, P for effect = 0.018, P for heterogeneity = 0.5). No other statistically significant differences were observed for intraoperative complications, even if a non-significant trend was present for stoma overdilation (7 cases with GDFT vs. 1 with SSDT, OR = 1.89, CI 0.39–9.32, P for effect = 0.4, P for heterogeneity = 0.6) and tracheal ring fracture (1 case with GDFT vs. 12 with SSDT, OR = 0.33, CI 0.08–1.37, P for effect = 0.13, P for heterogeneity = 0.7). A non-significant trend (p = 0.3 in both cases) was reported for midterm complications (bleeding episodes while cannulated were 4 in GDFT group vs. 9 in SSDT group OR = 0.58, CI 0.20–1.65) and for late disturbing symptoms after decannulation (27 in GDFT, 39 in SSDT, OR = 0.7, CI 0.37–1.33).
We underline again that such comparison was based on a limited number of cases (less than 400 patients randomised) and that considering the low incidence of most complications, all the RCTs were underpowered to identify differences. This is particularly true for midterm and long-term outcomes, as many patients die while cannulated or shortly after decannulation before hospital discharge, further reducing the power of the analyses. However, these data constitute the best evidence available so far. Unfortunately, no data on cost-effectiveness were reported.
9.3 Comparisons in Non-RCT Studies
Few studies compared the PDT techniques with a retrospective or prospective (but not randomised) design [21–23]. Three [21–23] out of six studies came from the same German centre, in Frankfurt, in which also some of the RCTs took place.
Three studies compared TL (or “Fantoni”) to GDFT or MST. When compared to GDFT, TL required more time (9.2 vs. 4.8 min) and no other significant differences and with two (4 %) major complications in each group [21]. In the two studies comparing TL and MST [22, 23], the only reported significant difference was a better post-procedural PaO2/FiO2 ratio in the TL group with similar procedure time and technical problems with guide wire advancement observed in one-third of TL cases.
One nonrandomised study compared RT (or “PercuTwist”) and SSDT [24]. RT required a longer procedure time (12 vs. 8 min), and 3/24 (12.5 %) patients in the RT group vs. 2/116 (1.7 %) in the SSDT group presented an erosion of the posterior tracheal wall; all differences were not statistically significant.
One study [25] compared GDFT and MST in neurosurgical patients. No statistically significant difference was reported with a trend towards more overall complications and longer procedural time in the MST group.
Finally, one relatively large nonrandomised prospective study compared GDFT and SSDT [26], including midterm and long-term outcomes. Difficult stoma dilation (0 % vs. 13.5 %) and total number of intraoperative minor complications were more common in the SSDT group, while all the three failed procedures were in the GDFT group. The only significant differences at the long-term follow-up were a higher incidence of voice changes and hoarseness in the SSDT group (22 % vs. 8.5 %) and a higher incidence of cosmetic problems with GDFT (9.4 % vs. 2 %).
In conclusion, results of nonrandomised studies confirm that PDT is generally a safe procedure and that GDFT and SSDT are slightly superior to the other techniques, even if also non-RCTs appeared underpowered to reliably detect differences in complications.
9.4 Current Practice
Two national surveys assessed current practice of tracheostomy. Kluge et al. [27] found that SSDT was the preferred technique in Germany (69 % of respondents). In a recent survey in Italy, Vargas reported that SSDT was the most commonly used PDT technique (33 %) [28]. Finally, SSDT was recommended in the guidelines on tracheotomy published by the Belgian Association of Pneumology and the Belgian Association of Cardiothoracic Surgery [29]. SSDT was the chosen technique in a multidisciplinary PDT programme at the Johns Hopkins Hospital [30].
9.5 Choosing the Best Technique for High-Risk Subgroups
Even if PDT was traditionally contraindicated in obese patients, in those with elevated risk of bleeding and with hypoxic respiratory failure, in recent years these conditions have became relative rather than absolute contraindications (along with a growing number of studies showing a higher than expected safety of PDT in these patients) [31].
Since no RCT comparing two PDT techniques was performed in high-risk patients and no retrospective or observational study aimed at comparing the safety and effectiveness of different PDT techniques in these subgroups exists, the choice of PDT is based on a low level of evidence, and only a prudential suggestion, with the strength not higher than that of an expert opinion, can be formulated.
9.5.1 Obesity
Obesity is a growing problem in most western countries and is associated with a high incidence of complications during surgical or percutaneous tracheostomy [32, 33]. Obesity is also the main risk factor for PDT-related deaths associated with airway complications [34]. More recently the incidence of major complications during PDT in this challenging situation was reported to range from 0 to 12 % [35].
SSDT is the only technique that has been specifically evaluated in obese patients. Romero et al. [36] in a prospective study found no difference in complication rate between obese and non-obese patients; nevertheless, a trend towards a higher incidence of postoperative complications (tracheostomy tube displacement) was present in the obese group. Heyrosa et al. [37], in a retrospective study in 89 obese patients, reported a complications rate of 5.6 % in the SSDT group, identical to the incidence reported in the surgical tracheostomy group. The five patients with complications in the SSDT group (loss of the airway, bleeding, malpositioning or difficult insertion of the cannula) required conversion to surgery in four cases. McCague et al. [38] did not find significant differences between obese and non-obese patients while using the SSDT in 426 cases. The same findings had been reported by Rosseland in 1000 PDTs [39]. Finally, Dennis et al. [35] in the largest retrospective study on more than 3000 PDT analysed almost 1000 overweight-obese patients reporting a complication rate of 1 % and no conversion to surgery. The complication rate in the overall population was 0.38 %.
SSDT proved safe and successful in obese patients in a limited number of nonrandomised studies. In the absence of comparative studies, we don’t know if other techniques are better or worse, and actually some authors preferred TL [40]. However, in comparative RCTs in unselected patients, SSDT demonstrated to be technically the easier method [18, 19]. On the basis of available data, choosing SSDT in obese patients seems reasonable. An expert team adequately equipped is mandatory. Ultrasound evaluation and guidance could also be of help in limiting risks [41].
9.5.2 Patients at Higher Risk of Bleeding
In this subgroup, we include patients affected by coagulopathy or thrombocytopenia and patients under treatment with anticoagulant or antiplatelet drugs. The issue is of relevance, as post-procedural haemorrhage is the main cause of death PDT related as recently reported by Simon et al. [34]: coagulopathy was found in 5 out of 27 patients who died.
Despite being traditionally considered a relative contraindication, coagulopathy did not result to increase the risk of bleeding in a retrospective analysis of 483 PDTs [42]. In line with this finding, Veelo et al. reported that the correction of subclinical disorders (abnormal platelet count or prothrombin time or single antiplatelet therapy) did not further reduce the already low incidence of bleeding [43]. In another study, abnormal partial thromboplastin time or low platelet count was associated with chronic bleeding [44].
Again, as observed in obese patients, we lack prospective or retrospective studies comparing different PDT techniques, and we must rely on case series describing only one technique in this high-risk population.
Barton et al. found no association between coagulation values or prophylactic anticoagulation or antiplatelet therapy and risk of bleeding in 352 MST, while platelet count was significantly lower in patients experiencing bleeding events [45]; however, all episodes of bleeding were of mild severity.
Using GDFT in patients with severe thrombocytopenia treated with pre-operative platelets transfusion, Kluge observed a 5 % major bleeding episodes requiring sutures in patients who had an elevated APTT due to heparin infusion [46]. In a prospective study including patients at higher risk of bleeding or obese, Rosseland found that SSDT was associated with a low risk of bleeding; increased INR was the most important risk factor for bleeding, followed by low platelet count [39]. In a small prospective study including 32 patients with coagulopathy or thrombocytopenia, after correction with fresh frozen plasma (FFP) and/or platelet transfusion, only one major bleeding (requiring surgery) and three minor bleedings were reported [47]. Auzinger et al. evaluated 60 patients with severe liver disease, 25 of whom had secondary coagulopathy refractory to FFP and platelets transfusion: SSDT was used in 43 cases and MST in 18. Only one patient in the refractory group suffered from major bleeding requiring further transfusion, and no significant difference was present among refractory and not refractory coagulopathy groups [48]. SSDT was also applied uneventfully in two patients under ongoing double antiplatelet therapy [49]. Finally, SSDT was used in 118 patients on extracorporeal lung support [50]; preventive treatment with FFP or platelets transfusion was administered in a minority of cases, while heparin infusion was stopped 1 h before the procedure. Two major bleedings (1.7 %; one requiring surgery) and 37 minor bleedings were observed; no clotting complication of the extracorporeal devices happened.