- Email: [email protected]
Learning curve for real-time ultrasound-guided percutaneous tracheostomy
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ACCPM-207; No. of Pages 5 Anaesth Crit Care Pain Med xxx (2016) xxx–xxx
Original Article
Learning curve for real-time ultrasound-guided percutaneous tracheostomy Sandra Petiot a, Pierre-Gre´goire Guinot a,*, Momar Diouf b, Elie Zogheib a, Herve´ Dupont a a b
Department of anaesthesiology and critical care medicine, Amiens university hospital, place Victor-Pauchet, 80054 Amiens, France Centre de recherche clinique, CHU d’Amiens, 80054 Amiens, France
A R T I C L E I N F O
A B S T R A C T
Article history: Available online xxx
Objectives: The objective of this study was to demonstrate and quantify the ultrasound-guided percutaneous tracheostomy (UPDT) learning curve in a single team since the first UPDT. Study design and patients: This was a cohort of all consecutive patients undergoing UPDT in the Amiens teaching hospital surgical intensive care unit between 2010 and 2014. Methods: The learning process was evaluated according to three aspects: duration of the various steps involved in UPDT, incidence of consecutive complications, and procedure difficulty. Results: During the study period, 85 consecutive patients underwent UPDT with no deaths. The mean total procedure time was 22 (10) minutes (range: 7 to 60). Analysis of mean cumulative UPDT procedure times showed that total UPDT time decreased to a stable duration of 25 minutes after 54 procedures. Complications were observed in 24 (28%) of the 85 patients. The overall complication rate decreased to below a stable percentage of 30% after 70 procedures. The minor complication rate decreased below 25% after 64 procedures. The moderate complication rate decreased to below a stable percentage of 10% after 10 procedures. The major complication rate decreased to below a stable percentage of 5% after 20 procedures. Most complications were observed in the first 50 patients (25 [50%] versus 6 [13%], P < 0.05). Conclusions: Our study demonstrated that UPDT is associated with a fairly long learning curve. At least 50 procedures are necessary to perform UPDT with an acceptable complication rate and procedure time. ß 2016 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Keywords: Ultrasound Percutaneous tracheostomy Learning curve
1. Introduction Since the original description of percutaneous dilatational tracheostomy (PDT) by Ciaglia in 1985, this technique has become increasingly popular [1] and is now commonly used at the bedside in critical care medicine. Since ultrasound (US) has become a widely used tool in the critical care unit, several studies have recently assessed the feasibility of real-time ultrasound-guided tracheostomy [2–4]. Numerous interventional tasks have been reported to be improved by US guidance in the literature, such as real-time US-guided central venous catheter placement [5]. Several studies have demonstrated the safety of real-time US-guided percutaneous tracheostomy (UPDT), even in obese patients [2,3] and have reported low complication rates with no life-threatening complications based on improved visualization of neck anatomy before and during the procedure [2]. However, UPDT is a new * Corresponding author. E-mail address: [email protected] (P.-G. Guinot).
technique, used by only a few teams and no data are available about the UPDT learning curve. The objective of this prospective study was to demonstrate and quantify the UPDT learning curve in a single team. 2. Methods This study included all consecutive patients undergoing PDT in the Amiens teaching hospital surgical intensive care unit between 2010 and 2014. The study was approved by the local ethics committee (Comite´ de protection des personnes Nord Ouest, CHU d’Amiens,1 number 2010/29 and 2014/73), and all patients were provided with written information and gave their informed consent. Exclusion criteria were age under 18 years, clotting disorder (international normalized ratio > 2, activated partial thromboplastin time [APTT] > 1.5, and platelet 1 IRB contact information: Comite´ de protection des personnes, Nord-Ouest II CHU, place V. Pauchet, 80054 Amiens cedex 1.
http://dx.doi.org/10.1016/j.accpm.2016.07.005 2352-5568/ß 2016 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Petiot S, et al. Learning curve for real-time ultrasound-guided percutaneous tracheostomy. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.07.005
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ACCPM-207; No. of Pages 5 S. Petiot et al. / Anaesth Crit Care Pain Med xxx (2016) xxx–xxx
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count < 50 109/L), puncture site infection and emergency tracheostomy. 2.1. Percutaneous tracheostomy technique Percutaneous tracheostomy was performed using the singlestep, progressive Ciaglia Blue Rhino technique, as previously described [6,7]. The PCT set consisted of a puncture needle, a guide wire, a small dilator, a curved dilator with a hydrophilic coating and a tracheostomy tube (Tracoe1 expert dilatation set from Pouret Medical, Clichy, France). 2.2. Critical care team The same team composed of two physicians performed each UPDT procedure. Both physicians had more than 5 years of experience with point-of-care US. They also performed other ultrasound-guided invasive procedures such as central venous catheter placement and/or nerve blocks. Both had performed more than 50 PDT procedures according to the modified Ciaglia technique. However, they had no prior experience with the UPDT technique. 2.3. Ultrasound guidance The UPDT procedure was performed at the bedside under deep sedation, analgesia and muscle relaxation using the same US machine and probe (Envisor1 point-of-care system or Cx 50 CompactXtrem with a 12- to 3-MHz linear array probe [Philips Medical Systems, Best, The Netherlands]). The patient was ventilated under controlled ventilation with 100% FIO2. The UPDT procedure required three persons: one person to manage the airway, and two operators performing UPDT. The procedure was always performed according to the same protocol. First, the two operators, in sterile gowns, performed sterile draping of the neck, skin disinfection and sterile draping of the US probe. Point-of-care US was performed at the patient’s bedside. An US examination of the neck area was performed, using transverse and longitudinal views [2]. Transverse sections identified arteries, veins, thyroid, trachea, endotracheal tube and measured skin thickness over the anterior tracheal wall. The longitudinal view identified the various tracheal rings and guided the level of puncture. After this step, the physician standing at the patient’s head withdrew the endotracheal tube balloon to near the vocal cords under direct laryngoscopic guidance. The modified Ciaglia technique under ultrasound guidance was then initiated using a modified Blue Rhino dilator Tracoe1 (Pouret medical, Clichy, France) [1]. A puncture needle with a saline-filled syringe was introduced perpendicularly to the skin and advanced until the needle was seen to pass the anterior tracheal wall during inspiration. The needle was then angled caudally to prevent retrograde passage of
the guide wire. The needle was visualized in ‘‘out-of-plane’’ mode (i.e., the needle path was determined by the presence of a distinct acoustic shadow ahead of the needle) on a transverse section of the neck. The guide wire was introduced, the needle was removed, and a small horizontal incision was made at the point of puncture. The guide wire was visualized as a hyperechoic signal on transverse and longitudinal sections. The small dilator was then used to create the initial stoma, followed by the single-stage curve dilator over the guide wire. The tracheostomy tube fitted over an appropriate loading tube was passed through the stoma. US guidance allowed the operator to check the correct positioning of the puncture site and guide wire before dilatation of the trachea followed by tracheostomy tube placement. 2.4. Data collection Demographic and clinical data were collected, including gender, age (years), height (metres), weight (kilograms), body mass index (BMI), Simplified acute physiology score II (SAPS II), admission diagnosis, duration of mechanical ventilation prior to PCT (days), and indication for tracheostomy. An anatomical criterion of difficult tracheostomy was noted: presence of a short neck. The following US data were also recorded: level of the thyroid, presence of tracheal deviation, aberrant vessels, puncture site, subcutaneous tissue thickness (centimetres) defined by the distance between the skin and the anterior tracheal wall measured perpendicularly to the skin at the puncture site, tracheal diameter (centimetres). The difficulty of the US-guided technique was scored on a simple numerical scale; 1: easy; 2: minor difficulties in identifying anatomical structures and tracheostomy tube placement; 3: moderate difficulties in identifying anatomical structures; 4: very difficult; and 5: impossible [2]. 2.5. Definition of complications Complications occurring between the beginning of UPDT and decannulation were recorded. Bronchoscopy was performed before decannulation in order to detect any long-term complications. Complications were classified in two ways: according to their severity as minor (irrelevant for the patient), moderate (potentially harmful) and major complications (harmful and requiring immediate treatment) (Table 1); according to their chronology as technical, intra-procedural and post-procedural [2]. 2.6. Construction of the learning curve The learning curve was based on three aspects of UPDT. First, we evaluated the duration of the various steps of UPDT: installation
Table 1 Classification of complications. SpO2, oxygen saturation as measured by pulse oximetry. Minor
Moderate
Major
Bleeding not requiring compression or administration of packed red blood cells Hypoxaemia (SpO2 of less than 90%) and/or hypotension (systolic blood pressure less than 100 mmHg) for less than 5 minutes Difficult puncture or multiple punctures (more than three) Puncture of the tracheal tube cuff Peristomal infection not requiring antibiotic therapy
Bleeding requiring compression without blood transfusion Posterior tracheal wall injury not requiring surgical repair
Bleeding requiring administration of packed red blood cells
Atelectasis Tracheal ring fracture
Subglottic stenosis Granuloma Malposition of the tracheostomy tube (pretracheal or paratracheal insertion)
Oesophageal injury
Posterior tracheal wall injury requiring surgical repair Pneumothorax Peristomal infection requiring local care or antibiotic therapy or both Loss of airway Surgical conversion Cardiac arrest Death
Please cite this article in press as: Petiot S, et al. Learning curve for real-time ultrasound-guided percutaneous tracheostomy. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.07.005
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time (minutes), duration of tracheostomy defined by the time (minutes) between puncture of the trachea and ventilation of the patient. Secondly, we assessed the incidence of consecutive complications (Table 1). The ‘‘acceptable rate’’ was defined on the basis of the results of various studies evaluating percutaneous tracheostomy [8–10]. The incidence of each category of complication was defined (minor: 30%, moderate: 10%, major: 5%) [8– 14]. Thirdly, we evaluated the time-course of the difficulty of performing UPDT based on a scale. 2.7. Statistical analysis Variable distributions were assessed using the D’AgostinoPearson test. Data were expressed as means (SD), medians (25– 75 percentiles) or numbers (percentage). To construct learning curves, data were arranged in chronological order. The cumulative proportion (for qualitative variables) and the cumulative mean (for quantitative variables) were computed after each new tracheotomy procedure. The learning curve was plotted with the cumulative number of tracheotomies on the X-axis and the cumulative proportion or cumulative mean on the Y-axis, as appropriate. The horizontal line defined by the target value of cumulative proportion or cumulative mean was added to the plot. A simpler analysis of complication rates, comparing the first 50 patients and subsequent patients, was also performed. Complication rates were analysed by comparing sequential cohorts using Fisher’s exact tests. All statistical analyses were performed with open-source R.3.1.0 software. 3. Results During the study period, 85 consecutive patients with a mean age of 57 [8] years underwent UPDT. All UPDTs were performed successfully with no deaths in this series. The median level of puncture was situated between the 2nd and 3rd tracheal rings. Patient characteristics are provided in Table 2. In this series of 85 patients, 43 (51%) were medical intensive patients (respiratory failure secondary to chronic obstructive pulmonary disease, acute respiratory syndrome, pneumonia, stroke, seizures, acute heart failure, cardiac arrest, etc.), and 42 (49%) were surgical intensive patients (cardiac, vascular or digestive surgery, or severe trauma). 3.1. Time of procedure The mean total procedure time was 22 [12] minutes (range: 7 to 60 minutes). The mean duration of sterile draping and US
Table 2 Patient characteristics. Male/female Age (years) Weight (kg) Height (m) BMI SAPS II Mechanical ventilation before UPDT (days) Anatomical characteristics Short neck Thyroid goitre Neck trauma Ultrasound characteristics Tracheal diameter (cm) Subcutaneous tissue thickness (cm) Aberrant vessels
61/24 57 (6) 87 (23) 1.7 (0.1) 30.5 (8) 44 (14) 24 (9) 39 (46%) 11 (13%) 2 (2%) 2.04 (0.47) 1.15 (0.52) 36 (42%)
Values are expressed as means (SD) or numbers (percentage). BMI: body mass index; SAPS II: simplified acute physiology score II; UPDT: ultrasound-guided percutaneous dilatational tracheostomy; COPD: chronic obstructive pulmonary disease.
Fig. 1. Cumulative mean total time according to the number of UPDTs. The line represents stabilization of the cumulative mean total time.
landmarking before incision was 11 [8] minutes. The mean time from incision to fixation was 10 [8] minutes. Analysis of the cumulative mean total UPDT time showed that the total UPDT time decreased to a stable duration of 25 minutes after 54 procedures (Fig. 1). The same analysis of cumulative mean UPDT time from incision to fixation showed that the mean time decreased to below a stable duration of 11 minutes after 68 procedures. 3.2. Complications Complications were observed in 24 (28%) of the 85 patients. The cumulative number of complications was 31, with 24 minor complications, 6 intermediate complications and one major complication. Five patients presented more than one complication (4 patients with two complications and 1 patient with five complications). Minor complications were tracheal ring fracture (n = 2), puncture of the tracheal tube cuff (n = 8), minor bleeding (n = 7), desaturation or hypotension lasting less than 5 minutes (n = 5) and multiple punctures (n = 2). Moderate complications were granulomas (n = 3) and bleeding requiring compression (n = 3). The major complication consisted of a peristomal infection, requiring antibiotic therapy. Most complications were observed in the first 50 patients (25 [50%] versus 6 [13%] complications, P < 0.05). The overall complication rate decreased to below a stable percentage of 30% after 70 procedures. The minor complication rate decreased to below 25% after 64 UPDTs (Fig. 2A). The moderate complication rate decreased to below a stable percentage of 10% after 10 UPDTs (Fig. 2B). The major complication rate decreased to below a stable percentage of 5% after 20 procedures (Fig. 2C). 3.3. Procedure difficulty The mean score was 2 (0.8) with 39 (46%) procedures scored as 1, 28 (33%) scored as 2, 17 (20%) scored as 3, and 1 (1%) scored as 4, with no failed procedures. UPDT difficulty stabilized between a score of one and two after 25 procedures. 4. Discussion This is the first study to evaluate the UPDT learning curve. Based on our cohort, at least 50 UPDTs are necessary to achieve an acceptable complication rate and procedure time.
Please cite this article in press as: Petiot S, et al. Learning curve for real-time ultrasound-guided percutaneous tracheostomy. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.07.005
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Fig. 2. Cumulative incidence of complications according to the number of UPDTs: the line represents the stable 30% complication rate. The same analysis was performed for the minor complication rate with a stable rate of 25% (graph A), the moderate complication rate with a stable rate of 10% (graph B) and the major complication rate with a stable rate of 5% (graph C). UPDT: ultrasound-guided percutaneous dilatational tracheostomy.
Determination of the learning curve of a procedure must take into account various aspects of the procedure. We therefore based our analysis on 3 different criteria: procedure time, complication rates and procedure difficulty. This approach was used by Nguyen et al. to determine the learning curve for ultrasound-guided jugular central venous catheter placement [15]. The number of procedures required for catheter placement mastery was smaller than for UPDT (at least 20), but UPDT requires more training compared to a simple ultrasound-guided puncture. One finding of this study was that the real-time ultrasoundguided procedure was not as simple as expected. A rather long learning phase was required to decrease the complication rate and procedure time. In order to identify neck structures, the operator must choose the level of puncture and learn US anatomy of the neck as described by Singh et al. [16]. For example, the presence of air in the trachea, which is a poor US conductor, makes it difficult to identify the needle tip or the extremity of the endotracheal tube. At the beginning of the series, this poor visualization was responsible for tracheal cuff punctures because of incomplete US-guided tube removal. The incidence of tracheal cuff puncture subsequently decreased. Several other procedures are performed under US for UPDT: needle puncture, guide and dilator introduction in 2 dimensions (longitudinal and transverse). Nevertheless, our results are similar to those reported by Massick et al. [17], who found similar rates of the same complications but with not exactly the same list of events. Massick’s study is also the only study to assess the learning curve for percutaneous dilatational tracheostomy without ultrasound and bronchoscopic guidance. They based their learning curve exclusively on a decreasing complication rate and found that 20 procedures were necessary. A greater number of procedures was required to decrease the overall complication rate in our study, but differences in the definition and classification of complications make it difficult to compare results [2,17]. The target percentages were chosen after analysis of the literature on the complications of percutaneous dilatational tracheostomy [8–12], based on a very detailed inventory of events, as described by Byhahn to optimally assess the complications associated with PCT [14]. Even the minor complication rate may appear to be high; most of these complications were recorded in order to allow comparison with other studies. The clinical significance of bleeding less than 5 mL not requiring compression, or tracheal cuff puncture can be questioned as they have no consequences for the patient. The minor complication rate was therefore inevitably high and difficult to decrease. A previous study demonstrated that the learning curves associated with various manual skills in anaesthesiology varied greatly between procedures: orotracheal intubation required 57 procedures, while epidural anaesthesia required up to 90 procedures [18]. Learning a procedure is a complex process
dependent on many factors such as the learning environment or inter-individual variations. We chose to describe the UPDT learning curve performed by a single team in order to limit these biases. The definition of a procedure learning curve is very important in order to adapt training. A large number of procedures are required in order to master the ultrasound guidance of percutaneous tracheostomy, but it is difficult to perform all of these procedures over a short period of time because tracheostomies are not performed on a daily basis in the ICU. A recent French survey suggested that an intensivist performed between 2 and 4 tracheostomies per month [6], suggesting that the development of simulation training would be the best non-invasive way to ensure the proper acquirement of a new skill, as demonstrated for emergency cricothyrotomy [7]. Moreover, simulation complies with the precept: ‘‘never the first time on the patient’’. Percutaneous tracheostomy training has been previously developed on a pig model, but this model is unsuitable for repeated procedures [19]. A UPDT phantom therefore needs to be developed to allow simulation training on a model and technique sharing. The study has a number of limitations. First, the learning curve may apply only to the study team and the percutaneous dilatational technique. It could vary among ICU teams, depending on their experience with ultrasound and the percutaneous dilatational technique. A larger study must be conducted to confirm these results. Second, to be reproducible, studies must use a standardized classification of complications. One difficulty concerns the definition of complications. An abundant literature has been published on PCT and complications [2,8–14]. However, most of larger studies are retrospective with several definitions of complications. Consensual definitions must be used in order to allow comparison between studies. To facilitate such comparison, we chose to use previously published definitions [2]. Thirdly, the number of procedures required to master UPDT may appear to be high, but it must be remembered that this study concerned a new procedure with no previous description of limitations. The learning curve only concerned the development of the real-time ultrasound-guided technique: the team had no experience with UPDT before the beginning of the study but a good prior experience of the Ciaglia technique without ultrasound and the use of ultrasound guidance (for catheter placement or nerve blocks). Our results reflect the difficulty of performing a new procedure at the bedside. As indicated above, tracheal cuff puncture was frequent at the beginning of our experience due to the difficulty of identifying the tracheal cuff by ultrasound [2]. 5. Conclusion In conclusion, our study demonstrated the existence of a fairly long UPDT learning curve. At least 50 UPDT procedures are
Please cite this article in press as: Petiot S, et al. Learning curve for real-time ultrasound-guided percutaneous tracheostomy. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.07.005
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necessary to achieve an acceptable complication rate and procedure time. Finally, a UPDT simulation-training programme should be developed. Funding No external funding received. Disclosure of interest The authors declare that they have no competing interest. Acknowledgements None. References [1] Ciaglia P, Firsching R, Syniec C. Elective percutaneous dilatational tracheostomy. A new simple bedside procedure; preliminary report. Chest 1985;87: 715–9. [2] Guinot PG, Zogheib E, Petiot S, Marienne JP, Guerin AM, Monet P, et al. Ultrasound-guided percutaneous tracheostomy in critically ill obese patients. Crit Care 2012;16:R40. [3] Rajajee V, Fletcher JJ, Rochlen LR, Jacobs TL. Real-time ultrasound-guided percutaneous dilatational tracheostomy: a feasibility study. Crit Care 2011; 15:R67. [4] Rudas M, Seppelt I. Safety and efficacy of ultrasonography before and during percutaneous dilatational tracheostomy in adult patients: a systematic review. Crit Care Resusc 2011;14:297–301. [5] Karakitsos D, Labropoulos N, De Groot E, et al. Real-time ultrasound-guided catheterisation of the internal jugular vein: a prospective comparison with the landmark technique in critical care patients. Crit Care 2006;10:R162.
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[6] Blondonnet R, Chabanne R, Godet T, et al. Tracheostomy in French ICUs and patient outcome: National opinion survey. Ann Fr Anesth Reanim 2014; 33:227–323. [7] Hubert V, Duwat A, Deransy R, Mahjoub Y, Dupont H. Effect of simulation training on compliance with difficult airway management algorithms, technical ability, and skills retention for emergency cricothyrotomy. Anesthesiology 2014;120:999–1008. [8] Gobatto AL, Besen BA, Tierno PF, et al. Comparison between ultrasound- and bronchoscopy-guided percutaneous dilational tracheostomy in critically-ill patients: a retrospective cohort study. J Crit Care 2015;30:e13–7. [9] Cianchi G, Zagli G, Bonizzoli M. Comparison between single-step and balloon dilatational tracheostomy in intensive care unit: a single-centre, randomized controlled study. Br J Anaesth 2010;6:728–32. [10] Fikkers BG, Staatsen M, van den Hoogen FJ, van der Hoeven JG. Early and late outcomes after single step dilatational tracheostomy versus the guide wire dilating forceps technique: a prospective randomized clinical trial. Intensive Care Med 2011;37:1103–9. [11] Hatfield A, Bodenham A. Portable ultrasonic scanning of the anterior neck before percutaneous dilatational tracheostomy. Anaesthesia 1999;54:660–3. [12] Sustic´ A, Kovac D, Zgaljardic´ Z, Zupan Z, Krstulovic´. Ultrasound-guided percutaneous dilatational tracheostomy: a safe method to avoid cranial misplacement of the tracheostomy tube. Intensive Care Med 2000;26:1379–81. [13] Simon M, Metschke M, Braune SA, Pu¨schel K, Kluge S. Death after percutaneous dilatational tracheostomy: a systematic review and analysis of risk factors. Crit Care 2013;17:R258. [14] Byhahn C, Lischke V, Meininger D, Halbig S, Westphal K. Perioperative complications during percutaneous tracheostomy in obese patients. Anaesthesia 2005;60:12–5. [15] Nguyen BV, Prat G, Vincent JL, et al. Determination of the learning curve for ultrasound-guided jugular central venous catheter placement. Intensive Care Med 2014;40:66–73. [16] Singh M, Chin KJ, Chan VWS, Wong DT, Prasad GA, Yu E. Use of sonography for airway assessment: an observational study. J Ultrasound Med 2010;29:79–85. [17] Massick DD, Powell DM, Price PD, et al. Quantification of the learning curve for percutaneous dilatational tracheotomy. Layngoscope 2000;110:222–8. [18] Konrad C, Schu¨pfer G, Wietlisbach M, Gerber H. Learning manual skills in anesthesiology: Is there a recommended number of cases for anesthetic procedures? Anesth Analg 1998;86:635–9. [19] Gardiner Q, White PS, Carson D, Shearer A, Frizelle F, Dunkley P. Technique training: endoscopic percutaneous tracheostomy. Br J Anaesth 1998;81:401–3.
Please cite this article in press as: Petiot S, et al. Learning curve for real-time ultrasound-guided percutaneous tracheostomy. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.07.005
ACCPM-207; No. of Pages 5 Anaesth Crit Care Pain Med xxx (2016) xxx–xxx
Original Article
Learning curve for real-time ultrasound-guided percutaneous tracheostomy Sandra Petiot a, Pierre-Gre´goire Guinot a,*, Momar Diouf b, Elie Zogheib a, Herve´ Dupont a a b
Department of anaesthesiology and critical care medicine, Amiens university hospital, place Victor-Pauchet, 80054 Amiens, France Centre de recherche clinique, CHU d’Amiens, 80054 Amiens, France
A R T I C L E I N F O
A B S T R A C T
Article history: Available online xxx
Objectives: The objective of this study was to demonstrate and quantify the ultrasound-guided percutaneous tracheostomy (UPDT) learning curve in a single team since the first UPDT. Study design and patients: This was a cohort of all consecutive patients undergoing UPDT in the Amiens teaching hospital surgical intensive care unit between 2010 and 2014. Methods: The learning process was evaluated according to three aspects: duration of the various steps involved in UPDT, incidence of consecutive complications, and procedure difficulty. Results: During the study period, 85 consecutive patients underwent UPDT with no deaths. The mean total procedure time was 22 (10) minutes (range: 7 to 60). Analysis of mean cumulative UPDT procedure times showed that total UPDT time decreased to a stable duration of 25 minutes after 54 procedures. Complications were observed in 24 (28%) of the 85 patients. The overall complication rate decreased to below a stable percentage of 30% after 70 procedures. The minor complication rate decreased below 25% after 64 procedures. The moderate complication rate decreased to below a stable percentage of 10% after 10 procedures. The major complication rate decreased to below a stable percentage of 5% after 20 procedures. Most complications were observed in the first 50 patients (25 [50%] versus 6 [13%], P < 0.05). Conclusions: Our study demonstrated that UPDT is associated with a fairly long learning curve. At least 50 procedures are necessary to perform UPDT with an acceptable complication rate and procedure time. ß 2016 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Keywords: Ultrasound Percutaneous tracheostomy Learning curve
1. Introduction Since the original description of percutaneous dilatational tracheostomy (PDT) by Ciaglia in 1985, this technique has become increasingly popular [1] and is now commonly used at the bedside in critical care medicine. Since ultrasound (US) has become a widely used tool in the critical care unit, several studies have recently assessed the feasibility of real-time ultrasound-guided tracheostomy [2–4]. Numerous interventional tasks have been reported to be improved by US guidance in the literature, such as real-time US-guided central venous catheter placement [5]. Several studies have demonstrated the safety of real-time US-guided percutaneous tracheostomy (UPDT), even in obese patients [2,3] and have reported low complication rates with no life-threatening complications based on improved visualization of neck anatomy before and during the procedure [2]. However, UPDT is a new * Corresponding author. E-mail address: [email protected] (P.-G. Guinot).
technique, used by only a few teams and no data are available about the UPDT learning curve. The objective of this prospective study was to demonstrate and quantify the UPDT learning curve in a single team. 2. Methods This study included all consecutive patients undergoing PDT in the Amiens teaching hospital surgical intensive care unit between 2010 and 2014. The study was approved by the local ethics committee (Comite´ de protection des personnes Nord Ouest, CHU d’Amiens,1 number 2010/29 and 2014/73), and all patients were provided with written information and gave their informed consent. Exclusion criteria were age under 18 years, clotting disorder (international normalized ratio > 2, activated partial thromboplastin time [APTT] > 1.5, and platelet 1 IRB contact information: Comite´ de protection des personnes, Nord-Ouest II CHU, place V. Pauchet, 80054 Amiens cedex 1.
http://dx.doi.org/10.1016/j.accpm.2016.07.005 2352-5568/ß 2016 Socie´te´ franc¸aise d’anesthe´sie et de re´animation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Please cite this article in press as: Petiot S, et al. Learning curve for real-time ultrasound-guided percutaneous tracheostomy. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.07.005
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ACCPM-207; No. of Pages 5 S. Petiot et al. / Anaesth Crit Care Pain Med xxx (2016) xxx–xxx
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count < 50 109/L), puncture site infection and emergency tracheostomy. 2.1. Percutaneous tracheostomy technique Percutaneous tracheostomy was performed using the singlestep, progressive Ciaglia Blue Rhino technique, as previously described [6,7]. The PCT set consisted of a puncture needle, a guide wire, a small dilator, a curved dilator with a hydrophilic coating and a tracheostomy tube (Tracoe1 expert dilatation set from Pouret Medical, Clichy, France). 2.2. Critical care team The same team composed of two physicians performed each UPDT procedure. Both physicians had more than 5 years of experience with point-of-care US. They also performed other ultrasound-guided invasive procedures such as central venous catheter placement and/or nerve blocks. Both had performed more than 50 PDT procedures according to the modified Ciaglia technique. However, they had no prior experience with the UPDT technique. 2.3. Ultrasound guidance The UPDT procedure was performed at the bedside under deep sedation, analgesia and muscle relaxation using the same US machine and probe (Envisor1 point-of-care system or Cx 50 CompactXtrem with a 12- to 3-MHz linear array probe [Philips Medical Systems, Best, The Netherlands]). The patient was ventilated under controlled ventilation with 100% FIO2. The UPDT procedure required three persons: one person to manage the airway, and two operators performing UPDT. The procedure was always performed according to the same protocol. First, the two operators, in sterile gowns, performed sterile draping of the neck, skin disinfection and sterile draping of the US probe. Point-of-care US was performed at the patient’s bedside. An US examination of the neck area was performed, using transverse and longitudinal views [2]. Transverse sections identified arteries, veins, thyroid, trachea, endotracheal tube and measured skin thickness over the anterior tracheal wall. The longitudinal view identified the various tracheal rings and guided the level of puncture. After this step, the physician standing at the patient’s head withdrew the endotracheal tube balloon to near the vocal cords under direct laryngoscopic guidance. The modified Ciaglia technique under ultrasound guidance was then initiated using a modified Blue Rhino dilator Tracoe1 (Pouret medical, Clichy, France) [1]. A puncture needle with a saline-filled syringe was introduced perpendicularly to the skin and advanced until the needle was seen to pass the anterior tracheal wall during inspiration. The needle was then angled caudally to prevent retrograde passage of
the guide wire. The needle was visualized in ‘‘out-of-plane’’ mode (i.e., the needle path was determined by the presence of a distinct acoustic shadow ahead of the needle) on a transverse section of the neck. The guide wire was introduced, the needle was removed, and a small horizontal incision was made at the point of puncture. The guide wire was visualized as a hyperechoic signal on transverse and longitudinal sections. The small dilator was then used to create the initial stoma, followed by the single-stage curve dilator over the guide wire. The tracheostomy tube fitted over an appropriate loading tube was passed through the stoma. US guidance allowed the operator to check the correct positioning of the puncture site and guide wire before dilatation of the trachea followed by tracheostomy tube placement. 2.4. Data collection Demographic and clinical data were collected, including gender, age (years), height (metres), weight (kilograms), body mass index (BMI), Simplified acute physiology score II (SAPS II), admission diagnosis, duration of mechanical ventilation prior to PCT (days), and indication for tracheostomy. An anatomical criterion of difficult tracheostomy was noted: presence of a short neck. The following US data were also recorded: level of the thyroid, presence of tracheal deviation, aberrant vessels, puncture site, subcutaneous tissue thickness (centimetres) defined by the distance between the skin and the anterior tracheal wall measured perpendicularly to the skin at the puncture site, tracheal diameter (centimetres). The difficulty of the US-guided technique was scored on a simple numerical scale; 1: easy; 2: minor difficulties in identifying anatomical structures and tracheostomy tube placement; 3: moderate difficulties in identifying anatomical structures; 4: very difficult; and 5: impossible [2]. 2.5. Definition of complications Complications occurring between the beginning of UPDT and decannulation were recorded. Bronchoscopy was performed before decannulation in order to detect any long-term complications. Complications were classified in two ways: according to their severity as minor (irrelevant for the patient), moderate (potentially harmful) and major complications (harmful and requiring immediate treatment) (Table 1); according to their chronology as technical, intra-procedural and post-procedural [2]. 2.6. Construction of the learning curve The learning curve was based on three aspects of UPDT. First, we evaluated the duration of the various steps of UPDT: installation
Table 1 Classification of complications. SpO2, oxygen saturation as measured by pulse oximetry. Minor
Moderate
Major
Bleeding not requiring compression or administration of packed red blood cells Hypoxaemia (SpO2 of less than 90%) and/or hypotension (systolic blood pressure less than 100 mmHg) for less than 5 minutes Difficult puncture or multiple punctures (more than three) Puncture of the tracheal tube cuff Peristomal infection not requiring antibiotic therapy
Bleeding requiring compression without blood transfusion Posterior tracheal wall injury not requiring surgical repair
Bleeding requiring administration of packed red blood cells
Atelectasis Tracheal ring fracture
Subglottic stenosis Granuloma Malposition of the tracheostomy tube (pretracheal or paratracheal insertion)
Oesophageal injury
Posterior tracheal wall injury requiring surgical repair Pneumothorax Peristomal infection requiring local care or antibiotic therapy or both Loss of airway Surgical conversion Cardiac arrest Death
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time (minutes), duration of tracheostomy defined by the time (minutes) between puncture of the trachea and ventilation of the patient. Secondly, we assessed the incidence of consecutive complications (Table 1). The ‘‘acceptable rate’’ was defined on the basis of the results of various studies evaluating percutaneous tracheostomy [8–10]. The incidence of each category of complication was defined (minor: 30%, moderate: 10%, major: 5%) [8– 14]. Thirdly, we evaluated the time-course of the difficulty of performing UPDT based on a scale. 2.7. Statistical analysis Variable distributions were assessed using the D’AgostinoPearson test. Data were expressed as means (SD), medians (25– 75 percentiles) or numbers (percentage). To construct learning curves, data were arranged in chronological order. The cumulative proportion (for qualitative variables) and the cumulative mean (for quantitative variables) were computed after each new tracheotomy procedure. The learning curve was plotted with the cumulative number of tracheotomies on the X-axis and the cumulative proportion or cumulative mean on the Y-axis, as appropriate. The horizontal line defined by the target value of cumulative proportion or cumulative mean was added to the plot. A simpler analysis of complication rates, comparing the first 50 patients and subsequent patients, was also performed. Complication rates were analysed by comparing sequential cohorts using Fisher’s exact tests. All statistical analyses were performed with open-source R.3.1.0 software. 3. Results During the study period, 85 consecutive patients with a mean age of 57 [8] years underwent UPDT. All UPDTs were performed successfully with no deaths in this series. The median level of puncture was situated between the 2nd and 3rd tracheal rings. Patient characteristics are provided in Table 2. In this series of 85 patients, 43 (51%) were medical intensive patients (respiratory failure secondary to chronic obstructive pulmonary disease, acute respiratory syndrome, pneumonia, stroke, seizures, acute heart failure, cardiac arrest, etc.), and 42 (49%) were surgical intensive patients (cardiac, vascular or digestive surgery, or severe trauma). 3.1. Time of procedure The mean total procedure time was 22 [12] minutes (range: 7 to 60 minutes). The mean duration of sterile draping and US
Table 2 Patient characteristics. Male/female Age (years) Weight (kg) Height (m) BMI SAPS II Mechanical ventilation before UPDT (days) Anatomical characteristics Short neck Thyroid goitre Neck trauma Ultrasound characteristics Tracheal diameter (cm) Subcutaneous tissue thickness (cm) Aberrant vessels
61/24 57 (6) 87 (23) 1.7 (0.1) 30.5 (8) 44 (14) 24 (9) 39 (46%) 11 (13%) 2 (2%) 2.04 (0.47) 1.15 (0.52) 36 (42%)
Values are expressed as means (SD) or numbers (percentage). BMI: body mass index; SAPS II: simplified acute physiology score II; UPDT: ultrasound-guided percutaneous dilatational tracheostomy; COPD: chronic obstructive pulmonary disease.
Fig. 1. Cumulative mean total time according to the number of UPDTs. The line represents stabilization of the cumulative mean total time.
landmarking before incision was 11 [8] minutes. The mean time from incision to fixation was 10 [8] minutes. Analysis of the cumulative mean total UPDT time showed that the total UPDT time decreased to a stable duration of 25 minutes after 54 procedures (Fig. 1). The same analysis of cumulative mean UPDT time from incision to fixation showed that the mean time decreased to below a stable duration of 11 minutes after 68 procedures. 3.2. Complications Complications were observed in 24 (28%) of the 85 patients. The cumulative number of complications was 31, with 24 minor complications, 6 intermediate complications and one major complication. Five patients presented more than one complication (4 patients with two complications and 1 patient with five complications). Minor complications were tracheal ring fracture (n = 2), puncture of the tracheal tube cuff (n = 8), minor bleeding (n = 7), desaturation or hypotension lasting less than 5 minutes (n = 5) and multiple punctures (n = 2). Moderate complications were granulomas (n = 3) and bleeding requiring compression (n = 3). The major complication consisted of a peristomal infection, requiring antibiotic therapy. Most complications were observed in the first 50 patients (25 [50%] versus 6 [13%] complications, P < 0.05). The overall complication rate decreased to below a stable percentage of 30% after 70 procedures. The minor complication rate decreased to below 25% after 64 UPDTs (Fig. 2A). The moderate complication rate decreased to below a stable percentage of 10% after 10 UPDTs (Fig. 2B). The major complication rate decreased to below a stable percentage of 5% after 20 procedures (Fig. 2C). 3.3. Procedure difficulty The mean score was 2 (0.8) with 39 (46%) procedures scored as 1, 28 (33%) scored as 2, 17 (20%) scored as 3, and 1 (1%) scored as 4, with no failed procedures. UPDT difficulty stabilized between a score of one and two after 25 procedures. 4. Discussion This is the first study to evaluate the UPDT learning curve. Based on our cohort, at least 50 UPDTs are necessary to achieve an acceptable complication rate and procedure time.
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Fig. 2. Cumulative incidence of complications according to the number of UPDTs: the line represents the stable 30% complication rate. The same analysis was performed for the minor complication rate with a stable rate of 25% (graph A), the moderate complication rate with a stable rate of 10% (graph B) and the major complication rate with a stable rate of 5% (graph C). UPDT: ultrasound-guided percutaneous dilatational tracheostomy.
Determination of the learning curve of a procedure must take into account various aspects of the procedure. We therefore based our analysis on 3 different criteria: procedure time, complication rates and procedure difficulty. This approach was used by Nguyen et al. to determine the learning curve for ultrasound-guided jugular central venous catheter placement [15]. The number of procedures required for catheter placement mastery was smaller than for UPDT (at least 20), but UPDT requires more training compared to a simple ultrasound-guided puncture. One finding of this study was that the real-time ultrasoundguided procedure was not as simple as expected. A rather long learning phase was required to decrease the complication rate and procedure time. In order to identify neck structures, the operator must choose the level of puncture and learn US anatomy of the neck as described by Singh et al. [16]. For example, the presence of air in the trachea, which is a poor US conductor, makes it difficult to identify the needle tip or the extremity of the endotracheal tube. At the beginning of the series, this poor visualization was responsible for tracheal cuff punctures because of incomplete US-guided tube removal. The incidence of tracheal cuff puncture subsequently decreased. Several other procedures are performed under US for UPDT: needle puncture, guide and dilator introduction in 2 dimensions (longitudinal and transverse). Nevertheless, our results are similar to those reported by Massick et al. [17], who found similar rates of the same complications but with not exactly the same list of events. Massick’s study is also the only study to assess the learning curve for percutaneous dilatational tracheostomy without ultrasound and bronchoscopic guidance. They based their learning curve exclusively on a decreasing complication rate and found that 20 procedures were necessary. A greater number of procedures was required to decrease the overall complication rate in our study, but differences in the definition and classification of complications make it difficult to compare results [2,17]. The target percentages were chosen after analysis of the literature on the complications of percutaneous dilatational tracheostomy [8–12], based on a very detailed inventory of events, as described by Byhahn to optimally assess the complications associated with PCT [14]. Even the minor complication rate may appear to be high; most of these complications were recorded in order to allow comparison with other studies. The clinical significance of bleeding less than 5 mL not requiring compression, or tracheal cuff puncture can be questioned as they have no consequences for the patient. The minor complication rate was therefore inevitably high and difficult to decrease. A previous study demonstrated that the learning curves associated with various manual skills in anaesthesiology varied greatly between procedures: orotracheal intubation required 57 procedures, while epidural anaesthesia required up to 90 procedures [18]. Learning a procedure is a complex process
dependent on many factors such as the learning environment or inter-individual variations. We chose to describe the UPDT learning curve performed by a single team in order to limit these biases. The definition of a procedure learning curve is very important in order to adapt training. A large number of procedures are required in order to master the ultrasound guidance of percutaneous tracheostomy, but it is difficult to perform all of these procedures over a short period of time because tracheostomies are not performed on a daily basis in the ICU. A recent French survey suggested that an intensivist performed between 2 and 4 tracheostomies per month [6], suggesting that the development of simulation training would be the best non-invasive way to ensure the proper acquirement of a new skill, as demonstrated for emergency cricothyrotomy [7]. Moreover, simulation complies with the precept: ‘‘never the first time on the patient’’. Percutaneous tracheostomy training has been previously developed on a pig model, but this model is unsuitable for repeated procedures [19]. A UPDT phantom therefore needs to be developed to allow simulation training on a model and technique sharing. The study has a number of limitations. First, the learning curve may apply only to the study team and the percutaneous dilatational technique. It could vary among ICU teams, depending on their experience with ultrasound and the percutaneous dilatational technique. A larger study must be conducted to confirm these results. Second, to be reproducible, studies must use a standardized classification of complications. One difficulty concerns the definition of complications. An abundant literature has been published on PCT and complications [2,8–14]. However, most of larger studies are retrospective with several definitions of complications. Consensual definitions must be used in order to allow comparison between studies. To facilitate such comparison, we chose to use previously published definitions [2]. Thirdly, the number of procedures required to master UPDT may appear to be high, but it must be remembered that this study concerned a new procedure with no previous description of limitations. The learning curve only concerned the development of the real-time ultrasound-guided technique: the team had no experience with UPDT before the beginning of the study but a good prior experience of the Ciaglia technique without ultrasound and the use of ultrasound guidance (for catheter placement or nerve blocks). Our results reflect the difficulty of performing a new procedure at the bedside. As indicated above, tracheal cuff puncture was frequent at the beginning of our experience due to the difficulty of identifying the tracheal cuff by ultrasound [2]. 5. Conclusion In conclusion, our study demonstrated the existence of a fairly long UPDT learning curve. At least 50 UPDT procedures are
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necessary to achieve an acceptable complication rate and procedure time. Finally, a UPDT simulation-training programme should be developed. Funding No external funding received. Disclosure of interest The authors declare that they have no competing interest. Acknowledgements None. References [1] Ciaglia P, Firsching R, Syniec C. Elective percutaneous dilatational tracheostomy. A new simple bedside procedure; preliminary report. Chest 1985;87: 715–9. [2] Guinot PG, Zogheib E, Petiot S, Marienne JP, Guerin AM, Monet P, et al. Ultrasound-guided percutaneous tracheostomy in critically ill obese patients. Crit Care 2012;16:R40. [3] Rajajee V, Fletcher JJ, Rochlen LR, Jacobs TL. Real-time ultrasound-guided percutaneous dilatational tracheostomy: a feasibility study. Crit Care 2011; 15:R67. [4] Rudas M, Seppelt I. Safety and efficacy of ultrasonography before and during percutaneous dilatational tracheostomy in adult patients: a systematic review. Crit Care Resusc 2011;14:297–301. [5] Karakitsos D, Labropoulos N, De Groot E, et al. Real-time ultrasound-guided catheterisation of the internal jugular vein: a prospective comparison with the landmark technique in critical care patients. Crit Care 2006;10:R162.
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[6] Blondonnet R, Chabanne R, Godet T, et al. Tracheostomy in French ICUs and patient outcome: National opinion survey. Ann Fr Anesth Reanim 2014; 33:227–323. [7] Hubert V, Duwat A, Deransy R, Mahjoub Y, Dupont H. Effect of simulation training on compliance with difficult airway management algorithms, technical ability, and skills retention for emergency cricothyrotomy. Anesthesiology 2014;120:999–1008. [8] Gobatto AL, Besen BA, Tierno PF, et al. Comparison between ultrasound- and bronchoscopy-guided percutaneous dilational tracheostomy in critically-ill patients: a retrospective cohort study. J Crit Care 2015;30:e13–7. [9] Cianchi G, Zagli G, Bonizzoli M. Comparison between single-step and balloon dilatational tracheostomy in intensive care unit: a single-centre, randomized controlled study. Br J Anaesth 2010;6:728–32. [10] Fikkers BG, Staatsen M, van den Hoogen FJ, van der Hoeven JG. Early and late outcomes after single step dilatational tracheostomy versus the guide wire dilating forceps technique: a prospective randomized clinical trial. Intensive Care Med 2011;37:1103–9. [11] Hatfield A, Bodenham A. Portable ultrasonic scanning of the anterior neck before percutaneous dilatational tracheostomy. Anaesthesia 1999;54:660–3. [12] Sustic´ A, Kovac D, Zgaljardic´ Z, Zupan Z, Krstulovic´. Ultrasound-guided percutaneous dilatational tracheostomy: a safe method to avoid cranial misplacement of the tracheostomy tube. Intensive Care Med 2000;26:1379–81. [13] Simon M, Metschke M, Braune SA, Pu¨schel K, Kluge S. Death after percutaneous dilatational tracheostomy: a systematic review and analysis of risk factors. Crit Care 2013;17:R258. [14] Byhahn C, Lischke V, Meininger D, Halbig S, Westphal K. Perioperative complications during percutaneous tracheostomy in obese patients. Anaesthesia 2005;60:12–5. [15] Nguyen BV, Prat G, Vincent JL, et al. Determination of the learning curve for ultrasound-guided jugular central venous catheter placement. Intensive Care Med 2014;40:66–73. [16] Singh M, Chin KJ, Chan VWS, Wong DT, Prasad GA, Yu E. Use of sonography for airway assessment: an observational study. J Ultrasound Med 2010;29:79–85. [17] Massick DD, Powell DM, Price PD, et al. Quantification of the learning curve for percutaneous dilatational tracheotomy. Layngoscope 2000;110:222–8. [18] Konrad C, Schu¨pfer G, Wietlisbach M, Gerber H. Learning manual skills in anesthesiology: Is there a recommended number of cases for anesthetic procedures? Anesth Analg 1998;86:635–9. [19] Gardiner Q, White PS, Carson D, Shearer A, Frizelle F, Dunkley P. Technique training: endoscopic percutaneous tracheostomy. Br J Anaesth 1998;81:401–3.
Please cite this article in press as: Petiot S, et al. Learning curve for real-time ultrasound-guided percutaneous tracheostomy. Anaesth Crit Care Pain Med (2016), http://dx.doi.org/10.1016/j.accpm.2016.07.005