Randomized comparison of three transducer orientation approaches for ultrasound guided internal jugular venous cannulation

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1 British Journal of Anaesthesia, 116 (3): (2016) doi: /bja/aev399 Advance Access Publication Date: 24 December 2015 Clinical Practice Randomized comparison of three transducer orientation approaches for ultrasound guided internal jugular venous cannulation M. Batllori 1, *, M. Urra 1, E. Uriarte 1, C. Romero 1, J. Pueyo 2, L. López-Olaondo 2, K. Cambra 3 and B. Ibáñez 3 1 Department of Anaesthesiology, Complejo Hospitalario de Navarra, Calle Irunlarrea 3, Pamplona 31008, Spain, 2 Department of Anaesthesiology, Clínica Universidad de Navarra, Facultad de Medicina, Universidad de Navarra, Pamplona, Spain, and 3 Navarrabiomed Fundación Miguel Servet, Red de investigación en servicios sanitarios y enfermedades crónicas (REDISSEC), Pamplona, Spain *Corresponding author. mikelbat.anestesia@gmail.com Abstract Background: Ultrasound-guided internal jugular venous access increases the rate of successful cannulation and reduces the incidence of complications, compared with the landmark technique. Three transducer orientation approaches have been proposed for this procedure: short-axis (SAX), long-axis (LAX) and oblique-axis (OAX). Our goal was to assess and compare the performance of these approaches. Methods: A prospective randomized clinical trial was conducted in one teaching hospital. Patients aged 18 yr or above, who were undergoing ultrasound-guided internal jugular cannulation, were randomly assigned to one of three intervention groups: SAX, LAX and OAX group. The main outcome measure was successful cannulation on first needle pass. Incidence of mechanical complications was also registered. Restricted randomization was computer-generated. Results: In total, 220 patients were analysed (SAX n=73, LAX n=75, OAX n=72). Cannulation was successful on first needle pass in 51 (69.9%) SAX patients, 39 (52%) LAX patients and 53 (73.6%) OAX patients. First needle pass failure was higher in the LAX group than in the OAX group (adjusted OR 3.7, 95% CI , P=0.002). A higher mechanical complication rate was observed in the SAX group (15.1%) than in the OAX (6.9%) and LAX (4%) groups (P=0.047). Conclusions: As OAX showed a higher first needle pass success rate than LAX and a lower mechanical complications rate than SAX, we recommend it as the standard approach when performing ultrasound-guided internal jugular venous access. Further clinical studies are needed to confirm this conclusion. Clinical trial registration: NCT Key words: catheterization, central venous; clinical trial; jugular veins; ultrasonography, interventional Internal jugular venous cannulation (IJVC) is commonly performed in the operating room and critical care settings. The traditional approach to IJVC is based on anatomical landmarks, but current evidence-based recommendations state that ultrasound should be used whenever possible to guide this procedure. 1 3 This increases the success rate, reduces the time and number of attempts until successful cannulation and reduces the incidence of mechanical complications when compared with the Accepted: October 5, 2015 The Author Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please journals.permissions@oup.com 370

2 Comparison of three views for US-guided IJV access 371 Editor s key points Several approaches to cannulation of the internal jugular vein have been described. This study compared three ultrasound guided approaches to internal jugular venous cannulation in experienced operators. Ultrasound guidance using an oblique-axis approach was associated with higher success rate and fewer complications than short or long axis approaches. Further studies are required to confirm these findings. traditional landmark technique. 45 Although ultrasound scanning of the targeted vessel before performing needle insertion without ultrasound control (ultrasound assistance) may be helpful, 5 real-time ultrasound control of the needle tip during the actual vascular puncture (ultrasound guidance) is the gold standard of practice. 12 Different imaging approaches have been described. 6 8 The short-axis approach (SAX) allows simultaneous visualization of both artery and vein, but can make needle tip control difficult. 910 The long-axis approach (LAX) can optimize needle visualization, but it can be challenging to perform owing to certain anatomical limitations (such as neck length). Additionally, LAX only displays the vein in the ultrasound image (unless the artery lies directly underneath) and if the operator strays medially, accidental arterial cannulation can occur. 9 The oblique-axis approach (OAX) tries to take advantage of the strengths of both previous approaches using a probe alignment that is midway between SAX and LAX, and combines it with an in-plane needle insertion in which the needle is advanced from lateral to medial. 6 Thus, the OAX optimizes visualization of both the needle and the jugular vein with all its surrounding structures. The purpose of the present study was to assess and compare the performance of these approaches (SAX, LAX and OAX) in terms of cannulation success and incidence of complications. Our primary hypothesis was that OAX was a better approach than SAX or LAX. Methods This study was designed as a prospective randomized controlled trial and included patients who underwent IJVC at the Navarra Hospital Complex, Pamplona, Spain. It was approved by the Ethical Committee for Clinical Investigations, Navarra Health Department (project number 95/11), and was registered with Clinicaltrials.gov (NCT ). Written informed consent was obtained from all participants before they were included in the study. The day before IJVC was to be performed, patients (aged 18 or above) in whom IJVC had been indicated were asked to participate in the study. Patients who did not meet any exclusion criteria (as listed in Table 1) were included. All the cannulations were performed by three anaesthetists with appropriate proficiency in ultrasound-guided central venous access. All of them underwent a structured training programme that included a two-hour lecture, a one-hour bedside teaching session on identifying the internal jugular vein and its surrounding structures using SAX, LAX and OAX, and a onehour supervised puncture practice session using an ultrasound phantom in which in-plane and out-of-plane needle insertion techniques were reviewed. For all practical sessions an S-Nerve ultrasound machine (SonoSite, Bothell, WA) with a 13 6 MHz 38-mm linear array probe was used - the same equipment that Table 1 Patient exclusion criteria Age <18 yr History of previous surgical intervention at the cannulation site Presence of a central venous catheter during the past 72 h (in the same vein in which the present cannulation was planned) Infection signs or subcutaneous haematoma close to the puncture site Recent cervical trauma with present neck immobilization Analytical data suggesting severely altered haemostasis (INR >2, platelet count <50.000) Subcutaneous emphysema with cervical extension Agitated or uncooperative patient Cannulation planned to be performed outside of the surgical area Cannulation indicated during emergency surgery or immediately before it was used on the study subjects. Additionally, investigators were required to have performed at least ten successful supervised ultrasound-guided IJVC procedures, using each of the three approaches (LAX, SAX and OAX) before participating in the study, to ensure their proficiency with all of them. 11 Restricted randomization was performed using a random number list that had been computer-generated for each cannulator before the study commenced. Patients were randomly assigned (1:1:1) to have their cannulation performed SAX, LAX or OAX. Every IJVC took place in the operating room or in the post-anaesthesia care unit. Patients were placed in a supine position. Standard monitoring (ECG, non-invasive arterial pressure, pulse oximetry) was carried out during the procedure for all patients, and supplementary oxygen was delivered via a nasal cannula in awake patients. Before preparation of the skin, a pre-procedural ultrasound exam was performed to verify internal jugular vein patency, and its diameter was measured. Once the side had been chosen, the cannulation was performed following a sterile technique. Lidocaine 2% was used to anaesthetize the puncture site in awake patients. All the procedures were performed by a modified Seldinger technique, using a 18-Ga, 6.5 cm introducer needle (Arrow International, Reading, PA) with a 5 ml syringe attached to it. The vascular puncture was performed under ultrasound guidance, using a single-person technique (with the same operator handling the transducer and the needle). With SAX, the transducer was placed transversally over the neck (parallel to the clavicle), and once the vein was visible in the middle of the ultrasound image the needle was introduced in a plane perpendicular to the long axis of the transducer (Fig. 1A). With LAX, the transducer was placed longitudinally over the neck, and once the vein was identified the needle was inserted just underneath the footprint of the probe following its long axis from cranial to caudal (Fig. 1B). With OAX, the operator first obtained a short-axis view of the vein and then rotated the transducer to a position midway between the SAX and LAX views, inserting the needle just underneath the footprint of the probe, following its long axis from lateral to medial (Fig. 1C). Video recordings of the standardized procedures for SAX, LAX and OAX cannulations were made available to the investigators to enhance their adherence to the study

3 372 Batllori et al. Fig 1 Photographs of ultrasound transducer orientation and needle insertion with corresponding ultrasound images. All cannulations were performed from cranial to caudal in the cervical region. (A) Short-axis approach. (B) Long-axis approach. (C) Oblique-axis approach. (a) Common carotid artery. (v) Internal jugular vein. (arrows) Needle tip. protocol. Once the needle tip was identified inside the vein, the syringe was removed before a J-wire was introduced through the needle. After identifying the guidewire inside the jugular vein in a long-axis ultrasound examination, the Seldinger technique was continued until catheter insertion. After the catheter was fixed in place, a chest radiograph was conducted to verify the correct catheter tip position and check for other mechanical complications. A cannulation was considered to be successful in the designated approach if the guidewire was advanced without resistance and ultrasonographically detected inside the jugular vein. A cannulation was considered unsuccessful if it had to be performed using an approach that differed from that to which the patient had been randomized, or if the cannulation time (from the moment the Seldinger needle first pierced the skin, to the moment when the guidewire was advanced into the vein without resistance), exceeded 180 s, even if success was achieved in any such patients. The primary outcome measure of the study was first needle pass cannulation success. A needle pass was considered as such if the Seldinger needle was advanced forward without any backward movement. Every successive needle withdrawal with subsequent advance was considered another needle pass, whether or not a new skin puncture site was chosen. Secondary outcome measures were number of needle passes until successful cannulation, cannulation time measured in s, incidence of mechanical complications (detected during or after the procedure) and incidence of catheter-related bloodstream infection. Patients were followed up until the point of catheter withdrawal, and all catheter tips were sent for culture. Expected mechanical complications were: arterial puncture (defined as any pulsatile blood reflux through the needle observed during the procedure), posterior venous wall puncture (ultrasonographical identification of the needle tip or guidewire at any place deeper than the posterior wall of the internal jugular vein during cannulation attempts), local haematoma, puncture site bleeding (presence of bleeding that persisted after two minutes of active haemostatic compression), catheter misplacement (catheter tip identified at any place other than the superior vena cava in the control chest radiograph), pneumothorax and haemothorax. To estimate the sample size required, we assumed a 60% proportion of first-needle-pass cannulation success in SAX group as found by Milling and co-workers, 5 and set an alpha-level of 0.05 and a beta-level of Our study, with 70 patients per group, was thus powered to find as statistically significant differences in the proportions between groups of around 20%. Patient characteristics and outcome measures data are presented using number and percentages for categorical variables and mean (SD) for quantitative variables. Comparisons between groups were conducted using ANOVA, Kruskal-Wallis, χ 2 test or exact Fisher tests, depending on the nature of the variables. As a complementary method, multivariate analysis to control for possible confounders was conducted using logistic and linear regression (depending on the nature of the response variable). P-values of <0.05 were considered statistically significant. All statistical analyses were computed using IBM SPSS Statistics 21.0 software (IBM Corporation, USA). Results In total, 220 patients were randomized between April 2012 and March 2013 (Fig. 2). Analysis was conducted according to the intention-to-treat principle. Patient characteristics and baseline characteristics did not differ significantly between study groups (Table 2). Univariate analysis results are presented in Table 3. Overall cannulation success rate in the designated approach was 96.4%, with no differences between groups. Eight IJVC procedures were considered unsuccessful because either cannulation time was longer than 180 s (five patients: one SAX, two LAX, two OAX) or the investigator decided to switch to another approach (three patients: one SAX, two OAX). All eight patients underwent right-side jugular cannulations, whilst anaesthetized. Reasons

4 Comparison of three views for US-guided IJV access 373 Eligible patients (n=231) Excluded (n=11) Fig 2 CONSORT diagram. Short-axis cannulation (n=73) Cannulators performing the intervention (n=3) Cannulator A: 36 patients Cannulator B: 20 patients Cannulator C: 17 patients Underwent randomization (n=220) Randomization Long-axis cannulation (n=75) Cannulators performing the intervention (n=3) Cannulator A: 38 patients Cannulator B: 19 patients Cannulator C: 18 patients Did not consent (n=5) Study cannulator not available (n=5) Change in planned surgery, central venous access not indicated (n=1) Oblique-axis cannulation (n=72) Cannulators performing the intervention (n=3) Cannulator A: 36 patients Cannulator B: 19 patients Cannulator C: 17 patients Analysed (n=73) Analysed (n=75) Analysed (n=72) for prolonged cannulation time included difficulty in advancing the guidewire in SAX, difficulty in identifying the needle in LAX, and difficulty in piercing the vein wall in OAX. Changes in transducer orientation approach were all related to difficulty in guidewire advance. All IJVC procedures (100%) had a successful outcome, and they were performed on the side the investigator had chosen initially. First needle pass cannulations differed between groups in a univariate comparison, and a multivariate analysis confirmed that the success rate of first needle passes was lower in LAX than in both OAX (OR 3.70; 95% CI 1.71, 8.0) and SAX (OR 2.37; 95% CI 1.16, 4.86). No significant differences were observed between SAX and OAX. Differences were also found in the mean number of needle passes until successful cannulation. Patients in the LAX group required more needle passes than patients in the OAX group (OR 3.85; 95% CI 1.81, 8.20) and SAX group (OR 2.27; 95% CI 1.14, 4.54). There were no significant differences between SAX and OAX. Mean cannulation time was greater in LAX than in SAX and OAX. We identified a significant difference between LAX and SAX with a mean difference of s (95% CI 2.26, 21.12). No other differences were found. The number of patients developing mechanical complications differed between groups, with a significantly higher rate of complications in the SAX group (P=0.047). 21 mechanical complications occurred in 19 patients. The most frequently detected complication was posterior venous wall puncture (PVWP), and its incidence was greater in the SAX group (P=0.001). The other complications that developed were minor, and evenly distributed

5 374 Batllori et al. among groups. Neither arterial punctures nor any severe mechanical complications were detected in any group. Bacterial colonization was detected in 13.9% of the catheter tip cultures with no differences between groups. Two catheterrelated bloodstream infections attributable to IJVC were detected, both in LAX. No differences were found in the rate of complications between chosen cannulation sides. Finally, no statistical differences were detected between cannulators regarding success rate, number of needle passes, cannulation time or complication rate. Table 2 Patient baseline characteristics (recorded immediately before jugular cannulation). Data shown as mean (SD) or number and % of patients, except for age which is shown as mean (range). IJV, internal jugular vein; SAX, short axis; LAX, long axis; OAX, oblique axis SAX (n=73) LAX (n=75) OAX (n=72) Age (yr) 64.9 (63) 64.0 (64) 65.2 (67) Sex n (%) Females 28 (38.4) 26 (34.7) 29 (40.3) Males 45 (61.6) 49 (65.3) 43 (59.7) BMI (kg m 2 ) 27.7 (4.8) 27.3 (4.1) 27.2 (4.6) Sternomental distance 12.7 (2.5) 12.4 (2.6) 12.9 (2.5) (cm) Sternomandibular 13.4 (2.8) 13.5 (2.9) 13.6 (2.8) distance (cm) Neck circumference (cm) 41.2 (5.1) 40.7 (5.0) 40.5 (5.2) Cannulated IJV diameter 1.20 (0.3) 1.23 (0.3) 1.10 (0.2) (cm) Anticoagulation n (%) No 46 (63) 56 (74.7) 56 (77.8) Present 1 (1.4) 1 (1.3) 3 (4.2) Suspended 26 (35.6) 18 (24) 13 (18) Antiaggregation n (%) No 58 (79.5) 52 (69.3) 53 (73.6) Present 11 (15) 14 (18.7) 17 (23.6) Suspended 4 (5.5) 9 (12) 2 (2.8) Patient status n (%) Anaesthetized 64 (87.7) 65 (86.7) 63 (87.5) Awake 9 (12.3) 10 (13.3) 9 (12.5) Discussion OAX and SAX had higher first needle pass success rates and required fewer needle passes and less time when compared with LAX. Differences were observed in the rates of mechanical complications, with the incidence of PVWP being significantly higher in SAX. Our randomized controlled clinical trial is the first one designed to compare the performance of three transducer orientation approaches (SAX, LAX and OAX) for ultrasound-guided internal jugular venous access. SAX has traditionally been the approach preferred by clinicians for performing and teaching ultrasound-guided IJVC. Most clinical studies have been conducted using this particular transducer orientation approach, which uses the transverse view for vascular imaging combined with an out-of-plane needle approach. Our results regarding number of needle passes, cannulation time and rate of complications in SAX coincide with those of a range of studies LAX is currently considered to be the recommended approach when performing ultrasound-guided vascular access procedures, as an in-plane needle insertion can lead to more precise needle tip control. 12 Evidence from experimental studies that have compared SAX and LAX approaches in inanimate models supports this statement, 14 showing that needle tip visualization can be more difficult with out-of-plane needle insertion Experimental evidence shows that PVWP occurs more frequently with SAX. 17 A few clinical studies have evaluated LAX, and the results of these studies are comparable with those of our own study regarding LAX. Studies comparing transducer orientation approaches for ultrasound-guided IJVC in the clinical setting are scarce This is the first trial to clinically evaluate the oblique-axis approach. Our results showed that OAX and SAX had higher rates of successful first needle pass cannulations compared with LAX. Cannulation time was greater with LAX than with SAX, but we have to consider that this difference, although statistically significant, may have no clinical significance. The overall incidence of mechanical complications was higher in our study than in previous ultrasound-guided IJVC studies. This can be explained by the fact that PVWP was considered as a complication, because under certain circumstances it can expose patients to an increased risk of developing mechanical complications. Previous clinical studies have not attempted to estimate the incidence of PVWP, although an experimental study using ultrasound phantoms suggested that it can be as high as 31% with SAX and 37% with LAX, and is not related to operator Table 3 Differences in quality and safety outcomes between transducer orientation approaches: univariate analysis. Data shown as mean (SD) or number and % of patients. IJV, internal jugular vein; SAX, short axis; LAX, long axis; OAX, oblique axis. χ 2 test; exact Fisher test; Kruskal-Wallis SAX (n=73) LAX (n=75) OAX (n=72) P-value Successful cannulation with the designated approach n (%) 71 (97.3) 73 (97.3) 68 (94.4) First needle pass success n (%) 51 (69.9) 39 (52) 53 (73.6) Number of needle passes 1.51 (0.97) 1.92 (1.36) 1.37 (0.84) Cannulation time (s) 35.0 (23.4) 46.1 (36.3) 41.2 (23.9) Patients developing at least one mechanical complication n (%) 11 (15.1) 3 (4) 5 (6.9) Posterior IJV wall puncture n (%) 8 (11) 0 (0) 1 (1.4) Puncture site bleeding n (%) 2 (2.7) 1 (1.3) 0 (0) Local cervical haematoma n (%) 1 (1.4) 2 (2.7) 2 (2.8) Catheter misplacement n (%) 0 (0) 2 (2.7) 2 (2.8) Catheter-related bloodstream infection n (%) 0 (0) 2 (2.7) 0 (0) 0.330

6 Comparison of three views for US-guided IJV access 375 experience. 19 The incidence of PVWP in our study was lower [eight patients (11%) with SAX and one patient (1.4%) with OAX] and not operator-related. All PVWP patients were detected after finding resistance to guidewire advance, even though the operator had initially identified the needle tip in the internal jugular lumen. Ultrasound examinations at this point revealed that the guidewire had passed through both walls of the vein, with its J-tip in an extravascular location immediately under the posterior venous wall. Under ultrasound guidance we managed to withdraw the guidewire until the J-tip was identified inside the jugular vein, and then proceeded to advance it through the vein without creating a new puncture. This situation has been previously described by Blaivas in a case report. 20 This author attributed PVWP in these cases to errant movement of the needle, which may impact its tip against the posterior wall of the vein. It could be possible to consider an alternative mechanism that would account for PVWP. When using a single operator technique for ultrasound-guided IJVC, theoperatorsetsasidethetransducerprobeoncebloodreflux is obtained. The light pressure that is inevitably applied to the patient disappears upon withdrawal of the transducer, and elastic retraction forces from the tissues surrounding the vein, can lead to the posterior wall of the vein impacting against the needle bevel, if the latter is in the lower part of the vascular lumen. Although we cannot demonstrate this hypothesis with the data from our study, we consider that it merits further investigation. Eliminating PVWP from our complications list, the mechanical complication rate is similar to that reported in other studies All of our mechanical complications were minor, and no patients with accidental arterial puncture were registered. In our study, OAX was more effective than SAX in avoiding PVWP, which could make it preferable to SAX. This conclusion concords with the results of an experimental study that explored ultrasound phantoms. 21 Our study has some limitations. In the recruitment phase, one of the conditions of being able to participate as a cannulator, was to have achieved accredited proficiency in ultrasoundguided IJVC. This could make its results only extrapolative to experienced operators. Differences in the ability of each cannulator to manage each of the three approaches have also to be considered as a possible source of bias, which we have tried to minimize, ensuring that we used experienced cannulators for each of the three techniques. Nonetheless, no differences were detected between cannulators regarding their quality and safety cannulation outcomes. In addition, the incidence of PVWP in our study could potentially have been underestimated, as all the patients were diagnosed only after identifying a misplaced guidewire using ultrasound. As the only criterion to consider the needle tip position as intravascular at the point of transducer removal was the operator s opinion, we cannot exclude patients with inadvertent PVWP related to incorrect needle tip visualization. Further studies, including less experienced operators and external review of recorded ultrasound procedures, are necessary to confirm our findings. The main objective of the present study was to evaluate the clinical performance of the oblique approach to ultrasoundguided IJVC. We found that OAX and SAX are better than LAX in terms of cannulation quality outcomes (number of needle passes), and that OAX and LAX are better than SAX in terms of incidence of PVWP. We consider that OAX is a safe and effective approach to performing and teaching IJVC and that its use should be encouraged. Further clinical studies are needed to confirm this conclusion. Authors contributions Study design/planning: M.B., J.P., L.L., K.C., B.I. Study conduct: M.B., M.U., E.U., C.R. Data analysis: M.B., K.C., B.I. Writing paper: M.B. Revising paper: all authors Acknowledgements This study was led by M. Batllori, anaesthetist and medical PhD student at the Universidad de Navarra, Spain. The authors would like to thank Dr T. Belzunegui (Emergency Department, Complejo Hospitalario de Navarra) who served as scientific advisor and critically reviewed the initial study proposal, and Dr S. Cordón (Intensive Care Unit, Complejo Hospitalario de Navarra) who collected data regarding catheter-related blood stream infections in our study. We would also like to thank Dr M. Martín (head of Anaesthesiology Department at Complejo Hospitalario de Navarra Section A) for her important assistance and support during the recruitment phase. Declaration of interest None declared. Funding This work was supported by Instituto de Salud Carlos III, the main public investigation institution in Spain, which awarded the study with a FIS grant for health sciences investigation [grant number PI12/00679]. The funding was directed towards statistical analyses and communication of study results. All other study aspects were entirely supported by departmental resources. References 1. Troianos CA, Hartman GS, Glas KE, et al. SpecialArticles: Guidelines for Performing Ultrasound Guided Vascular Cannulation: Recommendations of the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. Anesth Analg 2012; 114: Lamperti M, Bodenham AR, Pittiruti M, et al. International evidence-based recommendations on ultrasound-guided vascular access. Intensive Care Med 2012; 38: Shekelle PG, Wachter RM, Pronovost PJ, et al. Making health care safer II: an updated critical analysis of the evidence for patient safety practices. Evid Rep Technol Assess (Full Rep) 2013; 211: 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: R Milling TJ Jr, Rose J, Briggs WM, et al. Randomized, controlled clinical trial of point-of-care limited ultrasonography assistance of central venous cannulation: the Third Sonography Outcomes Assessment Program (SOAP-3) Trial. Crit Care Med 2005; 33: Phelan M, Hagerty D. The oblique view: an alternative approach for ultrasound-guided central line placement. J Emerg Med 2009; 37: Dilisio R, Mittnacht AJ. The medial-oblique approach to ultrasound-guided central venous cannulation maximize

7 376 Batllori et al. the view, minimize the risk. J Cardiothorac Vasc Anesth 2012; 26: Ho AM-H, Ricci CJ, Ng CS, et al. The medial-transverse approach for internal jugular vein cannulation: an example of lateral thinking. J Emerg Med 2012; 42: French J, Raine-Fenning N, Hardman J, Bedforth N. Pitfalls of ultrasound guided vascular access: the use of three/four-dimensional ultrasound. Anaesthesia 2008; 63: Blaivas M, Adhikari S. An unseen danger: Frequency of posterior vessel wall penetration by needles during attempts to place internal jugular vein central catheters using ultrasound guidance. Crit Care Med 2009; 37: Milling T, Holden C, Melniker L, Briggs WM, Birkhahn R, Gaeta T. Randomized Controlled Trial of Single-Operator vs. Two-Operator Ultrasound Guidance for Internal Jugular Central Venous Cannulation. Acad Emerg Med 2006; 13: Chittoodan S, Breen D, O Donnell BD, Iohom G. Long versus short axis ultrasound guided approach for internal jugular vein cannulation: a prospective randomised controlled trial. Med Ultrason 2011; 13: Tammam TF, El-Shafey EM, Tammam HF. Ultrasound-guided internal jugular vein access: comparison between short axis and long axis techniques. Saudi J Kidney Dis Transplant 2013; 24: Ball R, Scouras N, Orebaugh S, Wilde J, Sakai T. Randomized, prospective, observational simulation study comparing residents needle-guided vs free-hand ultrasound techniques for central venous catheter access. Br J Anaesth 2012; 108: Stone MB, Moon C, Sutijono D, Blaivas M. Needle tip visualization during ultrasound-guided vascular access: shortaxis vs long-axis approach. Am J Emerg Med 2010; 28: Moak JH, Lyons MS, Wright SW, Lindsell CJ. Needle and guidewire visualization in ultrasound-guided internal jugular vein cannulation. Am J Emerg Med 2011; 29: Vogel JA, Haukoos JS, Erickson CL, et al. Is long-axis view superior to short-axis view in ultrasound-guided central venous catheterization? Crit Care Med 2015; 43: Leung J, Duffy M, Finckh A. Real-time ultrasonographicallyguided internal jugular vein catheterization in the emergency department increases success rates and reduces complications: a randomized, prospective study. Ann Emerg Med. 2006; 48: Moon CH, Blehar D, Shear MA, et al. Incidence of Posterior Vessel Wall Puncture During Ultrasound-guided Vessel Cannulation in a Simulated Model. Acad Emerg Med 2010; 17: Blaivas M. A rare look at a cause for vascular access failure after correct needle placement under ultrasound guidance. J Ultrasound Med 2008; 27: Wilson JG, Berona KM, Stein JC, Wang R. Oblique-axis vs. Short-axis View in Ultrasound-guided Central Venous Catheterization. J Emerg Med 2014; 47: Handling editor: J. P. Thompson