Low Posterior Internal Jugular Vein Approach for Tunnelled Haemodialysis Catheter Insertion: A Report on Outcomes at a Single Centre

AIM

The impact of technical differences in cannulation technique for tunnelled haemodialysis catheter insertion is undetermined. We aimed to assess clinical outcomes of the low posterior approach for internal jugular vein tunnelled catheter placement.

METHODS

A retrospective audit was undertaken on consecutive tunnelled catheter procedures performed at a single centre between January 2016 and June 2022. Only catheters specifically placed with a low posterior internal jugular approach were included. The study's primary outcome was 12-month catheter survival, evaluated using the Kaplan-Meier survival curve and log-rank test. Secondary outcomes included catheter performance and procedure-related complications.

RESULTS

During the study period, 391 tunnelled internal jugular haemodialysis catheters were inserted in 272 patients using the low posterior technique. The 12-month primary patency rate was 68%. Catheter insertion was successful in 96% of cases. Peri-procedural complications occurred in 4% of cases, most frequently bleeding. The most common reasons for catheter loss were dysfunction (10%) and bacteraemia (6%). The best predictors of catheter failure were advanced age (HR 1.02, 95% CI 1.00-1.04) and in-centre dialysis treatment locality (HR 2.04, 95% CI 1.19-3.45).

CONCLUSION

The low posterior approach for internal jugular vein tunnelled catheter insertion is effective and safe. We demonstrated a 12-month catheter survival rate of 68%. Further research comparing the low posterior approach with other internal jugular vein cannulation techniques is warranted.

Modified combined short and long axis method versus oblique axis method in adult patients undergoing right internal jugular vein cannulation: A randomized controlled non-inferiority study

BACKGROUND

Modified combined short and long axis method (MCSL) can replace oblique axis in-plane method (OA-IP) for internal jugular vein cannulation (IJVC). This randomized, non-inferiority study estimated the efficacy of MCSL compared with OA-IP in right IJVC.

METHODS

Patients (18-75 yr. old) undergoing right IJVC under local anesthesia were randomly assigned to MCSL or OA-IP group. The primary outcome is the event of first needle pass without posterior vessel wall puncture (PVWP). Secondary outcomes included needle attempts, success rate, puncture and cannulation time, needle visualization, probe placement difficulty and complications.

RESULTS

Among 190 randomized patients, 187 were involved in the analysis. The first needle pass without PVWP was 85(89.47%) in the MCSL and 81 (85.26%) in the OA-IP (p = 0.382), with a mean rate difference of 4.2% (95% confidence interval: -5.2-13.6), which confirmed the non-inferiority with the margin of -8%. MCSL group exhibited shorter procedure time and lower complications than OA-IP group. No significant differences were discovered between groups in needle attempts, success rate, incidence of probe placement difficulty and needle visualization.

CONCLUSIONS

MCSL is non-inferior to OA-IP in first needle pass without PVWP in adults who underwent elective right IJVC and associate with less complications and shorter operating time.

CLINICAL TRIAL REGISTRATION

ChiCTR, ChiCTR2100046899.

Role of point-of-care ultrasound in critical care and emergency medicine: update and future perspective

Point-of-care ultrasound (POCUS) is a rapidly developing technology that has the potential to revolutionize emergency and critical care medicine. The use of POCUS can improve patient care by providing real-time clinical information. However, appropriate usage and proper training are crucial to ensure patient safety and reliability. This article discusses the various applications of POCUS in emergency and critical care medicine, the importance of training and education, and the future of POCUS in medicine.

Short-axis versus long-axis approach for ultrasound-guided vascular access: An updated systematic review and meta-analysis of randomised controlled trials

Background and Aims

There are two approaches for ultrasound (US)-guided vessel cannulation: the short axis (SA) approach and the long axis (LA) approach. However, it remains to be seen which approach is better. Therefore, we performed the present updated systematic review and meta-analysis to assess the effectiveness and safety of US-guided vascular cannulation between the SA and LA techniques.

Methods

We performed a comprehensive electronic database search in PubMed, Embase, Cochrane Library and Web of Science for the relevant studies from inception to June 2022. Randomised controlled trials comparing the SA approach and the LA approach for US-guided vascular access were incorporated in this updated meta-analysis. The first-attempt success rate was the primary outcome. The secondary outcomes were the overall success rate, cannulation time, number of attempts and the incidence of complications. The statistical analysis was conducted using RevMan software (version 5.4; the Nordic Cochrane Centre, the Cochrane Collaboration, Copenhagen, Denmark). The Cochrane risk of bias tool was used to evaluate each study's potential risk for bias.

Results

In total, 16 studies consisting of 1885 participants were incorporated in this updated meta-analysis. No statistically significant difference was found between the SA and LA vascular access techniques for first-pass success rate (risk ratio = 1.07, 95% confidence interval: 0.94-1.22). The overall cannulation success rate, complication rate, average cannulation time and average number of attempts were not significantly different between the SA and LA groups.

Conclusion

This updated meta-analysis demonstrated that the SA and LA approaches of US-guided vessel cannulation are similar regarding first-pass success, overall cannulation success rate, total complication rate, cannulation time and the number of attempts.

Single-plane versus real-time biplane approaches for ultrasound-guided central venous catheterization in critical care patients: a randomized controlled trial

BACKGROUND

Critical care patients often require central venous cannulation (CVC). We hypothesized that real-time biplane ultrasound-guided CVC would improve first-puncture success rate and reduce mechanical complications. The purpose of this study was to compare the success rate and safety of single-plane and real-time biplane approaches for ultrasound-guided CVC.

METHODS

From October 2022 to March 2023, 256 participants with critical illness requiring CVC were randomized to either the single-plane (n = 128) or biplane (n = 128) ultrasound-guided cannulation groups. The success rate, number of punctures, procedure duration, incidence of catheterization-related complications, and confidence score of operators were documented.

RESULTS

The central vein was successfully cannulated in all 256 participants (163 [64%] man and 93 [36%] women; mean age 69 ± 19 [range 13-104 years]), including 182 and 74 who underwent internal jugular vein cannulation (IJVC) and femoral vein cannulation (FVC), respectively. The incidence of successful puncture on the first attempt was higher in the biplane group than that in the single-plane group (91.6% vs. 74.7%; relative risk (RR), 1.226; 95% confidence interval (CI), 1.069-1.405; P = 0.002 for the IJVC and 90.9% vs. 68.3%; RR, 1.331; 95% CI, 1.053-1.684; P = 0.019 for the FVC). The biplane group was also associated with a higher first-puncture single-pass catheterization success rate (87.4% vs. 69.0% and 90.9% vs. 68.3%), fewer undesired punctures (1[1-1(1-2)] vs. 1[1-2(1-4)] and 1[1-1(1-3)] vs. 1[1-2(1-4)]), shorter cannulation time (205 s [162-283 (66-1,526)] vs. 311 s [243-401 (136-1,223)] and 228 s [193-306 (66-1,669)] vs. 340 s [246-499 (130-944)]), and fewer immediate complications (10.5% vs. 28.7% and 9.1% vs. 34.1%) for both IJVC and FVC (all P < 0.05).

CONCLUSION

Real-time biplane imaging of ultrasound-guided CVCs offers advantages over the single-plane approach for critically ill patients.

TRIAL REGISTRATION

This prospective RCT was registered at Chinese Clinical Trial Registry (ChiCTR2200064843). Registered 19 October 2022.

Comparison of ultrasound-guided internal jugular vein and supraclavicular subclavian vein catheterization in critically ill patients: a prospective, randomized clinical trial

Background

The aim of this study was to compare the effectiveness and safety of ultrasound-guided out-of-plane internal jugular vein (OOP-IJV) and in-plane supraclavicular subclavian vein (IP-SSCV) catheterization in adult intensive care unit.

Methods

A total of 250 consecutive patients requiring central venous catheterization, were randomly assigned to undergo either ultrasound-guided OOP-IJV or IP-SSCV cannulation. All catheterizations were carried out by three physicians. The primary outcome was the first attempt success rate. Ultrasound scanning time, venous puncture time, insertion time, overall access time, number of puncture attempts, number of needle redirections, success rate, guidewire advancing difficulties, venous collapse and adverse events were also documented.

Results

The first attempt success rate was significantly higher in IP-SSCV group (83.2%) compared to OOP-IJV group (63.2%) (p = 0.001). The IP-SSCV group was associated with a longer ultrasound scanning time (16.54 ± 13.51 vs. 5.26 ± 4.05 s; p < 0.001) and a shorter insertion time (43.98 ± 26.77 vs. 53.12 ± 40.21 s; p = 0.038). In the IP-SCCV group, we recorded a fewer number of puncture attempts (1.16 ± 0.39 vs. 1.47 ± 0.71; p < 0.001), needle redirections (0.69 ± 0.58 vs. 1.17 ± 0.95; p < 0.001), difficulties in guidewire advancement (2.4% vs. 27.4%; p < 0.001), venous collapse (2.4%, vs. 18.4%; p < 0.001) and adverse events (8.8% vs. 13.6%; p = 0.22).

Conclusions

The IP-SSCV approach is an effective and a safe alternative to the classic OOP-IJV catheterization in critical adult patients.

Trial registration: Clinicaltrials.gov, NCT03879954. Registered March 19, 2019—Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03879954.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01065-x.

Compare the Efficacy and Safety of Modified Combined Short and Long Axis Method versus Oblique Axis Method for Right Internal Jugular Vein Catheterization in Adult Patients (The MCSLOA Trial): Study Protocol of a Randomized Controlled Trial

Background

Ultrasound-guided internal jugular vein (IJV) catheterization has become a standard procedure as it yields a higher success rate and fewer mechanical complications compared with an anatomical landmark technique. There are several common methods for ultrasound guidance IJV catheterization, such as short-axis out-of-plane, long-axis in-plane and oblique axis in-plane, but these technologies are still developing. It is important to further study the application of different ultrasound-guided IJV puncture techniques and find an effective and safe ultrasound-guided puncture technique.

Methods

A China randomized, open-label, parallel, single center, positive-controlled, non-inferiority clinical trial will evaluate 190 adult patients undergoing elective surgery and need right jugular vein catheterization. Study participants randomized in a 1:1 ratio into control and experimental groups. The control group will take the oblique axis in-plane method for IJV catheterization. The experimental group will take the Modified combined short and long axis method. The primary endpoint of the trial is the rate of one-time successful guidewire insertion without posterior wall puncture (PWP). Secondary endpoints are the number of needle insertion attempts, the total success rate, the procedure time, and mechanical complications.

Conclusion

This randomized controlled trial will evaluate the effectiveness and safety of Modified combined short and long axis method and oblique axis in-plane method for right IJV catheterization in adult patients.

Comparison of ultrasound-guided internal jugular vein cannulation versus supraclavicular approach to brachiocephalic vein cannulation– A prospective, single-blind, randomised study

Background and Aims:

The internal jugular vein (IJV) is the most common site for central venous cannulation. Ultrasonography (USG)-guided brachiocephalic vein (BCV) cannulation has been described recently. The objective of this study was to compare the first attempt success rate, overall success rate and procedural ease between two techniques.

Methods:

This was a prospective, single-blinded, randomised clinical study. Patients were randomly allocated into two groups using computer generated random table. Group IJV included 55 patients of USG-guided out-of-plane approach to the right IJV cannulation and group BCV included 55 patients for USG-guided supraclavicular in-plane approach to right BCV cannulation. The success rate, number of redirections needed, vein and needle tip visualisation, cannulation time and complication rate were compared between the groups.

Results:

Demographic parameters were similar between the groups. Success rate of cannulation was 98.5% in IJV group and 100% in group BCV (P = 0.31). The first attempt success rate was 76.3% and 81.81% in IJV and BCV group, respectively (P = 0.42). IJV was collapsed in 14.5% cases and BCV was collapsed in 0.9% cases. The needle visualisation was better in BCV group (94.54%) compared to IJV (80%) (P = 0.02) group, which was statistically significant. The numbers of redirections of needle were more in IJV group. Thus the procedural ease was better with BCV than IJV.

Conclusion:

Supraclavicular USG-guided in-plane BCV cannulation is a good alternative to USG-guided out-of-plane IJV cannulation, because of good calibre of the vein and better needle visualisation in the BCV group.

Modified Long-Axis In-Plane Ultrasound-guided Radial Artery Cannulation In Adult Patients: A Randomized Controlled Trial

INTRODUCTION

For adults with small radial arteries, ultrasound-guided radial artery cannulation remains challenging and the relevant data is currently lacking. The study aimed to test the hypothesis that modified long-axis in-plane ultrasound guidance (M-LAIP) would improve success rates of radial artery cannulation in this population.

PATIENTS AND METHODS

This was a prospective, randomised, and controlled clinical study that enrolled 201 adult patients with diameters of the radial artery less than 2.2 mm. Patients were randomised to M-LAIP, short-axis out-of-plane (SAOP), or conventional palpation (C-P) group according to different approaches of radial artery cannulation (M-LAIP, SAOP, and C-P). Outcome measurements included the success rate, cannulation time, and cannulation-related adverse events.

RESULTS

The cannulation success rate was significantly higher in the M-LAIP group than in the SAOP or C-P groups (first success rate: 80.3% vs. 53.8% or 33.8%; P < 0.001; total success rate: 93.9% vs. 78.5% or 50.8%; P < 0.001). Total cannulation time in the M-LAIP group was shorter than that in the SAOP group (P =  0.002) or the C-P group (P < 0.001). The rates of posterior wall puncture and haematoma in the M-LAIP group were lower than that in the SAOP group or C-P group (P <  0.008).

CONCLUSION

The use of the M-LAIP approach significantly improved the success rate of radial artery cannulation, shortened procedure time, and lowered the rates of posterior wall puncture and haematoma in adults with radial artery diameters less than 2.2 mm, compared with that achieved by the SAOP or C-P approach.

Comparison of Three Ultrasound Views for Internal Jugular Venous Cannulation in Patients Undergoing Cardiac Surgery: A Randomized Trial

Background:

The quality of needle visualization during ultrasound-guided internal jugular vein (IJV) cannulation determines the ease of procedure, whereas posterior IJV wall puncture is the most common risk associated. The IJV can be imaged in different views, which offer certain advantages over each other. We compared three different ultrasound views for IJV cannulation short axis (SAX), long axis (LAX), and oblique axis (OAX) with respect to the quality of needle visualization, first pass success rate, and posterior IJV wall puncture.

Methods:

Two hundred ten patients undergoing elective cardiac surgery were analyzed in this prospective randomized clinical trial. Patients were randomly assigned to one of the three groups: SAX (n = 70), LAX (n = 70), and OAX (n = 70). The quality of needle visualization, first pass success rate, and incidence of posterior IJV wall puncture in each of the three ultrasound views were studied. The Chi-square test and ANOVA were used for the comparison of means and proportion between the groups.

Results:

The quality of needle visualization was graded as good in 90% patients in OAX group, 81.4% patients in LAX group, and 14.2% patients in SAX group, respectively (P < 0.0001). OAX group had the highest first pass success rate (94.2%) followed by SAX (88.5%), and then, LAX (82.8%), but it was statistically insignificant among the groups (P = 0.105). The mean IJV access time was longer in LAX group when compared to OAX and SAX group (P < 0.0001).The incidence of IJV posterior wall puncture was 14.2% patients in SAX group and none in other groups (P = 0.0011).

Conclusion:

The results suggest that OAX view can be adopted as standard approach during ultrasound-guided IJV cannulation as it safe and reliable.

Real-time ultrasound-guided internal jugular vein cannulation by oblique-axis in-plane: Practice at the Fourth Hospital of Hebei Medical University

OBJECTIVE

We aimed to evaluate oblique-axis in-plane (OA-IP) techniques for real-time ultrasound-guided internal jugular vein (IJV) cannulation.

METHODS

We retrospectively analysed 1065 patients who underwent ultrasound (US)-guided IJV cannulation. We recorded demographic characteristics of patients, success rate, access time, cannulation time, number of attempts and the incidence of acute complications.

RESULTS

The overall success rate of the procedure was 100% (n = 1605). In total, 1594 cases (99.3%) were successful at the first attempt, and 11 (0.7%) were successful at the second attempt; no patient required three or more attempts. The mean access time was 18.7 ± 19.3 seconds. The mean cannulation time was 349.0 ± 103.8 seconds. There were 54 (3.4%) acute complications out of the total 1605 cannulations: 23 cases of puncture site bleeding (1.4%), 20 cases allergic to dressing (1.3%), 10 cases of local cervical hematomas (0.6%), and one catheter misplacement (0.1%). There were no major complications 12 hours following the procedure.

CONCLUSIONS

The results of our study suggest that OA-IP techniques can improve ultrasound-guided IJV cannulation with a high success rate and safety in clinical practice. Clinicians should consider adopting these methods.

Comparison of dynamic needle tip positioning versus conventional long-axis in-plane techniques for ultrasound-guided internal jugular venous catheterization: a randomized controlled trial

BACKGROUND

Continuous visualization of the needle tip is essential for successful ultrasound-guided central venous catheterization, and the dynamic needle tip positioning (DNTP) technique enables it. The aim of this randomized, dual-center trial was to compare the first-attempt success rate of ultrasound-guided internal jugular catheterization between the DNTP and conventional long-axis in-plane (LAX-IP) techniques.

METHODS

Patients undergoing cardiac surgery at two tertiary teaching hospitals were randomly allocated to either the DNTP or LAX-IP group. Internal jugular venous catheterization was performed by four anesthesiologists. The primary outcome was the first-attempt success rate of central venous catheterization. Procedural time and complications related to catheterization were compared as secondary outcomes.

RESULTS

In total, 142 patients were analysed. The first-attempt success rate was significantly higher in the DNTP group (59/72, 81.9%) than in the LAX-IP group (46/70, 65.7%; odds ratio, 2.37; 95% confidence interval 1.09-5.15; P=0.028). In addition, the needle was redirected less frequently in the DNTP group than the LAX-IP group (P=0.026). Procedural time was comparable between the groups. No significant differences were observed in complications related to catheterization, including posterior wall puncture, carotid artery puncture, or hematoma.

CONCLUSIONS

The DNTP technique resulted in a significantly higher success rate on the first attempt at internal jugular venous catheterization and required less frequent redirection of the needle during the procedure than the conventional LAX-IP technique.

Ultrasound-guided left internal jugular vein cannulation: Advantages of a lateral oblique axis approach

INTRODUCTION

Retrospective observational study to evaluate the technique of cannulation guided by ultrasound of the left internal jugular vein (LIJV) using a lateral oblique axis (LOAX) approach with variable angulation in the placement of tunneled central venous catheters (CVC) for hemodialysis.

METHODS

Seventy-one patients with 77 LIJV vascular accesses aged 16 or older who needed CVC for hemodialysis were evaluated. The catheters were inserted, guided by LOAX ultrasound with variable angulation, depending on the angulation of the left brachiocephalic trunk. The success rate, additional instrumentation needs, and number of immediate and late complications were analyzed.

FINDINGS

Central venous catheters placement was possible in all cases and none of the peelable introducers folded. A placement guide was needed in only eight patients, whose brachiocephalic trunk elongation and angulation was 90°. We found no major complications, and only five cases of minor complications (6.5%): four periprocedural and one displacement of the catheter a week after placement.

DISCUSSION

Tunneled CVC percutaneous cannulation in LIJV guided by ultrasound with the LOAX approach with variable angulation provides very good results, allows visualization of the needle and the vascular structures at the same time, and reduces the number of manoeuvers required for placement and complications that might arise.

Internal Jugular Vein Cannulation Using a 3-Dimensional Ultrasound Probe in Patients Undergoing Cardiac Surgery: Comparison Between Biplane View and Short-Axis View

OBJECTIVE

To compare the clinical performance in terms of procedure time, success rate, and cannulation attempts between ultrasound biplane view (BPX) and short-axis (SAX) view for internal jugular vein cannulation (IJV) in patients undergoing cardiac surgery.

DESIGN

Prospective, observational pilot study.

SETTING

University level tertiary referral hospital.

PATIENTS

The study comprised 100 patients between ages 18 and 75 years undergoing elective cardiac surgery.

INTERVENTIONS

One hundred patients were divided into 2 groups of 50 (BPX group and SAX group) by assigning the study participants alternatively to each group. IJV cannulation was performed using a 3-dimensional ultrasound probe in all patients with either BPX view (BPX group, n = 50) or the SAX view (SAX group, n = 50) by an experienced anesthesiologist.

MEASUREMENTS AND MAIN RESULTS

Time required for imaging, time for IJV puncture, time for guidewire confirmation, number of needle punctures and needle redirections, and incidence of posterior wall puncture were noted in both groups. In addition, the quality of needle visualization and the incidence of complications were recorded. The time taken for imaging was significantly greater in the BPX group than in the SAX group (9.52 ± 2.69 s v 7.94 ± 2.55 s; p = 0.0034), whereas the time taken for IJV puncture (10.39 ± 2.33 s v 23.7 ± 2.46 s; p < 0.0001), time taken for confirmation of guidewire (32.94 ± 4.50 s v 57.64 ± 7.14 s; p < 0.0001), and the incidence of posterior wall puncture (4% v 26%; p = 0.0022) were significantly less in the BPX group than in the SAX group. The total number of attempts taken to puncture the IJV was fewer in the BPX group than in the SAX group (55 v 78). Successful puncture of the IJV occurred on the first attempt in 90% of patients in the BPX group, whereas it was only 50% in the SAX group (p < 0.0001). The quality of needle visualization was good in 90% of patients in the BPX group, whereas it was only 6% in the SAX group. The number of needle redirections for IJV puncture was less in the BPX group than in the SAX group (48 v 116). The incidence of complications was not significant between the 2 groups.

CONCLUSION

The results suggested that the BPX view may be a safer, feasible and more reliable method than the SAX view for IJV cannulation in cardiac surgical patients.

[Short-axis versus long-axis approach in ultrasound-guided central venous cannulation: an updated systematic review and meta-analysis]

OBJECTIVE

To compare the success rate and safety of the short-axis (SAX) approach and long- axis (LAX) approach to ultrasound-guided central venous cannulation.

METHODS

Electronic bibliographic databases including PubMed, Cochrane Library, Science Direct, and Web of Science were searched for randomized controlled trials comparing ultrasound-guided central venous cannulation via the LAX and SAX approaches published during the period from January, 2011 to October, 2017. We extracted the data from the eligible studies and assessed the first-attempt success rate, overall puncture success rate and complication rate of the two approaches. The relative risk (RR) with the 95% CI was calculated using a fixed or random effects model.

RESULTS

Seven randomized controlled trials were included for meta-analysis. The results showed that the first-attempt success rate was significantly higher in the SAX group than in the LAX group (RR=1.27, 95%CI: 1.11-1.46; P=0.0005, I²=49%), but the overall puncture success rate did not differ significantly between the two approaches (RR=1.04, 95%CI: 0.97-1.10; P=0.27, I²=84%). The incidence of accidental arterial puncture with the SAX approach was significantly lower than that with the LAX approach (RR=1.04; 95%CI: 1.01-1.08; P=0.01, I²=30%).

CONCLUSIONS

Ultrasound-guided central venous cannulation via the SAX approach, as compared with the LAX approach, can increase first-attempt success rate and reduce the incidence of accidental arterial puncture.

Does longitudinal or transverse orientation of the ultrasound probe improve cannulation success in minimally invasive venous surgery: A multicentre randomised controlled trial

OBJECTIVE

This study evaluates the effect of transverse and longitudinal ultrasound transducer orientation on saphenous vein cannulation during endovenous ablation.

METHODS

A single-blinded, multicentre, randomised controlled trial was performed in patients undergoing ultrasound-guided venous cannulation for saphenous ablation. The primary outcomes were overall cannulation success and time to successful cannulation.

RESULTS

In total, 100 patients were assigned to parallel longitudinal orientation and transverse orientation groups. Cannulation success was 100%. There was no significant variation in time to cannulation detected between the transverse orientation and longitudinal orientation (85 s vs. 71 s, p = 0.314). Longitudinal orientation was associated with significantly fewer needle passes [median 3 (interquartile range 1-5) vs. 2 (interquartile range 1-3), p = 0.026] and less pain (median visual analogue scale score 1 vs. 2.5, p = 0.039) than those in the transverse orientation group.

CONCLUSION

This trial has shown that while longitudinal orientation is associated with less procedural pain it has no significant effect on time to target vein cannulation during endovenous ablation.

Lateral oblique approach for internal jugular vein catheterization: Randomized comparison of oblique and short-axis view of ultrasound-guided technique

OBJECTIVE:

The lateral oblique approach is a novel needle-in-plane technique for ultrasound-guided catheterization of the internal jugular vein. In this study, we aimed to compare the oblique approach with the classical short-axis technique for facilitating the procedure and reduction of mechanical complications.

METHODS:

This research was planned as a prospective study. Eighty-four open-heart surgery patients requiring a central venous catheter were randomly allocated into two groups: Oblique approach group (n=42) and short-axis group (n=42). Time to cannulate, the number of necessary puncture attempts, and frequency of carotid artery puncture, hematoma, puncture site bleeding, pneumothorax, and hemothorax in each group were recorded. Visualization of the vein and the needle using ultrasound were also evaluated by a subjective scale.

RESULTS:

The patient’s characteristics were comparable between the two groups. The mean time of catheterization was 52.00±70.18 seconds in the oblique approach group and 40.76±49.30 seconds in short-axis group. The mean number of needle puncture attempts was 1.21±0.61 in oblique approach and 1.12±0.50 in short-axis group. The results did not differ significantly. There was an improved visualization of the needle in the oblique approach group, but this was not proved as statistically significant.

CONCLUSION:

The results of our study suggest that the lateral oblique approach is a safe and effective technique, which can be a strong alternative to the classical short-axis technique for ultrasound-guided catheterization of the internal jugular vein.

A prospective, randomised, comparative study to evaluate long axis, short axis and medial oblique axis approach for ultrasound-guided internal jugular vein cannulation

Background and Aims:

The Ultrasound (USG)-guided internal jugular vein (IJV) cannulation can be performed using different approaches like short axis (SAX), long axis (LAX), oblique axis (OAX) or medial oblique axis (M-OAX). We aimed to determine which view was optimal for IJV cannulation.

Methods:

After ethical committee approval and written informed consent, this prospective, randomised, controlled trial was conducted on 108 patients. Patients were allocated into one of the three groups: A (SAX), B (LAX) and C (M-OAX approach) for USG-guided IJV cannulation. The number of needle passes, the success of IJV cannulation and its diameter, venous access time, guidewire time, catheterisation time and complications if any were recorded. Statistical analysis was performed by SPSS version 17.0.

Results:

First needle pass success rate was highest in M-OAX (97.2%) followed by SAX (88.9%) and then LAX (77.8%) but it was statistically insignificant among the groups. Mean venous access, guidewire insertion and catheterisation time were shortest in M-OAX followed by SAX and then LAX approach. It was statistically significant between LAX and SAX and between LAX and M-OAX group. (P < 0.001). The carotid puncture was noticed in two patients in the LAX group. The overall success rate and the number of needle passes were comparable among the groups.

Conclusion:

The M-OAX approach is a safe and effective technique for USG-guided IJV cannulation when compared to SAX and LAX approaches.

Recommendations on the Use of Ultrasound Guidance for Central and Peripheral Vascular Access in Adults: A Position Statement of the Society of Hospital Medicine

PREPROCEDURE

1)We recommend that providers should be familiar with the operation of their specific ultrasound machine prior to initiation of a vascular access procedure. 2)We recommend that providers should use a high-frequency linear transducer with a sterile sheath and sterile gel to perform vascular access procedures. 3)We recommend that providers should use two-dimensional ultrasound to evaluate for anatomical variations and absence of vascular thrombosis during preprocedural site selection. 4)We recommend that providers should evaluate the target blood vessel size and depth during preprocedural ultrasound evaluation.

TECHNIQUES

General Techniques 5) We recommend that providers should avoid using static ultrasound alone to mark the needle insertion site for vascular access procedures. 6)We recommend that providers should use real-time (dynamic), two-dimensional ultrasound guidance with a high-frequency linear transducer for central venous catheter (CVC) insertion, regardless of the provider's level of experience. 7)We suggest using either a transverse (short-axis) or longitudinal (long-axis) approach when performing real-time ultrasound-guided vascular access procedures. 8)We recommend that providers should visualize the needle tip and guidewire in the target vein prior to vessel dilatation. 9)To increase the success rate of ultrasound-guided vascular access procedures, we recommend that providers should utilize echogenic needles, plastic needle guides, and/or ultrasound beam steering when available. Central Venous Access Techniques 10) We recommend that providers should use a standardized procedure checklist that includes the use of real-time ultrasound guidance to reduce the risk of central line-associated bloodstream infection (CLABSI) from CVC insertion. 11)We recommend that providers should use real-time ultrasound guidance, combined with aseptic technique and maximal sterile barrier precautions, to reduce the incidence of infectious complications from CVC insertion. 12)We recommend that providers should use real-time ultrasound guidance for internal jugular vein catheterization, which reduces the risk of mechanical and infectious complications, the number of needle passes, and time to cannulation and increases overall procedure success rates. 13)We recommend that providers who routinely insert subclavian vein CVCs should use real-time ultrasound guidance, which has been shown to reduce the risk of mechanical complications and number of needle passes and increase overall procedure success rates compared with landmark-based techniques. 14)We recommend that providers should use real-time ultrasound guidance for femoral venous access, which has been shown to reduce the risk of arterial punctures and total procedure time and increase overall procedure success rates. Peripheral Venous Access Techniques 15) We recommend that providers should use real-time ultrasound guidance for the insertion of peripherally inserted central catheters (PICCs), which is associated with higher procedure success rates and may be more cost effective compared with landmark-based techniques. 16)We recommend that providers should use real-time ultrasound guidance for the placement of peripheral intravenous lines (PIV) in patients with difficult peripheral venous access to reduce the total procedure time, needle insertion attempts, and needle redirections. Ultrasound-guided PIV insertion is also an effective alternative to CVC insertion in patients with difficult venous access. 17)We suggest using real-time ultrasound guidance to reduce the risk of vascular, infectious, and neurological complications during PIV insertion, particularly in patients with difficult venous access. Arterial Access Techniques 18)We recommend that providers should use real-time ultrasound guidance for arterial access, which has been shown to increase first-pass success rates, reduce the time to cannulation, and reduce the risk of hematoma development compared with landmark-based techniques. 19)We recommend that providers should use real-time ultrasound guidance for femoral arterial access, which has been shown to increase first-pass success rates and reduce the risk of vascular complications. 20)We recommend that providers should use real-time ultrasound guidance for radial arterial access, which has been shown to increase first-pass success rates, reduce the time to successful cannulation, and reduce the risk of complications compared with landmark-based techniques.

POSTPROCEDURE

21) We recommend that post-procedure pneumothorax should be ruled out by the detection of bilateral lung sliding using a high-frequency linear transducer before and after insertion of internal jugular and subclavian vein CVCs. 22)We recommend that providers should use ultrasound with rapid infusion of agitated saline to visualize a right atrial swirl sign (RASS) for detecting catheter tip misplacement during CVC insertion. The use of RASS to detect the catheter tip may be considered an advanced skill that requires specific training and expertise.

TRAINING

23) To reduce the risk of mechanical and infectious complications, we recommend that novice providers should complete a systematic training program that includes a combination of simulation-based practice, supervised insertion on patients, and evaluation by an expert operator before attempting ultrasound-guided CVC insertion independently on patients. 24)We recommend that cognitive training in ultrasound-guided CVC insertion should include basic anatomy, ultrasound physics, ultrasound machine knobology, fundamentals of image acquisition and interpretation, detection and management of procedural complications, infection prevention strategies, and pathways to attain competency. 25)We recommend that trainees should demonstrate minimal competence before placing ultrasound-guided CVCs independently. A minimum number of CVC insertions may inform this determination, but a proctored assessment of competence is most important. 26)We recommend that didactic and hands-on training for trainees should coincide with anticipated times of increased performance of vascular access procedures. Refresher training sessions should be offered periodically. 27)We recommend that competency assessments should include formal evaluation of knowledge and technical skills using standardized assessment tools. 28)We recommend that competency assessments should evaluate for proficiency in the following knowledge and skills of CVC insertion: (a) Knowledge of the target vein anatomy, proper vessel identification, and recognition of anatomical variants; (b) Demonstration of CVC insertion with no technical errors based on a procedural checklist; (c) Recognition and management of acute complications, including emergency management of life-threatening complications; (d) Real-time needle tip tracking with ultrasound and cannulation on the first attempt in at least five consecutive simulation. 29)We recommend a periodic proficiency assessment of all operators should be conducted to ensure maintenance of competency.

Comparison of short and long axis ultrasound-guided approaches to internal jugular vein puncture: a meta-analysis

Objective

To compare short-axis versus long-axis plane for ultrasound-guided internal jugular vein puncture.

Methods

PubMed, Embase, Cochrane Library and CNKI databases were searched for randomized controlled trials, published to 1 June 2019, that compared short- versus long-axis plane in ultrasound-guided internal jugular vein puncture. Statistical analyses were performed using RevMan software, version 5.3. Statistical results are presented as risk ratio (RR) (95% confidence interval [CI]) for dichotomous data and standard mean difference (SMD) (95% CI) for continuous data.

Results

Ten studies fulfilled the inclusion criteria. Analyses of pooled results showed no statistically significant differences in arterial puncture incidence between the two planes (RR 0.73 [95% CI 0.38, 1.39]). First-pass success rate (RR 1.08 [95% CI 0.95, 1.22]), total success rate (RR 1.00 [95% CI 0.99, 1.02]) and number of attempts required (SMD –0.09 [95% CI –0.37, 0.18]) were also similar between the two approaches. Trial sequential analysis indicated that the available evidence was insufficient to detect potential differences between the two techniques.

Conclusions

There is insufficient data for an evidence-based choice of either short- or long-axis plane in ultrasound-guided internal jugular vein puncture.

Comparison of long-, short-, and oblique-axis approaches for ultrasound-guided internal jugular vein cannulation: A network meta-analysis

BACKGROUND

Comparison between various approaches of ultrasound (USG)-guided internal jugular vein cannulation, that is, short-axis out-of-plane approach, long-axis in-plane approach, and oblique-axis approach, is sparse. In this network meta-analysis of randomized controlled trials, all three approaches were evaluated to identify the best technique for USG-guided internal jugular vein cannulation.

METHODS

Randomized controlled trials comparing short-axis out-of-plane approach, long-axis in-plane approach, and oblique-axis approach in any combination (i.e. comparison of any two or all three) for USG-guided internal jugular vein cannulation were included in this meta-analysis. Bayesian network meta-analysis was conducted with a non-informative prior effect size and heterogeneity, and all results were reported as posterior median odds ratio with 95% credible interval.

RESULTS

Data of 658 patients from five randomized controlled trials were included in this meta-analysis. No difference was obtained in first attempt success rate of cannulation in three approaches (posterior median odds ratio between long-axis and short-axis view, oblique-axis and short-axis view, and long-axis and oblique-axis view were 0.67 (0.20, 2.08), 0.92 (0.09, 4.790), and 1.3420 (0.1680, 6.7820), respectively). No difference was seen in the incidence of carotid artery puncture and overall success rate of cannulation.

CONCLUSION

All three commonly used approaches for USG-guided internal jugular vein cannulation, that is, short axis, long axis, and oblique axis, are comparable in terms of clinical utility and safety. There is insufficient evidence to recommend one approach over another for this purpose.

A modified approach for ultrasound-guided axillary venipuncture in the infraclavicular area: A retrospective observational study

BACKGROUND

Catheterization of the axillary vein in the infraclavicular area has important advantages in patients with long-term, indwelling central venous catheters. The two most commonly used ultrasound-guided approaches for catheterization of the axillary vein include the long-axis/in-plane approach and the short-axis/out-of-plane approach, but there are certain drawbacks to both approaches. We have modified a new approach for axillary vein catheterization: the oblique-axis/in-plane approach.

METHODS

This observational study retrospectively collected data from patients who underwent ultrasound-guided placement of an axillary vein infusion port in the infraclavicular area at the Central Venous Access Clinics of Zhongshan Hospital at Fudan University between March 2014 and May 2017. The patients' demographic data, success rate of catheterization, venous catheterization site, and immediate complications associated with catheterization were recorded.

RESULTS

Between March 2014 and May 2017, a total of 858 patients underwent placement of an axillary vein infusion port in the infraclavicular area at our center. The ultrasound-guided oblique-axis/in-plane approach was used for all patients, and the venipuncture success rate was 100%. Two cases of accidental arterial puncture and one case of local hematoma formation were reported, and no other complications, such as pneumothorax or nerve damage, were reported.

CONCLUSION

The ultrasound-guided oblique-axis/in-plane approach is a safe and reliable alternative to the routine ultrasound-guided approach for axillary venous catheterization.

Evaluating the Long-, Short-, and Oblique-Axis Approaches for Ultrasound-Guided Vascular Access Cannulation

BACKGROUND

Our goal was to conduct a network meta-analysis of randomized controlled trials to compare the effects of the long-axis (LAX), short-axis (SAX), and oblique-axis (OAX) ultrasound guidance approaches for vascular access cannulation.

METHODS

We searched 5 databases, including the Cochrane Central Register of Controlled Trials in the Cochrane Library, Embase, MEDLINE, CINAHL, and Web of Science. Seven randomized clinical trials assessing ultrasound guidance for vascular access cannulation via the LAX, SAX, or OAX approach were included. The primary end point was the first-pass success rate. Secondary end points included the mean time to success and average number of attempts until success. We used random-effects models to calculate weighted mean differences with 95% confidence intervals for continuous outcomes and relative risks with 95% confidence intervals for dichotomous outcomes.

RESULTS

There were no significant differences between the LAX, SAX, and OAX techniques with respect to the first-pass success rate, mean time to success, average number of attempts until success, or the incidence of hematoma.

CONCLUSION

There was insufficient evidence to definitively recommend the LAX, SAX, or OAX approach for patients undergoing ultrasound-guided vascular access cannulation.

Vascular access in children

Securing stable vascular access is an important clinical skill for the anaesthesiologist. Sick children, complex surgeries, chronic illnesses, multiple hospitalisations, and prolonged treatments can make vascular access challenging. A search was done in the English language literature using the keywords "paediatric," "vascular access," "venous access," and "techniques" or "complications" in Pubmed, Embase, and Google scholar databases. Articles were screened and appropriate content was included. Intraosseous access is a lifesaving technique that can be performed even in hypovolaemic patients rapidly. Transillumination and near-infrared light improve visualisation of superficial veins in difficult access. Ultrasonography has become the standard of care in selecting the vessel, size of catheter, guide placement, and prevent complications. Fluoroscopy is used during insertion of long-term vascular access devices. This article reviews the various routes of access, their indications, most appropriate site, securing techniques, advantages, disadvantages, and complications associated with vascular access in children.

Posterior Wall Punctures Between Long- and Short-Axis Techniques in a Phantom Intravenous Model

OBJECTIVES

To determine whether a long-axis, in-plane approach to ultrasound-guided vascular access produces fewer posterior wall punctures than a short-axis, out-of-plane approach when attempted by novices without prior ultrasound-guided procedural experience.

METHODS

Participants were randomized to perform either technique on a ballistic gel-based phantom in a randomized controlled trial. They were then crossed over to repeat the experiment using the alternative approach. The primary outcome was posterior wall puncture occurrences. Secondary outcomes included cannulation success, the time to cannulation, and provider preferences. These were formulated before data collection.

RESULTS

Forty participants completed the study. There were 6 posterior wall punctures in the short-axis, out-of-plane approach (15%) and 1 in the long-axis, in-plane approach (2.5%). A posterior wall puncture was less likely to occur when the long-axis approach was used (odds ratio, 0.15; 95% confidence interval, 0.02-0.91). There was no statistical difference in rates of successful cannulation and the time to cannulation. Eighty percent preferred the long-axis approach, whereas 85% stated that the long-axis approach provided better visualization of the needle tip throughout the procedure.

CONCLUSIONS

The long-axis, in-plane approach compared to the short-axis, out-of-plane approach for ultrasound-guided cannulation on a phantom resulted in fewer posterior wall punctures, better needle tip visibility, and higher preference among novices.

A Shallow Angle Short-Axis Out-of-Plane Approach Reduces the Rate of Posterior Wall Injuries in Central Venous Catheterization: A Simulation Study

The short-axis out-of-plane approach (SAX-OOP) is commonly used in ultrasound-guided internal jugular vein catheterization. However, this approach has a risk of posterior vein wall injuries. The authors hypothesized that a shallow angle of approach may reduce the rate of posterior wall injuries compared with the conventional steep angle approach. The present study aimed to evaluate whether a difference in the angle of approach of the needle affects the rate of posterior wall injuries. The present study was a randomized crossover-controlled trial involving 40 medical residents, conducted in the clinical training center at a hospital with a residency program. The primary outcome measure was the rate of posterior vessel wall injuries. Subjects received a didactic lecture during which the instructors taught three SAX-OOP techniques including the conventional free-hand method (procedure C), a needle navigation system (procedure N), and a shallow puncture angle using a guidance system (procedure S). Participants were trained in these approaches under supervision and each technique tested in a simulation environment. Thirty-four of 40 residents had no previous experience with central venous catheterization and were included in the final analysis. The rate of posterior vessel wall injuries in procedure S (9%) was significantly lower than using the other approaches (procedure C, 53%; procedure N, 41%). In conclusion, a shallow angle of approach using the SAX-OOP technique resulted in significantly fewer posterior vein wall injuries in central venous catheterization compared with steep angle techniques.

Comparison of transverse short-axis classic and oblique long-axis “Syringe-Free” approaches for internal jugular venous catheterization under ultrasound guidance

Background and objectives

Methods

Results

Conclusion

Safety and efficacy of the oblique-axis plane in ultrasound-guided internal jugular vein puncture: A meta-analysis

Objective This meta-analysis was performed to evaluate the safety and efficacy of the oblique-axis plane in ultrasound-guided internal jugular vein puncture. Methods We searched Embase, PubMed, the Cochrane Library, Web of Science, and China National Knowledge Infrastructure for relevant randomized clinical trials comparing the oblique axis with the short axis in ultrasound-guided internal jugular vein puncture. Results Five randomized clinical trials were included in this meta-analysis. The pooled meta-analysis showed that the incidence of arterial puncture in the oblique-axis group was significantly lower than that in the short-axis group. No significant difference was found in the first-pass success rate between the oblique-axis group and short-axis group. Additionally, there were no significant differences in the puncture success rate or number of attempts required between the two groups. Conclusion Ultrasound-guided internal jugular vein puncture using the oblique-axis plane reduced the risk of arterial puncture, but no difference was found in the first-pass success rate, puncture success rate, or number of attempts required.

Simulated internal jugular vein cannulation using a needle-guiding device

BACKGROUND

Using a two-dimensional ultrasound-guided approach does not guarantee success during the first attempt at internal jugular vein cannulation. Our randomized, parallel simulation study examined whether a new disposable device could improve the success rate of the first attempt at ultrasound-guided internal jugular vein cannulation of a simulated internal jugular vein.

METHODS

Eighty-eight participants were randomized to perform needle insertion for internal jugular vein cannulation of a phantom using the ultrasound-guided approach with (case group) or without (control group) this new device. The primary outcome was the success rate of the first attempt. The secondary outcome was the frequency of mechanical complications such as arterial puncture and posterior wall puncture, procedure time, and level of difficulty.

RESULTS

Among 44 participants using the device, 33 (75.0%) achieved successful cannulation on the first attempt. However, only 12 (27.3%) of the 44 participants not using the device recorded success during the first attempt (risk difference, 0.477; 95% confidence interval [CI] 0.294-0.661; P<0.001). The number of attempts was significantly lower (risk difference, -3.955; 95% CI, -5.014 to -3.712; P<0.001) when participants performed cannulation with the device (1.63±1.71) than without the device (5.59±5.78). Our study also showed that participants were comfortable when performing the ultrasound-guided approach with the new device (risk difference, -1.955; 95% CI, -2.016 to -1.493; P<0.0001).

CONCLUSIONS

The new disposable device was effective for successful first attempts at needle insertion during ultrasound-guided internal jugular vein cannulation. Future clinical trials are needed to assess the effectiveness of this device.

Comparison between the long-axis/in-plane and short-axis/out-of-plane approaches for ultrasound-guided vascular catheterization: an updated meta-analysis and trial sequential analysis

Background

A long-axis in-plane (LA-IP) approach and a short-axis out-of-plane (SA-OOP) approach are the two main approaches used in ultrasound (US)-guided vascular catheterization. However, the efficacy and safety of these approaches remain controversial. Therefore, we performed this meta-analysis to compare the two techniques in vascular catheterization.

Materials and methods

Relevant studies were searched in PubMed, Embase, and the Cochrane Library databases from database inception until August 2017. Randomized controlled trials comparing a long-axis approach with a short-axis approach for US-guided vascular cannulation were selected. The RevMan software was used to analyze the results, and trial sequential analysis (TSA) was further applied to determine whether the currently available evidence was sufficient and conclusive.

Results

Eleven studies met the inclusion criteria. Overall, 1,210 patients were included. The total success rate was similar between the SA-OOP and LA-IP approaches for US-guided vascular catheterization (risk ratio [RR], 1.01; 95% CI, 0.99–1.04; P=0.35; I²=48%). In the radial artery (RA; RR, 1.00; 95% CI, 0.96–1.05; P=0.88; I²=49%) and internal jugular vein (IJV; RR, 1.00; 95% CI, 0.98–1.02; P=0.99; I²=0%) subgroups, the total success rate was also similar and was confirmed by the TSA. For populations with subclavian vein (SCV) and axillary vein catheterization, the SA-OOP approach showed a benefit for first-attempt success rate. No significant differences in first-attempt success rate, cannulation times, or complications were found between the two approaches.

Conclusion

Despite a similar total success rate between the SA-OOP approach and the LA-IP approach when used for RA and IJV catheterization (as confirmed by TSA), further robust well-designed trials are warranted to evaluate other outcomes. There is insufficient evidence to definitively state that the SA-OOP approach was superior to the LA-IP approach when used for SCV and axillary vein catheterization. High-quality trials are needed to confirm or refute this finding.

A comparison of longitudinal and transverse approaches to ultrasound-guided axillary vein cannulation by experienced operators

BACKGROUND

The axillary vein is an easily accessible vessel that can be used for ultrasound-guided central vascular access and offers an alternative to the internal jugular and subclavian veins. The objective of this study was to identify which transducer orientation, longitudinal or transverse, is better for imaging the axillary vein with ultrasound.

METHODS

We analyzed 236 patients who had undergone central venous cannulation of axillary vein in this retrospective study. Patients were divided into two groups, the longitudinal approach group (n=120) and transverse approach group (n=116). Recorded the one-attempt success rate, operation time, arterial puncture rate and pneumothorax rate. We perform chest radiography to confirm pneumothorax on all patients. We compared the one-attempt success rate, operation time, arterial puncture rate and pneumothorax rate between the two groups.

RESULTS

The two groups were comparable with clinical characters of patients. The overall success rates of the longitudinal group and the transverse group were both 100%. The rate of one-attempt success in the longitudinal approach group is higher than the transverse approach group (91.7% vs. 82.8%, P=0.040). The transverse approach group had shorter operation time than the longitudinal group (184.7±8.1 vs. 287.5±19.6 seconds, P=0.000). The two groups had lower postoperative complications. Arterial puncture occurred in 1 of 120 longitudinal and 2 of 116 transverse attempts and this difference was no significant (P=0.541). No pneumothorax occurred in the two groups.

CONCLUSIONS

The longitudinal approach during ultrasound-guided axillary vein cannulation is associated with greater one-attempt success rate compared with the transverse approach by experienced operators. The transverse approach has shorter operation time. The two groups have lower postoperative complications and are comparable with pneumothorax and arterial puncture.

The Use of Ultrasonography in Obstetric Anesthesia

This article provides an overview of the use of ultrasonography in obstetric anesthesia. It discusses the indications, benefits, and techniques of using ultrasonography to optimize the delivery of anesthesia and provide safe and efficacious clinical care. More specifically, it discusses the use of ultrasonography to facilitate neuraxial anesthesia, abdominal field blocks, central and peripheral vascular access, as well as the assessment of the lung fields and gastric contents, and identification of the cricothyroid membrane.

Retrospective comparison of two different approaches for ultrasound-guided internal jugular vein cannulation in hemodialysis patients

Background

Prevalent hemodialysis patients with vascular access consisting of a central venous catheter (CVC) are continuously increasing over the years. Improvement in evolution and CVC placement procedures represents therefore an essential tool to enhance performance and reduce intraoperative and long-term CVC complications. Internal jugular vein (IJV) catheterization techniques are different according to ultrasound probe position in relation to vein axis and to needle direction in relation to ultrasound beam. Lateral in-plane (LIP) approach has been proposed to be advantageous compared to traditional anterior out-of-plane (AOP) technique.

Methods

In this retrospective nonrandomized study we evaluated outcomes of 337 hemodialysis CVCs positioned in our center (Dono Svizzero Hospital) between 2011 and 2016, 237 using the AOP technique and 100 using the LIP approach.

Results

We found no significant differences among considered outcomes (procedure success, arterial puncture, pneumothorax, first-use malfunction, kinking/pinching) between the two approaches.

Conclusions

In our experience AOP and LIP approaches have shown the same outcomes. However, we believe that the LIP technique has potential benefits and it should be considered in the decision process of IJV cannulation.