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Abstract
Introduction Central venous catheters are indispensable in modern healthcare. Unfortunately, they are accompanied by minor as well as major complications, leading to increased morbidity, mortality and costs. Immediate insertion-related complications (mechanical complications) have decreased due to the implementation of real-time ultrasound guidance, but they still occur and additional efforts to enhance patient safety are warranted. This study aims to investigate whether the use of a needle guide mounted on the ultrasound probe in subclavian catheterisations may decrease the number of catheterisations with >1 skin puncture (primary outcome).
Methods and analysis This is an investigator-initiated, non-commercial, randomised, controlled, parallel-group study conducted at Skåne University Hospital, Lund, Sweden. Adults (≥18 years) with a clinical indication for a subclavian central venous catheter and the ability to give written informed consent will be eligible for inclusion. Exclusion criteria include subclavian catheterisation deemed unsuitable based on the preprocedural ultrasound examination. Patients will be randomised to catheterisation by certified operators using a microconvex probe (long-axis, in-plane technique) with (n=150) or without (n=150) a needle guide. The ultrasound imaging from the procedures will be recorded and assessed by two reviewers individually. The assessors will be blinded for group affiliation. Secondary outcomes include the total number of skin punctures, mechanical complications, time to successful venous puncture, number of failed catheterisations and operator satisfaction with the needle guide at the end of the study period.
Recruitment started on 8 November 2022 and will continue until the sample size is achieved.
Ethics and dissemination This study was approved by the Swedish Ethical Review Authority (#2022-04073-01) and the Swedish Medical Products Agency (#5.1-2022-52130; CIV-21-12-038367). The findings will be submitted to an international peer-reviewed journal.
Trial registration number NCT05513378, clinicaltrials.gov.
- Ultrasonography
- Clinical Trial
- ANAESTHETICS
- INTENSIVE & CRITICAL CARE
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Strengths and limitations of this study
This is a randomised controlled trial performed in a clinical setting with a diverse patient clientele.
Operators with varying degree of experience will perform the catheterisations.
Assessor-blinded reviews of the ultrasound recordings decrease the risk of bias.
The generalisability of the results is reduced due to the single-centre design.
Due to the nature of the study, blinding of the intervention is not possible.
Introduction
Central venous catheters (CVCs) are indispensable and common in modern healthcare, with approximately 27 million annual insertions worldwide,1 making them one of the most common invasive procedures at hospitals. Unfortunately, the insertion procedure comes with complications and patient discomfort.2 Insertion-related complications (bleeding, cardiac arrhythmia, arterial puncture, pneumothorax and nerve injury) are usually referred to as mechanical complications, with a severity ranging from minor to major. The incidence of mechanical complications has been investigated in several previous studies and is reported to be 1.1%–18%,3–13 leading to an increase in morbidity, mortality, costs and patient suffering, meaning that further efforts to increase patient safety are needed.
Numerous studies have shown that real-time ultrasound (US) guidance during the catheterisation procedure improves the success rate and decreases complications,14–17 and it is therefore recommended by guidelines.18–22
CVCs inserted in the subclavian vein have been demonstrated to be less prone for catheter-related infections and thrombotic complications8 9 and also less uncomfortable for the patient compared with other sites (internal jugular vein, external jugular vein and femoral vein).23 24 However, CVC insertions in the subclavian vein have also been shown to be associated with more mechanical complications (mainly pneumothorax) than insertions in the other locations.6 8 9 11 13 25 26
At the current department, real-time US guidance using the long-axis approach with an in-plane needling technique is recommended for subclavian vein catheterisation. The main advantage of this technique is the ability to visualise both the needle, needle tip and vessel throughout the entire procedure, minimising the risk of mechanical complications by accidental puncture of adjacent arteries or pleura. However, keeping the needle and needle tip in the limited US field of vision can often be challenging, and a needle guide mounted on the US probe may facilitate good visual control during the procedure.
To the best of our knowledge, there are only two previous studies where the efficacy of this intervention has been investigated. Mao et al concluded that, during US-guided catheterisation of the subclavian vein using the long-axis approach with an in-plane needling technique, the aiming method (ie, freehand) provided comparable needle-beam alignment with a lower cannulation time than the needle guide technique and was associated with fewer skin breaks.27 On the other hand, Maecken et al found that a needle guide significantly improved alignment of the needle and the US plane compared with the freehand technique when cannulating the subclavian vein using the long-axis approach with an in-plane needling technique and use of the needle guide resulted in faster access times and increased success at the first and second attempts.28 In both studies, only a limited number of individual operators performed the cannulations, and the majority of patients were under general anaesthesia, making the results difficult to generalise.
Aim and hypothesis
To clarify the inconsistent results from the Mao and Maecken studies, we aim to investigate the efficacy of a needle guide in wide clinical practice, including awake patients and operators with varying experience. The hypothesis is that the addition of a needle guide, in US-guided catheterisation of the subclavian vein using the long-axis approach with an in-plane needling technique, will reduce the number of CVC insertions with >1 skin puncture.
Methods and analysis
Study design
This is an investigator-initiated, non-commercial, randomised, controlled, parallel group study. Patients will be enrolled at Skåne University Hospital in Lund, Sweden. A flowchart of the study can be found in online supplemental appendix A. The study protocol was written in accordance with the SPIRIT guidelines.29
Supplemental material
Primary outcome
Number of CVC insertions with >1 skin puncture.
Secondary outcomes
Frequency of mechanical complications (defined as bleeding, arterial puncture, arterial catheterisation, nerve injury and pneumothorax and divided into minor and major complications, as described in table 1).
Access time (time to successful venous puncture).
Number of skin punctures.
Number of failed catheterisations.
Operator satisfaction concerning the use of the needle guide, measured at the end of the study period.
Mechanical complications
Study population and intervention
Adult (≥18 years) patients at Skåne University Hospital, Lund, Sweden, in need of a subclavian CVC (assessed by the operator) and able to give written informed consent (online supplemental appendix B) will be eligible for inclusion. In agreement with clinical guidelines, patients will undergo a preprocedural US scan of the subclavian vein(s) by the operator to ensure suitability for subclavian catheterisation. Both elective and emergency patients can be included. The study subjects will be randomised to real-time US-guided subclavian CVC insertion with (intervention) or without (control) the needle guide mounted on the US probe.
Supplemental material
Enrolment started on 8 November 2022 and will continue until the calculated sample size is achieved, which is estimated to be in December 2024.
Inclusion criteria
≥18 years.
In need of a CVC with a clinical indication for the subclavian route assessed by the operator.
Signed informed consent.
Exclusion criteria
Subclavian catheterisation is deemed unsuitable based on the preprocedural US examination or due to unacceptable patient risk in case of a mechanical complication (eg, severe respiratory failure).
Sample size calculation
We want to reduce the number of CVC insertions with >1 skin puncture to 10% by using the needle guide. Given that >1 skin puncture was used in 20.4% of all subclavian CVC insertions performed without a needle guide according to our Regional Quality Register (March 2019 to May 2022), we would need 146 patients per group to reach 80% power and a one-sided significance level of 5% (G*power, V.3.1). To allow for dropouts, this was adjusted to 150 patients per group.
Randomisation and blinding
Certified operators and research nurses will be responsible for screening patients eligible for inclusion and for obtaining consent. Included patients will be randomised to US-guided CVC insertion in the subclavian vein (dx/sin) using the long-axis approach with an in-plane needling technique with or without the needle guide. The randomisation will be performed by members of the steering committee or dedicated research nurses. REDCap (Research Electronic Data Capture, a browser-based, metadata-driven electronic data capture software, powered by Vanderbilt University, Nashville, USA) will be used as the randomisation tool and as the electronic case report form (eCRF). In addition, the randomisation will be performed in blocks with varying size (2, 4 and 6). Given the nature of the study, operators cannot be blinded for the intervention. However, assessor of the ultrasound recordings will be blinded for the group affiliation.
Catheterisation procedure
All anaesthesiologists at the participating department who can independently insert a CVC in the subclavian vein using the long-axis approach with an in-plane needling technique will be invited to participate as operators in the study. Those who accept the invitation must attend a mandatory 45-min education session (held by members of the steering committee) regarding the needle guide and the randomisation procedure and fill out a curriculum vitae (online supplemental appendix C), before certification as operators within the study.
Supplemental material
All catheterisations will be performed in a standardised manner with a microconvex probe, using the infraclavicular, long-axis approach with an in-plane needling technique. For patients randomised to the intervention group, the Ultra-Pro II Needle Guidance System (bracket model C8-5 Philips, angle C, with Ultra-Pro e Disposable Variable Angle Replacement Kit; CIVCO Medical Solutions, Coralville, USA) will be mounted on the US probe (figure 1). All catheterisations will be performed using an 18 G echogenic steel cannula (VascularSono; Pajunk, Geisingen, Germany). As the needle guide prevents the last 20 mm of the steel cannula from being inserted, a 100 mm needle will be used for patients in the intervention group, and a 70 mm needle (standard length) will be used for patients in the control group.
The Ultra-Pro II needle guidance system mounted on the ultrasound probe.
Documentation and data collection
The details of the CVC insertion will be documented in a CVC insertion template in the electronic medical record according to departmental practice, for later automated retrieval, (online supplemental table 1). All outcomes, except operator satisfaction, will be registered in the eCRF along with patient baseline data (eg, age, sex, height, weight, platelet count, routine coagulation status, haemoglobin level, ongoing anticoagulants, procedural sedation, mechanical ventilation and use of local anaesthesia). The number of skin punctures is determined by the operator and the assistant together. Operator experience, classified as the number of subclavian CVC insertions using the long-axis approach with an in-plane needling technique and number of years in practice when entering the study as a certified operator, will be measured.
Supplemental material
The US images from the catheterisation will be recorded and saved for postprocedural blinded analyses of time to successful venous puncture, depth of the subclavian vein and diameter and collapsibility of the subclavian vein at the point of vessel puncture. The analyses will be assessor-blinded and performed by two reviewers individually in a standardised manner (online supplemental appendix D).
Supplemental material
Postcatheterisation and follow-up
If the catheterisation was complicated, US is used to verify/rule out pneumothorax and/or haematoma formation. To identify any pneumothorax and evaluate the catheter tip position, a postprocedural chest X-ray will be performed in all patients. This study requires no other follow-up beyond that.
Adverse events
All serious adverse events suspected to be caused by the intervention will be reported to the principal investigators without delay. A serious adverse event is defined as a major mechanical complication, as defined in table 1.
Questionnaire
A questionnaire (online supplemental appendix E) regarding operator satisfaction with the needle guide will be completed by each operator at the end of the study.
Supplemental material
Exit from the trial
A study participant is free to exit the trial at any time without explanation.
Statistical plan and analysis
Analyses in the study will be performed according to intention-to-treat principles. Continuous variables following a symmetrical distribution will be presented as the mean (SD), while skewed variables will be presented as the median (IQR). Categorical variables will be presented as n (%).
Outcomes
Binary variables such as ‘Number of CVC insertions with >1 skin puncture’ (primary outcome), ‘Mechanical complications’ (merged into two composite variables; table 1) and ‘Failed catheterisations’ will be analysed and described using a 95% CI for the difference between the proportions, calculated as event rate intervention group—event rate control group. Continuous variables such as ‘Access time’ and ‘Number of skin punctures’ will be compared between the groups using a suitable parametric or non-parametric t-test, depending on normal distribution or not.
Ordinal variables, such as the 10-point satisfactory scale for operator use of the needle guide, will be presented with median (IQR) but may also be reported with the actual number in each category or dichotomised, based on clinical relevance of values below and over the split value.
Additional analyses
In case of obvious imbalance in baseline characteristics between groups, sensitivity analyses including tests where baseline characteristics can be stratified (eg, the Cochran-Mantel-Haenszel test or logistic regression analyses) will be used.
To investigate whether the needle guide is especially useful in selected cases, we plan to perform additional analyses. Examples of such analyses are the following:
The same analyses as in the main dataset but only with cases where the subclavian vein is located deep and/or with high collapsibility.
Logistic regression analyses with the primary outcome as dependent variable and carefully selected independent variables including group affiliation, based on clinical relevance and results of preanalytical univariate analyses.
The same analyses as in the main dataset but only include cases with high BMI.
Missing data
Missing data will be reported, and if it is not valid to ignore missing data, we will consider using sensitivity analyses including imputation of missing data and others.
Data management and confidentiality
All data will be stored and handled according to the Swedish Data Protection Regulation. Patients will be identified by a study number in REDCap to ensure confidentiality. The code linking a study number to a specific patient will be stored in a computer in a secure location within the hospital premises. REDCap access will be restricted to the trial steering committee and research nurses. All original records (consent forms, questionnaires, relevant correspondence) will be retained for 15 years to allow inspection by relevant authorities. The US recordings will be stored for 10 years.
Quality control
The trial will be monitored by independent research nurses who are not involved in the study. The frequency of the monitoring will depend on compliance with the protocol, number of enrolled participants and data handling. At a minimum, there will be a pretrial meeting and mandatory monitoring after the trial and once during the trial period. The site investigator will be responsible for all relevant data to be entered into the eCRF. The eCRF is constructed to assure data quality with predefined values and ranges on all data entries. If any important protocol modifications are needed, they will be communicated to all relevant parties by the sponsors.
Patient and public involvement
The research questions emerged from the authors’ own clinical experience and former scientific studies.
Patients and the public were not involved in the study design, but the study was developed in the interest of patients, aiming to increase patient safety and satisfaction.
Ethics and dissemination
Ethical approval
The study was approved by the Swedish Ethical Review Authority (#2022-04073-01) and the Swedish Medical Products Agency (#5.1-2022-52130; CIV-21-12-038367) and will be performed according to good clinical practice guidelines and according to the statement of ethical principles in the Declaration of Helsinki. All patients included in the study will have an assessed clinical need of a subclavian CVC, independent of the study, and will give signed informed consent prior to inclusion. Furthermore, all operators will give signed informed consent for the anonymous compilation of the answers to the questionnaire concerning the usefulness of the needle guide.
Ethics statements
Patient consent for publication
Acknowledgments
The work is supported by the Tegger Foundation (2022), LN; the Swedish state under the agreement between the Swedish government and the county councils and the ALF agreement (2022:0071), TK; Skåne University Hospital Foundations and Donations (2022), OB and TK; regional project funds, Region Skåne (2022), OB; the Swedish Society of Medicine (2023:984669), TK; Magnus Bergvall Foundation (2022), TK; LÖF, the Swedish Patient Insurance (2023), TK.
References
Supplementary materials
Supplementary Data
This web only file has been produced by the BMJ Publishing Group from an electronic file supplied by the author(s) and has not been edited for content.
Footnotes
Contributors TK conceived the study. LN, OB and TK are the sponsors. TK and LN are the principal investigators. All authors contributed to the study design and planning. LN wrote the first versions of the applications to the Swedish Ethical Review Authority and the Swedish Medical Products Agency, the questionnaire and the study protocol, and OB, MA, BB and TK critically revised them. LN and OB wrote the first version of the US recording review protocol, and MA, BB and TK critically revised it. All authors revised the study protocol, gave their final approval of the version to be published and agreed to be accountable for all aspects of the study protocol. TK is the guarantor, responsible for the overall content.
Funding We would like to thank research nurse Susann Schrey for assistance with the logistical planning of the study.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.