SUPPLEMENTAL DIGITAL CONTENT
Real-Time Ultrasound Guidance as compared to Landmark Technique for Subclavian Central Venous Cannulation: a Systematic Review and Meta-Analysis with Trial Sequential Analysis
Table of contents:
PICOS and search strategy – page 2
PRISMA Checklist – page 3-5
PRISMA Flowchart – page 6
Forest plot rate of success on first attempt – page 7
Risk of bias assessment – page 8
Grade of Evidence – page 9
Trial Sequential Analyses – page 10 - 14
The overall success rate as compared to landmark technique – page 15
Summary of the evidence from meta-analysis and population risk – page 16
Supplementary digital content 1. “PICOS” approach for selecting clinical studies in the systematic search and meta-analysis.
Population Adult patients receiving central venous catheterization in the subclavian/axillary vein Intervention Real-time ultrasound-guided dynamic approach
Comparison Anatomical landmark technique
Outcomes Primary: Overall success rate; Number of complications.
Secondary: Success at first attempt; Number of attempts; Time to puncture.
Study design Randomised control trials
Search strategy
The PubMed search was carried out from the inception of the database until the 1st June 2022; the EMBASE search was restricted to the last 5 years.
Our core search was structured by combining findings in title and abstracts from three groups of terms: a)
(subclavian OR axillary OR supraclavicular) AND (ultrasound OR US OR ultrasonic), AND b) (central line* OR
insertion* OR cannulation OR access OR catheter* OR puncture OR venous OR vein* OR central venous line*),
AND c) (randomized controlled trial OR controlled clinical trial OR prospective).
Supplementary digital content 2. PRISMA Checklist
Section and
Topic Item
# Checklist item Location where
item is reported TITLE
Title 1 Identify the report as a systematic review. 1
ABSTRACT
Abstract 2 See the PRISMA 2020 for Abstracts checklist. 2
INTRODUCTION
Rationale 3 Describe the rationale for the review in the context of existing knowledge. 3-4
Objectives 4 Provide an explicit statement of the objective(s) or question(s) the review addresses. 3-4 METHODS
Eligibility criteria 5 Specify the inclusion and exclusion criteria for the review and how studies were grouped for the syntheses.
6 Information
sources 6 Specify all databases, registers, websites, organisations, reference lists and other sources searched or
consulted to identify studies. Specify the date when each source was last searched or consulted. 6 Search strategy 7 Present the full search strategies for all databases, registers and websites, including any filters and limits
used. 6
Selection process 8 Specify the methods used to decide whether a study met the inclusion criteria of the review, including how many reviewers screened each record and each report retrieved, whether they worked independently, and if applicable, details of automation tools used in the process.
6
Data collection
process 9 Specify the methods used to collect data from reports, including how many reviewers collected data from each report, whether they worked independently, any processes for obtaining or confirming data from study investigators, and if applicable, details of automation tools used in the process.
6
Data items 10a List and define all outcomes for which data were sought. Specify whether all results that were compatible with each outcome domain in each study were sought (e.g. for all measures, time points, analyses), and if not, the methods used to decide which results to collect.
7
10b List and define all other variables for which data were sought (e.g. participant and intervention characteristics, funding sources). Describe any assumptions made about any missing or unclear information.
7
Study risk of bias
assessment 11 Specify the methods used to assess risk of bias in the included studies, including details of the tool(s) used, how many reviewers assessed each study and whether they worked independently, and if applicable, details of automation tools used in the process.
8
Effect measures 12 Specify for each outcome the effect measure(s) (e.g. risk ratio, mean difference) used in the synthesis or 7
Section and Topic
Item
# Checklist item Location where
item is reported presentation of results.
Synthesis methods 13a Describe the processes used to decide which studies were eligible for each synthesis (e.g. tabulating the study intervention characteristics and comparing against the planned groups for each synthesis (item #5)). 6 13b Describe any methods required to prepare the data for presentation or synthesis, such as handling of
missing summary statistics, or data conversions. 7
13c Describe any methods used to tabulate or visually display results of individual studies and syntheses. 7 13d Describe any methods used to synthesize results and provide a rationale for the choice(s). If meta-
analysis was performed, describe the model(s), method(s) to identify the presence and extent of statistical heterogeneity, and software package(s) used.
7-8
13e Describe any methods used to explore possible causes of heterogeneity among study results (e.g.
subgroup analysis, meta-regression). 7
13f Describe any sensitivity analyses conducted to assess robustness of the synthesized results. 7 Reporting bias
assessment 14 Describe any methods used to assess risk of bias due to missing results in a synthesis (arising from
reporting biases). 8
Certainty
assessment 15 Describe any methods used to assess certainty (or confidence) in the body of evidence for an outcome. 8 RESULTS
Study selection 16a Describe the results of the search and selection process, from the number of records identified in the
search to the number of studies included in the review, ideally using a flow diagram. 8-11 and supplementary 16b Cite studies that might appear to meet the inclusion criteria, but which were excluded, and explain why
they were excluded. 8 and
supplemetary Study
characteristics 17 Cite each included study and present its characteristics. 8-9 and table 1
Risk of bias in
studies 18 Present assessments of risk of bias for each included study. 11 and
supplementary Results of
individual studies 19 For all outcomes, present, for each study: (a) summary statistics for each group (where appropriate) and (b) an effect estimate and its precision (e.g. confidence/credible interval), ideally using structured tables or plots.
8-11
Results of
syntheses 20a For each synthesis, briefly summarise the characteristics and risk of bias among contributing studies. 8-11 and supplementary 20b Present results of all statistical syntheses conducted. If meta-analysis was done, present for each the
summary estimate and its precision (e.g. confidence/credible interval) and measures of statistical 8-11
Section and Topic
Item
# Checklist item Location where
item is reported heterogeneity. If comparing groups, describe the direction of the effect.
20c Present results of all investigations of possible causes of heterogeneity among study results. 8-11 20d Present results of all sensitivity analyses conducted to assess the robustness of the synthesized results. 11 Reporting biases 21 Present assessments of risk of bias due to missing results (arising from reporting biases) for each
synthesis assessed. 11 and
supplementary Certainty of
evidence 22 Present assessments of certainty (or confidence) in the body of evidence for each outcome assessed. 11 DISCUSSION
Discussion 23a Provide a general interpretation of the results in the context of other evidence. 12-15
23b Discuss any limitations of the evidence included in the review. 14-15
23c Discuss any limitations of the review processes used. 14-15
23d Discuss implications of the results for practice, policy, and future research. 14-16 OTHER INFORMATION
Registration and
protocol 24a Provide registration information for the review, including register name and registration number, or state
that the review was not registered. 6
24b Indicate where the review protocol can be accessed, or state that a protocol was not prepared. - 24c Describe and explain any amendments to information provided at registration or in the protocol. N/A Support 25 Describe sources of financial or non-financial support for the review, and the role of the funders or
sponsors in the review. 1
Competing
interests 26 Declare any competing interests of review authors. 1
Availability of data, code and other materials
27 Report which of the following are publicly available and where they can be found: template data collection forms; data extracted from included studies; data used for all analyses; analytic code; any other materials used in the review.
Table 1, On request
Supplementary digital content 3. Prisma flow chart
Supplementary digital content 4. Forest plot of rate of success on first attempt. Comparison is made between
patients according to the use of US-guided subclavian cannulation vs landmark technique. CI: confidence
interval; IV: Inverse Variance
Supplementary digital content 5. Risk of bias assessment
Study Random
sequence generation
Allocation
concealment Blinding of participants
and personnel
Blinding of outcome assessment
Incomplete outcome
data
Selective outcome reporting
Overall
Subramony 2022
Low Unclear/NR Unclear Unclear/NR High High High
Singam 2019 Low Unclear/NR Unclear Unclear/NR Low Low Low
Sazdov 2017 Low Unclear/NR Unclear Unclear/NR Low Low Low
Fragou 2011 Low Unclear/NR Unclear Unclear/NR Low Low Low
Palepu 2009 Low Unclear/NR Unclear Unclear/NR Low Low Low
Gualtieri 1995 Low Unclear/NR Unclear Unclear/NR Low Low Low
Study Bias due to confoundin
g
Bias due to selection of participants
Bias in classification of
interventions
Bias due to deviation from intended
interventions
Bias due to missing
data
Bias in measurement
of outcomes
Bias in selection of the reported
results
Overall
Sidoti 2019 Moderate Low Low Low Low Low Low Low
Supplementary digital content 6. Grade of Evidence according to Grading of Recommendations Assessment, Development and Evaluation working group
US guided dynamic technique compared to Landmark guided technique for subclavian CV catheterization
Bibliography:
Certainty assessment Summary of findings
Participan ts (studies) Follow-up
Risk of
bias Inconsisten
cy Indirectne
ss Imprecisio
n Publication bias
Overall certainty
of evidence
Study event rates (%)
Relative effect (95% CI)
Anticipated absolute effects
With Landmark
guided technique
With US guided dynamic technique
Risk with Landmark
guided technique
Risk difference
with US guided dynamic technique
Success rate
805 (6 RCTs)
not serious
not serious seriousa seriousb none ⨁⨁◯◯
Low
346/418 (82.8%)
374/387 (96.6%)
RR 1.14 (1.06 to 1.23)
828 per 1.000
116 more per 1.000 (from 50 more
to 190 more)
Number of attempts
623 (3 RCTs)
not serious
not serious seriousa seriousb none ⨁⨁◯◯
Low
322 301 - The mean
number of attempts
was 0
MD 0.45 lower (0.57 lower to
0.34 lower)
Complication rate
Supplementary digital content 6. Grade of Evidence according to Grading of Recommendations Assessment, Development and Evaluation working group
US guided dynamic technique compared to Landmark guided technique for subclavian CV catheterization
Bibliography:
Certainty assessment Summary of findings
720 (5 RCTs)
not serious
not serious seriousa seriousb none ⨁⨁◯◯
Low
102/375 (27.2%)
30/345 (8.7%)
RR 0.32 (0.22 to 0.47)
272 per 1.000
185 fewer per 1.000 (from 212 fewer to 144
fewer)
Success rate at first attempt
267 (3 RCTs)
not serious
not serious seriousa seriousb none ⨁⨁◯◯
Low
92/149 (61.7%)
97/118 (82.2%)
RR 1.32 (1.14 to 1.54)
617 per 1.000
198 more per 1.000 (from 86 more
to 333 more)
Access time
613 (3 RCTs)
not serious
not serious seriousa seriousb none ⨁⨁◯◯
Low
322 291 - The mean
access time was 0
MD 10.14 lower (17.34 lower to 2.94 lower) CI: confidence interval; MD: mean difference; RR: risk ratio
Explanations
a. Population included in the studies varied regarding the clinical conditions and the ventilation support b. The operator experience and training varied greatly across the studies
Supplementary digital content 7. Trial Sequential Analyses
A -TSA for Rate of success on first attempt
B - TSA for Number of attempts
C - TSA for Complication rate
D - TSA for Access time
Supplementary Digital Content 8. Summary of the results of the meta-analysis.
Outcome N
studies
N procedure
s
RR or MD with 95%CI P value I
2Success rate 6 805 RR 1.14; [1.06, 1.23] 0.0007 55%
Rate of success on first attempt 3 267 RR 1.32; [1.14, 1.54] 0.0003 0%
Number of attempts 3 623 MD -0.45; [-0.57,-0.34] <0.00001 0%
Complication rate 5 720 RR 0.32; [0.22, 0.47] <0.00001 0%
Access time 3 613 MD -10.14; [-17.34, -2.94] 0.009 77%
Supplementary Digital Content 9. Baseline risk
Outcomes US guided Landmark guided RR / Mean difference Number of
participants (studies) Success at first attempt 822 per 1000
(97/118)
617 per 1000 (92/149)
1.32[1.14, 1.54] 267 (3)
Overall success rate 966 per 1000 (374/387)
828 per 1000 (346/418)
1.14[1.06, 1.23] 805 (6)
Complication rate 87 per 1000 (30/345)
272 per 1000 (102/375)
0.32[0.22,0.47] 720 (5)
Access time 24±10.45 36.49±40.97 -10.14 [-17.34,-2.94] 613 (3)
Number of attempts 1.13±0.38 1.59 ±0.96 -0.45 [-0.57,-0.34] 623 (3)
