Challenges in Hemodialysis: An Analytic Study of Nurses’ Cannulation Failures

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is a good article but has several missing data:

1. Where is the fistula: forearm, upperarm, lower extrimity? Is it in cephalic, basilic or saphenous area?
2. What is the size of vein that is cannulated? Is the veins is aneurysmal or no? How much is the depth of the vein from skin surface?
3. Waht is the BMI of the patients?
4. Whatt type of skin do they have? a very thin skin suach in coticosteroid treated patients or very thich skin in patients with chronic Type I diabetes, or normal skin?
5. How much is the flow of the AV fistula?
6. How much is the flow of the dialysis machine? What type and trade mark of dialysisi machine is used in your center?
7. jow much is the distance between the two needles?
8. How mucc is the duration of dialysis by the fitula from the first session till the first failure?
9. Is the rope ladder method is the routine or do you use the button-hole technique in all your patients?
10.  What kind and trademark of the fistula needle is used in your center?
11. What is the percentage of your patients with several sessions of first attemt failure?

Author Response

Response to the comments of Reviewer 1

 

Challenges in Hemodialysis: An Analytic Study of Nurses’ Cannulation Failures

 

We would like to sincerely thank the Editor for the time, effort, and careful consideration dedicated to handling our manuscript. We are also grateful to the reviewers for their thoughtful comments and constructive suggestions, which have greatly improved the clarity, rigor, and overall quality of this work.

 

Reviewer 1:

 

Quality of English Language

(   ) The English could be improved to more clearly express the research.
( x ) The English is fine and does not require any improvement.

 

	Yes	Can be improved	Must be improved	NA
Does the introduction provide sufficient background and include all relevant references?	X
Is the research design appropriate?		X
Are the methods adequately described?		X
Are the results clearly presented?			X
Are the conclusions supported by the results?		X
Are all figures and tables clear and well-presented?		X

 

 

Comments and Suggestions for Authors

 

This is a good article but has several missing data:

1. Where is the fistula: forearm, upperarm, lower extrimity? Is it in cephalic, basilic or saphenous area?

Specified in 2.4. Study Variables and Measurement “During data collection, no restrictions were applied regarding the anatomical location of AVF or AVG. Access sites included the forearm and upper arm, specifically the cephalic, basilic, and saphenous veins of the upper extremities (radiocephalic, brachiocephalic, and brachiobasilic). No AVF or AVG sites were identified in the lower extremities.”

2. What is the size of vein that is cannulated? Is the veins is aneurysmal or no? How much is the depth of the vein from skin surface?

Added to 2.4. Study Variables and Measurement “Various vein sizes were cannulated; however, all were mature veins, as determined in accordance with the hospital policy on AVF assessment, which includes the “Rule of 6s,” ultrasound evaluation when indicated, and physical examination before each cannulation. The Rule of 6s is a clinical guideline used to determine whether an arteriovenous fistula (AVF) has matured sufficiently for successful hemodialysis cannulation, typically evaluated about 6 weeks after creation. A mature fistula is characterized by adequate vein diameter, appropriate depth from the skin surface, and sufficient blood flow.

According to the commonly accepted Rule of 6s criteria, a mature fistula should have a blood flow greater than 600 mL/min, a vein diameter of at least 6 mm (0.6 cm), a vein depth less than 6 mm (no more than 0.6 cm below the skin surface), and at least 6 cm of usable straight vein for cannulation. When these criteria are met, the fistula is more likely to support successful two-needle dialysis. It is also worth noting that, in accordance with hospital policies and procedures, cannulation of an aneurysmal fistula is prohibited in nursing practice.

3. What is the BMI of the patients?

The BMI was not collected, but all patients included in the study were adults as specified in “Study population and setting”. However, this was acknowledged as a study limitation: “some potentially relevant factors were not included in the data collection sheet and may have influenced fistula cannulation, such as nutritional and inflammatory status and body mass index (BMI)”.

4. What type of skin do they have? a very thin skin such in coticosteroid treated patients or very thick skin in patients with chronic Type I diabetes, or normal skin?

Added in 2.4. Study Variables and Measurement: “Patients had normal skin; none had the abnormally thin or thick skin often seen in individuals treated with corticosteroids or those with long‑standing type I diabetes.”

5. How much is the flow of the AV fistula?

Added in 2.4. Study Variables and Measurement “The AV fistula blood flow during dialysis is typically set at 300 mL/min, in accordance with hospital policies and procedures.”

6. How much is the flow of the dialysis machine? What type and trade mark of dialysisi machine is used in your center?

Added in 2.4. Study Variables and Measurement “The “B. Braun IQ dialysis machine” is used”.

7. How much is the distance between the two needles?

Added in 2.4. Study Variables and Measurement “During cannulation, the distance between the two needles is usually at least 3 cm”.

8. How much is the duration of dialysis by the fitula from the first session till the first failure?

Added in 2.4. Study Variables and Measurement “Each case was separate; some had failure from the first cannulation, others from the next treatment, depending on complications discovered after cannulation and connection to the dialysis machine, such as stenosis, ischemic symptoms in the hand (steal syndrome), and thrombosis.”

9. Is the rope ladder method is the routine or do you use the button-hole technique in all your patients?

Added in 2.4. Study Variables and Measurement “Only the “rope ladder technique” is the standard vascular access method used in our hospital”.

10. What kind and trademark of the fistula needle is used in your center?

Added in 2.4. Study Variables and Measurement “B. Braun fistula needles are used. Needle gauges of 15, 16, and 17 are available, in two lengths: 20 mm and 25 mm.”

11. What is the percentage of your patients with several sessions of first attempt failure?

We cannot specify the percentage of our patients with several sessions of first attempt failure, but it’s small percentage. “Usually, if the next session patient has a failure of attempt after proper assessment, an ultrasound is performed in the unit to determine the reason. If advanced investigation is needed, a venogram is booked for the patient in radiology, and the necessary intervention is performed there. Sometimes, upon doing the ultrasound in the unit, the vascular surgeon can determine the issue and admit the patient for surgery.” This was clarified in 2.4. Study Variables and Measurement.

We thank the reviewer for their constructive and encouraging feedback on our manuscript. All suggested modifications have now been implemented. We hope these revisions adequately address all reviewer’s comments and further improve the clarity and impact of our work.

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you authors for the submission. 

• Please give some methodological and theoretical gaps in the introduction.
• Please be detail in your design. Is it retrospective cohort study ? If it is retrospective cohort, please be detail in  your inception cohort. 
• Please give abbreviations in every table. 
• Please improve the quality of the figure 1. 
• Please follow the STROBE guidelines. 
• Please begin the discussion with the main findings of your study. 
• Please elaborate your findings in the clinical context. 
• The conclusion should be concise and clear. 

Comments on the Quality of English Language

The abbreviations should be included in every tables. 

Author Response

Response to the comments of Reviewer 2

 

Challenges in Hemodialysis: An Analytic Study of Nurses’ Cannulation Failures

 

We would like to sincerely thank the Editor for the time, effort, and careful consideration dedicated to handling our manuscript. We are also grateful to the reviewers for their thoughtful comments and constructive suggestions, which have greatly improved the clarity, rigor, and overall quality of this work.

 

 

Reviewer 2:

Quality of English Language

(x) The English could be improved to more clearly express the research.
( ) The English is fine and does not require any improvement.

 

	Yes	Can be improved	Must be improved	NA
Does the introduction provide sufficient background and include all relevant references?		X
Is the research design appropriate?		X
Are the methods adequately described?		X
Are the results clearly presented?		X
Are the conclusions supported by the results?		X
Are all figures and tables clear and well-presented?		X

 

Comments and Suggestions for Authors

Thank you authors for the submission. 

• Please give some methodological and theoretical gaps in the introduction.

 

Added in the introduction “Although several studies have examined vascular access failure and related complications in hemodialysis patients, most have focused on long‑term patency or access survival rather than on day‑to‑day cannulation success at the unit level. Existing research from Saudi Arabia and the broader Middle East is particularly limited, with few studies assessing patient-, access-, and staff-related predictors of unsuccessful cannulation in routine practice. Furthermore, there is a lack of a comprehensive conceptual framework integrating clinical, anatomical, and procedural factors that may jointly contribute to cannulation failure, especially in high‑volume tertiary centers. Therefore, this retrospective analytic study was conducted to identify factors associated with unsuccessful vascular access cannulation among hemodialysis patients and the actions taken in response to cannulation failure in a tertiary center in the Eastern Region of Saudi Arabia, addressing these methodological and theoretical gaps.”

 

• Please be detailed in your design. Is it retrospective cohort study? If it is retrospective cohort, please be detail in your inception cohort.

The study employed a retrospective cohort study design to identify factors associated with unsuccessful vascular access (VA) cannulation in 228 hemodialysis patients. All adult hemodialysis patients treated at a tertiary center in the Eastern Region of Saudi Arabia between January 1, 2020, and December 31, 2024, who had at least one unsuccessful VA cannulation during the study period were eligible. Data were obtained from electronic medical records and dialysis unit logs.

• Please give abbreviations in every table.

Thank you for this helpful comment. We have now added abbreviations note below each table, defining all non-standard abbreviations used in that table to improve clarity for readers.

• Please improve the quality of the figure 1.

The quality of Figure 1 was improved in the manuscript.

• Please follow the STROBE guidelines.

We thank the reviewer for this important comment. We have revised the manuscript to align more closely with the STROBE reporting guidelines for observational (retrospective cohort) studies. Specifically, we have clarified the study design, setting, eligibility criteria, definitions of exposures and outcomes, data sources, handling of missing data, and statistical methods, and we have ensured that the Results and Discussion sections address the recommended STROBE items (e.g., participant flow, descriptive data, limitations, and generalizability). A completed STROBE checklist indicating where each item is reported has been prepared and can be provided as supplementary material if required.

• Please begin the discussion with the main findings of your study.

We started the discussion with the main findings “Most patients in this cohort had hypertension and diabetes, reflecting a high overall comorbidity burden. Infiltration and clot formation were the predominant manifestations of cannulation failure. Cannulation failures occurred most frequently in patients with vascular comorbidities, with significant associations observed for recurrent stroke, thrombosis, and peripheral vascular disease, whereas no meaningful associations were found with nurse or patient demographic characteristics. Together, these findings suggest that underlying vascular pathology plays a more influential role in cannulation risk than staff experience or educational level in this setting.”

• Please elaborate your findings in the clinical context.

Thank you for this valuable comment. We have expanded the Discussion to more clearly articulate the clinical implications of our findings and we removed the redundant implications at the end of the manuscript. Specifically, we now highlight the need for intensified vascular surveillance and early intervention in patients with vascular comorbidities, the importance of refining cannulation protocols to address the high rates of infiltration and clot formation, and the role of standardized training and procedures in achieving consistent cannulation outcomes irrespective of nurse experience or educational level. These additions clarify how our results can inform day‑to‑day vascular access management in hemodialysis units.

• The conclusion should be concise and clear.

We appreciate this comment. We have revised the Conclusion section to make it more concise and focus on the key findings and their main implications. The updated conclusion now briefly summarizes the principal results (patterns of cannulation failure, the role of vascular comorbidities, and the lack of association with nurse characteristics) and their relevance for vascular access management.

Added “This study highlights the complexity of vascular access management in hemodialysis patients with a high burden of hypertension and diabetes mellitus. Cannulation failure was most often due to infiltration and clot formation and was strongly associated with vascular comorbidities, including recurrent thrombosis, stroke, and peripheral vascular disease, underscoring the central role of underlying vascular health in cannulation outcomes. The absence of significant associations with nursing experience or education suggests that standardized cannulation protocols may help achieve comparable outcomes across staff.”

 

 

Comments on the Quality of the English Language

 

The abbreviations should be included in every tables. 

We have now added abbreviations notes below each table, defining all non-standard abbreviations used in that table to improve clarity for readers.

 

We thank the reviewer for their constructive and encouraging feedback on our manuscript. All suggested modifications have now been implemented. We hope these revisions adequately address all reviewer’s comments and further improve the clarity and impact of our work.

Reviewer 3 Report

Comments and Suggestions for Authors

Please find below a review of the article entitled 'Challenges in Haemodialysis'. An Analytic Study of Nurses' Cannulation Failures'

The article presents a retrospective analysis of the records of 228 patients undergoing dialysis at a single centre (KFMMC, Saudi Arabia) between 2020 and 2024. The aim was to identify factors associated with unsuccessful vascular access cannulations. The introduction is comprehensive and adequately justifies the aim of the study (an increase in ESRD in Saudi Arabia, the importance of arteriovenous fistula, the impact of complications on the patient and the lack of guidelines). The authors accurately identify a research gap concerning the impact of patient and nurse factors on cannulation outcomes.

Overall assesment

The study design is retrospective and single-centre, with the analysis focusing exclusively on patients with at least one documented failed arteriovenous fistula (AVF) or graft (AVG) cannulation. This selection is appropriate if the objective was to illustrate cases of failure; however, it does not permit comparison with a control group that includes failures. Therefore, no conclusions can be drawn about the risk of failure in the dialysis population – only the associations within the group with failure can be described. The sample selection appears adequate for analysing the frequency of different types of complications (e.g. infiltration 61%, clot 30.7%). However, the lack of randomisation and the limitation to a single centre may introduce selection bias and limit the generalisability of the results. As Talari and Goyal point out, retrospective designs are subject to the risk of data gaps and selection bias. The authors themselves indicate in the limitations section that the lack of data and the single-centre nature of the study reduce the generalisability of the work.

Description of methods

The methods are described in detail. Inclusion criteria include adult patients undergoing haemodialysis with an arteriovenous fistula (AVF/AVG) with at least one documented cannulation failure. The variables are clearly defined: demographic (age, gender, comorbidities), access parameters (AVF vs AVG type) and nurse-related variables (diploma/bachelor's degree, <5 vs ≥5 years of experience). The scope of the analyses is also transparent – the main types of complications (infiltration, thrombosis, stenosis, etc.) and actions taken after failure (repeat puncture attempt, catheter placement, session interruption) were identified.

The statistical analysis is based on descriptive statistics and χ² tests to examine the relationships between categories. The authors state that Fisher's test was used for small sample sizes, which is correct for low frequencies in contingency tables. The manuscript also mentions t-tests, but the results do not present any comparisons of means using the Student's t-test, so it appears that their use was ultimately abandoned (all relevant variables are categorical). There is no multivariate analysis (e.g., logistic regression) to control for covariates, which limits the interpretation of the results. Similarly, it is not explained whether only the first failure of each patient or multiple events were analysed – this may affect the independence of the observations. Nevertheless, the description of the methods is understandable and rational, and the choice of statistical tools (chi-square, p<0.05) corresponds to the nature of the data.

Results

The results were presented accurately: the majority of patients had ESRD and hypertension (100%) and a high incidence of diabetes (69.7%). The most common complication of cannulation was infiltration (61%), followed by clotting (30.7%). The analysis demonstrated statistically significant associations between unsuccessful puncture and a history of stroke and peripheral vascular disease (PVD). The authors hypothesise that vascular and nervous system diseases have a substantial impact on the risk of complications, which is logical in the context of impaired circulation. However, no correlation was found with gender, age, type of access or nursing education and experience, which the authors interpret as the effect of standardised treatment protocols.

Overall, the results are consistent with the data presented in the tables, although some conclusions could be presented with more caution. For instance, the absence of a correlation with staff experience does not directly demonstrate the efficacy of the protocols (it may also be attributable to limitations in the sample or a lack of statistical power). In addition, the χ² test for hypertension and ESRD is formally insignificant. However, since 100% of patients had hypertension and ESRD, there was no variability. In practice, it is not possible to test a factor that is present in everyone. Some of the statements (e.g. 'the activities are strongly related to the type of complication' – as clearly shown in Table 4) are well supported by the data. The authors correctly avoid causal claims and instead describe the observed associations. However, it would be advisable to emphasise the conclusions as suggestions rather than certainties.

The clinical significance and contribution to nursing practice

The subject matter is of practical importance – correct fistula puncture is a key nursing skill in haemodialysis. The article indicates that patients with peripheral vascular disease or stroke may require special care and additional procedures (which has not been well described in the context of cannulation before). The authors' conclusions (e.g. the need to develop protocols tailored to patient profiles, regular review of procedures and staff training) are justified and useful in practice.

The study provides local data from the Saudi Arabian region, which may be important given the growing number of dialysis patients and the lack of previous publications on this topic in this context. However, its overall contribution to the literature is moderate. The lack of comparisons with a reference group or multicentre data limits the strength of the recommendations. In nursing practice, the most valuable result is probably the indication of the need for detailed vascular assessment in specific patient groups and the implementation of staff education. There is a paucity of literature on this subject, and the study addresses an important, albeit narrowly defined, problem.

Study's strengths and limitations.

Strengths:

1. Full access to patient records from a real haemodialysis centre was granted, in compliance with ethical principles (the study was approved by a bioethics committee, and the data were anonymised).

2. A comprehensive set of variables has been compiled, including demographic, clinical and procedural details, along with clearly defined categories of complications and staff responses.

3. The following conclusions are based on current practical findings. The work is related to the literature and refers to other studies (e.g. in the discussion) and is up to date (e.g. the meta-analysis by Yan et al. [18] supports the role of diabetes).

Limitations:

1. Retrospective design: potential for data gaps, document heterogeneity, and challenges in establishing causal relationships.

2. It is important to note that results from a single centre cannot be easily generalised to other centres or populations, due to the lack of verification in multiple sites.

3. It is not possible to assess the relative risk of complications in individual subgroups due to the absence of a control group of patients without cannulation failure. For example, it is unclear whether patients with PVD actually have a higher failure rate than others.

4. No multivariate analysis was conducted, for example, the simultaneous impact of several comorbidities was not examined, which could have taken into account the correlations between them.

5. It should be noted that small numbers in some categories (e.g. AVG vs. AVF or rarer complications) may reduce the power of statistical tests and make the results less stable.

6. There are minor issues with the methodology. For example, t-tests are mentioned in the text, but the results are not described, which raises doubts. Furthermore, the repeated introduction of the study objective (lines 377–385 vs. 400–409) suggests minor editorial shortcomings.

Linguistic quality and structure of the article

The text is generally linguistically correct and logically organised (introduction, methods, results, discussion, conclusions). The authors use a professional and factual style.

Recommendation

The paper addresses a topic that is of significance to nurses and appears to be a well-conducted, albeit limited, analytical study. It provides clear, practical conclusions (with particular attention to patients with vascular or post-stroke diseases). Nevertheless, there are a number of corrections to be made prior to publication, including the removal of repetitions, the clarification of the description of methods and reservations regarding statistical tests, and the possible addition of a multivariate analysis or at least a discussion of the lack of power for certain variables. These may assist in further refining the reception of the article. 

I would like to congratulate the authors on their work and recommend publication of the manuscript after minor corrections.

Author Response

Response to the comments of Reviewer 3

 

Challenges in Hemodialysis: An Analytic Study of Nurses’ Cannulation Failures

 

We would like to sincerely thank the Editor for the time, effort, and careful consideration dedicated to handling our manuscript. We are also grateful to the reviewers for their thoughtful comments and constructive suggestions, which have greatly improved the clarity, rigor, and overall quality of this work.

 

Reviewer 3:

Quality of English Language

( ) The English could be improved to more clearly express the research.
(x ) The English is fine and does not require any improvement.

 

	Yes	Can be improved	Must be improved	NA
Does the introduction provide sufficient background and include all relevant references?	X
Is the research design appropriate?	X
Are the methods adequately described?		X
Are the results clearly presented?		X
Are the conclusions supported by the results?	X
Are all figures and tables clear and well-presented?		X

 

Comments and Suggestions for Authors

 

Please find below a review of the article entitled 'Challenges in Haemodialysis'. An Analytic Study of Nurses' Cannulation Failures'

 

The article presents a retrospective analysis of the records of 228 patients undergoing dialysis at a single centre (KFMMC, Saudi Arabia) between 2020 and 2024. The aim was to identify factors associated with unsuccessful vascular access cannulations. The introduction is comprehensive and adequately justifies the aim of the study (an increase in ESRD in Saudi Arabia, the importance of arteriovenous fistula, the impact of complications on the patient and the lack of guidelines). The authors accurately identify a research gap concerning the impact of patient and nurse factors on cannulation outcomes.

 

Overall assesment

 

The study design is retrospective and single-centre, with the analysis focusing exclusively on patients with at least one documented failed arteriovenous fistula (AVF) or graft (AVG) cannulation. This selection is appropriate if the objective was to illustrate cases of failure; however, it does not permit comparison with a control group that includes failures. Therefore, no conclusions can be drawn about the risk of failure in the dialysis population – only the associations within the group with failure can be described. The sample selection appears adequate for analysing the frequency of different types of complications (e.g. infiltration 61%, clot 30.7%). However, the lack of randomisation and the limitation to a single centre may introduce selection bias and limit the generalisability of the results. As Talari and Goyal point out, retrospective designs are subject to the risk of data gaps and selection bias. The authors themselves indicate in the limitations section that the lack of data and the single-centre nature of the study reduce the generalisability of the work.

 

Because we only include patients with at least one cannulation failure and have no control group without failure, we can describe associations within this group but cannot estimate risk or make strong generalizable conclusions.

 

Description of methods

 

The methods are described in detail. Inclusion criteria include adult patients undergoing haemodialysis with an arteriovenous fistula (AVF/AVG) with at least one documented cannulation failure. The variables are clearly defined: demographic (age, gender, comorbidities), access parameters (AVF vs AVG type) and nurse-related variables (diploma/bachelor's degree, <5 vs ≥5 years of experience). The scope of the analyses is also transparent – the main types of complications (infiltration, thrombosis, stenosis, etc.) and actions taken after failure (repeat puncture attempt, catheter placement, session interruption) were identified.

The statistical analysis is based on descriptive statistics and χ² tests to examine the relationships between categories. The authors state that Fisher's test was used for small sample sizes, which is correct for low frequencies in contingency tables. The manuscript also mentions t-tests, but the results do not present any comparisons of means using the Student's t-test, so it appears that their use was ultimately abandoned (all relevant variables are categorical). There is no multivariate analysis (e.g., logistic regression) to control for covariates, which limits the interpretation of the results. Similarly, it is not explained whether only the first failure of each patient or multiple events were analysed – this may affect the independence of the observations. Nevertheless, the description of the methods is understandable and rational, and the choice of statistical tools (chi-square, p<0.05) corresponds to the nature of the data.

 

We analyzed only the first failure per patient without repetition as indicated by the patient's hospital record number.

The statistical design of the manuscript was reviewed to confirm that all mentioned statistical tests were used in our data analysis.

The design was clarified “a single-centered retrospective cohort study design”. Additionally, this was illustrated in the methods and limitations.

 

Results

 

The results were presented accurately: the majority of patients had ESRD and hypertension (100%) and a high incidence of diabetes (69.7%). The most common complication of cannulation was infiltration (61%), followed by clotting (30.7%). The analysis demonstrated statistically significant associations between unsuccessful puncture and a history of stroke and peripheral vascular disease (PVD). The authors hypothesise that vascular and nervous system diseases have a substantial impact on the risk of complications, which is logical in the context of impaired circulation. However, no correlation was found with gender, age, type of access or nursing education and experience, which the authors interpret as the effect of standardised treatment protocols.

Overall, the results are consistent with the data presented in the tables, although some conclusions could be presented with more caution. For instance, the absence of a correlation with staff experience does not directly demonstrate the efficacy of the protocols (it may also be attributable to limitations in the sample or a lack of statistical power). In addition, the χ² test for hypertension and ESRD is formally insignificant. However, since 100% of patients had hypertension and ESRD, there was no variability. In practice, it is not possible to test a factor that is present in everyone. Some of the statements (e.g. 'the activities are strongly related to the type of complication' – as clearly shown in Table 4) are well supported by the data. The authors correctly avoid causal claims and instead describe the observed associations. However, it would be advisable to emphasise the conclusions as suggestions rather than certainties.

Completely correct. This was removed from the abstract, from table 2 and the comments (3.2. Comorbidities), from table 3 and the comments (3.4. Associations between cannulation failure incidence and Comorbidities), and from the discussion (first paragraph)

We acknowledge the absence of multivariable analysis (e.g., logistic regression). This was added to the study limitations.

We thank the reviewer for this observation. We have carefully reviewed the Results section and the tables to minimize redundancy. We believe this approach maintains clarity and supports reader understanding while avoiding unnecessary duplication e.g. Table 1.

Repeated results were also removed from the discussion, for example, “The results of the current study highlight the complex clinical challenges faced by patients undergoing hemodialysis. All participants were diagnosed with ESRD and had hypertension, conditions that often coexist and contribute to vascular compromise. Moreover, the presence of diabetes mellitus in more than two-thirds of the participants further complicates vascular health and healing capacity.”

 

The clinical significance and contribution to nursing practice

 

The subject matter is of practical importance – correct fistula puncture is a key nursing skill in haemodialysis. The article indicates that patients with peripheral vascular disease or stroke may require special care and additional procedures (which has not been well described in the context of cannulation before). The authors' conclusions (e.g. the need to develop protocols tailored to patient profiles, regular review of procedures and staff training) are justified and useful in practice.

The study provides local data from the Saudi Arabian region, which may be important given the growing number of dialysis patients and the lack of previous publications on this topic in this context. However, its overall contribution to the literature is moderate. The lack of comparisons with a reference group or multicentre data limits the strength of the recommendations. In nursing practice, the most valuable result is probably the indication of the need for detailed vascular assessment in specific patient groups and the implementation of staff education. There is a paucity of literature on this subject, and the study addresses an important, albeit narrowly defined, problem.

 

Study's strengths and limitations.

Strengths:

1. Full access to patient records from a real haemodialysis centre was granted, in compliance with ethical principles (the study was approved by a bioethics committee, and the data were anonymised).
2. A comprehensive set of variables has been compiled, including demographic, clinical and procedural details, along with clearly defined categories of complications and staff responses.
3. The following conclusions are based on current practical findings. The work is related to the literature and refers to other studies (e.g. in the discussion) and is up to date (e.g. the meta-analysis by Yan et al. [18] supports the role of diabetes).

 

Limitations:

1. Retrospective design: potential for data gaps, document heterogeneity, and challenges in establishing causal relationships.
2. It is important to note that results from a single centre cannot be easily generalised to other centres or populations, due to the lack of verification in multiple sites.
3. It is not possible to assess the relative risk of complications in individual subgroups due to the absence of a control group of patients without cannulation failure. For example, it is unclear whether patients with PVD actually have a higher failure rate than others.
4. No multivariate analysis was conducted, for example, the simultaneous impact of several comorbidities was not examined, which could have taken into account the correlations between them.
5. It should be noted that small numbers in some categories (e.g. AVG vs. AVF or rarer complications) may reduce the power of statistical tests and make the results less stable.
6. There are minor issues with the methodology. For example, t-tests are mentioned in the text, but the results are not described, which raises doubts. Furthermore, the repeated introduction of the study objective (lines 377–385 vs. 400–409) suggests minor editorial shortcomings.

 

We expand the Limitations section to explicitly cover retrospective design, single‑center nature, lack of control group, no multivariable analysis, and small cell sizes.

Linguistic quality and structure of the article was improved.

Recommendations for clinical implications were also added.

 

The text is generally linguistically correct and logically organised (introduction, methods, results, discussion, conclusions). The authors use a professional and factual style.

Recommendation

 

The paper addresses a topic that is of significance to nurses and appears to be a well-conducted, albeit limited, analytical study. It provides clear, practical conclusions (with particular attention to patients with vascular or post-stroke diseases). Nevertheless, there are a number of corrections to be made prior to publication, including the removal of repetitions, the clarification of the description of methods and reservations regarding statistical tests, and the possible addition of a multivariate analysis or at least a discussion of the lack of power for certain variables. These may assist in further refining the reception of the article. 

Recommendations for clinical implications were added. Also,

I would like to congratulate the authors on their work and recommend publication of the manuscript after minor corrections.

 

We thank the reviewer for their constructive and encouraging feedback on our manuscript. All suggested modifications have now been implemented, including reducing repetitions, clarifying the description of the methods and statistical procedures, and elaborating on the limitations related to statistical power and the absence of multivariate analysis. Recommendations for clinical implications were added. We hope these revisions adequately address all reviewer’s comments and further improve the clarity and impact of our work.

Reviewer 4 Report

Comments and Suggestions for Authors

Authors of this retrospective study aimed to investigate the variables related to patients and nurses that contribute to unsuccessful vascular access cannulations and the actions taken in response to handle them. Most patients had hypertension and diabetes, with significant comorbidity burdens. They have found out that infiltration and clot formation were the most common complications of cannulation failures and that they were significantly associated with recurrent stroke and peripheral vascular disease but not with  patient  or nurse demographics, such as  staff experience and education. They have concluded, therefore, that recommendations including implementing tailored protocols, providing ongoing nurse education, conducting systematic vascular assessments and holding regular team reviews should be followed in order to improve access outcomes and patient safety.

The study is, in general, interesting, important for clinical practice and well designed, as a retrospective study can be, with its limitations, as acknowledged by the authors. The introduction provides sufficient background and contains several relevant references. The methods are mostly adequately described and conclusions are supported by the results. However, there are some concerns regarding this study that should be addressed, such as:

1. Authors write that "Infiltration emerged as the most common complication, accounting for 61.0% of cases of cannulation failure." It is, therefore, necessary to describe this complication in more detail, such as the most common sites, therapeutic measures etc.
2. Several results are presented twice, in the manuscript and in tables which presents doubling of data presentation that should be avoided.
3. Table 1:      Action: Starting with the existing catheter ........ 10 (4.40%)  -What is the meaning of this? Did patients already have catheters placed or they needed de novo catheter insertion? Please, explain.
4. Table 2 and Discussion, lines 275-279:   "The current study revealed that cannulation failure for hemodialysis has significant relationships with recurrent stroke and peripheral vascular disease, suggesting neurological and vascular impairments as substantial risk factors. No significant associations were observed with hypertension, diabetes, or ESRD, which may indicate that functional vascular changes, rather than metabolic control, have a greater impact on fistula stability"                                        Comment: It does not make sense to consider hypertension and especially ESRD (the study is with dialysis patients!) as comorbidities because they are present in all (100%) of the included patients.
5. There are other important complications of arteriovenous fistulas, such as venous hypertension with swelling (due to central vein stenosis, for example) or aneurysms and pseudoaneurysms formation of vascular access that pose patients at risk for certain complications, such as rupture, bleeding or involvement of the overlying skin, with consequent cannulation difficulty. Authors should explain and discuss whether they encountered these complications as well and how/if they affected cannulation failure.

Author Response

Response to the comments of Reviewer 4

 

Challenges in Hemodialysis: An Analytic Study of Nurses’ Cannulation Failures

 

We would like to sincerely thank the Editor for the time, effort, and careful consideration dedicated to handling our manuscript. We are also grateful to the reviewers for their thoughtful comments and constructive suggestions, which have greatly improved the clarity, rigor, and overall quality of this work.

 

Reviewer 4:

Quality of English Language

( ) The English could be improved to more clearly express the research.
(x ) The English is fine and does not require any improvement.

 

	Yes	Can be improved	Must be improved	NA
Does the introduction provide sufficient background and include all relevant references?	X
Is the research design appropriate?		X
Are the methods adequately described?	X
Are the results clearly presented?			X
Are the conclusions supported by the results?	X
Are all figures and tables clear and well-presented?			X

 

Comments and Suggestions for Authors

 

Authors of this retrospective study aimed to investigate the variables related to patients and nurses that contribute to unsuccessful vascular access cannulations and the actions taken in response to handle them. Most patients had hypertension and diabetes, with significant comorbidity burdens. They have found out that infiltration and clot formation were the most common complications of cannulation failures and that they were significantly associated with recurrent stroke and peripheral vascular disease but not with  patient  or nurse demographics, such as  staff experience and education. They have concluded, therefore, that recommendations including implementing tailored protocols, providing ongoing nurse education, conducting systematic vascular assessments and holding regular team reviews should be followed in order to improve access outcomes and patient safety.

 

The study is, in general, interesting, important for clinical practice and well designed, as a retrospective study can be, with its limitations, as acknowledged by the authors. The introduction provides sufficient background and contains several relevant references. The methods are mostly adequately described and conclusions are supported by the results.

Thank you so much.

However, there are some concerns regarding this study that should be addressed, such as:

1. Authors write that "Infiltration emerged as the most common complication, accounting for 61.0% of cases of cannulation failure." It is, therefore, necessary to describe this complication in more detail, such as the most common sites, therapeutic measures etc.

 

Thank you for this valuable comment. In response, we have expanded the description of infiltration as a complication. Specifically, we now provide additional details on the most common anatomical sites of infiltration, the clinical signs observed, and the therapeutic/nursing measures undertaken. These details have been added to the Discussion sections to enhance the clinical relevance and clarity of our findings regarding cannulation failure.

 

"Infiltration during AV fistula cannulation refers to blood leaking from the vessel into the surrounding tissues when the needle has penetrated the vessel or is no longer fully within its lumen. It is usually linked to the patient's movement or cannula dislocation or movement. With high blood flow and the cannula not well fixed, it may cause infiltration. Moreover, the quality of the vein may increase the risk of infiltration, as seen in cases of multiple venous stenoses. Infiltration most commonly occurs at the arterial or venous needle sites in the cannulated segment of the fistula, especially in areas with tortuous veins, recent cannulation sites, or segments with prior bruising or scarring [22]. Clinically, it presents sudden pain or burning at the needle site, swelling, tense or firm tissue around the access, bruising/hematoma, and often machine alarms from altered pressures or loss of adequate blood flow. Therapeutic measures include stopping the blood pump immediately, clamping and removing or repositioning the needle, applying gentle pressure, and then cold compresses (ice) in the acute phase to limit bleeding and hematoma, elevating the limb, and avoiding re‑cannulation of the infiltrated area for several sessions [23]".

2. Several results are presented twice, in the manuscript and in tables which presents doubling of data presentation that should be avoided.

We thank the reviewer for this observation. We have carefully reviewed the Results section and the tables to minimize redundancy. We believe this approach maintains clarity and supports reader understanding while avoiding unnecessary duplication e.g. Table 1.

Repeated results were also removed from the discussion, for example, “The results of the current study highlight the complex clinical challenges faced by patients undergoing hemodialysis. All participants were diagnosed with ESRD and had hypertension, conditions that often coexist and contribute to vascular compromise. Moreover, the presence of diabetes mellitus in more than two-thirds of the participants further complicates vascular health and healing capacity.”

 

3. Table 1:      Action: Starting with the existing catheter ........ 10 (4.40%)  -What is the meaning of this? Did patients already have catheters placed or they needed de novo catheter insertion? Please, explain.

“When patients start dialysis in an emergency situation, they are inserted with a dialysis catheter, which is used until the fistula becomes mature. Even after an AV fistula becomes mature, cannulation may sometimes fail. According to the hospital policy, the dialysis catheter can only be removed after 6 successful cannulations of the AVF. In this case, the patient in this category (primary access is catheter) still has a dialysis catheter, so dialysis can be continued through the existing catheter for that session, without treatment delay. The fistula is then reassessed, and further actions are taken accordingly. The catheter is usually kept until the fistula has been successfully cannulated and used effectively for several dialysis sessions.”

Added in 3.1. Demographic and Clinical Characteristics, and in the discussion.

 

4. Table 2 and Discussion, lines 275-279:   "The current study revealed that cannulation failure for hemodialysis has significant relationships with recurrent strokes, and peripheral vascular disease, suggesting neurological and vascular impairments as substantial risk factors. No significant associations were observed with hypertension, diabetes, or ESRD, which may indicate that functional vascular changes, rather than metabolic control, have a greater impact on fistula stability"                                       

Comment: It does not make sense to consider hypertension and especially ESRD (the study is with dialysis patients!) as comorbidities because they are present in all (100%) of the included patients.

Completely correct. This was removed from the abstract, from table 2 and the comments (3.2. Comorbidities), from table 3 and the comments (3.4. Associations between cannulation failure incidence and Comorbidities), and from the discussion (first paragraph).

 

5. There are other important complications of arteriovenous fistulas, such as venous hypertension with swelling (due to central vein stenosis, for example) or aneurysms and pseudoaneurysms formation of vascular access that pose patients at risk for certain complications, such as rupture, bleeding or involvement of the overlying skin, with consequent cannulation difficulty.

Authors should explain and discuss whether they encountered these complications as well and how/if they affected cannulation failure.

We tried to  illustrate that in the discussion “Complications of arteriovenous fistulas may include venous hypertension with swelling (often due to central vein stenosis) or aneurysms and pseudoaneurysms formation of vascular access, usually identified by vascular surgeons, that pose patients at risk for certain complications, such as rupture, bleeding, or involvement of the overlying skin, with consequent cannulation difficulty [24]. Other complications of AVF also include thrombosis with access occlusion, outflow or anastomotic stenosis, access-site infection, steal syndrome with distal limb ischemia, high-output cardiac failure in large high-flow fistulas, and hematoma or significant post-cannulation bleeding [25].”

 

 

We thank the reviewer for their constructive and encouraging feedback on our manuscript. All suggested modifications have now been implemented. We hope these revisions adequately address all reviewer’s comments and further improve the clarity and impact of our work.