Ultrasound-Guided Workflow for Peripheral Venous Access Selection, Maintenance, and Dynamic Catheter Adjustment in Adult Hospitalized Patients

Summary

This protocol describes an ultrasound-guided workflow for peripheral venous access selection, closed-loop catheter maintenance, and dynamic adjustment in adult hospitalized patients requiring intravenous infusion therapy.

Abstract

Peripheral venous access is the most frequently performed invasive procedure in hospitalized patients; however, conventional experience-based management is subjective and associated with higher complication rates and lower nursing efficiency. This single-center retrospective before-and-after study evaluated a reproducible ultrasound-guided workflow for peripheral venous access selection, maintenance, and dynamic catheter adjustment. A total of 113 hospitalized patients receiving intravenous infusion therapy between May 1, 2024, and August 31, 2025, were included. The control group (n = 61) received traditional nursing care, whereas the observation group (n = 52) received an ultrasound-guided integrated nursing model incorporating vascular assessment, predefined access-selection criteria, closed-loop maintenance, and protocol-based dynamic adjustment. Outcomes included puncture performance, catheter dwell time and utilization, complications, nursing efficiency, health economic outcomes, and patient satisfaction. Outcome data were extracted from routine clinical records, and blinded outcome assessment was not feasible because group allocation was determined by the implementation period. Baseline characteristics were comparable between groups (P > 0.05). Compared with the control group, the observation group demonstrated a higher access-selection matching rate (86.5%; unadjusted P = 0.026), improved first-attempt puncture success (88.5% vs. 73.8%; unadjusted P = 0.049), lower puncture pain (VAS 1.65 ± 0.84; P < 0.001), longer catheter dwell time (P < 0.001), fewer venous accesses per treatment course (1.04 ± 0.19 vs. 1.64 ± 0.66; P < 0.001), lower overall complication rates (11.5% vs. 29.5%; unadjusted P = 0.020), faster complication detection and management (P ≤ 0.001), reduced daily nursing time (14.73 ± 4.56 vs. 27.64 ± 7.44 min; P < 0.001), lower direct venous access-related medical costs, and improved patient satisfaction, while hospital stay remained unchanged (P = 0.935). These findings indicate that integrating vascular ultrasound throughout the peripheral venous access pathway provides a standardized workflow that improves clinical outcomes, enhances nursing efficiency, and reduces medical risk.

Introduction

Peripheral venous access is the most basic and also the most important invasive route for clinical treatment. Approximately 70% to 80% of hospitalized patients require intravenous infusion therapy, and more than 90% of medication administration procedures are performed through peripheral veins¹. The quality of access management directly affects treatment continuity, patient safety, and nursing efficiency, making it a key component of clinical nursing quality control that should not be overlooked². Traditional peripheral venous access management, however, relies entirely on visual inspection and experiential judgment by nurses. As a result, it is highly subjective and often varies considerably from one individual to another³. Clinical data have shown that, under visual assessment alone, the first-attempt puncture success rate is only 62% to 71%, and in patients who are obese, elderly, edematous, or have poor vascular conditions, this rate falls below 50%⁴. Repeated puncture not only increases patient discomfort but may also cause irreversible vascular injury and compromise subsequent long-term treatment⁵. In addition, the lack of standardized post-procedural maintenance procedures and dynamic assessment mechanisms has kept the incidence of venue-related access-related complications at a persistently high level. This not only increases the economic burden on patients but also adds considerably to the nursing workload⁶.

In recent years, vascular ultrasound has gradually been introduced into clinical nursing practice and has improved puncture success in patients with difficult venous access⁷. At the same time, the full-process management concept of “precise selection - closed-loop maintenance - dynamic adjustment” has also begun to attract attention, and some institutions have attempted to apply it to peripheral venous access management. Even so, this model is still at an exploratory stage and has not yet developed into a mature standardized system. In some reports, for example, the three components were simply combined in parallel, without meaningful integration or effective information flow among them⁸. In others, ultrasound assessment data were used mainly for pre-puncture selection and did not effectively guide subsequent adjustment of maintenance frequency or early warning of complications⁹. In addition, operating procedures vary considerably across institutions, and the lack of unified quality control standards makes published findings difficult to reproduce or generalize¹⁰. Existing studies are also limited by a rather narrow evaluation framework. Most have focused only on clinical safety outcomes such as puncture success and complication rates, while comprehensive assessment of nursing efficiency, health economic benefit, and the experience of both patients and healthcare staff remains insufficient^11,12.

To address these gaps, the present study established a reproducible ultrasound-guided workflow for peripheral venous access selection, maintenance, and dynamic catheter adjustment, built around the integrated nursing process of “precise selection - closed-loop maintenance - dynamic adjustment.” This workflow is intended for adult hospitalized patients receiving inpatient infusion therapy, particularly those with difficult venous access or poor vascular conditions and is designed for use by ultrasound-capable intravenous therapy nurses or vascular access teams in routine inpatient care. This model moves beyond the conventional view that ultrasound is used only for puncture guidance and instead applies ultrasound assessment throughout the entire life cycle of venous access. Objective indicators, including venous diameter, vessel wall thickness, and blood flow velocity, were quantified to formulate standardized criteria for access selection. A closed-loop management mechanism was also developed for early complication identification, graded intervention, and outcome tracking, while the access management strategy was adjusted in real time according to changes in the patient's treatment plan and vascular condition. Systematic evaluation of this workflow may provide practical evidence for standardized and refined management of peripheral venous access, while also carrying clinical implications for reducing nursing risk, improving service quality, and alleviating patient burden.

Protocol

This study was approved by the Medical Ethics Committee of The Fourth Affiliated Hospital of Soochow University (Ethic Code No: 251264). As this was a retrospective analysis, informed consent was waived. The study was conducted in strict accordance with the ethical principles of the Declaration of Helsinki.

1. Personnel and Procedural Preparation

1. Assign the workflow to a specialized intravenous therapy nursing team whose members have completed standardized training and competency assessment. Ensure that each operator is qualified in vascular ultrasound assessment, catheter-to-vessel matching, ultrasound-guided cannulation, phlebitis grading, and protocol-based catheter adjustment.
2. Prepare the ultrasound system listed in the Table of Materials, peripheral intravenous catheters, sterile ultrasound gel, a probe cover, skin antiseptic, transparent dressings, 0.9% sodium chloride solution, fixation materials, and waste containers. Verify that the ultrasound probe, Doppler function, and electronic calipers operate correctly before examining the patient.
   NOTE: Use only catheter gauges for which the manufacturer-reported outer diameter is available; do not infer the catheter outer diameter from the nominal gauge alone.
3. Position the patient supine or seated according to the clinical condition and place the target upper extremity on a stable support with the forearm comfortably extended. Keep the limb relaxed and the intended scanning and cannulation area fully exposed.

2. Ultrasound Assessment and Catheter-to-Vessel Matching

1. Apply ultrasound gel to the target area and place the probe lightly on the skin. Maintain sufficient contact to obtain a clear image without compressing the superficial vein.
2. Scan each candidate vein in the short-axis view to identify the vein, adjacent artery, compressibility, depth, and surrounding tissue. Rotate the probe 90° and use the long-axis view to confirm vessel continuity, intraluminal patency, wall regularity, and an unobstructed puncture path.
3. Quantify the candidate vessel
   1. Freeze a short-axis image when the venous lumen is fully open and measure the internal diameter from inner wall to inner wall at the widest point. Repeat the measurement three times without probe compression and record the mean value.
   2. Measure venous depth vertically from the skin surface to the anterior vessel wall at the same segment. Measure vessel wall thickness three times at the clearest visible wall interface and record the mean value.
   3. Position the Doppler sample volume in the center of the lumen and maintain an insonation angle of ≤60°. Record peak blood-flow velocity from three consecutive stable waveforms and compare the mean value with that of a proximal segment of the same vein or the homologous contralateral vein.
      ​NOTE: Record the anatomical location of the measured segment and use the same limb position, probe pressure, and measurement method during subsequent reassessment.
4. Determine vessel eligibility and catheter suitability.
   1. Exclude any vessel with a mean wall thickness >0.5 mm, intraluminal thrombotic echo, marked stenosis, poor compressibility, or a peak blood-flow velocity reduction >30% relative to the proximal or contralateral reference segment. From the remaining vessels, select a straight and patent segment located away from a joint.
   2. Calculate the catheter-to-vessel ratio as follows: catheter-to-vessel ratio (%) = catheter outer diameter (mm)/mean internal venous diameter (mm) ×100. Record the measured venous diameter, catheter outer diameter, and calculated ratio before cannulation.
   3. Select the smallest catheter gauge compatible with the prescribed infusion and use the selected vessel only when the catheter-to-vessel ratio is ≤45%. When the ratio exceeds 45%, select a catheter with a smaller outer diameter or choose another eligible vessel; use an alternative vascular access device when neither option is clinically appropriate.

3. Ultrasound-Guided Cannulation and Postprocedural Handling

CAUTION: Treat blood and all blood-contaminated materials as biological hazards, needles and stylets as percutaneous sharps hazards, and alcohol- or chlorhexidine-based skin antiseptics as flammable and irritant chemical hazards. Wear disposable nitrile gloves, a fluid-resistant long-sleeved gown, a surgical mask, and goggles or a face shield during skin preparation, cannulation, catheter removal, and contaminated-waste handling; keep antiseptics away from ignition sources and allow the prepared skin to dry completely before puncture.

1. Disinfect the puncture area according to the institutional standard and allow the antiseptic to dry completely. Perform ultrasound-guided cannulation using either the short-axis out-of-plane or long-axis in-plane technique while continuously confirming the position of the needle tip relative to the target vein.
2. Confirm intravascular catheter placement, secure the catheter, and cover the site with transparent dressing. Document the selected vein, catheter gauge and outer diameter, venous diameter, catheter-to-vessel ratio, ultrasound measurements, number of puncture attempts, procedure time, and puncture pain score.
   CAUTION: Do not recap, bend, break, or manually detach used needles or stylets; discard them immediately into a closable, leak-resistant, puncture-resistant sharps container. Place used catheters, blood-contaminated gauze, dressings, gloves, and probe covers in a labeled biohazard-waste container; collect unused or spilled antiseptic and chemically contaminated absorbent materials in the designated chemical-waste container, place only uncontaminated packaging in general waste, and clean and disinfect reusable ultrasound probes and cables after each patient with a manufacturer-compatible hospital-grade disinfectant.

4. Daily Reassessment and Dynamic Catheter Adjustment

1. Have an ultrasound-qualified intravenous therapy nurse perform and document the daily ultrasound reassessment at 8:00 a.m. Have the bedside nurse inspect the catheter site during each shift and request immediate reassessment when pain, erythema, swelling, leakage, resistance to flushing, or another catheter-related abnormality is observed.
2. Reassess catheter position, venous wall thickness, peak blood-flow velocity, compressibility, puncture-site appearance, patient-reported symptoms, and dressing integrity at the previously documented vascular segment. Compare the measurements with the baseline and reference values, and limit routine catheter dwell time to 96 h unless an earlier adjustment criterion is met.
3. Apply the catheter-adjustment criteria.
   1. Repeat the ultrasound measurement after releasing probe pressure when an isolated ultrasound abnormality is detected. Stop using the catheter and change the site before the next infusion when venous wall thickness exceeds 0.5 mm or peak blood-flow velocity decreases by >30% relative to the baseline or reference value.
   2. Remove the catheter immediately when grade ≥2 phlebitis, infiltration or extravasation, persistent leakage, unresolved catheter occlusion, suspected thrombosis, or suspected catheter-related infection is identified. Replace only the dressing when its integrity has failed but catheter stability, puncture-site sterility, and vascular findings remain acceptable.
4. Grade and manage phlebitis.
   1. Assess and document the phlebitis grade during each scheduled or symptom-triggered review. Reassess and record the grade after every intervention.
      NOTE: Define grade 0 as no signs or symptoms; grade 1 as access-site erythema with or without pain; grade 2 as access-site pain accompanied by erythema and/or edema; grade 3 as pain, erythema and/or edema accompanied by streak formation and a palpable venous cord; and grade 4 as grade 3 findings accompanied by a palpable venous cord >2.5 cm and/or purulent drainage.
   2. For grade 1 phlebitis, pause the infusion, provide local care, and repeat the clinical and ultrasound assessment. For grade ≥2 phlebitis, remove the catheter, establish access at another site when infusion must continue, provide symptomatic treatment according to institutional policy, and document follow-up until resolution. Details are shown in Table 1.

5. Outcome Assessment and Statistical Analysis

1. Access selection matching and puncture-related indicators
   1. Access selection matching was defined as the selection of a patent and compressible vessel without venous wall thickness >0.5 mm, local thrombosis, marked stenosis, or a >30% reduction in peak blood-flow velocity, together with a catheter-to-vessel ratio ≤45%, calculated as the manufacturer-reported catheter outer diameter divided by the mean internal venous diameter ×100.
   2. A selection was classified as unmatched when any criterion was not met or when the catheter outer diameter or venous diameter required to calculate the ratio was not documented. Selections that failed to meet any of these criteria, or lacked sufficient documentation for adjudication, were classified as unmatched.
   3. Retrospective adjudication was performed using the original nursing and ultrasound records; complete blinding to group allocation was not feasible because ultrasound documentation was part of the intervention.
   4. Puncture-related indicators included the first-attempt puncture success rate (defined as the percentage of successful first-attempt punctures among all puncture procedures), the incidence of second or subsequent puncture attempts, mean puncture procedure time (from preparation of materials to successful puncture and fixation), and patient pain score during puncture, which was assessed using the visual analog scale (VAS)¹³, where 0 indicates no pain, and 10 indicates severe pain.
2. Indicators of catheter dwell time and utilization included the actual dwell time of each venous access, the rates of planned and unplanned catheter removal, and the total number of venous accesses required during a single treatment course.
3. Complication-related indicators included the overall complication rate; the incidence of each specific complication, including phlebitis, leakage/extravasation, catheter occlusion, thrombosis, and catheter-related infection; time to complication occurrence (from successful puncture to confirmed complication); time to complication detection (from complication onset to nurse recognition); mean time required for complication management; the number of additional punctures caused by complications; and the outcomes of severe complications.
4. Nursing efficiency indicators were calculated from the nursing scheduling system and nurses' work records and included mean daily venous nursing time per patient (covering puncture, maintenance, complication management, and handover time), the mean number of venous accesses managed by each nurse per shift, the additional nursing workload caused by unplanned catheter removal, the incidence of venous access-related nursing errors, the mean daily overtime attributable to venous access problems, and the mean handover time for venous access at shift change.
5. Health economic indicators included the direct medical cost related to venous access per patient from the hospital perspective, including indwelling catheters and related consumables, medications, and examinations used for complication management, and nursing labor costs calculated according to recorded venous-access nursing time and the local hourly wage standard for nursing staff. Fixed overhead costs, equipment depreciation, patient transportation costs, productivity loss, and other indirect societal costs were not included; therefore, the economic analysis was limited to direct venous access-related hospital costs.
6. Patient satisfaction was evaluated on the day of discharge using the hospital's standardized nursing service satisfaction questionnaire, which covered four dimensions: overall satisfaction, puncture technique, pain management, and service attitude. The questionnaire was administered as part of the routine discharge nursing-quality survey; however, because the retrospective records did not allow confirmation that all questionnaires were collected by personnel independent of bedside catheter care, satisfaction outcomes were interpreted as supportive patient-reported indicators.
7. Statistical Analysis
   1. Data conforming to a normal distribution were expressed as mean ± standard deviation (‾χ ± s), and intergroup comparisons were performed using the independent-samples t test; however, for complication-process variables analyzed only among patients who developed complications, Mann-Whitney U tests were used, and values were presented as median [interquartile range] because of the small subgroup sizes.
   2. Unless otherwise specified, all between-group analyses were based on the full analysis cohort of 61 patients in the control group and 52 patients in the observation group.
   3. Analyses of time to complication detection, time required for complication management, additional punctures caused by complications, and effective complication management were restricted to patients who developed at least one venous access-related complication, comprising 18 patients in the control group and 6 patients in the observation group.
   4. Data not conforming to a normal distribution were expressed as median and interquartile range [M (P25, P75)] and were compared using the Mann-Whitney U test. Categorical variables were expressed as numbers and percentages (n, %) and were compared using the χ² test or Fisher's exact test. Ordinal data were compared using the Mann-Whitney U test.
   5. All tests were two-sided, and P < 0.05 was considered statistically significant. Because this exploratory evaluation included multiple clinical, process, and economic endpoints, P values were reported as unadjusted; no formal multiplicity correction was applied, and borderline findings were interpreted cautiously.
   6. No formal a priori sample size calculation was conducted because all eligible patients treated during the predefined pre-implementation and post-implementation periods were included.
   7. A descriptive post-hoc power assessment based on the observed first-attempt puncture success rates of 73.8% and 88.5% indicated approximately 52.6% power at a two-sided alpha level of 0.05; therefore, the study was considered exploratory, and secondary or subgroup outcomes were interpreted with caution.

Results

Study Design and Participants

For evaluation of this workflow, this study used a single-center retrospective before-and-after design based on a hospital-level nursing practice change. Consecutive eligible patients treated during the predefined pre-implementation and post-implementation periods were included, and outcome data were extracted from routine clinical, nursing, and hospital information systems. Hospitalized patients who received intravenous infusion therapy at our hospital between May 1, 2024, and August 31, 2025, were screened through the hospital electronic medical record system, nursing information system, and hospital information management system.

Grouping was based on when the nursing model was formally implemented at our hospital, because group allocation was determined by calendar period, seasonal variation, secular trends, staffing changes, learning-curve effects, and concurrent quality-improvement activities could not be fully excluded as potential sources of residual confounding. Patients admitted between May 1, 2024, and October 31, 2024, received traditional peripheral venous access nursing care and were assigned to the control group. After the hospital fully implemented the integrated nursing model based on vascular ultrasound assessment on November 1, 2024, all subsequently admitted patients who received this new management strategy were assigned to the observation group.

To reduce selection bias, consecutive eligible patients during the predefined pre-implementation and post-implementation periods were screened using the same inclusion and exclusion criteria. Five cases were excluded by complete-case analysis because key clinical data were missing, including incomplete records of puncture time, complications, or outcome data. Ultimately, 113 patients were included in the final analysis, including 61 in the control group and 52 in the observation group. Follow-up began at the first establishment of peripheral venous access during the current hospitalization and ended when intravenous infusion therapy was completed, or the catheter was removed at discharge; no patient was lost before this prespecified follow-up endpoint.

The inclusion criteria were as follows: age 18–85 years; first establishment of upper-extremity peripheral venous access during the current hospitalization; an expected infusion course of ≥3 days and an actual infusion duration of ≥2 days; clear consciousness and ability to cooperate with treatment and nursing care; and complete, traceable clinical diagnosis, treatment, and nursing records.

The exclusion criteria were as follows: skin injury, infection, trauma, or congenital malformation in the upper extremities; a history of deep or superficial venous thrombosis in the upper extremities; severe coagulation abnormalities (INR >2.5 or platelet count <50 × 10⁹/L); receipt of systemic anticoagulation or thrombolytic therapy during the study period; severe heart, liver, or renal failure (NYHA class III-IV cardiac function, Child-Pugh class C, or requiring dialysis); psychiatric disease or cognitive impairment that prevented cooperation with treatment; transfer to another department, discharge against medical advice, or death during hospitalization; and missing key clinical or nursing records.

Use the conventional peripheral venous access nursing procedure for patients managed before implementation of the ultrasound-guided workflow. Assess vascular conditions by visual inspection and finger palpation before puncture, select the puncture site and catheter size according to the nurse's clinical experience, and perform routine blind peripheral venous cannulation according to the institutional intravenous-therapy nursing standard. After cannulation, assess the puncture site once every morning at 8:00 a.m. for redness, swelling, bleeding, exudation, leakage, pain, and patient-reported discomfort. Flush and lock the catheter with 0.9% sodium chloride injection after infusion, replace transparent dressings every 7 days, and replace the dressing earlier if bleeding, exudation, edge lifting, contamination, or excessive sweating compromises dressing integrity. Manage phlebitis, infiltration, catheter occlusion, or other catheter-related complications according to the institutional standard. Remove the catheter and perform repuncture when continued infusion is required and catheter retention is no longer clinically appropriate.

Comparison of Baseline Clinical Characteristics Between the Two Groups

There were no statistically significant differences between the two groups in any baseline dimension, including demographic characteristics, spectrum of underlying diseases, treatment-related indicators, laboratory findings, and concomitant medication use (P > 0.05). The two groups were therefore well balanced, providing a reliable basis for subsequent intergroup comparisons (Table 2).

Analysis of Vascular Ultrasound Assessment Parameters and Access Selection Matching

No significant differences were found between the two groups in the basic anatomical parameters of the three major veins in the upper extremity (P > 0.05). However, the standardized selection process based on quantitative ultrasound indicators reduced the arbitrariness associated with traditional experience-based judgment. The access selection matching rate in the observation group reached 86.5%, which was higher than that in the control group by Fisher's exact test (unadjusted P = 0.026) (Table 3).

Comparison of Core Puncture-Related Indicators

The observation group achieved a first-attempt puncture success rate of 88.5%, compared with 73.8% in the control group (unadjusted P = 0.049). The mean puncture procedure time was also shorter, and the VAS pain score during puncture decreased to 1.65 ± 0.84 (P < 0.001). In the subgroup analysis by preprocedural vascular classification, first-attempt success rates tended to be higher in the observation group across grade I, II, and III veins, but none of these subgroup comparisons reached statistical significance after recalculation from the raw dataset, and these results should be interpreted descriptively because of the small subgroup sizes (Table 4).

Analysis of Venous Access Dwell Time and Overall Utilization

Mean dwell time of venous access was longer in the observation group than in the control group (P < 0.001). Correspondingly, the number of venous accesses required for a single treatment course decreased from 1.64 ± 0.66 in the control group to 1.04 ± 0.19 in the observation group (P < 0.001). The proportion of access idle time also declined (P < 0.001), indicating better resource utilization (Table 5).

Analysis of the Incidence and Severity of Venous Access-Related Complications

The full-process protection system established under the integrated nursing model reduced the overall risk of venous access-related complications. Specifically, the total complication rate in the observation group was 11.5%, lower than the 29.5% recorded in the control group (unadjusted P = 0.020), although this result should be interpreted cautiously because no multiplicity correction was applied. In addition, no cases of thrombosis or catheter occlusion occurred in the observation group, although this finding may be partly related to the relatively small sample size of the present study (Table 6).

Comparison of Complication Management Process and Outcomes

Benefiting from the closed-loop management mechanism of “assessment - intervention - reassessment,” the observation group showed better performance in complication recognition and management. Among patients who developed at least one complication, including 18 patients in the control group and 6 patients in the observation group, the time to complication detection was shorter in the observation group than in the control group [5.50 (4.25, 6.00) h vs. 8.00 (8.00, 9.75) h; Mann–Whitney U test, P = 0.001], and the time required for complication management was also reduced [21.00 (18.25, 23.75) min vs. 37.00 (32.50, 40.50) min; P < 0.001]. However, all complications were resolved after treatment in both groups, and no significant difference was found in the number of additional punctures caused by complications [0.50 (0.00, 1.00) vs. 1.00 (1.00, 1.75); P = 0.110] (Table 7).

Analysis of Nursing Efficiency and Labor Costs

The mean daily venous nursing time per patient decreased from 27.64 ± 7.44 min to 14.73 ± 4.56 min (P < 0.001), allowing each nurse to manage more venous accesses per shift (P < 0.001). Overtime attributable to venous access problems and handover time at shift change were also reduced accordingly (P < 0.001).

Analysis of Health Economic Benefits

Health economic evaluation showed that the direct medical cost related to venous access per patient was lower in the observation group than in the control group (P < 0.05), whereas nursing labor costs did not differ significantly despite the reduction in recorded venous nursing time. Further analysis of the cost components suggested that the savings mainly came from reduced complication treatment costs and lower expenditure on indwelling catheter consumables. In addition, the length of hospital stay did not differ significantly between the two groups (P = 0.935) (Figure 1).

Evaluation of Patient Satisfaction and Nursing Staff Experience

Both patients and healthcare staff showed a high level of acceptance of the integrated nursing model. The overall satisfaction score of patients in the observation group was higher than that in the control group, with the most pronounced improvements seen in puncture technique and pain management (P < 0.05) (Figure 2).

Interpretation of Representative Results

Taken together, these representative results indicate successful implementation of the ultrasound-guided workflow when improved access performance is accompanied by fewer catheter-related complications, shorter nursing time, lower direct venous access-related medical costs without prolongation of hospital stay, and better patient-reported satisfaction, as shown in Figure 1, Figure 2. When applying this protocol, readers should interpret concordant improvements in workflow efficiency, cost control, and patient-centered outcomes as a representative successful result; in contrast, persistently high complication-management workload, unchanged or increased access-related costs, no improvement in puncture technique or pain-management satisfaction, or any apparent cost reduction accompanied by longer hospitalization should be considered suboptimal and should prompt review of ultrasound measurement accuracy, catheter-to-vessel matching, maintenance adherence, and dynamic adjustment criteria.

The raw data used in this study has been uploaded as Supplementary File 1.

Figure 1. Comparison of health economic outcomes between the control group and the observation group. (A) Direct medical costs related to peripheral venous access per patient. (B) Consumable costs related to peripheral venous access. (C) Costs of complication management. (D) Nursing labor costs. (E) Length of hospital stay. Data are presented as mean ± standard deviation (SD). *P < 0.05, ns P > 0.05. Please click here to view a larger version of this figure.

Figure 2. Comparison of patient satisfaction outcomes between the control group and the observation group. (A) Overall satisfaction score. (B) Puncture technique satisfaction score. (C) Pain management satisfaction score. (D) Service attitude satisfaction score. Data are presented as mean ± standard deviation (SD). *P < 0.05. Please click here to view a larger version of this figure.

Version

They received a 2-week standardized training program focused on ultrasound anatomy, venous diameter and wall-thickness measurement, blood-flow velocity assessment, catheter-to-vessel matching, complication grading, and protocol-based site adjustment, and they were allowed to perform the procedures independently only after passing competency assessment based on supervised scanning and catheterization.

All patients underwent a systematic ultrasound assessment of upper-extremity vessels within 30 min before puncture, and all assessment data were recorded in the Venous Access Ultrasound Assessment Form. A portable color Doppler ultrasound system (Philips Healthcare, Eindhoven, Netherlands; model CX50; linear-array probe frequency 5–12 MHz) was used. Patients were placed in the supine position, with the upper limb abducted to 30° and kept naturally relaxed. After uniform application of medical ultrasound coupling gel (Tianjin Yajie Medical Materials Co., Ltd., Tianjin, China; batch No. 20240428), the cephalic vein, basilic vein, and median cubital vein were scanned sequentially along their entire course from the wrist to 5 cm above the antecubital fossa. The transverse venous diameter, venous wall thickness, and peak systolic blood flow velocity were measured and recorded at a depth of 1–2 cm beneath the skin surface. At the same time, vascular alignment, branch variation, valvular function, and the presence or absence of thrombosis or stenosis within the lumen were evaluated. Standardized access selection was then performed according to the ultrasound findings: a 20G disposable peripheral intravenous catheter (Becton Dickinson, Franklin Lakes, NJ, USA; model Intima II) was selected when the venous diameter was ≥3.0 mm and was used for rapid infusion, blood transfusion, and infusion of irritant agents such as chemotherapeutic drugs and vasoactive medications; a 22G catheter was selected when the diameter was 2.0–2.9 mm and was used for routine infusion therapy; and a 24G catheter was selected when the diameter was 1.5–1.9 mm and was considered suitable for elderly patients and those with poor vascular conditions.

Real-time ultrasound-guided in-plane puncture was performed. The needle was inserted at an angle of 15°–30° to the skin, with the needle tip clearly visualized on the ultrasound image. Once blood return was observed, the insertion angle was lowered and the needle was advanced a further 1–2 mm, after which the outer cannula was advanced into the vessel and the stylet was withdrawn. After confirming smooth blood return, the catheter was secured without tension using a sterile transparent dressing (3M Healthcare, St. Paul, MN, USA; model Tegaderm 1624W). The edges of the dressing were pressed firmly into place, and the date and time of puncture as well as the operator’s ID number were clearly marked in the lower right corner. The procedure time for each case was controlled within 15 min.

From successful puncture to catheter removal, a closed-loop management system of “daily dual assessment - graded intervention - outcome tracking” was implemented throughout, and all assessment and intervention records were entered into the nursing information system in real time. Standardized maintenance procedures were strictly followed in daily practice. Before each infusion, the catheter was flushed with 5 mL of 0.9% sodium chloride injection using a pulsatile technique, and infusion was started only after patency had been confirmed. After infusion, the catheter was flushed with 10 mL of 0.9% sodium chloride injection using the same pulsatile technique; when 0.5–1 mL remained, the catheter was clamped while injection continued to achieve positive-pressure locking. Transparent dressings were routinely replaced every 7 days and were changed earlier when bleeding, exudation, edge lifting, contamination, or excessive sweating compromised dressing integrity. The heparin cap was replaced every 3 days and was changed immediately if blood residue or contamination was present. At 8:00 a.m. each day, both clinical assessment and ultrasound assessment were performed. Clinical assessment focused on redness, swelling, pain, bleeding, exudation at the puncture site, and catheter dislodgement or kinking. Ultrasound assessment focused on venous wall thickening, luminal stenosis, reduced blood flow velocity, and microthrombus formation. All complications were diagnosed and graded according to the 2021 INS standards. Once identified, the corresponding management protocol was initiated immediately: grade I phlebitis was treated with a warm moist compress containing 50% magnesium sulfate, three times daily for 20 min each time; for grade II phlebitis or above, the catheter was removed immediately and topical mucopolysaccharide polysulfate cream was applied locally. A dedicated complication registry was maintained for all complications, documenting the time of occurrence, grade, management measures, and treatment response, with reassessment performed every 6 h until complete resolution.

After comprehensive assessment at 8:00 a.m. each day, the management strategy was adjusted in real time according to the patient’s treatment plan, vascular status, and access function. When the treatment regimen changed, for example from routine infusion to the administration of chemotherapeutic agents, vasoactive drugs, or hyperosmolar nutrient solutions, ultrasound reassessment of the vessels was performed immediately. If the internal diameter of the existing access was <2.5 mm, replacement with a 20G catheter was planned in advance. If ultrasound showed early signs of vascular injury, such as venous wall thickening >0.5 mm or a >30% reduction in blood flow velocity, the puncture site was electively changed within 24 h even in the absence of clinical symptoms. If access function remained adequate and treatment still needed to continue, routine dwell time was capped at 96 h unless earlier removal was clinically indicated. In cases of catheter occlusion, severe infiltration, or infection, the catheter was removed immediately and a new access was established.

Table 1: Components and operational procedures of the vascular ultrasound-guided integrated nursing workflow for peripheral venous access. This descriptive table summarizes team responsibility and training, precise preprocedural selection, standardized intra-procedural operation, closed-loop postprocedural maintenance, and dynamic adjustment throughout the process; no statistical comparison is included.

Variable	Control group (n = 61)	Observation group (n = 52)	t/χ² value	P value
Age (years)	57.0 ± 10.7	59.6 ± 9.1	1.363	0.176
Sex (male/female)	32/29	30/22	0.311	0.577
BMI (kg/m²)	23.2 ± 2.9	23.8 ± 3.0	1.058	0.292
Marital status (married/unmarried/divorced/widowed)	48/5/4/4	45/3/3/1	1.834	0.608
Smoking history	19 (31.1)	14 (26.9)	0.242	0.623
Alcohol consumption history	15 (24.6)	17 (32.7)	0.908	0.341
Underlying diseases
Diabetes mellitus	17 (27.9)	14 (26.9)	0.013	0.911
Hypertension	22 (36.1)	23 (44.2)	0.781	0.377
Coronary heart disease	9 (14.8)	6 (11.5)	0.252	0.616
Infusion course (d)	4.9 ± 1.3	4.7 ± 1.0	1.051	0.295
Mean daily infusion volume (mL)	1260.5 ± 347.9	1195.5 ± 332.6	1.01	0.315
Preprocedural visual vein grade (grade I/II/III)	19/27/15	21/20/11	1.048	0.592
History of venipuncture in the previous year (times)	6.6 ± 2.2	6.5 ± 2.2	0.383	0.703
Use of anticoagulants	9 (14.8)	6 (11.5)	0.252	0.616
Use of vasoactive drugs	11 (18.0)	13 (25.0)	0.815	0.367

Table 2: Comparison of baseline clinical characteristics between the control group and the observation group. Continuous variables, including age, body mass index (BMI), infusion course, mean daily infusion volume, and history of venipuncture in the previous year, are presented as mean ± standard deviation (SD), whereas categorical variables are presented as n (%), ratios, or category distributions, as appropriate. P values indicate between-group comparisons using the independent-samples t test, χ² test, or Fisher’s exact test, as appropriate.

Variable	Control group (n = 61)	Observation group (n = 52)	t/χ² value	P value
Cephalic vein diameter (mm)	2.32 ± 0.41	2.45 ± 0.38	1.68	0.096
Basilic vein diameter (mm)	2.71 ± 0.56	2.68 ± 0.49	0.303	0.762
Median cubital vein diameter (mm)	3.16 ± 0.70	3.18 ± 0.67	0.179	0.858
Venous wall thickness (mm)	0.44 ± 0.08	0.43 ± 0.07	0.761	0.448
Peak blood flow velocity (cm/s)	12.46 ± 3.19	13.42 ± 3.20	1.58	0.117
Access selection matching rate	41 (67.2)	45 (86.5)	Fisher’s exact test	0.026

Table 3: Comparison of vascular ultrasound assessment parameters and access selection matching between the control group and the observation group. Cephalic vein diameter, basilic vein diameter, median cubital vein diameter, venous wall thickness, and peak blood flow velocity are presented as mean ± SD, whereas access selection matching rate is presented as n (%). P values indicate between-group comparisons using the independent-samples t test or Fisher’s exact test, as appropriate.

Variable	Control group (n = 61)	Observation group (n = 52)	Test statistic	P value
First-attempt puncture success rate	45 (73.8)	46 (88.5)	χ² = 3.864	0.049
Mean puncture procedure time (min)	6.69 ± 2.21	3.79 ± 1.14	t = 8.535	<0.001
VAS score during puncture	2.46 ± 1.30	1.65 ± 0.84	t = 3.841	<0.001
First-attempt puncture success among grade I veins	15/19 (78.9)	18/21 (85.7)	Fisher’s exact test	0.689
First-attempt puncture success among grade II veins	19/27 (70.4)	18/20 (90.0)	Fisher’s exact test	0.154
First-attempt puncture success among grade III veins	11/15 (73.3)	10/11 (90.9)	Fisher’s exact test	0.356

Table 4: Comparison of core puncture-related outcomes between the control group and the observation group. Mean puncture procedure time and visual analog scale (VAS) score during puncture are presented as mean ± SD, first-attempt puncture success rate is presented as n (%), and subgroup first-attempt success by preprocedural vascular grade is presented as successful punctures/total punctures (%). P values indicate between-group comparisons using the independent-samples t test, χ² test, or Fisher’s exact test, as appropriate.

Variable	Control group (n = 61)	Observation group (n = 52)	t/χ² value	P value
Mean dwell time (h)	53.21 ± 17.45	73.50 ± 16.89	6.251	<0.001
Unplanned catheter removal rate	15 (24.6)	7 (13.5)	2.217	0.137
Number of accesses required for a single treatment course	1.64 ± 0.66	1.04 ± 0.19	6.34	<0.001
Proportion of access idle time	17.47 ± 4.90	8.18 ± 2.95	11.943	<0.001

Table 5: Comparison of venous access dwell time and overall utilization between the control group and the observation group. Mean dwell time, number of accesses required for a single treatment course, and proportion of access idle time are presented as mean ± SD, whereas unplanned catheter removal rate is presented as n (%). P values indicate between-group comparisons using the independent-samples t test or χ² test, as appropriate.

Variable	Control group (n = 61)	Observation group (n = 52)	t/χ² value	P value
Phlebitis incidence	7 (11.5)	2 (3.8)
Infiltration/extravasation	4 (6.6)	2 (3.8)
Catheter occlusion	2 (3.3)	0 (0.0)
Thrombosis	2 (3.3)	0 (0.0)
Catheter-related infection	3 (4.9)	2 (3.8)
Overall incidence	18 (29.5)	6 (11.5)	5.419	0.02

Table 6: Comparison of venous access-related complication rates between the control group and the observation group. Phlebitis, infiltration/extravasation, catheter occlusion, thrombosis, catheter-related infection, and overall complication incidence are presented as n (%). The statistical comparison shown in the table refers to the overall complication incidence, and the P value is unadjusted.

Variable	Control group (n = 18)	Observation group (n = 6)	Test statistic	P value
Time to complication detection (h)	8.00 [8.00, 9.75]	5.50 [4.25, 6.00]	U = 102.000	0.001
Time required for complication management (min)	37.00 [32.50, 40.50]	21.00 [18.25, 23.75]	U = 106.500	<0.001
Effective management rate of complications	18 (100.0)	6 (100.0)	Fisher’s exact test	>0.999
Number of additional punctures caused by complications	1.00 [1.00, 1.75]	0.50 [0.00, 1.00]	U = 76.500	0.11

Table 7: Comparison of complication management processes and outcomes among patients who developed at least one venous access-related complication, including 18 patients in the control group and 6 patients in the observation group. Time to complication detection, time required for complication management, and the number of additional punctures caused by complications are presented as median [interquartile range, IQR], whereas the effective complication management rate is presented as n (%). P values indicate between-group comparisons using the Mann–Whitney U test or Fisher’s exact test, as appropriate.

Supplementary File 1: Raw dataPlease click here to download this file.

Discussion

This single-center retrospective before-and-after study explored the clinical value of an integrated nursing model of “precise selection - closed-loop maintenance - dynamic adjustment” for peripheral venous access based on vascular ultrasound assessment. The findings showed that this model offered clear advantages in improving access management quality, reducing medical risk, optimizing nursing processes, and controlling healthcare costs, thereby providing new practical evidence for the standardized management of peripheral venous access. Successful implementation of this workflow depends on several procedural steps that should be performed consistently rather than selectively. These include standardized pre-puncture ultrasound assessment of venous diameter, depth, wall thickness, and blood flow velocity; predefined access-selection criteria to avoid catheter-vessel mismatch or vessels with early structural abnormality; scheduled post-cannulation reassessment of catheter position, blood flow, puncture-site condition, and dressing integrity; and protocol-based catheter adjustment when venous wall thickening, reduced blood flow velocity, persistent pain, leakage, dressing failure, or suspected early phlebitis is identified.

Quantitative vascular ultrasound assessment fundamentally reduced the subjectivity inherent in access selection under the traditional model. Conventional access selection depends largely on nurses' individual experience and lacks unified objective standards, resulting in substantial inter-operator variation in judgments of the same vessel. This, in turn, is one of the main reasons for inappropriate device selection^14,15. In the present study, a standardized selection system based on ultrasound-derived parameters converted experience-dependent judgment into a reproducible, objective decision-making process. This approach helped reduce, at the outset, vascular injury caused by a mismatch between catheter size and vessel characteristics. This finding is supported by several previous studies. For example, some reports have shown that ultrasound-based objective assessment can improve the accuracy of access selection by 20% to 30%, particularly in patients such as those who are obese or elderly, whose vascular condition is difficult to evaluate by visual inspection alone^16,17. The combination of accurate preprocedural selection and real-time ultrasound guidance during puncture likely explains the overall improvement in puncture performance¹⁸. Ultrasound guidance allows real-time tracking of the needle tip within the vessel, thereby avoiding repeated probing and mechanical injury to the vessel wall during blind puncture, while an appropriately matched catheter further reduces puncture difficulty and minimizes irritation to the vascular endothelium. This mechanism has been supported by a growing body of basic and clinical research, showing that ultrasound-guided puncture can reduce endothelial cell shedding and the release of inflammatory mediators, thereby lowering the risk of puncture-related complications^19,20. It is worth noting that some studies applied ultrasound guidance alone without combining it with precise preprocedural selection, and the improvement in puncture success rate in those studies was clearly less pronounced than that observed here. This suggests that the synergy between preprocedural selection and intraoperative guidance is an important prerequisite for maximizing the intervention effect²¹.

The establishment of a full-process closed-loop management system was another key factor underlying the reduction in complication risk and the prolongation of access lifespan. In most previous studies, ultrasound was mainly used as a puncture aid, while postprocedural maintenance and dynamic adjustment received limited attention; accordingly, the effect on complication prevention was often unsatisfactory^22,23. In this study, ultrasound assessment was extended to the entire life cycle of access. Through daily ultrasound scanning, subclinical signs of injury, such as venous wall thickening and reduced blood flow velocity, could be identified early, allowing timely intervention before obvious clinical symptoms emerged and thereby interrupting the progression of complications^24,25. At the same time, standardized maintenance procedures and a graded management mechanism further improved the efficiency of complication handling and reduced the adverse effect of complications on access longevity. When this workflow is implemented in different clinical settings, several practical adjustments may be required without changing its core logic. In wards with limited ultrasound resources, priority may be given to patients with difficult venous access, edema, obesity, advanced age, repeated puncture history, irritant infusions, or an expected infusion course of several days; in high-throughput settings, a brief screening scan may be followed by full quantitative assessment only when poor vascular conditions are identified. Several predictable failure points should be addressed systematically. When vein visualization is poor, operators should reduce probe pressure, reposition the limb, adjust probe orientation and imaging depth, compare proximal and contralateral segments, and select an alternative vessel rather than repeatedly puncturing a marginal vein. When the measured venous diameter appears inconsistent with vessel appearance or varies substantially between repeated measurements, the operator should return to the short-axis view, confirm that the lumen is fully open, release external compression, repeat three inner-wall-to-inner-wall measurements at the same segment, and use the mean value before calculating catheter suitability. When the catheter-to-vessel ratio exceeds the predefined threshold, the operator should select a catheter with a smaller outer diameter or choose another eligible vessel rather than proceeding with a mismatched catheter. Finally, if a scheduled daily reassessment is missed or documentation does not show whether wall thickness, blood-flow velocity, pain, leakage, and dressing integrity were evaluated, catheter use should not continue automatically; the responsible intravenous therapy nurse should complete and document the reassessment before the next infusion, while periodic checklist audits and escalation of overdue assessments may help prevent repeated omission. Phased training, competency assessment, standardized documentation forms, and regular review of measurement consistency, catheter-to-vessel matching, and reassessment adherence may therefore help maintain protocol fidelity while allowing adaptation to local staffing and equipment conditions.

The improvement in nursing efficiency and the gains in health economic outcomes was, in essence, the result of overall workflow optimization. Some have argued that ultrasound assessment may increase the nursing workload²⁶, but the results of the present study do not support this view. One likely reason is that such studies often counted only the time cost of ultrasound assessment itself, while overlooking the considerable labor saved later through reductions in complication management, unplanned catheter removal, and repeated puncture. The present findings suggest that the time invested upfront in ultrasound assessment can be offset by the reduction in subsequent ineffective nursing work, ultimately leading to an overall improvement in nursing efficiency; however, this released nursing time did not translate into a statistically significant reduction in calculated nursing labor costs, probably because ward staffing costs were largely fixed and the time saved was reallocated to other clinical tasks rather than immediately reducing payroll expenditure. From a health economic perspective, the lower complication rate and longer access lifespan directly reduced material consumption and the costs of complication treatment, while the shorter hospital stays further decreased overall medical expenditure. This conclusion is consistent with the findings of several health economic studies^27,28.

Nevertheless, this study had several important limitations. First, the before-and-after design used historical controls, and the two groups were enrolled during different calendar periods with unequal durations; therefore, seasonal variation in case-mix, background infection-control conditions, staffing levels, secular trends, undocumented co-interventions, and learning-curve effects after protocol implementation could not be fully excluded. Because the retrospective dataset did not include month-by-month staffing, co-intervention, or admission-date variables suitable for interrupted time-series or propensity-score adjustment, these temporal factors were handled as residual confounding and should be considered when interpreting the results. Second, the final sample size provided limited statistical power for several secondary endpoints, especially complication-process analyses involving only patients who developed complications; therefore, non-significant findings, including additional punctures caused by complications and unplanned catheter removal, should not be interpreted as evidence of no effect. Third, performance bias and recording bias could not be fully excluded because bedside nurses participated in routine care and documentation. In addition, the shorter time to complication detection in the observation group may partly reflect more frequent and ultrasound-assisted surveillance rather than only lower clinical severity, and discharge-based satisfaction assessment may have been influenced by social desirability bias. The generalizability of the findings, therefore, requires further verification in adequately powered prospective multicenter studies. In addition, all data were derived from the hospital electronic medical record system, and some subjective indicators may have been affected by recall bias or incomplete documentation. Moreover, the follow-up period in this study was relatively short, so the long-term effect of this model on vascular function was not assessed. The possible moderating effects of different types of infusion drugs and different levels of nursing staff qualifications on the intervention effect were also not explored, and these issues warrant further investigation in future studies.

In summary, this exploratory before-and-after study suggests that the integrated nursing model of “precise selection - closed-loop maintenance - dynamic adjustment” for peripheral venous access based on vascular ultrasound assessment may help address several limitations of traditional experience-based management. By applying ultrasound assessment throughout the entire life cycle of venous access, it enables standardized and refined management of peripheral venous access. This model can not only improve clinical outcomes in patients but also enhance nursing efficiency and reduce healthcare costs. It therefore has promising clinical potential, although its effectiveness and generalizability should be confirmed in adequately powered prospective multicenter studies before broad implementation.

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
0.9% Sodium Chloride Injection	Sichuan Kelun Pharmaceutical Co., Ltd. (Chengdu, China)	/	Routine flushing and locking solution after intravenous infusion
Disposable Closed Intravenous Catheter	Becton Dickinson Medical Devices (Shanghai) Co., Ltd. (BD)	/	Used for establishing upper extremity peripheral venous access
Disposable Intravenous Infusion Set	Shandong Weigao Group Medical Polymer Products Co., Ltd.	/	0.7 mm × 25 mm specification; Special consumable for clinical intravenous drug administration
Disposable Sterile Transparent Dressing	3M China Co., Ltd.	1624W	Fixation and protection of venous puncture site, routine replacement every 7 days
Electronic Medical Record System (EMR)	Beijing Jiahui Hemkang Information Technology Co., Ltd.	version 6.0	Extracts patient clinical diagnosis and treatment, laboratory tests, underlying diseases, and combined medication records
Hospital Information System (HIS)	Donghua Medical Technology Co., Ltd.	version 5.0	Extracts patient basic information, diagnosis and treatment records, and direct medical cost data related to venous access
Medical Electronic Timer	Shanghai Medical Device Co., Ltd.	JS-03	Accurately records time indicators such as puncture operation time, complication handling time, and handover time
Nursing Information System (NIS)	Weining Health Technology Group Co., Ltd.	version 4.5	Extracts nursing scheduling, venous access care operations, complication handling, and handover records
Portable Color Doppler Ultrasound Machine	Shenzhen Mindray Biomedical Electronics Co., Ltd.	M7	Quantitative assessment of peripheral venous vessel diameter, wall thickness, blood flow velocity and real-time guidance for puncture
SPSS Statistical Software	IBM Corp. (Armonk, New York, USA)	version 26	Statistical analysis of all measurement, count and ordinal data for research
Visual Analog Scale (VAS) Ruler	Jiangsu Yuyue Medical Equipment Co., Ltd.	YV-01	Used for quantitative assessment of patient pain level during puncture