(2024) 24:507
Jeon et al. BMC Pediatrics
https://doi.org/10.1186/s12887-024-04990-x

BMC Pediatrics

RESEARCH

Open Access

Learning curve of ultrasound-guided
percutaneous central venous port placementin children
Ho Jong Jeon1, Kyong Ihn2 and In Geol Ho2*

Abstract
Background Although percutaneous central venous port (CVP) placement can be quickly performed using minimally invasive surgery, short- and long-term complications can occur. Beginner pediatric surgeons must overcome
learning curves influencing operative time and complication rates. However, few studies have been conductedon the learning curve of ultrasound-guided percutaneous CVP placement. This study analyzed the progress, results,
complications, and learning curve of ultrasound-guided percutaneous CVP placement in children performed by a single beginner pediatric surgeon.
Methods Data from 30 children who underwent ultrasound-guided percutaneous CVP placement were reviewed.
The patient characteristics, procedure indications, access veins, operator positions, operative times, and complication
rates were analyzed.
Results Cumulative sum analysis revealed two stages in the learning curve: stage 1 (initial 15 cases) and stage 2(subsequent cases). There was a correlation between the number of cases and operative time (Pearson correlation = -0.499, p = 0.005); the operative time was significantly longer in the first than in the second stage (p = 0.007).
Although surgical complications occurred more frequently in the early (26.7%) than in the late stage, it was not significantly different between the two stages (p = 0.1). During the study period, the operative time was significantly
reduced owing to the change in the operator’s position from the patient’s right side to the patient’s head (p = 0.005).
Conclusions Ultrasound-guided percutaneous CVP placement was a safe surgery that allowed a beginner pediatricsurgeon to overcome the learning curve after only 15 cases and involved a relatively small number of complications
compared with other pediatric surgeries. Additionally, the suitable position of the operator affected the surgicaloutcomes.
Keywords Central venous port, Learning curve, Complication rate, Operative time

*Correspondence:
In Geol Hohnjklop@yuhs.ac
1
Division of Pediatric Surgery, Department of Surgery, National Health
Insurance Service Ilsan Hospital, Goyang, Republic of Korea
2
Division of Pediatric Surgery, Department of Surgery, Ludlow Faculty
Building, Severance Children’s Hospital, Yonsei University Collegeof Medicine, 50 Yonsei‑Ro, Seodaemun‑Gu, Seoul 03722, Republicof Korea

BackgroundCentral venous port (CVP) placement is necessary inpediatric patients diagnosed with malignancies requiring
chemotherapy or chronic conditions requiring long-term
intravenous treatment [1, 2]. Compared with tunneled central lines, implantable CVPs are associated with lower ratesof bloodstream infection and a lower likelihood of requiring revision or replacement over the duration of therapy[3]. CVP placement surgery in children requires access toan experienced pediatric surgeon and general anesthesia© The Author(s) 2024. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which
permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to theoriginal author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images orother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line
to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory
regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of thislicence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Jeon et al. BMC Pediatrics(2024) 24:507

due to the small size of the anatomical structures, and thefear of interventional radiological procedures under local
anesthesia cannot be overcome as in adults.
CVP placement in children is a safe procedure with alow complication rate [4]. Previous studies have shownthat ultrasonography-guided venous access is preferred
for both adults and children, and many pediatric surgeons
opt for this procedure for CVP placement [4–7]. Although
CVP placement can be performed quickly using minimallyinvasive surgery, short- and long-term complications may
occur, including pneumothorax, hemothorax, arterial
puncture, infection, hematoma, thrombosis, and woundproblems [8–10]. Pediatric surgeons will likely experience
these complications at least once.
Beginner pediatric surgeons must overcome learning
curves that influence both operative time and complication
rates; however, few studies have been conducted on thelearning curve of ultrasound-guided percutaneous CVP
placement. This study aimed to analyze the progress, outcomes, complications, and learning curve of ultrasoundguided percutaneous CVP placement performed by asingle beginner pediatric surgeon and share the resultswith other beginner pediatric surgeons.

Methods
Study design

This retrospective study included 30 patients who underwent ultrasound-guided percutaneous CVP placement bya single beginner pediatric surgeon at Severance Children’s
Hospital between July 2021 and December 2022. The study
was approved by the National Health Insurance Ilsan Hospital (No. 2023–03-046) and the Severance Hospital, Yonsei
University Health System (No. 4–2022-1531) Institutional
Review Board, and it was conducted according to the tenets of the Helsinki Declaration. This retrospective study
was waived from informed consent by the National Health
Insurance Ilsan Hospital and the Severance Hospital, Yonsei University Health System Institutional Review Board.
Patient characteristics, procedure indications, access veins,
operator positions, operative times, and complication rates
were obtained from patients’ medical records and analyzed.
The operative time was defined as the time from the operator’s declaration of the start of surgery to the completion of
the operation site closure.

Surgical procedure for ultrasound‑guided
percutaneous CVP placement
The product used in all CVP placements was the Powerport® (Bard Access Systems, Salt Lake City, UT, USA).
CVP lines were inserted into the right or left internal jugular veins under general anesthesia using the ultrasoundguided Seldinger technique. Key steps include:

Page 2 of 6

1. Vein Identification and Puncture: The internal jugularvein is identified using continuous ultrasound guidance and punctured with a 21-gauge needle.
2. Guidewire Insertion: A guidewire is inserted throughthe needle into the superior vena cava, followed byneedle removal and site compression to prevent
hematoma.
3. Incision and Pocket Creation: An incision matching
the CVP diameter is made, the pectoralis major fascia is exposed, and a subcutaneous pocket is created
to secure the CVP.
4. Securing the CVP: The CVP is fixed to the pectoralis
major fascia with a nonabsorbable suture to prevent
migration.
5. Catheter Pathway Preparation: A small incision parallel to the clavicle is made to allow the introductionof a tunneler, vessel dilator, and sheath introducer. A
subcutaneous tunnel is created from the pocket tothe puncture site.
6. Catheter Insertion: The catheter is cut to length, andits tip is placed at the junction of the superior vena
cava and right atrium. The vessel dilator and guidewire are removed, and the CVP catheter is inserted
through the sheath into the vessel.
7. Flow Test and Securing: The sheath is removed, anda flow test is conducted to ensure no obstructions orleaks. The catheter is flushed and locked with heparinized saline.
8. Verification: The correct position of the catheter tip
is verified with portable chest radiography.
Statistical analyses

Cumulative sum (CUSUM) analysis was used as a quantitative method to analyze the learning curve. The t-test,
Chi-squared test, Fisher’s exact test, and Mann–Whitney
U-test were used for the comparative analysis of eachdata point. Statistical significance was set at p < 0.05. All
statistical analyses were performed using IBM SPSS Statistics ver. 26.0 (IBM Co., Armonk, NY, USA).

Results
The cohort (N = 30) included 18 males (60.0%) and 12
females (40.0%). The median age at which surgery was
performed was 6.7 (3.5–10.3) years. The patients’ medianweight at the time of surgery was 23.8 kg (15.7–41.7),
median height was 120.3 cm (99.3–142.3), and medianbody mass index (BMI) was 17.7 kg/m2 (15.7–20.2). The
most common indication for surgery was oncologic disease (96.7%) (Table 1).
The chart of the CUSUM analysis, according to thetotal procedure time and number of complications,revealed two stages of the learning curve (Fig. 1). The

Jeon et al. BMC Pediatrics(2024) 24:507

CUSUM trend demonstrated an upward slope from the
1st to the 15th case and a sharp decline from the 16thcase onward. Therefore, two stages were defined: stage
1, corresponding to the section from the 1st to the 15th
case, and stage 2, corresponding to the section from the­16th to the ­30th case.

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Based on these results, a comparison of the demographic data and treatment outcomes is shown in
Table 1. The median age at which surgery was performed
showed no difference between the two stages (p = 0.174).
Patients in the two stages did not differ regarding weight(p = 0.325), height (p = 0.25), or BMI (p = 0.217). The
most common access vein was the right internal jugular

Table 1 Comparison of demographic data and treatment outcomes
Entire cohort (n = 30)

Stage 1 (n = 15)

Stage 2 (n = 15)

Male

18 (60.0%)

9 (60.0%)

9 (60.0%)

Female12 (40.0%)

6 (40.0%)

6 (40.0%)

6.7 (3.5–10.3)

5.5 (3.1–8.8)

9.2 (3.5–11.9)

Sex

Age at operation (years)

p-value
1.0

0.174

Weight (kg)23.8 (15.7–41.7)

20.6 (16.6–34.9)

40.7 (15.3–50.0)

0.325

Height (cm)120.3 (99.3–142.3)

119.2 (98.3–135.0)

137.9 (100.0–146.0)

0.25

BMI (kg/m2)

17.7 (15.7–20.2)

17.3 (15.7–19.2)

19.0 (16.4–22.1)

0.217

29 (96.7%)

15 (100.0%)

14 (93.3)

1 (3.3%)0 (0.0%)1 (6.7%)Right internal jugular vein

29 (96.7%)

15 (100.0%)

14 (93.3)

Left internal jugular vein

1 (3.3%)0 (0.0%)1 (6.7%)

Patient’s right side

6 (20.0%)

6 (40.0%)0 (0.0%)At the patient’s head

15 (100.0%)

Indications ­Oncologya
Others (general condition)b

1.0

Access veins

1.0

Operator’s position

0.017
24 (80.0%)

9 (60.0%)

Operative time (min)40.5 (24.0–16.0)

43.0 (40.0–50.0)

29.0 (20.0–43.0)

0.007

Complications

4 (13.3%)

4 (26.7%)

0 (0.0%)0.1

Follow-up duration (days)

181.0 (53.0–257.5)

254.0 (208.0–296.0)

54.0 (43.0–117.0)

Data are presented as median (interquartile range) or number (%)
a

Leukemia (11 cases, 37.9%), brain tumors (8 cases, 27.6%), solid tumors (8 cases, 27.6%), and lymphomas (2 cases, 6.9%)bMitochondrial cytopathy with pneumonia

Fig. 1 Cumulative sum (CUSUM) curves of operation times and complications for central venous port placement procedures< 0.001

Jeon et al. BMC Pediatrics(2024) 24:507

vein (96.7%), with no significant difference between thetwo stages. The operator’s position changed during thestudy period (20.0% of procedures performed on thepatient’s right side and 80.0% at the patient’s head); thedifference between the two stages was statistically significant (p = 0.017). The median operative time was 40.5 min,significantly different between the two stages (p = 0.007).
Complications were more frequent in the early thanlate stage (26.7% vs. 0.0%, respectively). However, the difference was not statistically significant (p = 0.1). Complications occurred in four cases, including percutaneouspuncture site hematoma, CVP catheter thrombosis, CVP
site infection, and arrhythmia due to an excessively longcatheter tip position. Although surgical complications
occurred, there was no first failure during the surgicalprocedure, so there were no second or more attempts.
The median follow-up duration was 181 (53.0–257.5)
days.
The increasing number of cases correlated with theoperative time (Pearson correlation (r) = -0.499, p = 0.005;
Fig. 2). No significant correlations were found between
the operative time and patient age (r = -0.193, p = 0.308),
weight (r = -0.213, p = 0.258), height (r = -0.221,
p = 0.240), or BMI (r = -0.099, p = 0.604).
The operator’s position started on the patient’s rightside, as learned from a supervisory pediatric surgeon,
but was moved near the patient’s head according to theoperator’s preference. There was no significant difference between the operator’s position and the occurrenceof complications. However, the operative time was significantly reduced owing to the change in the operator’s
position (p = 0.005; Table 2).

Page 4 of 6

Discussion
General approaches to central venous catheters include
traditional open surgical venous cutdowns and percutaneous procedures [7, 11–17]. Ultrasound-guided percutaneous central venous catheter placement was firstdescribed in adults in the 1990s and is widely used in
all age groups, including children [13–17]. Large-scalestudies on ultrasound-guided percutaneous CVP placement in children, as well as studies on the learning curves
associated with various central venous catheter placement procedures in children, have been published [4, 16,17]. However, few studies have been conducted on thelearning curve of ultrasound-guided percutaneous CVP
placement.
Using CUSUM analysis, this rare study on the learning
curve of ultrasound-guided CVP placement in children
demonstrated the presence of two learning stages: before
and after completing procedures in 15 cases. There was astatistically significant relationship between the numberof CVP placements performed and operative time: as thenumber of cases increased, the operative time decreased.
Although the statistical values differ, our study’s median
operative time of 29 min, compared with the mean
Table 2 Comparison of procedure outcomes according to theoperator’s position
Patient’s right side(n = 6)At thep-valuepatient’s head(n = 24)

Operative time (min) 47.0 (43.0–63.8)

33.5 (23.3–43.0) 0.005

Complications

2 (7.7%)

2 (33.3%)

Data are presented as median (interquartile range) or number (%)

Fig. 2 Correlation between the increasing number of cases and operative time. Pearson correlation = -0.499, p = 0.005

0.169

Jeon et al. BMC Pediatrics(2024) 24:507

value of 40 min in another study, is an advanced surgical outcome [4]. Previous studies have reported that 8–20
cases of ultrasound-guided percutaneous central venous
catheter placement are sufficient for training under thesupervision of an experienced surgeon [16, 18]. In thisstudy, although additional port-placement techniques
were added, 15 cases were required to achieve a learning
effect.
According to the literature, the complication rates ofultrasound-guided percutaneous central venous catheter placement in children vary between 2.4% and 13.9%[4, 19–21]. The complication rates in our study tended
to be higher than those reported in the literature, likely
owing to various factors; first, this study was conductedin a relatively small number of patients over a short
research period. Second, as a study of the learning curveof a beginner pediatric surgeon, differences in proficiency
are also a likely factor. There was no significant difference in the complication rates between the two stagesof the CUSUM analysis learning curve; this can also be
attributed to the aforementioned factors. Among thefour patients with complications, three cases — including CVP catheter thrombosis, CVP site infection, andarrhythmia due to a catheter tip that was too long —required a CVP change. No major life-threatening complications were observed.
This study demonstrated a relationship between theoperator’s position and surgical outcome, which was notpreviously investigated. In the first six cases, the operator’s position was on the patient’s right side, which waslearned from the supervisory pediatric surgeon. However,depending on the surgeon’s preference, the procedure
was moved near the patient’s head, and the remaining
24 cases were performed as such. In ultrasound-guided
percutaneous CVP catheter placement, the operator’s
position is not rigidly established; rather, it is determinedby the operator’s habits and preferences. The supervisory pediatric surgeon performed the procedure on thepatient’s right side based on his preference and to reduce
position changes and operative time. The beginner pediatric surgeon initially proceeded accordingly. However,after the beginner pediatric surgeon experienced a complication of percutaneous puncture site hematoma due
to discomfort during the procedure, the operator position was moved near the patient’s head due to preference.
Although there was no relationship between the operator’s position change and complication rate, the reduction in the operative time was a statistically significant
outcome. Thus, a suitable operator position affected thesurgical outcome owing to learning and experience.
This study has a few limitations, as it is a short-term
retrospective study of only one beginner pediatric surgeon with a small number of patients. It is expected

Page 5 of 6that statistically significant results regarding complication rates will be obtained through long-term research
involving more patients and more beginner pediatricsurgeons.

Conclusions
Using a CUSUM analysis, the current study revealed
two stages in the learning curve of ultrasound-guided
percutaneous CVP placement in children — before andafter 15 cases — and demonstrated improved outcomes
regarding operative times. Additionally, a suitable operator’s position affected the surgical outcomes.
Nevertheless, ultrasound-guided percutaneous CVP
placement is considered a safe surgery that allows a
beginner pediatric surgeon to overcome the learning
curve with only 15 cases and involves a relatively small
number of complications compared with other pediatricsurgeries. Overcoming the learning curve of ultrasoundguided percutaneous CVP placement is essential for
reducing the operative times and complication rates.
Abbreviations
BMI	Body mass index
CUSUM	Cumulative sum
CVP	Central venous port
Acknowledgements
Not applicable.
Authors’ contributions
HJJ was the beginner pediatric surgeon and main author who collected,
analyzed, and interpreted data. KI was the supervisory pediatric surgeon who
helped collect and analyze data. IGH was the supervisory pediatric surgeon
who had the idea to research the topic and was the supervisor of the whole
research process. All authors read and approved the final manuscript.
Funding
This editorial work was supported by the Clinical Medical Research Fund of
the National Health Insurance Service at Ilsan Hospital.
Availability of data and materials
Most of the data generated or analyzed during this study are included in thisarticle. Limited data can be provided on request to the main author (Dr. Ho
Jong Jeon) at gdijhj@nhimc.or.kr.

Declarations
Ethics approval and consent to participate
This study was approved by the National Health Insurance Ilsan Hospital (No.
2023–03-046) and the Severance Hospital, Yonsei University Health System(No. 4–2022-1531) institutional review board. All methods were performedin accordance with relevant guidelines and regulations in the Declaration of
Helsinki. This retrospective study was waived from informed consent by the
National Health Insurance Ilsan Hospital and the Severance Hospital, Yonsei
University Health System Institutional Review Board.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.

Jeon et al. BMC Pediatrics(2024) 24:507

Received: 28 December 2023 Accepted: 1 August 2024

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