Central venous cannulation (CVC) is a commonly performed invasive procedure in critically ill patients and those undergoing major surgical interventions. It provides reliable venous access for administration of vasoactive drugs, parenteral nutrition, blood products, chemotherapy, hemodynamic monitoring, and rapid fluid resuscitation. Traditionally, central venous access has been obtained using the anatomical landmark technique, which relies on surface anatomical landmarks to guide needle insertion. Although widely practiced, this technique is associated with variable success rates and procedure-related complications such as arterial puncture, hematoma, pneumothorax, hemothorax, catheter malposition, and failed cannulation attempts, particularly in patients with obesity, altered anatomy, or hemodynamic instability. These complications may increase patient morbidity, prolong hospital stay, and escalate healthcare costs.[1]

The introduction of ultrasound guidance has revolutionized vascular access procedures by enabling real-time visualization of the target vein, adjacent structures, and needle trajectory. Ultrasound-guided central venous cannulation allows direct assessment of vessel patency, size, depth, and anatomical variations before and during cannulation. Numerous studies have demonstrated that ultrasound guidance improves first-pass success rates, reduces the number of attempts required for successful catheter placement, shortens procedure time, and minimizes mechanical complications. Consequently, several professional organizations, including anesthesiology and critical care societies, recommend ultrasound-guided cannulation as the preferred method for internal jugular vein access.[2][3]

Despite the increasing availability of ultrasound machines, the landmark technique continues to be practiced in many healthcare settings because of limited resources, lack of training, emergency situations, or operator preference. Therefore, understanding the comparative effectiveness of ultrasound-guided and landmark techniques remains clinically relevant. Previous studies have reported varying outcomes depending on operator experience, patient characteristics, and site of cannulation. While some investigations have shown significantly higher success rates and lower complication rates with ultrasound guidance, others have reported comparable outcomes when procedures are performed by experienced clinicians. Moreover, evidence from developing countries and resource-limited settings remains relatively limited.[4]

AIM

To compare the success rate and complications of ultrasound-guided versus landmark technique for central venous cannulation.

OBJECTIVES

1. To compare the overall and first-attempt success rates between ultrasound-guided and landmark techniques for central venous cannulation.
2. To compare the number of attempts and time required for successful cannulation between the two techniques.
3. To evaluate and compare the incidence of procedure-related complications associated with both techniques.

Source of Data The data were collected from patients requiring central venous cannulation admitted to the Intensive Care Unit (ICU), Emergency Department, and Operation Theatres of the tertiary care teaching hospital during the study period. Relevant demographic, clinical, procedural, and outcome-related information was obtained from patient records and direct observation during the procedure. Study Design Hospital-based comparative cross-sectional study. Study Location The study was conducted in the Department of Anaesthesiology and Critical Care at a tertiary care teaching hospital. Study Duration The study was conducted over a period of 18 months from January 2024 to June 2025 (or as per institutional study period). Sample Size A total of 200 patients requiring central venous cannulation were included in the study. • Group U (Ultrasound-guided technique): 100 patients • Group L (Landmark technique): 100 patients The sample size was determined based on feasibility, expected patient load, and previous studies comparing success rates and complication profiles of central venous cannulation techniques. Inclusion Criteria 1. Patients aged ≥18 years requiring central venous catheterization. 2. Patients admitted to ICU, emergency department, or operation theatre requiring central venous access for clinical management. 3. Patients who provided written informed consent or whose legally authorized representatives provided consent. 4. Elective and emergency cases requiring internal jugular, subclavian, or femoral venous cannulation. Exclusion Criteria 1. Patients younger than 18 years. 2. Patients with local infection at the proposed cannulation site. 3. Patients with severe coagulopathy or platelet count <50,000/mm³. 4. Patients with known venous thrombosis at the cannulation site. 5. Patients with distorted neck anatomy, extensive burns, or previous surgery affecting the cannulation site. 6. Patients who refused consent. Procedure and Methodology After obtaining approval from the Institutional Ethics Committee and written informed consent, eligible patients were enrolled in the study. Baseline demographic details including age, sex, body mass index, diagnosis, indication for central venous access, and comorbidities were recorded. Patients underwent central venous cannulation either by the ultrasound-guided technique or by the conventional landmark technique according to the availability of equipment and operator preference. Ultrasound-Guided Group A high-frequency linear ultrasound probe covered with a sterile sheath was used. The target vein was identified in transverse and longitudinal views. Vessel patency, diameter, depth, and anatomical relationships were assessed. Under real-time ultrasound visualization, the needle was advanced into the vein and successful venous puncture was confirmed by free aspiration of venous blood. Guidewire insertion, dilatation, and catheter placement were completed using the Seldinger technique. Landmark Technique Group The anatomical landmarks corresponding to the selected venous access site were identified. The puncture needle was introduced according to standard landmark-guided recommendations. Following successful venous aspiration, catheter placement was completed using the Seldinger technique. For each procedure, the following variables were recorded: • Site of cannulation • Number of attempts • First-pass success • Overall success • Time taken for successful cannulation • Need for alternative site • Procedure-related complications Complications Evaluated • Arterial puncture • Hematoma formation • Pneumothorax • Hemothorax • Catheter malposition • Failed cannulation • Multiple puncture attempts (>3) • Local bleeding • Arrhythmias during guidewire insertion Post-procedure chest radiography was performed where indicated to confirm catheter position and detect complications. Sample Processing No biological sample processing was involved in the present study. Procedural and clinical data were recorded immediately after cannulation using a structured case record form. Data were verified and entered into a master database for analysis. Data Collection Data were collected using a predesigned and pretested case record form containing: • Demographic characteristics • Clinical diagnosis • Indication for CVC insertion • Cannulation site • Technique used • Number of attempts • Time required for cannulation • Success rate • Immediate procedural complications • Post-procedure outcomes All information was entered into Microsoft Excel and cross-checked for completeness and accuracy before statistical analysis. Statistical Methods Data were entered in Microsoft Excel and analyzed using Statistical Package for Social Sciences (SPSS) version 26.0. • Continuous variables were expressed as Mean ± Standard Deviation (SD). • Categorical variables were expressed as frequencies and percentages. • Independent Student's t-test was used to compare continuous variables between groups. • Chi-square test or Fisher's exact test was used for comparison of categorical variables. • Odds ratios (OR) with 95% confidence intervals (CI) were calculated where appropriate. • A p-value <0.05 was considered statistically significant. • Results were presented using tables, graphs, and charts.

Table 1. Baseline Characteristics and Overall Comparison of Study Participants (N=200)

Table 1 presents the baseline characteristics and overall outcomes of the study participants. The mean age of patients in the ultrasound-guided group was 48.7 ± 13.6 years compared to 50.9 ± 14.1 years in the landmark group, with no statistically significant difference between the groups (t=1.12, p=0.263). Male participants constituted 60.4% of the ultrasound-guided group and 63.6% of the landmark group, showing comparable gender distribution (χ²=0.22, p=0.641). Similarly, the mean BMI was 24.8 ± 3.7 kg/m² in the ultrasound-guided group and 25.1 ± 3.9 kg/m² in the landmark group, without significant difference (t=0.56, p=0.578). ICU-related indications for central venous cannulation were observed in 47.5% and 52.5% of patients in the ultrasound-guided and landmark groups, respectively (χ²=0.50, p=0.481). However, overall successful cannulation was significantly higher in the ultrasound-guided group (96.0%) compared with the landmark group (87.9%) (χ²=4.52, p=0.033). Furthermore, the incidence of any procedure-related complication was significantly lower in the ultrasound-guided group (7.9%) than in the landmark group (24.2%) (χ²=9.91, p=0.002).

Table 2. Overall and First-attempt Success Rates Between Techniques (N=200)

Table 2 compares the success rates of central venous cannulation between ultrasound-guided and landmark techniques. First-attempt success was achieved in 80.2% of patients in the ultrasound-guided group compared with 54.5% in the landmark group, demonstrating a highly significant advantage for ultrasound guidance (χ²=15.00, p<0.001). Second-attempt success occurred in 11.9% of the ultrasound-guided group and 24.2% of the landmark group, with the difference being statistically significant (χ²=5.19, p=0.023). Third-attempt success was observed in 4.0% and 9.1% of patients, respectively, although this difference did not reach statistical significance (χ²=2.18, p=0.140). Overall successful cannulation was significantly higher in the ultrasound-guided group (96.0%) than in the landmark group (87.9%) (χ²=4.52, p=0.033). Conversely, failed cannulation was significantly less frequent in the ultrasound-guided group (4.0%) compared to the landmark group (12.1%) (χ²=4.47, p=0.035).

Table 3. Number of Attempts and Time Required for Successful Cannulation (N=200)

Table 3 evaluates the procedural efficiency of ultrasound-guided and landmark techniques in terms of number of attempts and time required for successful cannulation. The mean number of attempts required for successful cannulation was significantly lower in the ultrasound-guided group (1.36 ± 0.72) compared to the landmark group (2.08 ± 1.04) (t=5.68, p<0.001). Similarly, the mean cannulation time was significantly shorter with ultrasound guidance (5.86 ± 2.13 minutes) than with the landmark technique (9.74 ± 3.68 minutes) (t=9.10, p<0.001). Successful cannulation in a single attempt was achieved in 80.2% of patients in the ultrasound-guided group versus 54.5% in the landmark group (χ²=15.00, p<0.001). More than one attempt was required in only 15.8% of ultrasound-guided procedures compared with 33.3% of landmark-guided procedures (χ²=8.28, p=0.004). Likewise, the requirement of more than three attempts was significantly lower in the ultrasound-guided group (4.0%) than in the landmark group (12.1%) (χ²=4.47, p=0.035).

Table 4. Procedure-related Complications Between Techniques (N=200)

Table 4 compares the incidence of procedure-related complications between ultrasound-guided and landmark techniques. Overall complications occurred in only 7.9% of patients in the ultrasound-guided group compared with 24.2% in the landmark group, representing a statistically significant reduction (χ²=9.91, p=0.002). Arterial puncture was significantly less common with ultrasound guidance (3.0%) than with the landmark technique (13.1%) (χ²=7.01, p=0.008). Similarly, hematoma formation occurred in 4.0% of the ultrasound-guided group and 14.1% of the landmark group (χ²=6.33, p=0.012). Pneumothorax was observed in only 2.0% of ultrasound-guided procedures compared with 9.1% of landmark-guided procedures (χ²=4.86, p=0.027). Catheter malposition was significantly lower in the ultrasound-guided group (3.0%) than in the landmark group (11.1%) (χ²=5.09, p=0.024). Likewise, local bleeding occurred less frequently with ultrasound guidance (5.0%) compared with the landmark technique (17.2%) (χ²=7.63, p=0.006).

In the present study, baseline variables were comparable between the ultrasound-guided and landmark groups with respect to age, sex, BMI and ICU indication, suggesting that both groups were clinically similar before comparison. However, overall successful cannulation was significantly higher in the ultrasound-guided group than in the landmark group (96.0% vs 87.9%, p=0.033), while overall complications were significantly lower (7.9% vs 24.2%, p=0.002). These findings are consistent with Randolph et al. (1996)[1] and Hind et al. (2003)[2], who reported that ultrasound guidance improves success rates and reduces mechanical complications during central venous catheterization. Karakitsos et al. (2006)[3] also observed superior outcomes with real-time ultrasound-guided internal jugular vein cannulation compared with the anatomical landmark technique. First-attempt success was significantly higher in the ultrasound-guided group (80.2%) than in the landmark group (54.5%) (p<0.001). Failed cannulation was also significantly lower with ultrasound guidance (4.0% vs 12.1%, p=0.035). Similar findings were reported by Karakitsos et al. (2006)[3], who demonstrated improved first-pass success and fewer failed attempts using real-time ultrasound. Troianos et al. (2012)[4] recommended ultrasound guidance for vascular cannulation because it allows visualization of the vein, surrounding structures and needle path, thereby improving accuracy and safety. The present study also showed that the ultrasound-guided technique required fewer attempts and shorter cannulation time. The mean number of attempts was significantly lower in the ultrasound-guided group (1.36 ± 0.72) compared with the landmark group (2.08 ± 1.04) (p<0.001). Mean cannulation time was also significantly shorter with ultrasound guidance (5.86 ± 2.13 minutes vs 9.74 ± 3.68 minutes, p<0.001). These observations are supported by Lamperti et al. (2012)[5], who emphasized that ultrasound guidance reduces procedure time, improves technical success and enhances safety during central venous access. A recent comparative study also reported higher first-attempt success, fewer attempts and lower complication rates with ultrasound-guided cannulation compared with non-ultrasound technique[6]. Regarding complications, the present study found significantly lower rates of arterial puncture, hematoma, pneumothorax, catheter malposition and local bleeding in the ultrasound-guided group. Arterial puncture occurred in 3.0% of ultrasound-guided cases compared with 13.1% in landmark cases (p=0.008), while hematoma was seen in 4.0% and 14.1%, respectively (p=0.012). These findings are comparable with the American Society of Echocardiography and Society of Cardiovascular Anesthesiologists guidelines, which state that ultrasound guidance reduces complications by allowing direct visualization of the vessel and adjacent artery[4]. The American College of Surgeons also states that real-time ultrasound guidance increases success rate while decreasing procedure time and complications[7].

The present study demonstrated that ultrasound-guided central venous cannulation is superior to the conventional landmark technique in terms of procedural success and safety. Ultrasound guidance was associated with significantly higher first-attempt success rates, improved overall cannulation success, fewer needle passes, and shorter procedure duration. Furthermore, the incidence of procedure-related complications, including arterial puncture, hematoma, pneumothorax, catheter malposition, and local bleeding, was significantly lower in the ultrasound-guided group. These findings support the routine use of ultrasound guidance for central venous access whenever equipment and trained personnel are available. Adoption of ultrasound-guided cannulation may improve patient outcomes, enhance procedural efficiency, and reduce complications associated with central venous catheter placement.

LIMITATIONS OF THE STUDY

1. The study was conducted at a single tertiary care center, which may limit the generalizability of the findings to other healthcare settings.
2. The cross-sectional design did not permit long-term follow-up for delayed complications such as catheter-related bloodstream infections or thrombosis.
3. Operator experience and skill level were not standardized across all procedures and may have influenced success rates and complication profiles.
4. Different central venous access sites (internal jugular, subclavian, and femoral veins) were included, which could have affected procedural outcomes.
5. The study did not evaluate cost-effectiveness, resource utilization, or learning curves associated with ultrasound-guided cannulation.
6. Blinding of operators was not feasible because of the nature of the intervention, introducing the possibility of performance bias.
7. The sample size, although adequate for primary outcomes, may not have been sufficient to assess rare complications with high precision.

1. Randolph AG, Cook DJ, Gonzales CA, Pribble CG. Ultrasound guidance for placement of central venous catheters: A meta-analysis of the literature. Crit Care Med. 1996;24(12):2053-2058.
2. Hind D, Calvert N, McWilliams R, Davidson A, Paisley S, Beverley C, et al. Ultrasonic locating devices for central venous cannulation: Meta-analysis. BMJ. 2003;327(7411):361.
3. Karakitsos D, Labropoulos N, De Groot E, Patrianakos AP, Kouraklis G, Poularas J, et al. Real-time ultrasound-guided catheterisation of the internal jugular vein: A prospective comparison with the landmark technique. Crit Care. 2006;10(6):R162.
4. Troianos CA, Hartman GS, Glas KE, Skubas NJ, Eberhardt RT, Walker JD, et al. Guidelines for performing ultrasound guided vascular cannulation. Anesth Analg. 2012;114(1):46-72.
5. Lamperti M, Bodenham AR, Pittiruti M, Blaivas M, Augoustides JG, Elbarbary M, et al. International evidence-based recommendations on ultrasound-guided vascular access. Intensive Care Med. 2012;38(7):1105-1117.
6. Dileep P, Kumar A, Singh R, Sharma V. Comparison of ultrasound versus non-ultrasound based technique for central venous cannulation. Natl Board Med J. 2024;2(1):1-6.
7. American College of Surgeons. Revised statement on recommendations for use of real-time ultrasound guidance for placement of central venous catheters. Bull Am Coll Surg. 2011;96(6):36-37.
8. Ortega R, Song M, Hansen CJ, Barash P. Ultrasound-guided internal jugular vein cannulation. N Engl J Med. 2010;362(16):e57.