Frailty and Ultrasound-Guided Central Venous Catheterization Difficulty in Adult Cardiac Surgery Patients (FRAILCVC)

Central venous catheterization via the internal jugular vein is routinely performed in adult cardiac surgery patients for perioperative hemodynamic monitoring and administration of vasoactive medications. Although ultrasound guidance has improved the success and safety of internal jugular vein catheterization, procedural difficulty still varies considerably among patients and may be influenced by patient-related factors beyond vascular anatomy.

Frailty is increasingly recognized as a marker of reduced physiological reserve and adverse perioperative outcomes. However, its relationship with the technical difficulty of ultrasound-guided internal jugular vein catheterization has not been well established. In addition to frailty, reduced muscle strength may reflect diminished physiological reserve and may be associated with anatomical characteristics influencing catheterization difficulty.

This prospective observational study aims to evaluate the association between preoperative frailty and the procedural difficulty of ultrasound-guided internal jugular vein catheterization in adult patients undergoing elective cardiac surgery. The study will also investigate the contribution of handgrip strength and preprocedural ultrasonographic characteristics of the internal jugular vein to catheterization difficulty.

Preoperative frailty will be assessed using the 9-point Clinical Frailty Scale (CFS), ranging from 1 (Very Fit) to 9 (Terminally Ill), with higher scores indicating greater frailty. Handgrip strength will be measured preoperatively using a calibrated hand dynamometer. Three measurements will be obtained from the dominant hand, and the mean value (kg) will be used for analysis. Low muscle strength will be defined according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria as <27 kg for men and <16 kg for women.

Before catheterization, ultrasound evaluation of the internal jugular vein will include anteroposterior and transverse vein diameters, cross-sectional area (CSA), common carotid artery diameter, skin-to-vein distance, overlap status, and sternocleidomastoid muscle thickness. According to the study protocol, CSA will be categorized as <50 mm², 50-100 mm², and >100 mm².

Catheterization difficulty will be assessed using the Gaber Procedural Difficulty Score. The score is based on four procedural domains: number of puncture attempts (1-3 points), cannulation time (1-3 points), procedure-related complications (1-3 points), and procedural success (1-2 points). Higher total scores indicate greater procedural difficulty. Difficult catheterization will be defined as a Gaber Procedural Difficulty Score >4.

The primary aim of this study is to evaluate the relationship between preoperative frailty status and handgrip strength, and the difficulty of ultrasound-guided internal jugular vein catheterization in patients undergoing elective cardiac surgery. Catheterization difficulty will be assessed using the Gaber Procedural Difficulty Index, and difficult catheterization will be defined as a Gaber score >4.

Secondary Objectives:

1. To evaluate the relationship between preoperative frailty status and handgrip strength, and the ultrasonographic anatomical characteristics of the internal jugular vein.
2. To investigate the independent predictive role of ultrasonographically measured anatomical parameters of the internal jugular vein in the development of difficult catheterization.