Congenital syphilis in newborns requires intravenous antibiotic therapy, making reliable peripheral venous access essential. However, high rates of catheter failure and repeated punctures remain a significant clinical challenge. This randomized, controlled, parallel clinical trial aims to compare ultrasound-guided long peripheral intravenous catheters inserted by a specialized vascular access team with conventional short peripheral catheters inserted by neonatal nurses. A total of 104 newborns with congenital syphilis receiving intravenous penicillin will be randomly assigned to either group. The primary outcome is functional dwell time. Secondary outcomes include catheter failure, number of insertion attempts, first-attempt success, complications, and total number of devices required. The study hypothesizes that ultrasound-guided long peripheral catheters will improve vascular access outcomes, reduce complications, and minimize the need for repeated punctures.

Congenital syphilis remains a significant public health problem and requires prolonged intravenous antibiotic therapy, typically with crystalline penicillin. In this context, reliable peripheral venous access is essential to ensure treatment continuity and safety. However, vascular access in newborns is particularly challenging due to small vessel caliber, tissue fragility, and increased susceptibility to complications, often resulting in high rates of catheter failure and repeated insertion attempts.

Short peripheral intravenous catheters inserted using conventional techniques are the most commonly used devices in neonatal care. Despite their widespread use, these devices are associated with limited dwell time and a higher likelihood of failure. Current guidelines recommend the use of adjunct technologies, such as ultrasound guidance, as well as devices with longer dwell times to improve vascular access outcomes. Ultrasound-guided insertion allows better visualization of vessels, potentially increasing first-attempt success and reducing complications. In addition, long peripheral intravenous catheters may provide greater stability and prolonged functional use compared with short catheters.

This study is a randomized, controlled, parallel, prospective clinical trial designed to compare ultrasound-guided long peripheral intravenous catheters inserted by a specialized vascular access team with conventional short peripheral catheters inserted by neonatal nurses. The study will be conducted in the Neonatal Intermediate Care Unit of the Hospital de Clínicas de Porto Alegre, Brazil, between May 2026 and March 2028.

Eligible participants are newborns diagnosed with congenital syphilis who require intravenous antibiotic therapy with crystalline penicillin for a planned duration of ten days. After enrollment, participants will be randomly assigned to either the intervention group (ultrasound-guided long peripheral intravenous catheter) or the control group (short peripheral catheter inserted using conventional technique).

The primary outcome is functional catheter dwell time, defined as the duration from catheter insertion to removal due to completion of therapy or occurrence of failure. Secondary outcomes include catheter failure, number of insertion attempts, first-attempt success, incidence of complications (such as infiltration, extravasation, obstruction, and phlebitis), and total number of devices required during treatment.

Data will be collected prospectively using standardized forms, and outcome assessment will be performed by trained personnel not directly involved in catheter insertion. Statistical analysis will follow the intention-to-treat principle, and results will be reported in accordance with CONSORT guidelines.

It is hypothesized that ultrasound-guided long peripheral intravenous catheters will result in longer functional dwell time, fewer failures, and reduced need for repeated punctures, contributing to improved vascular preservation, enhanced patient safety, reduced neonatal pain and stress, and more efficient use of healthcare resources.

Inclusion Criteria:

• Newborns admitted to the Neonatal Intermediate Care Unit;
• Diagnosis of congenital syphilis;
• Indication for intravenous penicillin therapy for an estimated duration of 10 days;
• Enrollment on the first day of treatment.

Exclusion Criteria:

• Newborns who have received any type of peripheral venous catheter prior to study enrollment;
• Clinical instability at the time of vascular access indication and/or requirement for admission to a Neonatal Intensive Care Unit;
• Requirement for concomitant administration of another antimicrobial agent in addition to crystalline penicillin;
• Need for catheter insertion outside the operating hours of the Vascular Access Program (7:00 AM to 7:00 PM, Monday to Friday).

Prospective Randomized Open, Blinded End-point (PROBE Study)