Enhancing autonomy in PICC placement: The feasibility of single-operator bubble test technique

Abstract

Accurate tip positioning is essential during the placement of peripherally inserted central catheters (PICC) to ensure optimal function and reduce complications such as arrhythmias, thrombosis, or malposition. Intracavitary electrocardiography (IC-ECG) is considered the gold standard for intraprocedural tip confirmation, yet its use may be limited in specific patient populations or when ECG signals are not interpretable. The ultrasound-based “bubble test” (contrast-enhanced ultrasound, CEUS) represents a validated alternative; however, it traditionally requires two operators, potentially creating workflow inefficiencies and limiting its applicability in resourceconstrained settings. This article introduces a novel single-operator bubble test technique designed to streamline PICC tip confirmation by allowing one clinician to perform both the injection of agitated saline and the ultrasound assessment. The method relies on pre-positioning a convex probe on the upper abdomen before sterile draping and manipulating it externally through the drape during the procedure. A single ultrasound system equipped with both a linear and a convex probe is used, avoiding the need for two separate machines. This setup enables acquisition of subcostal cardiac views without compromising sterility. The workflow includes ultrasound-guided venous access, probe switching, bubble test execution, and catheter repositioning when needed. A preliminary descriptive case series of 10 adult patients, performed by three different experienced operators, demonstrated the feasibility and reproducibility of the technique, with successful real-time visualization of microbubbles in the right atrium in all cases and no immediate procedure-related complications. The single-operator approach offers multiple advantages: it increases procedural autonomy, reduces dependence on additional staff, enhances synchronization between contrast injection and image acquisition, and retains the radiation-free nature of the bubble test. Potential limitations include reduced image quality through sterile drapes, ergonomic challenges, and the need for advanced ultrasound skills, particularly in obtaining and interpreting subcostal cardiac views, which may not be achievable in all patients and therefore represents an intrinsic limitation of the technique. Furthermore, precautions must be taken to minimize any theoretical infection risk associated with manipulating a non-sterile probe beneath sterile drapes. Effective implementation requires appropriate equipment, targeted training, and integration into institutional protocols. While the traditional dual-operator method remains preferable when available, this single-operator technique provides a practical, safe, and efficient alternative for real-time PICC tip confirmation, particularly in high-volume or resource-limited clinical environments.