Construction and application of a predictive model for optimal peripherally inserted central catheter (PICC) insertion depth in preterm infants under high-frequency ultrasound guidance based on clinical parameters

Objective: This study aims to construct and validate a predictive formula based on routine clinical parameters for determining the optimal catheter placement depth (OCPD) in preterm infants undergoing peripherally inserted central catheter (PICC) insertion via the basilic vein (BV) or axillary vein (AXV). The goal is to provide a standardized reference protocol for precise PICC placement in neonatal intensive care, with the aim of enhancing procedural accuracy and reducing catheter-related complications. Methods: This prospective study enrolled 105 preterm infants, who were categorized into two groups based on the puncture site: the basilic vein PICC group (BV-PICC, n = 59) and the axillary vein PICC group (AXV-PICC, n = 46). All catheter placements were performed under high-frequency ultrasound guidance to ensure accurate positioning and optimal catheter depth. The optimal catheter insertion length was recorded for each infant. Subsequently, clinical data were collected and analyzed, including gestational age, head circumference, chest circumference, maximum abdominal circumference, mid-forearm circumference, body weight, and body length. Multiple linear regression analysis was conducted to explore the relationship between optimal catheter depth and the clinical parameters of the preterm infants. Based on this analysis, a predictive formula for PICC insertion depth in preterm infants was developed using clinical parameters. Results: In the BV-PICC group, birth weight and weight at the time of catheterization were identified as significant predictors. The optimal catheter placement depth (cm) was calculated using the following formula: OCPD = 8.205 + 0.005 × birth weight (g)–0.003 × weight at catheterization (g). In the AXV-PICC group, only body length at catheterization was identified as a significant predictor. The formula was: OCPD = 1.024 + 0.177 × body length at catheterization (cm). Conclusion: The predictive formulas for the OCPD of PICC inserted via different pathways in preterm infants, developed under high-frequency ultrasound guidance and based on clinical parameters, demonstrated accuracy and excellent clinical applicability. These formulas provide a valuable reference for both standardized and individualized PICC placement in preterm infants, thereby facilitating evidence-based clinical decision-making and potentially reducing catheter-related complications.