BACKGROUND: Monitoring the left atrial pressures (LAP) is an important perioperative management tool for maintaining adequate cardiac output. However, incorrect placement of the LAP-monitoring catheter tip often leads to inherent risk. This study aimed to evaluate the length of the LAP catheter in pediatric open-heart surgery and devise a simple formula to predict the ideal length of insertion based on correlated demographic and clinical characteristics. METHODS: We conducted a retrospective clinical cohort study involving 79 infant patients aged ≤ 1 year who underwent open-heart surgery and right internal jugular vein (RIJV) catheterization to monitor the LAP. Pearson correlation coefficient and multiple regression analysis were employed to determine the association between the optimal depth and patient characteristics. In the variable selection stage, Least Absolute Shrinkage and Selection Operator (LASSO) regression was utilized to select the most valuable variables as candidates for subsequent multiple regression analysis. Then a simple formula was derived to predict the ideal depth for the LAP measurement. RESULTS: The participants consisted of 50 (63.3%) males and 29 (36.7%) females. Among them, 10 patients (12.7%) were preterm. The average age was 4.4 months
the average weight was 5.5 kg, and the average height was 60.5 cm. Height, body surface area (BSA), weight, age, and head circumference were strongly associated with the ideal length of the catheter. In the LASSO regression analysis, height and weight had the highest correlation coefficients. In the multiple regression model, only height showed a significant effect (P <
0.001). Consequently, we developed a new height-based formula: L (cm) = 5 + 0.1 × height (cm). The proportion of optimal depth determined by the new simplified formula was 88.6%. CONCLUSIONS: Height was identified as the most significant individual predictor of ideal length in this study. The newly developed formula, L = 5.0 + 0.1 × height (cm), is feasible and can be utilized to determine the optimal depth of the catheter to monitor the LAP via RIJV during pediatric open-heart surgery.