71 - A novel formula to estimate the pre-procedural insertion length of peripherally inserted central catheter (PICC) in neonates

Poster Number: 71
Publication Number: 71.437

Raja Ashok Koganti, All India Institute of Medical Sciences, New Delhi, Vijayawada, Andhra Pradesh, India; Mari Jeeva Sankar, AIIMS, New Delhi, New Delhi, Delhi, India; Devasenathipathy Kandasamy, All India Institute of Medical Sciences, New delhi, Delhi, India; Ramesh Agarwal, All india institute of medical sciences, New Delhi, Delhi, India; Ashok K Deorari, AIIMS New Delhi, New Delhi, Delhi, India; Akash Sharma, All India Institute of Medical Sciences, New Delhi, Delhi, India

Background: Positioning peripherally inserted central catheter (PICC) tip in an appropriate location is essential to avoid complications. Measures of surface anatomy (sum of the distance from elbow crease to the ipsilateral acromion and from the acromion to ipsilateral manubrium sterni) used conventionally to estimate the PICC insertion depth often yield a high malposition rate.

Objective: To formulate an equation to determine the pre-procedural insertion length of PICC in preterm and low birth weight (LBW) neonates, when inserted via the cubital fossa by using one or more of the following: weight (birth weight or weight at enrolment, whichever was higher), head circumference, chest circumference, sternal length, shoulder umbilical length, foot length, and post-menstrual age, along with the standard surface anatomy length.

Design/Methods: In this prospective observational study from a level-3 neonatal unit in India, we enrolled preterm and LBW neonates who required PICC insertion via the cubital fossa. The placement of PICCs was guided by ultrasonography, and the tip position was confirmed by contrast radiograph, the reference standard for PICC tip localization. Measurements of pre-defined anthropometric parameters were taken using standardized techniques. Univariable and multivariable regression analyses were performed using the pre-defined variables as independent variables. Coefficient of determination (R2) and ‘predicted risk of malposition’ (malposition ‘yes’ if the difference between the estimated length from the model using the formula and the ‘actual PICC length’ was beyond ± 0.5 cm) were used to select the final equation (Figure 1).

Results: Of the 67 events of PICC insertion between Feb 2019 and Aug 2020, 52 were analyzed (Figure 2). The mean (SD) gestation at birth was 30.2 (2.6) weeks, and the median birth weight was 982 g (IQR 761-1366). The proposed formula based on the multivariable regression model was ‘PICC insertion length (cm) = 2.5 + (0.7 x weight (kg)) + (0.6 x surface anatomy length (cm))’, for PICCs inserted via the cubital fossa. This model had an R2 of 0.84 and reduced the predicted risk of malposition from 65.4% to 25%, i.e., a relative reduction of 61.7% (95% CI, 34.7 to 77.6; p < 0.001)(Table 1). On post-hoc analysis, the surface anatomy length overestimated the ‘actual PICC length’ by 0.9 cm (95% CI: -1.1 to -0.7, p < 0.001).Conclusion(s): The proposed novel formula is a more accurate alternative to the conventional surface anatomy technique for estimating the length of insertion of PICC. It needs validation in a large cohort of preterm neonates before being widely adopted for use.
Figure.1 Methodology employed for statistical analysis (Laterality i.e., side of PICC insertion was accounted for during analyses)*Weight, head circumference, chest circumference, sternal length, shoulder umbilical length, foot length, surface anatomy length and post menstrual age
(R2: Coefficient of determination)
Figure.2 Study flowa Six neonates required PICC insertion twice and one infant thrice at different locations and time points
(PICC, Peripheral inserted central catheter)
b Two neonates required two PICC insertions on right and left side at different time points