Fig 1.
Schematic illustration of the landmark-based PICC length calculation method.
(A) Anatomical landmarks identified at the bedside: the cubital crease (established by flexing the elbow to 90°) and the skin puncture point (determined by ultrasound guidance). (B) The formula calculates the total length (CP + CL), which represents the distance from the cubital crease to the CAJ. At the procedure site, the operator measures the actual distance from the cubital crease to the puncture point (CP, green line). The catheter trimming length (CL, purple line) is then determined by subtracting CP from the precalculated total length (CP + CL). The catheter is trimmed to CL before insertion, ensuring the tip reaches the designated CAJ level (defined as 2 VBU below the inferior carina border). PICC: peripherally inserted central catheter; CP: distance from cubital crease to puncture point; CL: catheter length; CAJ: cavoatrial junction; VBU: vertebral body unit.
Fig 2.
Definition of optimal, high, and deep PICC tip positions on anteroposterior chest radiography.
The cavoatrial junction (CAJ) is defined as 2 VBU below the inferior carina border. Optimal position (red zone) is the catheter tip located within ±2.8 cm of the designated CAJ. High position (green zone) indicates the tip located in the superior vena cava between the optimal zone and the right tracheobronchial angle. Deep position (blue zone) indicates the tip located in the right atrium below the optimal zone. CAJ: cavoatrial junction; VBU: vertebral body unit.
Fig 3.
Distribution of catheter tip-to-cavoatrial junction (CAJ) distances.
(A) Histograms of catheter-tip distributions for all bedside PICC procedures. The distribution is approximately symmetric around a median of 0 cm from the designated CAJ. (B) Q–Q plot of catheter tip-to-designated CAJ distance for all bedside PICC procedures, demonstrating an approximately normal distribution.
Fig 4.
Operator-specific histograms of catheter-tip distributions.
With the exception of operator B (n = 19), whose sample size is very small, tips are positioned approximately symmetrically around a median of 0 cm from the designated CAJ.
Fig 5.
Bedside PICC placement in a complex clinical environment with multiple concomitant intravascular devices.
Representative chest radiograph showing the coexistence of a same-side Permcath, a contralateral PICC, and two femoral extracorporeal membrane oxygenation (ECMO) sheaths. Despite the high clinical complexity and potential for device interference, the catheter tip is accurately localized at the target zone using the pre-procedural length prediction formula.