Establishing learning curve for Tenckhoff catheter insertion by interventional nephrologist using CUSUM analysis: how many procedures and in which situation?

Peritoneal dialysis (PD) catheter insertion success rate is known to vary among different operators, and peritoneoscope PD catheter insertion demands mastery of a steep learning curve. Defining a learning curve using a continuous monitoring tool such as a Cumulative Summation (CUSUM) chart is useful for planning training programs. We aimed to analyze the learning curve of a trainee nephrologist in performing peritoneoscope PD catheter implantation with CUSUM chart. This was a descriptive single-center study using collected data from all PD patients who underwent peritoneoscope PD catheter insertion in our hospital. CUSUM model was used to evaluate the learning curve for peritoneoscope PD catheter insertion. Unacceptable primary failure rate (i.e., catheter malfunction within 1 month of insertion) was defined at >40% and acceptable performance was defined at <25%. CUSUM chart showed the learning curve of a trainee in acquiring new skill. As the trainee became more skillful with training, the CUSUM curve flattened. Technical proficiency of the trainee nephrologist in performing peritoneoscope Tenckhoff catheter insertion (<25% primary catheter malfunction) was attained after 23 procedures. We also noted earlier in our program that Tenckhoff catheters directed to the right iliac fossae had poorer survival as compared to catheters directed to the left iliac fossae. Survival of catheters directed to the left iliac fossae was 94.6% while the survival for catheters directed to the right iliac fossae was 48.6% (p < 0.01). We advocate that quality control of Tenckhoff catheter insertion is performed using CUSUM charting as described to monitor primary catheter dysfunction (i.e., failure of catheter function within 1 month of insertion), primary leak (i.e., within 1 month of catheter insertion), and primary peritonitis (i.e., within 2 weeks of catheter insertion).