To evaluate the application of a self-designed ruler in limb circumference measurement of postoperative breast cancer patients.

According to the inclusion and exclusion criteria, 100 postoperative breast cancer patients treated in the Department of Thyroid, Breast and Hernia Surgery, Beijing Hospital from January to May 2021 were enrolled for a prospective study. The circumference of the upper arm was measured by the nurse and the patient separately using a normal soft ruler and this new ruler. After measurement, a survey was conducted in all patients using a self-designed questionnaire to investigate their experience. Pearson correlation analysis was used to explore the correlation between measurement values at the same site by two methods. The paired t test was used to compare the measurement time and the score in questionnaire. The Kappa test was used to analyze the independent degree of measurement in patients using different methods, and the paired χ² test was used to analyze their intention to use the new ruler at home.

The upper arm circumference measured by patients or nurses showed a high correlation using the normal ruler and this new ruler (above the elbow: r=0.847, 0.752; under the elbow: r=0.667, 0.859; all P<0.001). The measurement time using the new ruler was significantly lower than that using the normal ruler [patients: (13.22±6.13) s vs (76.66±36.22) s, t=-18.681, P<0.001; nurses: (11.03±1.74) s vs (14.25±1.69) s, t=-16.541, P<0.001]. The independent degree of measurement using the new ruler was better than that using the normal ruler (Kappa=0.011, 95%CI: -0.001-0.022, P=0.410). The scores in overall impression, operation difficulty and patient satisfaction with the new ruler were significantly higher than those with the normal ruler (t=-18.986, -18.855, -21.732, all P<0.001). The proportion of patients who were willing to use the new ruler at home was significantly higher than that of the normal rulers (97% vs 12%, χ²=81.103, P<0.001).

The new ruler has good accuracy, simple and convenient operation, and can be used as a tool for measuring arm circumference at home in postoperative patients with breast cancer.