Validating respiratory rate measurements in patients receiving high flow nasal cannula: a comparative study of Nellcor PM1000N and visual inspection

Recently, the Nellcor PM1000N was developed for the concurrent assessment of respiratory rate and percutaneous oxygen saturation. However, the validation of respiratory rate measurements in patients receiving a high-flow nasal cannula (HFNC) using the PM1000N remains unestablished. Therefore, this study aimed to assess the validity of respiratory rate measurements obtained using PM1000N in patients receiving HFNC. A retrospective assessment was conducted on the respiratory rate measurements obtained using the PM1000N and electrocardiogram (ECG) impedance methods in comparison to those visually assessed by nurses. This evaluation included patients admitted to the Intensive Care Unit (ICU) of Sapporo Medical University Hospital who received HFNC between June 2022 and December 2022. Correlation coefficients, intraclass correlation coefficients (ICCs), Bland–Altman plots, and t-tests were employed to assess the concordance between the visually observed respiratory rates by nurses and those recorded by the PM1000N and ECG impedance. Twenty patients were enrolled in this study. Among them, 119 instances of respiratory rate were recorded. The ICCs for the PM1000N and impedance methods were 0.918 and 0.846, respectively, compared with the rates visually assessed by nurses. The mean differences were p = 0.947 (95% CI −3.186 to 0.2987) and p < .001 (95% CI 16.4609–17.9532), respectively. The PM1000N demonstrated superiority over ECG impedance in measuring respiratory rate in patients with HFNC. Furthermore, PM1000N shows promise for effective application in patients receiving HFNC.