Optimal Finger Selection for Perfusion Index Measurement in Patients with Stable Chronic Obstructive Pulmonary Disease

Abstract

Background: Chronic obstructive pulmonary disease (COPD) may effect chronic hypoxemia due to ventilation–perfusion mismatch. The perfusion index (PI) based on pulse oximetry reflects peripheral perfusion and may vary by measurement site.Objective: To evaluate differences in PI values among fingers to determine the most reliable site for PI measurement in patients with COPD.Methodology: This descriptive, cross-sectional observational study included patients with stable COPD attending the Pulmonology Clinic at Kolonel Abundjani General Hospital in August 2025. Subjects were recruited usingconsecutive sampling. Patient characteristics, including sex, age, smoking history, and the Brinkman index, were obtained from medical records. Perfusion index measurements were taken from all fingers of both hands using a pulse oximeter and analyzed using descriptive statistics.Results: A total of 22 patients with stable COPD were included. Most participants were male (86.4%) and aged over 55 years (86.4%), with the majority having a history of smoking and a Brinkman index of 200–600 (45.5%). The highest mean PI value in the right hand was observed in the ring finger (4.89 ± 3.12), while in the left hand it was found in the index finger (5.59 ± 3.41). PI values tended to be higher in several fingers of the left hand. A significant difference was observed only in the middle finger between the right and left hands (p = 0.012). Age and smoking history were not significantly associated with PI values (p > 0.05).Conclusion: PI measurements in patients with stable COPD varied across different fingers. The thumbs showed relatively more stable values and may represent more reliable sites for PI assessment.