The application of pulse oximeter for supraclavicular brachial block

The subclavian artery is the most important landmark of the supraclavicular brachial block. However, it is difficult to locate the artery by palpation in the patients with poor landmark. The present study was aimed to compare two localizing methods of the subclavian artery by a pulse oximeter or by palpation. One hundred patients were divided into three groups. Group A (Slim Group): 6 patients, Group B (Normal Weight Group): 75 and Group C (Obese Group): 19. All patients received both methods to locate the subclavian artery. The first method was by palpating the pulsation of the subclavian artery. The second was by observing the wave depression of the pulse oximeter while pressing supraclavicular area. It was found that the detection rate of the first method was 83.3% in Group A, 52.0% in Group B, 26.3% in Group C and 49.0% in overall patients. However, the detection rate of the second method was 100% in each group. It shows a significant difference between the two methods in Group B, Group C and all patients (P less than 0.001), but no difference in Group A (P = 0.68). There were 13 patients among the 100 patients undergoing surgery of the upper extremity. Seven of them whose pulsation was not clearly palpated but could be located exactly by pulse oximeter. Supraclavicular brachial block was still completed successfully in these 13 patients. No pneumothorax was found. Utilizing pulse oximeter in supraclavicular block provides a high detection rate of the pulsation of the subclavian artery and improves the reliability of the block, especially in the patients with poor landmark.