Intraoperative continuous noninvasive hemoglobin monitoring in patients undergoing thoracic surgery

BACKGROUND: This study aims to assess the agreement between noninvasive hemoglobin (SpHb) and invasive hemoglobin (InvHb) monitoring in guiding blood transfusions during thoracic procedures. METHODS: This study was not interventional but assessed the agreement between SpHb and InvHb monitoring in guiding blood transfusions during thoracic procedures. Data were collected from 80 patients ≥ 18 years older who were candidates for thoracic surgeries. Continuous SpHb monitoring was conducted. Simultaneous (InvHb) samples were collected for validation at predefined perioperative intervals: preoperative baseline, immediately after induction, 1, 2, 3, and 4 h after incision, at the end of surgery, and in the recovery room. Agreement was assessed using Bland-Altman analysis, and correlation was evaluated using Pearson coefficients. The primary outcome measure was the correlation between SpHb and InvHb. RESULTS: There was a significant positive correlation between SpHb and InvHb at preoperative period, immediately after induction of anesthesia, 1 h, 2 h, 3 h, 4 h after start of surgery, at the end of surgery and after recovery of the patient (Pearson's r = 0.949772, 0.940262, 0.915292, 0.981438, 0.989623, 0.984838, 0.965235 and 0.933264). Bland-Altman analysis between SpHb and InvHb demonstrated low bias with good limits of agreement at the same interval points [Mean bias (limits of agreement): 0.56 (-0.3 to 1.4), 0.54 (-0.38 to 1.5), 0.67 (-0.37 to 1.7), 0.52 (-0.14 to 1.8), 0.48 (0.12 to 1.1), 0.6 (-0.001 to 1.2) g/dl]. CONCLUSION: In patients undergoing thoracic surgery, there is a strong correlation and acceptable agreement between SpHb monitoring using Masimo pulse co-oximetry and invasive hemoglobin measurements.