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.