Accuracy of continuous and real-time total hemoglobin during bimaxillary orthognathic surgery

Intraoperative hemoglobin (Hb) monitoring is critical for ensuring patient safety during bimaxillary orthognathic surgery. Intraoperative Hb monitoring performed using portable devices with arterial blood samples is invasive, is time-consuming, and lacks the ability to provide real-time information. This retrospective study investigated the correlation between continuous and real-time total Hb (SpHb) using a Masimo Radical 7 device and Hb levels derived by portable devices during bimaxillary orthognathic surgery.

Patients who underwent elective bimaxillary orthognathic surgery were enrolled. The correlation between SpHb and laboratory Hb (Lab-Hb) was evaluated immediately after the induction of anesthesia (T1) and at surgical closure (T2) and compared with postoperative Hb.

Eighty-eight patients were included. The correlation coefficients between SpHb and Lab-Hb were 0.795 and 0.859 at T1 and T2, respectively. The correlation coefficient between Lab-Hb at T2 and postoperative Hb was 0.918. A Bland-Altman analysis of the Lab-Hb at T2 and postoperative Hb showed a mean bias of 0.49.

In conclusion, here we demonstrated acceptable accuracy of the SpHb measured by the Masimo Radical 7 device during bimaxillary orthognathic surgery. However, SpHb is valuable as an adjunct value to Lab-Hb and a substitute for Hb monitoring due to its wide limits of agreement. These findings suggest that SpHb can help guide the timing of invasive blood sampling for Hb measurements, which may facilitate earlier intervention and treatment.