Validity of accuracy and trending ability of non-invasive continuous total hemoglobin measurement in complex spine surgery: a prospective cohort study

Abstract

Background Patients undergoing complex spine surgery present with multilevel spinal involvement, advanced age, and multiple comorbidities. Surgery is associated with significant blood loss and remarkable hemodynamic changes. The present study aimed to investigate the accuracy and trending ability of a non-invasive continuous method to monitor hemoglobin (SpHb) concentrations using a Radical-7™ Pulse CO-Oximeter in complex spine surgery. Methods Forty-nine patients who underwent complex spine surgery were enrolled in this prospective observational study. Multiple time points were established for data collection throughout the operation. Simultaneous SpHb–total hemoglobin (tHb) paired data were recorded for analyses. Linear regression analysis, Bland–Altman plot, four-quadrant plot, and Critchley polar plot were used to assess the accuracy and trending ability of the monitor. Results A total of 272 pairs of SpHb-tHb data were available and were divided into two groups based on the perfusion index (PI): PI values ≥1.0 ( n = 200) and PI values < 1.0 ( n = 72). The correction coefficients (r) between SpHb and tHb were 0.6946 and 0.6861 in the groups with PI values ≥1.0 and < 1.0, respectively ( P < 0000.1). In the ≥1.0 group, the mean bias was − 0.21 g/dL and the percentage error (PE) was 15.85%, whereas in the < 1.0 group, the mean bias was − 0.04 g/dL and the PE was 17.42%. Four-quadrant plot revealed a concordance rate of 85.11%, whereas the Critchley polar plot showed a concordance rate of 67.21%. Conclusions The present study demonstrates the acceptable accuracy of the Radical-7™ Pulse CO-Oximeter even with a low PI. However, the trending ability was limited and unsatisfactory.

Can perioperative hemodilution be monitored with non-invasive measurement of blood hemoglobin?

“…Data were collected over a period of almost 10 years, during which the algorithm for calculating non-invasive Hb is claimed to have been improved. However, more recent work on Hb during spinal surgery and liver transplantation [ 10 , 19 ] show almost identical accuracy and precision for the non-invasive Hb as we reported in 2010 [ 2 ]. These authors also studied the concordance between changes in invasive and non-invasive Hb during surgery [ 10 , 19 ].…”

“…However, more recent work on Hb during spinal surgery and liver transplantation [ 10 , 19 ] show almost identical accuracy and precision for the non-invasive Hb as we reported in 2010 [ 2 ]. These authors also studied the concordance between changes in invasive and non-invasive Hb during surgery [ 10 , 19 ]. However, we chose to present our results differently, as we obtained data at very short intervals, usually only 5–10 min, and up to 25 times per experiment.…”

“…The scattering was aggravated in the presence of a very low perfusion index. By contrast, Chang et al [ 10 ], found the accuracy of the Radical-7 to be good even when the perfusion index is below 1.0.…”

Multicenter comparison of three intraoperative hemoglobin trend monitoring methods

“…Studies of 48 vascular surgery patients [ 17 ] and of 70 patients undergoing major orthopedic surgery [ 18 ] concluded SpHb had clinically acceptable trending with ABGHb or tHb. In 49 patients undergoing spine surgery, change concordance was 85.1% when excluding SpHb with perfusion index under 1 [ 19 ]. When using the exclusion zones determined by measurement repeatability analysis but not excluding SpHb based on low perfusion index, SpHb concordance was 94.2%.…”

Accuracy of non-invasive haemoglobin measurements in patients undergoing transurethral resection of prostate surgery

“…Previous studies have also shown a negative biasness <1 g/dL in SpHb values on different surgical subsets. [ 13 14 ] Considering the magnitude of SpHb-tHb difference, 60% values fall within 1 g/dL, 23% were between 1 and 2 g/dL, and 17% were >2 g/dL, respectively. Butwick et al .…”