Multicenter comparison of three intraoperative hemoglobin trend monitoring methods

Abstract

Transfusion decisions are guided by clinical factors and measured hemoglobin (Hb). Time required for blood sampling and analysis may cause Hb measurement to lag clinical conditions, thus continuous intraoperative Hb trend monitoring may provide useful information. This multicenter study was designed to compare three methods of determining intraoperative Hb changes (trend accuracy) to laboratory determined Hb changes. Adult surgical patients with planned arterial catheterization were studied. With each blood gas analysis performed, pulse cooximetry hemoglobin (SpHb) was recorded, and arterial blood Hb was measured by hematology (tHb), arterial blood gas cooximetry (ABGHb), and point of care (aHQHb) analyzers. Hb change was calculated and trend accuracy assessed by modified Bland-Altman analysis. Secondary measures included Hb measurement change direction agreement. Trend accuracy mean bias (95% limits of agreement; g/dl) for SpHb was 0.10 (− 1.14 to 1.35); for ABGHb was − 0.02 (− 1.06 to 1.02); and for aHQHb was 0.003 (− 0.95 to 0.95). Changes more than ± 0.5 g/dl agreed with tHb changes more than ± 0.25 g/dl in 94.2% (88.9-97.0%) SpHb changes, 98.9% (96.1-99.7%) ABGHb changes and 99.0% (96.4-99.7%) aHQHb changes. Sequential changes in SpHb, ABGHb and aHQHb exceeding ± 0.5 g/dl have similar agreement to the direction but not necessarily the magnitude of sequential tHb change. While Hb blood tests should continue to be used to inform transfusion decisions, intraoperative continuous noninvasive SpHb decreases more than − 0.5 g/dl could be a good indicator of the need to measure tHb.

Postoperative Noninvasive Hemoglobin Monitoring Is Useful to Prevent Unnoticed Postoperative Anemia and Inappropriate Blood Transfusion in Patients Undergoing Total Hip or Knee Arthroplasty: A Randomized Controlled Trial

“… 21 However, a recent multicenter study showed that the Hb accuracy mean bias for SpHb was 0.24 g/dL. 22 In vivo SpHb adjustment, which was used in this study, improved the accuracy of SpHb. 23 , 24 For a timely blood transfusion, the trending capability of SpHb is important, and it more accurately estimates the appropriate timing for invasive Hb measurements than do clinicians.…”

“… 23 , 24 For a timely blood transfusion, the trending capability of SpHb is important, and it more accurately estimates the appropriate timing for invasive Hb measurements than do clinicians. 22 , 25 - 27 However, SpHb monitoring is still controversial for postoperative management. It was reported to be unsuitable to maintain the Hb level >8 g/dL, particularly in those with lower Hb levels in the intensive care unit.…”

Accuracy and trending capability of haemoglobin measurement by noninvasive pulse co-oximetry in anaesthetized horses

“…1.4% groups has been demonstrated in human or veterinary patients (Miller et al 2011;Tayari et al 2021). A central exclusion zone for a change in [Hb] values of ± 0.5 g dL e1 was applied to rule out pairs of data with minimal difference (Applegate et al 2020). For the four-quadrant plot, the change in [Hb] measured by the reference method was plotted against the change in [Hb] measured by the test method in a regression style.…”

“…Our exclusion zones were defined based on 95% LoA, meaning that a change up to ± 0.5 g dL e1 may not reflect a real change in circulating haemoglobin measured. However, as the limits of the exclusion zone are arbitrarily defined, either based on absolute values or by percentage change (e.g., 10% or 15%), this could differ in other settings or when using different analysers and may present a limitation (Saugel et al 2015;Applegate et al 2020).…”

Non-invasive monitoring is coming the full circle, making our patients safer!

“…In this edition of JCMC, Applegate et al demonstrate that the improvement in technology in pulse oximetry is advancing the trend accuracy of non-invasive hemoglobin (SpHb) measurement [1]. This will hopefully lead to the end of the "stat" bring back to the operating room at 7 am in the morning of patients, when the routine morning laboratory results are reviewed.…”