Noninvasive spectrophotometric hemoglobin sensor performs well with time, at high perfusion
WEDNESDAY, April 20 (HealthDay News) -- Use of a continuous spectrophotometric hemoglobin (SpHb) sensor may be a useful new approach for noninvasive blood hemoglobin monitoring during surgery, according to a study published in the April issue of Anesthesia & Analgesia.
Ronald D. Miller, M.D., from the University of California in San Francisco, and colleagues compared the accuracy of SpHb and point-of-care HemoCue (HCue) to that of the invasive laboratory Co-Oximetry (tHb) method for monitoring blood hemoglobin during perioperative transfusions. A total of 78 measurements of SpHb, tHb, and HCue were made on 20 patients, aged 40 to 80 years, after induction of anesthesia, before and during spine surgery. Absolute and observed differences between SpHb and tHb and HCue and tHb measures were the main outcomes of the study. Observed differences were evaluated in relation to age, weight, tHb level, duration of surgery, and perfusion index.
The investigators found an absolute differences of less than 1.5 g/dL between SpHb and tHb in 61 percent of the observations, between 1.6 and 2.0 g/dL in 16 percent, and greater than 2.0 g/dL in 22 percent of the observations. The observed differences decreased significantly with time and increased perfusion index values, but showed no correlation with age or weight. All the HCue values were less than 1.0 g/dL different to the tHb value, except one.
"Although HCue was consistently accurate, our data confirm that SpHb often correlated well with tHb values. Yet our study indicates that SpHb may not be as accurate as clinically necessary in some patients," the authors write.
One author disclosed a financial relationship with Masimo, which provided the materials for the study.