Comparison of the accuracy of noninvasive hemoglobin monitoring for preoperative evaluation between adult and pediatric patients: a retrospective study.

Abstract

We measured noninvasive hemoglobin (SpHb) levels during the pre-anesthesia visit in patients planning elective surgery. Differences between SpHb and laboratory-measured hemoglobin (Hblab) were compared between adult and pediatric patients. In the pre-anesthesia visiting office, we routinely monitor noninvasive Hb levels with oxygen saturation and heart rate using Masimo Radical-7® Pulse CO-Oximetry (Masimo Corp., Irvine, CA, USA). We attached the R1 20 (body weight, 10-50kg) or R1 25 (body weight > 30kg) probe on the index finger. After signal stabilization, SpHb and perfusion index (PI) were recorded. We retrospectively reviewed the recorded data and included patients who visited the anesthesiologist within 24h after venous sampling. Bias was calculated by subtracting Hblab from SpHb. We compared the biases of adult and pediatric patients (< 18years) and evaluated correlation coefficients between the bias and Hblab. Records of 105 patients were reviewed and 100 data points of 50 patients in each group were analyzed. The median ± interquartile range bias was - 2.6 ± 2.2 and - 1.2 ± 1.5g/dL in adult and pediatric patients, respectively (P < 0.001); the corresponding mean ± standard deviation PIs were 4.4 ± 3.1 and 5.9 ± 2.7, respectively (P = 0.19). Bias was inversely proportional to Hblab irrespective of age. The correlation coefficient between the bias and Hblab was - 0.81 in adults and - 0.54 in pediatric patients (P < 0.001). SpHb and Hblab measured during pre-anesthesia visits showed a smaller difference in pediatric than in adult patients. Lower Hblab corresponded to higher accuracy.