Accuracy Of Noninvasive Hemoglobin Monitoring Research Articles

Accuracy of non-invasive hemoglobin monitoring by pulse CO-oximeter during hepatectomy in living liver donors

Accuracy of non-invasive hemoglobin monitoring by pulse CO-oximeter during hepatectomy in living liver donors

Accuracy of non-invasive hemoglobin monitoring by pulse CO-oximeter during liver transplantation.

Hemoglobin level monitoring is essential during liver transplantation (LT) due to substantial blood loss. We evaluated the accuracy of non-invasive and continuous hemoglobin monitoring (SpHb) obtained by a transcutaneous spectrophotometry-based technology (Masimo Corporation, Irvine, CA) compared with conventional laboratory Hb measurement (HbL) during LT. Additionally, we made subgroup analyses for distinct surgical phases that have special features and hemodynamic problems and thus may affect the accuracy of SpHb. During LT, blood samples were obtained twice for each of the three phases of LT (pre-anhepatic, anhepatic, and neohepatic) and were analyzed by the central laboratory. The HbL measurements were compared with SpHb obtained at the time of the blood draws. A total of 282 data pairs obtained from 53 patients were analyzed. The SpHb values ranged from 6.9 to 17.7 g/dL, and the HbL values ranged from 5.4 to 17.1 g/dL. The correlation coefficient between SpHb and HbL was 0.73 (P<0.001), and change in SpHb versus change in HbL was 0.76 (P<0.001). The sensitivity value determined using a 4-quadrant plot was 79%. The bias and precision of SpHb to HbL were 0.86±1.58 g/dL; the limits of agreement were -2.25 to 3.96 g/dL. The overall correlation between SpHb and HbL remained stable in different phases of surgical procedure. SpHb was demonstrated to have a clinically acceptable accuracy of hemoglobin measurement in comparison with a standard laboratory device when used during LT. This technology can be useful as a trend monitor during all surgical phases of LT and can supplement HbL to optimize transfusion decisions or to detect occult bleeding.

Trending and accuracy of noninvasive hemoglobin monitoring in pediatric perioperative patients.

Rainbow Pulse CO-Oximetry technology (Masimo Corporation, Irvine, CA) provides continuous and noninvasive measurement of arterial hemoglobin concentration (SpHb). We assessed the trending and accuracy of SpHb by this innovative monitoring compared with Hb concentration obtained with conventional laboratory techniques (Hb) in children undergoing surgical procedures with potential for substantial blood loss. Hb concentrations were recorded from Pulse CO-Oximetry and a conventional hematology analyzer. Regression analysis and 4-quadrant plot were used to evaluate the trending for changes in SpHb and Hb measurements (ΔSpHb and ΔHb). Bias, precision, and limits of agreement of SpHb and of in vivo adjusted SpHb (SpHb - first bias to HB) compared with Hb were calculated. One hundred fifty-eight SpHb-Hb data pairs and 105 delta pairs (ΔSpHb and ΔHb) from 46 patients aged 2 months to 17 years with Hb ranging from 16.7 to 7.9 g/dL were collected. To evaluate trending, the delta pairs (ΔSpHb and ΔHb) were plotted, which revealed a positive correlation (ΔSpHb = 0.022 + 0.76ΔHb) with correlation coefficient r = 0.76, 95% CI [confidence interval] = 0.57-0.86. The bias and precision of SpHb to Hb and in vivo adjusted SpHb were 0.4 ± 1.3 g/dL and 0.1 ± 1.2 g/dL, respectively; the limits of agreement were -2.0 to 3.2 g/dL before in vivo adjustment and -2.4 to 2.2 g/dL after in vivo adjustment (P value = 0.04). The mean percent bias (from the reference Hb concentration) decreased from 4.1% ± 11.9% to 0.7% ± 11.3% (P value = 0.01). No drift in bias over time was observed during the study procedure. Of patient demographic and physiological factors tested for correlation with the SpHb, only perfusion index at sensor site showed a weak correlation. The accuracy of SpHb in children with normal Hb and mild anemia is similar to that previously reported in adults and is independent of patient demographic and physiological states except for a weak correlation with perfusion index. The trending of SpHb and Hb in children with normal Hb and mild anemia showed a positive correlation. Further studies are necessary in children with moderate and severe anemia.

To Stick or Not to Stick? Accuracy of Non-Invasive Hemoglobin Monitoring in Patients with Suspected Hemorrhage

To Stick or Not to Stick? Accuracy of Non-Invasive Hemoglobin Monitoring in Patients with Suspected Hemorrhage

Influence of peripheral perfusion index on accuracy of noninvasive hemoglobin monitoring (SpHb)

Influence of peripheral perfusion index on accuracy of noninvasive hemoglobin monitoring (SpHb)

The Accuracy of Noninvasive Hemoglobin Monitoring Using the Radical-7 Pulse CO-Oximeter in Children Undergoing Neurosurgery

The most common method for determining the hemoglobin concentration is to draw blood from a patient. However, the Radical-7 Pulse CO-Oximeter (Masimo Corporation, Irvine, CA) can noninvasively provide continuous hemoglobin concentration (SpHb). In our study we compared noninvasive measurements of SpHb with simultaneous laboratory measurements of total hemoglobin in arterial blood samples taken from children (tHb). Arterial blood samples were analyzed using a laboratory CO-oximeter, and SpHb was simultaneously recorded in pediatric patients undergoing neurosurgery. When patients met the criteria for hypovolemia, 10 mL/kg of colloids or red blood cells were administered over 10 minutes. SpHb and tHb data were collected before and after intravascular volume resuscitation. The relationship between SpHb and tHb was assessed using a 4-quadrant plot, linear regression, mixed-effect model, and modified Bland-Altman analyses. One hundred nineteen paired samples were analyzed. The correlation coefficient between SpHb and tHb was 0.53 (P < 0.001), whereas that of change in SpHb versus change in tHb was 0.75 (P < 0.001). The average difference (bias) between tHb and SpHb was 0.90 g/dL (95% confidence interval [CI], 0.48-1.32 g/dL) and 1 standard deviation of the difference (sd) was 1.35 g/dL. The concordance rate (a measure of the number of data points that are in 1 of the 2 quadrants of agreement) determined using a 4-quadrant plot was 93%. The correlation coefficient between SpHb and tHb after intravascular volume resuscitation was 0.58 (P < 0.001), whereas that of changes in SpHb and tHb was 0.87 (P < 0.001). The bias immediately after volume resuscitation was 1.18 g/dL (95% CI, 0.81-1.55 g/dL), and sd was 1.28 g/dL with a concordance rate of 94.4%. The bias was -0.03 g/dL when tHb was ≥11 g/dL, which was significantly lower in comparison with biases when tHb <9 g/dL (1.24 g/dL) and tHb was 9-11 g/dL (1.17 g/dL) (P = 0.004). The Radical-7 Pulse CO-Oximeter can be useful as a trend monitor in children during surgery even immediately after intravascular volume expanders are administered. However, it is advisable to confirm the baseline hemoglobin level and to consider the influence of tHb level on the bias. In addition, one should be cautious with regard to using SpHb alone when making transfusion decisions.

Does a digital regional nerve block improve the accuracy of noninvasive hemoglobin monitoring?

Blood hemoglobin (Hb) can be continuously monitored utilizing noninvasive spectrophotometric finger sensors (Masimo SpHb). SpHb is not a consistently accurate guide to transfusion decisions when compared with laboratory Co-Oximetry (tHb). We evaluated whether a finger digital nerve block (DNB) would increase perfusion and, thereby, improve the accuracy of SpHb. Twenty adult patients undergoing spinal surgery received a DNB with lidocaine to the finger used for the monitoring of SpHb. SpHb-tHb differences were determined immediately following the DNB and approximately every hour thereafter. These differences were compared with those in our previously reported patients (N=20) with no DNB. The SpHb-tHb difference was defined as "very accurate" if<0.5g/dL and "inaccurate" if>2.0g/dL. Perfusion index (PI) values at the time of each SpHb-tHb measurement were compared. There were 57 and 78 data points in this and our previous study, respectively. The presence of a DNB resulted in 37% of measurements having SpHb values in the "very accurate group" versus 12% in patients without a DNB. When the PI value was>2.0, only 1 of 57 DNB values was in the "inaccurate" group. The PI values were both higher and less variable in the patients who received a DNB. A DNB significantly increased the number of "very accurate" SpHb values and decreased the number of "inaccurate" values. We conclude that a DNB may facilitate the use of SpHb as a guide to transfusion decisions, particularly when the PI is>2.0.

Comparison of the Accuracy of Noninvasive Hemoglobin Monitoring by Spectrophotometry (SpHb) and HemoCue® with Automated Laboratory Hemoglobin Measurement

The reference method for hemoglobin concentration measurement remains automated analysis in the laboratory. Although point-of-care devices such as the HemoCue® 201+ (HemoCue, Ängelholm, Sweden) provide immediate hemoglobin values, a noninvasive, spectrophotometry-based technology (Radical-7®; Masimo Corp., Irvine, CA) that provides continuous online hemoglobin (SpHb) measurements has been introduced. This clinical study aimed to test the hypothesis that SpHb monitoring was equivalent to that of HemoCue® (the automated hemoglobin measurement in the laboratory taken as a reference method) during acute surgical hemorrhage. Blood for laboratory analysis was sampled after induction of anesthesia, during surgery according to the requirements of the anesthesiologist, and finally after the transfer of the patient to the recovery room. When each blood sample was taken, capillary samples were obtained for analysis with HemoCue®. SpHb monitoring was performed continuously during surgery. Using the automated hemoglobin measurement in the laboratory as a reference method, the authors tested the hypothesis that SpHb monitoring is equivalent to that of HemoCue®. The agreement between two methods was evaluated by linear regression and Bland and Altman analysis. Eighty-five simultaneous measurements from SpHb, HemoCue®, and the laboratory were obtained from 44 patients. Bland and Altman comparison of SpHb and HemoCue® with the laboratory measurement showed, respectively, bias of -0.02 ± 1.39 g · dl(-1) and -0.17 ± 1.05 g · dl(-1), and a precision of 1.11 ± 0.83 g · dl(-1) and 0.67 ± 0.83 g · dl(-1). Considering an acceptable difference of ± 1.0 g · dl(-1) with the laboratory measurement, the percentage of outliers was significantly higher for SpHb than for HemoCue® (46% vs. 16%, P < 0.05). Taking automated laboratory hemoglobin measurement as a reference, the study shows that SpHb monitoring with Radical-7® gives lower readings than does the HemoCue® for assessment of hemoglobin concentration during hemorrhagic surgery.