SpHb Monitoring Research Articles

Noninvasive hemoglobin monitoring for maintaining hemoglobin concentration within the target range during major noncardiac surgery: A randomized controlled trial

Study objectiveThe effect of noninvasive CO-oximetry hemoglobin (SpHb) monitoring on the clinical outcomes of patients undergoing surgery remains unclear. This trial aimed to evaluate whether SpHb monitoring helps maintain hemoglobin levels within a predefined target range during major noncardiac surgeries with a potential risk of intraoperative hemorrhage. DesignA single-center, prospective, randomized controlled trial. SettingUniversity hospital. PatientsOne hundred and thirty patients undergoing elective noncardiac surgery with a potential risk of hemorrhage. InterventionsPatients were randomly allocated to undergo either SpHb-guided management (SpHb group) or usual care (control group). MeasurementsThe primary outcome was the rate of deviation of the total hemoglobin concentration (determined from laboratory testing) from a pre-specified target range (8–14 g/dL). This was defined as the number of laboratory tests revealing such deviations divided by the total number of laboratory tests performed during the surgery. Main resultsThe primary outcome occurred significantly less frequently in the SpHb group as compared to that in the control group (15/555 [2.7%]) vs. 68/598 [11.4%]; relative risk, 0.24; 95% confidence interval, 0.13–0.41; P < 0.001). Fewer point-of-care blood tests were performed in the SpHb group than in the control group (median [interquartile range], 2 [1–4] vs. 4 [2–5]; P < 0.001). There were no significant intergroup differences in the number of patients who received red blood cell transfusions during surgery (SpHb vs. control, 33.8% vs. 46.2%; P = 0.201). The incidence of unnecessary red blood cell preparation (>2 units) was lower in the SpHb group than in the control group (3.1% vs. 16.9%; P = 0.024). ConclusionsCompared with routine care, SpHb-guided management resulted in significantly lower rates of hemoglobin deviation outside the target range intraoperatively in patients undergoing major noncardiac surgeries with a potential risk of hemorrhage. Clinical trial registrationClinicalTrials.gov (identifier: NCT03816514).

Noninvasive continuous hemoglobin monitoring of blood transfusion in obstetric procedures

ABSTRACT Background Non-invasive Hb (SpHb) may allow for a faster detection of clinically important blood loss, improve perioperative transfusion practices significantly and enable a faster evaluation of a patient’s condition and a better blood treatment and may even reduce needless transfusions. This study determined the accuracy of continuous SpHb monitoring as a guide for fluid and blood transfusion practice using Masimo pulse co-oximetry in comparison with invasive Hb during elective cesarean section (CS). Methods This prospective cohort study was carried out on 60 pregnant women candidates for elective CS under general anesthesia. Participants were multigravida, aged between 18 and 45 years and carry a singleton fetus with ASA I–II. All had antepartum hemorrhage and were candidates for blood transfusion. Pre-induction of anesthesia (basal), pre-transfusion and post-transfusion SpHb and invasive Hb were assessed. The primary outcome parameter was the correlation between SpHb and invasive hemoglobin (Hb). Results There was a significant positive correlation between SpHb and Invasive Hb in baseline, pretransfusion and posttransfusion (r = 0.946, 0.902 and 0.698, respectively). Bland–Altman analysis between SpHb and invasive Hb reported low bias with moderate limits of agreement at baseline, pre-transfusion and post-transfusion [mean bias (limits of agreement): 0.348 (−0.584 and 1.280) g/dl, 0.314 (−0.561 and 1.188) g/dl and 0.348 (−0.584 and 1.280) g/dl, respectively] Conclusions In patients undergoing CS with antepartum hemorrhage, continuous SpHb through Masimo pulse co–oximetry demonstrated clinically acceptable accuracy of Hb measurement compared with Invasive Hb, even at low hemoglobin levels.

The effects of body weight and pneumoperitoneum on pleth variability index and total haemoglobin in patients undergoing laparoscopic cholecystectomy: A prospective observational study

It is not clear if there is an inaccurate effect of obesity and pneumoperitoneum on non-invasive monitoring parameters. The aim of this study is to determine the effects of CO2 pneumoperitoneum and desufflation on non-invasive monitoring variables between obese and non-obese patients undergoing laparoscopic surgery. Sixty patients were included in the study that underwent laparoscopic cholecystectomy between February 2019 and November 2019. After induction of anaesthesia, systolic and diastolic blood pressures, heart rate, duration of operation and pneumoperitoneum, pleth variability index (PVI) and total hemoglobin (SpHb) data were recorded. The patients were divided into two groups. There was no significant difference between the groups in terms of chronic diseases and duration of operation and pneumoperitoneum. No significant difference was found between the groups in PVI and SpHb values. In comparison of PVI measurement values with T0, a significant difference was found in T3, T4 and T5 in Group 2 (p = 0.010, 0.012 and 0.041, respectively). In comparison of SpHb measurement values with T0, a significant difference was found in T1, T2 and T3 in Group 2 (p = 0.008, 0.010 and 0.037, respectively). In comparison with T5, a significant difference was found in T1, T2 and T3 in Group 2 (p = 0.023, 0.005 and 0.006, respectively). In obese people, pneumoperitoneum can lead to errors in PVI and SpHb monitoring. Although these two parameters are very valuable in intraoperative follow-up, they should be used carefully during laparoscopic procedures in obese patients. If these parameters (PVI and SpHb) are considered to be used in bariatric surgeries, this information should be considered.

Continuous hemoglobin measurement during frontal advancement operations can improve patient outcomes.

Massive hemorrhage in pediatric cranioplasty operations may necessitate blood transfusion, which may cause many complications. Radical-7 Pulse CO-Oximeter (Massimo Corporation, Irvine, CA) can provide continuous hemoglobin concentration (SpHb) measurements noninvasively. In this study, we aimed to evaluate the effects of SpHb measurement on perioperative transfusion management and postoperative patient outcomes. For this retrospective case-control study, we collected the data of pediatric patients undergoing fronto-orbital advancement surgery for plagiocephaly and trigonocephaly between 2018 and 2021. Perioperative SpHb monitoring was performed for patients in the SpHb Group. Other patients that were managed conventionally were considered as the control group (C Group). The data on patients' demographic and clinical characteristics, intraoperative hemodynamic and laboratory variables such as blood gases, intraoperative blood losses, the amount of the transfused blood products, the length of postoperative intensive care unit (ICU) stay, and the duration of hospital stay were collected. The data of 42 patients were collected, and 29 of these patients were males (69%). In 16 of the patients, SpHb monitoring was performed. The demographic, clinical, and perioperative hemodynamic characteristics of the patients were comparable between the groups. Compared to the C Group, the SpHb Group had significantly lower perioperative packed red blood cell (PRBC) transfusion (136.3 ± 40.1 vs. 181.5 ± 74.8mL, P = 0.015), less postoperative drainage (125.3 ± 47.7 vs. 185.8 ± 97.6mL, P = 0.013), and shorter ICU stay (37.1 ± 12.0 vs. 64.8 ± 24.9h, P < 0.001). There was a positive correlation between the amount of PRBC transfusion and the length of ICU stay (r = 0.459, P = 0.003). Patients with perioperative continuous SpHb measurement have lower intraoperative PRBC transfusion, less postoperative bleeding, and shorter ICU stay. When necessary, SpHb, together with clinical judgment and laboratory confirmation, can be used in decision-making for perioperative PRBC transfusion.

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

IntroductionPostoperative nadir hemoglobin (Hb) is related to a longer length of stay for geriatric patients undergoing orthopedic surgery. We investigated whether postoperative pulse Hb (SpHb) measurement is useful for avoiding anemia and inappropriate blood transfusion after total hip arthroplasty and total knee arthroplasty.Material and MethodsThis prospective randomized controlled study included 150 patients randomly assigned to receive blood transfusion, either guided by SpHb monitoring (SpHb group) or based on the surgeons’ experience (control group). The target laboratory Hb value was set to >8 g/dL at postoperative day 1 (POD1). The primary endpoints were the product of total time and degree of SpHb <8 g/dL (area under SpHb 8 g/dL) during the period up to POD1 and the incidence of laboratory Hb <8 g/dL at POD1. The secondary endpoints were the amount of blood transfusion and inappropriate blood transfusion, which was defined as allogeneic blood transfusion unnecessary in a case of SpHb >12 g/dL or delayed transfusion in a case of SpHb <8 g/dL.ResultsThe area under SpHb 8 g/dL was 37.6 ± 44.1 g/dL-min (5 patients) in the control group and none in the SpHb group (P = .0281). There was 1 patient with Hb <8 g/dL at POD1 in the control group. There was no difference in laboratory Hb levels and the amount of blood transfusion. Forty-one patients (19 in the control group and 22 in the SpHb group) received an allogeneic blood transfusion. Among these patients, 7 in the control group and none in the SpHb group received inappropriate blood transfusion (P = .0022).DiscussionThe SpHb monitoring could reduce unnoticed anemia, which may prevent complications and be useful in avoiding unnecessary and excessive blood transfusion.ConclusionPostoperative SpHb monitoring decreased the incidence of transient, unnoticed anemia during the period up to POD1 and inappropriate blood transfusion.

Blood transfusion decisions cannot be based on percutaneous haemoglobin measurements.

Percutaneous measurement of haemoglobin (SpHb) has been an emerging technique in the past decades. It has been suggested that SpHb measurement could be used as atrend monitor and as asupportive tool for easier and faster transfusion decision-making. The aim of this study was to investigate whether SpHb monitoring is auseful instrument in transfusion decision-making. Patients scheduled for surgery with expected blood loss over 800 mL were included in the study. SpHb was measured using aMasimo Rainbow probe. Blood samples were drawn before and after surgery and, if clinically indicated, during surgery. Moreover, perfusion parameters were analysed, as well as transfusion triggers. Based on transfusion triggers 27.1% of patients would not have been transfused according to National Guidelines (14.5% transfused in error, 12.5% not transfused when indicated). Invasive haemoglobin (invasive Hb) and SpHb were obtained 266 times in 75 patients. The mean invasive Hb was 7.37 ± 1.34 mmol L-1 and SpHb was 6.47 ± 0.81 mmol L-1 (P < 0.001). Bland-Altman analysis corrected for multiple measurements revealed proportional bias of -4.05 + 0.72 Hb (least bias at Hb 5.62). The precision of the SpHb measurement exceeded the acceptable range of error. We concluded that SpHb measurement using the Rainbow device is too unreliable to be an acceptable alternative to invasive Hb measurement, or even as atrend monitor or decision support tool.

Non-invasive haemoglobin measurement among pregnant women using photoplethysmography and machine learning

Estimation of haemoglobin(Hb) using non-invasive methods has caught wide interest among researchers all over the globe. Among the various devices and methods adopted for non-invasive haemoglobin (SpHb) measurement, prediction of SpHb using PPG can provide earlier and faster diagnosis. The primary objective and motivation of this study is to assess the efficiency and effectiveness of SpHb monitoring among pregnant women using PPG and generalized linear regression technique. PPG signal was acquired from pregnant women with prior consent and Hb was predicted from the time-domain attributes of PPG. Hb value as calculated by the invasive lab methods was compared with the predicted SpHb value. The absolute bias between the SpHb predicted and Hbref was 0.73 g/dL (SD 0.62). To analyse and evaluate the performance of the proposed word, correlation coefficient between SpHb and Hblab, was calculated using IBM SPSS software.

Intraoperative continuous noninvasive hemoglobin monitoring in patients with placenta previa undergoing cesarean section: a prospective observational study.

BackgroundObstetric patients with placenta previa are at risk for sever peripartum hemorrhage. Early detection of anemia and proper transfusion strategy are important for the management of obstetric hemorrhage. In this study, we assessed the utility and accuracy of noninvasive hemoglobin (SpHb) monitoring in patients with placenta previa during cesarean section.MethodsParturients diagnosed with placenta previa and scheduled for cesarean section under spinal anesthesia were enrolled. SpHb and laboratory Hb (Lab-Hb) were measured during surgery as primary outcomes.ResultsSeventy-four pairs of SpHb and Lab-Hb were collected from 39 patients. The correlation coefficient was 0.877 between SpHb and Lab-Hb (P < 0.001). The Bland–Altman plot showed a mean difference ± SD of 0.3 ± 0.8 g/dl between noninvasive Hb and Lab-Hb, and the limits of agreement were −1.2 to 1.8 g/dl. The magnitude of the difference between SpHb and Lab-Hb was < 0.5 g/dl in 64.9%; however, it was > 1.5 g/dl in 10.8%.ConclusionsSpHb monitoring had a good correlation with Lab-Hb. A small mean difference between SpHb and lab-Hb might not be clinically significant; however, the limits of agreements were not narrow. In particular, SpHb could be overestimated in the anemic population. Based on our results, further studies investigating the accuracy and precision of SpHb monitoring should be performed in parturients presenting Hb below 10 g/dl.

Evaluation of Non-Invasive Measurement of Haemoglobin using PPG in Clinically Ill Pediatric Patients

Non-invasive haemoglobin (SpHb) estimation using Photoplethysmograph signal has gained enormous attention among researches in order to provide an earlydiagnosis to polycythemia, anaemia, various cardiovascular diseases, etc. The primary objective of this work is to evaluate the performance efficiency of SpHb monitoring using PPG in clinically ill pediatric population. PPG signal was obtained from the pediatric patients, and SpHb was calculated from the characteristic features of PPG. Haemoglobin value obtained through venous blood sample was compared with SpHb. Theabsolute mean difference between the SpHb and Hbref was 0.78g/dL (SD 0.99; 0.1 to 4.1).For a statistical analysis of the correlation between SpHb and Hblab, IBM SPSS statistics software was used. Bland-Altman analysis, T-test and Linear regression analysis were further used for finding the agreeability limits. Overestimation of SpHb value was observed for lower Hblab values, and SpHb failed to detect anaemic subjects.

Continuous noninvasive hemoglobin monitoring estimates timing for detecting anemia better than clinicians: a randomized controlled trial

BackgroundHemoglobin measurement is important for transfusion decision-making. Pulse CO-Oximetry provides real-time continuous hemoglobin (SpHb) monitoring. The triage role of SpHb trends based on hemoglobin measurements was investigated.MethodsIn this diagnostic randomized controlled trial, 69 patients undergoing spine or cytoreductive surgery were randomly enrolled into SpHb-monitoring and standard-care groups. Diagnostic blood samples were drawn for CO-oximetry Hb (CoOxHb) when the SpHb decreased by 1 g/dl or at the clinician’s discretion in the standard-care group. The positive predictive value (PPV) was defined as the ability to detect a decrease in CoOxHb > 1 g/dl or a CoOxHb < 10 g/dl; the PPVs were compared using Fisher’s exact test. The SpHb and trend accuracies were calculated. The transfusion units and postoperative hemoglobin levels were compared.ResultsThe PPV of a decrease in CoOxHb > 1 g/dl was 93.3% in the SpHb group vs 54.5% without SpHb monitoring (p = 0.002). The PPV of CoOxHb < 10 g/dl was 86.7% vs. 50.0% for these groups (p = 0.015). The CoOxHb was never < 7 g/dl with SpHb monitoring. Sixty SpHb–CoOxHb data pairs and 28 delta pairs (ΔSpHb-ΔCoOxHb) were collected. The bias, precision and limits of agreement were − 0.29, 1.03 and − 2.30 to 1.72 g/dl, respectively. When ΔSpHb and ΔCoOxHb were > 1 g/dl, the concordance rate for changes in hemoglobin reached 100%. The delta pairs revealed a positive correlation [ΔSpHb = 0.49 * ΔCoOxHb - 0.13; r = 0.69, 95% confidence interval (0.53, 0.82)]. No significant differences were found in the transfusion volume or postoperative anemia state.ConclusionsThe SpHb trend tracked changes in hemoglobin satisfactorily during surgery and more accurately estimated the appropriate timing for invasive hemoglobin measurements than the clinicians.Trial registrationChiCTR1800016290 (Prospective registered). Initial registration date was 24/05/2018.

Utility of non-invasive haemoglobin monitoring in oncosurgery patients.

Background and Aims:Oncosurgeries may incur massive blood loss demanding frequent blood sampling to assess blood loss and the need for intraoperative blood transfusions. Accuracy of non-invasive spectrophotometric haemoglobin (hereafter to be referred as SpHb) monitoring has been studied in various perioperative settings. The intraoperative use of Radical-7®, Masimo Corp., (Radical-7®) for SpHb monitoring may be useful during cancer surgery. The aim of this study is to evaluate the intraoperative utility of SpHb monitoring by the Radical-7® to guide intraoperative transfusion in oncosurgeries.Methods:Fifty adult patients, undergoing oncosurgery with anticipated blood loss of more than 20% of blood volume, were selected. Continuous SpHb monitoring was performed intraoperatively and blood transfusion was based on SpHb values. Simultaneous laboratory haemoglobin (LabHb) samples were taken for validation. The accuracy of intraoperative blood transfusions based on SpHb was analysed using Error Grid Analysis. Paired measurements of SpHb and LabHb were compared using Bland–Altman plot analysis.Results:There were 66 paired data points for blood transfusion from fifty patients with a correlation of 73% (P < 0.001) between SpHb and LabHb. In the Bland–Altman analysis, the bias was − 0.313 g/dl with ~ 95% of values within the limits of agreement of 1.81 g/dl to −2.44 g/dl. In the Error Grid Analysis, most data points were in the least error zone (Zone A).Conclusion:The Radical-7® has the advantage of providing SpHb value continuously to take prompt decision regarding blood transfusion intraoperatively.

The Value of Continuous Noninvasive Hemoglobin Monitoring in Intraoperative Blood Transfusion Practice during Abdominal Cancer Surgery

Introduction: Patients undergoing major oncological surgery may suffer from severe bleeding. Sometimes, it is difficult to anesthesiologist to take decision about timing of administration blood products to such patients. The aim of this study is to evaluate the use of continuous noninvasive hemoglobin monitoring as a guide for blood transfusion practice. Methods: One hundred patients undergoing elective abdominal cancer surgeries were randomly allocated into two groups, Group I (n = 50): laboratory Hb was obtained at baseline (immediate preoperative), intraoperative (when to suggest transfusion triggering value) and immediate postoperative. Group II (n = 50): The probe of Masimo for SpHb monitoring was applied immediately after induction of anesthesia at the index finger. Laboratory Hb was obtained at baseline (immediate preoperative), intraoperative (when to suggest transfusion triggering value) and immediate postoperative. Results: A number of transfused units of RBC were significantly lower in SpHb group than in control group (p value 0.05). Conclusion: SpHb monitoring had clinically acceptable absolute and trend accuracy. SpHb monitoring altered transfusion decision making and resulted in decreased RBC utilization and decreased RBC costs while facilitating earlier transfusions when indicated.

Accuracy of continuous noninvasive hemoglobin monitoring for the prediction of blood transfusions in trauma patients.

Early detection of hemorrhagic shock is required to facilitate prompt coordination of blood component therapy delivery to the bedside and to expedite performance of lifesaving interventions. Standard physical findings and vital signs are difficult to measure during the acute resuscitation stage, and these measures are often inaccurate until patients deteriorate to a state of decompensated shock. The aim of this study is to examine a severely injured trauma patient population to determine whether a noninvasive SpHb monitor can predict the need for urgent blood transfusion (universal donor or additional urgent blood transfusion) during the first 12 h of trauma patient resuscitation. We hypothesize that trends in continuous SpHb, combined with easily derived patient-specific factors, can identify the immediate need for transfusion in trauma patients. Subjects were enrolled if directly admitted to the trauma center, >17 years of age, and with a shock index (heart rate/systolic blood pressure) >0.62. Upon admission, a Masimo Radical-7 co-oximeter sensor (Masimo Corporation, Irvine, CA) was applied, providing measurement of continuous non-invasive hemoglobin (SpHb) levels. Blood was drawn and hemoglobin concentration analyzed and conventional pulse oximetry photopletysmograph signals were continuously recorded. Demographic information and both prehospital and admission vital signs were collected. The primary outcome was transfusion of at least one unit of packed red blood cells within 24 h of admission. Eight regression models (C1-C8) were evaluated for the prediction of blood use by comparing area under receiver operating curve (AUROC) at different time intervals after admission. 711 subjects had continuous vital signs waveforms available, to include heart rate (HR), SpHb and SpO2 trends. When SpHb was monitored for 15 min, SpHb did not increase AUROC for prediction of transfusion. The highest ROC was recorded for model C8 (age, sex, prehospital shock index, admission HR, SpHb and SpO2) for the prediction of blood products within the first 3 h of admission. When data from 15 min of continuous monitoring were analyzed, significant improvement in AUROC occurred as more variables were added to the model; however, the addition of SpHb to any of the models did not improve AUROC significantly for prediction of blood use within the first 3 h of admission in comparison to analysis of conventional oximetry features. The results demonstrate that SpHb monitoring, accompanied by continuous vital signs data and adjusted for age and sex, has good accuracy for the prediction of need for transfusion; however, as an independent variable, SpHb did not enhance predictive models in comparison to use of features extracted from conventional pulse oximetry. Nor was shock index better than conventional oximetry at discriminating hemorrhaging and prediction of casualties receiving blood. In this population of trauma patients, noninvasive SpHb monitoring, including both trends and absolute values, did not enhance the ability to predict the need for blood transfusion.

Continuous Noninvasive Hemoglobin Monitoring: A Measured Response to a Critical Review.

The measurement of hemoglobin concentration in the blood (Hb) plays a central role in the detection, evaluation, and management of chronic and acute anemia. The gold standard for laboratory determination of Hb is hemoglobin cyanide (HiCN).1 HiCN testing is not routinely used in hospitals due to its complexity, so cyanide-free central laboratory hematology analyzers (e.g., Coulter, Sysmex) have become the clinical standard.2 It is tempting to assume that satellite CO-Oximeters (e.g., ABL, Radiometer, Denmark; Nova, Nova Biomedical, Waltham, MA) used for arterial blood gas measurement in the operating room or critical care unit are interchangeable with hematology analyzers, but in fact they are not. Pulse CO-Oximetry is the multiwavelength technology contained in the first devices to have received Food and Drug Administration 510(k) clearance for the continuous, noninvasive monitoring of total hemoglobin (SpHb; Masimo, Irvine, CA). Generally speaking, SpHb monitoring is not yet as accurate as laboratory hemoglobin (lab-Hb), and it is therefore not intended today as a replacement for lab-Hb. The focus should instead be on the value-added benefits of supplementing intermittent, delayed lab-Hb values with continuous, real-time visibility of whether Hb is stable, increasing, or decreasing. The purpose of this article is to provide a perspective on the appropriate role and evaluation of SpHb and the value-added benefits of continuous Hb monitoring. We offer an alternative viewpoint to balance the 3 separate but similar opinions published earlier in Anesthesia & Analgesia by Drs. Rice, Gravenstein, and Morey.3–5 These authors propose “what is required of a noninvasive hemoglobin monitor and whether the conventional statistics adequately answer our questions about clinical accuracy.” In doing so, Rice et al. concluded that the accuracy of SpHb monitoring “is not good enough to make the (a) transfusion decision.” In the present article, clinical advisors to Masimo Corporation respond to these evaluations with a measured perspective on the value-added clinical decision process that this technology will bring to patient management and safety. It is also time to review and reassess the fundamental assumptions regarding lab-Hb and its use in making clinical decisions. Given that it is noninvasive and its ability to provide continuous, real-time data that can be correlated at bedside with events happening to the patient, SpHb monitoring offers a new paradigm and opens up new possibilities for improved patient care.

Continuous Non-invasive Hemoglobin Monitoring during Orthopedic Surgery: A Randomized Trial

Blood transfusions during orthopedic surgery increase the risk of adverse outcomes and are costly. In current practice, laboratory hemoglobin values are used to determine the need for blood transfusion, but testing is intermittent. We hypothesized that continuous non-invasive hemoglobin monitoring (SpHb) could reduce intraoperative blood transfusions. Patients undergoing elective orthopedic surgery were randomized to receive standard care alone or standard care with SpHb monitoring. Of the 327 patients enrolled (170 intervention, 157 control), 0.6% received intraoperative transfusions in the intervention group compared to 4.5% in the control group, for an absolute risk reduction of 4% (95% CI: -7% to -0.4%). The amount of red blood cell units transfused did not differ between the groups, nor did the rate of laboratory hemoglobin testing. The use of continuous noninvasive hemoglobin monitoring may reduce the rate of transfusions when compared to standard care using intermittent laboratory hemoglobin testing.

1665 Noninvasive Monitoring of Hemoglobin Concentration in Pediatric Cardiac Postoperative Patients

Background/AimOne of the major concerns after cardiovascular surgery is to detect bleeding and optimize hemoglobin (Hb) to improve cardiac output, leading to repeated blood tests. We describe our experience with...

Validation of continuous and noninvasive hemoglobin monitoring by pulse CO-oximetry in Japanese surgical patients

We evaluated the accuracy of noninvasive and continuous total hemoglobin (SpHb) monitoring with the Radical-7(®) Pulse CO-Oximeter in Japanese surgical patients before and after an in vivo adjustment of the first SpHb value to match the first reference value from a satellite laboratory CO-Oximeter. Twenty patients undergoing surgical procedures with general anesthesia were monitored with Pulse CO-Oximetry for SpHb. Laboratory CO-Oximeter values (tHb) were compared to SpHb at the time of the blood draws. Bias, precision, limits of agreement and correlation coefficient of SpHb compared to tHb were calculated before and after SpHb values were adjusted by subtracting the difference between the first SpHb and tHb value from all subsequent SpHb values. Trending of SpHb to tHb and the effect of perfusion index (PI) on the agreement of SpHb to tHb were also analyzed. Ninety-two tHb values were compared to the SpHb. Bias ± 1SD was 0.2 ± 1.5 g/dL before in vivo adjustment and -0.7 ± 1.0 g/dL after in vivo adjustment. Bland-Altman analysis showed limits of agreement of -2.8 to 3.1 g/dL before in vivo adjustment and -2.8 to 1.4 g/dL after in vivo adjustment. The correlation coefficient was 0.76 prior to in vivo adjustment and 0.87 after in vivo adjustment. In patients with adequate perfusion (PI ≥1.4) the correlation coefficient was 0.89. In vivo adjustment of SpHb significantly improved the accuracy in our cohort of Japanese surgical patients. The strongest correlation between SpHb and tHb values was observed in patients with adequate peripheral perfusion suggesting that low perfusion may affect the accuracy of SpHb monitoring.

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.

Non-invasive measurement of hemoglobin during cesarean hysterectomy: a case series

Obstetric patients diagnosed with abnormal placentation (placenta accreta, increta or percreta) are at increased risk of major postpartum hemorrhage and cesarean hysterectomy. Obstetric anesthesiologists are primarily involved in intraoperative transfusion management in these cases. Hemoglobin assessment is invaluable for assisting transfusion decision-making during the acute period of obstetric hemorrhage. However, laboratory and point-of-care tests of hemoglobin concentration are time-dependent and intermittent, and do not provide a real-time assessment of change during the acute phase of blood loss. A new non-invasive hemoglobin monitor has been introduced recently, which provides real-time measurement of hemoglobin values (SpHb) using multi-wavelength pulse co-oximetry. We present a review of five patients with suspected abnormal placentation who received SpHb monitoring during cesarean hysterectomy at our institution. We discuss the potential clinical utility of non-invasive hemoglobin monitoring for pregnant patients at high risk of obstetric hemorrhage, and the potential role of SpHb in guiding transfusion therapy.

The Effectiveness and Limit of SpHb Monitoring on Perioperative Management

周術期出血は有害事象発症の重大原因であるが，近年，出血の主要な治療法である輸血それ自体も，有害事象発症と関連性があることが報告されている．術中出血に対する時宜を得た適切な輸液・輸血管理と不必要な輸血の回避が，手術患者の予後を改善すると思われる．従来，麻酔科医は周術期のヘモグロビン（Hb）濃度を測定し，手術患者の貧血度と酸素輸送量を推定してきた．さらに，術中大量出血時は，組織への酸素供給量を維持する上で，Hb濃度の測定とともに循環血液量不足の検出が必要となる．近年，マシモ社が開発したパルスCOオキシメトリは全ヘモグロビン（SpHbTM）値と新しい輸液反応指標である脈波変動指標（PVI ®）の連続的な測定を可能にした．今回は，SpHbモニターの信頼性とともに，SpHbとPVIの同時モニタリングが周術期循環管理にもたらす有効性と限界について述べる．