Available online at ScienceDirect. Procedia Engineering 132 (2015 )

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1 Available online at ScienceDirect Procedia Engineering 132 (2015 ) The Manufacturing Engineering Society International Conference, MESIC 2015 Continuous hemoglobin measurement procedure for more efficient blood transfusion management and associated savings B. Ribed-Sanchez a, *, C. Gonzalez-Gaya a, C.Corbacho-Fabregat b a Department of Manufacturing Engineering, ETSII-Universidad Nacional de Educación a Distancia (UNED), c/ Juan del Rosal 12, Madrid, Spain. b Department of Anesthesia. Hospital Universitario de Madrid Sanchinarro, c/ Oña 10, Madrid, Spain. Abstract Blood transfusions are costly and increase morbidity and mortality [1,2,3]. Transfusion decisions are guided by the value of hemoglobin in patients. The worldwide current practice of obtaining this data is based in intermittent, invasive measurements of hemoglobin that are sent to the laboratory. This procedure may contribute to unnecessary and inappropriate blood transfusions that account for 10% [4] of the total amount of transfusions, due to the uncertainty given by the delay in receiving the data back from the lab and the difficulty associated in the detection of internal bleeding. The use of a new procedure to obtain hemoglobin value, based in real-time monitoring, may allow physicians to initiate timely blood transfusions and avoid giving unnecessary ones. A literature search will be done to demonstrate a reduction in transfusions with this new monitoring method and the associated savings in costs Published The Authors. by Elsevier Published Ltd. by This Elsevier is an open Ltd. access article under the CC BY-NC-ND license ( Peer-review under responsibility of the Scientific Committee of MESIC Peer-review under responsibility of the Scientific Committee of MESIC 2015 Keywords: Sensor; correlation; cost-efficiency; hemoglobin. 1. Introduction Blood plays an important role in regulating the body's systems and maintaining homeostasis. It performs many functions within the body, including: * Corresponding author. Tel.: address: bribed1@alumno.uned.es Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license ( Peer-review under responsibility of the Scientific Committee of MESIC 2015 doi: /j.proeng

2 B. Ribed-Sanchez et al. / Procedia Engineering 132 ( 2015 ) Supplying oxygen to tissues (bound to hemoglobin, which is carried in red cells). Supplying nutrients bound to plasma proteins. Removing waste such as carbon dioxide, urea, and lactic acid. Messenger functions, including the transport of hormones and the signaling of tissue damage. The protein hemoglobin was discovered by Hünefeld in 1840, while the role of hemoglobin in the blood as an oxygen-carrying protein was elucidated by French physiologist Claude Bernard. Blood transfusion is generally the process of receiving blood products into one's circulation intravenously. Transfusions are used for various medical conditions to replace lost components of the blood. Early transfusions used whole blood, but modern medical practice commonly uses only components of the blood, such as red blood cells, white blood cells, plasma, clotting factors, and platelets. During surgical procedures bleeding is caused by the breaking of blood vessels. It is a necessary adverse effect, but some of the internal bleedings are difficult to detect and quantify. Continuous bleeding derives in a continuous reduction of the Hemoglobin value in patients. Transfusion decision-making is determined by this patient s hemoglobin value and when the hemoglobin reaches a certain low value, the transfusion is mandatory. While necessary, transfusions of blood products are associated with several complications, many of which can be grouped as immunological or infectious. While some complication risks depend on patient status or specific transfusion quantity involved, a baseline risk of complications simply increases in direct proportion to the frequency and volume of transfusion. As a resume, blood transfusions are costly and increase patient risk, morbidity and mortality that result from the diseases caused by the adverse secondary effects inherent in transfusions. This morbidity and mortality result in health and economic costs. Any new procedure or methodology that can reduce the number of unnecessary transfusions will derive in a better and more cost-efficient health system. 2. Current situation of obtaining Hemoglobin value in Hospitals. Hemoglobin concentration measurement is among the most commonly performed blood tests. Laboratory hemoglobin test methods require a blood sample and analysis on hematology analyzer. The current practice of obtaining the hemoglobin value of a patient during surgeries is based in two methods: 2.1. Analytical method: This method is based in intermittent, invasive measurements of hemoglobin that are sent to the laboratory. The laboratory, once processed the blood sample, sends to the operating room the analytical report. The value of the Hemoglobin is expressed in grams per deciliter (g/dl). In the analytical reports, hemoglobin is shown with the acronym of Hb Qualitative and Quantitative method: Based in their expertise, physicians calculate the amount of blood drawn in the reservoir during the surgery and translate the volume into g/dl, deducting that value to the prior hemoglobin value of the patient shown in the presurgical consultation. This current methodology may contribute to unnecessary and inappropriate blood transfusions that account for 10% [4] of the total amount of transfusions, due to the uncertainty given by the delay in receiving the data back from the lab between blood draw and laboratory analysis and the difficulty associated in the detection of internal bleeding. The use of a new procedure to obtain hemoglobin value, based in continuous monitoring and measurement, may allow physicians to initiate timely blood transfusions and avoid giving unnecessary ones.

3 162 B. Ribed-Sanchez et al. / Procedia Engineering 132 ( 2015 ) Furthermore, non-invasive and continuous hemoglobin monitoring provides real-time trends in the direction of Hb, such as indicating stable Hb when it may be perceived to be dropping and rising Hb when it may be perceived to not be rising fast enough. 3. Materials 3.1. The Rainbow Radical-7 Pulse CO-Oximeter Radical-7 is a non-invasive, arterial oxygen saturation, total haemoglobin concentration and pulse rate monitor. Fig 1. Rainbow Pulse CO-Oximetry with Total Hemoglobin (SpHb ) continuous Measurement. [5] It is indicated for the continuous, non-invasive monitoring of functional oxygen saturation of arterial hemoglobin (SpO2), pulse rate and total hemoglobin concentration expressed in grams per deciliter (SpHb). The principle of operation is as follows: Using spectrophotometry, oxyhemoglobin (oxygenated blood), deoxyhemoglobin (non-oxygenated blood), carboxyhemoglobin (blood with carbon monoxide content) and methemoglobin (blood with oxidized hemoglobin) differ in their absorption of visible and infrared light Fig 2. Absorption spectra of blood components

4 B. Ribed-Sanchez et al. / Procedia Engineering 132 ( 2015 ) The amount of arterial blood in tissue changes with your pulse (photoplethysmography). Therefore, the amount of light absorbed by the varying quantities of arterial blood changes as well The SpHb Sensor The Radical-7 utilizes a sensor with various light-emitting diodes, LEDs (number 1 in Figure 3) that pass light through the site to a diode (detector) (number 2 in Figure 3). Fig 3. Sensor technology Signal data is obtained by passing numerous visible and infrared lights (LEDs, 500 to 1400nm) through a capillary bed (for example, a fingertip, a hand, a foot) and determining and measuring changes in light absorption during the blood pulsatile cycle. The detector receives the light, converts it into an electronic signal and sends it to the Radical-7 for calculation. 4. Methods A literature search based on articles, texts, corporation webpages, encyclopedias and books of recent studies will be done to demonstrate: Quality of the sensor: To demonstrate the quality of the sensor, the correlation between sensor and laboratory analysis (current invasive universally used method) will be studied. Efficiency: Besides the medical improvement of obtaining additional real-time clinical values of the patients, the effectiveness of the new methodology is based on an expected reduction in blood transfusions when real-time monitoring of hemoglobin is used. Cost savings: Blood transfusions are costly (directly and indirectly by the increase of morbidity and mortality associated to them). Multiplying transfusions saved by this new method with the cost of each transfusion will show the economic savings of this procedure. 5. Results 5.1. Correlation. RADICAL-7 vs. Laboratory Analysis (drawn whole blood measurements) When SpHb (continuous hemoglobin monitoring) measurements obtained from the Radical-7 are compared to drawn whole blood (invasive) measurements by laboratory analytical methods, caution should be taken when evaluating and interpreting the results. The laboratory CO-Oximetry measurements may differ from the SpHb measurements of the Radical-7 Pulse CO-Oximeter. There are multiple studies of the correlation between both methods. Good correlation in this clinical parameter should be less than 1.5 g/dl. All studies where made using Masimo Radical-7 Pulse CO-Oximeter, in voluntary adult patients: Masimo technical bulletin 1 [6]: In 11,335 comparisons of SpHb and invasive hemoglobin (thb) measurements from a laboratory reference device, SpHb accuracy was g/dl. bias and 0.99 g/dl. at one standard deviation.

5 164 B. Ribed-Sanchez et al. / Procedia Engineering 132 ( 2015 ) Fig 4. Normal Sensitivity Scatter Plot of SpHb Vs thb measurements [6] Frasca and Mimoz study [7]: In 471 comparisons of SpHb and invasive hemoglobin (thb) measurements from a laboratory reference device, the bias and limits of agreement were 0.0 ± 1.0g/dL for the Pulse CO-Oximeter. Masimo Technical Bulletin 2 [8]: In 492 comparisons of SpHb readings with invasive hemoglobin (thb) measurements taken at the same time and analyzed by a laboratory CO-Oximeter, SpHb had a correlation of 0.90, a standard deviation of 0.95 g/dl. Berkow and colleagues [9]: An investigation of the accuracy of SpHb compared to laboratory CO-Oximetry measurement of 130 arterial blood samples from 29 complex spine surgery patients showed a bias and precision (defined as 1 SD of the bias) of -0.1 g/dl. ± 1.0 g/dl. Lamhaut et al. [10] obtained a total of 85 measurements, which showed a bias of only 0.02 g/dl. (SD 1.39) and a precision of 1.11 g/dl. (SD 0.83) Reduction in transfusions Once observed the correlation between both methods of obtaining Hemoglobin values, there are several studies in which the reduction of the total amount of transfusions is analyzed: Awada & Maher study [4]: A total of 106 orthopaedic patients were enrolled a prospective cohort study at an academic, tertiary hospital. The study showed a 10% reduction in blood transfusions (from 49% to 44%) as follows: Table 1. Blood transfusions in Awada study [4] Standard Care Group Patients Transfused (N) Transfused (N) 49% 44% SpHb Group

6 B. Ribed-Sanchez et al. / Procedia Engineering 132 ( 2015 ) Ehrenfeld, Henneman & Sangber study [11]: A total of 327 patients were enrolled (157 standard care, 170 SpHb monitored) in a prospective, randomized, controlled trial to assess the impact of SpHb monitoring upon transfusions in patients undergoing elective orthopaedic surgery during a six month period. The results are a drop of 86% in transfusions as shown in Table 2. This amazing drop compared to the Awada study may be due to the lower prevalence of blood transfusion among this type of patients: Table 2. Blood transfusions in Ehrenfeld study [11] Standard Care Group Patients Transfused (N) 7 1 Transfused (N) 4.5% 0.6% SpHb Group 5.3. Transfusion Costs Health costs vary widely worldwide. Depending on the country, transfusion costs (linked to an increase in mortality and morbidity) can vary. Data from four systematic studies [12-15] estimated the cost per unit of transfused RBCs from $332 to $717 in To accurately determine the cost of blood in a surgical population from a health system perspective, an activitybased costing (ABC) model was constructed in a study [16] where Tasks and resource consumption (materials, labour, third-party services and capital) related to blood administration were identified prospectively at two US and two European hospitals. The new methodology showed that the real cost of blood transfusions was in the range of $522 and $1,183 (mean, $761 ± $294). This study presented the cost of transfusions in two US hospitals and two European hospitals (Austria and Switzerland). In Spain, a study made in 2007 [17] showed that the cost of a transfusion for the health care system was 350. Overall, adverse events from transfusions, for example in the US, account for about $17 Billion, and in effect add more to the cost of each transfusion than acquisition and procedure costs combined [18]. When mentioning Hospital units or departments, SpHb real-time monitoring could contribute to $93,600 in net annual cost savings in a typical surgical department and $67,350 in an intensive care department [19]. 6. Conclusions In this study there have been analysed five different studies showing accuracy and correlation while two of them showed also blood transfusion savings and effectiveness when Masimo Radical-7 Pulse Co-oxymeter and the SpHb sensor is used in comparison with the invasive, traditional measurement procedures. In terms of economic savings associated to the blood transfusion procedure, eight studies where analysed. Healthcare institutions are under increasing pressure to improve the quality and safety of patient care while improving efficiencies and decreasing costs. Therefore, a decrease in health cost, while improving patient safety, is expected when using this new measurement methodology. References [1] Taylor, RW. et al. Crit Care Med. 2006;34 (9): [2] Bernard, AC. et al. Journal of the American College of Surgeons. 2009;208: [3] Surgeons SD et al, for the Northern New England Cardiovascular Disease Study Group. Anesthesia & Analgesia 2009;108: [4] Awada W.F.N.; Maher F. Reduction in Red Blood Cell Transfusions during Neurosurgery with Noninvasive and Continuous Hemoglobin Monitoring. Proceeding of the Society for Technology in Anesthesia Annual Meeting, 2013: p 51. [5] Masimo Corporation.

7 166 B. Ribed-Sanchez et al. / Procedia Engineering 132 ( 2015 ) [6] Masimo FDA 510(k) Submission Data using normal sensitivity mode. [7] Frasca, D.; Dahyot-Fizelier, C.; Catherine, K.; Levrat, Q.; Debaene, B.; Mimoz, O. (2011). Accuracy of a continuous noninvasive hemoglobin monitor in intensive care unit patients. Critical Care Medicine 39 (10): [8] Gehring H, et al. Anesth Anag 2007;105:S Masimo FDA Submission Data. 2 [9] Berkow, L.; Rotolo, S.; and Mirski, E. Continuous noninvasive hemoglobin monitoring during complex spine surgery, Anesthesia and Analgesia, vol. 113, no. 6, pp , [10] Lamhaut, L.; Apriotesei, R.; Combes, X.; Lejay, M.; Carli, P.; and Vivien, B. Comparison of the accuracy of noninvasive hemoglobin monitoring by spectrophotometry (SpHb) and hemocue with automated laboratory hemoglobin measurement, Anesthesiology, vol. 115, no. 3, pp , [11] Ehrenfeld, JM.; Henneman, JP.; Sandberg, WS. Impact of Continuous and Noninvasive Hemoglobin Monitoring on Intraoperative Blood Transfusions. American Society of Anesthesiologists. 2010;LB05. [12] Forbes, JM.; Anderson, MD.; Anderson, GF.; Bleecker, GC.; Rossi, EC.; Moss, GS. Blood transfusion costs: a multicentre study. Transfusion 1991;31: [13] Cantor, SB.; Hudson, DV.; Lichtiger, B.; Rubenstein, EB. Costs of blood transfusion: a process-flow analysis. J Clin Oncol 1998;16: [14] Etchason, J.; Petz, L.; Keeler, E.; Calhoun, L.; Kleinman, S.; Snider, C.; Fink, A.; Brook, R. The cost effectiveness of preoperative autologous blood donations. N Engl J Med 1995;332: [15] Cremieux, PY.; Barrett, B.; Anderson, K.; Slavin, MB. Cost of outpatient blood transfusion in cancer patients. J Clin Oncol 2000;18: [16] Shander, A.; Hofmann, A.; Ozawa, S.; Theusinger, O.M.; Gombotz, H.; Donat R. Activity-based costs of blood transfusions in surgical patients at four hospitals. Spahn from the Society for the Advancement of Blood Management (SABM) and the Medical Society for Blood Management (MSBM). American Society of Hematology Meeting, San Francisco, CA, December [17] Darbà, J.; Restovic, G.; Arocho, R. Coste de las trasfusiones sanguíneas en España. Revisión de la literatura Pharmacoeconomics-Spanish Research Articles 6 (2): [18] Shander, A.; Hofmann, A.; Gombotz, H.; Theusinger, OM.; Spahn, DR. "Estimating the cost of blood: Past, present, and future directions". Best practice & research. Clinical anaesthesiology. (2007). [19] Capgemini Report, 2009: Using Noninvasive Pulse CO-Oximetry to Help Improve Patient Safety, Reduce Costs and Increase Hospital Revenues.

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