Corresponding author at: Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (Incor – HCFMUSP), São Paulo, SP, Brazil.
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class="elsevierStyleSimplePara elsevierViewall">Postoperative management of anemia.</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Bruno Deltreggia Benites, Mariana Munari Magnus, Lorena Costa, Denise Menezes Brunetta, Roseny dos Reis Rodriges, Susankerle de Oliveira Costa Alves, Gil Cunha De Santis, Silvia Renata Cornélio Parolin Rizzo, Guilherme Rabello, Dante Mario Langhi Junior" "autores" => array:10 [ 0 => array:2 [ "nombre" => "Bruno Deltreggia" "apellidos" => "Benites" ] 1 => array:2 [ "nombre" => "Mariana Munari" "apellidos" => "Magnus" ] 2 => array:2 [ "nombre" => "Lorena" "apellidos" => "Costa" ] 3 => array:2 [ "nombre" => "Denise Menezes" "apellidos" => "Brunetta" ] 4 => array:2 [ "nombre" => "Roseny dos Reis" "apellidos" => "Rodriges" ] 5 => array:2 [ "nombre" => "Susankerle de Oliveira Costa" "apellidos" => "Alves" ] 6 => array:2 [ "nombre" => "Gil Cunha" "apellidos" => "De Santis" ] 7 => array:2 [ "nombre" => "Silvia Renata Cornélio Parolin" "apellidos" => "Rizzo" ] 8 => array:2 [ "nombre" => "Guilherme" "apellidos" => "Rabello" ] 9 => array:2 [ "nombre" => "Dante Mario Langhi" "apellidos" => "Junior" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2531137924000579?idApp=UINPBA00005G" "url" => "/25311379/00000046000000S1/v2_202405080720/S2531137924000579/v2_202405080720/en/main.assets" ] "en" => array:19 [ "idiomaDefecto" => true "cabecera" => "<span class="elsevierStyleTextfn">Special article</span>" "titulo" => "Consensus of the Brazilian association of hematology, hemotherapy and cellular therapy on patient blood management" "subtitulo" => "Anemia tolerance mechanisms" "tieneTextoCompleto" => true "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "S77" "paginaFinal" => "S82" ] ] "autores" => array:1 [ 0 => array:4 [ "autoresLista" => "Roseny dos Reis Rodrigues, Denise Menezes Brunetta, Lorena Costa, Bruno Deltreggia Benites, Mariana Munari Magnus, Susankerle de Oliveira Costa Alves, Gil Cunha De Santis, Silvia Renata Cornélio Parolin Rizzo, Guilherme Rabello, Dante Mario Langhi Junior" "autores" => array:10 [ 0 => array:3 [ "nombre" => "Roseny dos Reis" "apellidos" => "Rodrigues" "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0001" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0002" ] ] ] 1 => array:3 [ "nombre" => "Denise Menezes" "apellidos" => "Brunetta" "referencia" => array:3 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">c</span>" "identificador" => "aff0003" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">d</span>" "identificador" => "aff0004" ] 2 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">e</span>" "identificador" => "aff0005" ] ] ] 2 => array:3 [ "nombre" => "Lorena" "apellidos" => "Costa" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">f</span>" "identificador" => "aff0006" ] ] ] 3 => array:3 [ "nombre" => "Bruno Deltreggia" "apellidos" => "Benites" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">g</span>" "identificador" => "aff0007" ] ] ] 4 => array:3 [ "nombre" => "Mariana Munari" "apellidos" => "Magnus" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">g</span>" "identificador" => "aff0007" ] ] ] 5 => array:3 [ "nombre" => "Susankerle de Oliveira Costa" "apellidos" => "Alves" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">h</span>" "identificador" => "aff0008" ] ] ] 6 => array:3 [ "nombre" => "Gil Cunha" "apellidos" => "De Santis" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">i</span>" "identificador" => "aff0009" ] ] ] 7 => array:3 [ "nombre" => "Silvia Renata Cornélio Parolin" "apellidos" => "Rizzo" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">j</span>" "identificador" => "aff0010" ] ] ] 8 => array:4 [ "nombre" => "Guilherme" "apellidos" => "Rabello" "email" => array:1 [ 0 => "grabello.inovaincor@fz.org.br" ] "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">k</span>" "identificador" => "aff0011" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">*</span>" "identificador" => "cor0001" ] ] ] 9 => array:3 [ "nombre" => "Dante Mario Langhi" "apellidos" => "Junior" "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">l</span>" "identificador" => "aff0012" ] ] ] ] "afiliaciones" => array:12 [ 0 => array:3 [ "entidad" => "Hospital Israelita Albert Einstein são Paulo, São Paulo, SP, Brazil" "etiqueta" => "a" "identificador" => "aff0001" ] 1 => array:3 [ "entidad" => "Faculdade de Medicina da Universidade de São Paulo (FM USP), São Paulo, SP, Brazil" "etiqueta" => "b" "identificador" => "aff0002" ] 2 => array:3 [ "entidad" => "Centro de Hematologia e Hemoterapia do Ceará (HEMOCE), Fortaleza, CE, Brazil" "etiqueta" => "c" "identificador" => "aff0003" ] 3 => array:3 [ "entidad" => "Complexo Hospitalar da Universidade Federal do Ceará (EBSERH – UFC), Fortaleza, CE, Brazil" "etiqueta" => "d" "identificador" => "aff0004" ] 4 => array:3 [ "entidad" => "Faculdade de Medicina da Universidade Federal do Ceará (FM UFC), Fortaleza, CE, Brazil" "etiqueta" => "e" "identificador" => "aff0005" ] 5 => array:3 [ "entidad" => "Universidade de Pernambuco (UPE), Recife, PE, Brazil" "etiqueta" => "f" "identificador" => "aff0006" ] 6 => array:3 [ "entidad" => "Centro de Hematologia e Hemoterapia da Universidade Estadual de Campinas (Hemocentro UNICAMP), Campinas, SP, Brazil" "etiqueta" => "g" "identificador" => "aff0007" ] 7 => array:3 [ "entidad" => "Chamberlain University, Chicago, IL, USA" "etiqueta" => "h" "identificador" => "aff0008" ] 8 => array:3 [ "entidad" => "Hemocentro de Ribeirão Preto, Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP), Ribeirão Preto, SP, Brazil" "etiqueta" => "i" "identificador" => "aff0009" ] 9 => array:3 [ "entidad" => "Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular (ABHH), São Paulo, SP, Brazil" "etiqueta" => "j" "identificador" => "aff0010" ] 10 => array:3 [ "entidad" => "Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (Incor – HCFMUSP), São Paulo, SP, Brazil" "etiqueta" => "k" "identificador" => "aff0011" ] 11 => array:3 [ "entidad" => "Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM UNIFESP), São Paulo, SP, Brazil" "etiqueta" => "l" "identificador" => "aff0012" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0001" "etiqueta" => "⁎" "correspondencia" => "Corresponding author at: Instituto do Coração do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (Incor – HCFMUSP), São Paulo, SP, Brazil." ] ] ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:8 [ "identificador" => "fig0001" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1591 "Ancho" => 3083 "Tamanyo" => 363943 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "alt0001" "detalle" => "Figure " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spara001" class="elsevierStyleSimplePara elsevierViewall">Relationship between oxygen delivery and demand.</p>" ] ] ] "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0001" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="cesectitle0003">Introduction</span><p id="para0001" class="elsevierStylePara elsevierViewall">Understanding the physiological concepts of oxygen delivery (DO<span class="elsevierStyleInf">2</span>) is fundamental to understanding the variables that are capable of increasing, reducing or maintaining the supply of oxygen (O<span class="elsevierStyleInf">2</span>) to the body. Based on this reasoning, this text discusses the possible mechanisms for maintaining DO<span class="elsevierStyleInf">2</span> even with reduced hemoglobin levels.</p><p id="para0002" class="elsevierStylePara elsevierViewall">Adequate O<span class="elsevierStyleInf">2</span> supply guarantees tissue homeostasis within a physiological pattern of dynamic balance (<a class="elsevierStyleCrossRef" href="#fig0001">Figure 1</a>). This balance is guaranteed through adequate DO<span class="elsevierStyleInf">2</span> and nutrients and the removal of carbon dioxide, free radicals and other metabolic products. With a multifactorial cause, the imbalance between supply and demand can lead to harmful consequences for the body, such as accumulation of acidic metabolic products and, consequently, metabolic acidosis, cellular dysoxia, multiple organic dysfunctions, prolonged hospitalization and even death.<a class="elsevierStyleCrossRef" href="#bib0001"><span class="elsevierStyleSup">1</span></a><span class="elsevierStyleSup">,</span><a class="elsevierStyleCrossRef" href="#bib0002"><span class="elsevierStyleSup">2</span></a></p><elsevierMultimedia ident="fig0001"></elsevierMultimedia><p id="para0003" class="elsevierStylePara elsevierViewall">As can be seen from <a class="elsevierStyleCrossRef" href="#fig0001">Figure 1</a>, O<span class="elsevierStyleInf">2</span> distribution is a product of blood flow and arterial O<span class="elsevierStyleInf">2</span> content. When the DO<span class="elsevierStyleInf">2</span> decreases below a critical point, O<span class="elsevierStyleInf">2</span> consumption is impaired, leading to anaerobic metabolism and lactic acidosis.</p><p id="para0004" class="elsevierStylePara elsevierViewall">It is well known that prolonged cellular dysoxia, both in the surgical and intensive care environments, is associated with increased mortality. One of the vital goals of healthcare professionals is ensuring the adequacy of DO<span class="elsevierStyleInf">2</span> in critically ill patients, whether in the operating room or in the intensive care unit (ICU).</p><p id="para0005" class="elsevierStylePara elsevierViewall">To better understand the mechanisms of anemia tolerance, it is important to remember the DO<span class="elsevierStyleInf">2</span> variables and their physiological interactions.</p><span id="sec0002" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="cesectitle0004">Physiological aspects of oxygen delivery</span><p id="para0006" class="elsevierStylePara elsevierViewall">DO<span class="elsevierStyleInf">2</span> is a consequent product of arterial O<span class="elsevierStyleInf">2</span> content and cardiac output (CO). Therefore, it is necessary to understand all related variables with their deficits and treatment potential to optimize DO<span class="elsevierStyleInf">2</span>. DO<span class="elsevierStyleInf">2</span> is calculated by Formula 1.</p><p id="para9001" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleEnunciation" id="enun0001"><span class="elsevierStyleLabel">Formula 1</span><p id="para0007" class="elsevierStylePara elsevierViewall">Oxygen delivery<elsevierMultimedia ident="ueqn0001"></elsevierMultimedia></p></span></p><p id="para0008" class="elsevierStylePara elsevierViewall">DO<span class="elsevierStyleInf">2</span> = oxygen delivery; CaO<span class="elsevierStyleInf">2</span> = arterial oxygen content; CO = cardiac output</p><p id="para0009" class="elsevierStylePara elsevierViewall">The arterial oxygen content (CaO<span class="elsevierStyleInf">2</span> - Formula 2 below) is guaranteed, for the most part, by the amount of O<span class="elsevierStyleInf">2</span> transported bound to hemoglobin and, to a lesser extent, by the amount of O<span class="elsevierStyleInf">2</span> transported dissolved in the plasma. It is known that the solubility coefficient of O<span class="elsevierStyleInf">2</span> in plasma is low and, therefore, a small quantity of O<span class="elsevierStyleInf">2</span> is transported. Therefore, increases in DO<span class="elsevierStyleInf">2</span> are not possible through this means of transport under normal temperature and pressure conditions. On the other hand, we are aware that a hemoglobin molecule carries up to 1.37 mL of O<span class="elsevierStyleInf">2</span>, that is, the DO<span class="elsevierStyleInf">2</span> can be increased by improving the hemoglobin level. However, it is known that very high hemoglobin levels are associated with worse viscosity and thus worse blood flow and that poorly indicated transfusions, for this reason alone, can worsen patients' clinical outcomes. It is also important to highlight that as the carrying capacity of hemoglobin is also finite (1.37 mL x Hb), this means that we cannot achieve a “scaled and proportional” improvement in DO<span class="elsevierStyleInf">2</span> through an isolated increase in the fraction of inspired O<span class="elsevierStyleInf">2</span> (FiO<span class="elsevierStyleInf">2</span>).</p><p id="para9002" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleEnunciation" id="enun0002"><span class="elsevierStyleLabel">Formula 2</span><p id="para0010" class="elsevierStylePara elsevierViewall">Arterial oxygen content<elsevierMultimedia ident="ueqn0002"></elsevierMultimedia></p></span></p><p id="para0011" class="elsevierStylePara elsevierViewall">CaO<span class="elsevierStyleInf">2</span> = arterial oxygen content; Hb = hemoglobin in grams per 100 mL of blood (14 to 15 g/dL); SaO<span class="elsevierStyleInf">2</span> =% oxyhemoglobin - fractional saturation of hemoglobin; 1.37 = number of milliliters of O<span class="elsevierStyleInf">2</span> linked to 1 g of saturated Hb; 0.003 = O<span class="elsevierStyleInf">2</span> solubility in plasma, vol% mmHg refers to the arterial blood sample; PaO<span class="elsevierStyleInf">2</span>: Partial pressure of oxygen</p><p id="para0012" class="elsevierStylePara elsevierViewall">Hypoxemia is defined as a reduction in arterial O<span class="elsevierStyleInf">2</span> content, while cellular dysoxia is defined as a metabolic imbalance, either due to a lack of O<span class="elsevierStyleInf">2</span> or due to an inadequate flow, which creates an imbalance between the generation and removal of toxic radicals resulting from cellular metabolism. Therefore, reductions in DO<span class="elsevierStyleInf">2</span> can lead to tissue dysoxia. An imbalance between delivery and demand leads to increased production or accumulation of markers resulting from anaerobic metabolism such as lactate, which can be measured in the laboratory.</p><p id="para0013" class="elsevierStylePara elsevierViewall">Another important point to understand DO<span class="elsevierStyleInf">2</span> is CO (Formula 3), where CO is the product of stroke volume and HR.</p><p id="para9003" class="elsevierStylePara elsevierViewall"><span class="elsevierStyleEnunciation" id="enun0003"><span class="elsevierStyleLabel">Formula 3</span><p id="para0014" class="elsevierStylePara elsevierViewall">Cardiac output<elsevierMultimedia ident="ueqn0003"></elsevierMultimedia></p></span></p><p id="para0015" class="elsevierStylePara elsevierViewall">DC= cardiac output; SV= stroke volume; HR= heart rate</p><p id="para0016" class="elsevierStylePara elsevierViewall">When analyzing CO variables, we know that the systolic volume will have its performance subordinated to the physiological properties of the myocardium such as preload, afterload and contractility, that is, changes in volume, in systemic vascular resistance and in contractility can lead to changes (for more or for less) in the CO and, consequently, impact DO<span class="elsevierStyleInf">2</span>. Patients with very high systemic vascular resistance may experience worsening of myocardial function due to increased cardiac work and a consequent drop in DO<span class="elsevierStyleInf">2</span>. On the other hand, dramatic drops in systemic vascular resistance can also generate tissue perfusion pressures so low that blood flow becomes unsatisfactory to meet the patient's tissue metabolic demand.<a class="elsevierStyleCrossRef" href="#bib0003"><span class="elsevierStyleSup">3</span></a></p><p id="para0017" class="elsevierStylePara elsevierViewall">Patients with impaired myocardial performance, such as those with severe heart failure or in cardiogenic shock, may not have sufficient stroke volume to guarantee tissue demand. This situation can also generate a drop in DO<span class="elsevierStyleInf">2</span>, an increase in lactate, an accumulation of metabolic waste (metabolic acidosis and renal failure) and a ‘slower’ venous return which can be observed in the laboratory with an increase in delta CO<span class="elsevierStyleInf">2</span> (difference in CO<span class="elsevierStyleInf">2</span> between arterial and venous blood gases of >6 mmHg) and a drop in central venous saturation (less than 65–70%).</p><p id="para0018" class="elsevierStylePara elsevierViewall">It is always very important, however, to individualize the conduct for each patient, closely observing their responses to interventions and their evolution. It is not true that every heart patient needs high hemoglobin values to improve their DO<span class="elsevierStyleInf">2</span>. In a systematic review that included patients submitted to cardiac surgery, it was concluded that a restrictive transfusion strategy of 7–8 g/dL is safe and reduced the use of red blood cell transfusions by 24%. The review also emphasizes that more research is necessary to define the ideal transfusion threshold in patients with acute myocardial infarction.<a class="elsevierStyleCrossRef" href="#bib0004"><span class="elsevierStyleSup">4</span></a></p><p id="para0019" class="elsevierStylePara elsevierViewall">Changes in HR tend to impact DO<span class="elsevierStyleInf">2</span> at its extremes. Very high frequencies that are not compatible with age (e.g., tachyarrhythmias) can impair systolic filling and coronary flow and, consequently, reduce CO and DO<span class="elsevierStyleInf">2</span>. However, extremely low HRs (symptomatic bradycardias) can also impair CO and there is also a drop in coronary flow.<a class="elsevierStyleCrossRef" href="#bib0003"><span class="elsevierStyleSup">3</span></a><span class="elsevierStyleSup">,</span><a class="elsevierStyleCrossRef" href="#bib0005"><span class="elsevierStyleSup">5</span></a></p><p id="para0020" class="elsevierStylePara elsevierViewall">Our organic systems interact to seek homeostasis and balance so that, even in cases of extreme anemia or a drop in stroke volume (e.g. hemorrhagic shock, extensive acute myocardial infarction), CO will try to compensate and maintain DO<span class="elsevierStyleInf">2</span> typically by increasing the HR. On the other hand, a significant reduction in HR or exaggerated pathological increases (tachyarrhythmias) will generate a state of tissue hypoperfusion and activation of sympathomimetic receptors. This activation of receptors leads to a reflex increase in systemic vascular resistance (SVR), in the body's compensatory attempt to maintain tissue perfusion pressure and guarantee DO<span class="elsevierStyleInf">2</span>, and coronary and cerebral perfusion. It is known, however, that this persistent increase in SVR can result in impaired organic perfusion and lead to cellular dysoxia if the cause of the imbalance is not resolved.</p><p id="para0021" class="elsevierStylePara elsevierViewall">It is extremely important to remember that all of these compensatory mechanisms have synergistic and temporary effects and that if the underlying cause of the ‘disorder’ is not resolved, the patient may progress to refractory shock and death.</p><p id="para0022" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#tbl0001">Table 1</a> illustrates the main clinical situations related to the variables affected by poor DO<span class="elsevierStyleInf">2</span> and the necessary interventions.</p><elsevierMultimedia ident="tbl0001"></elsevierMultimedia></span><span id="sec0003" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="cesectitle0005">Laboratory markers of cellular dysoxia</span><p id="para0024" class="elsevierStylePara elsevierViewall">Laboratory markers and diagnostic devices can be used to monitor tissue perfusion. However, in the clinical practice, many of these devices are expensive and are not readily available in healthcare units. In most services, there is arterial and venous blood gas analysis for decision making. With blood gases, indirect signs of anaerobic metabolism are observed as likely reasons for the drop in DO<span class="elsevierStyleInf">2</span>. It is very important to correlate clinical data with laboratory findings always. Therefore, the presence of metabolic acidosis may be a frequent finding in initial cases of shock. The progressive drop in bicarbonate, as well as more negative base excess (BE) values, should make the healthcare professional pay attention to a likely progressive to hypoperfusion even if the blood pressure is maintained.</p><p id="para0025" class="elsevierStylePara elsevierViewall">Lactate is the result of anaerobic metabolism and its progressive increase should serve as a warning about a metabolic deviation that is taking place; measures must be initiated to begin its ‘clearance’. Its rise to critical levels is associated with increased mortality especially in septic patients and trauma victims. Delta CO<span class="elsevierStyleInf">2</span> is the difference in CO<span class="elsevierStyleInf">2</span> between venous and arterial blood gases. When this difference is wide (>6 mmHg), this indicates tissue low blood flow.</p><p id="para0026" class="elsevierStylePara elsevierViewall">The reduced blood flow through tissues (e.g. cardiogenic shock) in cases of anemia can also lead to a drop in central venous saturation (SvO<span class="elsevierStyleInf">2</span>). Therefore, it can also be an indirect indicator of tissue hypoperfusion.</p><p id="para0027" class="elsevierStylePara elsevierViewall">Although several factors affect the SvO<span class="elsevierStyleInf">2</span> causing overestimations even with a concomitant drop in DO<span class="elsevierStyleInf">2</span> (e.g.: hypothermia, sepsis, hyperdynamic patients), low values tend to be more valued when analyzed within the patient's clinical context.</p><p id="para0028" class="elsevierStylePara elsevierViewall">Non-invasive or minimally invasive technologies can provide relevant information about tissue O<span class="elsevierStyleInf">2</span> before and after red blood cell transfusions. The application of oximetry techniques, such as electronic paramagnetic resonance (EPR-imaging), near infrared spectroscopy (NIRS), photoacoustic tomography (PAT) and blood oxygen level dependent magnetic resonance (BOLD-MRI), are interesting opportunities to measure O<span class="elsevierStyleInf">2</span> concentration (EPR) and saturation (NIRS, PAT and BOLD-MRI - <a class="elsevierStyleCrossRef" href="#tbl0002">Table 2</a>).<a class="elsevierStyleCrossRef" href="#bib0006"><span class="elsevierStyleSup">6</span></a> Unfortunately, due to their high cost, they are not yet widely available.</p><elsevierMultimedia ident="tbl0002"></elsevierMultimedia></span></span><span id="sec0004" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="cesectitle0006">Anemia tolerance mechanisms</span><p id="para0031" class="elsevierStylePara elsevierViewall">In view of what was previously discussed, it is more understandable that the mechanisms of tolerance to anemia depend directly on DO<span class="elsevierStyleInf">2</span> variables. Thus, strategies that reduce myocardial consumption, which range from analgesia to HR control, are applicable in different scenarios in the clinical practice.</p><p id="para0032" class="elsevierStylePara elsevierViewall">Another important point that we must remember is that patients should not be transfused considering fixed parameters, but rather based on metabolic needs.<a class="elsevierStyleCrossRef" href="#bib0007"><span class="elsevierStyleSup">7</span></a><span class="elsevierStyleSup">,</span><a class="elsevierStyleCrossRef" href="#bib0008"><span class="elsevierStyleSup">8</span></a> Monitoring macro hemodynamics and, more notably, micro hemodynamics is extremely important in making a rational decision. A clear example that we can highlight is neurocritical patients, victims of trauma, in which the ideal hemoglobin is not yet a well-established consensus. Although responsible for delivering O<span class="elsevierStyleInf">2</span>, it is also known that increases in hemoglobin can lead to increased viscosity with worse regional microcirculatory in some clinical situations.<a class="elsevierStyleCrossRef" href="#bib0009"><span class="elsevierStyleSup">9</span></a> Given this, increasingly new ways to monitor and individualize patients are being considering in an attempt to meet their real needs and rationalize transfusion indications.</p><p id="para9004" class="elsevierStylePara elsevierViewall"><elsevierMultimedia ident="tbox0002"></elsevierMultimedia></p></span><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="cesectitle0008">Conclusion</span><p id="para0037" class="elsevierStylePara elsevierViewall">The main objective of the clinical indication for red blood cell transfusion is to restore or maintain adequate oxygenation. Oxygen transport after transfusion is affected by numerous factors such as perfusion, allosteric saturation/desaturation of hemoglobin and tissue oxygen concentration.</p><p id="para0038" class="elsevierStylePara elsevierViewall">Bioavailable oxygen maintains tissue homeostasis. Homeostasis imbalance can be measured indirectly by tissue and technological markers at the bedside. The ‘active search’ for this imbalance in critically ill patients can be valuable to assess the quality of oxygen delivery, the real need for transfusions and, thus, guide appropriate action.</p></span></span>" "textoCompletoSecciones" => array:1 [ "secciones" => array:6 [ 0 => array:3 [ "identificador" => "xres2141602" "titulo" => "Abstract" "secciones" => array:1 [ 0 => array:1 [ "identificador" => "abss0001" ] ] ] 1 => array:2 [ "identificador" => "xpalclavsec1818161" "titulo" => "Keywords" ] 2 => array:3 [ "identificador" => "sec0001" "titulo" => "Introduction" "secciones" => array:2 [ 0 => array:2 [ "identificador" => "sec0002" "titulo" => "Physiological aspects of oxygen delivery" ] 1 => array:2 [ "identificador" => "sec0003" "titulo" => "Laboratory markers of cellular dysoxia" ] ] ] 3 => array:2 [ "identificador" => "sec0004" "titulo" => "Anemia tolerance mechanisms" ] 4 => array:2 [ "identificador" => "sec0005" "titulo" => "Conclusion" ] 5 => array:1 [ "titulo" => "References" ] ] ] "pdfFichero" => "main.pdf" "tienePdf" => true "fechaRecibido" => "2024-02-09" "fechaAceptado" => "2024-02-18" "PalabrasClave" => array:1 [ "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec1818161" "palabras" => array:5 [ 0 => "Metabolic acidosis" 1 => "Cellular dysoxia" 2 => "Cardiac output" 3 => "Arterial and venous blood gas analysis" 4 => "Oxygen delivery (DO<span class="elsevierStyleInf">2</span>)" ] ] ] ] "tieneResumen" => true "resumen" => array:1 [ "en" => array:2 [ "titulo" => "Abstract" "resumen" => "<span id="abss0001" class="elsevierStyleSection elsevierViewall"><p id="spara007" class="elsevierStyleSimplePara elsevierViewall">Understanding the physiological concepts of oxygen delivery is essential to discern the mechanisms that influence its increase, reduction or maintenance in the body. This text explores the different mechanisms that help maintain oxygen delivery even in the face of reduced hemoglobin levels. Adequate oxygen delivery ensures tissue and metabolic balance, which is crucial to avoid harmful consequences such as metabolic acidosis and cellular dysoxia. The complex interaction between variables such as cardiac output, hemoglobin and heart rate (HR) plays a fundamental role in maintaining oxygen delivery, allowing the body to temporarily adjust to situations of anemia or high metabolic demand. It is important to emphasize that blood transfusions should not be based on fixed values, but rather on individual metabolic needs. Strategies to reduce myocardial consumption and monitor macro and micro hemodynamics help in making rational decisions. Individualizing treatment and considering factors such as blood viscosity in relation to the benefits of transfusion are increasingly relevant to optimize therapy and minimize risks, especially in complex clinical scenarios, such as neurocritical patients and trauma victims.</p></span>" ] ] "multimedia" => array:7 [ 0 => array:8 [ "identificador" => "fig0001" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1591 "Ancho" => 3083 "Tamanyo" => 363943 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "alt0001" "detalle" => "Figure " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spara001" class="elsevierStyleSimplePara elsevierViewall">Relationship between oxygen delivery and demand.</p>" ] ] 1 => array:8 [ "identificador" => "tbl0001" "etiqueta" => "Table 1" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "detalles" => array:1 [ 0 => array:3 [ "identificador" => "alt0002" "detalle" => "Table " "rol" => "short" ] ] "tabla" => array:2 [ "leyenda" => "<p id="spara003" class="elsevierStyleSimplePara elsevierViewall">CaO<span class="elsevierStyleInf">2</span>: Arterial oxygen content; Hb: Hemoglobin; SaO<span class="elsevierStyleInf">2</span>: Oxygen saturation; PaO2: Partial pressure of oxygen; CO: Cardiac output; SV: Stroke volume; HR: Heart rate; IAB: intra-aortic balloon; ECMO: extracorporeal membrane oxygenation.</p>" "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><a name="en0001"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">Situation \t\t\t\t\t\t\n \t\t\t\t\t\t</th><a name="en0002"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">CaO<span class="elsevierStyleInf">2</span>1.37 x Hb x SaO<span class="elsevierStyleInf">2</span> x PaO<span class="elsevierStyleInf">2</span> \t\t\t\t\t\t\n \t\t\t\t\t\t</th><a name="en0003"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">COCO = SV x HR \t\t\t\t\t\t\n \t\t\t\t\t\t</th><a name="en0004"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">Desired intervention \t\t\t\t\t\t\n \t\t\t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><a name="en0005"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Anemia (dependent on the hemoglobin level and each patient`s comorbidities \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0006"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Drop in CaO<span class="elsevierStyleInf">2</span> \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0007"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Can compensate with increase in HR \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0008"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Improve the supply/Hb production (if possible): correction of the anemia (see the possibility of iron, erythropoietin, etc.) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0009"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Severe anemia (hemorrhagic shock) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0010"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Drop in CaO<span class="elsevierStyleInf">2</span> dependent on the hemoglobin level \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0011"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Can compensate with increase in HR, however hypotension and signs of bad clinical perfusion are evident (drop in diuresis, cold and clammy skin, alteration in awareness, etc.) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0012"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Consider concentrated red blood cell transfusions and/or volume replacement (escalation of therapy depends on the degree of shock - from I to IV) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0013"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Drop in oxygenation (e.g.: lack of intubation, hypoxemic respiratory failure) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0014"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Drop in CaO<span class="elsevierStyleInf">2</span> \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0015"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initial increase in HR as compensatory mechanism; if not resolved, drop in SV and CO – bradycardia and cardiorespiratory arrest \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0016"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Improve DO<span class="elsevierStyleInf">2</span> depending on underlying cause \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0017"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Tachyarrhythmia \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0018"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initially it is unaffected in well-oxygenated patients \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0019"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Pathologic increase in HR with impairment of diastolic filling – drop in SV and CO. Can evolve to cardiorespiratory arrest \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0020"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Treat the arrhythmia according to Advanced Cardiac Life Support guidelines of the American Heart Association \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0021"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Bradyarrhythmia \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0022"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initially it is unaffected in well-oxygenated patients \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0023"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Pathologic drop in HR (impairment of coronary perfusion) can lead to ischemia, drop in CO and even cardiorespiratory arrest \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0024"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Treat the arrhythmia according to Advanced Cardiac Life Support guidelines of the American Heart Association (drugs or pacemaker) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0025"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Cardiogenic shock \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0026"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initially it is unaffected in well-oxygenated patients \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0027"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Patient may present with impaired CO, SV or both \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0028"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Depending on the cause (inotropic agents, antiarrhythmics or invasive ventricular assist devices (such as IAB, ECMO) may be necessary \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0029"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Obstructive shock \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0030"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">CaO<span class="elsevierStyleInf">2</span> may drop depending on the cause (e.g.: massive pneumothorax or hemothorax) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0031"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Drop in CO due to reduced venous return or filling of the right ventricle (tamponade for example) and consequent drop in SV \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0032"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Make a correct diagnosis and intervene \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0033"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Distributive shock \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0034"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initially it is unaffected in well-oxygenated patients \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0035"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Vasoplegia may lead to a drop in arterial pressure with a reduction in venous return and SV; Although the CO may be hyperdynamic in some situations \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0036"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Make a correct diagnosis and intervene \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0037"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Hypothermia \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0038"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initially it is unaffected in well-oxygenated patients – in situations of deep hypothermia (a rare condition), the CaO<span class="elsevierStyleInf">2</span> may be augmented due to an increase in solubility of O<span class="elsevierStyleInf">2</span> in the liquid (plasma) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0039"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initially there is a compensatory increase in the CO to attempt to supply the organism and maintain homeostasis; if it persists the HR and CO drop \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0040"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Gradual rewarming \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0041"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Sedation/analgesia \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0042"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Initially it is unaffected in well-oxygenated patients.In sedated and badly oxygenated patients, it may lead to a drop in the CaO<span class="elsevierStyleInf">2</span> \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0043"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Well indicated, analgesics and sedation normally promote anxiolysis, with consequent reduction in HR, and improvement in diastolic filling, SV and CO. Excessive sedation or inappropriate use of sedative drugs can cause hypotension, a drop in SV and consequently a drop in CO \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0044"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Adequate analgesia and sedation for each nociceptive stimulation \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab3530396.png" ] ] ] ] "descripcion" => array:1 [ "en" => "<p id="spara002" class="elsevierStyleSimplePara elsevierViewall">Correlation between the main clinical situations and the variables affected by oxygen delivery.</p>" ] ] 2 => array:8 [ "identificador" => "tbl0002" "etiqueta" => "Table 2" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "detalles" => array:1 [ 0 => array:3 [ "identificador" => "alt0003" "detalle" => "Table " "rol" => "short" ] ] "tabla" => array:2 [ "leyenda" => "<p id="spara005" class="elsevierStyleSimplePara elsevierViewall">oxy-Hb: oxyhemoglobin; deoxy-Hb: Deoxygenated hemoglobin.</p><p id="spara006" class="elsevierStyleSimplePara elsevierViewall">Adapted from Bock and Buchler (2019).</p>" "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><a name="en0045"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">Technology \t\t\t\t\t\t\n \t\t\t\t\t\t</th><a name="en0046"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">Enhancement agents used \t\t\t\t\t\t\n \t\t\t\t\t\t</th><a name="en0047"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">What this technology measures \t\t\t\t\t\t\n \t\t\t\t\t\t</th><a name="en0048"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">Tissue thickness \t\t\t\t\t\t\n \t\t\t\t\t\t</th><a name="en0049"></a><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="" valign="top" scope="col" style="border-bottom: 2px solid black">Examples in transfusion (ref #) \t\t\t\t\t\t\n \t\t\t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><a name="en0050"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Near infrared spectroscopy (NIRS) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0051"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Endogen: Total Hb, oxy-Hb, deoxy-Hb \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0052"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">% oxygen saturation (%SO<span class="elsevierStyleInf">2</span>) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0053"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Soft tissue: 5–10 mmBrain: variable \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0054"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Clinical [38##, 39#, 40] \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0055"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Photoacoustic tomography (PAT) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0056"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Endogen: Total Hb, oxy-Hb, deoxy-Hb \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0057"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">% oxygen saturation (%SO<span class="elsevierStyleInf">2</span>), partial oxygen pressure (pO<span class="elsevierStyleInf">2</span> - mmHg) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0058"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Mathematical model dependent (1–12 mm) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0059"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">No available study \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0060"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Positron emission tomography \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0061"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Exogen: radiolabeled O<span class="elsevierStyleInf">2</span> (oxygen-15) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0062"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Distribution and metabolism of oxygen in tissue \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0063"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Total thickness of the tissue \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0064"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Clinical [58] \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0065"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Blood oxygen level dependent magnetic resonance (BOLD-MRI) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0066"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Endogen: deoxy-Hb with or without exogen (dimeglumine gadopentetate) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0067"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Partial oxygen pressure (pO<span class="elsevierStyleInf">2</span> - mmHg) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0068"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Depends on the resonators used: 1–10 mm for surface resonators and up to 80 mm for implantable resonators \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0069"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Pre-clinical [4#] \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0070"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Electronic paramagnetic resonance (EPR-imaging) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0071"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Exogen: composed of trityl base (Oxo63, TAM-H) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0072"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Partial oxygen pressure (pO2 mmHg)Tissue mapping \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0073"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">10–20 mm \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0074"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">No available study \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0075"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Phosphorescence quenching \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0076"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Exogen: Oxyphor R2 Oxyphor G4 \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0077"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Partial oxygen pressure (pO<span class="elsevierStyleInf">2</span> mmHg) \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0078"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Depends on the distribution of the quenching agent in the tissue \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0079"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Pre-clinical [59] \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><a name="en0080"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Hypoxyprobe™ \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0081"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Exogen: pimonidazole \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0082"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Nitroimidazole adducted proteins (occur at <10 mmHg pO<span class="elsevierStyleInf">2</span>) that can be detected by immunohistochemistry, Western blot and mass spectrometry \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0083"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Total thickness of the tissue \t\t\t\t\t\t\n \t\t\t\t</td><a name="en0084"></a><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="" valign="top">Pre-clinical [3#] \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab3530397.png" ] ] ] ] "descripcion" => array:1 [ "en" => "<p id="spara004" class="elsevierStyleSimplePara elsevierViewall">Technologies that measure tissue oxygen with potential use for transfusions.</p>" ] ] 3 => array:5 [ "identificador" => "ueqn0001" "tipo" => "MULTIMEDIAFORMULA" "mostrarFloat" => false "mostrarDisplay" => true "Formula" => array:5 [ "Matematica" => "DO2=CaO2×CO" "Fichero" => "STRIPIN_si1.jpeg" "Tamanyo" => 168 "Alto" => 12 "Ancho" => 106 ] ] 4 => array:5 [ "identificador" => "ueqn0002" "tipo" => "MULTIMEDIAFORMULA" "mostrarFloat" => false "mostrarDisplay" => true "Formula" => array:5 [ "Matematica" => "CaO2=1.37×Hb×SaO2+(0.003×PaO2)" "Fichero" => "STRIPIN_si2.jpeg" "Tamanyo" => 177 "Alto" => 13 "Ancho" => 253 ] ] 5 => array:5 [ "identificador" => "ueqn0003" "tipo" => "MULTIMEDIAFORMULA" "mostrarFloat" => false "mostrarDisplay" => true "Formula" => array:5 [ "Matematica" => "CO=SV×HR" "Fichero" => "STRIPIN_si3.jpeg" "Tamanyo" => 166 "Alto" => 10 "Ancho" => 86 ] ] 6 => array:7 [ "identificador" => "tbox0002" "tipo" => "MULTIMEDIATEXTO" "mostrarFloat" => false "mostrarDisplay" => true "detalles" => array:1 [ 0 => array:3 [ "identificador" => "alte1" "detalle" => "Unlabelled bo" "rol" => "short" ] ] "texto" => array:1 [ "textoCompleto" => "<span class="elsevierStyleSections"><p id="para0033" class="elsevierStylePara elsevierViewall"><ul class="elsevierStyleList" id="celist0001"><li class="elsevierStyleListItem" id="celistitem0001"><span class="elsevierStyleLabel">1.</span><p id="para0034" class="elsevierStylePara elsevierViewall">Directly or indirectly monitor whether oxygen delivery is adequate in critical patients.</p></li><li class="elsevierStyleListItem" id="celistitem0002"><span class="elsevierStyleLabel">2.</span><p id="para0035" class="elsevierStylePara elsevierViewall">Measures to improve metabolism should be a priority in patients with signs of hypoperfusion or clear signs of poor tissue perfusion.</p></li><li class="elsevierStyleListItem" id="celistitem0003"><span class="elsevierStyleLabel">3.</span><p id="para0036" class="elsevierStylePara elsevierViewall">Transfusion of packed red blood cells should not be based on pre-established numbers; it is recommended that decisions be individualized for each patient, taking into account their comorbidities, their current clinical status and tissue perfusion markers.</p></li></ul></p></span>" ] "descripcion" => array:1 [ "en" => "<p id="spara008" class="elsevierStyleSimplePara elsevierViewall">Recommendations</p>" ] ] ] "bibliografia" => array:2 [ "titulo" => "References" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "cebibsec1" "bibliografiaReferencia" => array:9 [ 0 => array:3 [ "identificador" => "bib0001" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Red blood cell transfusion and skeletal muscle tissue oxygenation in anaemic haematologic outpatients" "autores" => array:1 [ 0 => array:2 [ "etal" => true "autores" => 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