Key Points
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The shortage of organs available for transplantation is a worldwide problem.
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The discrepancy between the number of patients waiting for organ transplantation and the available organs remains significant, but has narrowed since 2013.
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Most organs in the United States are donated after neurologic death, with a small portion donated after circulatory death and from living organ donors.
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Neurologic-death donors have physiologic alterations that must be actively managed to ensure that the organs are suitable for transplantation.
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Determining neurologic death and circulatory death should follow national guidelines and local institutional protocols.
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The anesthesiologist must have an awareness of the ethical and legal issues related to the declaration of death that precedes organ donation.
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Expansion of the donor pool through the inclusion of extended criteria, such as high-risk donors, addresses the organ shortage and decreases waiting-list mortality.
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The use of extended criteria high-risk organs significantly impacts recipient outcomes and presents challenges to perioperative management.
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Ischemia-reperfusion injury in organ transplantation is unavoidable; however, management strategies can lessen the likelihood of postoperative graft failure.
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Goal-directed donor management can improve the number of organs transplanted per donor.
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Living organ donor kidney transplantation remains an important donor source in the United States, whereas the use of living donors for liver transplantation varies by country.
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New technologies, including machine perfusion after procurement, are promising as a means to mitigate the effects of prolonged preservation time, to increase the donor pool, and to improve transplant recipient outcomes.
Introduction
Organ transplantation requires the donation and successful procurement of a human organ. The success of organ transplantation relies on a functioning donor graft. The majority of organs used for transplantation in the United States are from donors after the declaration of neurologic death (donation after neurologic death, DND). Organs from donation after circulatory (cardiac) death (DCD) and living organ donation are in the minority, however, they remain an important source of donors. Organs procured from these sources have different characteristics and present varying challenges in management. For instance, DND donors often have significant physiologic alterations and hemodynamic instability that is associated with neurologic death. These alterations and instability, if not treated, will lead to organ deterioration and may prevent the organ from being suitable for transplantation. In contrast, DCD donors have an obligatory period of hypotension of varying duration before cardiac arrest. The resulting compromise in perfusion can exacerbate reperfusion injury and lead to an increased incidence of posttransplant biliary dysfunction.
The shortage of organs is a worldwide problem and is the most important obstacle in organ transplantation. The gap between the number of patients waiting for transplant and the available organs has widened ( Fig. 61.1 ). In 2015, more than 119,000 transplant candidates were wait-listed in the United States through the United Network for Organ Sharing. Of these, 33,000 candidates underwent transplant surgery. The majority of candidates were awaiting kidney grafts, with a smaller number awaiting liver, heart, and lung grafts. Many strategies were implemented to decrease the gap between the demand and supply, including public awareness campaigns and updates to the organ allocation system. Organ donation rates and the number of organs transplanted per donor vary substantially across geographic regions. Per 100 eligible deaths in the United States in 2016, the organ donation rate was 72.3, ranging from 52.9 to a high of 93.3 (Israni OPTN 2016 Annual Data Report). To increase the number of organs for transplant, many programs have expanded the donor pool by using extended criteria donors (ECDs). Not surprisingly, the number of organs transplanted per donor varies according to donor category: ECD, DCD, or standard criteria donor (SCD). The number of organs transplanted from DCD donors is similar to ECDs, primarily attributable to the ability of the kidney to tolerate the longer periods of ischemia associated with organ procurement after DCD. The use of living-related and living-unrelated donors is widespread in countries with moral or legal objections to neurologic death and is an important worldwide donor source. Many policies have been proposed to promote the best practices in organ donation. There are several areas that have the potential to expand the donor pool, which include deaths that are not referred to the organ sharing agencies and organs that have been procured, but unused for transplant.
Organ transplantation is a complex process that requires close coordination among many specialized teams. Procurement organizations, transplant coordinators, social workers, nurses, surgeons, internists, intensivists, and anesthesiologists are involved in the process. To maximize the number of organs transplanted and to preserve the best possible function of donated organs, anesthesiologists need to understand the pathophysiologic derangements associated with donation and ischemia-reperfusion injury. In addition, anesthesiologists must be aware of the ethical and legal issues related to the declaration of death and organ donation.
Management of Organ Donors After Declaration of Neurologic Death
DND (also called after declaration of brain death) provides the majority of donated organs in the United States. Organ procurement from DND donors can only occur after the declaration of death. The concept of neurologic death emerged in the 1950s. In 1968, a Harvard Ad Hoc Committee on Irreversible Coma established a set of criteria that has been widely used for the determination of neurologic death. In the United States, the Uniform Determination of Death Act was approved in 1981 by the National Conference of Commissioners on Uniform State Laws, in cooperation with the American Medical Association, the American Bar Association, and the President’s Commission for the Study of Ethical Problems in Medicine and Biomedical and Behavioral Research. Although the criteria for the declaration of neurologic death were based on ethical principles established several decades ago, the criteria remain valid today.
Although the concept of neurologic death has been widely accepted in Western cultures, minor variations in definition and implementation exist in different countries. Despite these differences, the clinical criteria are similar. A larger difference exists among different cultures in accepting and implementing the neurologic death criteria. In fact, neurologic death has not reached a legal status in some countries, such as China.
Pathophysiologic Changes With Neurologic Death
A variety of pathophysiologic changes are associated with neurologic death. The pathophysiologic mechanisms of neurologic death have profound effects at the molecular, cellular, and tissue levels. The clinical presentations associated with neurologic death may be complex and vary from patient to patient. They can be further complicated by prior pathologic abnormalities, disease, and therapy. The typical pathophysiologic changes associated with neurologic death are further described in Table 61.1 .
| Signs and Symptoms | Pathophysiologic Changes | Incidence (%) |
|---|---|---|
| Hypertension | Catecholamine storm | 80-90 |
| Hypotension | Vasoplegia, hypovolemia, reduced coronary blood flow, myocardial dysfunction | 80-90 |
| Bradycardia and other arrhythmias | Catecholamine storm, myocardial damage, reduced coronary blood flow | 25-30 |
| Pulmonary edema | Acute blood volume diversion, capillary damage | 10-20 |
| Diabetes insipidus | Posterior pituitary damage | 45-80 |
| Disseminated intravascular coagulation | Tissue factor release, coagulopathy | 30-55 |
| Hypothermia | Hypothalamic damage, reduced metabolic rate, vasodilation, and heat loss | Varied |
| Hyperglycemia | Decreased insulin concentration, increased insulin resistance | Common |
Cardiovascular Responses to Neurologic Death
The cardiovascular system is closely regulated by the central neural system. Cardiovascular responses to neurologic death usually consist of two phases. The first phase is characterized by sympathetic discharge (catecholamine storm), which causes intense vasoconstriction or elevated systemic vascular resistance (hypertensive crisis), tachycardia, and a redistribution of blood volume with visceral ischemia. Acute myocardial injury can occur in neurologic-dead donors without a history of coronary artery disease. Echocardiographic evidence of myocardial dysfunction is observed in 40% of neurologic-dead donors under consideration for heart donation. At times, parasympathetic activation can result in bradycardia. After the sympathetic discharge of the first phase, the loss of sympathetic tone, decreased cardiac output, blunted hemostatic responses, and severe peripheral vasodilatation (vasoplegia) characterize the second phase. In addition to neurohormonal disturbances, other contributing factors include blood loss, intravascular depletion attributable to capillary leakage, osmotic therapy for rising intracranial pressure (ICP), and diabetes insipidus.
The first phase is correlated with ischemia in various parts of the brain and is attributable to an increase of ICP, and the second phase is caused by cerebral herniation and spinal cord ischemia. Although the first hypertensive phase generally represents a transient period in the progression to neurologic death, the second hypotensive phase is profound and sustained. Failure to correct these cardiovascular derangements results in poor organ perfusion and inadequate tissue oxygenation, which will threaten the viability of the donated organs.
Respiratory Responses to Neurologic Death
An increase in systemic vascular resistance after neurologic death results in blood shifting from the systemic circulation to the more compliant pulmonary circulation. The resulting increase in hydrostatic pressure in the pulmonary circulation causes pulmonary capillary leakage and pulmonary edema. Sympathetic activity triggers a sterile systemic inflammatory response, initiating infiltration of neutrophils and increasing pulmonary endothelial permeability, which further contributes to lung injury. Proinflammatory cytokines are released at the alveoli and are associated with early graft failure and mortality after lung transplantation. The inflammatory response in neurologic-dead donors is associated with the deterioration in cardiac function and a shift to anaerobic metabolism. Hormonal instability can reduce alveolar fluid clearance, resulting in significant accumulation of extravascular lung water. If ventilation is not supported, then respiratory arrhythmia progresses to apnea and cardiac arrest.
Endocrine, Metabolic, and Stress Responses to Neurologic Death
Neurologic death is frequently associated with pituitary failure and disturbances of cortisol, thyroid hormones, antidiuretic hormone, and insulin. Posterior pituitary function in neurologic-dead donors is frequently lost. The development of central diabetes insipidus results in severe fluid and electrolyte derangements and can be observed in up to 90% of neurologic-dead donors. Anterior pituitary function in neurologic death can also be affected, resulting in a deficiency in triiodothyronine (T 3 ) and thyroxine (T 4 ), adrenocorticotropic hormone, thyroid-stimulating hormone, and human growth hormone. Thyroid hormonal deficiency may be similar to the euthyroid sick syndrome commonly observed in the non-neurologic injured patient with multisystem organ failure. Hyperglycemia is commonly encountered in neurologic-dead donors because of decreased insulin concentrations and increased insulin resistance. Hypothalamic function and control of body temperature are lost. Although hyperpyrexia may initially occur, hypothermia follows, which is caused by a reduction in metabolic rate and muscle activity, in combination with peripheral vasodilation. Disseminated intravascular coagulation is present in up to one-third of isolated patients with head injuries and is believed to be caused by the release of tissue thromboplastin from brain tissue.
Donation After Circulatory (Cardiac) Death
Before the acceptance of neurologic death, all organs procured were from donors who suffered a cardiac demise (DCD, previously known as donation from a non–heart-beating donor). After the establishment of the Harvard criteria for neurologic death, DND quickly became the principal source of organ donation. However, an interest in the use of DCD organs has been renewed in recent years, driven by the persistent shortage of DND donors and the lack of acceptance of neurologic death in some countries. Policies and protocols developed by healthcare organizations now encourage DCD organs, and their use is increasing in the United States and other countries. In the United States, the number of DCD donors continues to increase, and accounted for over 17% of donors in 2016 ( Fig. 61.2 ). During the same period, the number of living donors dropped slightly from 7000 to 6600. Kidney grafts accounted for over 95% of the organs transplanted from living donors during this period. The American Society of Anesthesiologists established a Sample Policy for Organ Donation after Circulatory Death, with the recommendation that its members actively participate in the development of institutional DCD protocols.
DCD donors are divided into five categories: I, patients who are dead on arrival at the hospital; II, unsuccessfully resuscitated patients; III, patients in whom cardiac arrest is imminent; IV, cardiac arrest in neurologic-dead donors; V, unexpected arrest in the intensive care unit (ICU). Categories III and IV are considered as controlled DCDs, whereas the remaining categories are considered uncontrolled DCDs. Controlled DCD implies that life-support withdrawal can be planned and the transplant team is awaiting the cardiac arrest and is ready for rapid organ recovery. In contrast, uncontrolled DCD implies the patient has experienced an unanticipated cardiac arrest, and organ donation is considered only after an unsuccessful resuscitation. Warm ischemia time is significantly longer in uncontrolled DCDs. Currently, most DCD donors for organ transplantation are controlled DCD donors. Successful use of the uncontrolled DCD grafts has been reported in several studies.
DCD donors usually suffer from irreversible brain or spinal injury but do not meet the neurologic death criteria. The prognosis for a meaningful quality of life is poor. Withdrawal of therapy must be based on a clinical decision of futility and conform to the wishes of the patient and family. The consideration of the withdrawal of life-sustaining therapies must be independent from any discussion related to transplantation. The transplantation team cannot be involved in this decision. Drugs can be used to relieve pain and anxiety and to provide comfort for the patient during withdrawal. Therapies designed to improve graft quality, but without benefit to the patient, are controversial; however, therapies with minimal impact on the patient that improve organ survival are allowed in some protocols.
Declaration of circulatory death should follow procedures proposed by national organizations and policies adopted by the local institution. After a decision has been made to withdraw support, the trachea is extubated and life support is stopped. A physician who is not involved with organ transplantation declares cessation of cardiac function. Declaration of circulatory death is not different from clinical practice, which requires a clinical examination to confirm pulselessness or the absence of an arterial waveform. The duration between cessation of cardiovascular activities and the declaration of circulatory death is usually 2 to 5 minutes to ensure irreversibility. Organ procurement starts after death is declared.
Although organs procured from DCD donors are not exposed to the physiologic derangements of neurologic death, they are at greater risk for ischemia-reperfusion injury than organs from DND donors. This results from hypoxemia and ischemia in a warm environment, which is unique during DCD procurement. The time elapsed from extubation to circulatory death is an important factor for determining the suitability of organ donation. If spontaneous breathing and/or heart function continues for a prolonged period after life support withdrawal, then the organs may not be suitable for transplantation, particularly in donors with comorbidities. To assist physicians in predicting how long a patient will sustain life after the withdrawal of life support, a 6-variable score was developed by the University of Wisconsin (UW) ( Table 61.2 ). A low score (8-12) means that breathing and/or cardiac function will continue for some time. A high score (19-24) means that apnea and cardiac arrest are imminent.
| Variables | Points |
|---|---|
| Spontaneous respiration after 10 min | |
|
|
| Body mass index (kg/m 2 ) | |
|
|
| Vasopressors | |
|
|
| Patient age (years) | |
|
|
| Intubation | |
|
|
| Oxygenation after 10 min | |
|
|
The two separate definitions and procedures used for DND and DCD have led to a new debate about the definition and determination of death. A uniform concept of death, which combines all previous criteria for death, is emerging. A growing consensus is that all criteria used to diagnose human death rely on the demonstration of the irreversible loss of the capacity to breath, combined with the irreversible loss of the capacity for consciousness. The irreversible loss of these two functions equates to human death.
Category III (impending cardiac arrest) DCD is the ideal source for organ transplant. Kidneys from DCD donors are frequently used. Several studies have shown that, despite a higher incidence of delayed graft function (DGF), kidneys from DCD donors have comparable short- and long-term graft survival. Livers from DCD donors have a higher likelihood of postoperative biliary complications such as diffuse ischemic cholangiopathy with intrahepatic biliary stricture and may also have a higher incidence of primary graft nonfunction and DGF compared to grafts from DND donors. Ischemic cholangiopathy occurs more frequently if the donor is older, is overweight, and has a prolonged ischemic period. Heart and lungs are susceptible to ischemia and only a few cases of the successful use of such grafts from DCD donors have been reported.
Extended Criteria Donor
Traditionally, DND organ donors are young and otherwise healthy until stricken by an isolated cerebral event or head injury (SCDs). As the numbers of patients waiting for transplant increase, many centers have extended donor criteria to minimize waiting-list mortality. Many terms, including suboptimal donor, marginal donor, inferior donor, nonstandard donor, and high-risk donor, have been used. The criteria that make up the ECD group are more elusive and evolving. Donor characteristics of ECDs vary from organ to organ but generally include advanced age, prolonged cold ischemia time, inferior organ function, and other comorbidities. However, donor risk is a relative term and should be described as a continuum, not a dichotomy of SCD and ECD. Therefore, donor risk index (DRI) has been developed for donors.
The kidney DRI has been developed using 10 donor characteristics ( Box 61.1 ). The kidney DRI can be converted into the kidney donor profile index (scale 1%-100%). A higher kidney donor profile index indicates a higher graft failure rate. The DRI has been defined for liver grafts. DRI is a quantitative assessment of the risk of graft failure associated with the donor. Liver DRI is calculated from eight donor characteristics ( Box 61.2 ). Despite an increased risk of graft failure, moderate-to-high acuity transplant candidates who receive a high DRI graft have a survival benefit compared with those remaining on the wait list. Calculation of the DRI can help physicians make a decision to accept or reject a donor offer; however, the calculation requires a projected cold ischemia time.
The following donor characteristics are used to calculate the kidney donor profile index
Age
Height
Weight
Ethnicity
History of hypertension
History of diabetes
Cause of death
Serum creatinine
Hepatitis C Virus status
Donation after circulatory death status
Age (four categories): >40, >50, >60, >70 years
Cause of death (two categories): cerebrovascular accident (lower risk) versus other
Race: African American (higher risk) versus other
Donation after circulatory death: yes or no
Partial or split graft: yes or no
Height: increasing risk as height decreases below 170 cm
Regional or national share: yes or no
Cold ischemia time
The use of ECD or high-risk DRI grafts has implications on intraoperative management. In a study of liver transplantation, several donor characteristics are associated with a high incidence of intraoperative hyperkalemia in adults: DCD grafts, prolonged ischemia time, and prolonged donor hospital stay before procurements. ECD liver grafts are also associated with postreperfusion syndrome, intraoperative bleeding, and postoperative reoperation.
Management of Organ Donors Before Procurement
As previously discussed, various physiologic derangements are common in DND donors. If not treated, these derangements can lead to graft deterioration, resulting in organs unsuitable for transplantation. A discussion of treatment strategies follows.
Cardiovascular Management
Although both hypertension and hypotension are associated with neurologic death and can result in poor perfusion to the organs, hypotension is more profound and difficult to treat. Maintaining adequate intravascular volume is probably the most effective therapy for vasoplegia. No evidence demonstrates that a specific crystalloid solution is superior to another. Adequate resuscitation, as evidenced by a mean arterial pressure of 60 to 100 mm Hg, may decrease cytokine levels and increase the number of organs available for transplantation. Large doses of starch-based colloids should be avoided because they may be associated with DGF.
When hemodynamic stabilization is not achieved with fluid resuscitation, vasoactive drugs should be considered. Dopamine is most commonly used in this setting. If a large dose of dopamine is required, then a second vasoactive agent can be added. Dopamine and other catecholamines have beneficial antiinflammatory and immunomodulatory effects. Vasopressin is recommended as the initial therapy of choice for potential heart donors by the American College of Cardiology. Vasopressin reduces catecholamine requirements and is an effective treatment for diabetes insipidus.
For a potential heart donor, cardiac function should be assessed, with early interventions to improve the donor procurement rate. Echocardiography is useful since it can identify both functional and structural abnormalities. Functional abnormalities identified in the early stage can be managed before heart transplantation, whereas structural abnormalities may preclude transplantation. Coronary angiography is useful in older donors with suspected or known coronary artery disease. Myocardial damage caused by catecholamine storm may be prevented or attenuated by controlling cardiovascular responses, which may increase the number of heart transplants. However, large doses of norepinephrine are associated with increased cardiac graft dysfunction and increased recipient mortality.
Excessive intravascular fluid therapy may have detrimental effects and should be avoided in lung donors. Fluid restriction increases the number of lung grafts available for transplantation. Because this practice creates a conflict of interest on the basis of which organs will be procured, particularly between the lungs and kidneys, fluid management should be balanced to optimize overall donation potential. The goal is to maintain a euvolemic state and to maintain arterial blood pressure and cardiac output with the least amount of vasoactive support possible. Invasive hemodynamic monitoring may be used to guide intravascular fluid therapy.
Pulmonary Management
The lungs are vulnerable to injury and, consequently, are one of the most difficult organs to preserve. Only 15% to 25% of donated lungs are used in transplantation. Current pulmonary management for potential lung donors favors small tidal volume ventilation. The focus of pulmonary management is to recruit and retain lung units while limiting tidal volume and inspiratory pressure. This strategy is extrapolated from studies in acute respiratory distress syndrome. Specific approaches to ventilator management for the donor are variable, but a common approach is a low tidal volume (6-8 mL/kg), low fraction of inspired oxygen concentration (Fi O 2 ), and relatively high positive end-expiratory pressure (PEEP). Pulmonary recruitment maneuvers, using pressure-controlled ventilation and high PEEP (15 cm water), followed by a return to conventional volume-controlled ventilation with a lower PEEP, are recommended by others. The administration of aerosolized terbutaline increases alveolar fluid clearance via β-adrenergic stimulation. As previously discussed, a large amount of intravascular fluid and/or large-dose vasopressors are associated with impaired graft function in potential lung donors.
Adequate gas exchange and good oxygenation are the most important indicators of the functional quality of the lung. However, an initial Pa O 2 /Fi O 2 ratio less than 300 mm Hg should not be used as grounds for exclusion. Reversible processes such as secretions, pulmonary edema, and atelectasis can affect the Pa O 2 /Fi O 2 ratio. Bronchoscopy is generally performed to remove mucous plugs that are present.
Temperature
Since hypothalamic function and regulation of body temperature are lost, DND donors usually have initial hyperpyrexia followed by hypothermia. Donor hypothermia is also contributed by reduced metabolic rate and peripheral vasodilatation. Normothermia has been traditionally recommended before and during procurement by using active warming devices. A recent report from a prospective trial challenges this traditional temperature management before procurement. In this trial, organ donors were randomized into two targeted temperature groups: mild hypothermia (34°C-35°C) or normothermia (36.5°C-37.5°C). The hypothermia group is associated with a significantly lower rate of DGF after kidney transplantation. In a retrospective study, mild hypothermia is confirmed to reduce DGF, but not graft survival in kidney transplantation.
Hormones, Steroids, Electrolytes, and Glycemic Control
Hormonal deficiency is common in neurologic-dead donors and hormonal replacement is beneficial. Exogenous replacement of antidiuretic hormone in neurologic-dead donors improves graft function in kidney, liver, and cardiac recipients. Thyroid hormone replacement improves the number of organs transplanted per donor and cardiac recipient survival. However, most studies showing advantages to hormone supplement are retrospective; adequately powered randomized trials are lacking.
The systemic inflammatory response associated with neurologic death leads to pulmonary infiltration of neutrophils and the elevation of interleukins. The systemic inflammatory response of the donor is associated with graft failure and recipient mortality. Methylprednisolone administration can moderate the inflammatory response and may improve oxygenation, reduce lung water, and increase lung yield. Methylprednisolone administration can also decrease inflammation in the liver, heart, and kidney.
Intravascular volume replacement is essential in the donor management. An isotonic crystalloid (lactated Ringer solution or 0.9% saline) is the preferred choice. However, 0.9% saline may not be the best choice due to the development of hyperchloremic metabolic acidosis. Colloid solutions are appropriate for rapid intravascular volume expansion. Routine use of hydroxyethyl starch is not recommended since it is associated with potential acute kidney injury, and coagulopathy. After administering initial fluid to correct hypovolemia, hypernatremia should be treated by giving a hypotonic solution. Studies have demonstrated that donor hypernatremia (>155 mmol/L) is associated with poor post–liver transplant outcomes. Analysis of heart donors in Europe showed increased recipient mortality when donor sodium was less than 130 or greater than 170 mmol/L. Correction of severe hypernatremia before organ procurement appears to attenuate post–transplant liver dysfunction. Hyperglycemia in the donor is common and exacerbated by steroid therapy. Poor glucose control adversely affects donor renal function. Insulin management should target a glucose level between 120 and 180 mg/dL. Routine use of IV fluid containing dextrose is not recommended.
Donor Management Goals
Current recommendations stress the use of standardized donor management with specific preprocurement goals. The objective of donor management goals (DMGs) is to maintain cardiovascular, pulmonary, renal, and endocrine homeostasis. The primary hemodynamic goal is to maximize perfusion for organ preservation by ensuring adequate intravascular volume and cardiac output. Table 61.3 summarizes common goals reported by various studies and recommended by some committees. Studies have shown that compliance with predetermined goals significantly improves the number of organs procured and transplanted. Early achievement of DMGs is important. Donors with four or more organs transplanted per donor have significantly more individual DMGs met at the time of consent. Efforts should focus on early management in patients with catastrophic neurologic injury until the intent to donate is known. One study showed that only 15% of donors met DMGs at the time of consent, although the rate was higher immediately before organ procurement.
| Preset Clinical End Points | Six DMGs ∗ | Eight DMGs † | Ten DMGs ‡ |
|---|---|---|---|
| Mean arterial pressure (mm Hg) | ≥60 | 60–120 | 60–100 |
| Central venous pressure (mm Hg) | ≤10 (or serum osmolality 285-295 mmol/L) | 4–12 | 4–10 |
| Final sodium (mmol/L) | ≤155 | ≤155 | 135–160 |
| Pressors | ≤1 (1 plus vasopressin to treat DI is acceptable) | ≤1 or low dose | ≤1 and low dose |
| Pa O 2 (mm Hg) or Pa O 2 /Fi O 2 ratio | Pa O 2 ≥ 300 while on 100% oxygen (or Pa co 2 /Fi O 2 ratio > 3) | Final Pa O 2 > 100 | Pa O 2 /Fi O 2 ratio: >300 on PEEP = 5 cm H 2 O |
| Arterial blood gas: pH | 7.25–7.50 | 7.30–7.50 | 7.30–7.45 |
| Glucose (mg/dL) | ≤150 | <150 | |
| Urine output (mL/kg/h) in 4 h before procurement | 0.5–3.0 | 1–3 | |
| Ejection fraction of left ventricle | >50% | ||
| Hemoglobin (mg/dL) | >10 |
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