Lewis J. Kaplan

Red blood cell transfusion: A Clinical practice guideline from the AABB

DESCRIPTION Although approximately 85 million units of red blood cells (RBCs) are transfused annually worldwide, transfusion practices vary widely. The AABB (formerly, the American Association of Blood Banks) developed this guideline to provide clinical recommendations about hemoglobin concentration thresholds and other clinical variables that trigger RBC transfusions in hemodynamically stable adults and children. METHODS These guidelines are based on a systematic review of randomized clinical trials evaluating transfusion thresholds. We performed a literature search from 1950 to February 2011 with no language restrictions. We examined the proportion of patients who received any RBC transfusion and the number of RBC units transfused to describe the effect of restrictive transfusion strategies on RBC use. To determine the clinical consequences of restrictive transfusion strategies, we examined overall mortality, nonfatal myocardial infarction, cardiac events, pulmonary edema, stroke, thromboembolism, renal failure, infection, hemorrhage, mental confusion, functional recovery, and length of hospital stay. RECOMMENDATION 1: The AABB recommends adhering to a restrictive transfusion strategy (7 to 8 g/dL) in hospitalized, stable patients (Grade: strong recommendation; high-quality evidence). RECOMMENDATION 2: The AABB suggests adhering to a restrictive strategy in hospitalized patients with preexisting cardiovascular disease and considering transfusion for patients with symptoms or a hemoglobin level of 8 g/dL or less (Grade: weak recommendation; moderate-quality evidence). RECOMMENDATION 3: The AABB cannot recommend for or against a liberal or restrictive transfusion threshold for hospitalized, hemodynamically stable patients with the acute coronary syndrome (Grade: uncertain recommendation; very low-quality evidence). RECOMMENDATION 4: The AABB suggests that transfusion decisions be influenced by symptoms as well as hemoglobin concentration (Grade: weak recommendation; low-quality evidence).

Initial pH, base deficit, lactate, anion gap, strong ion difference, and strong ion gap predict outcome from major vascular injury

Objective:This study determines whether acid-base data obtained in the emergency department correlate with outcome from major vascular injury. Design:Observational, retrospective record review of trauma patients requiring vascular repair (torso or extremity, January 1988 to December 1997). Data included age, Injury Severity Score, injury mechanism, survival, laboratory profiling, calculated anion gap, strong ion difference, and strong ion gap. Patients were divided into survivors and nonsurvivors with comparison by Student’s t-test; significance was assumed for p ≤ .05. Multivariate logistic regression was used for further analysis of univariate predictors of mortality, and receiver operator characteristic curves were generated for mortality from each variable. Setting:Urban level I trauma facility. Patients:Trauma patients requiring vascular repair of torso or extremity injury. Interventions:None. Measurements and Main Results:Both nonsurvivors (n = 64) and survivors (n = 218) were similar with respect to age (31 ± 9 vs. 31.5 ± 10.5, p = 0.15) and injury mechanics (81% penetrating in survivors vs. 83% penetrating in nonsurvivors, p = .71). Non-survivor Injury Severity Score exceeded that of survivors (27.5 ± 7.8 vs. 12.4 ± 9.4, p < .001). Nonsurvivor pH (7.06 ± 0.15 vs. 7.34 ± 0.08, p < .001) and apparent strong ion difference (31.38 ± 4.39 vs. 37.53 ± 3.86, p < .001) were significantly lower, whereas nonsurvivor standard base excess (−17.9 ± 5.1 vs. −2.9 ± 4.4 mEq/L, p < .001), lactate (11.1 ± 3.6 vs. 3.6 ± 1.5 mmol/L, p < .001), anion gap (28.2 ± 4.1 vs. 15.6 ± 3.1, p < .001), and strong ion gap (10.8 ± 3.2 vs. 2.4 ± 1.8, p < .001) were higher. All but one nonsurvivor had initial emergency department pH ≤7.26, standard base excess ≤ −7.3 mEq/L, lactate ≥5 mmol/L, and strong ion gap ≥5 mEq/L. All of the acid-base descriptors were strongly associated with outcome, but the strong ion gap discriminated most strongly with an area under the receiver operator characteristic of 0.991 (95% confidence interval, 0.972– 0.998). Conclusions:The initial emergency department acid-base variables of pH, base deficit, lactate, anion gap, apparent strong ion difference, and strong ion gap discriminate survivors from non-survivors of major vascular injury. The strong ion gap is most strongly predictive of mortality following major vascular trauma.

Clinical practice guidelines from the AABB: Red blood cell transfusion thresholds and storage

Importance More than 100 million units of blood are collected worldwide each year, yet the indication for red blood cell (RBC) transfusion and the optimal length of RBC storage prior to transfusion are uncertain. Objective To provide recommendations for the target hemoglobin level for RBC transfusion among hospitalized adult patients who are hemodynamically stable and the length of time RBCs should be stored prior to transfusion. Evidence Review Reference librarians conducted a literature search for randomized clinical trials (RCTs) evaluating hemoglobin thresholds for RBC transfusion (1950-May 2016) and RBC storage duration (1948-May 2016) without language restrictions. The results were summarized using the Grading of Recommendations Assessment, Development and Evaluation method. For RBC transfusion thresholds, 31 RCTs included 12 587 participants and compared restrictive thresholds (transfusion not indicated until the hemoglobin level is 7-8 g/dL) with liberal thresholds (transfusion not indicated until the hemoglobin level is 9-10 g/dL). The summary estimates across trials demonstrated that restrictive RBC transfusion thresholds were not associated with higher rates of adverse clinical outcomes, including 30-day mortality, myocardial infarction, cerebrovascular accident, rebleeding, pneumonia, or thromboembolism. For RBC storage duration, 13 RCTs included 5515 participants randomly allocated to receive fresher blood or standard-issue blood. These RCTs demonstrated that fresher blood did not improve clinical outcomes. Findings It is good practice to consider the hemoglobin level, the overall clinical context, patient preferences, and alternative therapies when making transfusion decisions regarding an individual patient. Recommendation 1: a restrictive RBC transfusion threshold in which the transfusion is not indicated until the hemoglobin level is 7 g/dL is recommended for hospitalized adult patients who are hemodynamically stable, including critically ill patients, rather than when the hemoglobin level is 10 g/dL (strong recommendation, moderate quality evidence). A restrictive RBC transfusion threshold of 8 g/dL is recommended for patients undergoing orthopedic surgery, cardiac surgery, and those with preexisting cardiovascular disease (strong recommendation, moderate quality evidence). The restrictive transfusion threshold of 7 g/dL is likely comparable with 8 g/dL, but RCT evidence is not available for all patient categories. These recommendations do not apply to patients with acute coronary syndrome, severe thrombocytopenia (patients treated for hematological or oncological reasons who are at risk of bleeding), and chronic transfusion-dependent anemia (not recommended due to insufficient evidence). Recommendation 2: patients, including neonates, should receive RBC units selected at any point within their licensed dating period (standard issue) rather than limiting patients to transfusion of only fresh (storage length: <10 days) RBC units (strong recommendation, moderate quality evidence). Conclusions and Relevance Research in RBC transfusion medicine has significantly advanced the science in recent years and provides high-quality evidence to inform guidelines. A restrictive transfusion threshold is safe in most clinical settings and the current blood banking practices of using standard-issue blood should be continued.

The status of massive transfusion protocols in United States trauma centers: massive transfusion or massive confusion?

BACKGROUND: Massive transfusion protocol (MTP) utilization and makeup is unknown.

Clinical review: Acid–base abnormalities in the intensive care unit – part II

Acid–base abnormalities are common in the critically ill. The traditional classification of acid–base abnormalities and a modern physico-chemical method of categorizing them will be explored. Specific disorders relating to mortality prediction in the intensive care unit are examined in detail. Lactic acidosis, base excess, and a strong ion gap are highlighted as markers for increased risk of death.

Start with a Subjective Assessment of Skin Temperature to Identify Hypoperfusion in Intensive Care Unit Patients

OBJECTIVE To determine whether physical examination alone or in combination with biochemical markers can accurately diagnose hypoperfusion. METHODS Data from 264 consecutive surgical intensive care unit patients were collected by two intensivists and included extremity temperature, vital signs, arterial lactate, arterial blood gases, hemoglobin, and pulmonary artery catheter values with derived indices. Days of data were divided into data collected from patients with cool extremities (cool skin temperature [CST] group) versus warm extremities (warm skin temperature [WST] group). Values are means +/- SD. Comparisons between groups were made by two-tailed unpaired t test; significance was assumed for p < or = 0.05. RESULTS There were 328 days of observations in the CST group versus 439 in the WST group. There were no differences (p > 0.05) between CST and WST data with regard to heart rate (107 +/- 14 vs. 99 +/- 19 beats/min), systolic blood pressure (118 +/- 24 vs. 127 +/- 28 mm Hg), diastolic blood pressure (57 +/- 14 vs. 62 +/- 15 mm Hg), pulmonary artery occlusion pressure (14 +/- 6 vs. 16 +/- 5 mm Hg), Fio2 (0.48 +/- 0.7 vs. 0.45 +/- 0.2), hemoglobin (8.8 +/- 1.6 vs. 9.3 +/- 1.3 g/dL), Pco2 (44.3 +/- 11.8 vs. 40.7 +/- 9.2 mm Hg), or Po2 (96.4 +/- 12.6 vs. 103.8 +/- 22.2 mm Hg). However, cardiac output (5.3 +/- 2.2 vs. 8.2 +/- 2.6 L/min), cardiac index (2.9 +/- 1.2 vs. 4.3 +/- 1.2 L/min/m2), pH (7.32 +/- 0.2 vs. 7.39 +/- 0.07), TCO2 (19.5 +/- 3.1 vs. 25.1 +/- 4.8 mEq/L), and Svo2 (60.2 +/- 4.4% vs. 68.2 +/- 7.8%) were all significantly lower (p < 0.05) in CST patients compared with WST patients. By comparison, lactate (4.7 +/- 1.5 vs. 2.2 +/- 1.6 mmol/L, p < 0.05) was significantly elevated in patients with cool extremities. CONCLUSION Combining physical examination with serum bicarbonate and arterial lactate identifies patients with hypoperfusion as defined by low Svo2 and cardiac index. Hypoperfusion may occur despite supranormal cardiac indices. Patients with cool extremities and elevated lactate levels may benefit from a pulmonary artery catheter to guide but not initiate therapy.

Contrast-induced nephropathy in elderly trauma patients.

BACKGROUND Computed tomography (CT) is the gold standard for the identification of occult injuries, but the intravenous (IV) contrast used in CT scans is potentially nephrotoxic. Because elderly patients have decreased renal function secondary to aging and chronic disease, we sought to determine the rate of acute kidney injury (AKI) in elderly trauma patients exposed to IV contrast. METHODS Medical records of patients older than 55 years evaluated at a level-one trauma center between January 2003 and July 2008 were reviewed. Contrast was nonionic, isosmolar, and administered in standard volumes. Groups were based on administration of contrast. AKI was defined as a 25% relative or 0.5 mg/dL absolute increase in serum creatinine within 72 hours of presentation [corrected]. RESULTS During the study period 1,371 patients older than 55 years were evaluated, and 1,152 met the inclusion criteria. CT was performed on 1,071 patients (96%); 71% of this group received IV contrast. There was no significant difference between the contrast and noncontrast groups in terms of baseline characteristics. Criteria for AKI were satisfied in 2.1% of all patients, including 1.9% the contrast group versus 2.4% in the noncontrast group. AKI diagnosed within 72 hours of patient presentation was an independent risk factor for in-hospital mortality and prolonged length of stay. CONCLUSIONS IV contrast media in elderly trauma patients is not associated with an increased risk of AKI. Development of AKI within 72 hours of admission is associated with mortality and increased length of stay.

An Official American Thoracic Society/American Association of Critical-Care Nurses/American College of Chest Physicians/Society of Critical Care Medicine Policy Statement: The Choosing Wisely® Top 5 List in Critical Care Medicine

RATIONALE The high costs of health care in the United States and other developed nations are attributable, in part, to overuse of tests, treatments, and procedures that provide little to no benefit for patients. To improve the quality of care while also combating this problem of cost, the American Board of Internal Medicine Foundation developed the Choosing Wisely Campaign, tasking professional societies to develop lists of the top five medical services that patients and physicians should question. OBJECTIVES To present the Critical Care Societies Collaboratives Top 5 list in Critical Care Medicine and describe its development. METHODS Each professional society in the Collaborative nominated members to the Choosing Wisely task force, which established explicit criteria for evaluating candidate items, generated lists of items, performed literature reviews on each, and sought external input from content experts. Task force members narrowed the list to the Top 5 items using a standardized scoring system based on each items likely overall impact and merits on the five explicit criteria. MEASUREMENTS AND MAIN RESULTS From an initial list of 58 unique recommendations, the task force proposed a Top 5 list that was ultimately endorsed by each Society within the Collaborative. The five recommendations are: (1) do not order diagnostic tests at regular intervals (such as every day), but rather in response to specific clinical questions; (2) do not transfuse red blood cells in hemodynamically stable, nonbleeding ICU patients with an Hb concentration greater than 7 g/dl; (3) do not use parenteral nutrition in adequately nourished critically ill patients within the first 7 days of an ICU stay; (4) do not deeply sedate mechanically ventilated patients without a specific indication and without daily attempts to lighten sedation; and (5) do not continue life support for patients at high risk for death or severely impaired functional recovery without offering patients and their families the alternative of care focused entirely on comfort. CONCLUSIONS These five recommendations provide a starting point for clinicians and patients to make decisions leading to higher-quality, lower-cost care. Future work is needed to promote adherence to these recommendations and to develop additional ways for intensive care clinicians to take leadership in reining in health-care costs.

Bovine polymerized hemoglobin (hemoglobin-based oxygen carrier-201) resuscitation in three swine models of hemorrhagic shock with militarily relevant delayed evacuation--effects on histopathology and organ function.

Objective:To test our hypothesis that hemoglobin-based oxygen carrier (HBOC)-201 resuscitation in hemorrhagic shock (HS) will not lead to increased organ injury and dysfunction. Design:Three swine HS models simulating military-relevant delayed evacuation: a) moderate controlled HS, b) severe controlled HS, and c) severe uncontrolled HS. Setting:Military research laboratory. Subjects:Swine. Interventions:Swine were anesthetized/intubated and instrumented. To induce HS, in two controlled hemorrhage experiments, 40% (moderate controlled HS) or 55% (severe controlled HS) of blood volume was withdrawn; in an uncontrolled HS experiment, the liver was crushed/lacerated. During a 4-hr “prehospital phase,” pigs were resuscitated with HBOC-201 (HBOC) or Hextend (HEX) or were nonresuscitated (NON). Upon “hospital arrival,” liver injury was repaired (severe uncontrolled HS), blood or saline was infused, hemodynamics were monitored, and blood was collected. Upon animal death and/or 72 hrs, necropsy was followed by histopathologic evaluation of organ injury (hematoxylin and eosin, electron microscopy) and immunohistochemistry of oxidative potential (3-nitrotyrosine). Significance (p < .05) was assessed by Kruskal-Wallis, analysis of variance/Bonferroni, and mixed procedure tests. Measurements and Main Results:Survival was significantly higher with HBOC than HEX only with severe uncontrolled HS (p = .002). Myocardial necrosis/fibroplasia, fluid requirements, cardiac output, and cardiac enzymes were generally similar or lower in HBOC than HEX pigs, but creatine kinase-MB (but not creatine kinase-MB/creatine kinase ratio) was higher with HBOC in moderate controlled HS. Alveolar/interstitial pulmonary edema was similar with HBOC and HEX, but Po2 was higher with HBOC in severe uncontrolled HS. Jejunal villar epithelial and hepatocellular necrosis were similarly minimal to moderate in all groups. Minimal biliary changes occurred exclusively with HBOC. Aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase were generally higher with HBOC than HEX. Mild renal papillary injury occurred more frequently with HBOC, but consistent patterns for urine output, blood urea nitrogen, and creatinine, were not seen. The 3-nitrotyrosine staining intensity was not different. Conclusions:In comparison with hetastarch, HBOC-201 resuscitation of swine with HS increased survival (with severe HS), did not increase evidence of oxidative potential, and had histopathologic and/or functional effects on organs that were clinically equivocal (myocardium, lungs, hepatic parenchyma, jejunum, and renal cortex/medulla) and potentially adverse (hepatobiliary and renal papilla). The effects of HBOC-201-resuscitation in HS should be corroborated in controlled clinical trials.

Fluids, pH, ions and electrolytes.

Purpose of reviewSignificant attention has been recently focused on both maintenance fluid and resuscitation fluid use in critical care. Accordingly, a focused review of the properties of crystalloid and colloid fluids, their expected benefits, and potential deleterious side effects is appropriate and timely. Recent findingsDespite their ubiquitous use, well described side effects, and ability to be titrated to a physiologic endpoint, fluids are rarely considered in a fashion similar to other pharmacologic agents. Understanding their physical and chemical properties allows the clinician to understand, anticipate and deliberately harness their expected impact on acid–base balance. Expanded insights into the pathogenesis of common acid–base disorders may be gleaned from utilizing a physicochemical approach that allows the precise quantification of the ionic species that impact pH. SummaryThis focused review further enables the clinician to appropriately investigate, modify, and optimize bedside clinical care related to fluid and acid–base management.