Debate: transfusing to normal haemoglobin levels will not improve outcome

Transfusion Requirement in Burn Care Evaluation (TRIBE): A Multicenter Randomized Prospective Trial of Blood Transfusion in Major Burn Injury

OBJECTIVE

Our objective was to compare outcomes of a restrictive to a liberal red cell transfusion strategy in 20% or more total body surface area (TBSA) burn patients. We hypothesized that the restrictive group would have less blood stream infection (BSI), organ dysfunction, and mortality.

BACKGROUND

Patients with major burns have major (>1 blood volume) transfusion requirements. Studies suggest that a restrictive blood transfusion strategy is equivalent to a liberal strategy. However, major burn injury is precluded from these studies. The optimal transfusion strategy in major burn injury is thus needed but remains unknown.

METHODS

This prospective randomized multicenter trial block randomized patients to a restrictive (hemoglobin 7-8 g/dL) or liberal (hemoglobin 10-11 g/dL) transfusion strategy throughout hospitalization. Data collected included demographics, infections, transfusions, and outcomes.

RESULTS

Eighteen burn centers enrolled 345 patients with 20% or more TBSA burn similar in age, TBSA burn, and inhalation injury. A total of 7054 units blood were transfused. The restrictive group received fewer blood transfusions: mean 20.3 ± 32.7 units, median = 8 (interquartile range: 3, 24) versus mean 31.8 ± 44.3 units, median = 16 (interquartile range: 7, 40) in the liberal group (P < 0.0001, Wilcoxon rank sum). BSI incidence, organ dysfunction, ventilator days, and time to wound healing (P > 0.05) were similar. In addition, there was no 30-day mortality difference: 9.5% restrictive versus 8.5% liberal (P = 0.892, χ test).

CONCLUSIONS

A restrictive transfusion strategy halved blood product utilization. Although the restrictive strategy did not decrease BSI, mortality, or organ dysfunction in major burn injury, these outcomes were no worse than the liberal strategy (Clinicaltrials.gov identifier NCT01079247).

Intensive care and invasive ventilation in the elderly patient, implications of chronic lung disease and comorbidities

Aims: Elderly patients have an increasing prevalence of illness that requires consideration of critical care and invasive ventilatory support. Although critical care of even the very elderly can provide value, with increasing age the potential risks of treatment and diminishing returns with respect to quality and quantity of life result in a need for careful evaluation. Variable combinations of impaired organ function, active disease and residual pathology from past disease and injury all affect critical care, with the consequence that the elderly are a very heterogeneous population. Recognizing that critical care is a limited resource, it is important to identify patients who may be at increased risk or least likely to benefit from treatment. Patients with functional impairments, nutritional deficiencies and multiple comorbidities may be at highest risk of poor outcomes. Those with very severe disease, extreme age and requirements for prolonged ventilatory support have high in-hospital mortality. Functional impairments, comorbidities and severity of illness are usually more important considerations than chronologic age. The objective of this review is to identify how common problems of the elderly affect critical care and decisions concerning use of invasive ventilatory support.

Anaemia and pregnancy: Anaesthetic implications

Anaemia in pregnancy defined as haemoglobin (Hb) level of < 10 gm/dL, is a qualitative or quantitative deficiency of Hb or red blood cells in circulation resulting in reduced oxygen (O2)- carrying capacity of the blood. Compensatory mechanisms in the form of increase in cardiac output (CO), PaO(2), 2,3 diphosphoglycerate levels, rightward shift in the oxygen dissociation curve (ODC), decrease in blood viscosity and release of renal erythropoietin, get activated to variable degrees to maintain tissue oxygenation and offset the decreases in arterial O(2) content. Parturients with concomitant medical diseases or those with acute ongoing blood losses may get decompensated, leading to serious consequences like right heart failure, angina or tissue hypoxemia in severe anaemia. Preoperative evaluation is aimed at assessing the severity and cause of anaemia. The concept of an acceptable Hb level varies with the underlying medical condition, extent of physiological compensation, the threat of bleeding and ongoing blood losses. The main anaesthetic considerations are to minimize factors interfering with O(2) delivery, prevent any increase in oxygen consumption and to optimize the partial pressure of O(2) in the arterial blood. Both general anaesthesia and regional anaesthesia can be employed judiciously. Monitoring should focus mainly on the adequacy of perfusion and oxygenation of vital organs. Hypoxia, hyperventilation, hypothermia, acidosis and other conditions that shift the ODC to left should be avoided. Any decrease in CO should be averted and aggressively treated.

What's new in critical care of the burn-injured patient?

The number of cases of mortality after burn injury continues to decline, in part because of advances in respiratory, fluid, and sepsis management. However, care needs to be exercised in the application of these new techniques and technologies, many of which have never been assessed or have been incompletely studied in patients who have burn injury. Use of any of these advances in critical care needs to be individualized for any given patient and altered based on the patient's response to therapy. Future advances in the critical care of burns will require multicenter prospective trials at dedicated burn centers to define the optimal therapy for the patient who has burn injury.

Blood transfusions are associated with increased risk for development of sepsis in severely burned pediatric patients

OBJECTIVE

To determine the risk of developing sepsis following transfusion of blood products in severely burned pediatric patients.

DESIGN

Retrospective, cohort study.

SETTING

Shriners Hospital for Children and University Hospital.

PATIENTS

Severely burned pediatric patients with >30% total body surface area (TBSA) burn.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred seventy-seven pediatric burn patients over a period of 7 yrs (1997-2004) were included in the study, with 25 patients being septic at admission and therefore excluded. Patients were stratified according to TBSA burn and presence or absence of inhalation injury. The amounts of packed red blood cells (RBCs) and fresh frozen plasma (FFP) were recorded during hospital stay before the development of sepsis. Blood product administration was normalized for the number of surgeries and divided into two groups: high (RBCs>20/FFP>5) or low (RBCs<20/FFP<5) amount of blood products. Sepsis was diagnosed based on the criteria set by the Society of Critical Care Medicine in conjunction with positive blood culture or presence of organisms in the organs at autopsy. By stratifying the groups into low and high blood transfusion, we found that patients with >60% TBSA burn with inhalation injury have an 8% risk of developing sepsis in the low RBC group, which increases to 58% in the high RBC group (p<.05). Similar results were found for RBCs per operation, FFP, and FFP per operation (p<.05). There were no differences in age and gender between groups.

CONCLUSIONS

Pediatric burn suffering from a 60% TBSA burn with concomitant inhalation injury are more likely to develop sepsis if they are given high amounts of blood products, indicating an immunocompromised state following blood transfusion.

Effect of blood transfusion on outcome after major burn injury: a multicenter study

OBJECTIVE

To delineate blood transfusion practices and outcomes in patients with major burn injury.

CONTEXT

Patients with major burn injury frequently require multiple blood transfusions; however, the effect of blood transfusion after major burn injury has had limited study.

DESIGN

Multicenter retrospective cohort analysis.

SETTING

Regional burn centers throughout the United States and Canada.

PATIENT POPULATION

Patients admitted to a participating burn center from January 1 through December 31, 2002, with acute burn injuries of >or=20% total body surface area.

OUTCOMES MEASURED

Outcome measurements included mortality, number of infections, length of stay, units of blood transfused in and out of the operating room, number of operations, and anticoagulant use.

RESULTS

A total of 21 burn centers contributed data on 666 patients; 79% of patients survived and received a mean of 14 units of packed red blood cells during their hospitalization. Mortality was related to patient age, total body surface area burn, inhalation injury, number of units of blood transfused outside the operating room, and total number of transfusions. The number of infections per patient increased with each unit of blood transfused (odds ratio, 1.13; p<.001). Patients on anticoagulation during hospitalization received more blood than patients not on anticoagulation (16.3+/-1.5 vs. 12.3+/-1.5, p<.001).

CONCLUSIONS

The number of transfusions received was associated with mortality and infectious episodes in patients with major burns even after factoring for indices of burn severity. The utilization of blood products in the treatment of major burn injury should be reserved for patients with a demonstrated physiologic need.

Blood transfusion in burns: what do we do?

Over 11 million units of blood are transfused yearly in the United States. Although blood transfusion is common in burns, data are lacking on appropriate transfusion thresholds. The purpose of the study was to identify current burn center physician blood transfusion practices. A 30-question survey of blood transfusion practices was developed and sent to burn center directors. The survey assessed demographics, burn experience, and blood transfusion thresholds. Physicians were asked to list factors affecting their blood transfusion thresholds and then to give their blood transfusion threshold for patients based on age and percent burn. The final section presents three case scenarios with alterations in one physiological parameter to assess the effect on transfusion thresholds. A total of 55 of the 180 surveys (31%) were returned. Mean number of burn beds was 15.7 +/- 1.4, with 264 +/- 25 burn admissions per year. The respondents had been in burn care for 15.9 +/- 1.4 years. Their mean hemoglobin transfusion threshold was 8.12 +/- 1.7 g/dl. The most frequent reasons for transfusion were ongoing blood loss (22%), anemia (20%), hypoxia (13%), and cardiac disease (12%). Inhalation injury influenced the decision to transfuse blood in 34%. The hemoglobin level below which respondents would transfuse blood increased with increasing TBSA burn, history of cardiac disease, acute respiratory distress syndrome, and age. Blood transfusion thresholds in burns vary based on burn percentage, age, and presence of cardiac disease. To date, no standard of care exists for blood transfusions in burns. Future prospective studies are needed to determine the appropriate use of blood in burns.