A survey of physicians' attitudes to transfusion practice in critically ill patients in the UK

Blood use in patients receiving intensive chemotherapy for acute leukemia or hematopoietic stem cell transplantation: the impact of a health system-wide patient blood management program

BACKGROUND

Little is published on patient blood management (PBM) programs in hematology. In 2008 Western Australia announced a health system-wide PBM program with PBM staff appointments commencing in November 2009. Our aim was to assess the impact this program had on blood utilization and patient outcomes in intensive chemotherapy for acute leukemia or hematopoietic stem cell transplantation.

STUDY DESIGN AND METHODS

A retrospective study of 695 admissions at two tertiary hospitals receiving intensive chemotherapy for acute leukemia or undergoing hematopoietic stem cell transplantation between July 2010 and December 2014 was conducted. Main outcomes included pre-red blood cell (RBC) transfusion hemoglobin (Hb) levels, single-unit RBC transfusions, number of RBC and platelet (PLT) units transfused per admission, subsequent day case transfusions, length of stay, serious bleeding, and in-hospital mortality.

RESULTS

Over the study period, the mean RBC units transfused per admission decreased 39% from 6.1 to 3.7 (p < 0.001), and the mean PLT units transfused decreased 35% from 6.3 to 4.1 (p < 0.001), with mean RBC and PLT units transfused for follow-up day cases decreasing from 0.6 to 0.4 units (p < 0.001). Mean pre-RBC transfusion Hb level decreased from 8.0 to 6.8 g/dL (p < 0.001), and single-unit RBC transfusions increased 39% to 67% (p < 0.001). This reduction represents blood product cost savings of AU$694,886 (US$654,007). There were no significant changes in unadjusted or adjusted length of stay, serious bleeding events, or in-hospital mortality over the study.

CONCLUSION

The health system-wide PBM program had a significant impact, reducing blood product use and costs without increased morbidity or mortality in patients receiving intensive chemotherapy for acute leukemia or hematopoietic stem cell transplantation.

Anemia and blood transfusion practices in the critically ill: a prospective cohort review

BACKGROUND

Nearly 75% of critically ill patients develop anemia in the intensive care unit (ICU). Anemia can be treated with red blood cell (RBC) transfusions, although evidence suggests that lower hemoglobin levels are tolerated in the critically ill. Despite such recommendations, variation exists in clinical practice.

METHODS

A prospective cohort was assessed for anemia and RBC transfusion practices in 100 consecutive adults admitted to our General Systems ICU.

RESULTS

The prevalence of anemia in this cohort was 98%. Mean blood loss via phlebotomy was 25+/-10.3 mL per patient per day. The RBC transfusion rate for the ICU stay was 40%, increasing to 70% in patients whose ICU stay was >7 days. The mean pretransfusion level of hemoglobin was 7.35+/-0.47 mg/dL for the total cohort, and 8.2+/-0.65 mg/dL for those with a history of cardiovascular disease.

CONCLUSION

Anemia was common in this critically ill cohort, with hemoglobin levels continuing to drop with ICU stay. Pretransfusion hemoglobin levels were lower than reported by others, yet the RBC transfusion rate was comparable. There was no association between anemia and phlebotomy practices in our ICU.

Determinants of red blood cell transfusions in a pediatric critical care unit: A prospective, descriptive epidemiological study*

OBJECTIVE

To determine the incidence and to characterize the determinants of red blood cell transfusions in critically ill children.

DESIGN

Prospective, descriptive epidemiologic study.

SETTING

A single-center, multidisciplinary, tertiary care level, university-affiliated, pediatric intensive care unit (PICU).

PATIENTS

Critically ill children.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 1,047 consecutive admissions over a 1-yr period, 985 were retained for study. At least one transfusion was given in 139 cases (14%). Incidence rate of transfusion was 304 transfusions/1,000 cases. Possible determinants of red blood cell transfusions were identified and prospectively monitored during PICU stay until a first transfusion event (transfused cases) or up until the time of death or discharge from PICU (nontransfused cases). Four significant determinants of a first red blood cell transfusion event were retained in the multivariate analysis (odds ratio, 95% confidence interval, p): a hemoglobin level <9.5 g/dL during PICU stay (13.26, 8.04-21.88, p < .001), an admission diagnosis of cardiac disease (8.07, 5.14-14.65, p < .001), an admission Pediatric Risk of Mortality score >10 (4.83, 2.33-10.04, p < .001), and the presence of multiple organ dysfunction syndrome during the stay (2.06, 1.18-3.57, p = .01).

CONCLUSION

A significant proportion of critically ill children receive at least one red blood cell transfusion during their PICU stay. Presence of anemia, cardiac disease, severe critical illness, and multiple organ dysfunction syndrome are the most significant determinants of red blood cell transfusions in PICU.

A retrospective study evaluating single-unit red blood cell transfusions in reducing allogeneic blood exposure

Although guidelines recommend the use of single-unit red blood cell (RBC) transfusions to minimize allogeneic blood exposure, clinical practice remains dominated by two-unit transfusions. This study assesses the potential impact of a single-unit transfusion policy on reducing RBC utilization. We performed a retrospective analysis of adult patients admitted to a tertiary care hospital who received one or two RBC units. In subjects transfused two units, the effect of one unit was estimated by dividing the change in haemoglobin by 2. The proportion of patients reaching a haemoglobin threshold of 70, 75, 80, 85 and 90 g L(-1) with a single RBC unit was estimated. Of 302 included patients, only 65 received a one-unit transfusion. Based on thresholds of > or = 90, > or = 80 and > or = 70 g L(-1), a single-unit transfusion would be sufficient in 42.0% (RRR = 0.54), 79.6% (RRR = 0.23) and 98.0% (RRR = 0.02) of cases, respectively. This corresponds to 0.21, 0.57 and 0.82 mean RBC units saved per patient. In the orthopaedic subpopulation, the mean RBC units saved are 0.53, 0.88 and 1.00 for the same haemoglobin targets. Adopting a policy of transfusing RBC in single-unit aliquots could significantly improve RBC utilization and decrease patient exposure to allogeneic blood.

Effect of intravenous hydroxyethyl starch on the accuracy of measuring hemoglobin concentration

STUDY OBJECTIVE

To determine if intravenous hydroxyethylstarch (HES) affects the accuracy of hemoglobin (Hb) measurements, as artificial colloids are known to increase red blood cell sedimentation rates.

DESIGN

Prospective, randomized study.

SETTING

Tertiary-care academic medical institution.

PATIENTS AND INTERVENTIONS

We randomized 40 surgical American Society of Anesthesiologists (ASA) physical status I and II patients undergoing preoperative autologous blood donation before elective orthopedic surgery. Patients were randomized to receive volume replacement with 500 mL of 6% HES 200,000/0.5 or 500 mL of electrolyte solution. Measurements of Hb concentration and leukocyte count were performed using an analyzer with a suction needle sampling from the bottom of the test tube. Measurements were performed after mixing and repeated after a 10-minute period of upright positioning of the tube (at rest).

MAIN RESULTS

In the study group that received HES, Hb levels were increased above baseline after resting (mean increase to 151% of baseline values, P < .01), whereas the leukocyte count was decreased (mean decrease to 39% of baseline values, P < .01). No difference between baseline and resting measurements were observed in patients who received intravenous crystalloids. In addition, we repeatedly measured the Hb concentration in an unstirred tube with and without the addition of HES. In blood samples containing HES, the Hb concentration was increased above baseline after 2.5 minutes of resting, compared with 30 minutes without HES addition (P < .05).

CONCLUSIONS

Mixing of test tube contents before sampling is critical for accurate measurement of the Hb concentration in the blood of patients who received intravenous HES.

Cost-effectiveness of recombinant human erythropoietin for reducing red blood cells transfusions in critically ill patients

OBJECTIVE

To examine the cost-effectiveness of using recombinant human erythropoietin (rHuEPO) to reduce red blood cells (RBC) transfusions in intensive care unit (ICU) patients.

METHODS

Decision analysis examining costs and effectiveness of using rHuEPO versus not using rHuEPO in a simulated adult medical/surgical/trauma (mixed) ICU. Two independent cost-effectiveness models were created based on the results of two multicenter studies that investigated the use of rHuEPO. Base case assumptions and estimates of effectiveness were obtained from these two studies. Mean cumulative doses of rHuEPO were 190,900 units and 102,400 units for studies 1 and 2, respectively. The models accounted for the deferral rate for allogeneic RBC transfusions, rHuEPO efficacy (the reduction in allogeneic RBC use), and adverse effects of rHuEPO and allogeneic RBC transfusions. Model estimates were obtained from published sources. Costs were expressed in 2002 US dollar (dollars) and effectiveness was measured using discounted quality-adjusted life-years (QALYs). A 3% discount rate was used. Probabilistic sensitivity analysis was conducted using second-order Monte Carlo simulation.

RESULTS

Incremental costs of using rHuEPO to reduce RBC transfusions amounted to 1918 dollars and 1439 dollars; incremental effectiveness values were 0.0563 QALYs and 0.0305 QALYs; and the cost-effectiveness ratios were 34,088 dollars and 47,149 dollars per QALY for studies 1 and 2, respectively. The model was most sensitive to the attributable risk of nosocomial bacterial infections per RBC unit. rHuEPO was cost-effective in 52.0% of the Monte Carlo simulations for a willingness to pay of 50,000 dollars/QALY.

CONCLUSION

rHuEPO appears to be cost-effective for reducing RBC transfusions in heterogeneous ICU populations, assuming RBC transfusions increase the risk of nosocomial bacterial infections.

Revisiting transfusion practices in critically ill patients

OBJECTIVE

The objective of this study was to characterize contemporary red cell transfusion practice in the critically ill and to examine changes in practice over time.

STUDY DESIGN

The authors conducted a scenario-based national survey.

STUDY POPULATION

This study consisted of Canadian critical care practitioners.

OUTCOME MEASURE

The authors evaluated transfusion thresholds in four hypothetical scenarios.

RESULTS

Of 343 eligible Canadian critical care physicians, 235 (68.5%) responded to the survey. Most respondents were general internists (57%) who had been in practice for an average of 11.1 (+/-7.1) yrs and worked most often in combined medical/surgical intensive care units. Transfusion thresholds differed significantly among the four scenarios (p < .0001). The proportion of respondents adopting a threshold of 70 g/L was 63% and 70% in the hypothetical scenarios of trauma and septic shock compared with 16% and 3% who adopted the same threshold for scenarios involving patients with stable gastrointestinal hemorrhage and postoperative myocardial infarction, respectively. Fifteen percent of respondents identified transfusion thresholds exceeding 100 g/L for the postoperative myocardial infarction scenario, and 7% identified this threshold for the gastrointestinal hemorrhage scenario. Only 0.4% of respondents adopted a 100-g/L threshold for the two remaining scenarios. There was a significant decrease in transfusion thresholds in all four scenarios (p < .001) since the administration of a previous survey in 1993. The reported use of single-unit transfusions was 56% in 2002 vs. 10% in 1993. Eighty-five percent of physicians stated that they had modified their approach to transfusion, primarily in response to the publication of a major Canadian clinical trial and institutional guidelines.

CONCLUSIONS

Canadian physicians appear to have adopted lower transfusion triggers and an increase in the use of single-unit red cell transfusion.

Use of exogenous erythropoietin in critically ill patients

OBJECTIVE

Review the literature regarding the use of recombinant human erythropoietin (rHuEPO) to prevent red blood cell (RBC) transfusion in critically ill patients.

DATA SOURCES

A computerized search of MEDLINE and EMBASE from 1966 through June 2003 was conducted using the terms erythropoietin, anemia, hemoglobin, critical care, intensive care, surgery, trauma, burn, and transfusion. References of selected articles were reviewed. A manual search of critical care, surgery, trauma, burn, hematology, and pharmacy journals was conducted to identify relevant abstracts.

RESULTS

Six randomized studies have evaluated exogenous administration of erythropoietin to prevent RBC transfusions in critically ill patients. Studies vary with respect to rHuEPO dosage regimens, dose of concurrently administered iron, patient characteristics, and transfusion thresholds. Administration of rHuEPO rapidly produces erythropoiesis to reduce the need for RBC transfusions. The largest study conducted to date used weekly rHuEPO administration and found a modest decrease in transfusion requirements although the time to first transfusion was delayed. Reduced intensive care unit (ICU) length of stay (LOS) was shown in only one study of surgical/trauma patients. Reduced LOS after ICU discharge was found in another study of severely ill patients (APACHE II score >22). Other clinical outcomes were not altered by rHuEPO use. No adverse events were associated with rHuEPO use although studies were not designed to evaluate safety.

CONCLUSIONS

rHuEPO reduces the need for transfusions. A cost-effectiveness analysis of rHuEPO for this indication is needed. Defining an optimal dosage regimen, identifying patients most likely to respond to rHuEPO, and determining risk factors for ICU associated anaemia would provide information for appropriate rHuEPO utilization.

A survey of physicians' attitudes toward blood transfusion in patients undergoing cesarean section

OBJECTIVE

This study was undertaken to evaluate the attitude of anesthesiologists and gynecologists to the use of blood during cesarean section operation and, on the basis of the results, to ascertain the need for improvement of current transfusion guidelines.

STUDY DESIGN

A scenario-based survey was performed.

RESULTS

The response rate was 94% (327/347) among anesthesiologists and 91% (355/391) among gynecologists. The majority of responders selected a hemoglobin threshold ranging from 7.5 to 8.5 g/dL (62%). Threshold hemoglobin concentration differed significantly (P<.001) between anesthesiologists (median, 7.5 g/dL) and gynecologists (median, 8 g/dL). At that threshold, 56% of anesthesiologists compared with 86% of gynecologists administered 2 units of blood (P<.05). When transfusing packed cells, most practitioners would give 2 units regardless of the transfusion threshold.

CONCLUSION

Our findings demonstrate differing approaches to current transfusion protocols. Transfusion consensus recommendations should be improved and unified to enhance red blood cell transfusion practices for relatively young and healthy patients undergoing anesthesia and surgery.

Techniques for assessing and achieving fluid balance in acute renal failure

Fluid therapy, together with attention to oxygen supply, is the cornerstone of resuscitation in all critically ill patients. Hypovolemia results in inadequate blood flow to meet the metabolic requirements of the tissues and must be treated urgently to avoid the complication of progressive organ failure, including acute renal failure. The kidney plays a critical role in body fluid homeostasis. Renal dysfunction disturbs this homeostasis and requires special attention to issues of fluid balance and fluid overload. In addition, fluid therapy is the only treatment that has been shown to be effective in the prevention of acute renal failure. Special attention to volume status is therefore required in patients at risk for acute renal failure. Hypovolemia is also a major causal factor of morbidity during hemodialysis and may contribute to further renal insults. Although the importance of fluid management is generally recognized, the choice of fluid, the amount, and assessment of fluid status are controversial. As the choice of fluids becomes wider and monitoring devices become more sophisticated, the controversy increases. This article provides an overview of the concept of fluid management in the critically ill patient with acute renal failure.