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Restrictive versus liberal transfusion strategies for older mechanically ventilated critically ill patients: a
Timothy S Walsh1, Julia A Boyd, Douglas Watson
11Department of Critical Care and Centre for Inflammation Research, Edinburgh University, Little France Crescent, Edinburgh, Scotland. 2Edinburgh Clinical Trials Unit, Western General Hospital, Edinburgh, Scotland. 3Better Blood Transfusion, National Blood Transfusion Service, Gartnavel, Glasgow, Scotland. 4Centre for Population Health Sciences, Edinburgh University, Edinburgh, Scotland. 5Barts and The London School of Medicine & Dentistry, Queen Marys University of London, London, UK. 6Department of Anaesthesia and Intensive Care, Western General Hospital, Crewe Toll, Edinburgh, Scotland. 7Department of Anaesthetics, Stirling Royal Infirmary, Stirling, Scotland. 8Department of Anaesthesia and Critical Care, Ninewells Hospital & Medical School, Dundee, Scotland. 9Guy's & St Thomas' NHS Foundation Trust, London, UK.
Objectives:
To compare hemoglobin concentration (Hb), RBC use, and patient outcomes when restrictive or liberal blood transfusion strategies are used to treat anemic (Hb≤90 g/L) critically ill patients of age≥55 years requiring≥4 days of mechanical ventilation in ICU.
Design:
Parallel-group randomized multicenter pilot trial.
Setting:
Six ICUs in the United Kingdom participated between August 2009 and December 2010.
Patients:
One hundred patients (51 restrictive and 49 liberal groups).
Interventions:
Patients were randomized to a restrictive (Hb trigger, 70 g/L; target, 71-90 g/L) or liberal (90 g/L; target, 91-110 g/L) transfusion strategy for 14 days or the remainder of ICU stay, whichever was longest.
Measurements And Main Results:
Baseline comorbidity rates and illness severity were high, notably for ischemic heart disease (32%). The Hb difference among groups was 13.8 g/L (95% CI, 11.5-16.0 g/L); p<0.0001); mean Hb during intervention was 81.9 (SD, 5.1) versus 95.7 (6.3) g/L; 21.6% fewer patients in the restrictive group were transfused postrandomization (p<0.001) and received a median 1 (95% CI, 1-2; p=0.002) fewer RBC units. Protocol compliance was high. No major differences in organ dysfunction, duration of ventilation, infections, or cardiovascular complications were observed during intensive care and hospital follow-up. Mortality at 180 days postrandomization trended toward higher rates in the liberal group (55%) than in the restrictive group (37%); relative risk was 0.68 (95% CI, 0.44-1.05; p=0.073). This trend remained in a survival model adjusted for age, gender, ischemic heart disease, Acute Physiology and Chronic Health Evaluation II score, and total non-neurologic Sequential Organ Failure Assessment score at baseline (hazard ratio, 0.54 [95% CI, 0.28-1.03]; p=0.061).
Conclusions:
A large trial of transfusion strategies in older mechanically ventilated patients is feasible. This pilot trial found a nonsignificant trend toward lower mortality with restrictive transfusion practice.
