Critically Appraised Topic: Therapy A Multicenter, Randomized ...

Critically Appraised Topic: TherapyA Multicenter, Randomized, Controlled Clinical Trial of Transfusion Requirementsin Critical CarePaul C. Herbert et al, The New England Journal of Medicine, 1999; 340: 1056Clinical Question: Is a restrictive or liberal strategy of red cell transfusion moreeffective w/ respect to mortality in critically ill patients?Clinical Scenario: 67 y/o white male with history of seizures was intubated andtransferred to the MRICU after aspirating and developing aspiration pneumonia. Duringcourse of hospitalization the patient’s Hg was noted to have slowly trended downward.As a rule we transfused this patient whenever his Hg dropped below 8 in effort to keep itsteadily above 8. Was this appropriate management?Clinical Bottom Line: This study suggest that a restrictive strategy (maintaining Hgbetween 7 and 9 and only transfusing when Hg

Comments/Concerns:-well randomized groups-study only partially blinded; health care providers not blinded to study-study performed on limited population with many exclusion criteria for patients-refusal on the part of patients, their surrogates, or attending physicians may affect thegeneralizability of the results; a greater proportion of patients w/ severe cardiac diseasethan with other types of disease had physicians who declined to enroll them in the study-there is concern about the adverse affects of anemia considering that there are 2 largecohort studies that found increasing severity of anemia was associated with adisproportionate increase in mortality rated among patients with ischemic heart disease;although this study did not have more adverse outcomes in patients w/ cardiovasculardisease using the restrictive strategy; this difference may have due to confounding or aninability to document negative effects of transfusion in the observational studies