Desjardins P, Turgeon AF, Tremblay MH, Lauzier F, Zarychanski R, Boutin A, Moore L, McIntyre L, English SW, Rigamonti A, Lacroix J, Fergusson DA.;Crit Care. 2012 Apr 2;16(2):R54.
Introduction: Accumulating evidence suggests that, in critically ill patients, a lower hemoglobin transfusion threshold is safe. However, the optimal hemoglobin level and associated transfusion threshold remain unknown in neurocritically ill patients.
Methods: We conducted a systematic review of comparative studies (randomized and non-randomized) to evaluate the effect of hemoglobin levels on mortality, neurological function, intensive care unit (ICU) and hospital length of stay, duration of mechanical ventilation and multiple organ failure in adult and pediatric neurocritically ill patients. We searched MEDLINE, The Cochrane Central Register of Controlled Trials, Embase, Web of Knowledge and Google Scholar. Studies focusing on any neurocritical care conditions were included. Data are presented using odds ratios for dichotomous outcomes and mean differences for continuous outcomes.
Results: Among 4310 retrieved records, six studies met inclusion criteria (n=537). Four studies were conducted in traumatic brain injury (TBI), one in subarachnoid hemorrhage (SAH) and one in a mixed population of neurocritically ill patients. The minimal hemoglobin levels or transfusion thresholds ranged from 7 to 10 g/dL in the lower Hb groups and from 9.3 to 11.5 g/dL in the higher Hb groups. Three studies had a low risk of bias and three had a high risk of bias. No effect was observed on mortality, duration of mechanical ventilation or multiple organ failure. In studies reporting on length of stay (n=4), one reported a significant shorter ICU stay (mean -11.4 days [95% confidence interval: -16.1,-6.7]) and one a shorter hospital stay (mean -5.7 days [-10.3,-1.1]) in the lower Hb groups, while the other two found no significant association.
Conclusions: We found insufficient evidence to confirm or refute a difference in effect between lower and higher Hb groups in neurocritically ill patients. Considering the lack of evidence regarding long-term neurological functional outcomes and the high risk of bias of half the studies, no recommendation can be made regarding which hemoglobin level to target and which associated transfusion strategy (restrictive or liberal) to favor in neurocritically ill patients.
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