Low hemoglobin levels are associated with lower cerebral saturations and poor outcome after cardiac arrest.
OBJECTIVE
Post-cardiac arrest (CA) patients have a large cerebral penumbra at risk for secondary ischemic damage in case of suboptimal brain oxygenation during ICU stay. The aims of this study were to investigate the association between hemoglobin, cerebral oxygenation (SctO2) and outcome in post-CA patients.


METHODS
Prospective observational study in 82 post-CA patients. Hemoglobin, a corresponding SctO2 measured by NIRS and SVO2 in patients with a pulmonary artery catheter (n=62) were determined hourly during hypothermia in the first 24h of ICU stay.


RESULTS
We found a strong linear relationship between hemoglobin and mean SctO2 (SctO2=0.70×hemoglobin+56 (R(2) 0.84, p=10(-6))). Hemoglobin levels below 10g/dl generally resulted in lower brain oxygenation. There was a significant association between good neurological outcome (43/82 patients in CPC 1-2 at 180 days post-CA) and admission hemoglobin above 13g/dl (OR 2.76, 95% CI 1.09:7.00, p=0.03) or mean hemoglobin above 12.3g/dl (OR 2.88, 95%CI 1.02:8.16, p=0.04). This association was entirely driven by results obtained in patients with a mean SVO2 below 70% (OR 6.25, 95%CI 1.33:29.43, p=0.01) and a mean SctO2 below 62.5% (OR 5.87, 95%CI 1.08:32.00, p=0.03).


CONCLUSIONS
Hemoglobin levels below 10g/dl generally resulted in lower cerebral oxygenation. Average hemoglobin levels below 12.3g/dl were associated with worse outcome in patients with suboptimal SVO2 or SctO2. The safety of a universal restrictive transfusion threshold of 7g/dl can be questioned in post-CA patients.
Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium. Electronic address: Koen.ameloot@zol.be.
K
K
Ameloot
Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium; Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
C
C
Genbrugge
Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium; Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
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I
Meex
Department of Cardiology, University Hospitals Leuven, Leuven, Belgium.
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S
Janssens
Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium.
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W
Boer
Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
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W
Mullens
Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium.
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B
Ferdinande
Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium.
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M
Dupont
Department of Cardiology, Ziekenhuis Oost-Limburg, Genk, Belgium; Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
J
J
Dens
Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium; Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
C
C
De Deyne
D001530:Belgium / Q000453:epidemiology; D001921:Brain / Q000378:metabolism*; D002545:Brain Ischemia / Q000453:epidemiology / Q000209:etiology / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006323:Heart Arrest / Q000097:blood* / Q000150:complications / Q000628:therapy; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology*; D011379:Prognosis; D011446:Prospective Studies; D015996:Survival Rate / Q000639:trends
D006454:Hemoglobins
Cerebral saturation; Hemoglobin; Post-cardiac arrest