Reassessing the risk of hemodilutional anemia: Some new pieces to an old puzzle

Tsui, Albert K.Y.; Dattani, Neil D.; Marsden, Philip A.; El-Beheiry, Mostafa; Grocott, Hilary P.; Liu, Elaine; Biro, George P.; Mazer, C. David; Hare, Gregory M. T.

doi:10.1007/s12630-010-9329-x

Cited by 40 publications

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References 100 publications

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“…The proposed mechanism for increased MetHb may include NO-mediated Hb oxidation or reduction of nitrite (NO 2 -) by DeoxyHb, as suggested by experimental and clinical studies. 3,[18][19][20][21][22] It will be important to assess these changes in subsequent studies to determine if the increase in MetHb is reflective of activated adaptive mechanisms (nNOS) 7 and/ or increased OxyHb desaturation to DeoxyHb and tissue hypoxia [18][19][20][21][22] during acute hemodilutional anemia.…”

Section: Discussionmentioning

confidence: 99%

“…[1][2][3] The recent finding that mild and moderate cases of anemia are also associated with increased mortality in patients undergoing cardiac and non-cardiac surgery makes this a critically important area of anesthesia research. 4,5 Experimental studies have shown that both hypoxic and nonhypoxic mechanisms may contribute to anemia-induced organ injury and mortality.…”

Section: Résumémentioning

confidence: 99%

“…4,5 Experimental studies have shown that both hypoxic and nonhypoxic mechanisms may contribute to anemia-induced organ injury and mortality. 3,6,7 The complex nature of the cellular mechanisms involved may explain why anemiainduced mortality is not necessarily improved by therapies which increase blood oxygen content, including red blood cell (RBC) transfusions, 8,9 use of erythropoiesis stimulating agents (ESAs), 10 or hemoglobin-based oxygen carriers (HBOCs). 11 Each of these strategies is capable of increasing blood oxygen content but may not increase tissue oxygen delivery.…”

Section: Résumémentioning

confidence: 99%

“…Our research has shown that increased NO production by nitric oxide syntheses (NOSs) may be an important survival mechanism in acute anemia. 3,13,14 We have shown that deficiency of neuronal NOS (nNOS) is associated with increased mortality in a model of hemodilutional anemia, such that mice lacking nNOS die at a mean hemoglobin (Hb) value of 35 gÁL -1 , a level that is significantly higher than nNOS replete mice or humans (*25 gÁL -1 ). 7,15 In search of a clinical biomarker of NOS activation during anemia, we have hypothesized that increased nNOS-derived NO promotes a tissue-plasma NO gradient that favours the oxidation of Hb to MetHb, as shown by the negative correlation between increasing MetHb and decreasing Hb in experimental models of anemia ( Fig.…”

Section: Résumémentioning

confidence: 99%

“…1). 3 In addition, a number of mechanisms have been proposed to explain how local NO production can regulate vascular tone in ''hypoxic'' vascular beds (Fig. 2).…”

Section: Résumémentioning

confidence: 99%

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Plasma methemoglobin as a potential biomarker of anemic stress in humans

Hare

Romaschin

et al. 2012

Can J Anesth/J Can Anesth

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Purpose Transfusion of allogeneic red blood cells (RBCs) is one of the main treatments of acute anemia secondary to blood loss and fluid resuscitation within the operating room. Decisions to transfuse blood are based largely on intermediate biological markers (hemoglobin, arterial oxygen saturation, blood pressure, heart rate) which may not accurately reflect inadequacy of tissue oxygen delivery.Based on experimental studies, we hypothesized that anemia-induced tissue hypoxia activates adaptive mechanisms which promote local vascular nitric oxide (NO) production to improve tissue perfusion and survival during acute anemia. Hemoglobin (Hb) oxidation to methemoglobin (MetHb) may be a byproduct of such local NO production. Therefore, we tested the hypothesis that MetHb is a biomarker of hypoxic-anemic stress during acute hemodilution associated with cardiopulmonary bypass. Methods With institutional ethics approval, routine laboratory arterial blood gas and co-oximetry values were obtained from 295 patients undergoing heart surgery during February 1 to September 30, 2010, and the values were assessed retrospectively. All samples with an arterial oxygen saturation value C90% were included (n = 1,421). The maximal change in Hb associated with hemodilution on cardiopulmonary bypass was determined within 48 hr of surgery (n = 180). A chart review was performed to determine the incidence of RBC transfusion and exogenous nitrate administration. All anonymous data were analyzed by linear regression to determine the relationship between Author contributions Gregory M.T. Hare designed the research, performed the research, contributed novel intellectual input, analyzed the data, and wrote the paper. Alexander Mu performed the research, contributed novel intellectual input, and analyzed the data. Alexander Romaschin designed the research, performed the research, contributed novel intellectual input, and analyzed the data. Nadine Shehata designed the research, performed the research, contributed novel intellectual input, and analyzed the data. W. Scott Beattie designed the research, performed the research, contributed novel intellectual input, analyzed the data, and wrote the paper. C. David Mazer designed the research, performed the research, contributed novel intellectual input, analyzed the data, and wrote the paper. Albert K.Y. Tsui contributed novel intellectual input, analyzed the data, and wrote the paper. RésuméObjectif La transfusion de globules rouges alloge´niques est l'un des principaux traitements de l'ane´mie aigues econdaire a`une perte sanguine et au remplissage liquidien en salle d'ope´ration. La de´cision de transfuser du sang repose essentiellement sur des marqueurs biologiques interme´diaires (he´moglobine, saturation en oxyge`ne du sang arte´riel, pression arte´rielle, fre´quence cardiaque) qui pourraient ne pas refle´ter avec pre´cision l'insuffisance d'apport d'oxyge`ne aux tissus. A`partir d'e´tudes expe´rimentales nous avons fait l'hypothe`se qu'une hypoxie tissulaire induite par l'ane´mie act...

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Section: Discussionmentioning

confidence: 99%

Section: Résumémentioning

confidence: 99%

Section: Résumémentioning

confidence: 99%

Section: Résumémentioning

confidence: 99%

“…1). 3 In addition, a number of mechanisms have been proposed to explain how local NO production can regulate vascular tone in ''hypoxic'' vascular beds (Fig. 2).…”

Section: Résumémentioning

confidence: 99%

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