Cardiovascular Responses, Hemodynamics and Oxygen Transport to Tissue during Moderate Isovolemic Hemodilution in Pigs

Trouwborst, A.; Tenbrinck, R.; Fennema, M.; Bucx, M. J. L.; Broek, W. G. M. v.d.; Trouwborst-Weber, B. K.

doi:10.1007/978-1-4684-8181-5_100

Cited by 10 publications

(3 citation statements)

References 16 publications

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“…Large differences in the tolerance of organ systems to conditions of decreased O 2 delivery (DO 2 ) exist. However, as soon as the systemic oxygen delivery falls below a critical point, compensatory mechanisms are getting insufficient and oxygen consumption (V O 2 ) becomes dependent on supply (4,28,32,36,38). Although compensatory mechanisms preserve vital organ oxygenation over a wide range of decreasing hematocrit, they may impair tissue oxygenation of critical organs (34,37).…”

mentioning

confidence: 99%

Acute decrease in renal microvascular Po₂ during acute normovolemic hemodilution

Johannes

Mik²,

Nohé³

et al. 2007

American Journal of Physiology-Renal Physiology

121

122

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Johannes T, Mik EG, Nohé B, Unertl KE, Ince C. Acute decrease in renal microvascular PO 2 during acute normovolemic hemodilution. Am J Physiol Renal Physiol 292: F796 -F803, 2007. First published October 31, 2006 doi:10.1152/ajprenal.00206.2006.-Large differences in the tolerance of organ systems to conditions of decreased O2 delivery such as hemodilution exist. The kidney receives ϳ25% of the cardiac output and O2 delivery is in excess of the oxygen demand under normal circumstances. In a rat model of acute normovolemic hemodilution (ANH), we studied the effect of reduced hematocrit on renal regional and microvascular oxygenation. Experiments were performed in 12 anesthetized male Wistar rats. Six animals underwent four steps of ANH (hematocrit 25, 15, 10, and Ͻ10%). Six animals served as time-matched controls. Systemic and renal hemodynamic and oxygenation parameters were monitored. Renal cortical (c) and outer medullary (m) microvascular PO 2 (PO2) and the renal venous PO 2 (PrvO2) were continuously measured by oxygen-dependent quenching of phosphorescence. Despite a significant increase in renal blood flow in the first two steps of ANH, cPO 2 and mPO2 dropped immediately. From the first step onward oxygen consumption (V O2ren) became dependent on oxygen delivery (DO 2ren). With a progressive decrease in hematocrit, a significant correlation between PO 2 and V O2ren could be observed, as well as a PO2 gap between PO2 and P rvO2. Furthermore, there was a high correlation between V O2ren and RBF over a wide range of flows. In conclusion, the oxygen supply to the renal tissue is becoming critical already in an early stage of ANH due to the combination of increased V O2ren, decreased DO2ren, and intrarenal O 2 shunt. This has clinical relevance as recent publications reporting that hemodilution during surgery forms a risk factor for postoperative renal dysfunction.

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mentioning

confidence: 99%

Acute decrease in renal microvascular Po₂ during acute normovolemic hemodilution

Johannes

Mik²,

Nohé³

et al. 2007

American Journal of Physiology-Renal Physiology

121

122

View full text Add to dashboard Cite

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“…There are no significant changes in blood lactate during haemodilution 32 . With a decreasing haematocrit, the oxygen dissociation curve shifts to the right 48,51 . An acute right shift in the oxygen dissociation curve can occur at a haematocrit below 10 % over and above the expected changes due to changes in pH and PaCO2 51 .…”

Section: Effects On Cardiorespiratory Functionmentioning

confidence: 98%

“…As a compensatory effect to the reduced arterial oxygen content, cardiac output increases to maintain oxygen delivery 2,5 . Cardiac output may increase as a result of changes in heart rate or stroke volume or both 12,48,49 . The increase in cardiac output in dogs appears to be due to an increase in heart rate and a reduction in peripheral vascular resistance 12,20,45 .…”

Section: Effects On Cardiorespiratory Functionmentioning

confidence: 99%

Acute normovolaemic haemodilution - is it a solution to reduce perioperative blood transfusions? : review article

Joubert¹

2007

J. S. Afr. Vet. Assoc.

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Haemodilution is a technique used to reduce perioperative homologous blood transfusions. Haemodilution is a poorly investigated technique in veterinary medicine. This article reviews haemodilution as a potential technique to reduce perioperative homologous blood transfusions. The history of haemodilution is briefly reviewed followed by the mathematical basis to haemodilution. The issue of critical oxygen delivery and its implications for haemodilution are discussed. The effects of haemodilution on the patient, including the effects on oxygen transport, blood flow and coagulation are discussed as well as the use of colloids, fluids and blood components in haemodilution. The success and failure of haemodilution in human clinical trials and experimental evidence is discussed. Some guidelines are given for the use of haemodilution in small animal patients in the perioperative setting. It appears in all likelihood that haemodilution has a limited application in cats and other small patients. Haemodilution is most beneficial when the initial haematocrit is high, a low haemodiluted haematocrit is achieved, the patients circulating volume is large and a large amount of blood was lost. It is important to avoid haemoconcentration during surgery as this increases red blood cell loss. Haemodilution is not a substitute for poor surgical technique and inadequate haemostasis intra-operatively. Intravascular volume should be maintained throughout the procedure

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Hemodilution and Oxygen Transport

Trouwborst

Woerkens

Tenbrinck

1992

Oxygen Transport to Tissue XIV

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Cardiovascular Responses, Hemodynamics and Oxygen Transport to Tissue during Moderate Isovolemic Hemodilution in Pigs

Cited by 10 publications

References 16 publications

Acute decrease in renal microvascular Po₂ during acute normovolemic hemodilution

Acute decrease in renal microvascular Po₂ during acute normovolemic hemodilution

Acute normovolaemic haemodilution - is it a solution to reduce perioperative blood transfusions? : review article

Hemodilution and Oxygen Transport

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Cardiovascular Responses, Hemodynamics and Oxygen Transport to Tissue during Moderate Isovolemic Hemodilution in Pigs

Cited by 10 publications

References 16 publications

Acute decrease in renal microvascular Po2 during acute normovolemic hemodilution

Acute decrease in renal microvascular Po2 during acute normovolemic hemodilution

Acute normovolaemic haemodilution - is it a solution to reduce perioperative blood transfusions? : review article

Hemodilution and Oxygen Transport

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Acute decrease in renal microvascular Po₂ during acute normovolemic hemodilution

Acute decrease in renal microvascular Po₂ during acute normovolemic hemodilution