Hyperoxic ventilation at the critical hematocrit: Effects on myocardial perfusion and function

Kemming, Gregor; Meisner, Franz; Meier, Jens; Tillmanns, Jochen; Thein, E.; Eriskat, Jörg; Häbler, O.

doi:10.1111/j.0001-5172.2004.00460.x

Cited by 25 publications

(17 citation statements)

References 42 publications

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“…We did not examine a response curve to graded level of hemodilution because targeting hematocrit values Ͻ25% was associated with unstable hemodynamic condition following surgical preparation. The occurrence of cardiac failure has been documented during graded hemodilution at hematocrit values Ͻ10% in healthy anesthetized animals (49) and around 20 -22% in those with a critical coronary stenosis (18, 40 -42). The importance of hemodynamic stability during acute coronary occlusion should be emphasized since any decrease in blood pressure, even within the normal range, has been shown to worsen myocardial damage (29).…”

Section: Discussionmentioning

confidence: 99%

Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion*

Licker

Mariéthoz²,

Costa³

et al. 2005

Critical Care Medicine

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Section: Discussionmentioning

confidence: 99%

Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion*

Licker

Mariéthoz²,

Costa³

et al. 2005

Critical Care Medicine

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“…A high F i O 2 may lead to vasoconstriction in tissue beds, e.g. coronary vasoconstriction [24] . Hyperoxia may cause maldistribution of blood flow and deterioration of blood flow at the level of the distribution vessels as a protective mechanism against high p O 2 , leading to decreased oxygen uptake in spite of unchanged O 2 delivery [25] .…”

Section: Discussionmentioning

confidence: 99%

Effect of Supplemental Oxygen versus Dobutamine Administration on Liver Oxygen Tension in dPP-Guided Normovolemic Pigs

et al. 2009

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Background: Difference in pulse pressure (dPP) confirms adequate intravascular filling as a prerequisite for tissue perfusion. We hypothesized that both oxygen and dobutamine increase liver tissue oxygen tension (ptO₂). Methods: Eight anesthetized pigs received dPP-guided fluid management. Hepatic pO₂ was measured with Clark-type electrodes placed subcapsularly, and on the liver surface. Pigs received: (1) supplemental oxygen (F_iO₂ 1.0); (2) dobutamine 2.5 μg/kg/min, and (3) dobutamine 5 μg/kg/min. Data were analyzed using repeated-measures ANOVA followed by a Tukey post-test for multiple comparisons. ptO₂measured subcapsularly and at the liver surface were compared using the Bland-Altman plot. Results: Variation in F_iO₂ changed local hepatic tissue ptO₂ [subcapsular measurement: 39 ± 12 (F_iO₂ 0.3), 89 ± 35 mm Hg (F_iO₂ 1.0, p = 0.01 vs. F_iO₂ 0.3), 44 ± 10 mm Hg (F_iO₂ 0.3, p = 0.05 vs. F_iO₂ 1.0); surface measurement: 52 ± 35 (F_iO₂ 0.3), 112 ± 24 mm Hg (F_iO₂ 1.0, p = 0.001 vs. F_iO₂ 0.3), 54 ± 24 mm Hg (F_iO₂ 0.3, p = 0.001 vs. F_iO₂ 1.0)]. Surface measurements were widely scattered compared to subcapsular measurements (bias: –15 mm Hg, precision: 76.3 mm Hg). Dobutamine did not affect hepatic oxygenation. Conclusion: Supplemental oxygen increased hepatic tissue pO₂ while dobutamine did not. Although less invasive, the use of surface measurements is discouraged.

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“…Interestingly, an increase in Hb concentration from 6.0 to 7.8 g/dl with RBC transfusion is capable of reverting hemodilution-induced dysfunctions (24). Other studies have shown that tolerance to moderate hemodilution can be effectively managed with hyperoxic ventilation, which improves tissue oxygenation and survival (15,19). These beneficial effects have been attributed to an increase in arterial O 2 content via an increase of physically dissolved O 2 in the plasma, an increase in MAP, and coronary perfusion pressure, due to hyperoxic arteriolar vasoconstriction.…”

Section: Discussionmentioning

confidence: 99%

Isovolemic exchange transfusion with increasing concentrations of low oxygen affinity hemoglobin solution limits oxygen delivery due to vasoconstriction

Cabrales¹,

Tsai²,

Intaglietta³

2008

American Journal of Physiology-Heart and Circulatory Physiology

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Cabrales P, Tsai AG, Intaglietta M. Isovolemic exchange transfusion with increasing concentrations of low oxygen affinity hemoglobin solution limits oxygen delivery due to vasoconstriction. Am J Physiol Heart Circ Physiol 295: H2212-H2218, 2008. First published October 3, 2008 doi:10.1152/ajpheart.00751.2008.-O 2-carrying fluids based on hemoglobin (Hb) are in various stages of clinical trials to determine their suitability as O 2-carrying plasma expanders. Polymerized Hb solutions are characterized by their vasoactivity, low O 2 affinity, oncotic effect, prolonged shelf life, and stability. Physiological responses to facilitated O 2 transport after exchange transfusion with polymerized bovine Hb (PBH) were studied in the hamster window chamber model during acute moderate anemia to determine how PBH affects microvascular perfusion and tissue oxygenation. The anemic state [29% hematocrit (Hct)] was induced by hemodilution with a plasma expander (70 kDa dextran). After hemodilution, animals were randomly assigned to different exchange transfusion groups. Study groups were based on the concentration of PBH used, namely: PBH at 13 g Hb/dl [PBH13], PBH diluted to 8 (PBH8) or 4 (PBH4) g Hb/dl in albumin solution at matching colloidal osmotic pressure (COP), and no PBH (only albumin solution) at matching COP (PBH0). Measurement of systemic parameters, microvascular hemodynamics, capillary perfusion, and intravascular and tissue O 2 levels was performed at 18% Hct. Restitution of O2-carrying capacity with PBH13 increased arterial pressure and triggered vasoconstriction, low perfusion, and high peripheral resistance. PBH4 and PBH0 exhibited lower arterial pressures compared with PBH13. Exchange transfused animals with PBH8 and PBH4 better maintained perfusion and functional capillary density than PBH13. Blood gas parameters and acid-base balance were recovered proportional to microvascular perfusion. Arterial O 2 tensions were improved with PBH4 and PBH8 by preventing O 2 precapillary release and increasing O2 reserve. Further studies to establish PBH optimal dosage, efficacy, safety, and its effect on outcome are indicated before Hb-based O 2-carrying blood substitutes are implemented in routine practice. microcirculation; red blood cells; hemodilution; functional capillary density; hemoglobin oxygen affinity; tissue oxygen.BLOOD SUBSTITUTES ARE in continued development, driven in part by the public perception that the blood supply is not safe and looming shortages (18). However, blood safety, related to the transmission of viral diseases, is no longer a major concern in the United States, and blood shortages have not materialized due to continued development of surgical techniques that reduce blood losses and lower transfusion triggers (18). Despite these advances, the development of effective blood substitutes that maintain blood volume (BV) and deliver O 2 remains a priority for emergency combat care, as well as for severe blood losses associated with trauma. Blood is a vital public health resource that must be read...

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Hyperoxic ventilation at the critical hematocrit: Effects on myocardial perfusion and function

Abstract: Hyperoxic ventilation at Hctcrit is followed by coronary vasoconstriction and reduction of coronary blood flow. However, myocardial oxygenation and function is maintained, as increased O2-content (in particular dissolved O2) preserves myocardial oxygenation.

Cited by 25 publications

References 42 publications

Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion*

Cardioprotective effects of acute isovolemic hemodilution in a rat model of transient coronary occlusion*

Effect of Supplemental Oxygen versus Dobutamine Administration on Liver Oxygen Tension in dPP-Guided Normovolemic Pigs

Isovolemic exchange transfusion with increasing concentrations of low oxygen affinity hemoglobin solution limits oxygen delivery due to vasoconstriction

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