Oxygen availability during hypothermic cardiopulmonary bypass

Fisher, A; Foëx, P.; Emerson, PaulineM.; Darley, J.; Aimls,; Rauscher, L A

doi:10.1097/00003246-197705000-00007

Cited by 15 publications

(7 citation statements)

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“…This is consistent with the effect of hypothermia on the shift of the ODC. 29 For P 50 calculations, we used the mixed venous samples obtained at the corresponding sampling time points. Because all of our patients had a PaO 2 of at least 100 mm Hg, shifts of the ODC do not affect substantially the saturation.…”

Section: Discussionmentioning

confidence: 99%

Oxygen availability during orthotopic liver transplantation

Kostopanagiotou

Smyrniotis

Theodoraki

et al. 2003

Liver Transplantation

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Studies have stressed the role of adequate tissue oxygenation in the light of an optimal patient outcome and allograft viability in liver transplantation. The practice of monitoring conventional hemodynamic parameters during liver transplantation could be complemented by parameters assessing real oxygen availability. In the present prospective study, real arterial available oxygen content (CavlO 2 ) and its extraction ratio (O 2 ERavl) were calculated. These parameters include the effect of changes in oxyhemoglobin dissociation curve (ODC; expressed by P 50 ) on oxygen availability, under the different circumstances occurring during liver transplantation. Sixteen adult cirrhotic patients were studied during orthotopic liver transplantation with the use of venovenous bypass. Classic hemodynamic measurements using a Swan-Ganz thermodilution catheter and arterial and mixed venous blood gas analysis were performed, and P 50 , oxygen deliv-

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Section: Discussionmentioning

confidence: 99%

Oxygen availability during orthotopic liver transplantation

Kostopanagiotou

Smyrniotis

Theodoraki

et al. 2003

Liver Transplantation

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“…This corresponds with observations during cooling from 28°C in our animals showing a linear drop in a-v O 2 difference, indicating excess O 2 availability. Several authors have described effects of temperature on the human O 2 -Hb dissociation curve (2,9,11,12). In the present experiments, pH was maintained at 7.4 (pH-stat strategy) during stable hypothermia (Ͻ20°C), when respiration was supported, to induce a rightward shift of the O 2 -Hb dissociation curve and facilitate (theoretically) O 2 dissociation from Hb at the tissue level.…”

Section: Tissue O 2 Supplymentioning

confidence: 91%

Is oxygen supply a limiting factor for survival during rewarming from profound hypothermia?

Kondratiev¹,

Flemming²,

Myhre³

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

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Kondratiev, Timofei V., Kristina Flemming, Eivind S. P. Myhre, Mikhail A. Sovershaev, and Torkjel Tveita. Is oxygen supply a limiting factor for survival during rewarming from profound hypothermia? Am J Physiol Heart Circ Physiol 291: H441-H450, 2006. First published February 3, 2006 doi:10.1152/ajpheart.01229.2005.-It has been postulated that unsuccessful resuscitation of victims of accidental hypothermia is caused by insufficient tissue oxygenation. The aim of this study was to test whether inadequate O2 supply and/or malfunctioning O2 extraction occur during rewarming from deep/ profound hypothermia of different duration. Three groups of rats (n ϭ 7 each) were used: group 1 served as normothermic control for 5 h; groups 2 and 3 were core cooled to 15°C, kept at 15°C for 1 and 5 h, respectively, and then rewarmed. In both hypothermic groups, cardiac output (CO) decreased spontaneously by Ͼ50% in response to cooling. O2 consumption fell to less than one-third during cooling but recovered completely in both groups during rewarming. During hypothermia, circulating blood volume in both groups was reduced to approximately one-third of baseline, indicating that some vascular beds were critically perfused during hypothermia. CO recovered completely in animals rewarmed after 1 h (group 2) but recovered to only 60% in those rewarmed after 5 h (group 3), whereas blood volume increased to approximately three-fourths of baseline in both groups. Metabolic acidosis was observed only after 5 h of hypothermia (15°C). A significant increase in myocardial tissue heat shock protein 70 after rewarming in group 3, but not in group 2, indicates an association with the duration of hypothermia. Thus mechanisms facilitating O2 extraction function well during deep/profound hypothermia, and, despite low CO, O2 supply was not a limiting factor for survival in the present experiments. resuscitation; oxygen transport; oxygen consumption; heat shock protein 70; blood volume LITTLE IS KNOWN about the pathophysiology of tissue oxygenation during hypothermia in homeothermic experimental animals. Deranged tissue oxygenation has been postulated to be an important determinant for survival during prolonged (several hours) hypothermia as well as during rewarming after acute (a few hours) hypothermia. Hypothermia decreases the metabolic rate of a homeothermic organism. In clinical medicine, deliberate hypothermia has been used to depress metabolic rate and, thus, vulnerability of the tissue to ischemic damage. Cooling slows tissue body O 2 consumption (V O 2 ) and CO 2 production in parallel: ϳ4 -9% per 1°C (6,14,27). Short exposure time and low level of hypothermia are accepted as essential factors for a favorable outcome after rewarming. Thus, when hypothermia is used during, e.g., cardiac surgery, time and degree of temperature reduction are kept to a minimum. On the contrary, a victim of accidental hypothermia is frequently exposed to deep hypothermia for hours. This prolonged exposure and deep hypothermia are strongly related to failure of the...

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“…Although hypothermia is used to decrease the metabolic rate and the vulnerability of tissue to ischemic damage, it also results in a series of undesirable physiologic responses that may limit DO 2 to the tissues. These responses include a leftward shift in the oxyhemoglobin dissociation curve, i.e., an increase in affinity of hemoglobin for oxygen, 9,14 an increase in pH that further shifts the curve leftward, redistribution of blood flow away from splanchnic organs 15 and a variable degree of vasoconstriction. Furthermore, rapid cooling by an integrated heat exchanger may result in nonuniformity of body temperature during the initial period of hypothermia, causing uneven tissue perfusion and VO 2 .…”

Section: Discussionmentioning

confidence: 99%

Evidence for a significant myocardial contribution to total metabolic burden during hypothermic cardiopulmonary bypass: a study of continuously measured oxygen consumption and arterial lactate levels in pigs

Stokoe

Konstantinov³

et al. 2005

Perfusion

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Inadequate tissue oxygenation persists throughout hypothermic CPB. The rise in systemic VO2 and lactate immediately after ACC release may reflect inadequate oxygen transport within the myocardium during ischemia and manifest on reperfusion. This simple technique may be used to provide important information regarding the dynamic balance of systemic and myocardial oxygen transport during ischemia-reperfusion.

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Oxygen availability during hypothermic cardiopulmonary bypass

Cited by 15 publications

References 0 publications

Oxygen availability during orthotopic liver transplantation

Oxygen availability during orthotopic liver transplantation

Is oxygen supply a limiting factor for survival during rewarming from profound hypothermia?

Evidence for a significant myocardial contribution to total metabolic burden during hypothermic cardiopulmonary bypass: a study of continuously measured oxygen consumption and arterial lactate levels in pigs

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