Application of fiberoptic sensors for the study of hepatic dysoxia in swine hemorrhagic shock

Soller, Babs R.; Heard, Stephen O.; Cingo, N.; Hsi, Charles; Favreau, Janice; Khan, Tania; Ross, Randy; Puyana, Juan Carlos

doi:10.1097/00003246-200107000-00023

Cited by 41 publications

(27 citation statements)

References 15 publications

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“…pHm is significantly decreased at an LBNP level of Ϫ70 mmHg, corresponding to a fall in PmO 2 to 27.4 Ϯ 1.7 mmHg. We previously demonstrated a similar relationship between tissue pH and tissue PO 2 in swine liver during hemorrhagic shock (27). In this animal study, measurements of tissue pH and PO 2 with invasive sensors demonstrated a breakpoint (PO 2 crit) where pH began to decrease after tissue PO 2 had decreased to 22.3 Ϯ 3.8 mmHg (linear model; Ref.…”

Section: Discussionsupporting

confidence: 62%

“…It is also possible to determine muscle pH (pHm) using NIRS (28, 37). In swine hemorrhage, tissue pH is significantly more sensitive to shock than measures of arterial and venous pH (26), and depressed tissue pH is strongly associated with negative outcomes (27). From a practical standpoint, NIRS instruments can be made small and portable, allowing them to be used for rapid, noninvasive patient assessment both inside and outside the hospital.…”

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confidence: 99%

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Noninvasively determined muscle oxygen saturation is an early indicator of central hypovolemia in humans

Soller¹,

Yang²,

Soyemi³

et al. 2008

Journal of Applied Physiology

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Ten healthy human volunteers were subjected to progressive lower body negative pressure (LBNP) to the onset of cardiovascular collapse to compare the response of noninvasively determined skin and fat corrected deep muscle oxygen saturation (SmO2) and pH to standard hemodynamic parameters for early detection of imminent hemodynamic instability. Muscle SmO2 and pH were determined with a novel near infrared spectroscopic (NIRS) technique. Heart rate (HR) was measured continuously via ECG, and arterial blood pressure (BP) and stroke volume (SV) were obtained noninvasively via Finometer and impedance cardiography on a beat-to-beat basis. SmO2 and SV were significantly decreased during the first LBNP level (-15 mmHg), whereas HR and BP were late indicators of impending cardiovascular collapse. SmO2 declined in parallel with SV and inversely with total peripheral resistance, suggesting, in this model, that SmO2 is an early indicator of a reduction in oxygen delivery through vasoconstriction. Muscle pH decreased later, suggesting an imbalance between delivery and demand. Spectroscopic determination of SmO2 is noninvasive and continuous, providing an early indication of impending cardiovascular collapse resulting from progressive reduction in central blood volume.

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Section: Discussionsupporting

confidence: 62%

mentioning

confidence: 99%

Noninvasively determined muscle oxygen saturation is an early indicator of central hypovolemia in humans

Soller¹,

Yang²,

Soyemi³

et al. 2008

Journal of Applied Physiology

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“…Unfortunately, no data are available on the in vivo oxygen partial pressure in rainbow trout liver tissue. In mammalian liver tissue, oxygen levels detected are in the range of 4-6·kPa, whereas at concentrations of 1.5-1.7·kPa, oxygen availability no longer matches consumption (Soller et al, 2001;Brooks et al, 2004). 'Physiologically normoxic' and 'critical' oxygen tensions correspond with 5-3% and 1% O 2 levels in gas phase, respectively.…”

Section: Discussionmentioning

confidence: 98%

Hypoxic responses of Na+/K+ ATPase in trout hepatocytes

Bogdanova

Grenacher

Nikinmaa

et al. 2005

Journal of Experimental Biology

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SUMMARY Reduction in oxygenation induces inhibition of Na+/K+ATPase in a number of cells and tissues, including hepatocytes. When not reversed, decrease in Na+/K+ pump activity leads to a gradual Na+ accumulation, cell swelling and death. However, when accompanied by suppression of dissipative cation pathways, it has also been shown to be a beneficial adaptive strategy used by some hypoxia-tolerant species to reduce ATP consumption during prolonged periods of anoxia. This study aims to investigate acute hypoxic responses of the Na+/K+ ATPase in primary cultures of trout hepatocytes. Gradual decrease in oxygenation was followed by an instantaneous transient dose-dependent downregulation of the Na+/K+ ATPase transport activity, but was without an effect on hydrolytic function of the enzyme. Hypoxia-induced inhibition of active K+ influx was reversed spontaneously when hypoxic incubation time exceeded 20 min. The stimulating effect of prolonged hypoxic exposure on the Na+/K+ pump is most probably secondary to hypoxia-induced activation of the Na+/H+ exchanger with the following Na+accumulation leading to Na+/K+ ATPase activation. Hypoxia-induced inhibition of the Na+/K+ pump was not caused by ATP depletion or global oxidative stress. However, local controlled production of reactive oxygen species seems to play an important role in hypoxia-induced regulation of the Na+/K+ ATPase. Treatment of cells with mercaptopropionyl glycine (MPG), a scavenger of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{O}\mathrm{H}^{.-}\) \end{document}, abolished hypoxia-induced inhibition of the Na+/K+ ATPase. Earlier on we have shown that activation of Na+/H+ exchanger under hypoxic conditions can be opposed by MPG treatment as well. Taken together our results suggest that regulation of both oxygen-sensitive transporters may be accomplished by local changes in free radical production.

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“…In animal models, such prolonged increases in P L CO 2 are associated with hepatocellular damage [11]. The aim of this study was to describe the changes that occur in liver tissue pH, P L CO 2 , and P L O 2 during IPC and to define the optimal IPC regime, using P L CO 2 as a predictor of hepatocellular damage.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Hepatic Vascular Inflow Occlusion on Liver Tissue pH, Carbon Dioxide, and Oxygen Partial Pressures: Defining the Optimal Clamp/Release Regime for Intermittent Portal Clamping

Brooks

Hammond

Girling

et al. 2007

Journal of Surgical Research

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Application of fiberoptic sensors for the study of hepatic dysoxia in swine hemorrhagic shock

Cited by 41 publications

References 15 publications

Noninvasively determined muscle oxygen saturation is an early indicator of central hypovolemia in humans

Noninvasively determined muscle oxygen saturation is an early indicator of central hypovolemia in humans

Hypoxic responses of Na+/K+ ATPase in trout hepatocytes

The Effect of Hepatic Vascular Inflow Occlusion on Liver Tissue pH, Carbon Dioxide, and Oxygen Partial Pressures: Defining the Optimal Clamp/Release Regime for Intermittent Portal Clamping

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