Changes in tissue oxygen tension, venous saturation, and Fick‐based assessments of cardiac output during hyperoxia

Perry, Dorothy A.; Thomson, Lindsay M.; Pigula, Frank A.; Polizzotti, Brian D.; DiNardo, James A.; Nedder, Arthur; Kheir, John N.

doi:10.1111/aas.13225

Cited by 11 publications

(13 citation statements)

References 37 publications

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Section: Increased Fio 2 Vs Fick-cocontrasting

confidence: 93%

“…In a similar study on swine, Perry et al evaluated the accuracy of Fick-CO assessments with an increase in FIO2, [30] while their conclusions contradict our findings. Further analysis of their data revealed that the SvO2 values were much lower in swine (58.2 ±7.27% under FIO2 = 0.6, and 61.0 ±6.7% under FIO2 = 0.8) than in the humans in the current study (79.9 ±6.4% under FIO2 = 0.56, and 85.1 ±5.6% under FIO2 = 0.92).…”

Section: Increased Fio 2 Vs Fick-cocontrasting

confidence: 93%

“…proved that during hyperoxia, there could be an increase in SvO2 levels due to an increase in tissue oxygen tension (via the Fickian diffusion of excess dissolved oxygen), resulting in elevated PvO2 values. [30] A modest increase in PvO2 could lead to a significant increase in SvO2 due to the sigmoid shape of the oxygen-Hb dissociation curve. [12] Ultimately, the affected value of SvO2 caused by increased FIO2 could conceal a situation involving insufficient oxygen delivery, thereby hindering therapy.…”

Section: Increased Fio 2 Vs Svomentioning

confidence: 99%

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Increased FIO2 Influences SvO2 Interpretation and Accuracy of Fick-based Cardiac Output Assessment in Cardiac Surgery Patients

Lin¹,

Chang²,

Lin³

et al. 2020

Preprint

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Background: The study aimed to reveal how the fraction of inspired oxygen (FIO2) affected the value of mixed venous oxygen saturation (SvO2) and the accuracy of Fick-equation-based cardiac output (Fick-CO). Methods: Forty-two adult patients who underwent elective cardiac surgery were enrolled and randomly divided into two groups: FIO2 <0.7 or >0.85. Under stable general anesthesia, thermodilution-derived cardiac output (TD-CO), SvO2, PvO2, hemoglobin, SaO2, PaO2, and blood pH levels were recorded before surgical incision. Results: Significant differences in FIO2 values were observed between the two groups (0.56 ±0.08 in the <70% group and 0.92 ±0.03 in the >0.85 group; p <0.0001). The increasing FIO2 values lead to increases in SvO2, PvO2, and PaO2, with little effects on cardiac output and hemoglobin levels. When comparing to TD-CO, the calculated Fick-CO in both groups had moderate Pearson correlations and similar linear regression results. Although the FIO2 <0.7 group presented a less mean bias and a smaller limits of agreement, neither group met the percentage error criteria of <30% in Bland-Altman analysis.Conclusions: Increased FIO2 may influence the interpretation of SvO2 and the exacerbation of Fick-CO estimation, which could affect clinical management. Trial Registration: ClinicalTrials.gov ID number: NCT04265924. Retrospectively registered (Date of registration: February 12, 2020).

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Section: Increased Fio 2 Vs Fick-cocontrasting

confidence: 93%

Section: Increased Fio 2 Vs Fick-cocontrasting

confidence: 93%

Section: Increased Fio 2 Vs Svomentioning

confidence: 99%

See 1 more Smart Citation

Increased FIO2 Influences SvO2 Interpretation and Accuracy of Fick-based Cardiac Output Assessment in Cardiac Surgery Patients

Lin¹,

Chang²,

Lin³

et al. 2020

Preprint

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“…This hypothesis, however, is not supported by animal and human experiments. In pigs subjected to increasing FiO 2 , both cerebral and myocardial tissue oxygen tension (PtO 2 ) increased proportionally with increasing FiO 2 [53,54]. When pigs were subjected to haemodilution until their electrocardiogram showed ischaemic changes, hyperoxia, although it caused coronary vasoconstriction and reduced coronary blood flow, preserved myocardial oxygenation and improved electrocardiogram abnormalities [55].…”

Section: Vasoconstriction and Cellular Oxygen Deliverymentioning

confidence: 99%

Perioperative Hyperoxyphobia: Justified or Not? Benefits and Harms of Hyperoxia during Surgery

Weenink

Jonge

Hulst

et al. 2020

JCM

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The use of an inspiratory oxygen fraction of 0.80 during surgery is a topic of ongoing debate. Opponents claim that increased oxidative stress, atelectasis, and impaired oxygen delivery due to hyperoxic vasoconstriction are detrimental. Proponents point to the beneficial effects on the incidence of surgical site infections and postoperative nausea and vomiting. Also, hyperoxygenation is thought to extend the safety margin in case of acute intraoperative emergencies. This review provides a comprehensive risk-benefit analysis for the use of perioperative hyperoxia in noncritically ill adults based on clinical evidence and supported by physiological deduction where needed. Data from the field of hyperbaric medicine, as a model of extreme hyperoxygenation, are extrapolated to the perioperative setting. We ultimately conclude that current evidence is in favour of hyperoxia in noncritically ill intubated adult surgical patients.

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“…Nitrite reduced heart rate in hypoxia in both experiments without impacting V O2, this means that according to the Fick equation, either stroke volume must increase to maintain cardiac output, or oxygen delivery to the systemic tissue must become more efficient to maintain V O2 (50). The mechanism cannot be determined by our current data set.…”

Section: Discussionmentioning

confidence: 69%

Effects of nitrite on long-term peripheral chemoreflex in healthy and high fat diet-fed rats

Delloro¹

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Inorganic nitrate and nitrite supplementation improves endothelial function, decreases blood pressure, increases ejection fraction, and decreases overall weight. It also attenuates the hypoxic ventilatory response (HVR) in healthy humans. The HVR is increased in obese humans when compared to healthy individuals. Therefore, we hypothesize that HVR increases in a rat model of obesity and this increase is blunted by nitrite supplementation. First, we tested the hypothesis that nitrite supplementation decreases HVR in healthy, adult rats. Twelve, two-month-old, Fischer-344 rats were broken into two groups: rats fed a standard diet with additional nitrite supplementation (Nitrite) and rats fed a standard diet with no additional supplementation. After two months of nitrite supplementation, plethysmography and gas analysis was used to measure ventilation and metabolism at 21%, 15%, 12%, and 9% oxygen. In the second experiment, Twenty-one, seven-month-old, Fischer-344 rats were divided into three groups: rats fed a high fat diet (HFD), rats fed a high fat diet with additional nitrite supplementation in their drinking water (HFD+Nitrite), and rats fed a standard diet (Control). After 14 months of diet and nitrite supplementation, all three groups underwent plethysmography as in experiment 1. In the first experiment, nitrite supplementation significantly reduced HVR. In the longterm nitrite supplementation cohort, contrary to data in humans, the HVR was reduced in obese rats compared to control, nitrite did not alter this obesity-induced decrease in HVR. Nitrite did cause a significant increase in rate of oxygen consumption (V O2) when compared to both HFD rats and control rats. Future studies are needed to determine the mechanisms behind the impact of these interventions on HVR.

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Changes in tissue oxygen tension, venous saturation, and Fick‐based assessments of cardiac output during hyperoxia

Abstract: SvO acutely changes following changes in PaO even absent changes in measured DO . This may lead to errors in Fick estimates of CI. Further work is necessary to understand the impact of this phenomenon in disease states.

Cited by 11 publications

References 37 publications

Increased FIO2 Influences SvO2 Interpretation and Accuracy of Fick-based Cardiac Output Assessment in Cardiac Surgery Patients

Increased FIO2 Influences SvO2 Interpretation and Accuracy of Fick-based Cardiac Output Assessment in Cardiac Surgery Patients

Perioperative Hyperoxyphobia: Justified or Not? Benefits and Harms of Hyperoxia during Surgery

Effects of nitrite on long-term peripheral chemoreflex in healthy and high fat diet-fed rats

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